Patent Publication Number: US-2023159313-A1

Title: Leveling system for lift device

Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 17/079,014, filed Oct. 23, 2020, which is a continuation of U.S. patent application Ser. No. 16/673,162, filed Nov. 4, 2019, which claims the benefit of and priority to (a) U.S. Provisional Patent Application No. 62/755,882, filed Nov. 5, 2018, (b) U.S. Provisional Patent Application No. 62/813,547, filed Mar. 4, 2019, and (c) U.S. Provisional Patent Application No. 62/813,550, filed Mar. 4, 2019, all of which are incorporated herein by reference in their entireties. 
    
    
     BACKGROUND 
     Traditional boom lifts may include a chassis, a turntable coupled to the chassis, and a boom assembly. The boom assembly may include one or more boom sections that are pivotally connected to the turntable. A lift cylinder elevates the one or more boom sections relative to the turntable, thereby elevating an implement (e.g., work platform, forks, etc.) that is coupled to the boom assembly. 
     SUMMARY 
     One embodiment relates to a chassis for a lift device. The chassis includes a base, an arm coupled to the base and configured to support a tractive element, and a plate extending from the arm at an upward angle. The arm includes a steering actuator interface configured to support an end of a steering actuator for the tractive element. The plate is configured to extend past the steering actuator. 
     Another embodiment relates to a chassis for a lift device. The chassis include a base and an arm. The arm has a first end coupled to the base and a second end configured to support a tractive element. A portion of a bottom surface of the arm proximate the second end is angled upward. 
     Still another embodiment relates to a chassis for a lift device. The chassis includes a base. The base defines an interior chamber and an aperture that facilitates passing at least one of hosing or wiring through a wall of the base into the interior chamber. The base has a tab positioned proximate the aperture and that extends from the wall. The tab facilitates securing the at least one of the hosing or the wiring thereto using a retainer. 
     This summary is illustrative only and is not intended to be in any way limiting. Other aspects, inventive features, and advantages of the devices or processes described herein will become apparent in the detailed description set forth herein, taken in conjunction with the accompanying figures, wherein like reference numerals refer to like elements. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a perspective view of a lift device having a chassis, a leveling system, a turntable, and a boom, according to an exemplary embodiment. 
         FIG.  2    is a front perspective view of the chassis and the leveling system of the lift device of  FIG.  1   , according to an exemplary embodiment. 
         FIG.  3    is a top view of the chassis and the leveling system of  FIG.  2   , according to an exemplary embodiment. 
         FIG.  4    is a first side view of the chassis and the leveling system of  FIG.  2   , according to an exemplary embodiment. 
         FIG.  5    is a second side view of the chassis and the leveling system of  FIG.  2   , according to an exemplary embodiment. 
         FIG.  6    is a front view of the chassis and the leveling system of  FIG.  2   , according to an exemplary embodiment. 
         FIG.  7    is a rear view of the chassis and the leveling system of  FIG.  2   , according to an exemplary embodiment. 
         FIG.  8    is a front perspective view of the chassis and the leveling system of the lift device of  FIG.  1   , according to another exemplary embodiment. 
         FIG.  9    is a side perspective view of the chassis and the leveling system of  FIG.  8   , according to an exemplary embodiment. 
         FIG.  10    is a bottom perspective view of the chassis and the leveling system of  FIG.  8   , according to an exemplary embodiment. 
         FIG.  11    is a top view of the chassis and the leveling system of  FIG.  8   , according to an exemplary embodiment. 
         FIGS.  12  and  13    are various top views of the chassis and the leveling system of the lift device of  FIG.  1   , according to another exemplary embodiment. 
         FIGS.  14 - 17    are various views of a steering system of the lift device of  FIG.  1   , according to an exemplary embodiment. 
         FIGS.  18 - 21    are various views of a pressure sensor assembly of the lift device of  FIG.  1   , according to an exemplary embodiment. 
         FIGS.  22 - 24    are various views of a routing feature of the chassis of the lift device of  FIG.  1   , according to an exemplary embodiment. 
         FIG.  25    is a schematic diagram of an actuator circuit for the leveling system of the lift device of  FIG.  1   , according to an exemplary embodiment. 
         FIG.  26    is a schematic block diagram of the leveling system of the lift device of  FIG.  1    in a first configuration, according to an exemplary embodiment. 
         FIG.  27    is a schematic block diagram of the leveling system of the lift device of  FIG.  1    in a second configuration, according to an exemplary embodiment. 
         FIG.  28    is a schematic block diagram of the leveling system of the lift device of  FIG.  1    in a third configuration, according to an exemplary embodiment. 
         FIG.  29    is a schematic block diagram of the leveling system of the lift device of  FIG.  1    in a fourth configuration, according to an exemplary embodiment. 
         FIG.  30    is a schematic block diagram of a control system of the lift device of  FIG.  1   , according to an exemplary embodiment. 
         FIG.  31    is a side view of the lift device of  FIG.  1    in a shipping, transport, or storage mode, according to an exemplary embodiment. 
         FIG.  32    is a block diagram of a method for centering chassis height during an auto level mode, according to an exemplary embodiment. 
         FIG.  33    is a block diagram of a method for initiating a drive command cutout during the auto level mode, according to an exemplary embodiment. 
         FIG.  34    is a block diagram of a method for switching from the auto level mode to a high-speed drive mode, according to an exemplary embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Before turning to the figures, which illustrate certain exemplary embodiments in detail, it should be understood that the present disclosure is not limited to the details or methodology set forth in the description or illustrated in the figures. It should also be understood that the terminology used herein is for the purpose of description only and should not be regarded as limiting. 
     According to an exemplary embodiment, a lift device includes a chassis, a leveling system, and a plurality of tractive elements coupled to the chassis by the leveling system. The leveling system is configured to maintain the chassis of the lift device level relative to gravity (e.g., flat, horizontal, etc.) while stationary and/or while moving (e.g., being driven, etc.). According to an exemplary embodiment, the leveling system includes a first leveling assembly, a second leveling assembly, a third leveling assembly, and a fourth leveling assembly. Each of the first leveling assembly, the second leveling assembly, the third leveling assembly, and the fourth leveling assembly includes (i) a respective trailing arm having a first end pivotally coupled to the chassis, (ii) a respective tractive element coupled to an opposing second end of the respective trailing arm, and (iii) a respective pivot actuator positioned to selectively pivot the trailing arm and the tractive element associated therewith relative to the chassis. 
     In some embodiments, the trailing arms are shaped to maximize the stroke of the pivot actuators. In some embodiments, the pivot actuators include a pressure assembly coupled to cylinders thereof that has a cover or cap that protects pressure sensors of the pressure assembly and/or the cylinders. In some embodiments, one or more of the trailing arms include a steering actuator coupled thereto and to the tractive element thereof. The trailing arms that have steering actuators may have a plate (e.g., an angled plate, etc.) extending therefrom and past the steering actuator thereof. In some embodiments, two of the trialing arms include steering actuators. In some embodiments, all of the trailing arms include steering actuators. In some embodiments, the chassis defines one or more ports that lead to an interior chamber of the chassis. The chassis may include one or more panels that selectively enclose the one or more ports. In some embodiments, the chassis includes one or more routing features that facilitate neatly and efficiently passing a plurality of hoses and/or wiring from the interior chamber through the chassis to the pivot actuators, the steering actuators, and/or drive actuators (e.g., that drive the tractive elements, etc.). In some embodiments, the lift device includes steering sensors positioned to monitor the steering angle of the tractive elements relative to a pivot axis between the tractive elements and the trailing arms. 
     According to an exemplary embodiment, the lift device is operable in a plurality of modes including one or more of a shipping, transport, or storage mode; a discrete braking mode; an adaptive oscillation mode; an auto level mode; or a high-speed drive mode. By way of example, the lift device may include a controller configured to operate the leveling system in the adaptive oscillation mode by selectively and adaptively fluidly coupling two of the pivot actuators of the first leveling assembly, the second leveling assembly, the third leveling assembly, and the fourth leveling assembly, while maintaining the other two of the pivot actuators fluidly decoupled. The two fluidly decoupled actuators may be independently and actively controlled by the controller. 
     The terms “front,” “rear,” “left,” and “right” as used herein are relative terms to provide reference and not necessarily intended to be limiting. “Active control” refers to engaging valves, pumps, motors, etc. with a processing circuit or controller to selectively vary the extension, retraction, etc. of an actuator (e.g., a hydraulic cylinder, etc.) independently of other actuators. “Passive control” refers to actuator extension, retraction, etc. of an individual actuator that is permitted but not independently regulated using a processing circuit or controller. During such passive control, two actuators may be fluidly coupled such that the two actuators “freely float,” however, fluid may be added or removed from the fluidly coupled actuators to increase or decrease the height of a “virtual pivot point” of the fluidly coupled actuators, as is described in more detail herein. 
     As shown in  FIGS.  1 - 13   , a lift device (e.g., an aerial work platform, a telehandler, a boom lift, a scissor lift, etc.), shown as lift device  10 , includes a chassis, shown as lift base  12 . In other embodiments, the lift device  10  is another type of vehicle (e.g., a fire apparatus, a military vehicle, a fire apparatus, an airport rescue fire fighting (“ARFF”) truck, a boom truck, a refuse vehicle, a fork lift, etc.). As shown in  FIG.  1   , the lift base  12  supports a rotatable structure, shown as turntable  14 , and a boom assembly, shown as boom  40 . According to an exemplary embodiment, the turntable  14  is rotatable relative to the lift base  12 . In one embodiment, the turntable  14  includes a counterweight positioned at a rear of the turntable  14 . In other embodiments, the counterweight is otherwise positioned and/or at least a portion of the weight thereof is otherwise distributed throughout the lift device  10  (e.g., on the lift base  12 , on a portion of the boom  40 , etc.). 
     As shown in  FIGS.  1 - 13   , a first end, shown as front end  20 , and an opposing second end, shown as rear end  30 , of the lift base  12  is supported by a plurality of tractive elements, shown as tractive elements  16 . According to the exemplary embodiment shown in  FIGS.  1 - 13   , the tractive elements  16  include wheels. In other embodiments, the tractive elements  16  include track elements. As shown in  FIGS.  2 ,  3 ,  6 , and  11 - 15   , the lift device  10  includes a plurality of drivers, shown as drive actuators  18 . According to an exemplary embodiment, each of the drive actuators  18  is positioned to facilitate independently and selectively driving one of the tractive elements  16  to move the lift device  10 . As shown in  FIGS.  3 ,  6 , and  11   , the lift device  10  only includes drive actuators  18  positioned to drive the front tractive elements  16 . As shown in  FIGS.  12  and  13   , the lift device  10  includes drive actuators  18  positioned to drive the front tractive elements  16  and the rear tractive elements  16 . In some embodiments, the lift device  10  includes a plurality of brakes (e.g., one for each tractive element  16 , brakes  46 , etc.) positioned to independently and selectively restrict rotation of each of the tractive elements  16 . 
     As shown in  FIG.  1   , the boom  40  includes a first boom section, shown as lower boom  50 , and a second boom section, shown as upper boom  70 . In other embodiments, the boom  40  includes a different number and/or arrangement of boom sections (e.g., one, three, etc.). According to an exemplary embodiment, the boom  40  is an articulating boom assembly. In one embodiment, the upper boom  70  is shorter in length than the lower boom  50 . In other embodiments, the upper boom  70  is longer in length than the lower boom  50 . According to another exemplary embodiment, the boom  40  is a telescopic, articulating boom assembly. By way of example, the lower boom  50  and/or the upper boom  70  may include a plurality of telescoping boom sections that are configured to extend and retract along a longitudinal centerline thereof to selectively increase and decrease a length of the boom  40 . 
     As shown in  FIG.  1   , the lower boom  50  has a first end (e.g., a lower end, etc.), shown as base end  52 , and an opposing second end, shown as intermediate end  54 . The base end  52  of the lower boom  50  is pivotally coupled (e.g., pinned, etc.) to the turntable  14  at a joint, shown as lower boom pivot  56 . As shown in  FIG.  1   , the boom  40  includes a first actuator (e.g., pneumatic cylinder, electric actuator, hydraulic cylinder, etc.), shown as lower lift cylinder  60 . The lower lift cylinder  60  has a first end coupled to the turntable  14  and an opposing second end coupled to the lower boom  50 . According to an exemplary embodiment, the lower lift cylinder  60  is positioned to raise and lower the lower boom  50  relative to the turntable  14  about the lower boom pivot  56 . 
     As shown in  FIG.  1   , the upper boom  70  has a first end, shown as intermediate end  72 , and an opposing second end, shown as implement end  74 . The intermediate end  72  of the upper boom  70  is pivotally coupled (e.g., pinned, etc.) to the intermediate end  54  of the lower boom  50  at a joint, shown as upper boom pivot  76 . As shown in  FIG.  1   , the boom  40  includes an implement, shown as platform assembly  92 , coupled to the implement end  74  of the upper boom  70  with an extension arm, shown as jib arm  90 . In some embodiments, the jib arm  90  is configured to facilitate pivoting the platform assembly  92  about a lateral axis (e.g., pivot the platform assembly  92  up and down, etc.). In some embodiments, the jib arm  90  is configured to facilitate pivoting the platform assembly  92  about a vertical axis (e.g., pivot the platform assembly  92  left and right, etc.). In some embodiments, the jib arm  90  is configured to facilitate extending and retracting the platform assembly  92  relative to the implement end  74  of the upper boom  70 . As shown in  FIG.  1   , the boom  40  includes a second actuator (e.g., pneumatic cylinder, electric actuator, hydraulic cylinder, etc.), shown as upper lift cylinder  80 . According to an exemplary embodiment, the upper lift cylinder  80  is positioned to actuate (e.g., lift, rotate, elevate, etc.) the upper boom  70  and the platform assembly  92  relative to the lower boom  50  about the upper boom pivot  76 . 
     According to an exemplary embodiment, the platform assembly  92  is a structure that is particularly configured to support one or more workers. In some embodiments, the platform assembly  92  includes an accessory or tool configured for use by a worker. Such tools may include pneumatic tools (e.g., impact wrench, airbrush, nail gun, ratchet, etc.), plasma cutters, welders, spotlights, etc. In some embodiments, the platform assembly  92  includes a control panel to control operation of the lift device  10  (e.g., the turntable  14 , the boom  40 , etc.) from the platform assembly  92 . In other embodiments, the platform assembly  92  includes or is replaced with an accessory and/or tool (e.g., forklift forks, etc.). 
     As shown in  FIGS.  1 - 15   , the lift device  10  includes a chassis leveling assembly, shown as leveling system  100 . According to an exemplary embodiment, the leveling system  100  is configured to facilitate maintaining the lift base  12 , the turntable  14 , and/or the platform assembly  92  of the lift device  10  level relative to gravity (e.g., while stationary, while being driven on uneven and/or sloped ground, while operating the boom  40 , etc.). As shown in FIGS.  FIGS.  2 - 8  and  10 - 15   , the leveling system  100  includes a first leveling assembly, shown as front right leveling assembly  110 , pivotally coupled to a right side of the front end  20  of the lift base  12 ; a second leveling assembly, shown as front left leveling assembly  130 , pivotally coupled to a left side of the front end  20  of the lift base  12 ; a third leveling assembly, shown as rear right leveling assembly  150 , pivotally coupled to the right side of the rear end  30  of the lift base  12 ; and a fourth leveling assembly, shown as rear left leveling assembly  170 , pivotally coupled to the left side of the rear end  30  of the lift base  12 . According to an exemplary embodiment, the front right leveling assembly  110 , the front left leveling assembly  130 , the rear right leveling assembly  150 , and the rear left leveling assembly  170  facilitate providing two degrees of movement (e.g., pitch and roll adjustment, etc.) of the front end  20  and the rear end  30  of the lift base  12 . 
     As shown in  FIGS.  9 - 13 ,  18 ,  19 , and  22   , the lift base  12  includes a first plate, shown as front plate  13 ; a second plate, shown as rear plate  15 , spaced from the front plate  13 ; a third plate shown as right side plate  17 , extending between the front plate  13  and the rear plate  15  along the right edges thereof; a fourth plate, shown as left side plate  19 , spaced from the right side plate  17  and extending between the front plate  13  and the rear plate  15  along the left edges thereof; a fifth plate, shown as top plate  21 , extending between the top edges of the front plate  13 , the rear plate  15 , the right side plate  17 , and the left side plate  19 ; and a sixth plate, shown as bottom plate  23 , spaced from the top plate  21  and extending between the bottom edges of the front plate  13 , the rear plate  15 , the right side plate  17 , and the left side plate  19 . As shown in  FIGS.  9  and  22   , the front plate  13 , the rear plate  15 , the right side plate  17 , the left side plate  19 , the top plate  21 , and the bottom plate  23  cooperatively define an internal cavity of the lift base  12 , shown as interior chamber  25 . As shown in  FIGS.  9 ,  10 ,  18 , and  19   , the right side plate  17  and the left side plate  19  each define openings, shown as access ports  27 , that provide selective access to components positioned within the interior chamber  25  (e.g., electronics, hydraulic circuitry, etc.) and facilitate easier assembly and service. In other embodiments, only one of the right side plate  17  or the left side plate  19  defines an access port  27 . As shown in  FIGS.  10 ,  18 , and  19   , the lift base  12  includes panels, shown as doors  29 , that are detachably coupled to the right side plate  17  and the left side plate  19  to selectively enclose the access ports  27  and facilitate selectively accessing the interior chamber  25 . 
     As shown in  FIGS.  2 - 6  and  9   , the lift base  12  includes a first coupler, shown as upper right pivot  22 , coupled to the upper right portion of the front end  20  of the lift base  12 ; a second coupler, shown as upper left pivot  24 , coupled to the upper left portion of the front end  20  of the lift base  12 ; a third coupler, shown as lower right pivot  26 , coupled to the lower right portion of the front end  20  of the lift base  12 ; and a fourth coupler, shown as lower left pivot  28 , coupled to the lower left portion of the front end  20  of the lift base  12 . According to an exemplary embodiment, (i) the upper right pivot  22  and the lower right pivot  26  are at least partially formed by the right side plate  17 , (ii) the upper left pivot  24  and the lower left pivot  28  are at least partially formed by the left side plate  19 , and (iii) the upper right pivot  22 , upper left pivot  24 , the lower right pivot  26 , and the lower left pivot  28  extend from the front plate  13 . As shown in  FIGS.  2 - 5 ,  7 , and  9   , the lift base  12  includes a fifth coupler, shown as upper right pivot  32 , coupled to the upper right portion of the rear end  30  of the lift base  12 ; a sixth coupler, shown as upper left pivot  34 , coupled to the upper left portion of the rear end  30  of the lift base  12 ; a seventh coupler, shown as lower right pivot  36 , coupled to the lower right portion of the rear end  30  of the lift base  12 ; and an eighth coupler, shown as lower left pivot  38 , coupled to the lower left portion of the rear end  30  of the lift base  12 . According to an exemplary embodiment, (i) the upper right pivot  32  and the lower right pivot  36  are at least partially formed by the right side plate  17 , (ii) the upper left pivot  34  and the lower left pivot  38  are at least partially formed by the left side plate  19 , and (iii) the upper right pivot  32 , upper left pivot  34 , the lower right pivot  36 , and the lower left pivot  38  extend from the rear plate  15 . 
     As shown in  FIGS.  2 ,  3 ,  5 ,  6 ,  8 , and  10 - 15   , the front right leveling assembly  110  includes a first arm, shown as front right trailing arm  111 , having a first portion, shown as longitudinal member  112 , and a second portion, shown as lateral member  114 , extending from the longitudinal member  112 . According to an exemplary embodiment, the lateral member  114  extends at an angle substantially perpendicular to the longitudinal member  112  (e.g., such that the front right trailing arm  111  is “L-shaped,” etc.). In other embodiments, the lateral member  114  extends at an angle that is obtuse (e.g., greater than ninety degrees, etc.) to the longitudinal member  112 . According to an exemplary embodiment, the longitudinal member  112  and the lateral member  114  are integrally formed or otherwise permanently coupled to each other (e.g., welded, etc.) such that the front right trailing arm  111  has a unitary structure. In other embodiments, the longitudinal member  112  and the lateral member  114  are fastened together (e.g., using bolts, etc.). 
     As shown in  FIGS.  2 ,  3 ,  5 ,  6 ,  8 , and  10 - 15   , the front right trailing arm  111  includes (i) a first coupler, shown as base coupler  116 , positioned at a free end of the longitudinal member  112  and (ii) a second coupler, shown as tractive element coupler  118 , positioned at a free end of the lateral member  114 . As shown in  FIG.  5   , the base coupler  116  is configured to interface with the lower right pivot  26  to pivotally couple the front right trailing arm  111  to the front end  20  of the lift base  12 . As shown in  FIGS.  2 ,  3 ,  6 , and  11 - 15   , the tractive element coupler  118  is configured to interface with a respective one of the drive actuators  18  such that the respective one of the drive actuators  18  and the tractive element  16  corresponding therewith (e.g., coupled thereto, driven thereby, etc.) is pivotally coupled (e.g., pinned, about a vertical axis defined by the pivot point, etc.) to the lateral member  114  of the front right trailing arm  111 . 
     As shown in  FIGS.  2 ,  3 ,  6 ,  8 , and  10 - 15   , the front right trailing arm  111  includes (i) a third coupler, shown as leveling actuator coupler  120 , positioned along an interior edge/surface of the front right trailing arm  111  proximate the interface between the longitudinal member  112  and the lateral member  114  and (ii) a fourth coupler, shown as steering actuator coupler  122 , positioned along an exterior edge/surface of the lateral member  114  of the front right trailing arm  111 . As shown in  FIGS.  2 ,  3 ,  5 ,  6 ,  8 , and  11 - 13   , the front right leveling assembly  110  includes a first leveling actuator, shown as front right leveling actuator  200 , having (i) a first end, shown as base end  202 , pivotally coupled to the upper right pivot  22  of the lift base  12  and (ii) an opposing second end, shown as arm end  204 , pivotally coupled to the leveling actuator coupler  120  of the front right trailing arm  111 . According to an exemplary embodiment, the front right leveling actuator  200  is positioned to facilitate independently and selectively pivoting the front right trailing arm  111  relative to the front end  20  of the lift base  12  about the lower right pivot  26  (e.g., about a lateral axis defined thereby, etc.). According to an exemplary embodiment, the front right leveling actuator  200  is or includes a hydraulic cylinder. In other embodiments, the front right leveling actuator  200  is or includes another type of actuator (e.g., a pneumatic cylinder, an electric actuator, etc.). 
     As shown in  FIGS.  2 ,  3 ,  6 , and  12 - 15   , the front right leveling assembly  110  includes a first steering actuator, shown as front right steering actuator  210 , having (i) a first end, shown as first end  212 , pivotally coupled to the steering actuator coupler  122  of the front right trailing arm  111  and (ii) an opposing second end, shown as second end  214 , pivotally coupled to a respective one of the drive actuators  18  (e.g., a front right drive actuator, etc.). According to an exemplary embodiment, the front right steering actuator  210  is positioned to facilitate independently and selectively pivoting (i.e., steering) the respective one of the drive actuators  18  and the tractive element  16  corresponding therewith relative to the front right trailing arm  111  about the tractive element coupler  118  (e.g., about a vertical axis defined thereby, etc.). According to an exemplary embodiment, the front right steering actuator  210  is or includes a hydraulic cylinder. In other embodiments, the front right steering actuator  210  is or includes another type of actuator (e.g., a pneumatic cylinder, an electric actuator, etc.). 
     As shown in  FIGS.  2 - 4 ,  6 ,  8 , and  10 - 15   , the front left leveling assembly  130  includes a second arm, shown as front left trailing arm  131 , having a first portion, shown as longitudinal member  132 , and a second portion, shown as lateral member  134 , extending from the longitudinal member  132 . According to an exemplary embodiment, the lateral member  134  extends at an angle substantially perpendicular to the longitudinal member  132  (e.g., such that the front left trailing arm  131  is “L-shaped,” etc.). In other embodiments, the lateral member  134  extends at an angle that is obtuse (e.g., greater than ninety degrees, etc.) to the longitudinal member  132 . According to an exemplary embodiment, the longitudinal member  132  and the lateral member  134  are integrally formed or otherwise permanently coupled to each other (e.g., welded, etc.) such that the front left trailing arm  131  has a unitary structure. In other embodiments, the longitudinal member  132  and the lateral member  134  are fastened together (e.g., using bolts, etc.). 
     As shown in  FIGS.  2 - 4 ,  6 ,  8 , and  10 - 15   , the front left trailing arm  131  includes (i) a first coupler, shown as base coupler  136 , positioned at a free end of the longitudinal member  132  and (ii) a second coupler, shown as tractive element coupler  138 , positioned at a free end of the lateral member  134 . As shown in  FIG.  4   , the base coupler  136  is configured to interface with the lower left pivot  28  to pivotally couple the front left trailing arm  131  to the front end  20  of the lift base  12 . As shown in  FIGS.  3 ,  6 , and  11 - 15   , the tractive element coupler  138  is configured to interface with a respective one of the drive actuators  18  such that the respective one of the drive actuators  18  and the tractive element  16  corresponding therewith (e.g., coupled thereto, driven thereby, etc.) is pivotally coupled (e.g., pinned, about a vertical axis defined by the pivot point, etc.) to the lateral member  134  of the front left trailing arm  131 . 
     As shown in  FIGS.  2 ,  3 ,  6 ,  8 , and  10 - 15   , the front left trailing arm  131  includes (i) a third coupler, shown as leveling actuator coupler  140 , positioned along an interior edge/surface of the front left trailing arm  131  proximate the interface between the longitudinal member  132  and the lateral member  134  and (ii) a fourth coupler, shown as steering actuator coupler  142 , positioned along an exterior edge/surface of the lateral member  134  of the front left trailing arm  131 . As shown in  FIGS.  2 - 4 ,  6 ,  8 , and  11 - 13   , the front left leveling assembly  130  includes a second leveling actuator, shown as front left leveling actuator  220 , having (i) a first end, shown as base end  222 , pivotally coupled to the upper left pivot  24  of the lift base  12  and (ii) an opposing second end, shown as arm end  224 , pivotally coupled to the leveling actuator coupler  140  of the front left trailing arm  131 . According to an exemplary embodiment, the front left leveling actuator  220  is positioned to facilitate independently and selectively pivoting the front left trailing arm  131  relative to the front end  20  of the lift base  12  about the lower left pivot  28  (e.g., about a lateral axis defined thereby, etc.). According to an exemplary embodiment, the front left leveling actuator  220  is or includes a hydraulic cylinder. In other embodiments, the front left leveling actuator  220  is or includes another type of actuator (e.g., a pneumatic cylinder, an electric actuator, etc.). 
     As shown in  FIGS.  2 ,  3 ,  6 , and  12 - 15   , the front left leveling assembly  130  includes a second steering actuator, shown as front left steering actuator  230 , having (i) a first end, shown as first end  232 , pivotally coupled to the steering actuator coupler  142  of the front left trailing arm  131  and (ii) an opposing second end, shown as second end  234 , pivotally coupled to a respective one of the drive actuators  18  (e.g., a front left drive actuator, etc.). According to an exemplary embodiment, the front left steering actuator  230  is positioned to facilitate independently and selectively pivoting (i.e., steering) the respective one of the drive actuators  18  and the tractive element  16  corresponding therewith relative to the front left trailing arm  131  about the tractive element coupler  138  (e.g., about a vertical axis defined thereby, etc.). According to an exemplary embodiment, the front left steering actuator  230  is or includes a hydraulic cylinder. In other embodiments, the front left steering actuator  230  is or includes another type of actuator (e.g., a pneumatic cylinder, an electric actuator, etc.). 
     As shown in  FIGS.  3 ,  5 ,  7 , and  10 - 13   , the rear right leveling assembly  150  includes a third arm, shown as rear right trailing arm  151 , having a first portion, shown as longitudinal member  152 , and a second portion, shown as lateral member  154 , extending from the longitudinal member  152 . According to an exemplary embodiment, the lateral member  154  extends at an angle substantially perpendicular to the longitudinal member  152  (e.g., such that the rear right trailing arm  151  is “L-shaped,” etc.). In other embodiments, the lateral member  154  extends at an angle that is obtuse (e.g., greater than ninety degrees, etc.) to the longitudinal member  152 . According to an exemplary embodiment, the longitudinal member  152  and the lateral member  154  are integrally formed or otherwise permanently coupled to each other (e.g., welded, etc.) such that the rear right trailing arm  151  has a unitary structure. In other embodiments, the longitudinal member  152  and the lateral member  154  are fastened together (e.g., using bolts, etc.). 
     As shown in  FIGS.  3 ,  5 ,  7 ,  8 , and  10 - 13   , the rear right trailing arm  151  includes (i) a first coupler, shown as base coupler  156 , positioned at a free end of the longitudinal member  152  and (ii) a second coupler, shown as tractive element coupler  158 , positioned at a free end of the lateral member  154 . As shown in  FIG.  5   , the base coupler  156  is configured to interface with the lower right pivot  36  to pivotally couple the rear right trailing arm  151  to the rear end  30  of the lift base  12 . As shown in  FIGS.  3 ,  7 ,  8 ,  10 , and  11   , the tractive element coupler  158  is configured to interface with a respective one of the tractive elements  16  (e.g., a rear right tractive element, etc.) such that the orientation of the respective one of the tractive elements  16  is fixed (e.g., non-steerable, etc.). As shown in  FIGS.  12  and  13   , the tractive element coupler  158  is alternatively configured to interface with a respective one of the drive actuators  18  such that the respective one of the drive actuators  18  and the tractive element  16  corresponding therewith (e.g., coupled thereto, driven thereby, etc.) is pivotally coupled (e.g., pinned, about a vertical axis defined by the pivot point, etc.) to the lateral member  154  of the rear right trailing arm  151 . 
     As shown in  FIGS.  3 ,  8 , and  10 - 13   , the rear right trailing arm  151  includes a third coupler, shown as leveling actuator coupler  160 , positioned along an interior edge/surface of the rear right trailing arm  151  proximate the interface between the longitudinal member  152  and the lateral member  154 . As shown in  FIGS.  3 ,  5 ,  7 ,  8 , and  11 - 13   , the rear right leveling assembly  150  includes a third leveling actuator, shown as rear right leveling actuator  240 , having (i) a first end, shown as base end  242 , pivotally coupled to the upper right pivot  32  of the lift base  12  and (ii) an opposing second end, shown as arm end  244 , pivotally coupled to the leveling actuator coupler  160  of the rear right trailing arm  151 . According to an exemplary embodiment, the rear right leveling actuator  240  is positioned to facilitate independently and selectively pivoting the rear right trailing arm  151  relative to the rear end  30  of the lift base  12  about the lower right pivot  36  (e.g., about a lateral axis defined thereby, etc.). According to an exemplary embodiment, the rear right leveling actuator  240  is or includes a hydraulic cylinder. In other embodiments, the rear right leveling actuator  240  is or includes another type of actuator (e.g., a pneumatic cylinder, an electric actuator, etc.). 
     As shown in  FIGS.  12  and  13   , the rear right trailing arm  151  includes a fourth coupler, shown as steering actuator coupler  162 , positioned along an exterior edge/surface of the lateral member  154  of the rear right trailing arm  151 . As shown in  FIGS.  12  and  13   , the rear right leveling assembly  150  includes a third steering actuator, shown as rear right steering actuator  250 , having (i) a first end pivotally coupled to the steering actuator coupler  162  of the rear right trailing arm  151  and (ii) an opposing second end pivotally coupled to a respective one of the drive actuators  18  (e.g., a rear right drive actuator, etc.). According to an exemplary embodiment, the rear right steering actuator  250  is positioned to facilitate independently and selectively pivoting (i.e., steering) the respective one of the drive actuators  18  and the tractive element  16  corresponding therewith relative to the rear right trailing arm  151  about the tractive element coupler  158  (e.g., about a vertical axis defined thereby, etc.). According to an exemplary embodiment, the rear right steering actuator  250  is or includes a hydraulic cylinder. In other embodiments, the rear right steering actuator  250  is or includes another type of actuator (e.g., a pneumatic cylinder, an electric actuator, etc.). 
     As shown in  FIGS.  2 - 4 ,  7 ,  8 , and  10 - 13   , the rear left leveling assembly  170  includes a fourth arm, shown as rear left trailing arm  171 , having a first portion, shown as longitudinal member  172 , and a second portion, shown as lateral member  174 , extending from the longitudinal member  172 . According to an exemplary embodiment, the lateral member  174  extends at an angle substantially perpendicular to the longitudinal member  172  (e.g., such that the rear left trailing arm  171  is “L-shaped,” etc.). In other embodiments, the lateral member  174  extends at an angle that is obtuse (e.g., greater than ninety degrees, etc.) to the longitudinal member  172 . According to an exemplary embodiment, the longitudinal member  172  and the lateral member  174  are integrally formed or otherwise permanently coupled to each other (e.g., welded, etc.) such that the rear left trailing arm  171  has a unitary structure. In other embodiments, the longitudinal member  172  and the lateral member  174  are fastened together (e.g., using bolts, etc.). 
     As shown in  FIGS.  2 - 4 ,  7 ,  8 , and  10 - 13   , the rear left trailing arm  171  includes (i) a first coupler, shown as base coupler  176 , positioned at a free end of the longitudinal member  172  and (ii) a second coupler, shown as tractive element coupler  178 , positioned at a free end of the lateral member  174 . As shown in  FIGS.  2  and  4   , the base coupler  176  is configured to interface with the lower left pivot  38  to pivotally couple the rear left trailing arm  171  to the rear end  30  of the lift base  12 . As shown in  FIGS.  3 ,  7 ,  8 ,  10 , and  11   , the tractive element coupler  178  is configured to interface with a respective one of the tractive elements  16  (e.g., a rear left tractive element, etc.) such that the orientation of the respective one of the tractive elements  16  is fixed (e.g., non-steerable, etc.). As shown in  FIGS.  12  and  13   , the tractive element coupler  178  is alternatively configured to interface with a respective one of the drive actuators  18  such that the respective one of the drive actuators  18  and the tractive element  16  corresponding therewith (e.g., coupled thereto, driven thereby, etc.) is pivotally coupled (e.g., pinned, about a vertical axis defined by the pivot point, etc.) to the lateral member  174  of the rear left trailing arm  171 . 
     As shown in  FIGS.  2 ,  3 , and  10 - 13   , the rear left trailing arm  171  includes a third coupler, shown as leveling actuator coupler  180 , positioned along an interior edge/surface of the rear left trailing arm  171  proximate the interface between the longitudinal member  172  and the lateral member  154 . As shown in  FIGS.  2 - 4 ,  7 ,  8 , and  11 - 13   , the rear left leveling assembly  170  includes a fourth leveling actuator, shown as rear left leveling actuator  260 , having (i) a first end, shown as base end  262 , pivotally coupled to the upper left pivot  34  of the lift base  12  and (ii) an opposing second end, shown as arm end  264 , pivotally coupled to the leveling actuator coupler  180  of the rear left trailing arm  171 . According to an exemplary embodiment, the rear left leveling actuator  260  is positioned to facilitate independently and selectively pivoting the rear left trailing arm  171  relative to the rear end  30  of the lift base  12  about the lower left pivot  38  (e.g., about a lateral axis defined thereby, etc.). According to an exemplary embodiment, the rear left leveling actuator  260  is or includes a hydraulic cylinder. In other embodiments, the rear left leveling actuator  260  is or includes another type of actuator (e.g., a pneumatic cylinder, an electric actuator, etc.). 
     As shown in  FIGS.  12  and  13   , the rear left trailing arm  171  includes a fourth coupler, shown as steering actuator coupler  182 , positioned along an exterior edge/surface of the lateral member  174  of the rear left trailing arm  171 . As shown in  FIGS.  12  and  13   , the rear left leveling assembly  170  includes a fourth steering actuator, shown as rear left steering actuator  270 , having (i) a first end pivotally coupled to the steering actuator coupler  182  of the rear left trailing arm  171  and (ii) an opposing second end pivotally coupled to a respective one of the drive actuators  18  (e.g., a rear left drive actuator, etc.). According to an exemplary embodiment, the rear left steering actuator  270  is positioned to facilitate independently and selectively pivoting (i.e., steering) the respective one of the drive actuators  18  and the tractive element  16  corresponding therewith relative to the rear left trailing arm  171  about the tractive element coupler  178  (e.g., about a vertical axis defined thereby, etc.). According to an exemplary embodiment, the rear left steering actuator  270  is or includes a hydraulic cylinder. In other embodiments, the rear left steering actuator  270  is or includes another type of actuator (e.g., a pneumatic cylinder, an electric actuator, etc.). 
     According to the exemplary embodiment shown in  FIGS.  2 ,  3 ,  6 ,  7 , and  11   , the front right steering actuator  210  and the front left steering actuator  230  facilitate providing two-wheel steering. In such an embodiment, the rear right trailing arm  151  and the rear left trailing arm  171  may have a different shape than the front right trailing arm  111  and the front left trailing arm  131  (e.g., due to having a non-steerable tractive element, etc.). According to the exemplary embodiment shown in  FIGS.  12  and  13   , the front right steering actuator  210 , the front left steering actuator  230 , the rear right steering actuator  250 , and the rear left steering actuator  270  facilitate providing four-wheel steering. In such an embodiment, the rear right trailing arm  151  and the rear left trailing arm  171  may have the same or substantially the same shape as the front right trailing arm  111  and the front left trailing arm  131  such that the rear trailing arms and the front trailing arms are interchangeable. In other embodiments, the lift device  10  does not include the front right steering actuator  210 , the front left steering actuator  230 , the rear right steering actuator  250 , and the rear left steering actuator  270 . In such embodiments, the direction of the lift device  10  may be controlled using skid steering. 
     As shown in  FIGS.  8  and  10 - 15   , the front right trailing arm  111  includes a first angled portion, shown as angled plate  124 , disposed along the bottom of the lateral member  114  and that has a first extension, shown as angled projection  126 , extending forward of the lateral member  114  and past the front right steering actuator  210 . As shown in  FIGS.  8  and  10 - 15   , the front left trailing arm  131  includes a second angled portion, shown as angled plate  144 , disposed along the bottom of the lateral member  134  and that has a second extension, shown as angled projection  146 , extending forward of the lateral member  134  and past the front left steering actuator  230 . As shown in  FIG.  10   , the rear right trailing arm  151  includes a third angled portion, shown as angled plate  164 , disposed along the bottom of the lateral member  154 . In some embodiments, as shown in  FIGS.  12  and  13   , the angled plate  164  has a third extension, shown as angled projection  166 , extending forward of the lateral member  154  and past the rear right steering actuator  250 . As shown in  FIG.  10   , the rear left trailing arm  171  includes a fourth angled portion, shown as angled plate  184 , disposed along the bottom of the lateral member  174 . In some embodiments, as shown in  FIGS.  12  and  13   , the angled plate  184  has a fourth extension, shown as angled projection  186 , extending forward of the lateral member  174  and past the rear left steering actuator  270 . 
     According to an exemplary embodiment, the angled projection  126 , the angled projection  146 , the angled projection  166 , and the angled projection  186  are configured (e.g., positioned, shaped, etc.) to protect the front right steering actuator  210 , the front left steering actuator  230 , the rear right steering actuator  250 , and the rear left steering actuator  270 , respectively. According to an exemplary embodiment, the angled plate  124 , the angled plate  144 , the angled plate  164 , and the angled plate  184  are configured (e.g., positioned, shaped, etc.) to improve ground clearance of the lift base  12 . According to an exemplary embodiment, the shape of the front right trailing arm  111 , the front left trailing arm  131 , the rear right trailing arm  151 , and the rear left trailing arm  171  provide about eight inches of ground clearance while the lift device  10  is on a ten-degree side slope. 
     According to an exemplary embodiment, the front right trailing arm  111 , the front left trailing arm  131 , the rear right trailing arm  151 , and the rear left trailing arm  171  are shaped to optimize the stroke of the front right leveling actuator  200 , the front left leveling actuator  220 , the rear right leveling actuator  240 , and the rear left leveling actuator  260 . One example of such optimization is shown in  FIG.  19   . Specifically, as shown in  FIG.  19   , the front right trailing arm  111 , the front left trailing arm  131 , the rear right trailing arm  151 , and the rear left trailing arm  171  are shaped such that (i) the front right leveling actuator  200 , the front left leveling actuator  220 , the rear right leveling actuator  240 , and the rear left leveling actuator  260  may be fully retracted and (ii) the front right trailing arm  111 , the front left trailing arm  131 , the rear right trailing arm  151 , and the rear left trailing arm  171  may pivot sufficiently to provide a minimum ground clearance h between the bottom plate  23  of the lift base  12  and a ground surface. According to an exemplary embodiment, the minimum ground clearance h is three inches or less (e.g., 3, 2.75, 2.5, 2.25 2, 1.5, 1.25, 1, 0.75, 0.5, etc. inches). According to an exemplary embodiment, the bottom plate  23  is a solid plate manufactured from a metal material (e.g., steel, etc.). Such a solid plate provides increased protection by preventing ingress and damage to the internals of the lift base  12 . 
     As shown in  FIGS.  9  and  22 - 24   , the front plate  13  and the rear plate  15  of the lift base  12  each include a plurality of routing features, shown as routing features  31 . As shown in  FIGS.  22 - 24   , each of the routing features  31  defines an aperture, shown as through-hole  33 , and includes an extension plate, shown as tab  35 , (i) positioned at the bottom of the through-hole  33  and (ii) extending from the front plate  13  or the rear plate  15  into the interior chamber  25  of the lift base  12 . As shown in  FIGS.  23  and  24   , the through-holes  33  of the routing features  31  are configured to facilitate passing hosing and/or wiring, shown as hosing and/or wiring  37 , from the interior chamber  25  of the lift base  12  through the front plate  13  and/or the rear plate  15  to various components of the lift device  10  positioned outside of the lift base  12  (e.g., the drive actuators  18 , the front right leveling actuator  200 , the front right steering actuator  210 , the front left leveling actuator  220 , the front left steering actuator  230 , the rear right leveling actuator  240 , the rear right steering actuator  250 , the rear left leveling actuator  260 , the rear left steering actuator  270 , sensors, etc.). The hosing and/or wiring  37  may include hosing for a hydraulic circuit to facilitate the operation of hydraulically-operated components of the lift device  10 , hosing for a pneumatic circuit to facilitate the operation of pneumatically-operated components of the lift device  10 , and/or electrical wiring to facilitate the operation of electrically-operated components of the lift device  10  (e.g., for the actuator circuit  300 , etc.). As shown in  FIGS.  23    and  24 , a plurality of individual hoses and/or wiring of the hoses and/or wiring  37  lie on the tabs  35  and the tabs  35  facilitate selectively retaining the plurality of individual hoses and/or wiring of the hosing and/or wiring  37  together using a retaining element, shown as retainer  39 . As shown in  FIG.  22   , each of the tabs  35  defines indents, shown as notches  41 , along the edges thereof to prevent the retainer  39  from sliding off of the tabs  35 . The retainer  39  may include a strap, a Velcro strap, an elastic band, a zip-tie and/or still another suitable retaining element to secure the hosing and/or wiring  37  to the tabs  35 . 
     According to an exemplary embodiment, the front right steering actuator  210 , the front left steering actuator  230 , the rear right steering actuator  250 , and the rear left steering actuator  270  each have separate inputs (e.g., hydraulic inputs, etc.) to facilitate precise steer geometry control. As shown in  FIGS.  14 - 17   , the lift device  10  includes a plurality of steering sensors, shown as steering sensors  280 . As shown in  FIG.  17   , each of the steering sensors  280  is positioned atop a respective pin, shown as kingpin  42 , that pivotally couples one of the drive actuators  18  to one of the tractive element coupler  118  of the front right trailing arm  111 , the tractive element coupler  138  of the front left trailing arm  131 , the tractive element coupler  158  of the rear right trailing arm  151 , and the tractive element coupler  178  of the rear left trailing arm  171  about a pivot axis, shown as steer axis  44 . According to an exemplary embodiment, the steering sensors  280  are configured to acquire steering data to facilitate monitoring the current position (e.g., rotation angle about the steer axis  44 , etc.) of each of the tractive elements  16 . As shown in  FIGS.  16  and  17   , each of the steering sensors  280  includes a body, shown as sensor body  282 , that remains stationary at the center of the kingpin  42 ; a spindle, shown as spindle  284 , coupled to the top of the kingpin  42  and rotates therewith about the steer axis  44 ; an extension, shown as boss  286 , extending from the spindle  284 ; and an arm, shown as rotary arm  288 , affixed to the spindle  284  and held captive by the boss  286 . According to an exemplary embodiment, the rotary arm  288  includes an internal spring and sensor shaft disposed therein. The internal spring is positioned to bias the sensor shaft within the boss  286  to ensure constant contact therewith and output. 
     As shown in  FIGS.  18 - 21   , each of the front right leveling actuator  200 , the front left leveling actuator  220 , the rear right leveling actuator  240 , and the rear left leveling actuator  260  includes a pressure sensor assembly, shown as pressure sensor assembly  290 . As shown in  FIG.  20   , each of the pressure sensor assemblies  290  includes (i) a first block, shown as pressure sensor mounting block  292 , configured to couple to a first end of the cylinder of a respective one of the front right leveling actuator  200 , the front left leveling actuator  220 , the rear right leveling actuator  240 , and the rear left leveling actuator  260  and (ii) a second block, shown as pressure sensor mounting block  294 , configured to couple to an opposing second end of the cylinder of the respective one of the front right leveling actuator  200 , the front left leveling actuator  220 , the rear right leveling actuator  240 , and the rear left leveling actuator  260 . According to an exemplary embodiment, the pressure sensor mounting block  292  and the pressure sensor mounting block  294  are configured to facilitate coupling one or more pressure sensors (e.g., the load sensors  408 , etc.) to the corresponding leveling actuator to facilitate acquiring pressure data regarding a bore side pressure and/or a rod side pressure within each of the front right leveling actuator  200 , the front left leveling actuator  220 , the rear right leveling actuator  240 , and the rear left leveling actuator  260 . In some embodiments, the pressure sensor mounting block  292  and/or the pressure sensor mounting block  294  are configured to each facilitate coupling a plurality of pressure sensors (e.g., two each, etc.) to the corresponding leveling actuator (e.g., for a total of four or more pressure sensors per leveling actuator, etc.). 
     As shown in  FIGS.  18 ,  19 , and  21   , each of the pressure sensor assemblies  290  includes a cover, shown as cap  296 . According to exemplary embodiment, each of the caps  296  ( i ) selectively couples (e.g., via fasteners, a snap fit, etc.) to the pressure sensor mounting block  292  and the pressure sensor mounting block  294  of a respective leveling actuator and (ii) extends along the cylinder of the respective leveling actuator to provide protection for the pressure sensors and/or the cylinder. 
     As shown in  FIGS.  1  and  2   , the lift device  10  includes an actuator circuit, shown as actuator circuit  300 , and a control system, shown as lift device control system  400 . According to an exemplary embodiment, the actuator circuit  300  includes a hydraulic circuit configured to facilitate operating (e.g., driving the extension and/or retraction of, etc.) the front right leveling actuator  200 , the front right steering actuator  210 , the front left leveling actuator  220 , the front left steering actuator  230 , the rear right leveling actuator  240 , the rear right steering actuator  250 , the rear left leveling actuator  260 , the rear left steering actuator  270 , and/or the drive actuators  18  (e.g., in embodiments where one or more of the respective actuators include hydraulic cylinders, etc.). In other embodiments, the actuator circuit  300  additionally or alternatively includes an electric circuit (e.g., in embodiments where one or more of the actuators include electric actuators, etc.) and/or a pneumatic circuit (e.g., in embodiments where one or more of the actuators include pneumatic cylinders, etc.). According to an exemplary embodiment, the lift device control system  400  is configured to control the operation of the actuator circuit  300  and thereby control the front right leveling actuator  200 , the front right steering actuator  210 , the front left leveling actuator  220 , the front left steering actuator  230 , the rear right leveling actuator  240 , the rear right steering actuator  250 , the rear left leveling actuator  260 , the rear left steering actuator  270 , and/or the drive actuators  18  (e.g., the extension and/or retraction thereof; pitch, roll, and/or height adjustment of the lift base  12 ; etc.). 
     According to the exemplary embodiment shown in  FIGS.  25  and  30   , the actuator circuit  300  includes the front right leveling actuator  200 , the front right steering actuator  210 , the front left leveling actuator  220 , the front left steering actuator  230 , the rear right leveling actuator  240 , and the rear left leveling actuator  260 . In some embodiments, the actuator circuit  300  additionally includes the rear right steering actuator  250  and the rear left steering actuator  270 . As shown in  FIGS.  25  and  30   , the actuator circuit  300  further includes a first leveling module, shown as front right leveling module  310 , a first float module, shown as front right float module  312 , a second leveling module, shown as front left leveling module  330 , a second float module, shown as front left float module  332 , a third leveling module, shown as rear right leveling module  350 , a third float module, shown as rear right float module  352 , a fourth leveling module, shown as rear left leveling module  370 , a fourth float module, shown as rear left float module  372 , a first steering module, shown as front right steering module  380 , and a second steering module, shown as front left steering module  382 . In some embodiments (e.g., embodiments where the actuator circuit  300  includes the rear right steering actuator  250  and the rear left steering actuator  270 , etc.), as shown in  FIG.  30   , the actuator circuit  300  additionally includes a third steering module, shown as rear right steering module  384 , and a fourth steering module, shown as rear left steering module  386 . 
     As shown in  FIG.  25   , the front right leveling module  310  (e.g., a valve, a valve assembly, etc.) is associated with and fluidly coupled to the front right leveling actuator  200 . According to an exemplary embodiment, the front right leveling module  310  is fluidly coupled to a fluid source (e.g., a hydraulic tank, a hydraulic pump, etc.) and configured to facilitate an extension and retraction operation of the front right leveling actuator  200  (e.g., by providing hydraulic fluid to or releasing hydraulic fluid from the front right leveling actuator  200 , etc.). The front right leveling module  310  therefore facilitates actively and selectively pivoting the front right trailing arm  111  associated with the front right leveling actuator  200  about the lower right pivot  26 . As shown in  FIG.  25   , the front left leveling module  330  (e.g., a valve, a valve assembly, etc.) is associated with and fluidly coupled to the front left leveling actuator  220 . According to an exemplary embodiment, the front left leveling module  330  is fluidly coupled to the fluid source and configured to facilitate an extension and retraction operation of the front left leveling actuator  220  (e.g., by providing hydraulic fluid to or releasing hydraulic fluid from the front left leveling actuator  220 , etc.). The front left leveling module  330  therefore facilitates actively and selectively pivoting the front left trailing arm  131  associated with the front left leveling actuator  220  about the lower left pivot  28 . 
     As shown in  FIG.  25   , the rear right leveling module  350  (e.g., a valve, a valve assembly, etc.) is associated with and fluidly coupled to the rear right leveling actuator  240 . According to an exemplary embodiment, the rear right leveling module  350  is fluidly coupled to the fluid source and configured to facilitate an extension and retraction operation of the rear right leveling actuator  240  (e.g., by providing hydraulic fluid to or releasing hydraulic fluid from the rear right leveling actuator  240 , etc.). The rear right leveling module  350  therefore facilitates actively and selectively pivoting the rear right trailing arm  151  associated with the rear right leveling actuator  240  about the lower right pivot  36 . As shown in  FIG.  25   , the rear left leveling module  370  (e.g., a valve, a valve assembly, etc.) is associated with and fluidly coupled to the rear left leveling actuator  260 . According to an exemplary embodiment, the rear left leveling module  370  is fluidly coupled to the fluid source and configured to facilitate an extension and retraction operation of the rear left leveling actuator  260  (e.g., by providing hydraulic fluid to or releasing hydraulic fluid from the rear left leveling actuator  260 , etc.). The rear left leveling module  370  therefore facilitates actively and selectively pivoting the rear left trailing arm  171  associated with the rear left leveling actuator  260  about the lower left pivot  38 . 
     As shown in  FIG.  25   , the front right float module  312  includes a first float valve, shown as front right float valve  314 , first float controls (e.g., a valve, a valve assembly, etc.), shown as front right retract float controls  316 , and second float controls (e.g., a valve, a valve assembly, etc.), shown as front right extend float controls  318 . According to an exemplary embodiment, the front right float valve  314  is operable in a first state (e.g., engaged, disengaged, during an active mode, etc.) and a second state (e.g., disengaged, engaged, during a float mode, etc.). In the first state, (i) the front right float valve  314  is configured to fluidly isolate or fluidly decouple the front right leveling actuator  200  from the front left leveling actuator  220 , the rear right leveling actuator  240 , and the rear left leveling actuator  260  and (ii) extension and retraction of the front right leveling actuator  200  is independently and actively controllable (e.g., via the front right leveling module  310 , etc.). In the second state, (i) the front right float valve  314  is configured to fluidly couple the front right leveling actuator  200  to a respective one of the front left leveling actuator  220 , the rear right leveling actuator  240 , and the rear left leveling actuator  260  (e.g., based on which leveling assembly also has a float valve in the second state, etc.) and (ii) extension and retraction of the front right leveling actuator  200  is passively controllable (i.e., the front right leveling actuator  200  freely floats). In some embodiments, the front right float valve  314  is a variable valve (e.g., a proportional valve, etc.) that can be operated in various positions between fully open and fully closed. Such a variable valve may facilitate controlling a rate at which the front right leveling actuator  200  “floats” (e.g., floats quicker if more open than if more closed, etc.). 
     According to an exemplary embodiment, fluidly coupling the front right leveling actuator  200  with a respective one of the other leveling actuators (i.e., the front left leveling actuator  220 , the rear right leveling actuator  240 , or the rear left leveling actuator  260 ) causes the two actuators to emulate the function of a conventional pinned axle where rotation (i.e., roll) occurs freely about a central pin, however, here the central pin is a “virtual pivot point.” According to an exemplary embodiment, the front right retract float controls  316  and the front right extend float controls  318 , independent of or in combination with the float controls associated with the leveling actuator fluidly coupled with the front right leveling actuator  200 , are configured to facilitate selectively removing or adding, respectively, fluid to the fluidly coupled leveling actuators (i.e., the front right leveling actuator  200  and a respective one of the front left leveling actuator  220 , the rear right leveling actuator  240 , and the rear left leveling actuator  260 ) to decrease or increase, respectively, the height of the virtual pivot point of the two fluidly coupled leveling actuators relative to ground by decreasing or increasing, respectively, the volume of fluid flowing between the two fluidly coupled leveling actuators. 
     As shown in  FIG.  25   , the front left float module  332  includes a second float valve, shown as front left float valve  334 , first float controls (e.g., a valve, a valve assembly, etc.), shown as front left retract float controls  336 , and second float controls (e.g., a valve, a valve assembly, etc.), shown as front left extend float controls  338 . According to an exemplary embodiment, the front left float valve  334  is operable in a first state (e.g., engaged, disengaged, during an active mode, etc.) and a second state (e.g., disengaged, engaged, during a float mode, etc.). In the first state, (i) the front left float valve  334  is configured to fluidly isolate or fluidly decouple the front left leveling actuator  220  from the front right leveling actuator  200 , the rear right leveling actuator  240 , and the rear left leveling actuator  260  and (ii) extension and retraction of the front left leveling actuator  220  is independently and actively controllable (e.g., via the front left leveling module  330 , etc.). In the second state, (i) the front left float valve  334  is configured to fluidly couple the front left leveling actuator  220  to a respective one of the front right leveling actuator  200 , the rear right leveling actuator  240 , and the rear left leveling actuator  260  (e.g., based on which leveling assembly also has a float valve in the second state, etc.) and (ii) extension and retraction of the front left leveling actuator  220  is passively controllable (i.e., the front left leveling actuator  220  freely floats). In some embodiments, the front left float valve  334  is a variable valve (e.g., a proportional valve, etc.) that can be operated in various positions between fully open and fully closed. Such a variable valve may facilitate controlling a rate at which the front left leveling actuator  220  “floats” (e.g., floats quicker if more open than if more closed, etc.). 
     According to an exemplary embodiment, fluidly coupling the front left leveling actuator  220  with a respective one of the other leveling actuators (i.e., the front right leveling actuator  200 , the rear right leveling actuator  240 , or the rear left leveling actuator  260 ) causes the two actuators to emulate the function of a conventional pinned axle where rotation (i.e., roll) occurs freely about a central pin, however, here the central pin is a “virtual pivot point.” According to an exemplary embodiment, the front left retract float controls  336  and the front left extend float controls  338 , independent of or in combination with the float controls associated with the leveling actuator fluidly coupled with the front left leveling actuator  220 , are configured to facilitate selectively removing or adding, respectively, fluid to the fluidly coupled leveling actuators (i.e., the front left leveling actuator  220  and a respective one of the front right leveling actuator  200 , the rear right leveling actuator  240 , and the rear left leveling actuator  260 ) to decrease or increase, respectively, the height of the virtual pivot point of the two fluidly coupled leveling actuators relative to ground by decreasing or increasing, respectively, the volume of fluid flowing between the two fluidly coupled leveling actuators. 
     As shown in  FIG.  25   , the rear right float module  352  includes a third float valve, shown as rear right float valve  354 , first float controls (e.g., a valve, a valve assembly, etc.), shown as rear right retract float controls  356 , and second float controls (e.g., a valve, a valve assembly, etc.), shown as rear right extend float controls  358 . According to an exemplary embodiment, the rear right float valve  354  is operable in a first state (e.g., engaged, disengaged, during an active mode, etc.) and a second state (e.g., disengaged, engaged, during a float mode, etc.). In the first state, (i) the rear right float valve  354  is configured to fluidly isolate or fluidly decouple the rear right leveling actuator  240  from the front right leveling actuator  200 , the front left leveling actuator  220 , and the rear left leveling actuator  260  and (ii) extension and retraction of the rear right leveling actuator  240  is independently and actively controllable (e.g., via the rear right leveling module  350 , etc.). In the second state, (i) the rear right float valve  354  is configured to fluidly couple the rear right leveling actuator  240  to a respective one of the front right leveling actuator  200 , the front left leveling actuator  220 , and the rear left leveling actuator  260  (e.g., based on which leveling assembly also has a float valve in the second state, etc.) and (ii) extension and retraction of the rear right leveling actuator  240  is passively controllable (i.e., the rear right leveling actuator  240  freely floats). In some embodiments, the rear right float valve  354  is a variable valve (e.g., a proportional valve, etc.) that can be operated in various positions between fully open and fully closed. Such a variable valve may facilitate controlling a rate at which the rear right leveling actuator  240  “floats” (e.g., floats quicker if more open than if more closed, etc.). 
     According to an exemplary embodiment, fluidly coupling the rear right leveling actuator  240  with a respective one of the other leveling actuators (i.e., the front right leveling actuator  200 , the front left leveling actuator  220 , or the rear left leveling actuator  260 ) causes the two actuators to emulate the function of a conventional pinned axle where rotation (i.e., roll) occurs freely about a central pin, however, here the central pin is a “virtual pivot point.” According to an exemplary embodiment, the rear right retract float controls  356  and the rear right extend float controls  358 , independent of or in combination with the float controls associated with the leveling actuator fluidly coupled with the rear right leveling actuator  240 , are configured to facilitate selectively removing or adding, respectively, fluid to the fluidly coupled leveling actuators (i.e., the rear right leveling actuator  240  and a respective one of the front right leveling actuator  200 , the front left leveling actuator  220 , and the rear left leveling actuator  260 ) to decrease or increase, respectively, the height of the virtual pivot point of the two fluidly coupled leveling actuators relative to ground by decreasing or increasing, respectively, the volume of fluid flowing between the two fluidly coupled leveling actuators. 
     As shown in  FIG.  25   , the rear left float module  372  includes a fourth float valve, shown as rear left float valve  374 , first float controls (e.g., a valve, a valve assembly, etc.), shown as rear left retract float controls  376 , and second float controls (e.g., a valve, a valve assembly, etc.), shown as rear left extend float controls  378 . According to an exemplary embodiment, the rear left float valve  374  is operable in a first state (e.g., engaged, disengaged, during an active mode, etc.) and a second state (e.g., disengaged, engaged, during a float mode, etc.). In the first state, (i) the rear left float valve  374  is configured to fluidly isolate or fluidly decouple the rear left leveling actuator  260  from the front right leveling actuator  200 , the front left leveling actuator  220 , and the rear right leveling actuator  240  and (ii) extension and retraction of the rear left leveling actuator  260  is independently and actively controllable (e.g., via the rear left leveling module  370 , etc.). In the second state, (i) the rear left float valve  374  is configured to fluidly couple the rear left leveling actuator  260  to a respective one of the front right leveling actuator  200 , the front left leveling actuator  220 , and the rear right leveling actuator  240  (e.g., based on which leveling assembly also has a float valve in the second state, etc.) and (ii) extension and retraction of the rear left leveling actuator  260  is passively controllable (i.e., the rear left leveling actuator  260  freely floats). In some embodiments, the rear left float valve  374  is a variable valve (e.g., a proportional valve, etc.) that can be operated in various positions between fully open and fully closed. Such a variable valve may facilitate controlling a rate at which the rear left leveling actuator  260  “floats” (e.g., floats quicker if more open than if more closed, etc.). 
     According to an exemplary embodiment, fluidly coupling the rear left leveling actuator  260  with a respective one of the other leveling actuators (i.e., the front right leveling actuator  200 , the front left leveling actuator  220 , or the rear right leveling actuator  240 ) causes the two actuators to emulate the function of a conventional pinned axle where rotation (i.e., roll) occurs freely about a central pin, however, here the central pin is a “virtual pivot point.” According to an exemplary embodiment, the rear left retract float controls  376  and the rear left extend float controls  378 , independent of or in combination with the float controls associated with the leveling actuator fluidly coupled with the rear left leveling actuator  260 , are configured to facilitate selectively removing or adding, respectively, fluid to the fluidly coupled leveling actuators (i.e., the rear left leveling actuator  260  and a respective one of the front right leveling actuator  200 , the front left leveling actuator  220 , and the rear right leveling actuator  240 ) to decrease or increase, respectively, the height of the virtual pivot point of the two fluidly coupled leveling actuators relative to ground by decreasing or increasing, respectively, the volume of fluid flowing between the two fluidly coupled leveling actuators. 
     As shown in  FIG.  25   , the front right steering module  380  (e.g., a valve, a valve assembly, etc.) is associated with and fluidly coupled to the front right steering actuator  210 . According to an exemplary embodiment, the front right steering module  380  is fluidly coupled to the fluid source and configured to facilitate an extension and retraction operation of the front right steering actuator  210  (e.g., by providing hydraulic fluid to or releasing hydraulic fluid from the front right steering actuator  210 , etc.). The front right steering module  380  therefore facilitates actively and selectively turning the tractive element  16  associated with the front right steering actuator  210 . As shown in  FIG.  25   , the front left steering module  382  (e.g., a valve, a valve assembly, etc.) is associated with and fluidly coupled to the front left steering actuator  230 . According to an exemplary embodiment, the front left steering module  382  is fluidly coupled to the fluid source and configured to facilitate an extension and retraction operation of the front left steering actuator  230  (e.g., by providing hydraulic fluid to or releasing hydraulic fluid from the front left steering actuator  230 , etc.). The front left steering module  390  therefore facilitates actively and selectively turning the tractive element  16  associated with the front left steering actuator  230 . 
     According to an exemplary embodiment, the rear right steering module  384  (e.g., a valve, a valve assembly, etc.) is associated with and fluidly coupled to the rear right steering actuator  250 . According to an exemplary embodiment, the rear right steering module  384  is fluidly coupled to the fluid source and configured to facilitate an extension and retraction operation of the rear right steering actuator  250  (e.g., by providing hydraulic fluid to or releasing hydraulic fluid from the rear right steering actuator  250 , etc.). The rear right steering module  384  therefore facilitates actively and selectively turning the tractive element  16  associated with the rear right steering actuator  250 . According to an exemplary embodiment, the rear left steering module  386  (e.g., a valve, a valve assembly, etc.) is associated with and fluidly coupled to the rear left steering actuator  270 . According to an exemplary embodiment, the rear left steering module  386  is fluidly coupled to the fluid source and configured to facilitate an extension and retraction operation of the rear left steering actuator  270  (e.g., by providing hydraulic fluid to or releasing hydraulic fluid from the rear left steering actuator  270 , etc.). The rear left steering module  386  therefore facilitates actively and selectively turning the tractive element  16  associated with the rear left steering actuator  270 . 
     By way of example, various configurations of the leveling system  100  are shown in  FIGS.  26 - 29   . As shown in  FIG.  26   , the leveling system  100  of the lift device  10  is arranged in a first configuration, shown as rear float configuration  102 . In the rear float configuration  102 , the rear right leveling actuator  240  of the rear right leveling assembly  150  and the rear left leveling actuator  260  of the rear left leveling assembly  170  are selectively fluidly coupled to each other (e.g., by engaging the rear right float valve  354  of the rear right float module  352  and the rear left float valve  374  of the rear left float module  372 , while the front right float valve  314  of the front right float module  312  and the front left float valve  334  of the front left float module  332  remain disengaged, etc.) such that the rear right leveling assembly  150  and the rear left leveling assembly  170  function as if an axle, shown as virtual axle  500 , extends therebetween with a pivot point, shown as virtual pivot point  502 , positioned along and at a center of the virtual axle  500 . The rear float configuration  102  therefore forms a triangle, shown as stability triangle  504 , between the tractive element  16  of the front right leveling assembly  110 , the tractive element  16  of the front left leveling assembly  130 , and the virtual pivot point  502 , rather than a stability rectangle or square between the four tractive elements  16  of the lift device  10 . 
     While the leveling system  100  of the lift device  10  is arranged in the rear float configuration  102 , (i) the rear right leveling assembly  150  and the rear left leveling assembly  170  freely float in response to fluid flowing freely between the rear right leveling actuator  240  and the rear left leveling actuator  260  (i.e., as the rear right leveling actuator  240  extends, the rear left leveling actuator  260  retracts, and vice versa) as the tractive elements  16  thereof encounter the terrain and (ii) the front right leveling actuator  200  of the front right leveling assembly  110  and the front left leveling actuator  220  of the front left leveling assembly  130  are each independently and actively controllable. Further, as the rear right leveling assembly  150  and the rear left leveling assembly  170  freely float while the leveling system  100  of the lift device  10  is arranged in the rear float configuration  102 , the height of the virtual pivot point  502  relative to ground may be selectively adjusted (e.g., increased, decreased, etc.) by manipulating (e.g., increasing, decreasing, etc.) the volume of fluid flowing between the rear right leveling actuator  240  and the rear left leveling actuator  260  (e.g., using the rear right retract float controls  356 , the rear right extend float controls  358 , the rear left retract float controls  376 , the rear left extend float controls  378 , etc.). 
     As shown in  FIG.  27   , the leveling system  100  of the lift device  10  is arranged in a second configuration, shown as front float configuration  104 . In the front float configuration  104 , the front right leveling actuator  200  of the front right leveling assembly  110  and the front left leveling actuator  220  of the front left leveling assembly  130  are selectively fluidly coupled to each other (e.g., by engaging the front right float valve  314  of the front right float module  312  and the front left float valve  334  of the front left float module  332 , while the rear right float valve  354  of the rear right float module  352  and the rear left float valve  374  of the rear left float module  372  remain disengaged, etc.) such that the front right leveling assembly  110  and the front left leveling assembly  130  function as if the virtual axle  500  extends therebetween with the virtual pivot point  502  positioned along and at the center of the virtual axle  500 . The front float configuration  104  therefore forms the stability triangle  504  between the tractive element  16  of the rear right leveling assembly  150 , the tractive element  16  of the rear left leveling assembly  170 , and the virtual pivot point  502 , rather than a stability rectangle or square between the four tractive elements  16  of the lift device  10 . 
     While the leveling system  100  of the lift device  10  is arranged in the front float configuration  104 , (i) the front right leveling assembly  110  and the front left leveling assembly  130  freely float in response to fluid flowing freely between the front right leveling actuator  200  and the front left leveling actuator  220  (i.e., as the front right leveling actuator  200  extends, the front left leveling actuator  220  retracts, and vice versa) as the tractive elements  16  thereof encounter the terrain and (ii) the rear right leveling actuator  240  of the rear right leveling assembly  150  and the rear left leveling actuator  260  of the rear left leveling assembly  170  are each independently and actively controllable. Further, as the front right leveling assembly  110  and the front left leveling assembly  130  freely float while the leveling system  100  of the lift device  10  is arranged in the front float configuration  104 , the height of the virtual pivot point  502  relative to ground may be selectively adjusted (e.g., increased, decreased, etc.) by manipulating (e.g., increasing, decreasing, etc.) the volume of fluid flowing between the front right leveling actuator  200  and the front left leveling actuator  220  (e.g., using the front right retract float controls  316 , the front right extend float controls  318 , the front left retract float controls  336 , the front left extend float controls  338 , etc.). 
     As shown in  FIG.  28   , the leveling system  100  of the lift device  10  is arranged in a third configuration, shown as left float configuration  106 . In the left float configuration  106 , the front left leveling actuator  220  of the front left leveling assembly  130  and the rear left leveling actuator  260  of the rear left leveling assembly  170  are selectively fluidly coupled to each other (e.g., by engaging the front left float valve  334  of the front left float module  332  and the rear left float valve  374  of the rear left float module  372 , while the front right float valve  314  of the front right float module  312  and the rear right float valve  354  of the rear right float module  352  remain disengaged, etc.) such that the front left leveling assembly  130  and the rear left leveling assembly  170  function as if the virtual axle  500  extends therebetween with the virtual pivot point  502  positioned along and at the center of the virtual axle  500 . The left float configuration  106  therefore forms the stability triangle  504  between the tractive element  16  of the front right leveling assembly  110 , the tractive element  16  of the rear right leveling assembly  150 , and the virtual pivot point  502 , rather than a stability rectangle or square between the four tractive elements  16  of the lift device  10 . 
     While the leveling system  100  of the lift device  10  is arranged in the left float configuration  106 , (i) the front left leveling assembly  130  and the rear left leveling assembly  170  freely float in response to fluid flowing freely between the front left leveling actuator  220  and the rear left leveling actuator  260  (i.e., as the front left leveling actuator  220  extends, the rear left leveling actuator  260  retracts, and vice versa) as the tractive elements  16  thereof encounter the terrain and (ii) the front right leveling actuator  200  of the front right leveling assembly  110  and the rear right leveling actuator  240  of the rear right leveling assembly  150  are each independently and actively controllable. Further, as the front left leveling assembly  130  and the rear left leveling assembly  170  freely float while the leveling system  100  of the lift device  10  is arranged in the left float configuration  106 , the height of the virtual pivot point  502  relative to ground may be selectively adjusted (e.g., increased, decreased, etc.) by manipulating (e.g., increasing, decreasing, etc.) the volume of fluid flowing between the front left leveling actuator  220  and the rear left leveling actuator  260  (e.g., using the front left retract float controls  336 , the front left extend float controls  338 , the rear left retract float controls  376 , the rear left extend float controls  378 , etc.). 
     As shown in  FIG.  29   , the leveling system  100  of the lift device  10  is arranged in a fourth configuration, shown as right float configuration  108 . In the right float configuration  108 , the front right leveling actuator  200  of the front right leveling assembly  110  and the rear right leveling actuator  240  of the rear right leveling assembly  150  are selectively fluidly coupled to each other (e.g., by engaging the front right float valve  314  of the front right float module  312  and the rear right float valve  354  of the rear right float module  352 , while the front left float valve  334  of the front left float module  332  and the rear left float valve  374  of the rear left float module  372  remain disengaged, etc.) such that the front right leveling assembly  110  and the rear right leveling assembly  150  function as if the virtual axle  500  extends therebetween with the virtual pivot point  502  positioned along and at the center of the virtual axle  500 . The right float configuration  108  therefore forms the stability triangle  504  between the tractive element  16  of the front left leveling assembly  130 , the tractive element  16  of the rear left leveling assembly  170 , and the virtual pivot point  502 , rather than a stability rectangle or square between the four tractive elements  16  of the lift device  10 . 
     While the leveling system  100  of the lift device  10  is arranged in the right float configuration  108 , (i) the front right leveling assembly  110  and the rear right leveling assembly  150  freely float in response to fluid flowing freely between the front right leveling actuator  200  and the rear right leveling actuator  240  (i.e., as the front right leveling actuator  200  extends, the rear right leveling actuator  240  retracts, and vice versa) as the tractive elements  16  thereof encounter the terrain and (ii) the front left leveling actuator  220  of the front left leveling assembly  130  and the rear left leveling actuator  260  of the rear left leveling assembly  170  are each independently and actively controllable. Further, as the front right leveling assembly  110  and the rear right leveling assembly  150  freely float while the leveling system  100  of the lift device  10  is arranged in the right float configuration  108 , the height of the virtual pivot point  502  relative to ground may be selectively adjusted (e.g., increased, decreased, etc.) by manipulating (e.g., increasing, decreasing, etc.) the volume of fluid flowing between the front right leveling actuator  200  and the rear right leveling actuator  240  (e.g., using the front right retract float controls  316 , the front right extend float controls  318 , the rear right retract float controls  356 , the rear right extend float controls  358 , etc.). 
     In some embodiments, the leveling system  100  is reconfigurable such that the front right leveling actuator  200  of the front right leveling assembly  110  and the rear left leveling actuator  260  of the rear left leveling assembly  170  are selectively fluidly coupled to each other (e.g., by engaging the front right float valve  314  of the front right float module  312  and the rear left float valve  374  of the rear left float module  372 , while the front left float valve  334  of the front left float module  332  and the rear right float valve  354  of the rear right float module  352  remain disengaged, etc.) such that the front right leveling assembly  110  and the rear left leveling assembly  170  function as if the virtual axle  500  extends therebetween with the virtual pivot point  502  positioned along and at the center of the virtual axle  500 . In such a configuration, (i) the front right leveling assembly  110  and the rear left leveling assembly  170  freely float in response to fluid flowing freely between the front right leveling actuator  200  and the rear left leveling actuator  260  (i.e., as the front right leveling actuator  200  extends, the rear left leveling actuator  260  retracts, and vice versa) as the tractive elements  16  thereof encounter the terrain and (ii) the front left leveling actuator  220  of the front left leveling assembly  130  and the rear right leveling actuator  240  of the rear right leveling assembly  150  are each independently and actively controllable. In other embodiments, the leveling system  100  is not reconfigurable such that the front right leveling actuator  200  of the front right leveling assembly  110  and the rear left leveling actuator  260  of the rear left leveling assembly  170  are selectively fluidly coupled to each other (e.g., in an embodiment where only adjacent leveling assemblies are fluidly couplable, etc.). 
     In some embodiments, the leveling system  100  is reconfigurable such that the front left leveling actuator  220  of the front left leveling assembly  130  and the rear right leveling actuator  240  of the rear right leveling assembly  150  are selectively fluidly coupled to each other (e.g., by engaging the front left float valve  334  of the front left float module  332  and the rear right float valve  354  of the rear right float module  352 , while the front right float valve  314  of the front right float module  312  and the rear left float valve  374  of the rear left float module  372  remain disengaged, etc.) such that the front left leveling assembly  130  and the rear right leveling assembly  150  function as if the virtual axle  500  extends therebetween with the virtual pivot point  502  positioned along and at the center of the virtual axle  500 . In such a configuration, (i) the front left leveling assembly  130  and the rear right leveling assembly  150  freely float in response to fluid flowing freely between the front left leveling actuator  220  and the rear right leveling actuator  240  (i.e., as the front left leveling actuator  220  extends, the rear right leveling actuator  240  retracts, and vice versa) as the tractive elements  16  thereof encounter the terrain and (ii) the front right leveling actuator  200  of the front right leveling assembly  110  and the rear left leveling actuator  260  of the rear left leveling assembly  170  are each independently and actively controllable. In other embodiments, the leveling system  100  is not reconfigurable such that the front left leveling actuator  220  of the front left leveling assembly  130  and the rear right leveling actuator  240  of the rear right leveling assembly  150  are selectively fluidly coupled to each other (e.g., in an embodiment where only adjacent leveling assemblies are fluidly couplable, etc.). 
     According to the exemplary embodiment shown in  FIG.  30   , the lift device control system  400  for the lift device  10  includes a controller  410 . In one embodiment, the controller  410  is configured to selectively engage, selectively disengage, control, and/or otherwise communicate with components of the lift device  10  (e.g., actively control the components thereof, etc.). As shown in  FIG.  30   , the controller  410  is coupled to the turntable  14 , the drive actuators  18 , brakes  46 , the boom  40 , the actuator circuit  300 , various sensors including the steering sensors  280 , displacement sensors  402 , roll sensors  404 , pitch sensors  406 , and load sensors  408  (e.g., pressure sensors, etc.), and a user interface  440 . In other embodiments, the controller  410  is coupled to more or fewer components. By way of example, the controller  410  may send and receive signals with the turntable  14 , the drive actuators  18 , the brakes  46 , the boom  40  (e.g., the lower lift cylinder  60 , the upper lift cylinder  80 , etc.), the actuator circuit  300  (e.g., the front right leveling module  310 , the front right float module  312 , the front left leveling module  330 , the front left float module  332 , the rear right leveling module  350 , the rear right float module  352 , the rear left leveling module  370 , the rear left float module  372 , the front right steering module  380 , the front left steering module  382 , the rear right steering module  384 , the rear left steering module  386 , etc.), the steering sensors  280 , the displacement sensors  402 , the roll sensors  404 , the pitch sensors  406 , the load sensors  408 , and/or the user interface  440 . In some embodiments, the roll sensors  404  and the pitch sensors  406  are a single sensor (e.g., an inclinometer, etc.). The controller  410  may be configured to actively control a pitch adjustment and/or a roll adjustment of the lift base  12  to at least improve the orientation of the lift base  12 , the turntable  14 , and/or the boom  40  relative to gravity (e.g., while driving the lift device  10 , while operating the boom  40 , in a longitudinal direction, in lateral direction, etc.). By way of example, the controller  410  may maintain the lift base  12 , the turntable  14 , and/or the boom  40  level relative to gravity. 
     The controller  410  may be implemented as a general-purpose processor, an application specific integrated circuit (ASIC), one or more field programmable gate arrays (FPGAs), a digital-signal-processor (DSP), circuits containing one or more processing components, circuitry for supporting a microprocessor, a group of processing components, or other suitable electronic processing components. According to the exemplary embodiment shown in  FIG.  30   , the controller  410  includes a processing circuit  412  and a memory  414 . The processing circuit  412  may include an ASIC, one or more FPGAs, a DSP, circuits containing one or more processing components, circuitry for supporting a microprocessor, a group of processing components, or other suitable electronic processing components. In some embodiments, the processing circuit  412  is configured to execute computer code stored in the memory  414  to facilitate the activities described herein. The memory  414  may be any volatile or non-volatile computer-readable storage medium capable of storing data or computer code relating to the activities described herein. According to an exemplary embodiment, the memory  414  includes computer code modules (e.g., executable code, object code, source code, script code, machine code, etc.) configured for execution by the processing circuit  412 . In some embodiments, controller  410  represents a collection of processing devices (e.g., servers, data centers, etc.). In such cases, the processing circuit  412  represents the collective processors of the devices, and the memory  414  represents the collective storage devices of the devices. 
     In one embodiment, the user interface  440  includes a display and an operator input. The display may be configured to display a graphical user interface, an image, an icon, and/or still other information. In one embodiment, the display includes a graphical user interface configured to provide general information about the left device (e.g., vehicle speed, fuel level, warning lights, battery level, etc.). The graphical user interface may also be configured to display a current position of the leveling system  100 , a current position of the boom  40 , a current position of the turntable  14 , an orientation of the lift base  12  (e.g., angle relative to a ground surface, etc.), stability characteristics of the lift base  12 , and/or still other information relating to the lift device  10  and/or the leveling system  100 . 
     The operator input may be used by an operator to provide commands to at least one of the turntable  14 , the drive actuators  18 , the brakes  46 , the boom  40 , and the actuator circuit  300 . The operator input may include one or more buttons, knobs, touchscreens, switches, levers, joysticks, pedals, a steering wheel, or handles. The operator input may facilitate manual control of some or all aspects of the operation of the lift device  10 . It should be understood that any type of display or input controls may be implemented with the systems and methods described herein. 
     According to an exemplary embodiment, the controller  410  is configured to receive steering data from the steering sensors  280 , displacement data from the displacement sensors  402 , roll data from the roll sensors  404 , pitch data from the pitch sensors  406 , and/or pressure data from the load sensors  408 . The displacement sensors  402  may be positioned to acquire the displacement data regarding the front right leveling actuator  200 , the front left leveling actuator  220 , the rear right leveling actuator  240 , and/or the rear left leveling actuator  260 . The displacement data may be indicative of an amount of displacement and/or a position (e.g., extension, retraction, etc.) of the front right leveling actuator  200 , the front left leveling actuator  220 , the rear right leveling actuator  240 , and/or the rear left leveling actuator  260  (e.g., relative to a neutral position, a nominal position, a minimum position, a maximum position, etc.). The roll sensors  404  may be positioned to acquire the roll data indicative of a roll angle of the lift base  12  (e.g., relative to a horizontal roll alignment, a zero roll angle, etc.). The pitch sensors  406  may be positioned to acquire the pitch data indicative of a pitch angle of the lift base  12  (e.g., relative to a horizontal pitch alignment, a zero pitch angle, etc.). The load sensors  408  may be positioned to acquire the pressure data regarding the bore side pressure and/or the rod side pressure within each of the front right leveling actuator  200 , the front left leveling actuator  220 , the rear right leveling actuator  240 , and/or the rear left leveling actuator  260 . The pressure data may be indicative of a loading experienced by each of the tractive elements  16 . According to an exemplary embodiment, the controller  410  monitors the loading status, the leveling status, the ground following status, and/or the height of the lift base  12  of the lift device  10  using the displacement data, the roll data, the pitch data, and/or the pressure data. 
     According to an exemplary embodiment, the controller  410  is configured to operate the leveling system  100  in various modes. As shown in  FIG.  31   , the lift device  10  is arranged in a shipping, transport, or storage mode. In some embodiments, the controller  410  is configured to reconfigure the lift device  10  into the shipping, transport, or storage mode in response to receiving a command from an operator via the user interface  440  to engage the shipping, transport, or storage mode. In some embodiments, the controller  410  is configured to reconfigure the lift device  10  into the shipping, transport, or storage mode in response to the lift device  10  being turned off. In some embodiments, the controller  410  is configured to reconfigure the lift device  10  out of the shipping, transport, or storage mode in response to the lift device  10  being turned on. 
     As shown in  FIG.  31   , the controller  410  is configured to retract the front right leveling actuator  200 , the front left leveling actuator  220 , the rear right leveling actuator  240 , and the rear left leveling actuator  260  (e.g., to their minimum length, maximum retraction, etc.) such that (i) the front right trailing arm  111 , the front left trailing arm  131 , the rear right trailing arm  151 , and the rear left trailing arm  171  rotate to move the lift base  12  downward to a minimum height (e.g., the minimum ground clearance h, etc.) and (ii) the front right trailing arm  111 , the front left trailing arm  131 , the rear right trailing arm  151 , and the rear left trailing arm  171  extend away from the lift base  12  at upward sloping angle. According to an exemplary embodiment, the shipping, transport, or storage mode reconfigures the lift device  10  such that the lift device  10  provides greater clearance for bridges, wires, etc. while being transported (e.g., via a flatbed truck, etc.). Additionally, the shipping, transport, or storage mode eliminates the potential for the front right leveling actuator  200 , the front left leveling actuator  220 , the rear right leveling actuator  240 , and/or the rear left leveling actuator  260  retracting during transport and, thereby, prevents shipping constraints (e.g., straps, etc.) from becoming slack and the lift device  10  becoming unsecure. 
     As shown in  FIG.  31   , the lift device  10  includes (i) first supports (e.g., lift support, eyelet, etc.), shown as supports  600 , coupled to the rear right trailing arm  151  and the rear left trailing arm  171  (e.g., along the lateral members thereof, etc.) and (ii) second supports, shown as supports  602 , coupled to the top of the turntable  14 , proximate the rear end thereof, etc.). In some embodiments, the supports  600  are additionally or alternatively coupled to front right trailing arm  111  and the front left trailing arm  131  (e.g., along the lateral members thereof, etc.). As shown in  FIG.  31   , the supports  600  and the supports  602  are configured to facilitate lifting the lift device  10  (e.g., with a crane, etc.) while the lift device  10  is in the shipping, transport, or storage mode. According to an exemplary embodiment, the front right trailing arm  111 , the front left trailing arm  131 , the rear right trailing arm  151 , the rear left trailing arm  171 , the front right leveling actuator  200 , the front left leveling actuator  220 , the rear right leveling actuator  240 , and the rear left leveling actuator  260  are designed to be load capable to facilitate such a lift operation of the lift device  10  while in the shipping, transport, or storage mode. 
     According to an exemplary embodiment, the lift device  10  has discrete release outputs for the brakes  46  of (i) the front right leveling assembly  110  and the front left leveling assembly  130  (i.e., the front brakes) and (ii) the rear right leveling assembly  150  and the rear left leveling assembly  170  (i.e., the rear brakes). In various situations, the controller  410  operates the brakes  46  in a discrete braking mode where the controller  410  may be configured to (i) release the front brakes and the rear brakes at different times or (ii) only release one of the front brakes or the rear brakes to prevent the tractive elements  16  from sliding or skidding during extension and retraction of (a) the leveling actuators and/or (b) the steering actuators. 
     By way of example, the controller  410  may be configured to release only one of the front brakes or the rear brakes when entering into or out of the shipping, transport, and/or storage mode. For example, entering into and out of the shipping, transport, and/or storage mode changes the wheel base w of the lift device  10  because the trailing arms pivot to an angle both above and below a horizontal. Specifically, the wheel base w of the lift device  10  is at a maximum when the trailing arms are completely horizontal and the wheel base w of the lift device  10  is less than the maximum when the trailing arms are pivoted above horizontal or below horizontal. Accordingly, the controller  410  may be configured to only release one of the front brakes or the rear brakes during the transition into or out of the shipping, transport, and/or storage mode to prevent (i) sliding of the tractive elements  16  if none of the brakes  46  were released or (ii) uncontrolled rolling of the lift device  10  if all of the brakes  46  were released simultaneously. Therefore, if the controller  410  only releases the front brakes, the front tractive elements  16  will roll forward as the wheel base w increases (e.g., as the trailing arms pivot from an angle below horizontal to horizontal, as the trailing arms pivot from an angle above horizontal to horizontal, etc.) and/or roll backward as the wheel base decreases (e.g., as the trailing arms pivot from horizontal to an angle above horizontal, as the trailing arms pivot from horizontal to an angle below horizontal, etc.). While explained in relation to releasing the front brakes, the same may be true for releasing the rear brakes instead of the front brakes. 
     By way of another example, the controller  410  may be configured to release only one of the front brakes or the rear brakes when the controller  410  receives a steer command, but no drive command. In such an instance, the controller  410  may be configured to release the front brakes to allow the front tractive elements to roll and be steered more freely, while maintaining the back brakes engaged to prevent any forward or backward movement of the lift device  10 , especially if the lift device  10  is on a slope. While again explained in relation to releasing the front brakes, the same may be true for releasing the rear brakes instead of the front brakes. 
     According to an exemplary embodiment, the controller  410  is configured to operate the lift device  10  in an adaptive oscillation mode where the controller  410  is configured to selectively and adaptively reconfigure the leveling system  100  between the rear float configuration  102 , the front float configuration  104 , the left float configuration  106 , and the right float configuration  108 . By way of example, the controller  410  may be configured to adaptively switch between the rear float configuration  102 , the front float configuration  104 , the left float configuration  106 , and the right float configuration  108  based on a current center of gravity  506  of the lift device  10  (see, e.g.,  FIGS.  26 - 29   ) to maintain optimal stability for the lift device  10  (e.g., the controller  410  may change between pairs of fluidly coupled leveling actuators in real time as is appropriate due to movement of the center of gravity  506 , etc.). The center of gravity  506  may be determined based on the pressure data acquired by the load sensors  408 . By way of example, the controller  410  is configured to interpret the pressure data for each of the front right leveling actuator  200 , the front left leveling actuator  220 , the rear right leveling actuator  240 , and the rear left leveling actuator  260 . Based on the pressure data, the controller  410  is configured to determine the load on each of the tractive elements  16  to determine which two of the tractive elements  16  are experiencing a “heavier” loading and which two of the tractive elements  16  are experiencing a “lighter” loading. In other embodiments, the center of gravity  506  is not determined. Rather, the knowledge of the position of the components of the lift device  10  (e.g., the boom  40 , the turntable  14 , etc.) and/or force measurements on the tractive elements  16  are used to determine which pair of actuators are appropriate to float. 
     The controller  410  is then configured to enter the two leveling assemblies (e.g., of the front right leveling assembly  110 , the front left leveling assembly  130 , the rear right leveling assembly  150 , the rear left leveling assembly  170 , etc.) associated with the two tractive elements  16  that have the lighter loading into a float mode and enter the other two leveling assemblies associated with the other two tractive elements  16  that have a heavier loading into an active mode. Accordingly, the controller  410  is configured to engage the two float modules (e.g., of the front right float module  312 , the front left float module  332 , the rear right float module  352 , the rear left float module  372 , etc.) associated with the two tractive elements  16  that have the lighter loading to fluidly couple the two leveling actuators thereof (e.g., of the front right leveling actuator  200 , the front left leveling actuator  220 , the rear right leveling actuator  240 , the rear left leveling actuator  260 , etc.) together such that they freely float. The controller  410  is configured to monitor the loading such that as the loads on the tractive elements  16  change (e.g., as the boom  40 , the turntable  14 , etc. are manipulated), the controller  410  shifts which two float modules are engaged, and which two float modules are disengaged. In some embodiments, only adjacent actuators are fluidly coupled together (see, e.g.,  FIGS.  26 - 29   ). 
     While adaptively controlling which two float modules are engaged and which two float modules are disengaged, the controller  410  is configured to maintain the lift base  12  level or substantially level relative to gravity by (i) actively controlling the two leveling actuators associated with the non-engaged float modules with the leveling modules associated therewith (e.g., the front right leveling module  310 , the front left leveling module  330 , the rear right leveling module  350 , the rear left leveling module  370 , etc.) and (ii) actively controlling the height of the virtual pivot point  502  between the two fluidly coupled leveling assemblies (e.g., via the extend and retract float controls associated with the two fluidly coupled leveling actuators, etc.) based on the displacement data, the pitch data, and/or the roll data. 
     In some embodiments, the controller  410  is configured to control the float valves (e.g., the front right float valve  314 , the front left float valve  334 , the rear right float valve  354 , the rear left float valve  374 , etc.) and the leveling modules (e.g., the front right leveling module  310 , the front left leveling module  330 , the rear right leveling module  350 , the rear left leveling module  370 , etc.) of the fluidly coupled leveling actuators such that fluid flows in a desired direction (i.e., one direction at a time) between a heavier loaded leveling actuator to a lighter loaded leveling actuator of the two fluidly coupled leveling actuators. By way of example, if the front right leveling actuator  200  and the front left leveling actuator  220  are fluidly coupled and “freely floating” (i.e., the front tractive elements  16  are lighter than the rear tractive elements  16 ), and the pressure in the front right leveling actuator  200  is greater than the pressure in the front left leveling actuator  220 , (i) the front right float valve  314  and the front left float valve  334  may be engaged (i.e., to enter the front right leveling assembly  110  and the front left leveling assembly  130  into the float mode) and (ii) the front right leveling module  310  and the front left leveling module  330  may be controlled such that fluid can only flow out of the front right leveling actuator  200  and into the front left leveling actuator  220 . 
     According to an exemplary embodiment, the controller  410  is configured to operate the lift device  10  in an auto level mode (e.g., while driving, etc.) that keeps the lift device  10  level or substantially level relative to gravity while maintaining the leveling actuators (e.g., the front right leveling actuator  200 , the front left leveling actuator  220 , the rear right leveling actuator  240 , the rear left leveling actuator  260 , etc.) at a position of extension or retraction that is away from the endpoints thereof (e.g., maximum extension, maximum retraction, etc.). By way of example, extended operation of the lift device  10  in the auto level mode could cause the lift base  12  to “walk up” or “walk down” since there are potentially many possible solutions to provide a level lift base  12  (e.g., the height of the leveling actuators may all be able to be reduced in half and still provide a level chassis, etc.). In some embodiments, the controller  410  is configured to maintain the leveling actuators at or close to the midpoint of the leveling actuators while simultaneously keeping the lift device  10  level relative to gravity during the auto level mode. In some embodiments, the controller  410  is configured to cutout drive system commands in response to a sudden change in ground profile until a level condition is reestablished. In some embodiments, the controller  410  is configured to switch from the auto level mode to a high-speed drive mode in response to a command requesting the lift device  10  to driven at a speed above a threshold speed. The auto level mode and the high-speed drive mode are described in greater detail herein with respect to methods  700 ,  800 , and  900 . 
     Referring now to  FIG.  32   , a method  700  for centering chassis height of the lift device  10  during an auto level mode is shown, according to an exemplary embodiment. At step  702 , the controller  410  is configured to implement a calibration procedure. The calibration procedure includes (i) determining a maximum length or stroke of the leveling actuators of the leveling system  100  (e.g., by extending the front right leveling actuator  200 , the front left leveling actuator  220 , the rear right leveling actuator  240 , and the rear left leveling actuator  260  to a maximum extension position, etc.) (step  704 ) and (ii) determining a minimum length or stroke of the leveling actuators of the leveling system  100  (e.g., by retracting the front right leveling actuator  200 , the front left leveling actuator  220 , the rear right leveling actuator  240 , and the rear left leveling actuator  260  to a minimum extension position, etc.) (step  706 ). The controller  410  may be configured to determine the maximum length and the minimum length based on displacement data acquired by the displacement sensors  402 . The controller  410  may perform the calibration procedure at startup, periodically, and/or when commanded to perform the calibration procedure. 
     At step  708 , the controller  410  is configured to determine a current maximum length of the most extended leveling actuator of the front right leveling actuator  200 , the front left leveling actuator  220 , the rear right leveling actuator  240 , and the rear left leveling actuator  260 . At step  710 , the controller  410  is configured to determine a current minimum length of the least extended leveling actuator of the front right leveling actuator  200 , the front left leveling actuator  220 , the rear right leveling actuator  240 , and the rear left leveling actuator  260 . The controller  410  may be configured to determine the current maximum length and the current minimum length based on displacement data acquired by the displacement sensors  402 . 
     At step  712 , the controller  410  is configured to determine a height adjustment value based on the maximum length, the minimum length, the current maximum length, and the current minimum length. According to an exemplary embodiment, the controller  410  is configured to determine the height adjustment value using the following expression: 
     
       
         
           
             
               
                 
                   
                     Δ 
                     ⁢ 
                     h 
                   
                   = 
                   
                     
                       
                         ( 
                         
                           
                             ( 
                             
                               
                                 h 
                                 max 
                               
                               - 
                               
                                 h 
                                 min 
                               
                             
                             ) 
                           
                           - 
                           
                             h 
                             
                               max 
                               current 
                             
                           
                         
                         ) 
                       
                       - 
                       
                         ( 
                         
                           
                             h 
                             
                               min 
                               current 
                             
                           
                           - 
                           0 
                         
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                     2 
                   
                 
               
               
                 
                   ( 
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     where Δh is the height adjustment value, h max  is the maximum length, h min  is the minimum length, h max     current    is the current maximum length of the most extended leveling actuator, and h min     current    is the current minimum length of the least extended leveling actuator. 
     At step  714 , the controller  410  is configured to adjust the current height of each of the front right leveling actuator  200 , the front left leveling actuator  220 , the rear right leveling actuator  240 , and the rear left leveling actuator  260  by the height adjustment value. According to an exemplary embodiment, method  700  facilitates preventing “walk up” or “walk down” of the lift base  12  over time by actively driving the leveling actuators toward a position that is away from maximum lengths and minimum lengths thereof and toward the mid-points thereof, while maintaining the lift base  12  level or substantially level. 
     Referring now to  FIG.  33   , a method  800  for initiating a drive command cutout during the auto level mode is shown, according to an exemplary embodiment. At step  802 , the controller  410  is configured to determine whether a drive command is being provided thereto (e.g., via an operator using the user interface  440 , etc.). If no drive command is being provided, the controller  410  is configured to wait for such drive command before proceeding. In some embodiments, the controller  410  may initiate the adaptive oscillation mode and/or the shipping, transport, or storage mode when a drive command is not being provided (e.g., after a designated period of time, etc.). When a drive command is provided, at step  804 , the controller  410  is configured to determine whether the lift device  10  is currently within a level threshold (e.g., not leaning more than 10 degrees in any direction, etc.). If yes, the controller  410  is configured to proceed to step  806 , otherwise the controller  410  is configured to proceed to step  808 . 
     At step  806 , the controller  410  is configured to drive the lift device  10  based on the drive command (e.g., engage the drive actuators  18 , etc.) and auto level the lift device  10  as the lift device  10  is driven (e.g., actively and independently control each of the front right leveling actuator  200 , the front left leveling actuator  220 , the rear right leveling actuator  240 , and the rear left leveling actuator  260  to maintain the lift device  10  level or substantially level to gravity, etc.). During the auto leveling, the controller  410  may be configured to implement steps  708 - 714  of method  700 . 
     At step  808 , the controller  410  is configured to cutout (i.e., disregard) the drive command, but auto level the lift device  10 . During the auto leveling, the controller  410  may be configured to implement steps  708 - 714  of method  700 . Step  808  may be implemented by the controller  410  in scenarios where the lift device  10  encounters an abrupt change in the ground profile and the auto leveling cannot keep up and maintain the lift device  10  within the level threshold. Once the auto leveling corrects for the abrupt change, the controller  410  may reinstitute the drive command. 
     Referring now to  FIG.  34   , a method  900  for switching from the auto level mode to a high-speed drive mode is shown, according to an exemplary embodiment. At step  902 , the controller  410  is configured to determine a current speed of the lift device  10 . At step  904 , the controller  410  is configured to determine whether the current speed is at a speed threshold (e.g., a high speed, etc.). If the current speed is below the speed threshold, the controller  410  is configured to perform the auto level mode (see, e.g., methods  700  and  800 ). If the current speed is at or above the speed threshold, the controller  410  is configured to switch from the auto level mode to the high-speed drive mode. 
     At step  906 , the controller  410  is configured to provide a command to the rear right leveling actuator  240  and the rear left leveling actuator  260  to reposition them to or near their mid-stroke positions. At step  908 , the controller  410  is configured to float the front right leveling actuator  200  and the front left leveling actuator  220  (see, e.g.,  FIG.  27   ). At step  910 , the controller  410  is configured to determine a current position of the front right leveling actuator  200  and the front left leveling actuator  220  to identify an average position of the two (e.g., the virtual pivot point  502 , etc.). The controller  410  may be configured to determine the average position based on displacement data acquired by the displacement sensors  402 . 
     At step  912 , the controller  410  is configured to provide an identical command to the front right leveling actuator  200  and the front left leveling actuator  220  such that the average position (e.g., the virtual pivot point  502 , etc.) is a virtual mid-point of the front right leveling assembly  110  and the front left leveling assembly  130  (e.g., the virtual pivot point  502  is at a mid-point between a maximum possible height of the virtual pivot point  502  and a minimum possible point of the virtual pivot point  502 , etc.). At step  914 , the controller  410  is configured to switch the lift device  10  into the high-speed drive mode from the auto level mode and allow the speed of the lift device  10  to increase above the threshold speed. 
     As utilized herein, the terms “approximately,” “about,” “substantially”, and similar terms are intended to have a broad meaning in harmony with the common and accepted usage by those of ordinary skill in the art to which the subject matter of this disclosure pertains. It should be understood by those of skill in the art who review this disclosure that these terms are intended to allow a description of certain features described and claimed without restricting the scope of these features to the precise numerical ranges provided. Accordingly, these terms should be interpreted as indicating that insubstantial or inconsequential modifications or alterations of the subject matter described and claimed are considered to be within the scope of the disclosure as recited in the appended claims. 
     It should be noted that the term “exemplary” and variations thereof, as used herein to describe various embodiments, are intended to indicate that such embodiments are possible examples, representations, or illustrations of possible embodiments (and such terms are not intended to connote that such embodiments are necessarily extraordinary or superlative examples). 
     The term “coupled” and variations thereof, as used herein, means the joining of two members directly or indirectly to one another. Such joining may be stationary (e.g., permanent or fixed) or moveable (e.g., removable or releasable). Such joining may be achieved with the two members coupled directly to each other, with the two members coupled to each other using a separate intervening member and any additional intermediate members coupled with one another, or with the two members coupled to each other using an intervening member that is integrally formed as a single unitary body with one of the two members. If “coupled” or variations thereof are modified by an additional term (e.g., directly coupled), the generic definition of “coupled” provided above is modified by the plain language meaning of the additional term (e.g., “directly coupled” means the joining of two members without any separate intervening member), resulting in a narrower definition than the generic definition of “coupled” provided above. Such coupling may be mechanical, electrical, or fluidic. 
     References herein to the positions of elements (e.g., “top,” “bottom,” “above,” “below”) are merely used to describe the orientation of various elements in the FIGURES. It should be noted that the orientation of various elements may differ according to other exemplary embodiments, and that such variations are intended to be encompassed by the present disclosure. 
     The hardware and data processing components used to implement the various processes, operations, illustrative logics, logical blocks, modules and circuits described in connection with the embodiments disclosed herein may be implemented or performed with a general purpose single- or multi-chip processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, or, any conventional processor, controller, microcontroller, or state machine. A processor also may be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. In some embodiments, particular processes and methods may be performed by circuitry that is specific to a given function. The memory (e.g., memory, memory unit, storage device) may include one or more devices (e.g., RAM, ROM, Flash memory, hard disk storage) for storing data and/or computer code for completing or facilitating the various processes, layers and modules described in the present disclosure. The memory may be or include volatile memory or non-volatile memory, and may include database components, object code components, script components, or any other type of information structure for supporting the various activities and information structures described in the present disclosure. According to an exemplary embodiment, the memory is communicably connected to the processor via a processing circuit and includes computer code for executing (e.g., by the processing circuit or the processor) the one or more processes described herein. 
     The present disclosure contemplates methods, systems and program products on any machine-readable media for accomplishing various operations. The embodiments of the present disclosure may be implemented using existing computer processors, or by a special purpose computer processor for an appropriate system, incorporated for this or another purpose, or by a hardwired system. Embodiments within the scope of the present disclosure include program products comprising machine-readable media for carrying or having machine-executable instructions or data structures stored thereon. Such machine-readable media can be any available media that can be accessed by a general purpose or special purpose computer or other machine with a processor. By way of example, such machine-readable media can comprise RAM, ROM, EPROM, EEPROM, or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to carry or store desired program code in the form of machine-executable instructions or data structures and which can be accessed by a general purpose or special purpose computer or other machine with a processor. Combinations of the above are also included within the scope of machine-readable media. Machine-executable instructions include, for example, instructions and data which cause a general purpose computer, special purpose computer, or special purpose processing machines to perform a certain function or group of functions. 
     Although the figures and description may illustrate a specific order of method steps, the order of such steps may differ from what is depicted and described, unless specified differently above. Also, two or more steps may be performed concurrently or with partial concurrence, unless specified differently above. Such variation may depend, for example, on the software and hardware systems chosen and on designer choice. All such variations are within the scope of the disclosure. Likewise, software implementations of the described methods could be accomplished with standard programming techniques with rule-based logic and other logic to accomplish the various connection steps, processing steps, comparison steps, and decision steps. 
     It is important to note that the construction and arrangement of the lift device  10 , the leveling system  100 , the actuator circuit  300 , and the lift device control system  400  as shown in the various exemplary embodiments is illustrative only. Additionally, any element disclosed in one embodiment may be incorporated or utilized with any other embodiment disclosed herein. Although only one example of an element from one embodiment that can be incorporated or utilized in another embodiment has been described above, it should be appreciated that other elements of the various embodiments may be incorporated or utilized with any of the other embodiments disclosed herein.