Ground care machine platform with autonomously controllable features

Abstract

A ground care vehicle has a drive section that moves the ground care vehicle within a work region along a path direction. The vehicle may include autonomous features that automatically activate and deactivate work units, material collectors, and the like. The vehicle may also or instead have autonomous features that enable swapping or work units. The vehicle may operate fully autonomously in some configurations. In other configurations an operator may actively control or monitor some operations while other operations are performed autonomously in cooperation and / or coordination with the operator.

Description

GROUND CARE MACHINE PLATFORM WITH AUTONOMOUSLY CONTROLLABLE FEATURESRELATED PATENT DOCUMENTS

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 527,439, filed on July 18, 2023, which is incorporated herein by reference in its entirety.SUMMARY

[0002] The present disclosure is directed to autonomously controllable features of a ground care machine platform. In one embodiment, a ground care vehicle has a drive section that moves the ground care vehicle within a work region along a path direction. The vehicle includes at least three work units that are arrayed in a pattern that defines a full coverage width of a path of the ground care vehicle. A cross path direction of the full coverage width is defined normal to the path. Associated with each of the three work units are three disengagement units that selectably and individually engage and disengage respective ones of the three work units. The disengagement causes the respective work unit to be disengaged from ground and the engagement causing the respective work unit to be engaged with the ground.

[0003] In another embodiment, a ground care work vehicle has a drive section that moves the ground care vehicle within a work region along a path direction. The vehicle includes at least one collector that collects material from the work region. At least one actuator selectably transitions the at least one collector between collecting and emptying configurations. The vehicle has a controller operatively coupled to the drive section and the at least one actuator. The controller is operable to cause the ground care vehicle to perform, while working within the work region, determine a trigger signal for emptying the at least one collector and navigate the ground care vehicle to a predetermined emptying location. The controller autonomously activates the at least one actuator to transition the at least one collector to the emptying configuration at the emptying location to empty the material.

[0004] In another embodiment, a ground care vehicle has a drive section that moves the ground care vehicle within a work region along a path direction. The vehicle has a first work unit that performs work in the work region. The first work unit is attached to a mounting point of the ground care vehicle. The vehicle has a controller operatively coupled to the drive section and the first work unit. The controller is operable to, while working within the work region, determine a trigger signal for changing the first work unit and navigate the ground care vehicle to a predetermined swapping location. The controller unloads the first work unit at the swapping location and, after unloading the first work unit, loads a second work unit from the swapping location onto the mounting point of the ground care vehicle. The vehicle thereafter performs work in the work region with the second work unit.

[0005] In another embodiment, a ground care vehicle has a drive section that moves the ground care vehicle within a work region along a path direction. The vehicle includes two caster wheel assemblies extending from the drive section in the path direction. The two caster wheel assemblies each include: a caster support arm with a proximal end fixably coupled to the drive section and a distal end opposite the proximal end; and a caster wheel at the distal end of the caster support arm. The vehicle includes a work unit offset from the drive section in the path direction. A center of mass of the work unit is located between the drive section and the caster wheels. The vehicle includes an actuator that moves the work unit relative to the drive section. Retraction of the actuator lowers the caster wheels and raises the work unit. Extension of the actuator raises the caster wheels and lowers the work unit.

[0006] 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

[0007] 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.

[0008] FIG. 1 is a schematic view of a ground care vehicle according to various example embodiments;

[0009] FIGS. 2-9 are schematic views of selective enablement of work units of a ground care vehicle according to an example embodiment;

[0010] FIGS. 10 and 11 are perspective and top views of a ground care vehicle according to other embodiments;

[0011] FIG. 12 is a side view showing emptying configuration of a debris collector according to an example embodiment;

[0012] FIG. 13 is a schematic view of a debris emptying operation according to an example embodiment;

[0013] FIG. 14 is a side view showing a ground care vehicle emptying onto a mobile platform according to an example embodiment;

[0014] FIGS. 15 and 16 are perspective and front views showing mounting of a work vehicle to a ground care vehicle according to an example embodiment;

[0015] FIGS. 17 and 18 are top and side views of a work unit mounting apparatus according to another example embodiment;

[0016] FIGS. 19A-19C are schematic diagrams showing the swapping of work units according to an example embodiment;

[0017] FIGS. 20 and 21 are perspective views showing a ground care vehicle platform with rotary cutter work units according to an example embodiment;

[0018] FIGS. 22 and 23 are perspective and side views of a work unit lifting arrangement according to alternate embodiments;

[0019] FIGS. 24 and 25 are schematic diagrams showing the operation of the lifting arrangement shown in FIGS. 22 and 23;

[0020] FIG. 26 is a block diagram of a system according to an example embodiment; and

[0021] FIGS. 27-30 are flowcharts showing methods according to example embodiments.DETAILED DESCRIPTION

[0022] 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.

[0023] 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 the turf), which may involve performing any combination of operations such as material collection (e.g., plant matter, dirt, golfballs, markers), spraying, dethatching, edging, rolling, towing, snow / ice treatment and removal, etc.

[0024] Embodiments of the present disclosure relate to features of ground maintenance machines that facilitate autonomous functionality. Generally, autonomous functionality may include any operation that can be performed without human input that causes or effects 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).

[0025] In some cases, semi-autonomous functionality can be implemented on human-operated systems, such as where the operator directs the machine to a work location, but the machine autonomously steers within the work region to hold a path (e.g., straight, parallel lines), which the machine can do more accurately than a typical human operator. Other examples of autonomous and semi-autonomous functionality including the automatic activation and deactivation of a work implement (e.g., cutter, sprayer) to limit or shape work within a geometric boundary. Such functionality can be used on a human- operated ground care vehicle to perform autonomous work operations that are coordinated with the operator’s driving inputs to the vehicle. Such a setup can, for example, allow forprecise and selective application of treatment (e g., cutting, water, seeds, fertilizer, pesticides) to turf without requiring setup and precautions often involved in full autonomous navigation.

[0026] In FIG. 1, a block diagram shows details of an apparatus according to one or more embodiments, the apparatus operable as a ground care vehicle. As seen in FIG. 1, the ground care vehicle 100 includes a drive section 102 that moves the ground care vehicle 100 within a work region 104 along a path direction 106. The path direction 106 is generally aligned with a forward or reverse direction of the ground care vehicle 100 when going straight, and tangent to a curved path through a turn. At least three work units 108- 110 are arrayed in a pattern that defines a full coverage width 112 of a path of the ground care vehicle 100. A cross path direction 107 of the full coverage width 112 is defined normal to the path direction. The cross path direction 107 is aligned with a lateral direction of the ground care vehicle 100 as it moves along its path.

[0027] As described elsewhere herein, the work units 108-110 are independently operable mechanisms that perform a specific operation, e.g., cutting, dethatching, rolling, etc. The three work units 108-110 may be any combination of reel cutters, rotary cutters, rollers, brushes, spikers, verti cutters, dethatchers, sprayers etc. All three work units 108- 110 may all have the same function (e.g., cutters) and same configuration. In some embodiments, three work units 108-110 may have different configurations, e.g., cut height, cut width, type of cutter (e.g., reel, rotary), etc. Each work unit 108-110 may have a dedicated electric motor, actuator, or the like (not shown). Accordingly, each work unit 108-110 may have a mechanical and electrical coupling interface to the ground care vehicle 100, e.g., to a central frame 114 and central electrical system 116 of the vehicle 100.

[0028] Associated with each of the three work units 108-110 are three disengagement units 118, 119,120 that selectably and individually engage and disengage respective ones of the three work units. The disengagement causes the respective work unit to be disengaged from the ground and the engagement causing the respective work unit to be engaged with the ground. The engagement and disengagement may involve removing or placing the work unit from / on the ground, and / or may involve stopping orstarting part movements (e.g., blade) such that work that affects the ground can be selectively stopped and started.[00291 InFIG. 1, the disengagement units 118-120 are schematically represented as actuators, and in some embodiments a linear or rotary actuator may lift the respective work units 108-110 on and off the ground. In some cases, an actuator may lift or move some other part of the vehicle 100 different from the work units 108-110 to selectably cause the work units 108-110 to be moved on and off the ground with directly contacting the work units.

[0030] The disengagement units 118-120 may be mechanically or electrically controllable, and may be driven by an electric motor, hydraulic pressure, pneumatic pressure, and / or other means. In autonomous and semi-autonomous embodiments, the disengagement units 118-120 can be electrically controllable even if non-electric actuation is used. An onboard controller (not shown) in such embodiments is operable to send signals to the disengagement units 118-120 in response to a work plan and sensor data (e.g., navigation data).

[0031] As seen in the embodiment of FIG. 1, the first work unit 108 is centrally disposed in the cross path direction 107. The second and third work units 109, 110 are offset in the path direction 106 from the first work unit 108. The first work unit 108 is located between the second and third work units 109, 110 in the cross path direction 107. In this example, the second and third work units 109, 110 are at the front of the vehicle 100, assuming the vehicle 100 primarily moves along a forward driven direction 124. The first work unit 108 is toward the back of the vehicle 100. Other arrangements are possible, however. For some applications, such as mowing, it is preferable to have work units 109, 110 in front of the wheels 122 so that the wheels don’t flatten the turf before it can be cut. In such an arrangement, other wheels (not shown) may be placed behind the first work unit 108.

[0032] The second and third work units 109, 110 are shown aligned with each other in the path direction 106, although they may be offset from each other in other embodiments. There may be some cross track overlap between the work coverage of the first unit 108 and the second and third work units 109, 110. Such overlap may ensure thefull coverage width 112 gets worked when conditions (e.g., misalignment, steering of the mower) shifts the cross track alignment of one of the work units relative to the others. Those conditions could result in unworked strips of turf along the path direction 106 if the work units were aligned with no overlap. Nonetheless, excessive overlap may also be undesirable, as reduces full coverage width 112.

[0033] Note that additional work units may be incorporated with the vehicle 100, as indicated by blocks 111. These additional work units 111 may be located in different locations than shown in both in the cross path direction 107 and path direction 106. The additional work units 111 may have their own dedicated disengagement units (not shown) for separate and independent engagement and disengagement as described above. Other features and functionality described herein for a three-work unit vehicle 100 can be extended for embodiments with four, five, or more work units unless otherwise indicated. Some features described herein may also be applicable to ground care vehicles with one or two work units.

[0034] In the illustrated embodiment, the drive section 102 drive wheels 122 located between the first work unit 108 and one or both of the second and third work units 109, 110. The wheels 122 may be independently driven such that they can differentially steer the vehicle 100. The drive section 102 may include one or more electrical motors (not shown) that drive the wheels 122, or another source of mechanical power (e.g., an internal combustion engine) may be used.

[0035] As noted above, the vehicle 100 may further include a control unit that controls the disengagement units 118-120 in response to an electrical signal. In one embodiment, the control unit is configured to selectively engage and disengage the three disengagement units as each of the respective three work units crosses a geometric boundary of a zone in the work region. The selective lowering and lifting of the three lifting units can, among other things, minimize an unworked part of the zone proximate the geometric boundary. An example of this is shown in FIGS. 2-9.

[0036] In FIG. 2, a simplified diagram shows the work units 108-110 that are being used to work a zone 200. In this scenario, the zone 200 has a geometric boundary 202 that is arbitrarily shaped, such as seen for landscape boundaries such as putting greens. Lines204 represent a cutting line of the work units 108-110. The cutting lines may be generally considered a geometric feature of the work unit that will be fully within the zone 200 before work begins to prevent work (e.g., cutting) from extending across the boundary 202 outside the zone 200.

[0037] For some type of units such as reel mowers, the geometric features that define when the work unit is fully within the zone are the cutting line 204 that extend laterally across the work unit. Other geometric features may be defined for other types of work units. For example, a rotary mower would have a circular cutting shape at the trailing edge of the cutting circle traversed by the rotating blade. The trailing edge of the cutting circle is defined as the edge facing away from the forward direction 124 of vehicle motion. Other types of units could have geometric features that are unrelated to cutting, such as the pattern of a sprayer, and these could have arbitrary shapes, e.g., lines, curves, polylines, etc.

[0038] As seen in FIG. 2, the cutting line 204 of work unit 109 has just fully entered within the boundary 202. Therefore, as indicated by the shading, the work unit 109 has become engaged for work, e.g., being lowered and causing the cutting element to rotate. Work units 108 and 110 are still disengaged in FIG. 2. In FIGS. 3 and 4, work units 110 and 108 are engaged after their respective cutting lines 204 are completely within the boundary 202. Note in FIG. 4 that a portion of the work area 400 is shaded differently indicated that it has been worked (e.g., cut) by work unit 109, and this same convention is used in FIGS. 5-9.

[0039] Once fully inside the work zone 200, the work units 108-110 are selectively disengaged once any part of the cutting line 204 is outside of the boundary 202. This is shown in FIGS. 5-7 for cutting units 109, 110, and 108, respectively. In FIG. 8, the worked parts 802 have been completed in one pass of the vehicle 100. Multiple passes in the same direction but different locations can be repeated to cover the entire zone, sometimes followed by passes in a different direction, e.g., to form a pattern within the zone. For some passes, one or more work units may be disengaged through the entire path, e.g., where the work unit never fully enters the zone 200 during the pass.

[0040] The ground care vehicle 100 may include a speed sensor that detects a speed of the ground care vehicle in the path direction and provides a speed signal in response thereto. The selective engagement and disengagement of the three work units 108-110 can be timed based on the speed of the vehicle 100, location of the vehicle 100, and knowledge of the boundary 202. Other information may figure into the calculations, such as cross path and down path separation of the work units relative to one another and relative to a reference point of the vehicle 100, e.g., a location of the location sensor on the vehicle. Even in a semiautonomous mode (e.g., where the vehicle 100 is being driven / navigated by a human operator), the automatic selective engagement and disengagement of the three work units 108-110 can potentially provide a more accurate and consistent work pattern than the operator may be able to achieve through manual engagement and disengagement.

[0041] In FIG. 9, the zone has been worked repeatedly as shown in FIGS. 5-7. Regions 900 illustrate unworked parts of the zone 200 proximate the geometric boundary 202. The automatic engagement and disengagement of work units as described above can minimize a size of the unworked parts 900. The groundskeeper will typically want the entire zone 200 worked, e.g., when the work involves cutting, and so can follow up with one or more clean-up passes, as indicated by worked region 902.

[0042] Note that only one work unit (work unit 109 in this example) need be engaged to complete the clean-up pass. In other cases, e.g., two work units (e.g., 108, 109) may be used for a clean-up pass, with one or more unused units (e.g., 110) being kept outside the zone. By keeping the unused work units outside the zone 200, overlapping traversal within the zone 200 can be minimized while the ground care vehicle operates near the geometric boundary 202. In other words, the parts of the vehicle 100 not needed for work can be kept out of the zone 200, which can reduce stress on turf due to wheels that support the unused work units rolling over already worked parts of the zone 200.

[0043] In FIGS. 10 and 11, a perspective view and a top view show a ground care vehicle 1000 according to an example embodiment. The ground care vehicle 1000 includes a drive section 1002 that moves the ground care vehicle 1000. The drive section 1002 may include individual electric drive motors (not shown) rotatably coupled to wheels1022. A caster wheel 1023 is located behind the drive section 1002, the vehicle 1000 being steerable by differentially driving the wheels 1022.[00441 Three work units 1008-1010 are arrayed within the ground care vehicle 1000 in a pattern similar to that shown in FIG. 1. In this embodiment, the work units 1008-1010 are independently operable reel cutting units with integrated drive motors 1008a, 1009a, 1010a. Each work unit 1008-1010 has a mechanical and coupling interface to the central frame 1014 of the ground care vehicle 1000, which includes three disengagement units 1018, 1019, 1020 that selectably and individually lift and lower respective ones of the three work units 1008-1010. The engagement and disengagement may also involve powering and depowering, respectively, the motors 1008a-1010a.

[0045] The vehicle 1000 includes an electrical system 1016 powered by batteries located within battery housings 1017. In other embodiments, a different type of power could be used instead of or in addition to the batteries, e.g., an internal combustion engine (ICE) powering a generator, a fuel cell, solar cells, etc. The electrical system 1016 may include a manual controller 1029 as well as other circuitry that is not shown, including power conditioning circuitry, sensors, autonomous controllers, networking equipment, cooling systems, actuators, etc.

[0046] Seen on each of the work units 1008-1010 are respective debris collectors 1008b, 1009b, 1010b that collect debris, e.g., grass clippings, leaves, dirt. The debris collectors 1008b- 1010b are shown in a collecting configuration such that the debris move into the collector after being cut. As seen in FIG. 12, collector 1008b is shown in an emptying configuration, where the debris (not shown) can fall out of the collector 1008b onto the ground or into another collector, container, surface, or the like. Note that the collector 1008b may tip back further than shown in FIG. 12 in order to fully empty the debris.

[0047] As best seen in FIGS. 10 and 11, an actuator 1024 is operable to selectably transition the collectors 1008b-1010b between collecting and emptying configurations. The actuator 1024 is tied to three control cables 1025 that are attached to the collectors 1008b-1010b and causing the collectors to rotate about pivots (see pivot 1200 in FIG. 12). The weight of the collectors 1008b-1010b will allow them to return to the collectingconfiguration when the actuator 1024 is extended, therefore the control cables 1025 only operate in tension, so can be formed of relatively lightweight wire rope, for example. The actuator 1024 may be configured to execute a repeated sequence of short extensions and retractions in the emptying configuration so as to shake the collectors 1008b-1010b and more fully remove the debris.

[0048] The ground care vehicle 1000 may be partially autonomous or fully autonomous. In this context, partial autonomy may involve, in one embodiment, automatic engagement and disengagement of the work units 1008-1010 along pre-trained boundaries, while navigation is performed by an operator, e.g., as indicated by stand 1026 for carrying a human operator. A seat could be used instead of the stand 1026 in some embodiments. Emptying of the debris collectors 1008b-1010b may also be triggered autonomously with a human operator. In other embodiments, the vehicle 1000 may self-navigate while the user monitors and / or activates the work units 1008-1010 and / or debris collectors 1008b-1010b.

[0049] Fully autonomous operation may involve the vehicle 1000 self-navigating through the work region as well as automatic control of the work units 1008-1010. There still may be some human interaction before, during and after work, e.g., staging of the vehicle 1000, monitoring, remote pause, etc. In any of these configurations, the vehicle 1000 may include some sensors for navigation assist, such as proximity sensors, ground contact sensors, cameras, LIDAR, Global Position System (GPS) sensor, Global Navigation Satellite Systems sensors (GNSS), real-time kinetic (RTK) sensors, wheel encoders, etc. Further, the vehicle 1000 may store or otherwise have access to maps of the work region, including extent boundaries, obstacle boundaries, zone boundaries, elevations / slopes, etc. The vehicle 1000 can compare a current position (location and direction determined from sensors) with a map to guide vehicle 1000 along a desired path, as well as engaging and disengaging the work units 1008-1010 within work boundaries as they are crossed.

[0050] In some embodiments, the vehicle 1000 can navigate to a region to empty the debris collectors 1008b- 1010b in either a fully or partially autonomous mode, which is shown in the diagram of FIG. 13. Note that this figure and the associated description below may apply to a machine that collects any type of material, such as a sweeper, golfball collector, etc. As seen in FIG. 13, vehicle 100 from FIG. 1 is leaving the work zone 200 in the middle of work and heading to a predetermined emptying location 1300. Once at the location 1300, at least one actuator is activated (e.g., retracted) to transition at least one collector to the emptying configuration and empty the clippings or other debris. After emptying the clippings / debris, the at least one actuator is activated (e.g., extended) to transition the at least one collector to the collection configuration.

[0051] The emptying location 1300 may be a patch of ground where it is convenient to deposit debris, such as a compost pile or concrete pad. A single location 1300 may be predefined, or multiple predetermined locations 1300 may be predefined. In some embodiments, a general region may be defined, such as X feet from any boundary of a work zone. In other cases, any location along a region such as a paved trail can be used as an emptying location 1300 for debris. The debris may be conveniently picked up by a vehicle such as a vacuum or sweeper that moves along the trail.

[0052] In other embodiments, the emptying location may be a man-made structure such as an on-ground enclosure or trailer. In FIG. 14, a diagram illustrates a trailer 1400 according to an example embodiment. The vehicle 1000 shown in FIG. 10 is represented in this example, which drives onto a floor 1401 of the trailer 1400 and tilts the debris carriers 1008b-1010b. The floor 1401 has a feature such as a grating or sliding door through which the debris 1405 can pass.

[0053] A holding enclosure 1402 may be located below the floor to hold the debris 1405. The holding enclosure 1402 may be emptied later, e.g., by opening a trap door on the bottom of the holding enclosure 1402, and / or using a leaf blower or the like to force the debris through an opening on the bottom or side. The vehicle 1000 may lift the work units and drive up a ramp 1404 in order to access the trailer floor 1401. If the floor 1401 is instead located in a shed or other structure, a ramp may not be needed. In other embodiments, the trailer 1400 may be staged in a pit such that its floor 1401 is level to the ground. In such a case, the trailer 1400 may not need a holding enclosure, as the debris 1405 may be left in the pit after the trailer 1400 is later moved out.

[0054] In some embodiments, the trailer 1400 may be mobile such that it can be maneuvered (e.g., autonomously) proximate to the vehicle 1000 to minimize workinterruptions when emptying debris. This may involve including a steering element (e.g., steerable wheel 1406) and a drive element (e.g., driven wheel 1408). Autonomous movement may involve adding to the trailer 1400 self-navigation features (e.g., location sensors), capability to read / store maps, and other capabilities such as automatic raising and lowering of the ramp 1404. The trailer 1400 may be configured to coordinate its movements with the vehicle 1000, such that work interruptions can be minimized. For example, if the debris carriers 1008b-1010b are predicted to be full in ten minutes and the trailer 1400 will take an estimated five minutes to navigate to the current location of the mower, the trailer may start moving closer within five minutes so that it can be near to the vehicle 1000 before the debris carriers 1008b-1010b are full, minimizing the amount of time needed to empty the debris carriers 1008b-1010b and continue work.

[0055] The emptying operation can be managed by a controller on the vehicle 1000, and the emptying operation may be triggered automatically. In one embodiment, sensors may be used detect a fill level of debris in the debris carriers. Examples of various debris fill level sensors are shown and described in provisional patent application 63 / 528,457 filed July 24, 2023 (attorney docket numbers 0206.000321US60 / P01886- US01-PRO), which is hereby incorporated by reference in its entirety. The trigger for emptying could be when the collector is some fill level percentage that is less than completely full, which may allow time to planning the empty to minimize work interruption. For example, if the collector is 80% full but close to an emptying location, it may generally be preferable to empty the collector at 80% rather than wait until completely full, in which case it may take much longer to navigate to the emptying location. The trigger could initiate an autonomous emptying operation or alert an onboard or remote vehicle operator. In the latter case, the operator may initiate and possibly guide aspects of the debris emptying and return to work.

[0056] In FIG. 15, a perspective view shows details of a work unit 1009 with the debris carrier removed. Note that the geometry of the support structure associated with work unit 1009 may vary from other work units shown (e.g., work units 1008 and 1010 in FIG. 10), due to location on the vehicle 1000, configuration of the work unit 1009, and thelike. Those other work units may still have analogous components, but with different dimensions, orientations, and the like.[00571 A releasable clamp 1500 and support tube 1501 hold the debris carrier 1009b (not shown) in place and allow for easy removal and installation. A lifting arm 1502 is coupled to the support tube 1501 and includes an attachment 1504 to which disengagement unit 1019 (not shown) is attached. The lifting arm 1502 rotates about pivot 1503. The attachment 1504 includes a curved slot 1505, which allows the work unit 1009 to shift in location due to uneven terrain.

[0058] Support linkages 1506 couple the support tube 1501 to the lifting arm 1502 and also allow the work unit 1009 to shift (roll) due to uneven terrain. This is shown in greater detail in FIG. 16, which is a front view of the work unit 1009. As indicated by the intersection of dashed lines through the support linkages 1506, the support linkages are aligned to intersect at a roll center 1600 of the work unit 1009.

[0059] Also seen in FIGS. 15 and 16 are mounting tubes 1508, 1602 of the lifting arm 1502 and work unit 1009, respectively, that interface with each other to hold the work unit 1009 to the lifting arm 1502. A quick release pin 1510 facilitates quick manual release and attachment of the work unit 1009 from the vehicle 1000. In other embodiments, a similar tubular interface may be adapted to allow for autonomous change of work units, e.g., using a solenoid or other electromagnetic device to lock and unlock the work unit from the lifting arm or other carrying structure.

[0060] In FIGS. 17 and 18, top and side views show a work unit to vehicle interface 1700 that may be used in other embodiments. A tapered cap 1702 fits over a tapered post 1704. The tapers of the cap 1702 and post 1704 conform to each other help guide the parts together even if there is a vertical and horizontal misalignment between the two parts. Springs 1706, 1708 also help achieve alignment in horizontal and vertical directions. The cap 1702 and post 1704 can be used on the work vehicle and work unit, respectively, or vice versa.

[0061] The post 1704 has a locking slot 1712 into which a spring loaded latch 1710 fits to lock the post 1704 and cap 1702 together. The illustrated example is suitable for manual disengagement of the latch 1710, however the latch 1710 may be autonomouslydisengaged, e.g., via a solenoid, motor, or the like. In other embodiments, a manually operated latch 1710 as shown may be retained in an autonomous embodiment to facilitate easy manual unlocking. In such a case, the post 1704 may include a retractable latch as indicated by line 1715. The part of the post 1704 above the line can move out downward, disengaging the latch 1710 and allowing the post 1704 and cap 1702 to separate.

[0062] Assuming the work unit has its own electrical motor and / or other electrical components, the interface 1700 may also include an electrical connector that can be connected and disconnected at the same time as the cap 1702 and post 1704. In FIG. 18, a pair of connectors 1716, 1718 is shown that can provide an electrical interface, e.g., power and data. The connectors 1716, 1718 are aligned with the cap 1702 and post 1704 so that the electrical connections can be engaged and disengaged at the same time as the mechanical connections. The connectors 1716, 1718 may include similar features as the cap 1702 and post 1704, such as tapered surfaces and floating fasteners (e.g., springs). Some data, e.g., sensors, control signals, can be sent wirelessly between the work unit and vehicle, such that only a power connection may be needed.

[0063] The configuration shown in FIGS. 17 and 18 is one example of a work unit interface, and many variations are possible. For example, connectors could be directly integrated into the cap 1702 and post 1704, e.g., centrally located at the tip of the post 1704 and base of the cap 1702. The cap 1702 and post 1704 could have conical shapes instead of the illustrated tapered cuboids. The cap 1702 and post 1704 could have proximity sensors (e.g., optical emitter and receiver) that an autonomous vehicle can use to determine alignment and separation distance therebetween. Note that autonomous vehicles often include the functionality to autonomously approach and connect to an electrical charger, and so this functionality can be adapted to allow a vehicle to autonomously change work units via an interface as shown in FIGS. 17 and 18.

[0064] If a work unit includes other features such as debris collectors that are automatically empty-able, then there may be additional mechanical interfaces to allow for the swapping of work units while still retaining this functionality. In other embodiments, the work units may include onboard debris collector actuators, such that the electrical anddata connections as described above can suffice to provide collector emptying functionality.[00651 InFIGS. 19A-19C, a schematic diagram shows how a ground care vehicle 1900 may change out existing work units 1902 according to an example embodiment. This could be done autonomously, semi-autonomously, or manually. In this example, the vehicle has two work units 1902 and both are changed out at once, however the same concepts may apply to a single work unit swap, more than two work units, etc. In FIG. 19A, the vehicle 1900 navigates to a swap area 1901, which may be on the ground, rack, fixture, trailer, etc. The dashed-line rectangles indicate where the vehicle 1900 is targeting to leave the work units 1902. Another set of replacement work units 1904 is also in the swap area 1901.

[0066] In FIG. 19B, the vehicle 1900 has dropped off the work units 1902, and then backs away as indicated by the curved arrows. As indicated by the straight arrow on the left side of the figure, the vehicle aligns with the new work units 1904 and moves towards them until the work units 1904 are mounted to the vehicle. As seem in FIG. 19C, the vehicle 1900 backs away from the swap area 1901 with the new work units 1904 and can then perform work with the new work units 1904.

[0067] In some embodiments, the old and new work units 1902, 1904 may be the same, the swapping being initiated due to wear, operational temperatures, etc. The vehicle 1900 and / or work units 1902, 1904 may have sensors (e.g., microphones, vibration sensors, temperature sensors, optical sensors, electrical current sensors) to detect wear or other conditions that trigger a swap. In other embodiments, the old and new work units 1902, 1904 may be the same type (e.g., reel cutters) but different configurations (e.g., cutting height, cutting width). In other embodiments, the old and new work units 1902, 1904 may be different types (e.g., reel cutters, rotary cutters, etc.). In this way, the vehicle 1900 can act as a platform that can be flexibly reconfigured for different types of work, and may perform some or all aspects autonomously.

[0068] In FIGS. 20 and 21, perspective views show an example of how the ground care vehicle 1000 shown in FIG. 10 can be configured as a platform that uses different work units. In FIG. 10, the vehicle 1000 is shown with three reel cutter work units 1008-1010. In FIG. 20, the vehicle 1000 is shown with three rotary cutter work units 2008, 2009, 2010. In FIG. 21, a close-up view of work unit 2010 shows additional details, such as interface with lifting arm 1502. Because of the nature of rotary cutters, disengagement of the work units 2008-2010 may involve turning off motors 2008a, 2009a, 2010a and may not require lifting the work units 2008-2010. Thus, in these embodiments, the disengagement unit may be an electrical controller, although there still may be scenarios in which it is desired to lift the work units, e.g., to avoid an obstacle, to avoid excessive contact between rollers and turf.

[0069] The embodiments shown in FIGS. 10 and 20 may share common components, such as frame 1014, drive section 1002, electrical and control systems. Thus, the vehicle 1000 (or parts thereof) can serve as a common platform for different work implements and modes of operations. This may include the ability to run in autonomous mode for each of the different types of work units, and an autonomous controller may have custom behaviors particular to each work unit.

[0070] In the previous embodiments, disengagement units included actuators that directly lifted the work units off of the ground, where drive wheels and casters remained on the ground whether the work unit was lifted or not. In FIGS. 22-25, diagrams illustrate a disengagement unit of a ground care vehicle 2200 according to another example embodiment, in which caster wheels are lifted off the ground when the work unit is engaged. In FIG. 22, a perspective view shows a drive section 2202 that moves the ground care vehicle 2200 via a split roller 2203. The split roller 2203 has two separately driven and axially aligned roller sections that can be differentially driven, e.g., by two electrical motors. A work unit 2204 is attached to the vehicle 2200. The work unit 2204 in this example, is configured as a reel cutter as described elsewhere herein, and may include other types of work units also described elsewhere.

[0071] The ground care vehicle 2200 includes two caster wheel assemblies extending from the drive section 2202 in the path direction 2201. The two caster wheel assemblies 2206 each comprise a caster support arm 2206a. Each arm 2206a includes a proximal end 2206b fixably coupled to the drive section 2202 and a distal end 2206copposite the proximal end 2206b. The two caster wheel assemblies 2206 also each comprise a caster wheel 2206d at the distal end 2206c of the caster support arm 2206a.[00721 The work unit 2204 is offset from the drive section 2202 in the path direction 2201 such that a center of mass / gravity 2300 (see side view in FIG. 23) of the work unit 2204 is located between the drive section 2202 and the caster wheels 2206d. As best seen in FIG. 23, an actuator 2302 is coupled to a lift arm 2304 moves the work unit 2204 relative to the drive section 2202. Also seen in FIG. 23 is a battery 2320 that is located aft on the vehicle 2200.

[0073] The lifting arm 2304 is rotatably coupled to the drive section 2202 at a first end 2304a. The lifting arm 2304 is coupled to the work unit 2204 at a second end 2304b opposite the first end 2304a. Extension and retraction of the actuator 2302 causes rotation of the lifting arm 2304 around the first end 2304a, in particular around rotation axis 2308. Also note drive axis 2310, around which the rollers 2203 rotate. During lifting and lowering of the work unit 2204, the drive section 2202 and caster wheel assemblies 2206 rotate as a rigid body around the drive axis 2310.

[0074] In FIGS. 24 and 25, simplified diagrams show engagement and disengagement of the work unit 2204 via extension and retraction of the actuator 2302. As seen in FIG. 24, extension of the actuator 2302 (indicated by arrow 2400) raises the caster wheels 2206d (indicated by arrow 2402) and lowers the work unit 2204. A seen in FIG. 25, retraction of the actuator 2302 (indicated by arrow 2500) lowers the caster wheels 2206d and raises the work unit 2204 (indicated by arrow 2502). The shaded portions in FIGS. 24 and 25, which includes drive section 2202 and caster wheel assemblies 2206, rotate together as a rigid body. The work unit 2204 and lifting arm 2304 may be coupled by a rotating joint, in which case the work unit 2204 also rotates relative to the lifting arm 2304 between the orientations shown in FIGS. 24 and 25.

[0075] Generally, the extension of the actuator 2302 as shown in FIG. 24 lowers the work unit 2204 to the ground, resulting in a counter moment the raises the front end of the caster assemblies 2206. By balancing the weight along the path direction 2201 of the vehicle, this counter moment can be achieved largely by shifting weights of the vehicle components without causing excessive downward force on the work unit 2204. If the workunit 2204 has a debris collector as in this example, then the maximum downward force the work unit will apply to the ground should take into account the weight of collector when full of debris. The weight balance may also need to be adjusted for different work units that have different weights and / or different centers of mass. In some embodiments, the batteries 2320 can be slidably adjustable in the path direction in order to rebalance the vehicle. This rebalancing can be done manually or automatically.

[0076] In this example, two caster wheel assemblies 2306 are used with a single work unit 2204. The use of two caster wheel assemblies 2306 ensures the machine is balanced when the work unit 2204 is off the ground. Such an arrangement may be adapted for use in a vehicle with more than one work unit. In such a case, fewer than two caster assemblies per work unit may be used. For example, a vehicle may have two work units between two caster wheel assemblies. If one of the work units is lifted but the other is not, then the caster on the side of the lifted work unit will contact the ground while the caster on the side of the un-lifted, engaged work unit is lifted off the ground. This can be accomplished, for example, by splitting the drive unit frame down the middle along the path direction such that each frame section can rotate separately. The battery other counterweight can also be split between the two sections.

[0077] In FIG. 26, a block diagram shows electrical components of various apparatuses and systems as described herein. A work vehicle 2600 includes a system controller 2601 adapted to monitor and control various system functions. The system controller 2601 may include one or more processors that are coupled to one or more input / output (VO) busses 2602. The controller 2601 receives various inputs and executes one or more computer programs or applications stored in memory 2604. The memory 2604 may include volatile memory (e.g., dynamic random access memory) or non-volatile memory (e.g., flash memory). Other hardware is also coupled to the I / O busses 2602 including sensors 2603, power management circuits 2605, batteries 2606, drive controller circuits 2607, motor / actuators 2608, local data interface 2609, and network interface 2619.

[0078] The memory 2604 includes computer-readable instructions or applications that, when executed, e.g., by one or more processors, cause the controller 2601 to perform various calculations and / or issue commands. That is to say, the controller 2601 andmemory 2604 may together define a computing apparatus operable to process input data and generate the desired output to one or more components / devices. For example, the sensors 2603 may include a GPS receiver and / or wheel encoders that generate signals processed by the controller 2601 (e.g., via autonomous navigation software 2610) to generate speed and steering angle commands to the one or more motors 2608 to cause the drive wheels to rotate (at the same or different speeds and in the same or different directions). In other words, the controller 2601 may control the steering angle and speed of the vehicle 2600.

[0079] The sensors 2603 may include other suitable navigation sensors such as cameras, radar, LIDAR, RTK, contact sensors, proximity sensors, beacon detectors, boundary wire detectors, etc. Various schemes are known to map a work region, plan a work path through the work region, and autonomously navigate through the work region according to the plan. For example, U.S. Patent 11,334,082 (Autonomous Machine Navigation and Training Using Vision System); U.S. Patent 11,350,563 (Autonomous Grounds Maintenance Machines with Path Planning for Trap and Obstacle Avoidance) describe vision based navigation schemes and path planning and are hereby incorporated by reference.

[0080] In various embodiments described herein, the vehicle 2600 operates with one or more work units 2620 that perform a particular work task, such as cutting turf, aerating turf, spraying turf or other plants, ground leveling, irrigation, fertilization, etc. The work unit 2620 may also provide other ground care tasks unrelated to plants, such as snow throwing, snow plowing, salting, road / sidewalk cleaning, etc. The vehicle 2600 includes a mechanical and electrical interface (local interface 2609) that can interchangeably mount and control a variety of such work units. The work unit 2620 includes a local interface 2629 that is compatible with the local interface 2609 of the vehicle 2600 and may include both power and data interfaces. The data interfaces may utilize any combination of wired, wireless, and optical data transmission media.

[0081] The work unit 2620 may also include minimal or advanced electronics, the latter indicated by system controller 2621, I / O bus 2622, sensors 2623, motor s / actuators 2624 (which may include associated controllers that are not shown), and memory 2625.The memory 2625 may store work-unit-specific information useful to the vehicle, such as identity and configuration information 2626. This information about the work unit may include a serial number, model number, indication of type / function, current settings (e.g., cut height), accumulated run time, data related to optionally installed accessories (e.g., a debris collector), and the like. The memory 2625 may also store code for performing various function, such as a module 2627 that communicates status (e.g., self-test results, sensor readings) to the vehicle 2600 and a module 2628 that control accessories.

[0082] In addition to enabling and disabling the work unit 2620, the vehicle 2600 may also control other aspects of the work unit, such as speed, as indicated by work unit control module 2612 on vehicle. For example, if the work units are reel cutters, they reel speed may be independently controlled while mowing. This can compensate for different forward speed of the vehicle and or differential speed of the individual work units while making turns. In other cases, the speed can be varied to account for different turf conditions, e.g., heavier or lighter growth.

[0083] Other functional modules that relate to management of work units include work unit swapping module 2611 and debris management module 2613. The work unit swapping module 2611 may control various functions described in relation to FIGS. 19A- 19C, for example. The debris management module 2613 may manage debris collectors and control functions as shown in FIGS. 13-14, for example. A manual control module 2614 may allow an operator to manually program / walk, or ride on the vehicle 2600 (e.g., using with stand 1026 shown in FIG. 10 and controller 1029). The manual control module 2614 may facilitate non-work activities, such as loading onto trailer, wash unit, etc. The manual controls may include physical controls (e.g., buttons, levers, joysticks) that are attached to and / or fold of the rear of vehicle 2600 and may be generally grouped together with sensors 2603. In other embodiments, the manual controls may be wireless, and operate similar to operations center hardware as described below.

[0084] Note that navigation of the vehicle, whether autonomous or semi- autonomous, will generally be the purview of the vehicle’s navigation software 2610. However, the sensors used by this software 2610 may also be extended to include sensors 2623 of the work unit. For example, while these sensors 2623 may detect work-specificfunctions such as cutter speed, the location of at least some work units 2620 at the periphery of the vehicle 2600 may make them useful in guiding navigation. For example, when beginning to ascend a hill, a centrally located visual sensor (e.g., camera located on drive unit 1002 in FIG. 10) may be initially obscured by the hill, whereas a forward work unit (e.g., work units 1009, 1010) may have a better view, and may be configured to rotate maintain consistent ground contact (ground following). Thus, work unit mounted sensors 2623 may beneficially be used in vehicle navigation, as well as being useful in other operations such as debris emptying and work unit swapping.

[0085] In various embodiments described herein, the vehicle 2600 may operate with a trailer or other mobile or fixed platform 2630. In some configurations, the platform 2630 may not require electronics to facilitate autonomous operations, e.g., the vehicle 2600 may use visual navigation to find and move onto the platform 2630. In other embodiments, the platform 2630 may have a computing hardware (not shown) and other circuitry (e.g., sensors) that enable, for example, vehicle coordination functions 2631 and emptying / charging / cleaning functions 2632.

[0086] In some embodiments, the cleaning function may involve a jet of compressed water and / or air that is aimed at a work unit or other vehicle part when parked. This can be done at the same time as other activities, e.g., charging of vehicle batteries. This could alternatively be implemented using a fixed enclosure, e.g., a shed, docking station, etc.

[0087] Generally, the vehicle coordination functions 2631 relate to coordination of relative motion between the platform 2630 and the vehicle 2600 so that the vehicle 2600 can be properly located on the platform 2630 to perform the emptying / charging / cleaning functions 2632. Vehicle coordination functions 2631 may also involve the lowering of a ramp, setting of brakes, adjustment of height, etc. The platform 2630 and the vehicle 2600 may communicate via wireless networking or other wireless data communication setup, e.g., point-to-point radio transmissions.

[0088] The vehicle 2600 may have the ability to communicate with an operations center 2640 or computing device with similar functionality, e.g., an on-site mobile device. Example functions provided by the operations center include map management 2641,which involves the learning, definition, storage, and retrieval of maps of a work region. The maps may be generated and stored before work commences, e.g., after an initial training on work region boundaries and obstacles. In some cases, maps may be dynamically generated for one or more work sessions.

[0089] The operations center may assist in work planning 2642, such as identification of maps for use at a current location, estimating time to completion, monitoring work as it goes on, etc. The operations center may have facilities for fleet management 2643, which generally involve monitoring a fleet of vehicles for purposes such as coordination to match a collection of vehicles to a particular job, identification of spares, tracking equipment maintenance, etc.

[0090] 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.

[0091] 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.

[0092] The inter-device and intra-device communications may use any combination of wired and wireless communications. Examples of wireless data interfaces include WiFi, Bluetooth, cellular modem, inductive data interface, and NFC. Examples ofwired interfaces include Universal Serial Bus (USB), Ethernet, Controller Area Network (CAN), Inter-Integrated Circuit (I2C), and serial line (e.g., RS-232, IEEE 1394).[00931 InFIG. 27, a flowchart illustrates a method according to an example embodiment. The method involves moving 2700 a ground care vehicle within a work region along a path direction. A boundary is determined 2701 that the ground care vehicle passes across or along. While working at or across the boundary, one or more of three work units are selectively engaged and disengaged 2702 to facilitate working a path that conforms to the boundary. The selective engagement and disengagement causes the respective work unit to be engaged and disengaged from ground. This may be used, for example, to minimize an unworked part of the zone proximate the boundary and / or to minimize overlapping traversal by the ground care vehicle near the boundary.

[0094] In FIG. 28, a flowchart illustrates a method according to another example embodiment. The method involves, while working within a work region, determine 2800 a trigger signal for emptying a collector that collects debris from a work unit of a ground care vehicle. The ground care vehicle is navigated 2801 to a predetermined emptying location. An actuator or some other mechanism autonomously transitions 2802 the collector to a emptying configuration at the emptying location. After emptying the debris, the actuator transitions 2803 the collector to a collecting configuration such that additional debris can be collected during work.

[0095] In FIG. 29, a flowchart illustrates a method according to another example embodiment. The method involves, while working within a work region, determining 2900 a trigger signal for emptying a collector that collects debris from a work unit of a ground care vehicle. In response to the trigger signal, a signal is sent 2901 to a portable platform to cause the portable platform to autonomously maneuver proximate to the ground care vehicle. The ground care vehicle is navigated 2902 onto a surface of the portable platform and an actuator or some other mechanism autonomously causes the ground care vehicle to empty 2903 the debris onto (e.g., into a container on) the portable platform.

[0096] In FIG. 30, a flowchart illustrates a method according to another example embodiment. The method involves while working within a work region, determining 3000 a trigger signal for changing a first work unit of a ground care vehicle. The ground carevehicle is navigated 3001 to a predetermined swapping location, and the first work unit is unloaded 3002 at the swapping location. After unloading the first work unit, a second work unit is loaded 3003 from the swapping location onto the ground care vehicle and work is performed 3004 in the work region with the second work unit.

[0097] 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.

[0098] Example l is a ground care vehicle, comprising: a drive section that moves the ground care vehicle within a work region along a path direction; at least three work units that are arrayed in a pattern that defines a full coverage width of a path of the ground care vehicle, a cross path direction of the full coverage width being defined normal to the path; and associated with each of the three work units, three disengagement units that selectably and individually engage and disengage respective ones of the three work units, the disengagement causing the respective work unit to be disengaged from ground and the engagement causing the respective work unit to be engaged with the ground.

[0099] Example 2 includes the ground care vehicle of example 1, wherein the three work units comprise: a first work unit centrally disposed in the cross path direction; and second and third work units that are offset in the path direction from the first work unit, the first work unit located between the second and third work units in the cross path direction. Example 3 includes the ground care vehicle of example 2, wherein the drive section comprises drive wheels located between the first work unit and one or both of the second and third work units.

[0100] Example 4 includes the ground care vehicle of examples 1-4, wherein the at least three work units are any combination of: reel cutters, rotary cutters, rollers, brushes, spikers, verticutters, dethatchers, sprayers, and ball collectors. Example 5 includes the ground care vehicle of examples 1-5, further comprising a control unit that controls the disengagement units in response to an electrical signal.

[0101] Example 6 includes the ground care vehicle of example 5, wherein the control unit is configured to selectively engage and disengage the three disengagementunits as each of the respective three work units crosses a geometric boundary of a zone in the work region. Example 7 includes the ground care vehicle of example 6, wherein the selective engagement and disengagement of the three disengagement units minimizes an unworked part of the zone proximate the geometric boundary. Example 8 includes the ground care vehicle of example 6, further comprising: a speed sensor that detects a speed of the ground care vehicle in the path direction and provides a speed signal in response thereto; and a location sensor that detects a location of the ground care vehicle relative to the geometric boundary, wherein the selective engagement and disengagement of the three disengagement units is timed based on the speed signal and the location relative to the geometric boundary.

[0102] Example 9 includes the ground care vehicle of examples 1-8, wherein the one or more of the three work units are disengaged when the ground care vehicle follows a geometric boundary of a zone in the work region, the one or more disengaged work units being outside of the work zone and at least one of the three work units is engaged and located inside the zone. Example 10 includes the ground care vehicle of example 9, wherein the location of the disengaged units outside of the work zone minimizes overlapping traversal within the zone by the ground care vehicle near the geometric boundary.

[0103] Example 11 is ground care vehicle, comprising: a drive section that moves the ground care vehicle within a work region along a path direction; at least one collector that collects material from the work region; at least one actuator that selectably transitions the at least one collector between collecting and emptying configurations; and a controller operatively coupled to the drive section and the at least one actuator, the controller operable to cause the ground care vehicle to perform: while working within the work region, determine a trigger signal for emptying the at least one collector; navigate the ground care vehicle to a predetermined emptying location; and autonomously activate the at least one actuator to transition the at least one collector to the emptying configuration at the emptying location to empty the material.

[0104] Example 12 includes the ground care vehicle of example 11, wherein the controller is further operable to cause the ground care vehicle to after emptying thematerial, activate the at least one actuator to transition the at least one collector to the collecting configuration. Example 13 includes the ground care vehicle of example 11 or 12, further comprising at least one work unit that produces the material while working in the work region. Example 14 includes the ground care vehicle of example 13, wherein the material comprises at least one of debris, plant clippings, and golfballs.

[0105] Example 15 includes the ground care vehicle of examples 11-14, further comprising a location sensor providing a location measurement of at least one of a relative or absolute location of the ground care vehicle within the work region, wherein the controller autonomously performs the navigation to the predetermined emptying location. Example 16 includes the ground care vehicle of example 15, wherein the controller further causes the ground care vehicle to autonomously resume the work within the work region after emptying the material.

[0106] Example 17 includes the ground care vehicle of examples 11-16, wherein the emptying location comprises a portable platform with a holding enclosure for the emptied material. Example 18 includes the ground care vehicle of example 17, wherein the portable platform comprises an autonomous vehicle that can maneuver proximate to the ground care vehicle in the work region in response to the trigger signal. Example 19 includes the ground care vehicle of example 18, wherein in response to the trigger signal, send a signal to the portable platform to cause the portable platform to autonomously maneuver proximate to the ground care vehicle. Example 20 includes the ground care vehicle of example 19, wherein the trigger signal is based on at least one of: an estimated fill level of the material in the collector; and an estimated to time for the ground care vehicle and the portable platform to meet.

[0107] Example 21 includes the ground care vehicle of example 17, wherein the ground care vehicle navigates onto a surface of the portable platform before emptying the material. Example 22 includes the ground care vehicle of example 21, wherein the portable platform is configured to carry the ground care vehicle to and from the work region. Example 23 includes the ground care vehicle of example 17, wherein the portable platform comprises a charging station operable to charge a battery of the ground care vehicle.Example 24 includes the ground care vehicle of example 17, wherein the portable platform comprises a cleaning station that cleans a work unit of the ground care vehicle.[01081 Example 25 includes the ground care vehicle of examples 11-24, further comprising a material sensor coupled to the controller, the material sensor measuring a fill level of the material within the at least one collector, wherein the trigger signal is based on the fill level exceeding a threshold. Example 26 includes the ground care vehicle of any one of examples 11-25, wherein the trigger signal is based on at least one of: an elapsed time of work; a distance between the work vehicle and the emptying location; and an estimated time to complete a pass in the work region.

[0109] Example 27 is a ground care vehicle, comprising: a drive section that moves the ground care vehicle within a work region along a path direction; a first work unit that performs work in the work region, the first work unit attached to a mounting point of the ground care vehicle; and a controller operatively coupled to the drive section and the first work unit, the controller operable to perform: while working within the work region, determine a trigger signal for changing the first work unit; navigate the ground care vehicle to a predetermined swapping location; unload the first work unit at the swapping location; and after unloading the first work unit, loading a second work unit from the swapping location onto the mounting point of the ground care vehicle and performing work in the work region with the second work unit.

[0110] Example 28 includes the ground care vehicle of example 27, further comprising a location sensor providing a location measurement of at least one of a relative or absolute location of the ground care vehicle relative to the swapping location, wherein the controller autonomously performs the unloading of the first work unit and the loading of the second work unit. Example 29 includes the ground care vehicle of example 27 or 28, wherein the first and second work units comprise first and second cutting units. Example 30 includes the ground care vehicle of example 29, wherein the first and second cutting units are configured with different cut heights. Example 31 includes the ground care vehicle of example 29, wherein the first and second cutting units are configured with a same cut height, wherein the first cutting unit is unloaded and the second cutting unit is loaded when the first cutting unit is worn, damaged, or exceeds a work threshold.

[0111] Example 32 includes the ground care vehicle of examples 27-31 , wherein the first and second work units comprise respective first and second electric motors, an interface between the ground care vehicle comprising an electrical interface that is disconnected from the first work unit when the first work unit is unloaded and connected to the second work unit when the second work unit is loaded. Example 33 includes the ground care vehicle of examples 27, 28, and 32, wherein the first and second work units comprise different types of units selected from a group comprising: a reel cutting unit, a rotary cutting unit, a roller unit, an aerating unit, a spraying unit, a dethatching unit, and a ball collector.

[0112] Example 34 is ground care vehicle, comprising a drive section that moves the ground care vehicle within a work region along a path direction; two caster wheel assemblies extending from the drive section in the path direction, the two caster wheel assemblies each comprising: a caster support arm comprising: a proximal end fixably coupled to the drive section; and a distal end opposite the proximal end; and a caster wheel at the distal end of the caster support arm; a work unit offset from the drive section in the path direction, a center of mass of the work unit being located between the drive section and the caster wheels; and an actuator that moves the work unit relative to the drive section, retraction of the actuator lowering the caster wheels and raising the work unit and extension of the actuator raising the caster wheels and lowering the work unit.

[0113] Example 35 includes the ground care vehicle of example 34, wherein the lowering and raising of the caster wheels rotates the drive section around a drive axis. Example 36 includes the ground care vehicle of example 34 or 35, wherein the drive section comprises a differentially driven split roller. Example 37 includes the ground care vehicle of example 34-36, further comprising a lifting arm rotatably coupled to the drive section at a first end and coupled to the work unit at a second end opposite the first end, the extension and retraction of the actuator causing rotation of the lifting arm around the first end.

[0114] 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 theaccompanying 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.

[0115] 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.

[0116] Unless otherwise indicated, all numbers expressing feature sizes, amounts, and physical properties used in the specification and claims 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 and attached claims 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.

[0117] 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.

[0118] 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.

[0119] 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 disclosed embodiments 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 ground care vehicle, comprising: a drive section that moves the ground care vehicle within a work region along a path direction; at least three work units that are arrayed in a pattern that defines a full coverage width of a path of the ground care vehicle, a cross path direction of the full coverage width being defined normal to the path; and associated with each of the three work units, three disengagement units that selectably and individually engage and disengage respective ones of the three work units, the disengagement causing the respective work unit to be disengaged from ground and the engagement causing the respective work unit to be engaged with the ground.

2. The ground care vehicle of claim 1, wherein the three work units comprise: a first work unit centrally disposed in the cross path direction; and second and third work units that are offset in the path direction from the first work unit, the first work unit located between the second and third work units in the cross path direction.

3. The ground care vehicle of claim 2, wherein the drive section comprises drive wheels located between the first work unit and one or both of the second and third work units.

4. The ground care vehicle of any one of claims 1-3, wherein the at least three work units are any combination of: reel cutters, rotary cutters, rollers, brushes, spikers, verticutters, dethatchers, and sprayers.

5. The ground care vehicle of any one of claims 1-4, further comprising a control unit that controls the disengagement units in response to an electrical signal.

6. The ground care vehicle of claim 5, wherein the control unit is configured to selectively engage and disengage the three disengagement units as each of the respective three work units crosses a geometric boundary of a zone in the work region.

7. The ground care vehicle of claim 6, wherein the selective engagement and disengagement of the three disengagement units minimizes an unworked part of the zone proximate the geometric boundary.

8. The ground care vehicle of claim 6 or 7, further comprising: a speed sensor that detects a speed of the ground care vehicle in the path direction and provides a speed signal in response thereto; and a location sensor that detects a location of the ground care vehicle relative to the geometric boundary, wherein the selective engagement and disengagement of the three disengagement units is timed based on the speed signal and the location relative to the geometric boundary.

9. The ground care vehicle of any one of claim 1-8, wherein the one or more of the three work units are disengaged when the ground care vehicle follows a geometric boundary of a zone in the work region, the one or more disengaged work units being outside of the work zone and at least one of the three work units is engaged and located inside the zone.

10. The ground care vehicle of claim 9, wherein the location of the disengaged units outside of the work zone minimizes overlapping traversal within the zone by the ground care vehicle near the geometric boundary.

11. A method of operating a ground care vehicle with at least three work units that are arrayed in a pattern that defines a full coverage width of a path of the ground care vehicle, a cross path direction of the full coverage width being defined normal to the path, the method comprising:moving the ground care vehicle within a work region along a path direction; determining a boundary that the ground care vehicle passes across or along; and while working at or across the boundary, selectively engaging and disengaging one or more of the at least three work units to facilitate working a path that conforms to the boundary, the selective engagement and disengagement causing the respective work unit to be engaged and disengaged from ground.

12. The method of claim 11, wherein the three work units comprise: a first work unit centrally disposed in the cross path direction; and second and third work units that are offset in the path direction from the first work unit, the first work unit located between the second and third work units in the cross path direction.

13. The method of claim 12, wherein the drive section comprises drive wheels located between the first work unit and one or both of the second and third work units.

14. The method of any one of claims 11-13, wherein the at least three work units are any combination of: reel cutters, rotary cutters, rollers, brushes, spikers, verti cutters, dethatchers, and sprayers.

15. The method of any one of claims 11-14, wherein the selective engaging and disengaging of the one or more work units is performed by disengagement units that selectably and individually engage and disengage respective ones of the three work units, the method further comprising sending an electrical signal to control the disengagement units.

16. The method of claim 15, further comprising: detecting when each of the respective three work units crosses a geometric boundary of a zone in the work region; andvia the control unit, selectively engaging and disengaging the three disengagement units as each of the respective three work units crosses the geometric boundary.

17. The method of claim 16, wherein the selective engagement and disengagement of the three disengagement units minimizes an unworked part of the zone proximate the geometric boundary.

18. The method of claim 15 or 16, further comprising: detecting a speed of the ground care vehicle in the path direction via a speed sensor; and detecting a location of the ground care vehicle relative to the geometric boundary via a location sensor, wherein the selective engagement and disengagement of the three disengagement units is timed based on the speed signal and the location relative to the geometric boundary.

19. The method of any one of claims 11-18, further comprising disengaging the one or more of the three work units when the ground care vehicle follows a geometric boundary of a zone in the work region, the one or more disengaged work units being outside of the work zone and at least one of the three work units being engaged and located inside the zone.

20. The method of claim 19, wherein the location of the disengaged units outside of the work zone minimizes overlapping traversal within the zone by the ground care vehicle near the geometric boundary.

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