Patent Publication Number: US-10316491-B2

Title: Machine control system having multi-blade position coordination

Description:
TECHNICAL FIELD 
     The present disclosure relates generally to a control system and, more particularly to a machine control system having multi-blade position coordination. 
     BACKGROUND 
     An earth working machine can be equipped with a blade that is selectively lowered into a ground surface to scrape away material and thereby shape a surface contour. For example, a motor grader can include a moldboard located at an underbelly position, between a front wheel and a rear wheel. Any number of hydraulic actuators can be connected to the moldboard and selectively pressurized to raise, lower, rotate, twist, and/or tilt the moldboard to thereby affect a location, angle, and depth of the resulting cut. In some embodiments, the movements of the moldboard may be automated, for example based on an actual ground contour, a planned ground contour, and/or a measured blade position. In another example, a dozer can include a dozing blade located at a leading end, forward of a front wheel. Like the moldboard, any number of hydraulic actuators can be connected to the dozing blade and selectively pressurized to raise, lower, rotate, twist, and/or tilt the dozing blade. 
     Some earth working machines can be simultaneously equipped with multiple different blades. U.S. Pat. No. 7,841,423 that issued to Damm et al. on Nov. 30, 2010 (“the &#39;423 patent”) discloses such a machine. In particular, the &#39;423 patent discloses a motor grader having a mid-located moldboard and a forward-located dozing blade. With this configuration, a motor grader operator could manually complete a rough pass using the dozing blade, followed by an automated final pass using the moldboard. 
     Although the machine of the &#39;423 patent may have increased functionality provided by two different blades, it may also be problematic. In particular, it may be difficult for an operator to manually control the dozing blade, as visibility of an area in front of the dozing blade from inside of a typical motor grader cabin may be poor. 
     The disclosed machine system is directed to overcoming one or more of the problems set forth above and/or other problems of the prior art. 
     SUMMARY 
     In one aspect, the present disclosure is directed to a control system for a machine. The control system may include first blade mountable to the machine and configured to engage a ground surface below the machine, and at least a first actuator configured to move the first blade. The control system may also include a second blade mountable to the machine and configured to engage the ground surface below the machine, and at least a second actuator configured to move the second blade. The control system may additionally include a controller in communication with the at least a second actuator. The controller may be configured to determine a first position of the first blade, and to automatically cause the at least a second actuator to move the second blade to a second position based on the first position of the first blade. 
     In another aspect, the present disclosure is directed to a method for controlling a machine. The method may include determining a ground surface position, determining a planned contour position, and determining a first position of a first ground-engaging blade of the machine. The method may also include determining a mode of operation of the machine, and automatically causing a second ground-engaging blade of the machine to move to a second position based on one of the ground surface position, the planned contour position, and the first position of the first ground-engaging blade of the machine. 
     In another aspect, the present disclosure is directed to a machine. The machine may include a front frame having a steerable front wheel, a rear frame having a driven rear wheel and being pivotally connected to the front frame, a moldboard blade suspended from the front frame between the steerable front wheel and the driven rear wheel, and a first hydraulic actuator configured to move the moldboard blade relative to the front frame. The machine may also include a dozing blade mounted to the front frame forward of the steerable front wheel, and a second hydraulic actuator configured to move the dozing blade relative to the front frame. The machine may further include a first sensor configured to generate a first signal indicative of a position of the moldboard blade, a second sensor configured to generate a second signal indicative of a position of the dozing blade, and a controller in communication with the first hydraulic actuator, the second hydraulic actuator, the first sensor, and the second sensor. The controller may be configured to automatically cause the first hydraulic actuator to move the moldboard blade based on the first signal, and to automatically cause the second hydraulic actuator to move the dozing blade based on the first and second signals. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an side-view perspective illustration of an exemplary disclosed machine; and 
         FIG. 2  is a diagrammatic illustration of an exemplary disclosed system that may be used in conjunction with the machine of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  illustrates an exemplary disclosed mobile machine  10 . In the depicted example, machine  10  is a motor grader. As a motor grader, machine  10  may include a steerable front frame  12 , and a driven rear frame  14  that is pivotally connected to front frame  12 . Front frame  12  may include a pair of front wheels  16  (or other traction devices), and support a cabin  18 . Rear frame  14  may include compartments  20  for housing a power source (e.g., an engine) and associated cooling components, the power source being operatively coupled to rear wheels  22  (or other traction devices) for primary propulsion of machine  10 . Rear wheels  22  may be arranged in tandems at opposing sides of rear frame  14 . Steering of machine  10  may be a function of both front wheel steering and articulation of front frame  12  relative to rear frame  14 . 
     Machine  10  may also include ground-engaging work tools such as, for example, a moldboard blade  24  and a dozing blade  26 . Moldboard blade  24  and dozing blade  26  may both be operatively connected to and supported by front frame  12 . In the disclosed embodiment, moldboard blade  24  hangs from a general midpoint of front frame  12 , at a location between front and rear wheels  16 ,  22 . In this same embodiment, dozing blade  26  is supported at a leading end of front frame  12  (e.g., at a location forward of front wheels  16 , relative to a normal travel direction). In some embodiments, rear frame  14  may also support one or more ground-engaging work tools (e.g., a ripper), if desired. It is contemplated that moldboard blade  24 , dozing blade  26 , and/or the ripper could alternatively be connected to and supported by another portion of machine  10 , such as by another portion of front frame  12  and/or rear frame  14 . 
     Both of moldboard blade  24  and dozing blade  26  may be supported via separate hydraulic arrangements. In particular, a first hydraulic arrangement  28  having any number of different actuators (e.g., cylinders and/or motors) may be configured to shift moldboard blade  24  vertically toward and away from front frame  12 , to shift moldboard blade  24  side-to-side, and/or to rotate moldboard blade  24  about horizontal and/or vertical axes. A second hydraulic arrangement  30  having any number of different actuators may be configured to shift dozing blade  26  vertically toward and away from front frame  12 . It is contemplated that moldboard blade  24  and dozing blade  26  may move in additional and/or different ways than described above, if desired. 
     Cabin  18  may house components configured to receive input from a machine operator indicative of a desired machine and/or work tool movement. Specifically, cabin  18  may house one or more input devices  32  embodied, for example, as single- or multi-axis joysticks located in proximity to an operator seat  34 . Input devices  32  may be proportional-type controllers configured to position or orient machine  10  and the work tools by producing position signals indicative of desired speeds and/or forces in a particular direction. It is contemplated that different input devices  32  may alternatively or additionally be included within cabin  18  such as, for example, wheels, knobs, push-pull devices, switches, pedals, and other operator input devices known in the art. 
     During operation of machine  10 , the operator may manipulate input devices  32  from inside cabin  18  to perform tasks that require high precision. For example, the operator may need to position moldboard blade  24  and/or dozing blade  26  at precise locations and/or in precise orientations in order to create a planned contour at a worksite without causing collision with another portion of machine  10  and/or with obstacles at the worksite. Similarly, the operator may need to move machine  10 , itself, along a precise trajectory. And in order for the operator to make these movements accurately and efficiently, and without damaging machine  10  or its surroundings, the operator may sometimes rely on position-feedback from a locating device  36 . 
     As each machine  10  travels about the worksite, a Global Navigation Satellite System (GNSS), a local laser tracking system, or another type of positioning device or system may communicate with locating device  36  to monitor the movements of machine  10  and/or the ground-engaging work tools (e.g., of moldboard blade  24  and/or dozing blade  26 ) and to generate corresponding position signals. The position signals may be directed to an onboard controller  38  (shown only in  FIG. 2 ), for comparison with an electronic contour plan of the worksite and for further processing. As shown in  FIG. 1 , the further processing may include, among other things, determining a current ground location under machine  10 ; a planned final contour of the worksite; a current elevation of moldboard blade  24  and/or dozing blade  26  relative to the ground location; a current elevation of moldboard blade  24  and/or dozing blade  26  relative to the planned final contour; and/or a current elevation of dozing blade  26  relative to moldboard blade  24 . 
     Controller  38  may embody a single microprocessor or multiple microprocessors that include a means for controlling an operation of machine  10 . Numerous commercially available microprocessors can be configured to perform the functions of controller  38 . Controller  38  can include a memory, a secondary storage device, a processor, and any other components for running an application. Various other circuits may be associated with controller  38  such as power supply circuitry, signal conditioning circuitry, solenoid driver circuitry, and other types of circuitry. 
     The position-feedback described above may be provided visually to the operator of machine  10 . For example, a display  40  may be provided within cabin  18  in proximity to seat  34 . Display  40  may include one or more monitors (e.g., a liquid crystal display (LCD), a cathode ray tube (CRT), a personal digital assistant (PDA), a plasma display, a touch-screen, a portable hand-held device, or any such display device known in the art) configured to actively and responsively show the different elevations described above to the operator of machine  10 . Display  40  may be connected to controller  38 , and controller  38  may execute instructions to render graphics and images on display  40  that are associated with operation of machine  10 . 
     In some embodiments, display  40  may also be configured to receive input indicative of different modes of machine operation. For example, as shown in  FIG. 2 , display  40  may include one or more buttons (real or virtual)  42 , switches, knobs, dials, etc. that, when manipulated by the operator, generate corresponding signals directed to controller  38 . These signals may be used by controller  38  to implement, for example, a manual mode of operation, a semi-autonomous mode of operation, and/or a completely autonomous mode of operation. During the manual mode of operation, the operator of machine  10  may manipulate input devices  32  to directly control movement of moldboard blade  24  and dozing blade  26 . During the semi-autonomous mode of operation, the operator may move input devices  32  to directly control movement of only one work tool (e.g., only moldboard blade  24 ). And in response to the movement of the manually-controlled work tool and/or based on one or more of the relative locations described above, controller  38  may responsively and autonomously regulate movement of the remaining work tool (e.g., dozing blade  26 ). During the autonomous mode of operation, controller  38  may regulate movement of all work tools (e.g., moldboard blade  24  and dozing blade  26 ). 
     As shown in  FIG. 2 , hydraulic arrangement  28 , hydraulic arrangement  30 , input device(s)  32 , controller  38 , and display  40  may together form a control system  44 . In some embodiments, control system  44  may additionally include one or more sensors  46  and/or one or more valves  48  associated with hydraulic arrangements  28  and  30 . As will be explained below, based on input received via input device(s)  32 , based on the electronic plan of the work site, based on the relative locations described above, and/or based on input from locating device  36 , display  40 , and/or sensors  46 , controller  38  may be configured to selectively energize valves  48  to cause corresponding movements of hydraulic arrangements  28 ,  30 . 
     Sensors  46  may be position sensors that are configured to generate signals indicative of the positions of the related work tools (e.g., of the cutting edges of moldboard blade  24  and dozing blade  26 ). In one embodiment, sensors  46  are associated with one or more actuators of hydraulic arrangements  28  and  30 , and configured to detect extensions of the actuators. Based on the detected extensions and known kinematics of machine  10 , controller  38  may be configured to determine the positions of moldboard blade  24  and/or dozing blade  26 . In another embodiment, sensors  46  are joint-angle sensors, configured to detect pivoting of one or more links within hydraulic arrangements  28  and  30 . Based on the detected pivoting and known kinematics of machine  10 , controller  38  may be configured to determine the positions of moldboard blade  24  and/or dozing blade  26 . In yet another embodiment, sensors  46  may be configured to directly measure a position of moldboard blade  24  and/or dozing blade  26  (e.g., relative to front frame  12 ). In any of the disclosed embodiments, the signals generated by sensors  46  may represent offset positions, relative to a position of machine  10  detected by locating device  36 . Other types of sensors  46  may also or alternatively be utilized to determine the cutting edge location of each blade, if desired. It is also contemplated that sensors  46  may be omitted, if desired, and controller  38  may rely solely on signals generated by locating device  36  to determine the cutting edge positions of moldboard and dozing blades  24 ,  26 . 
     Valves  48  may be configured to selective direct pressurized fluid into and/or out of different chambers within the actuators of hydraulic arrangements  28  and/or  30  in response to manual input received via input device  32  and/or in response to commands generated by controller  38 . For example, valves  48  may be movable between positions at which a pump supply passage is connected with a particular chamber, or a tank drain passage is connected with the particular pressure. As is known in the art, these connections may result in an imbalance of pressure inside the associated actuator(s) that functions to either extend or retract the actuator(s). 
     INDUSTRIAL APPLICABILITY 
     The disclosed control system may be applicable to any mobile machine where cooperative control of multiple work tools is desired. The disclosed control system finds particular applicability in construction and earthmoving machines, for example in motor graders that have multiple ground-engaging blades in fore/aft staggered positions. The disclosed control system provides manual, semi-autonomous, and fully autonomous modes of operation, wherein the different blades are cooperatively controlled based on operator input, a contour plan, a detected ground surface location, and/or detected relative positions of the blades. The disclosed system will now be described in more detail below. 
     During operation of machine  10 , the operator may be tasked with transforming a surface at a worksite to match a planned contour. In some instances, this transformation may require removal of a certain depth of material from a particular area at the worksite. Conventionally the material would be removed in one or more rough passes and a subsequent final pass. The conventional process, however, can be inefficient and slow. 
     In the disclosed embodiment, the material normally removed during the rough passes may be removed by dozing blade  26 , while the material normally removed during the subsequent final pass may be removed by moldboard blade  24  during the same pass. This removal of material may be accomplished via any of the available modes of operation described above. 
     For example, in the manual mode of operation, the operator may manipulate a first input device  32  to generate commands directed to hydraulic arrangement  30  (e.g., to valve  48 ), causing the associated actuator(s) to push dozing blade  26  into the ground surface to a first depth. At this same time, the operator may manipulate a second input device  32  to generate commands directed to hydraulic arrangement  28  (e.g., to valve  48 ) causing the associated actuator(s) to push moldboard blade  24  into the ground surface behind dozing blade  26  to a second depth. The second depth, in this embodiment, may generally align with the final planned contour (referring to  FIG. 1 ), while the first depth may be some ratio of the second depth. The ratio used to set the first depth may be at least partially dependent on a type and compaction level of the material being moved. as well as configurations of machine  10 , moldboard blade  24 , and/or dozing blade  26 . The manual mode of operation may be selected, for example, based on input received via buttons  42  on display  40 . Feedback regarding the ground surface location, the final planned contour, and the cutting edge locations of moldboard blade  24  and dozing blade  26  may be determined by controller  38  based on signals from locating device  36  and/or sensors  46 , and shown on display  40 . 
     In the semi-autonomous mode of operation, the operator may manipulate only the second input device  32  to generate commands causing the associated actuator(s) to push moldboard blade  24  into the ground surface behind dozing blade  26  to the second depth. And based on a detected position of moldboard blade  24  (e.g., the elevation of dozing blade  26  from moldboard blade  24 ), based on a known position of the final planned contour (e.g., the elevation of dozing blade  26  from the final planned contour), and/or based on the detected position of the ground surface (e.g., the elevation of dozing blade  26  from the ground surface), controller  38  may automatically generate commands directed to hydraulic arrangement  30  (e.g., to valve  48 ) causing the associated actuator(s) to push dozing blade  26  into the ground surface to the first depth. In this mode of operation, the operator may only need to manually control a single work tool (e.g., moldboard blade  24 , which can be easily seen from inside of cabin  18 ), which greatly eases the burden on the operator. It is contemplated that the operator may alternatively directly control the depth of only dozing blade  26 , if desired, thereby allowing controller  38  to autonomously regulate the depth of moldboard blade  24  in a manner similar to that described above. The semi-autonomous mode of operation may be selected, for example, based on input received via buttons  42  on display  40 . Like operation in the manual mode, controller  38  may also provide feedback during the semi-autonomous mode regarding the ground surface location, the final planned contour, and the cutting edge locations of moldboard blade  24  and dozing blade  26  via display  40 . 
     In the fully-autonomous mode of operation, the operator may not need to manipulate any input device  32 . In particular, controller  38  may autonomously generate commands causing the associated actuator(s) to push moldboard and dozing blades  24 ,  26  into the ground surface to the second and first depths, respectively. For example, based on the known position of the final planned contour and/or based on the detected position of the ground surface, controller  38  may determine the ratio of material that should be removed by each of moldboard and dozing blades  24 ,  26 , and generate corresponding depth commands. The fully-autonomous mode of operation may be selected, for example, based on input received via buttons  42  on display  40 . Like operation in the manual and semi-autonomous modes, controller  38  may also provide feedback during the fully-autonomous mode regarding the ground surface location, the final planned contour, and the cutting edge locations of moldboard blade  24  and dozing blade  26  via display  40 . 
     The disclosed system may simplify motor grader control and provide improved efficiency and contour shaping. Specifically, the disclosed control system may autonomously control the disclosed front-mounted dozing blade, which is normally obstructed from operator view. The automated control of the disclosed front-mounted dozing blade may be coordinated with manual and/or automated control of the disclosed mid-mounted moldboard blade in order to increase an amount of material removed during each pass of the motor grader and to improve accuracy in the resulting contour. The automated control may also reduce the burden on the operator. 
     It will be apparent to those skilled in the art that various modifications and variations may be made to the disclosed control system without departing from the scope of the disclosure. Other embodiments of the disclosed control system will be apparent to those skilled in the art from consideration of the specification and practice of the control system disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope of the disclosure being indicated by the following claims and their equivalents.