Abstract:
A robot and trailer system is disclosed. The robot can have a hitch that can attach to the trailer. The hitch can he remotely controlled to release and detach the trailer from the robot. The front panel of the trailer can be rounded, for example to enable dragging over obstacles with a reduced risk of snagging or catching on the obstacle.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority to U.S. Provisional Application No. 61/696,066, filed 31 Aug. 2012, which is incorporated herein by reference in its entirety. 
     
    
     BACKGROUND 
       [0002]    1. Technical Field 
         [0003]    The invention relates generally to the field of trailers and vehicle connection systems, for example automated release hitch systems. 
         [0004]    2. Summary of the Art 
         [0005]    Remote control robots are often limited in their volumetric capacity to carry cargo. Many robots are attached to trailers in order to increase their cargo carrying capacity. 
         [0006]    The trailers are often manually attached and detached to the robots. This can present problems if the trailer becomes stuck but the robot needs to proceed with or without the trailer. If the operator can not detach the trailer from the robot, the robot and trailer may be unable to complete their task, at best, or may even be unretrievable. Also, if the trailer is carrying hazardous cargo, for example radioactive material to be left in a remote location, it would be undesirable for the operator to be near the trailer, which would be required for the operator to manually remove the trailer from the robot. 
         [0007]    Additionally, the ability for robots to navigate over obstacles, such as their ability to climb stairs or rocks may be critical to their usability. When attached to a trailer, robots climbing capability is often limited by the trailer, if not almost completely incapacitated. Accordingly, during attempted climbing of an obstacle, the robot may become stuck on the obstacle by the trailer. The front edge of the trailer may catch on the obstacle. Common trailers may be unable to climb the obstacle and unable to remotely detach from the robot, thereby leaving the robot and trailer stuck on the obstacle, or preventing the operator from risking an attempt to drive over the obstacle at all. 
         [0008]    When the robot is driven in reverse, trailers often jackknife with respect to the robot. Typical trailers often tilt or tip over when the robot continues to drive in reverse with a jackknifed trailer resulting in a loss of cargo or obstruction of the robot (e.g., the trailer may get trapped under the robot while the robot continues to attempt to drive in reverse). 
         [0009]    Accordingly, a robot and trailer assembly that is capable of remote control detachment of the trailer is desired. Furthermore, a trailer capable of climbing obstacles is desired. Also, a robot and trailer that prevent the trailer from tilting or tipping over when jackknifed is desired. 
       SUMMARY OF THE INVENTION 
       [0010]    A vehicular connection system is disclosed. The system can have a vehicle that can have a chassis and a hitch. The hitch is configured to be remotely controlled. The system can have a trailer. The trailer can have a bed, a wheel, and a coupler. The coupler can be releasably attachable to the hitch. 
         [0011]    The hitch can be configured to be remotely activated by a wireless signal. The hitch can have a solenoid. The system can have a flipper rotatably attached to the robot chassis. The bottom of the front frame of the trailer can have a radius of curvature of less than about 12 in. The front bottom panel can be at an angle of less than about 50° with respect to the bed. The vehicle can be or have a robot. The robot can be configured to be remotely controlled. The vehicle can be configured to be remotely controlled. 
         [0012]    A trailer is also disclosed. The trailer can have a frame, a bed attached to the frame, a coupler attached to the frame, and a wheel having a wheel axis. The wheel axis is attached to the frame. The bottom of the front frame of the trailer has a radius of curvature of less than 12 in. The front bottom panel can be at an angle of less than about 50° with respect to the bed. The rear bottom panel can be at an angle of less than about 50° with respect to the bed. The frame can be lower than the bed. The wheel axis can be above the bottom of the frame. 
         [0013]    A method of using a vehicular connection system is disclosed. The method can include attaching a first vehicle to a trailer, remotely controlling the first vehicle, and detaching the first vehicle from the trailer. Remotely controlling can include sending a signal from a control unit to the first vehicle. Detaching can include sending a wireless signal to the first vehicle. The first vehicle can be or have a robot. 
         [0014]    The first vehicle can have a hitch. The hitch can have a solenoid. Attaching the first vehicle to the trailer can include actuating the solenoid. Detaching the first vehicle from the trailer can include deactivating the solenoid. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]      FIG. 1  illustrates a variation of the robot attached to a variation of the trailer. 
           [0016]      FIGS. 2   a  through  2   f  are front perspective, rear perspective, bottom-front perspective, bottom-rear perspective, top, and side perspective views, respectively, of a variation of the trailer. 
           [0017]      FIGS. 3   a  and  3   b  are top and rear perspective views, respectively of a variation of the hitch. 
           [0018]      FIGS. 4   a  and  4   b  are top and rear perspective views, respectively of a variation of the hitch in a first position. 
           [0019]      FIG. 4   c ′ illustrates a variation of the receiver. 
           [0020]      FIGS. 5   a  and  5   b  are top and rear perspective views, respectively of the variation of the hitch of  FIGS. 4   a  and  4   b  in a second position. 
           [0021]      FIGS. 6   a  and  6   b  are top and side cross-sectional views of a portion of variations of the hitch during a method of sliding the receiver into the remainder of the hitch. 
           [0022]      FIG. 7  is a side cut-away view of a portion of a variation of the hitch during a method of locking the receiver to the remainder of the hitch. 
           [0023]      FIG. 8  is a top cross-sectional view of a variation of the hitch during a method of releasing and detaching the receiver from the remainder of the hitch. 
           [0024]      FIGS. 9   a  through  9   c  are front perspective views of a variation of the hitch during a method for attaching the receiver to the remainder of the hitch. 
           [0025]      FIGS. 10   a  through  10   d  are partial see-through perspective, front, front left perspective, and front right perspective views, respectively,  FIGS. 10   b  and  10   c  are shown without (or shown in see-through) the hitch frame or hitch lid for illustrative purposes. 
       
    
    
     DETAILED DESCRIPTION 
       [0026]      FIG. 1  illustrates that a robot  10  can be removably attached to a trailer  12 . The trailer  12  can have a trailer frame  14 . The robot  10  can be the robot as described by, or have any combination of elements thereof as described by U.S. Pat. No. 8,100,205, issued 24 Jan. 2012, or U.S. Provisional Patent Application No. 61/586,238, filed 13 Jan. 2012, both of which are incorporated herein by reference in their entireties. For example, the robot  10  can have one, two, four or more flippers  16  rotatably attached to the robot chassis. The flippers  16  can have tracks  18  that can translate around the body of the flipper  16  to translate and steer the robot  10 . The robot  10  can have a payload bay  20  into which payload  22  can be mounted and electronically connected to the robot  10 . For example, the payload  22  can be a rotatable camera, a chemical sensor, a robotic arm, or combinations thereof. The robot  10  can have cameras, display screens, microphones, speakers, radios or combinations thereof. The robot  10  and payload  22  can be controlled by remote control. The robot  10  and payload  22  can transmit data, such as audio, video, sensed environmental data (e.g., chemical levels, temperature), or combinations thereof, to and/or from a remote control unit. 
         [0027]    The robot  10  can have a hitch  24 . The hitch can extend rearward from the rear end of the robot. The hitch can removably attach to the front terminal end of the trailer or trailer frame. The remote control unit can send wireless signals to the robot  10  to control the robot  10 , for example to drive the robot  10  and to actuate the hitch  24  to detach the trailer  12  from the robot  10 . 
         [0028]    The trailer frame  14  can be made from tubular lengths of hard plastic and/or metal, for example aluminum or steel. 
         [0029]    The trailer  12  can have wheels  26 . For example, the trailer can have one or two wheels  26  on each of opposite lateral sides of the trailer  12 . The trailer wheels  26  can be attached to the terminal distal end of the trailer frame  14 . The trailer wheels  26  can extend rearward of the remainder of the trailer  12 . 
         [0030]    The trailer  12  can have a flat trailer bed  28 . The trailer bed  28  can be surrounded by trailer walls  30  extending vertically on all sides of the trailer bed  28 . The trailer bed  28  and trailer walls  30  can be formed from a single panel or multiple panels. The trailer bed  28  and/or walls  30  can be made of mesh, fabric, wood, netting, rubber, concrete, or any other suitable material that can depend on the application the trailer  12  is used for, or combinations thereof. The trailer bed  28  and trailer walls  30  can be attached to the trailer frame  14 . 
         [0031]    The robot  10  can have a robot longitudinal axis  32 . The trailer  12  can have a trailer longitudinal axis  34 . The trailer longitudinal axis  34  and the robot longitudinal axis  32  can intersect at a trailer angle  36 . The trailer angle  36  can change as the trailer  12  rotates with respect to the robot  10 . The trailer angle  36  can be from about −120° to about 120°. For example, the trailer  12  can jackknife and the side of the trailer  12  can contact or abut one of the rear flippers  16  of the robot  10 , such as when the robot  10  is driving in reverse. 
         [0032]    The hitch  24  can have a single degree of rotational freedom about a vertical axis. :For example, the trailer  12  can be rotatably attached at the hitch  24  around an axis extending vertically (as shown in  FIG. 1 ) through the hitch  24 , but can be non-rotatably attached to the hitch  24  in other dimensions. For example, the trailer bed  28  of the trailer  12  can remain in the same plane when the trailer  12  is pushed, skidding backward by the robot  10  when the trailer  12  has jackknifed and the robot  10  is driving in reverse. (The trailer  12  can skid because the rotational axis of the trailer wheels  26  would be non-perpendicular to the direction of translation of the trailer  12  since the trailer  12  would be jackknifed and the side of the trailer  12  would be abutting the side of the robot  10 .) 
         [0033]      FIGS. 2   a  through  2   f  illustrate that the wheels  26  can be attached to the trailer frame  14  at the bottom and rear terminal ends of the trailer frame  14 . The wheels  26  can rotate around wheel axles  38  centered in the wheels  26 . The wheel axles  38  can be above, at the height of, or below the bed  28 . The wheel axles  38  can be mounted above and on top of the bottom-most segments of the trailer frame  14 . 
         [0034]    The bottom front and/or bottom rear portions of the trailer wall  30  can slope toward the bed  28 . For example, the bottom front portion can have a front slider  40   a  and/or the bottom rear can have a rear slider  40   b.  The sliders  40  can be angled, for example at slider angles  42  with respect to the respective adjacent plane of the bed  28  and/or to the top of the front and rear portions of the trailer wall  30 . The slider angles  42  can be less than about 50° with respect to the bed, more narrowly less than 30°, for example about 45°. 
         [0035]    The front bottom of the frame  14  that extends around the front slider  40   a  can be frame climber segments  44 . The frame climber segments  44  can be curved at a frame climber radius of curvature  46 . The frame climber radius of curvature  46  can be less than about 12 in., more narrowly less than about  6  in, yet more narrowly less than about 3 in., for example about 2.5 in. When the trailer  12  is pulled forward over an obstacle, the obstacle can slide against the front slider  40   a  and/or the frame climber segment  44 . The front slider  40   a  and the frame climber segment  44  can abut and slide over the obstacle, pushing the trailer  12  up above the obstacle as the trailer  12  is pulled forward. The bottom of the frame  14  and/or bed  28  can slide over the obstacle. As the trailer is dragged over an obstacle, the obstacle can contact the wheels  26  below the mid-point, height-wise, of the wheels  26 . (The wheels  26  can extend below the bottom of the frame  14  below the wheel axles  38 .) As the trailer  12  is dragged forward, the wheels  26  can roll over the obstacle and push the trailer  12  up, for example preventing the obstacle from catching between the wheel  26  (above the mid-point, height-wise) and the frame  14 . If the obstacle contacts the trailer  12  between the wheels  26  and not at both wheels, the Obstacle can slide along the rear slider  40   b  at an angle with respect to the bed, for example preventing the trailer from abruptly dropping off the cleared obstacle and delivering an impulse force to the trailer  12  and cargo in the trailer  12 . 
         [0036]    The wheels  26  can be made from nylon. The wheels  26  can have a width of from about 0.25 in, to about 0.75 in., for example about 0.5 in. 
         [0037]    The trailer walls  30  can be open adjacent to the front slider  40   a  and/or rear slider  40   b.  For example, the openings in the trailer wall  30  can allow for drainage of liquids (e.g., rainwater, dirty water from washing the bed) or solids from the cargo area of the trailer  12 . 
         [0038]    The trailer  12  can have one or more anchoring tabs  48  attached to and extending from the trailer walls  30  and/or bed  28 . The anchoring tabs  48  can have slots or ports, for example to attach to straps used to strap down cargo to the trailer bed  28  and/or walls  30 . The trailer  12  can have anchoring tabs  48  positioned at diametrically, laterally, and/or longitudinally opposite ends of the cargo area. The anchoring tabs  48  can be positioned at the same and/or varying heights in the trailer  12 . The anchoring tabs  48  can be oriented parallel relative to each other, perpendicular relative to each other, at non-parallel and non-perpendicular angles with respect to each other, or combinations thereof. 
         [0039]    The frame  14  can extend over and in front of the bed  28 . The front end of the frame  14  can terminate as a trailer coupler  50 . The trailer coupler  50  can be a ball, a threaded bolt rotatably attached to the frame  14 , a threaded washer or port (as shown), a rod of the frame  14 , multiple rods, or combinations thereof. The trailer coupler  50  can be configured to attach to the hitch  24 . 
         [0040]    The height from the bottom of the wheels  26  to the bottom of the lower of the frame  14  or bed  28  (as shown in  FIG. 2   f ) can be a frame clearance height  52 . The frame clearance height  52  can be from about 1 in. to about 3 in., for example about 1.5 in. 
         [0041]    The frame  14  can form a coupler extension  54  from the front of the bed  28  to the trailer coupler  50 . The coupler extension  54  can be a gooseneck. The coupler extension  50  can be configured so the height and distance from the coupler  50  can clear the rear flippers  16  of the robot  10 , for example when the trailer  12  is pulled by the robot  10  driving forward and when the trailer  12  is jackknifed (e.g., at a trailer angle of about 120° or −120°) when the robot  10  is driving in reverse. 
         [0042]    The length from the front of the bed  28  or front trailer wall  30  to the coupler  50  can be a coupler extension length  56 . The coupler extension length  56  can be from about 5 in. to about 15 in., for example about 7 in. The coupler extension  54  can be a length of the frame in a gooseneck configuration that can clear the rear flippers  16  when the robot  10  is turning, for example sharply, both clearing the frame&#39;s height, as well as the bed&#39;s distance from the coupler  50 . 
         [0043]      FIGS. 3   a  and  3   b  illustrate that the hitch  24  can have a hitch cover  58 . The hitch cover  58  can cover a hitch frame  60  and/or the actuation components of the hitch  24 , for example as shown in  FIGS. 6   a  through  7   c.  The hitch cover  58  and/or hitch frame  60  can be removably attached to the rear terminal end of the body of the robot  10 . 
         [0044]    The hitch assembly can have a hitch binder cable  62 . The hitch binder cable  62  can connect the hitch  24  to the power and data communication electronics of the remainder of the robot  10 . The binder cable  62  can deliver power to the hitch  24  and send the data signal to release to the hitch  24 . The binder cable  62  can send feedback from the hitch  24  to the robot  10 . The robot  10  can communicate the status (e.g., open, closed, whether attached or not attached to the trailer  12 , the type of trailer  12  perhaps identified by a signal detected from the trailer coupler, the weight of the trailer  12 , the resisting or drag force from the trailer  12 ) of the hitch  24  to the remote control. 
         [0045]    The binder cable  62  can connect to the control system of the robot  10 . The binder cable  62  can plug in to the main body of the robot  10 . The hitch  24  can have a wireless connector and/or direct connector with or instead of the binder cable  62 . The direct connector can plug into the robot  10  (or the robot  10  can have a plug that enters the connector) while attaching the hitch  24  to the robot  10 . The wireless connector can communicate (e.g., via Bluetooth) with the data and/or power systems on the robot  10 . The connectors and/or binder cable can transmit the data transfer to and from the microprocessor that controls the actuator, and for example one or more processors in the robot body. The hitch  24  can have a separate power source (e.g., a hitch battery) than the power source of the remainder of the robot  10 . 
         [0046]    The hitch  24  can have a hitch handle  64 . The hitch handle  64  can be attached to the hitch cover  58  and/or hitch frame  60 . The hitch handle  64  can extend rearward from the hitch frame  60 . 
         [0047]    The hitch  24  can have a hitch receiver  66 . The hitch receiver  66  can extend rearward from the hitch cover  58 . The hitch receiver  66  can have a hitch receiver ring  68  at the rear terminal end of the hitch receiver  66 . The hitch receiver ring  68  can have a receiver port  70 . The hitch receiver port  70  can be partially or completely encircled by the receiver ring  68 . The trailer coupler  50  can attach to the receiver port  70 . 
         [0048]      FIGS. 4   a ,  4   b  and  4   c ′ illustrate that the receiver  66  can have a receiver assembly  71  extending rearward. The receiver assembly  71  can permit three degrees of freedom of rotation between the hitch  24  (and therefore the robot  10 ) and the trailer  12 . The receiver assembly  71  can have a bolt extender  72  threadably attached to the portion of the receiver  66  extending directly from the hitch cover  58 . A locknut  73  can be tightened on the extender  72  against the remainder of the receiver  66  to rotationally fix the extender  72  to the portion of the receiver  66  extending directly from the hitch cover  58 . The rear terminal end of the extender  72  can be the receiver ring  68 . A trailer attachment bolt  74  can extend vertically upward (as shown) or downward from the receiver ring  68 . The trailer attachment bolt  74  can extend short of, to, or past (as shown) the height of the bottom or top of the hitch handle  64 . The trailer attachment bolt  74  can be threaded. 
         [0049]    The trailer attachment bolt  74  can terminate in the receiver ring  68  with a trailer attachment ball  76 . The inner radius of the receiver ring  68  can have a partially spherical shape (i.e., the surface can have a radius of curvature from the center of the ring  68  vertically and horizontally). The attachment ball  76  can rotate in the receiver ring  68  in one (e.g., about a vertical axis, for example if the ball  76  has a ring extending radially that is bound within a horizontal groove in the inner diameter of the receiver ring  68 ), two or three dimensions. The ball  76  can be translationally fixed inside of the receiver ring  68 . The trailer  12  can be attached to the trailer attachment bolt  74 . 
         [0050]      FIG. 4   c ′ illustrates that the receiver  66  can have one or more rollers  78 , for example the receiver top roller  78   a  and the receiver bottom roller  78   b . The receiver top roller  78   a  can be at the front terminal end of the receiver  66 . For example, the receiver top roller  78   a  can be the longitudinal terminus of the receiver  66 . The receiver top roller  78   a  can extend above the top of the receiver body. The receiver bottom roller  78   b  can be longitudinally even with or rear of the receiver top roller  78   a . The receiver bottom roller  78   b  can extend below the bottom of the receiver body. The receiver rollers  78  can be configured to roll against the receiver guides and/or the walls of the receiver channel (shown in  FIGS. 6   a ,  8 , and  9   a  through  9   c.    
         [0051]      FIGS. 5   a  and  5   b  illustrate that the receiver  66  can be actuated to retract, as shown by arrow, the receiver  66  in the direction of the hitch cover  58  and robot  10 . The receiver  66  can be actuated to release and detach from the remainder of the hitch  24 . If the receiver  66  is attached to the trailer  12 , detaching the receiver  66  from the remainder of the hitch  24  can detach the trailer  12  from the robot  10 . The hitch  24  can be actuated through a signal received from a remote control by the robot  10  and, for example, transmitted to the hitch  24  by the robot  10  through the binder cable  62 . 
         [0052]    Instead of or in addition to the receiver ring  68  and/or the bolt  74 , the hitch  24  can have one or more clamping jaws (e.g., a pintle hook), tow pins, balls, lunette rings, or combinations thereof. 
         [0053]      FIGS. 6   a  and  6   b  illustrate that the hitch  24  can have a hitch frame  60  attached to the hitch cover  58 . The hitch frame  60  can be attached to the body of the robot  10 . The hitch  24  can have an actuator  80 , such as a linear actuator that has a motor and acme screw, a ball screw or roller screw, a linear motor, solenoid, or combinations thereof. 
         [0054]    The actuator  80  can be actuated by a signal transmitted by the remote control to the robot  10  and from the robot  10  through the binder cable  62 . The actuator  80  can be actuated by a signal autonomously generated by the robot  10 , for example if the robot  10  detects the trailer  12  and/or robot  10  are motion impaired or translationally or rotationally fixed or that the robot  10  has reached the trailer&#39;s destination, the robot  10  can actuate the actuator  80  to detach the trailer  12  from the robot  10 . 
         [0055]    The actuator  80  can be fixed to a plunger  82 . The hitch  24  can have a plunger channel  84 . The plunger  82  can slidably translate in the plunger channel  84 . The plunger  82  can be attached externally and/or internally (as shown) to an actuator retraction spring  86 . The plunger  82  can have a plunger gasket or plunger seal  88  between the plunger  82  and the wall of the plunger channel  84 . The distal terminal end of the plunger  82  can be a hemispherical dome  90 . The dome  90  can be a ball detent. The dome  90  can have a smooth or textured (e.g., knurled) surface. 
         [0056]    The hitch  24  can have a receiver channel  92 . The receiver channel  92  can be oriented perpendicular to the plunger channel  84 . The receiver channel  92  and plunger channel  84  can open into each other (i.e., can be in fluid communication with each other). The receiver channel  92  can have sloped receiver guides  94  on the watts of the receiver channel  92 . The receiver guides  94  can guide the receiver  66  into the receiver channel  92  when the receiver  66  is slid into the receiver channel  92 . 
         [0057]    The hitch  24  can have a dome stop pin  96 . The dome stop pin  96  can extend parallel with and into the receiver channel  92 . The distal terminal end of the dome stop pin  96  can be wider than the remainder of the shaft of the dome stop pin  96 . 
         [0058]    The dome stop pin  96  can be encircled by a release spring  98 . The release spring  98  can be a coil spring. A release spring washer  100  can encircle the dome stop pin  96  distal to the release spring  98 . The release spring washer  100  can abut and stop against the widened distal tip of the dome stop pin  96 . The release spring  98  can be biased to expand against the release spring washer  100  when the release spring washer  100  abuts the distal tip of the dome stop pin  96 . 
         [0059]    The receiver  66  can have a dome ramp  102 . The dome ramp  102  can have a flat, angled or a convex curved surface on the front terminal end of the receiver  66  on the side of the receiver  66  fixing the plunger  82 . 
         [0060]    The receiver  66  can have a hitch lock port  104  near the front terminal end of the receiver  66 . The hitch lock port  104  can extend through most or all of the width of the receiver  66 . The hitch lock port  104  can extend parallel with the plunger channel  84 . The hitch lock port  104  can have a diameter equal to or larger than the diameter of the plunger  82 . 
         [0061]    The receiver  66  can have a dome stop pin port  106 . The stop pin port  106  can extend from the front terminal end of the receiver  66  into the hitch lock port  104 . The stop pin port  106  can be at least as wide as the maximum width of the dome stop pin  96 . 
         [0062]    The receiver  66  can be translated, as shown by arrow  108 , into the receiver channel  92 . The front terminal end of the receiver  66  can be slid into the receiver channel  92 , for example against the receiver guides  94 . The dome ramp  102  can press against the dome  90 , for example sliding against and pushing the dome  90  out of the way of the receiver  66  as the receiver  66  translates into the receiver channel  92 . The actuator retraction spring  86  can be biased to contract and pull the plunger  82  away from the receiver channel  92  and the receiver  66 , as shown by arrow  109 . The receiver  66  can be pushed into the receiver channel  92  while the actuator  80  is actuated or not actuated. For example, if the actuator  80  is actuated, the force of receiver  66  can exceed the resistive force caused by friction between the dome  90  and the dome ramp  102 . 
         [0063]    As the receiver  66  is slid into the receiver channel  92 , the dome stop pin port  106  can pass over the stop pin  96 . The stop pin  96  can extend into the hitch lock port  104 . The receiver  66  can abut the release spring washer  100  and compress the release spring  98 , as shown by arrow  110  in  FIG. 6   b.    
         [0064]      FIG. 7  illustrates that the actuator  80  can be actuated, for example, forcing the plunger  82  toward the receiver  66 . The dome  90  and/or distal end of the plunger  82  can translate into the hitch lock port  104 . The dome  90  can abut and stop against the dome stop pin  96  in the hitch lock port  104 . The plunger  82  positioned in the hitch lock port  104  can fixedly attach the receiver  66  to the remainder of the hitch  24 . When the receiver  66  is in the receiver channel  92  and the plunger  82  is in the hitch lock port  104 , the receiver  66  can compress the release spring  98 . 
         [0065]      FIG. 8  illustrates that the actuator  80  can be deactivated, for example when the actuator  80  is turned off and/or the hitch  24  loses power (e.g., the robot  10  loses power, for example if the robot battery dies). The actuator retraction spring  86  can be biased to pull the plunger  82  and the actuator  80  out of the hitch lock port  104  and away from the receiver  66 . With the actuator  80  deactivated, the actuator retraction spring  86  can translate the plunger  82 , as shown by arrow  109 . 
         [0066]    The release spring  98  can longitudinally expand, as shown by arrow  114 . The release spring  98  can press the release spring washer  100  against the front terminal end of the receiver  66 . The release spring washer  100  can translate along the dome stop pin  96  and push the receiver  66 . The receiver  66  can translate, as shown by arrow  116 , along and out of the receiver channel  92 . The receiver  66  can exit the receiver channel  92  entirely. The receiver  66  can release and separate from the remainder of the hitch  24 . 
         [0067]    The hitch  24  can have a manual fixation element, such as a pin, bolt or other mechanical element or combinations thereof, to fix the plunger  80  in a position in the hitch lock port  104  or out of the hitch lock port  104 . For example, the plunger  80  can be fixed in the hitch lock port  104  during shipping of the hitch  24  or to keep the trailer attached to the robot  10  in case of loss of power. 
         [0068]      FIG. 9   a  illustrates that the hitch  24  can have an actuator case  118 . The actuator  80  can be unactuated. The actuator  80  can be partially or completely in the actuator case  118 . The hitch plunger  82  can abut and/or be adjacent to the actuator case  118 . 
         [0069]    The dome stop pin  96  can be attached to a dome stop pin backing  120 . The release spring  98  can be substantially uncompressed between the dome stop pin backing  120  and the release spring washer  100 . 
         [0070]    The receiver  66  can be removed entirely from the receiver channel  92  or inserted into the receiver channel  92  but not fixed to the remainder of the hitch  24 . 
         [0071]      FIG. 9   b  illustrates that the actuator retraction spring  86  can be compressed and the actuator  80  can be actuated. The plunger  82  can press against the side of the receiver  66 , for example on the dome ramp  102 . 
         [0072]      FIG. 9   c  illustrates that the receiver  66  can be translated forward into the receiver channel  92 , as shown by arrow. The receiver  66  can compress the release spring  98  between the receiver  66  and the dome stop pin backing  120 . 
         [0073]    The actuator  80  can be actuated, pushing the actuator  80  and plunger  82  toward the receiver  66 . The receiver  66  can be translated forward into the receiver channel  92  while the actuator  80  is actuated. For example, the plunger  82  can slide and snap into the hitch lock port  104  as the receiver  66  is pushed into the receiver channel  92 , locking the receiver  66  into the receiver channel  92 . 
         [0074]      FIGS. 10   a  through  10   d  illustrate that the actuator  80  can be or have a rotational electric motor. The motor can be attached to a transmission to transfer the power from the motor to the plunger  80 . The transmission can have an actuator gear or screw  122 , such as an acme screw, roller screw, ball screw, a gear or gearing (e.g., combination of gears), or combinations thereof attached directly to the motor. The actuator screw or gear  122  can be treadably attached to an actuator arm  124 . The actuator arm  124  can be attached to the plunger  82 . When the motor rotates, the actuator screw and/or gear  122  can rotate. When the actuator screw  122  rotates, the actuator arm  124  can translate along the length of the screw  122 . When the actuator arm  124  translates, the plunger  82  can translate. The motor can be rotated in either direction. The motor can control the translation toward and away from the receiver channel  92  (and the hitch lock channel when the receiver  66  is in the receiver channel  92 ). The motor and gear can be oriented parallel to the plunger channel  84 . The rotational electric motor, actuator gear  122  and actuator arm  124  can function as a linear actuator. 
         [0075]    The hitch  24  can have a hitch lid  126 . The hitch lid  126  can be removably attached to the hitch cover  58  and/or hitch frame  60 . The hitch  24  can have a hitch cover gasket  128 . The hitch cover gasket  128  can seal (e.g., water-tight and/or air-tight) the hitch lid  126  against the hitch cover  58  and/or frame  60  when the hitch lid  126  is attached to the remainder of the hitch  24 . 
         [0076]    The hitch  24  can have one or more (e.g., four as shown) robot attachment bolts  130 . The robot attachment bolts  130  can attach to the hitch cover  58  and/or hitch frame  60 . The robot attachment bolts  130  can attach to the robot body and/or the hitch handle  64 . 
         [0077]    More than one range or example of quantities can be provided for a characteristic as alternative contemplated ranges and examples. Elements, characteristics and configurations of the various variations of the disclosure can be combined with one another and/or used in plural when described in singular or used in plural when described singularly.