Shroud support mechanism for robotic ground care machine

Abstract

A robotic work vehicle includes a chassis and a shroud that covers the chassis. The vehicle includes an elongated member with a distal mount end that is attached to the shroud. A fixture couples the elongated member to the chassis. The fixture includes a cupped member coupled to the elongated member and located over a beveled void in the fixture. A biasing member pushes the cupped member into the beveled void causing the elongated member to be biased to a home position. A linkage couples the elongated member to the fixture. The linkage includes a rotating interface that allows the elongated member to rotate relative to the chassis in response to a horizontal displacement between the shroud and the chassis. The linkage includes a linear interface that allows the elongated member to move vertically in response to a vertical displacement between the shroud and the chassis.

Description

SHROUD SUPPORT MECHANISM FOR ROBOTIC GROUND CARE MACHINERELATED PATENT DOCUMENTS

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 609,701, filed on December 13, 2023, which is incorporated herein by reference in its entirety.SUMMARY

[0002] The present disclosure is directed to a shroud support mechanism of an autonomous ground care machine. In one embodiment, a robotic work vehicle includes a chassis and a shroud that covers the chassis. The vehicle includes an elongated member with a distal mount end that is attached to the shroud. A fixture couples the elongated member to the chassis. The fixture includes a cupped member coupled to the elongated member and located over a beveled void in the fixture. A biasing member pushes the cupped member into the beveled void causing the elongated member to be biased to a home position. A linkage couples the elongated member to the fixture. The linkage includes a rotating interface that allows the elongated member to rotate relative to the chassis in response to a horizontal displacement between the shroud and the chassis. The linkage includes a linear interface that allows the elongated member to move vertically in response to a vertical displacement between the shroud and the chassis.

[0003] In another embodiment, a robotic work vehicle includes a chassis and a shroud that covers the chassis. The vehicle includes an elongated member with a major axis and distal mount end attached to the shroud. A fixture couples the elongated member to the chassis and a linkage couples the elongated member to the fixture. The linkage includes a rotating interface that allows the elongated member to rotate relative to the chassis in response to a horizontal displacement between the shroud and the chassis. The linkage includes a linear interface that allows the elongated member to move vertically in response to a vertical displacement between the shroud and the chassis. A resilient member is separate from and between the elongated member and the fixture. The resilient member provides a counteracting force between the elongated member and the fixture in response to the horizontal displacement.

[0004] In another embodiment, a method involves coupling a shroud to a chassis of a robotic work vehicle via an elongated member coupled to a linkage. The linkage includes a rotating interface that allows the elongated member to rotate relative to the chassis in response to a horizontal displacement between the shroud and the chassis. The linkage also includes a linear interface that allows the elongated member to move vertically in response to a vertical displacement between the shroud and the chassis. In response to the horizontal displacement, the method further comprises biasing the elongated member to a home position via: a cupped member coupled to the elongated member and centered over a beveled void in a fixture, the fixture coupled to the chassis; and a biasing member that pushes the cupped member into the beveled void.

[0005] These and other features and aspects of various embodiments may be understood in view of the following detailed discussion and accompanying drawings.BRIEF DESCRIPTION OF THE DRAWINGS

[0006] The discussion below makes reference to the following figures, wherein the same reference number may be used to identify the similar / same component in multiple figures. The drawings are not necessarily to scale.

[0007] FIGS. 1 and 2 are perspective views of a ground care vehicle according to various example embodiments;

[0008] FIG. 3 is a cutaway view of the ground care vehicle shown in FIGS. 1 and 2.

[0009] FIG. 4 is a cutaway view of a shroud linkage assembly according to an example embodiment;

[0010] FIG. 5 is a top view of the shroud linkage assembly shown in FIG. 4;

[0011] FIGS. 6 and 7 are graphs conceptually illustrating behavior of a resilient member according to another example embodiment;

[0012] FIG. 8 is a perspective view of the shroud linkage assembly shown in FIG. 4;

[0013] FIG. 9 is a perspective view of a fixture of the shroud linkage assembly according to an example embodiment;

[0014] FIG. 10 is a block diagram of an apparatus according to an example embodiment; and

[0015] FIG. 11 is a flowchart showing a method according to an example embodiment.DETAILED DESCRIPTION

[0016] In the following detailed description of illustrative embodiments, reference is made to the accompanying figures of the drawing which form a part hereof. It is to be understood that other equivalent embodiments, which may not be described and / or illustrated herein, are also contemplated.

[0017] The present disclosure relates generally to ground care machines, which may be variously referred to herein as ground care vehicles, ground maintenance machines, ground maintenance vehicles, and the like. Ground care machines, such as lawn and garden machines, are known for performing a variety of tasks. For instance, powered lawn mowers are used by both homeowners and professionals alike to maintain grass areas within a property or yard. The same or different machines may be used for maintenance on the turf areas (and sometimes away from turf), performing operations such as debris collection, spraying, dethatching, edging, rolling, towing, snow / ice treatment and removal, etc.

[0018] Embodiments of the present disclosure relate to features of a robotic work vehicle, such as an autonomous ground maintenance machine. Generally, an autonomous machine may perform a defined set of operations without human input. The autonomous inputs are generated by a computer processor and cause and / or effect a physical action performed by the machine. One example of autonomous operation is autonomous navigation, where the machine can maneuver around a work region without user input, or with minimal user input (e.g., initial placement and initiating a start command). Robotic work vehicles do not need to be fully autonomous, e.g., may be remote controlled by a human, however some actions may still be autonomously guided or halted based on sensor inputs to the machine. For example, a bump sensor may detect an obstacle that may not bevisible by the operator, and the machine can autonomously take an action based on this, e.g., stop moving, alert the operator, back up and re-route, etc.

[0019] A robotic work vehicle may have a variety of sensors to interact with its environment, particularly for autonomous vehicles. Those sensors include cameras, proximity sensors, bump sensors, inertial navigation sensors, wheel speed encoders, geolocation sensors, etc. The work vehicle may use the sensors to halt operation if an event is detected which could damage the machine or cause the machine to damage something else. For example, if the machine detects (e.g., via an accelerometer) that it is oriented (e.g., tilted) such that a cutting blade or other turf cutter is exposed, then the power to the cutting blade may be cut off as a precaution.

[0020] In the following enclosure, a shroud support mechanism is described that can allow relative movement of a shroud (or other body cover) of a robotic work vehicle, e.g., due to hitting a boundary or obstacle such that a bump sensor can detect the impact. In response to bump detection, the work vehicle may back away from the obstacle but may continue working, e.g., attempt to maneuver around the obstacle. The support mechanism can allow a lift sensor to detect if the shroud is being lifted from a chassis, e.g., by a bystander (e.g., person proximate the vehicle) attempting to lift up the vehicle. In this case, a work implement (e.g., turf cutting blade) may be disabled. In this context, the disabling may include stopping the work implement if it is moving as well as stopping wheels and / or other motive components. Even if the work implement or machine is not moving when a lift is detected, a shutoff may be activated (e.g., power cutoff relay) to prevent the movement of the machine and / or preventing the work implement from inadvertently being activated while the lift condition is detected. In some embodiments, a disabling or warning device may be activated (e.g., a shaft brake, flashing light) in the event the lift condition is detected.

[0021] In FIGS. 1 and 2, perspective views show a robotic work vehicle 100 according to one or more embodiments. As best seen in FIG. 2, the robotic work vehicle 100 includes a chassis 104 with a motor coupled to drive wheels 101 that propels the work vehicle 100. The vehicle 100 also has front wheels 103 that can be used for steering, e.g., actively controlled. In other embodiments, the front wheels 103 may freely rotate, e.g., caster wheels, such that the vehicle 100 is steered by differential rotation of the drivewheels 101. A work implement (not seen in this view) performs work on or near the ground such as cutting, scraping, spraying, aerating, etc. In this example, the work implement includes a rotary, turf-cutting, blade underneath the chassis 104 that faces the ground and is driven by a rotating electric motor to cut grass.

[0022] A shroud 102 covers the chassis 104 and, among other things, protects internal components from damage from water, dust, flying debris, etc. Mounted near four outward comers of the chassis 104 are linkage assemblies 106 that couple the shroud 102 to the chassis 104. More or fewer linkage assemblies 106 can be used in some embodiments. In FIG. 2, the linkage assemblies 106 are concealed by covers 107, which may be flexible waterproof covers that keep out dirt and moisture. The linkage assemblies 106 will be described in greater detail further below. In FIG. 3, a cutaway view shows details of two linkages 106 installed between the shroud 102 and the chassis 104.

[0023] In reference again to FIG. 1, arrows indicate a longitudinal direction 110, a vertical direction 111, and a lateral direction 112. Generally, these three directions 110-112 are defined relative to the work vehicle 100 and are orthogonal to each other. The longitudinal direction 110 corresponds to direction the vehicle 100 moves when going in a forward or reverse straight line. The longitudinal direction 110 may also be referred to as a down-path direction. The lateral direction 112 is aligned with the axles of the drive wheels 101, and may also be referred to as a transverse or cross-path direction. The vertical direction 111 is normal to the ground in which the work vehicle 100 is positioned, and may be aligned with or slightly offset from the gravitational vector depending on whether the work vehicle 100 is on level ground or is on a slope.

[0024] The work vehicle 100 is designed so that the linkage assemblies 106 provide some amount of relative motion between the shroud 102 and the chassis 104. This relative motion allows the shroud 102 to move relative to the vehicle in the event the work vehicle 100 bumps / impacts an obstacle. This relative motion can soften the impact to the chassis 104 and provide time for a navigation controller to detect the impact and back up the vehicle or otherwise deal with the obstacle. The relative vertical movement can also prevent the shroud 102 from getting stuck on obstacles (e.g., rocks, soil mounds) that are slightly larger than the shroud-to-ground clearance. By integrating one or more sensors into the linkage assemblies 106, the displacement of the shroud 102 relative to the chassis104 can be detected and used for lift detection independently of bump detection. If a lift is detected, this may be indicative that a bystander is attempting to lift the vehicle by the shroud, in which case vehicle operations are stopped.

[0025] In FIG. 4, cutaway side view shows a linkage assembly 400, which corresponds to at least one of the linkage assemblies 106 shown in FIGS. 1 and 2. The linkage assembly 400 includes an elongated member 402 (also referred to as a shaft, comprising a distal mount end 404 that attaches to the shroud 102. A fixture 406 couples the elongated member 402 to the chassis 104. The fixture 406 includes a cupped member 408 coupled to the elongated member 402 and located over a beveled void 410 in the fixture 406. The void 410 may also be understood to be a seat, chamfered hole, etc., which interfaces with the cupped member 408. A biasing member 412 (e.g., compression coil spring) pushes the cupped member 408 into the beveled void 410 causing the elongated member 402 to be biased to a home (centered) position, which is the position shown in FIG. 4.

[0026] The linkage assembly 400 includes a linkage 414 that couples the elongated member 402 to the fixture 406. The linkage 414 may also be referred to as a moveable interface, joint, junction, or coupler. The linkage 414 includes a rotating interface 416 that allows the elongated member 402 to rotate relative to the chassis 104 in response to a horizontal displacement 418 between the shroud 102 and the chassis 104. A linear interface 420 allows the elongated member 102 to move vertically in response to a vertical displacement 422 between the shroud and the chassis. The fixture 406 couples the linkage 414 to the chassis 104 via the linkage 414.

[0027] In this example, the rotating interface 416 includes a ball 416a rotatably disposed within a socket 416b and the linear interface 420 comprises a void through the ball 416a that allows the elongated member 402 to slide through the ball 416a. Note that the term “ball” is not meant to imply that the component is fully spherical. As seen in this view, the ball 416a is a partial sphere on an upward facing portion. Note that the socket 416b of the linkage 414 and the void / seat 414 that interfaces with the cupped member 408 are formed into a single structure, also referred to herein as bearing support 422, which is formed integrally with the fixture 406.

[0028] The linkage 400 is also shown with a resilient member 424 that absorbs impacts between the elongated member 402 and the fixture 406 in response to the horizontal displacement 418. The resilient member 424 in this example is an annular or donut shaped part that is slidably attached to the elongated member 402. This allows the resilient member 424 to remain between the elongated member 402 and the fixture 406 during the vertical displacement 422. A sleeve 428 with outer ridges 428a holds the resilient member 424 in place vertically and allows for smooth sliding around the elongated member 402 when the elongated member 402 is displaced upward.

[0029] As best seen in the top view of FIG. 5, the resilient member 424 is separated from the fixture 406 by a first gap 500 over a first angular region 502 and by a second gap 504 different from the first gap 500 over a second angular region 506. The first and second angular regions 502, 506 corresponding to movement directions of the robotic work vehicle. For example, the first angular region 502 corresponds to a forward direction of the robotic work vehicle, and the first gap is smaller than the second gap. In this way, the impact between the resilient member 424 and the fixture 406 will occur after a very short travel when hitting an obstacle while moving in a forward direction, e.g., a heading of about ±45°. In contrast, the travel between the resilient member 424 and the fixture 406 is much larger before impact when hitting an obstacle while reversing.

[0030] Also seen in both FIGS. 4 and 5 are ribs 426 formed integrally with the fixture 406 that extend from an inner surface of the fixture 406 towards the resilient member 424 along the first angular region 502. The first gap 500 is measured between distal ridges of the ribs 426 and the resilient element 426, and may be zero in some embodiments. The ribs 426 cause a local deformation of the resilient element 424 when contact is first made, and then the deformation is spread more widely around part of the resilient element 424 as forces increase. This allows for a non-linear reaction force from the resilient element 424, e.g., more gradual at the start and then increasing as deformation increases. Also seen in FIG. 5 are voids 424a within the resilient member 424 that further allow tuning of the reaction force profile of the resilient member 424.

[0031] In FIGS. 6 and 7, graphs illustrate how the arrangement of the resilient element 424 and fixture 406 can affect impacts in different directions, e.g., forward and reverse impacts. In FIG. 6, a measured curve shows forces of a forward impact (that is, animpact that occurs when the machine is moving in a forward direction) that occurs at time 600, which generates an initial force peak 601 from a centering forces asserted by the cupped member 408 and biasing member 412. After breaking the centering force, the transmitted force drops until the resilient member 424 engages the fixture 406, seen at part 602 of the curve. Mid-impact, the bump sensors respond, braking forward travel and resulting in a decay of the force at part 604 of the curve.

[0032] In FIG. 7, a graph shows an estimate of forces occurring in response to a reverse impact (that is, an impact that occurs when the machine is moving in a reverse direction) occurs at time 700. The force profile is similar to what is shown for a forward impact in FIG. 6, with some differences. First, the change in slope of the counteracting force is lower due to the lower speed of the machine in reverse compared to moving forward. Thus, the centering force represented by peak 702 will still reach a similar maximum value as peak 601, but reaches the peak 702 more slowly.

[0033] Another difference in the reverse impact curve compared to the forward curve is a delay 704 before the resilient element 424 contacts the fixture 406 due to gap 504. If the unit can respond (e.g., stop or change direction) in time, the machine may move forward again within the delay 704 period resulting in no subsequent force peak 706. If the machine cannot respond in time, resilient element 424 contacts the fixture 406, and peak 706 represents the counteracting force of the resilient member. Note that the lower maximum force of peak 706 compared to peak 602 is due to the slower speed in reverse. The delay of a counteracting force peak 706 due to the gap 504 can reduce turf wear during occasions when the machine hits an obstacle going forward and performs a number of backwards movements in order to get around the obstacle.

[0034] In reference again to FIG. 4, the elongated member 402 includes a second distal end 430 opposite the mounting distal end 404. A sensor 432 (e.g., proximity sensor) detects movement of the second distal end 404 vertically (direction 422) away from the sensor 432. In this example, the elongated member 402 includes a sensed element 434 (e.g., a sensor target) at the second distal end 430, e.g., where the sensor 432 is a proximity sensor that detects a proximity of the sensed element 434. In one embodiment, the sensor 432 is a Hall-effect proximity sensor and the sensed element 434 is a magnet. In other embodiments, the sensor 432 is configured to emit a signal (e.g., optical, radio frequency,ultrasonic) and detect a reflected signal back from the sensed element 434, which is configured as a reflector, e.g., optical reflector. Other types of proximity sensors include capacitive sensors that detect a change in local capacitance due to a nearby sensed element.

[0035] As seen in FIG. 4, the sensed element 434 has a dimension 436 normal to the vertical displacement 422 such that the proximity is detected by the sensor 432 during the rotation of the elongated member 402 that results in a horizontal offset between a center of the sensed element 434 and a center of the sensor 432. The oversized dimension 436 helps ensure that when the elongated member 402 rotates absent any vertical displacement 422, the sensor 432 does not signal that the shroud 102 has lifted relative to the chassis 104. In other words, this allows the collision events that result in horizontal displacement 418 to be decoupled from lifting events that result in the vertical displacement 422. This decoupling ensures that the proximity detector does not detect the rotation of the elongated member 402 as a lift event absent the vertical displacement. A separately located bump sensor (e.g., on front and / or rear of the vehicle) between the shroud and chassis can provide signals that measure the horizontal displacement 422.

[0036] In FIG. 8, a perspective view shows details of the linkage assembly 400. As evident in this view, the fixture 406 is bowl-shaped, with the resilient element 424 being centered inside the bowl in home position of the elongated member 402. The resilient member 424 can remain in this location when the elongated member 402 moves vertically in response to a lifting event, such that impacts can be absorb for an event that includes both lifting of the shroud and an impact. Also note that the sensed element 434 includes a two-piece split housing that assembles around the distal end 430 of the elongated member 402 (best seen in FIG. 4).

[0037] In FIG. 9, a perspective view shows details of the fixture 406 according to an example embodiment. The ribs 426 can be seen unobstructed in this view. Further, top ribs 900 and bottom ribs 902 are shown that extend from the void 410 and have tapers that center the cupped member 408 due to an axial compression force applied by the biasing member 412 (see FIG. 4). By forming these tapered surfaces as ribs 902, 904, the interface between the void 410 and the cupped member 408 may be less susceptible to the effects of foreign matter that enters the inside of the fixture 406.

[0038] In FIG. 10, a block diagram shows electronic components of an apparatus 1000 according to an example embodiment. The apparatus 1000 is a robotic work machine, such as an autonomous ground care machine. The apparatus 1000 includes one or more circuit boards 1002 that house electronic components, such as computer processing circuits, power conditioning and management circuits, sensor signal processing circuits, motor controllers, etc. The processing circuits are represented by System on a Chip (SoC) 1004, which combines components such as central processing units (CPUs), memory, input-output busses, power management, network interfaces, etc., into a single package. These SoC components may be provided in separate packages in some embodiments.

[0039] The SoC 1004 is programmable by computer instructions 1003 that may be embodied as any combination fixed logic (e.g., field programmable gate array, or FPGA), firmware, and software. The instructions 1003 include functional modules such as a navigation / work module 1006 that governs machine operations when moving and / or working in a work region. This module 1006 may access stored maps and work instructions, interpret inputs from sensors 1010-1011, and utilize controller logic to activate electro-mechanical devices such as one or more work implement motors 1014 and one or more drive motors 1016. The instructions 1003 include a shutoff module 1008 that determines whether circuitry that affects the work implement motor 1014 should be set to stop the work implement while a lift condition is detected.

[0040] A motor controller 1018 facilitates driving the motors 1014, 1016, e.g., by taking a digital input from SoC 1004 and converting it to an analog output, e.g., an electrical current. Note that the embodiments described herein need not use electrical motors and actuators. For example, internal combustion, hydraulic, and / or pneumatic motors may be used instead or in addition to electric motors. Nonetheless, such nonelectric motors may still be controlled via the SoC 1004 by electric means, e.g., valves, relays, fuel injectors / throttles, etc.

[0041] The apparatus includes one or more vertical displacement sensors 1010 that are integrated into a shroud-to-chassis linkage as previously described. The vertical displacement sensors 1010 provide either a binary or multivariable (e.g., integer from 0- 255) indication of shroud-to-chassis vertical displacement at a location on the apparatus.The apparatus 1000 may have multiple such linkages (e.g., four linkages) but not all of the linkages need be equipped with vertical displacement sensors 1010.

[0042] For example, a machine with two or more linkage located between the shroud and the chassis at different first and second locations may have vertical displacement sensors 1010 respectively detect two or more vertical displacements at the different first and second locations, e.g., different corners of the vehicle. Detection of the vertical displacement may involve combining the two or more vertical displacements. For example, if the vertical displacement sensors 1010 are configured to produce a binary signal (e.g., 0=not lifted, l=li fted), then the combination may involve a logical operation such as AND, OR and / or a mathematical operation, e.g., sum of the number of lift detections. If the vertical displacement sensors 1010 are configured to produce a measurement of displacement (e.g., an integer or floating point value within a range), then the combination may involve averaging, using a maximum one of the values, etc.

[0043] In some embodiments, the apparatus includes one or more horizontal displacement sensors 1011 that are integrated into or located away from the shroud-to- chassis linkage as previously described. For example, one or two horizontal displacement sensor 1011 may be located on a front side of the work machine between the shroud and chassis such that they are mechanically and electrically separate from the linkages and associated lift sensor. The horizontal displacement sensors 1011 provide either a binary or multivariable (e.g., integer from 0-255) indication of shroud-to-chassis horizontal displacement at a location on the apparatus. Similar sensors 1011 may be placed at the rear of the work machine.

[0044] Similar to the vertical displacement sensors 1010, outputs from two or more horizontal displacement sensors 1011 may be combined, such as a logical combination of binary outputs or statistical combination of measurement values. Further, the measurements of horizontal and vertical displacement from the different sensors can be combined. For if values of both horizontal and vertical displacement are detected, then the measurements can be combined to form vector that represents a total displacement and / or an angle of displacement. This can provide a more detailed profile of particular lift / impact events, allowing for a more varied response.

[0045] The readings obtained from the vertical displacement sensors 1010 and horizontal displacement sensors 1011 can be combined with readings from other sensor 1012, such as an accelerometer, inertial measurement unit, gyroscope, proximity detector, etc. This can provide a more detailed representation of bump / lift events, and can also be used to cross check sensor readings, e.g., determine anomalous readings due to a sensor malfunction. These measurements and characterizations can be used by the shutoff module to pause, stop, disable, a mechanism such as a cutting implement. The measurements and characterizations can also be used by the navigation / work module 1006, e.g., to detect obstacles, stuck conditions, machine malfunctions, etc. The other sensors 1012 may also include navigation sensors such as cameras, radar, LIDAR, RTK, contact sensors, proximity sensors, beacon detectors, boundary wire detectors, etc., that are used by the navigation / work module 1006.

[0046] In view of the above, it will be readily apparent that the functionality of the controllers of the system may be implemented in any manner known to one skilled in the art. For instance, the memory may include any volatile, non-volatile, magnetic, optical, and / or electrical media, such as a random-access memory (RAM), read-only memory (ROM), non-volatile RAM (NVRAM), electrically-erasable programmable ROM (EEPROM), flash memory, and / or any other digital media.

[0047] The processors used in the controllers may include any one or more of a microprocessor, a controller, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA), and / or equivalent discrete or integrated logic circuitry. In some embodiments, the processor may include multiple components, such as any combination of one or more microprocessors, one or more controllers, one or more DSPs, one or more ASICs, and / or one or more FPGAs, as well as other discrete or integrated logic circuitry. The functions attributed to the controller and / or processor herein may be embodied as software, firmware, hardware, or any combination of these. Certain functionality of the controller may also be performed in the cloud or other distributed computing systems operably connected to the processor.

[0048] In FIG. 11, a flowchart illustrates a method according to an example embodiment. As indicated in block 1100, a shroud is coupled to a chassis of a robotic work vehicle via an elongated member coupled to a linkage. The linkage includes a rotatinginterface that allows the elongated member to rotate relative to the chassis in response to a horizontal displacement between the shroud and the chassis. The linkage also includes a linear interface that allows the elongated member to move vertically in response to a vertical displacement between the shroud and the chassis.[0049J As indicated at block 1101, the linkage is maintained at a home position when no outside forces are acting between the shroud and the chassis. When a horizontal displacement occurs (block 1102 returns ‘yes’) any impacts will be absorbed using differing profiles depending on whether the machine is going forward or not (e.g., in reverse), as indicated by blocks 1103-1105. For both cases, the absorption is provided by a resilient member separate from and between the elongated member and a fixture coupled to or part of the chassis. Also for both cases, after the impact has occurred and no more horizontal forces are acting on the shroud, the elongated member is biased 1106 to a home position. The biasing is driven a cupped member coupled to the elongated member, and a biasing member that pushes the cupped member into a beveled void in the fixture where it is centered.

[0050] Whether or not a horizontal displacement occurs, a vertical displacement is detected, e.g., via a sensor, as indicated by block 1107. A work implement of the robotic work vehicle is stopped 1108 in response to the vertical placement, and the does not start again until the vertical displacement is removed, e.g., block 1107 returns ‘no.’ During the loop between blocks 1107 and 1108, the mechanical components will stop providing the impact absorption and home position return as shown in blocks 1104-1105.

[0051] While the present disclosure is not so limited, an appreciation of various aspects of the disclosure will be gained through a discussion of the specific illustrative aspects provided below. Various modifications of the illustrative aspects, as well as additional aspects of the disclosure, will become apparent herein.

[0052] Example l is a robotic work vehicle, comprising: a chassis and a shroud that covers the chassis; an elongated member comprising a distal mount end attached to the shroud; and a fixture that couples the elongated member to the chassis. The fixture comprises: a cupped member coupled to the elongated member and located over a beveled void in the fixture; and a biasing member that pushes the cupped member into the beveled void causing the elongated member to be biased to a home position. The vehicle furthercomprises a linkage that couples the elongated member to the fixture. The linkage comprises: a rotating interface that allows the elongated member to rotate relative to the chassis in response to a horizontal displacement between the shroud and the chassis; and a linear interface that allows the elongated member to move vertically in response to a vertical displacement between the shroud and the chassis.

[0053] Example A2 includes the robotic work vehicle of example Al, wherein the rotating interface comprises a ball rotatably disposed within a socket. Example A3 includes the robotic work vehicle of example A2, wherein the linear interface comprises a void through the ball that allows the elongated member to slide through the ball.

[0054] Example A4 includes the robotic work vehicle of any previous A example, further comprising a resilient member that absorbs impacts between the elongated member and the fixture in response to the horizontal displacement. Example A5 includes the robotic work vehicle of example A4, wherein the resilient member is slidably attached to the elongated member allowing the resilient member to remain between the elongated member and the fixture during the vertical displacement. Example A6 includes the robotic work vehicle of example A4, wherein the resilient member is separated from the fixture by a first gap over a first angular region and by a second gap different from the first gap over a second angular region different from the first angular region, the first and second angular region corresponding to movement directions of the robotic work vehicle. Example A7 includes the robotic vehicle of example A6, wherein the first angular region corresponds to a forward direction of the robotic work vehicle, and the first gap is smaller than the second gap. Example A8 includes the robotic vehicle of example A7, wherein the fixture comprises ribs that extend towards the resilient element, the first gap being measured between distal ridges of the ribs and the resilient element.

[0055] Example A9 includes the robotic work vehicle of any previous A example, wherein the elongated member comprises a second distal end opposite the mounting distal end, the sensor detecting movement of the second distal end vertically away from the sensor. Example A10 includes the robotic work vehicle of example A9, wherein the elongated member comprises a sensed element at the second distal end, and wherein the sensor comprises a proximity sensor that detects a proximity of the sensed element. Example Al 1 includes the robotic work vehicle of example A10, wherein the sensedelement has a dimension normal to the vertical displacement such that the proximity is detected by the proximity sensor during the rotation of the elongated member. Example A12 includes the robotic work vehicle of example Al l, wherein the proximity detector does not detect the rotation of the elongated member as a lift event absent the vertical displacement. Example A13 includes the robotic work vehicle of example A10, wherein the proximity sensor comprises a Hall effect sensor and the sensed element comprises a magnet. Example A14 includes the robotic work vehicle of example A10, wherein the proximity sensor comprises an optical transceiver and the sensed element comprises an optical reflector.[00561 Example Al 5 includes the robotic work vehicle of any previous A example, further comprising: a sensor that detects the vertical displacement; and a controller coupled to the sensor, the controller operable to detect the vertical displacement via the sensor and stop a work implement of the robotic work vehicle in response thereto. Example Al 6 includes the robotic work vehicle of example Al 5, wherein the vertical displacement is due to a bystander lifting the work vehicle by the shroud.

[0057] Example Al 7 includes the robotic work vehicle of any previous A example, wherein the rotating interface allows the elongated member to rotate relative to the chassis in both a longitudinal direction and a lateral direction.

[0058] Example B 18 is a robotic work vehicle, comprising: a chassis and a shroud that covers the chassis; an elongated member comprising a major axis and distal mount end attached to the shroud; a fixture coupled to the chassis; and a linkage that couples the elongated member to the fixture. The linkage comprises: a rotating interface that allows the elongated member to rotate relative to the chassis in response to a horizontal displacement between the shroud and the chassis; and a linear interface that allows the elongated member to move vertically in response to a vertical displacement between the shroud and the chassis; The vehicle further comprises a resilient member separate from and between the elongated member and the fixture, the resilient member providing a counteracting force between the elongated member and the fixture in response to the horizontal displacement.

[0059] Example B 19 includes the robotic work vehicle of example B 18, wherein the resilient member is slidably attached to the elongated member allowing the resilient member to remain between the elongated member and the fixture during the verticaldisplacement. Example B20 includes the robotic work vehicle of example B18 or Bl 9, wherein a profile of the counteracting force is different between first and second directions of the robotic work vehicle .Example B21 includes the robotic vehicle of example B20, wherein the first and second directions are navigated at different speeds by the robotic vehicle.

[0060] Example B22 includes the robotic work vehicle of any previous B example, wherein the resilient member is separated from the fixture by a first gap over a first angular region and by a second gap different from the first gap over a second angular region different from the first angular region, the first and second angular region corresponding to movement directions of the robotic work vehicle. Example B23 includes the robotic vehicle of example B22, wherein the first angular region corresponds to a forward direction of the robotic work vehicle, and the first gap is smaller than the second gap.

[0061] Example B24 includes the robotic vehicle of example B23, wherein the fixture comprises ribs that extend towards the resilient element, the first gap being measured between distal ridges of the ribs and the resilient element.

[0062] Example C25 is method, comprising: coupling a shroud to a chassis of a robotic work vehicle via an elongated member coupled to a linkage, the linkage comprising: a rotating interface that allows the elongated member to rotate relative to the chassis in response to a horizontal displacement between the shroud and the chassis; and a linear interface that allows the elongated member to move vertically in response to a vertical displacement between the shroud and the chassis; and in response to the horizontal displacement, biasing the elongated member to a home position via: a cupped member coupled to the elongated member and centered over a beveled void in a fixture, the fixture coupled to the chassis; and a biasing member that pushes the cupped member into the beveled void. Example C26 includes the method of example C25, further comprising: detecting the vertical displacement via a sensor; and stopping a work implement of the robotic work vehicle in response thereto.

[0063] Example D27 is a method, comprising: coupling a shroud to a chassis of a robotic work vehicle via an elongated member coupled to a linkage, the linkage comprising a rotating interface that allows the elongated member to rotate relative to the chassis in response to a horizontal displacement between the shroud and the chassis and a linearinterface that allows the elongated member to move vertically in response to a vertical displacement between the shroud and the chassis; in response to the horizontal displacement due to a first impact occurring when the robotic work vehicle moves in a forward direction, absorb the first impact via a resilient member according to a first force profile, the resilient member separate from and between the elongated member and a fixture coupled to or part of the chassis; and in response to the horizontal displacement due to a second impact occurring when the robotic work vehicle moves in a reverse direction, absorb the second impact via the resilient member according to a second force profile different from the first profile.[00641 Example D28 includes the method of example D27, further comprising: detecting the second impact via a bump sensor; and within a predetermined time from detecting the impact, stopping or changing direction of a motion of the robotic work vehicle in response thereto, wherein the resilient member provides no or minimal absorption of the second impact during the predetermined time. Example D29 includes the method of example D28, wherein a forward speed of the robotic work vehicle is greater than a reverse speed of the robotic work vehicle, and wherein the resilient member provides absorption of the first impact in a response time less than the predetermined time.

[0065] It is noted that the terms “have,” “include,” “comprises,” and variations thereof, do not have a limiting meaning, and are used in their open-ended sense to generally mean “including, but not limited to,” where the terms appear in the accompanying description and claims. Further, “a,” “an,” “the,” “at least one,” and “one or more” are used interchangeably herein. Moreover, relative terms such as ’’left,” “right,” “front,” “fore,” “forward,” “rear,” “aft,” “rearward,” “top,” “bottom,” “side,” “upper,” “lower,” “above,” “below,” “horizontal,” “vertical,” and the like may be used herein and, if so, are from the perspective shown in the particular figure, or while the machine is in an operating configuration. These terms are used only to simplify the description, however, and not to limit the interpretation of any embodiment described. As used herein, the terms “determine” and “estimate" may be used interchangeably depending on the particular context of their use, for example, to determine or estimate a position or pose of a vehicle, boundary, obstacle, etc.

[0066] Further, it is understood that the description of any particular element as being connected to or coupled to another element can be directly connected or coupled, or indirectly coupled / connected via intervening elements.

[0067] Unless otherwise indicated, all numbers expressing feature sizes, amounts, and physical properties used in the specification are to be understood as being modified in all instances by the term “about.” Accordingly, unless indicated to the contrary, the numerical parameters set forth in the foregoing specification are approximations that can vary depending upon the desired properties sought to be obtained by those skilled in the art utilizing the teachings disclosed herein. The use of numerical ranges by endpoints includes all numbers within that range (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5) and any range within that range.

[0068] The various embodiments described above may be implemented using circuitry, firmware, and / or software modules that interact to provide particular results. One of skill in the arts can readily implement such described functionality, either at a modular level or as a whole, using knowledge generally known in the art. For example, the flowcharts and control diagrams illustrated herein may be used to create computer-readable instructions / code for execution by a processor. Such instructions may be stored on a non- transitory computer-readable medium and transferred to the processor for execution as is known in the art. The structures and procedures shown above are only a representative example of embodiments that can be used to provide the functions described hereinabove.

[0069] Note that any components described herein using terms such as “processor,” “controller,” “logic circuit,” “CPU,” or the like may be implemented using a plurality of discrete units operating together. For example, a processer that performs a series of steps or operations may be construed as two or more processors operating cooperatively to perform the steps. Similarly, other processing hardware such as memory and input-output may perform the described functions with multiple discrete units operating cooperatively or being coordinated by another unit, e.g., by a central processor or processors.

[0070] The foregoing description of the example embodiments has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the embodiments to the precise form disclosed. Many modifications and variations are possible in light of the above teaching. Any or all features of the disclosedembodiments can be applied individually or in any combination and are not meant to be limiting, but purely illustrative. It is intended that the scope of the invention be limited not with this detailed description, but rather determined by the claims appended hereto.

Claims

CLAIMS:

1. A robotic work vehicle, comprising: a chassis and a shroud that covers the chassis; an elongated member comprising a distal mount end attached to the shroud; and a fixture that couples the elongated member to the chassis, the fixture comprising: a cupped member coupled to the elongated member and located over a beveled void in the fixture; and a biasing member that pushes the cupped member into the beveled void causing the elongated member to be biased to a home position; and a linkage that couples the elongated member to the fixture, the linkage comprising: a rotating interface that allows the elongated member to rotate relative to the chassis in response to a horizontal displacement between the shroud and the chassis; and a linear interface that allows the elongated member to move vertically in response to a vertical displacement between the shroud and the chassis.

2. The robotic work vehicle of claim 1, wherein the rotating interface comprises a ball rotatably disposed within a socket.

3. The robotic work vehicle of claim 2, wherein the linear interface comprises a void through the ball that allows the elongated member to slide through the ball.

4. The robotic work vehicle of any one of claims 1-3, further comprising a resilient member that absorbs impacts between the elongated member and the fixture in response to the horizontal displacement.

5. The robotic work vehicle of claim 4, wherein the resilient member is slidably attached to the elongated member allowing the resilient member to remain between the elongated member and the fixture during the vertical displacement.

6. The robotic work vehicle of claim 4, wherein the resilient member is separated from the fixture by a first gap over a first angular region and by a second gap different from the first gap over a second angular region different from the first angular region, the first and second angular region corresponding to movement directions of the robotic work vehicle.

7. The robotic vehicle of claim 6, wherein the first angular region corresponds to a forward direction of the robotic work vehicle, and the first gap is smaller than the second gap-8. The robotic vehicle of claim 7, wherein the fixture comprises ribs that extend towards the resilient element, the first gap being measured between distal ridges of the ribs and the resilient element.

9. The robotic work vehicle of any one of claims 1-8, wherein the elongated member comprises a second distal end opposite the mounting distal end, the sensor detecting movement of the second distal end vertically away from the sensor.

10. The robotic work vehicle of claim 9, wherein the elongated member comprises a sensed element at the second distal end, and wherein the sensor comprises a proximity sensor that detects a proximity of the sensed element.

11. The robotic work vehicle of claim 10, wherein the sensed element has a dimension normal to the vertical displacement such that the proximity is detected by the proximity sensor during the rotation of the elongated member.

12. The robotic work vehicle of claim 10 or 11, wherein the proximity sensor does not detect the rotation of the elongated member as a lift event absent the vertical displacement.

13. The robotic work vehicle of any one of claims 10-12, wherein the proximity sensor comprises a Hall effect sensor and the sensed element comprises a magnet.

14. The robotic work vehicle of any one of claims 10-12, wherein the proximity sensor comprises an optical transceiver and the sensed element comprises an optical reflector.

15. The robotic work vehicle of any one of claims 1-14, further comprising: a sensor that detects the vertical displacement; and a controller coupled to the sensor, the controller operable to detect the vertical displacement via the sensor and stop a work implement of the robotic work vehicle in response thereto.

16. The robotic work vehicle of claim 15, wherein the vertical displacement is due to a bystander lifting the work vehicle by the shroud.

17. The robotic work vehicle of any one of claims 1-16, wherein the rotating interface allows the elongated member to rotate relative to the chassis in both a longitudinal direction and a lateral direction.

18. A method, comprising: coupling a shroud to a chassis of a robotic work vehicle via an elongated member coupled to a linkage, the linkage comprising: a rotating interface that allows the elongated member to rotate relative to the chassis in response to a horizontal displacement between the shroud and the chassis; and a linear interface that allows the elongated member to move vertically in response to a vertical displacement between the shroud and the chassis; and in response to the horizontal displacement, biasing the elongated member to a home position via: a cupped member coupled to the elongated member and centered over a beveled void in a fixture, the fixture coupled to the chassis; and a biasing member that pushes the cupped member into the beveled void.

19. The method of claim 18, further comprising: detecting the vertical displacement via a sensor; and stopping a work implement of the robotic work vehicle in response thereto.

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