Work vehicle magnetorheological fluid joystick system providing implement command guidance

Abstract

The present disclosure relates to work vehicle magnetorheological fluid joystick systems that provide implement command guidance. Specifically, a work vehicle magnetorheological fluid (MRF) joystick system includes a joystick device, a MRF joystick resistance mechanism, a controller architecture, and an implement tracking data source configured to track movement of an implement during operation of the work vehicle. The joystick device, in turn, includes a base housing, a joystick, and a joystick position sensor. The MRF joystick resistance mechanism is controllable to vary a MRF resistance that resists movement of the joystick relative to the base housing. The controller architecture is configured to: (i) track movement of the implement relative to a virtual boundary with data provided by the implement tracking data source; and (ii) command the MRF joystick resistance mechanism to vary the MRF resistance based at least in part on the implement movement relative to the virtual boundary.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority to U.S. Provisional Application No. 63 / 019,083, filed with the U.S. Patent and Trademark Office on May 1, 2020. Technical Field

[0003] This disclosure relates to a work vehicle magnetorheological fluid (MRF) joystick system that guides the joystick-controlled positioning of a work vehicle implement by resisting changes in the force applied by the MRF to the joystick movement. Background Technology

[0004] Joystick devices are commonly used to control various operational aspects of work vehicles employed in construction, agriculture, forestry, and mining. For example, in the case of work vehicles equipped with a boom assembly, the operator can use one or more joystick devices to control the movement of the boom assembly, and thus control the movement of tools or implements mounted to the external end of the boom assembly. Common examples of work vehicles with such joystick-controlled boom assemblies include: excavators, feller bunchers, skidders, tractors (on which modular front-end loaders and backhoe attachments can be mounted), tractor loaders, wheel loaders, and various compact loaders. Similarly, in the case of bulldozers, motor graders, and other work vehicles equipped with earth-moving blades, the operator can control the movement and positioning of the blade via an interface connected to one or more joysticks. As in the cases of motorized graders, bulldozers, and certain loaders such as skid steer loaders, joysticks are typically used to operate or otherwise control the directional movement of the work vehicle chassis itself. Given the prevalence of joysticks in work vehicles, and considering the relatively challenging dynamic environments in which they often operate, there is a continuous need to improve the design and functionality of work vehicle joystick systems, particularly to the extent that such advancements enhance the safety and efficiency of work vehicle operation. Summary of the Invention

[0005] A magnetorheological fluid (MRF) joystick system for use on a work vehicle is disclosed. In one embodiment, the work vehicle MRF joystick system includes: a joystick device, a tool tracking data source, an MRF joystick resistance mechanism, and a controller architecture. The joystick device further includes: a base housing; a joystick mounted to and movable relative to the base housing; and a joystick position sensor configured to monitor joystick movement relative to the base housing. The tool tracking data source is configured to track tool movement during operation of the work vehicle, while the MRF joystick resistance mechanism can be controlled to change the MRF resistance impeding the joystick movement relative to the base housing. The controller architecture is coupled to the MRF joystick resistance mechanism, the joystick position sensor, and the tool tracking data source. The controller architecture is configured to: (i) track tool movement relative to a virtual boundary using data provided by the tool tracking data source; and (ii) command the MRF joystick resistance mechanism to change the MRF resistance based at least in part on the tool movement relative to the virtual boundary.

[0006] In other embodiments, the work vehicle MRF joystick system includes: a joystick assembly, an MRF joystick resistance mechanism, and a controller architecture. The joystick assembly has: a base housing; a joystick mounted to and movable relative to the base housing; and a joystick position sensor configured to monitor joystick movement relative to the base housing. The MRF joystick resistance mechanism is at least partially integrated into the base housing and can be controlled to selectively resist joystick movement relative to the base housing. The controller architecture, coupled to the MRF joystick resistance mechanism and the joystick position sensor, is configured to: (i) when operator movement of the joystick in the operator input direction is detected, determine whether continuous joystick movement in the operator input direction would cause the machine to be on the verge of violating a first virtual boundary; and (ii) when it is determined that continuous joystick movement in the operator input direction would cause the machine to be on the verge of violating the first virtual boundary, command the MRF joystick resistance mechanism to generate a first MRF resistance that impedes continuous joystick movement in the operator input direction.

[0007] In further implementation, the MRF joystick system includes a joystick device comprising: a joystick rotatable relative to a base housing; an MRF joystick resistance mechanism controllable to selectively resist rotation of the joystick about at least one axis relative to the base housing; and an implement tracking data source configured to track implement movement during operation of the work vehicle. A controller architecture is coupled to the joystick device, the MRF joystick resistance mechanism, and the implement tracking data source. The controller architecture is configured to: (i) track implement movement relative to at least a first virtual boundary when the operator commands the implement to move using the joystick device; and (ii) command the MRF joystick resistance mechanism to change the MRF resistance that impedes movement of the joystick along at least one degree of freedom to provide tactile feedback to the operator indicating the implement's approach to the first virtual boundary.

[0008] Details of one or more embodiments are set forth in the accompanying drawings and the description below. Other features and advantages will become apparent from this description, the drawings, and the claims. Attached Figure Description

[0009] At least one example of this disclosure will be described below in conjunction with the following figures:

[0010] Figure 1 This is a schematic diagram of an example magnetorheological fluid (MRF) joystick system on a work vehicle (here, an excavator) as illustrated in an example embodiment of the present disclosure;

[0011] Figure 2 From Figure 1 The perspective view from inside the excavator cab shown illustrates two joystick devices that can be included in the example MRF joystick system and used by the operator to control the movement of the excavator boom assembly.

[0012] Figure 3 and Figure 4 This is a schematic cross-sectional view of an example MRF joystick system, partially shown and taken along a vertical section through the joystick, illustrating one possible configuration of the MRF joystick system;

[0013] Figure 5 This is a flowchart of an example process performed appropriately by the controller architecture of an MRF joystick system, which modulates the MRF resistance that selectively inhibits joystick movement based on the movement of the implement relative to one or more virtual boundaries;

[0014] Figure 6 It is one of the ones that can be Figure 1The diagram illustrates one method of using an excavator for mining features, while the controller architecture of the MRF joystick system is implemented in the example use case. Figure 5 The processing described in the text; and

[0015] Figure 7 The diagram shows additional example work vehicles illustrating, in a non-exhaustive manner, implementations in which the MRF joystick system can be advantageously integrated.

[0016] The same reference numerals in the various figures indicate the same elements. For simplicity and clarity, descriptions and details of well-known features and techniques may be omitted to avoid unnecessarily obscuring the exemplary and non-limiting embodiments of the invention described in the following detailed description. It should also be understood that, unless otherwise stated, features or elements appearing in the figures are not necessarily drawn to scale. Detailed Implementation

[0017] Embodiments of the present disclosure are illustrated in the accompanying drawings, which are briefly described above. Various modifications to the exemplary embodiments will be conceived by those skilled in the art without departing from the scope of the invention as set forth in the appended claims. As appears herein, the term "work vehicle" includes all parts of the work vehicle. Thus, in an implementation where a boom assembly terminated in an implement is attached to the chassis of the work vehicle, the term "work vehicle" encompasses both the chassis and the boom assembly, as well as the implement mounted to the end of the boom assembly.

[0018] Overview

[0019] The following discloses a magnetorheological fluid (MRF) joystick system for work vehicles that provides implement command guidance through controlled variations of resistance applied via an MRF, which impedes joystick movement along one or more degrees of freedom (DOF). Implementations of the MRF joystick system include a processing subsystem or “controller architecture” operationally coupled to an MRF joystick resistance mechanism; that is, a mechanism, device, or damper comprising a magnetorheological fluid and capable of modifying the fluid’s rheology (viscosity) by variations in the intensity of an electromagnetic field to provide controlled adjustment of the resistance impeding joystick movement along at least one DOF. This resistance is hereinafter referred to as “MRF resistance,” and the degree to which the MRF resistance impedes joystick movement along a particular direction or combination of directions is referred to as “joystick stiffness” in the relevant direction.

[0020] During operation of an MRF joystick system, the controller architecture provides desired machine command guidance by suppressing changes in MRF resistance to joystick movement. Specifically, in an implementation of an MRF joystick system, the controller architecture can command the MRF joystick resistance mechanism to change the MRF resistance based on joystick-controlled machine movement relative to one or more virtual boundaries. When joystick movement occurs in a specific direction (referred to herein as the "operator input direction"), the controller architecture determines whether continued joystick movement along the operator input direction will cause the machine to reach a predetermined proximity to one or more virtual boundaries, which are established by the controller in a three-dimensional (3D) spatial volume. If it is determined that continued joystick movement along the operator input direction will cause the machine to reach the predetermined proximity to the virtual boundaries, the controller architecture commands the MRF joystick resistance mechanism to generate MRF resistance that delays continued joystick movement along the operator input direction. In doing so, the MRF joystick system uses the relevant joystick and provides tactile cues to the operator to slow (if not halt) the joystick's movement in the direction of operator input.

[0021] If the operator continues to turn (or otherwise move) the joystick in the operator input direction, the controller architecture can repeat the above process to progressively increase joystick resistance. For example, in one method, the controller architecture commands the MRF joystick resistance mechanism to increase the MRF resistance against joystick movement in the operator input direction as the joystick-controlled implement approaches an adjacent virtual boundary, wherein the MRF resistance increases substantially proportionally to the decrease in distance or gap between the implement and the virtual boundary. Alternatively, the controller architecture can determine when the joystick-controlled implement is on the verge of violating the virtual boundary; for example, predicting it to occur within a relatively short time frame (e.g., about one second or less). When it is determined that the implement is on the verge of violating the virtual boundary, the controller architecture can command the MRF joystick resistance mechanism to generate maximum MRF resistance that impedes further joystick movement in the operator input direction. In an implementation, the maximum MRF resistance is sufficient to completely arrest joystick movement in the operator input direction, or at least make such joystick movement relatively difficult, to further discourage (if not prevented) the implement from violating the virtual boundary. In other cases, when the machine violates this virtual boundary, the controller architecture can generate tactile cues, such as brief resistance pulses or sensory detents.

[0022] In various operational scenarios, the aforementioned MRF-based joystick guidance scheme and corresponding virtual boundaries have been usefully established. For example, this virtual boundary can be advantageously utilized in conjunction with the operation of bulldozers, motorized graders, excavators, backhoes, or similar work vehicles equipped with (e.g., integrated) slope control systems. The MRF joystick system provides MRF-generated tactile feedback to help the operator position the implement in a way that imparts the desired slope or topology to the ground surface. Specifically, in this implementation, elevation coordinates defined by design data loaded into the work vehicle's onboard computer can be used to establish this virtual boundary, and varying MRF drag effects are generated based on the proximity of the implement (e.g., the cutting edge) to this virtual boundary. Similarly, in other excavation operations, virtual boundaries can be established corresponding to the surface of trenches or other excavation features created as desired using the work vehicle's excavation tools or implements. For example, in at least some implementations, a virtual boundary can be established in the form of a two-dimensional (2D) or 3D excavation floor, which may represent a lower threshold to prevent further excavation below the excavation floor, as desired. In other cases, the controller of the MRF joystick system can establish a virtual boundary around or adjacent to obstacles (e.g., buried conduits or electrical pipes) to prevent or at least inhibit operator joystick commands that might otherwise cause the implement to unnecessarily approach or come into contact with such obstacles during excavation work. Similarly, virtual boundaries can be used to help guide the movement of joystick-controlled implements during non-excavation work. For example, in this latter case, a virtual boundary in the form of a virtual ceiling can be established to limit the height above ground to which the bucket or other implements can be raised; this may be useful, for example, when work vehicles (such as tractors equipped with front-end loader (FEL) attachments) are operating in enclosed structures (e.g., barns), mines, or work areas with elevated obstacles.

[0023] As described above, during joystick-controlled movement of the implement, the implementation of the MRF joystick system provides intuitive tactile guidance to enhance the operator's awareness of the implement's movement relative to one or more virtual boundaries. This, in turn, assists or guides the operator in commanding the implement's movement with a higher degree of precision, increased efficiency, and a reduced likelihood of accidental or problematic implement movement. Furthermore, the use of MRF technology to guide joystick input movement offers several advantages compared to the use of other mechanisms that can potentially selectively restrict joystick movement (e.g., brake mechanisms and artificial force feedback (AFF) motors). As one such advantage, the rheological properties (e.g., viscosity) of a given magnetorheological fluid can typically be adjusted in a relatively precise, obvious, and rapid manner by varying the intensity of the EM field immersed in the magnetorheological fluid. Since the intensity of the EM field can also be changed in a controlled and responsive manner, the MRF joystick resistance mechanism can provide a highly simplified, low-hysteresis response time, for example, approximately a few milliseconds (ms) or less. Furthermore, the MRF joystick resistance mechanism can precisely vary the intensity of MRF resistance within a substantially continuous range. These characteristics enable the MRF joystick device to generate a variety of different tactile resistance effects that can be perceived by the operator of the work vehicle, including selectively applying a stop and continuously varying the MRF resistance to suppress joystick movement in a specific direction. As a further benefit, the MRF joystick system can provide reliable, low-noise operation when combined with the use of non-toxic magnetorheological fluids (e.g., those containing carbonyl iron).

[0024] Now, will be combined Figures 1 to 6 This section describes an example implementation of an MRF joystick system for work vehicles. In the examples described below, the MRF joystick system is primarily discussed within the context of a specific type of work vehicle (i.e., an excavator). Furthermore, in the examples below, the MRF joystick system includes two joystick devices having joysticks capable of rotating about two vertical axes, used to control the movement of the excavator's boom assembly and the implements (e.g., bucket) attached to the boom assembly. Although the examples are given below, in further implementations, the MRF joystick system may include more or fewer joysticks, and each joystick device may be able to move with any number of DOFs and along any suitable motion pattern; for example, in an alternative embodiment, a given joystick may be able to rotate about a single axis, or may also be restricted to moving along a predetermined trajectory (e.g., an H-shaped trajectory) or motion pattern. Moreover, the MRF joystick system described below can be deployed on a wide range of work vehicles including joystick-controlled functions, as discussed below. Figure 7 Additional examples of work vehicles are discussed.

[0025] Example MRF joystick system providing machine command guidance

[0026] Initial reference Figure 1 An example work vehicle (excavator 20 in this case) equipped with a work vehicle MRF joystick system 22 is presented. In addition to the MRF joystick system 22, the excavator 20 includes a boom assembly 24 terminated in a tool or implement (such as bucket 26). Various other implements can be interchanged with bucket 26 and attached to the end of the boom assembly 24, including other buckets, grapples, and hammers. The excavator 20 has a body or chassis 28, a tracked underframe 30 supporting the chassis 28, and a cab 32 located at the front of the chassis 28 and surrounding the operator's cab. The excavator boom assembly 24 extends from the chassis 28 and includes an inner or proximal boom 34 (hereinafter referred to as "lifting boom 34"), an outer or distal boom 36 (hereinafter referred to as "dipper stick 36"), and multiple hydraulic cylinders 38, 40, and 42 as major structural components. Hydraulic cylinders 38, 40, and 42 further include: two lifting cylinders 38, a bucket handle cylinder 40, and a bucket cylinder 42. The extension and retraction of the lifting cylinders 38 rotate the boom 34 about a first pivot joint, at which the boom 34 engages with the excavator chassis 28 (here, adjacent to the right side of the cab 32). The extension and retraction of the bucket handle cylinder 40 rotate the bucket handle 36 about a second pivot joint, at which the bucket handle 36 engages with the boom 34. Finally, the extension and retraction of the bucket cylinder 42 rotates or "curls" the excavator bucket 26 about a third pivot joint, at which the bucket 26 engages with the bucket handle 36.

[0027] Hydraulic cylinders 38, 40, and 42 are included in an electrohydraulic (EH) actuation system 44, which... Figure 1The section is enclosed by a box 46 entitled "Actuator with Function Controlled by Joystick". The movement of the excavator's external components 24 is controlled using at least one joystick located within the excavator cab 32 and included in the MRF joystick system 22. Specifically, the operator can use one or more joysticks included in the MRF joystick system 22 to control the extension and retraction of hydraulic cylinders 38, 40, 42, and to control the slewing of the boom assembly 24 via the rotation of the excavator chassis 28 relative to the tracked undercarriage 30. The depicted EH actuation system 44 also includes various other unillustrated hydraulic components, which may include flow lines (e.g., flexible hoses), check valves or safety valves, pumps, fittings, filters, etc. Additionally, the EH actuation system 44 includes an electronic valve actuator and a flow control valve (such as a spool valve) that can be modulated to adjust the flow rate of pressurized hydraulic fluid into and out of hydraulic cylinders 38, 40, 42. If the controller architecture 50 described below can control the movement of the boom assembly 24 via commands sent to a selected actuator in the actuator 46 (which performs the joystick control function of the excavator 20), then the specific construction or architecture of the EH actuation system 44 stated herein is largely irrelevant to the implementation of this disclosure.

[0028] As in Figure 1 Schematably illustrated in the upper left portion, the work vehicle MRF joystick system 22 includes one or more MRF joystick devices 52, 54. As appears herein, the term "MRF joystick device" refers to an operator input device comprising at least one joystick or control lever, the movement of which can be selectively resisted by utilizing an MRF joystick resistance mechanism of the type described herein. Although for clarity, in Figure 1 One such MRF joystick device 52 is schematically shown, but the MRF joystick system 22 may include any actual number of joystick devices, as indicated by symbol 58. In the case of the example excavator 20, the MRF joystick system 22 will typically include two joystick devices; for example, in conjunction with the following... Figure 2 The control lever devices 52 and 54 are described. The following further discusses how two such control lever devices 52 and 54 can be used to control the movement of the excavator boom assembly 24. However, firstly, a method for... Figure 1 The general discussion of the joystick device 52, which is schematically illustrated, is intended to establish a general framework for a better understanding of the embodiments of this disclosure.

[0029] like Figure 1The MRF joystick device 52 is schematically illustrated as including a joystick 60 mounted to a lower support structure or base housing 62. The joystick 60 is movable relative to the base housing 62 along at least one DOF and rotatable relative to the base housing 62 about one or more axes. In the depicted embodiment, and as indicated by arrow 64, the joystick 60 of the MRF joystick device 52 is rotatable relative to the base housing 62 about two vertical axes, as will also be described below. The MRF joystick device 52 includes one or more joystick position sensors 66 for monitoring the current position and movement of the joystick 60 relative to the base housing 62. The MRF joystick device 52 may also include various other components 68, including buttons, dials, switches, or other manual input features, which may be located on the joystick 60 itself, on the base housing 62, or a combination of both. Spring components (gas springs or mechanical springs), magnets, or fluid dampers can be incorporated into the joystick assembly 52 to provide a desired return rate to the joystick's home position and to fine-tune the desired feel or "stiffness" of the joystick 60 perceived by the operator when interacting with the MRF joystick assembly 52. ​​In more complex configurations, various other components (e.g., potentially including one or more AFF motors) may also be incorporated into the MRF joystick assembly 52. ​​In other implementations, such components may be omitted from the MRF joystick assembly 52.

[0030] The MRF joystick resistance mechanism 56 is at least partially integrated into the base housing 62 of the MRF joystick device 52. The MRF joystick resistance mechanism 56 (and other MRF joystick resistance mechanisms mentioned herein) may also be alternatively referred to as an "MRF damper," an "MRF brake device," or simply an "MRF device." The MRF joystick resistance mechanism 56 can be controlled to adjust the MRF resistance, and thus the joystick stiffness, to resist joystick movement relative to the base housing 62 along at least one DOF. During operation of the MRF joystick system 22, the controller architecture 50 can selectively command the MRF joystick resistance mechanism 56 to increase the joystick stiffness, thereby impeding joystick rotation about a specific axis or combination of axes. As discussed more fully below, the controller architecture 50 can command the MRF joystick resistance mechanism 56 to apply such MRF resistance by increasing the intensity of the EM field of the magnetorheological fluid contained in the mechanism 56, which is at least partially immersed in it. Figure 3 and Figure 4This describes a generalized example of a manner in which the MRF joystick resistance mechanism 56 can be implemented. When it is determined that continuous rotation of the joystick 60 in a particular direction (referred to herein as the "operator input direction") would cause the implement to move to a defined proximity to a virtual boundary or violate the virtual boundary, the controller architecture 50 may command the MRF motion resistance mechanism 56 to generate such MRF resistance. In the case of the excavator 20, specifically, the controller architecture 50 determines that continuous rotation of the joystick 60 included in the MRF joystick device 52 (and / or continuous rotation of another joystick included in a second similar MRF joystick device) would cause the bucket 26 (or another portion of the boom assembly 24) to move to a defined proximity to the virtual boundary and / or cause the bucket 26 to move across the virtual boundary.

[0031] In terms of the projection manner in which rotation of the joystick 60 (and / or the second joystick included in the MRF joystick system 22) results in movement of the excavator boom assembly 24 relative to one or more virtual boundaries in discussion, the controller architecture 50 considers inputs from multiple data sources, including multiple non-joystick sensors 70 on the excavator 20. These non-joystick sensors 70 may include sensors included in an implement tracking data source 72, which may include any sensor or data source providing information related to changes in the position, speed, heading, or orientation of the excavator 20. Sensor systems suitable for monitoring the position and movement of the excavator chassis 28 include: a GPS module; sensors from which the rotation rate of the undercarriage tracks can be calculated; an electronic compass; and MEMS devices (such as accelerometers and gyroscopes) that may be packaged as one or more IMUs. Similarly, in embodiments, the orientation of the excavator chassis 28 relative to gravity (or another reference direction) may be monitored using one or more MEMS devices or tilt sensors (tilt meters) fixed to the chassis 28.

[0032] The implement tracking data source 72 may also include any number and type of boom assembly tracking sensors adapted to track the position and movement of the excavator boom assembly 24. In embodiments, such sensors may include rotary or linear variable displacement transducers integrated into the excavator boom assembly 24. For example, in one possible implementation, a rotary position sensor may be integrated into the pivot joint of the boom assembly 24; and angular displacement readings captured by the rotary position sensor may be combined with known dimensions of the boom assembly 24 (such as those retrieved from memory 48) to track the posture and position of the boom assembly 24 (including the bucket 26) in three-dimensional space. In other cases, the extension and retraction of hydraulic cylinders 38, 40, 42 may be measured (e.g., using linear variable displacement sensors) and used to calculate the current posture and positioning of the excavator boom assembly 24. In addition to or in place of the aforementioned sensor readings, the controller architecture 50 may also consider other sensor inputs, such as inertial-based sensor readings (e.g., sensor readings captured by the IMU incorporated into the boom assembly 24) and / or vision system tracking of the excavator, to name just a few.

[0033] In an implementation, the excavator 20 may also be equipped with a slope control system 74. This slope control system 74 can be integrated into the excavator; or alternatively added to the excavator via aftermarket modifications, such as refurbishment of the external mast and cables. The slope control system 74 can be a two-dimensional or three-dimensional system that uses design data to calculate the cutting edge position of the work vehicle's implements (e.g., bucket 26) based on the current position of the implements and, more generally, the work vehicle in a real-world context. Typically, this is achieved by loading a data file containing the desired terrain layout onto the work vehicle's computer system and associating the desired terrain layout with, for example, the machine's position monitored using a GPS module on the work vehicle. Visual guidance (e.g., on a display device 82 described below) can then be generated, which the operator can rely on when controlling the work vehicle to position the implement's cutting edge in a manner suitable for achieving the desired slope. Such systems are now deployed on excavators, bulldozers, motorized graders, and similar work vehicles commonly used for excavation purposes.

[0034] The non-joystick sensor input 70 may also include one or more sensors that provide data indicating a local ground plane or height. For example, in one embodiment, the excavator 20 may be equipped with a relatively comprehensive (e.g., 360-degree) obstacle detection system, such as using a lidar, radar, or ultrasonic sensor array to provide accurate, wide-range detection of the height of obstacles near the work vehicle. When present, the controller architecture 50 may utilize such an obstacle detection system to estimate the excavation ground height of the chassis 28 of the excavator 20. In other cases, the controller architecture 50 may estimate the ground in different ways; for example, by utilizing a calibration process in which the operator places the bucket 26 on the ground and then estimates the position of the bucket 26. This data may, for example, be used to allow the operator to specify the desired vertical position of a virtual ceiling or virtual base defining such a boundary by inputting data indicating the above-ground or underground height of the upper or lower boundary of the operational envelope.

[0035] In various implementations, the non-joystick sensor input 70 may also include sensors related to obstacle detection. Such sensors can be included in an obstacle detection system that, for example, uses LiDAR, radar, or an ultrasonic sensor array to provide relatively wide-range detection (e.g., 360-degree detection) of obstacles near the work vehicle. In embodiments, such an obstacle detection system can also detect obstacles near the excavator 20 through visual analysis or image processing of field camera feeds provided by one or more cameras located around the excavator 20. This obstacle detection data (such as that collected by an obstacle detection system on the excavator 20) can then be placed on a vehicle bus (e.g., CAN bus 84 described below) or otherwise provided to the controller architecture 50 for consideration in embodiments where the excavator 20 establishes one or more virtual boundaries relative to such obstacles, as discussed further below. Similarly, in embodiments, the controller architecture 50 can retrieve data from memory 48 mapping the positions of obstacles near the excavator 20, which can be associated with the excavator position using GPS or another tracking method. For example, such obstacles may include buried conduits, electrical pipes, or other such structures that need to be avoided during excavation tasks performed using excavator 20. Using such obstacle mapping data retrieved from memory 48 as a geographic reference to the current excavator location, controller architecture 50 can establish virtual walls that define or border an operational envelope, for example, when digging trenches or other excavation features at the location of adjacent buried objects, to keep bucket 26 within this operational envelope.

[0036] Implementations of the MRF joystick system 22 may also include any number of additional non-joystick components 78, such as an operator interface 80, a display device 82 located in the excavator cab 32, and various other unillustrated component types typically included in work vehicles. In particular, the operator interface 80 may include any number and type of non-joystick input devices for receiving operator input, such as buttons, switches, knobs, and similar manual inputs external to the MRF joystick device 52. Such input devices included in the operator interface 80 may also include cursor-type input devices such as trackballs or joysticks for interacting with a graphical user interface (GUI) generated on the display device 82. The display device 82 may be located within the cab 32 and may take the form of any image-generating device on which visual alarms and other information can be visually presented. The display device 82 may also generate a GUI for receiving operator input, or may include other inputs (e.g., buttons or switches) for receiving operator input, which may be related to the controller architecture 50 when performing the processes described below. In some cases, the display device 82 may also have touch input capability.

[0037] As in Figure 1Further schematically depicted, controller architecture 50 is associated with memory 48 and can communicate with various illustrated components via any number of wired data connections, wireless data connections, or any combination thereof; for example, as generally illustrated, controller architecture 50 can receive data from the components via a centralized vehicle bus (such as controller area network (CAN) bus 84). As appears herein, the term "controller architecture" is used in a non-limiting sense to generally refer to the processing subsystem of a work vehicle MRF joystick system such as the example MRF joystick system 22. Thus, controller architecture 50 may encompass or be associated with any actual number of processors, individual controllers, computer-readable storage, power supplies, storage devices, interface cards, and other standardized components. In many cases, controller architecture 50 may include a local controller directly associated with the joystick interface, as well as other controllers housed within an operator's console surrounded by cab 32, and the local controller may communicate with other controllers on excavator 20 as needed. Controller architecture 50 may also include any number of firmware and software programs or computer-readable instructions designed to perform various processing tasks, calculations, and control functions described herein, or may cooperate with firmware and software programs or computer-readable instructions. Such computer-readable instructions may be stored in non-volatile sectors of memory 48 associated with (accessible by) controller architecture 50. Although in Figure 1 While generally exemplified as a single frame, memory 48 can encompass any amount and type of storage medium suitable for storing computer-readable code or instructions, as well as other data used to support the operation of the MRF joystick system 22. In embodiments, memory 48 can be integrated into the controller architecture 50, for example, such as a system-in-package, a system-on-a-chip, or another type of microelectronic package or module.

[0038] A more detailed discussion of the joystick configuration or layout of the excavator 20 will be given, noting that the number of joystick devices included in the MRF joystick system 22, as well as the structural aspects and functions of such joysticks, will differ between implementations. As previously mentioned, although in Figure 1 Only a single joystick 52 is shown schematically, but the MRF joystick system 22 typically has two joysticks 52, 54 supporting control of the excavator boom assembly. This is further illustrated. Figure 2A perspective view from inside the excavator cab 32 is provided, depicting two MRF joystick devices 52, 54 appropriately included in the embodiment of the MRF joystick system 22. As can be seen, the MRF joystick devices 52, 54 are positioned on opposite sides of the operator's seat 86, allowing the operator to relatively easily operate both the left MRF joystick device 52 and the right joystick device 54 simultaneously using both hands. Continuing from the above... Figure 1 By reference numerals, each joystick device 52, 54 includes a joystick 60 mounted to a lower support structure or base housing 62 for rotation relative to the base housing 62 about two vertical axes. Joystick devices 52, 54 also each include a flexible cover or boot 88 engaged between the lower portion of the joystick 60 and their respective base housing 62. Additional joystick inputs are also provided on each joystick 60 in the form of thumb-accessible buttons, and may also be provided on the base housing 62 as other unillustrated manual inputs (e.g., buttons, dials, and / or switches). Figure 2 Other notable features of the excavator 20 shown include the previously mentioned display device 82 and pedal / control lever mechanisms 90, 92, which control the corresponding movement of the left and right tracks of the tracked undercarriage 30.

[0039] Different control schemes can be used to translate the movement of the joysticks 60 included in the joystick devices 51 and 54 into corresponding movements of the excavator boom assembly 24. In many cases, the excavator 20 will support boom assembly control in either "backhoe control" or "SAE control" mode and "International Organization for Standardization" or "ISO" control mode (and usually allows switching between these modes). In the backhoe control mode, moving the left joystick 60 to the operator's left (arrow 94) causes the excavator boom assembly 24 to rotate to the left (corresponding to the counterclockwise rotation of the chassis 28 relative to the tracked underframe 30), moving the left joystick 60 to the operator's right (arrow 96) causes the boom assembly 24 to rotate to the right (corresponding to the clockwise rotation of the chassis 28 relative to the tracked underframe 30), moving the left joystick 60 forward (arrow 98) lowers the boom 34, and moving the left joystick 60 backward (arrow 100) raises the boom 34. Furthermore, in the backhoe control mode, moving the right joystick 60 to the left (arrow 102) causes the bucket 26 to roll inward, moving the right joystick 60 to the right (arrow 104) causes the bucket 26 to uncurl or "open," moving the right joystick 60 forward (arrow 106) causes the bucket handle 36 to rotate outward, and moving the right joystick 60 backward (arrow 108) causes the bucket handle 36 to rotate inward. In contrast, in the ISO control mode, the joystick movements for the swing command and the bucket roll command remain unchanged, while the joystick mappings for the boom and bucket handle are reversed. Therefore, in ISO control mode, moving the left joystick 60 forward and backward controls the bucket handle rotation as described above, while moving the right joystick 60 forward and backward controls the boom 34 movement (raising and lowering) as described above.

[0040] Now, referring to Figure 3 and Figure 4The following figures illustrate an example configuration of the MRF joystick device 52 and the MRF joystick resistance mechanism 56 using two simplified cross-sectional schematic diagrams. While these figures illustrate a single MRF joystick device (i.e., MRF joystick device 52), the following description also applies to another MRF joystick device 54 included in the example MRF joystick system 22. The following description is provided only by way of non-limiting example; note that multiple different joystick designs incorporating or functionally cooperating with the MRF joystick resistance mechanism are possible. The specific composition of the magnetorheological fluid is largely not important to embodiments of this disclosure, provided that a meaningful change in the rheological properties (viscosity) of the magnetorheological fluid occurs in conjunction with a controlled change in the EM field strength (as described below). However, for completeness, it is noted that a magnetorheological fluid composition perfectly suited for use in embodiments of this disclosure comprises magnetically permeable (e.g., iron carbonyl) particles dispersed in a carrier fluid that is primarily composed by weight of oil or alcohol (e.g., ethylene glycol). These magnetically conductive particles can have an average diameter in the micrometer range (or other maximum cross-sectional dimensions if the particles have a non-spherical (e.g., rectangular) shape); for example, in one embodiment, spherical magnetically conductive particles with an average diameter between 1 micrometer and 10 micrometers are used. Various other additives (such as dispersants or diluents) can also be included in the magnetorheological fluid to fine-tune its properties.

[0041] Now, referring to Figure 3 and Figure 4 The example joystick configuration shown, and again continuing with the previously introduced reference numerals as appropriate, the MRF joystick device 52 includes a joystick 60 having at least two distinct portions or structural regions: an upper handle 110 (only a simplified lower portion of this upper handle is shown in the figure), and a generally spherical lower base 112 (hereinafter referred to as "generally spherical base 112"). The generally spherical base 112 of the joystick 60 is captured between two walls 114, 116 of a base housing 62, which may extend generally parallel to each other to form the upper portion of the base housing 62. A vertically aligned central opening is provided through the housing walls 114, 116, and the corresponding diameter of this central opening is adjusted to be smaller than the diameter of the generally spherical base 112. The spacing or vertical offset between the walls 114, 116 is also selected such that the generally spherical base 112 is entirely captured between the vertically spaced housing walls 114, 116 to form a ball-and-socket joint. This allows the joystick 60 to rotate relative to the base housing 62 about two vertical axes, which correspond to the... Figure 3 and Figure 4The coordinate system 118 shows the X and Y axes; it also generally prevents translational movement of the joystick 60 along the X, Y, and Z axes of the coordinate system 118. In other embodiments, various other mechanical arrangements can be used to mount the joystick to the base housing, while allowing the joystick to rotate about two vertical axes (such as a universal joint arrangement). In a less complex embodiment, a pivot or pin joint can be provided to allow the joystick 60 to rotate about a single axis relative to the base housing 62.

[0042] The joystick 60 of the MRF joystick device 52 also includes a stinger or lower joystick extension 120 projecting from a generally spherical base 112 in the opposite direction to the joystick handle 110. In the illustrated schematic, the lower joystick extension 120 is connected to the stationary attachment point of the base housing 62 via a single return spring 124; note that this arrangement is simplified for illustrative purposes, and in actual implementations of the MRF joystick device 52, a more complex spring return arrangement (or other joystick biasing mechanism, if any) will typically be used. When the joystick 60 is... Figure 3 When the gap position or in-situ displacement is shown, such as Figure 4 As shown, the return spring 124 deflects to cause the operating lever 60 to return to its original position. Figure 3 Return. Thus, as an example, when rotating to Figure 4 After the indicated position, if the operator of the work vehicle subsequently releases the control lever 110, the control lever 60 will move towards the indicated position under the influence of the return spring 124. Figure 3 The indicated empty position or return to the original position.

[0043] Example MRF joystick resistance mechanism 56 includes, respectively, as follows: Figure 3 and Figure 4 The first MRF cylinder 126 and the second MRF cylinder 128 are shown. The first MRF cylinder 126 ( Figure 3 It is mechanically engaged between the lower control lever extension 120 and the partially shown static attachment point or basic structural feature 130 of the base housing 62. Similarly, the second MRF cylinder 128 ( Figure 4 The MRF cylinder 126 is mechanically engaged between the lower control lever extension 120 and the static attachment point 132 of the base housing 62, and the MRF cylinder body 128 rotates approximately 90 degrees about the Z-axis of coordinate diagram 118 with respect to the MRF cylinder 126. Due to this structural configuration, the MRF cylinder 126 ( Figure 3 ) can be controlled to selectively resist rotation of the joystick 60 about the X-axis of coordinate diagram 118, while the MRF cylinder 128 ( Figure 4The lever 60 can be controlled to selectively resist rotation about the Y-axis of coordinate diagram 118. Additionally, both MRF cylinders 126 and 128 can be jointly controlled to selectively resist rotation about any axis falling between the X and Y axes and extending in the XY plane. In other embodiments, different MRF cylinder configurations can be used, and more or fewer MRF cylinders can be included; for example, in implementations where it is desired to selectively resist rotation of the lever 60 only about the X-axis or only about the Y-axis, or in implementations where the lever 60 can only rotate about a single axis, a single MRF cylinder or a pair of antagonistic cylinders can be used. Finally, although not shown in the simplified schematic, in further implementations, any number of additional groups or components can be included in the MRF cylinders 126 and 128, or they can be associated with any number of additional components. Such additional components can include sensors that monitor the travel of the cylinders 126 and 128 (if desired) to, for example, track the lever position, instead of the lever sensors 182 and 184 described below.

[0044] MRF cylinders 126 and 128 each include a cylinder body 134 to which pistons 138 and 140 are slidably mounted. Each cylinder body 134 includes a cylindrical cavity or bore 136 in which the end 138 of one of the pistons 138 and 140 is mounted for translational movement along the longitudinal axis or centerline of the cylinder body 134. Around the outer periphery of the cavity or bore, each piston end 138 is fitted with one or more dynamic seals (e.g., O-rings) to sealably engage the inner surface of the cylinder body 134, thereby dividing the bore 136 into two opposing variable-volume hydraulic chambers. Pistons 138 and 140 also each include an elongated piston rod 140 that protrudes from the piston end 138 toward the lower control lever extension 120 of the control lever 60. The piston rod 140 extends through an end cap 142 (again, engaging any number of seals) fixed above the open end of the cylinder body 134 to attach to the lower lever extension 120 at lever attachment point 144. In the exemplary example, lever attachment point 144 takes the form of a pin or pivot joint; however, in other embodiments, more complex joints (e.g., ball joints) may be used to form this mechanical connection. Opposite to lever attachment point 144, the opposite ends of the MRF cylinders 126, 128 are mounted to the corresponding stationary attachment points 130, 132 via ball joints 145. Finally, hydraulic ports 146, 148 are also provided at the opposite ends of the respective MRF cylinder bodies 126, 128 to allow the inflow and outflow of magnetorheological fluid to be combined with the translational movement or stroke variation of the pistons 138, 140 along the respective longitudinal axes of the MRF cylinders 126, 128.

[0045] MRF cylinders 126 and 128 are fluidly interconnected with corresponding MRF valves 150 and 152 via flow line connections 178 and 180, respectively. As with MRF cylinders 126 and 128, MRF valves 150 and 152 are presented identically in the illustrated example, but may be modified in further implementations. Although referred to as "valve" in general terms (particularly considering that the function of MRF valves 150 and 152 is to control the flow of magnetorheological fluid), it will be observed that in the current example, MRF valves 150 and 152 lack valve components and other moving mechanical parts. As a beneficial inference, MRF valves 150 and 152 provide fail-safe operation, as they still allow magnetorheological fluid to pass through them with relatively low resistance in the unlikely event of MRF valve failure. Therefore, if any one or both of the MRF valves 150 and 152 fail for any reason, the ability of the MRF joystick resistance mechanism 56 to apply resistance to limit or inhibit joystick movement may be impaired; however, the joystick 60 will be able to rotate freely about the X and Y axes in a manner similar to conventional non-MRF joystick systems, and the MRF joystick device 52 will generally still be able to control the excavator boom assembly 24.

[0046] In the depicted embodiment, MRF valves 150 and 152 both include a valve housing 154 containing end caps 156 fixed to opposite ends of an elongated cylinder core 158. A generally annular or tubular flow channel 160 extends around the cylinder core 158 and between two fluid ports 162 and 164, which are provided by opposite end caps 156. The annular flow channel 160 is surrounded by a plurality of EM induction coils 166 (extending through these EM induction coils) (hereinafter referred to as "EM coils 166"), which are wound around a paramagnetic holder 168 and have a plurality of axially or longitudinally spaced ferrite rings 170 distributed therefrom. A tubular cover 172 surrounds the assembly and through which a plurality of leads are provided for electrical interconnection with the housed EM coils 166. Figure 3 and Figure 4Lines 174 and 176 schematically represent two such leads and corresponding electrical connections to the power and control source 177. As indicated by arrow 179, the controller architecture 50 is operationally coupled to the power and control source 177 in such a way that it can control the source 177 to change the current supplied to the EM coil 166 or the voltage applied across the EM coil during operation of the MRF joystick system 22. Therefore, this structural arrangement allows the controller architecture 50 to command or control the MRF joystick resistance mechanism 56 to change the intensity of the EM field generated by the EM coil 166. An annular flow channel 160 extends through the EM coil 166 (and may be substantially coaxial with the EM coil) such that when the magnetorheological fluid is guided through the MRF valves 150 and 152, the magnetorheological fluid passes through the center of the EM field.

[0047] The fluid ports 162 and 164 of MRF valves 150 and 152 are fluidly connected to ports 146 and 148 of the corresponding MRF cylinders 126 and 128 via the aforementioned conduits 178 and 180, respectively. The lengths of conduits 178 and 180 are, for example, flexible tubes with sufficient slack to accommodate any movement of the MRF cylinders 126 and 128 caused by the rotation of the operating lever 60. In this regard, consider... Figure 4 Example scenario. In this example, the operator has moved the joystick handle 110 in the operator input direction (indicated by arrow 185), causing the joystick 60 to rotate clockwise about the Y-axis of coordinate diagram 118. In conjunction with this joystick movement, as shown, the MRF cylinder 128 rotates about the ball joint 145 to tilt slightly upwards. Furthermore, along with this operator-controlled joystick movement, the pistons 138 and 140 contained in the MRF cylinder 128 retract, causing the piston end 138 to... Figure 4 The pistons 138 and 140 move to the left (towards attachment point 132). This translational movement of pistons 138 and 140 drives magnetorheological fluid through the MRF valve 152 to accommodate a decrease in volume in the chamber to the left of piston end 138 and a corresponding increase in volume in the chamber to the right of piston end 138. Thus, at any time during this operator-controlled joystick rotation, the controller architecture 50 can change the current supplied to the EM coil 166 or the voltage applied across the EM coil 166 to alter the force resisting the magnetorheological fluid flowing through the MRF valve 152, thereby obtaining the desired MRF resistance to further changes in the stroke of pistons 138 and 140.

[0048] Given the responsiveness of the MRF joystick resistance mechanism 56, the controller architecture 50 can control the resistance mechanism 56 to apply this MRF resistance only briefly, thereby increasing the intensity of the MRF resistance in a predetermined manner (e.g., gradually or progressively), while increasing the piston displacement, or providing various other resistance effects (e.g., tactile detent or pulsating effects), as discussed in detail below. The controller architecture 50 can also control the MRF joystick resistance mechanism 56 to selectively provide resistance effects such as stroke changes in conjunction with the rotation of the joystick 60 about the X-axis of coordinate diagram 118 in conjunction with the pistons 138, 140 in the MRF valve 150. Furthermore, the MRF joystick resistance mechanism 56 can independently change the EM field intensity generated by the EM coil 166 within the MRF valves 150, 152, to allow independent control of the MRF resistance that inhibits the rotation of the joystick about the X and Y axes of coordinate diagram 118.

[0049] The MRF joystick device 52 may also include one or more joystick position sensors 182, 184 (e.g., optical or non-optical sensors or transformers) for monitoring the position or movement of the joystick 60 relative to the base housing 62. In the illustrated example, specifically, the MRF joystick device 52 includes a first joystick position sensor 182 for monitoring rotation of the joystick 60 about the X-axis of coordinate diagram 118. Figure 3 ); and a second joystick position sensor 184 that monitors the rotation of the joystick 60 about the Y-axis of coordinate diagram 118. Figure 4 The data connections between joystick position sensors 182 and 184 and controller architecture 50 are represented by lines 186 and 188, respectively. In a further implementation, the MRF joystick device 52 may include various other components not illustrated, such as an MRF joystick resistance mechanism 56. Where appropriate, such components may include operator input and corresponding electrical connections disposed on the joystick 60 or housing 62, an AFF motor, and pressure and / or flow rate sensors included in the flow loop of the MRF joystick resistance mechanism 56 to best suit a particular application or use.

[0050] As previously emphasized, the above-described embodiment of the MRF joystick device 52 has been provided only as a non-limiting example. In alternative implementations, the construction of the joystick 60 may differ in various aspects. If the MRF joystick resistance mechanism 56 can be controlled by the controller architecture 50 to selectively apply resistance (through rheological changes in the magnetorheological fluid) to suppress movement of the joystick relative to the base shell along at least one DOF, then in a further embodiment, the MRF joystick resistance mechanism 56 also... Figure 3 and Figure 4The example shown differs from the one illustrated. In a further practical application, an EM induction coil similar to or identical to EM coil 166 can be directly integrated into the MRF cylinders 126, 128 to provide the desired controllable MRF resistance effect. In this implementation, magnetorheological fluid flow is allowed between variable-volume chambers within a given MRF cylinder 126, 128 via one or more orifices provided through the piston end 138, either by providing an annulus or a slightly smaller annular gap around the inner surface of the piston end 138 and the cylinder body 134, or by providing a flow channel penetrating the cylinder body 134 or the sleeve itself. Advantageously, this configuration allows for a relatively compact integrated design of the MRF lever resistance mechanism. In contrast, in at least some cases, one or more external MRF valves (such as MRF valves 150, 152) are used. Figure 3 and Figure 4 The use of )) can facilitate cost-effective manufacturing and allow the use of commercially available modular components.

[0051] In other implementations, the MRF joystick device is designed to allow magnetorheological fluid to envelop and act directly on the lower portion of the joystick 60 itself (such as a spherical base 112 in the case of the joystick 60), with an EM coil positioned around the lower portion of the joystick and surrounding the magnetorheological fluid body. In this embodiment, the spherical base 112 may be provided with ribs, grooves, or similar topological features to facilitate displacement of the magnetorheological fluid in conjunction with joystick rotation, wherein energizing the EM coil increases the viscosity of the magnetorheological fluid, thereby impeding fluid flow through a restricted channel provided around the spherical base 112, or it could be due to the direction of the magnetorheological fluid in conjunction with the joystick rotation. Various other designs are also possible in further embodiments of the MRF joystick system 22.

[0052] Regardless of the specific design of the MRF joystick resistance mechanism 56, MRF technology, which selectively generates variable MRF resistance to suppress (resist or prevent) problematic joystick movement, offers several advantages. A primary advantage is the high responsiveness of the MRF joystick resistance mechanism 56 (and typically the MRF joystick resistance mechanism) in terms of the rheology of the magnetorheological fluid and ultimately the MRF resistance that suppresses joystick movement over a highly shortened time period (e.g., in some cases, approximately 1 ms). Accordingly, the MRF joystick resistance mechanism 56 can enable the removal (or at least a significant reduction) of the MRF resistance with equal speed by rapidly decreasing the current flowing through the EM coil and allowing the rheology of the magnetorheological fluid (e.g., fluid viscosity) to return to its normal, unstimulated state. The controller architecture 50 can also control the MRF joystick resistance mechanism 56 to generate MRF resistance with a continuous range of intensity or density within limits, achieved by utilizing corresponding variations in the strength of the EM field generated by the EM coil 166. Advantageously, the MRF joystick resistance mechanism 56 can provide reliable, substantially noiseless operation over extended periods. Additionally, the magnetorheological fluid can be formulated to be inherently non-toxic, such as when the magnetorheological fluid contains carbonyl iron-based particles dispersed in an alcohol- or oil-based carrier fluid, as previously described. Finally, as a further advantage, the aforementioned configuration of the MRF joystick resistance mechanism 56 allows the MRF joystick system 22 to selectively generate a first resistance, thereby preventing the joystick from rotating around a first axis (e.g., Figure 3 and Figure 4 The lever rotates about the X-axis of coordinate diagram 118, while selectively generating a second resistance independent of the first resistance, thereby preventing the lever from rotating about the second axis (e.g., the Y-axis of coordinate diagram 118); that is, so that the first resistance and the second resistance have different values ​​as needed.

[0053] Now, referring to Figure 5 An example process 190, appropriately executed by the controller architecture 50 of the MRF joystick system 22, is shown. This example process 190 selectively alters the MRF resistance inhibiting joystick movement based on the tool's movement relative to one or more virtual boundaries. Process 190 (hereinafter referred to as "tool command guidance process 190") comprises multiple processing steps 192, 194, 196, 198, 200, 202, 204, 206, 208, and 210, each of which is described sequentially below. Steps 204, 206, 208, and 210 are further grouped into a graded MRF force generation subprocess 212. Depending on the specific manner in which the tool command guidance process 190 is implemented, Figure 5The steps illustrated in the examples may require a single process or multiple sub-processes. Furthermore, Figure 5 The steps illustrated and described below are provided by way of non-limiting example only. In an alternative embodiment of the machine command guidance process 190, additional processing steps may be performed, certain steps may be omitted, and / or the illustrated processing steps may be performed in an alternative order.

[0054] In response to the occurrence of a predetermined triggering event, the machine command guidance process 190 begins at step 192. The triggering event could be, for example, a work vehicle (e.g., Figure 1 and Figure 2 The start-up of the excavator 20 shown, or alternatively, can be initiated by operator input requesting the activation of the implement command guidance process 190; for example, in one embodiment, the operator can interact with a GUI generated on the display device 82 to initiate the implement command guidance process 190. In other cases, when it is determined that the work vehicle is engaged in a specific type of work task (such as digging or grading), the controller architecture 50 can automatically (i.e., without operator input) start the implement command guidance process 190. For example, for an excavator (e.g., Figure 1 and Figure 2 In the case of an excavator 20, backhoe, bulldozer, motor grader, or similar work vehicle, the controller architecture 50 can automatically initiate implement command guidance processing 190 when the bucket, bulldozer blade, or similar digging tool attached to the work vehicle is lowered to the ground-penetrating position, when the stabilizer arm of the work vehicle is lowered (in the case of a backhoe), or when the operator provides input indicating an upcoming digging operation. As a further possibility, the controller architecture 50 can initiate implement command guidance processing 190 in response to the detection of different predetermined conditions or events. As another example, in an implementation that establishes a virtual boundary around or adjacent to detected obstacles, when sensors on the work vehicle (e.g., included in...) Figure 1 When the non-joystick sensor 76 shown detects a nearby obstacle near the work vehicle, the controller architecture 50 can begin implement command guidance processing 190.

[0055] After initiating the implement command guidance process 190, the controller architecture 50 proceeds to step 194 and collects relevant non-joystick data inputs used in the remainder of the execution process 190. Such data inputs will typically include receiving current implement tracking data used to monitor the position of the joystick-controlled implement or tool relative to the vehicle body or chassis of the work vehicle. Therefore, in the case of excavator 20, during step 194 of the implement command guidance process 190, data from the boom assembly tracking sensor 72 can be received at the controller architecture 50. The controller architecture 50 then uses this data to estimate the position of the bucket 26 (or other implement) engaged at the external end of the boom assembly 24 within the 3D spatial volume or "tool space" of the adjacent excavator chassis 28. As described above, this implement tracking data can include data captured by accelerometers, gyroscopes, magnetometers, or other such MEMS devices (e.g., as an IMU package), data from inclinometers, or data from similar sensors arranged on the boom assembly 24. Alternatively, the angular displacement of the pivot joint around the boom assembly 24 and / or the linear displacement of the hydraulic cylinders 38, 40, 42 can be considered in conjunction with known kinematics (related to component dimensions) to estimate the positional movement of the bucket 26 in the 3D tool space. As a further possibility, in an embodiment, image analysis from one or more video feeds captured by a vision system can also be utilized for implement movement. Typically, then during step 194 of the implement command guidance process 190, any type of data suitable for tracking and positioning can be collected via the controller architecture 50, and the orientation of the movable implement in 3D space can also be collected.

[0056] Additional data may also be collected during step 194 and taken into account by the controller architecture 50 when establishing the position, orientation, and / or geometry of one or more virtual boundaries within the 3D toolspace, as further considered during the hierarchical MRF force generation subprocess 212 (described below). This may include data collected by onboard sensors (e.g., Figure 1The data provided by the non-joystick sensor 70 of the excavator 20, relating to local ground height, slope, and / or other terrain features, can be determined using ranging equipment or other sensors integrated into the work vehicle. This data can be useful when, for example, using local ground height as a reference point to establish the location of at least one virtual boundary (e.g., the excavation base described below). Operator input data relating to the virtual boundaries can also be input via operator interface 80 and further considered by controller architecture 50 during step 194 of execution of process 190. Such operator input can, for example, specify the desired location and / or orientation of one or more virtual boundaries, such as the underground depth (and possibly slope) of the virtual excavation base, the ground height of the virtual ceiling, or indicate the desired positioning (and possibly orientation), or other data for one or more virtual boundaries.

[0057] The work vehicles are equipped with slope control systems (such as the example excavator 20). Figure 1 In an implementation of the slope control system 74, data from the slope control system can be provided to the controller architecture 50, for example, via a device placed on the vehicle bus 84. The controller architecture 50 can then utilize this data (referred to herein as “slope target data”) to establish the position and orientation of a virtual excavation base (and its geometry, if the virtual excavation base is three-dimensional or non-planar) using the data provided by the slope control system 74. Thus, in this implementation, the work vehicle in question (e.g., a bulldozer or motorized grader) can move relative to the virtual excavation base while the operator uses one or more joystick devices to repeatedly position the work vehicle implement (e.g., a bulldozer blade) to displace the underlying soil (or other material) in a controlled manner, thereby creating a desired surface topology that generally conforms to the virtual excavation base. As a further possibility, when this data is used to generate virtual boundaries, data indicating the location of any adjacent obstacles, such as keep-out zones or virtual barriers that prevent accidental contact between implements and nearby obstacles, can be collected during step 194. Furthermore, this obstacle detection data can be obtained from a suitable sensor array (for example, such as in...). Figure 1 The additional sensor 76 shown includes a sensor array that measures energy signals (e.g., laser pulses, acoustic pulses, or radar pulses) reflected from obstacles near the work vehicle.

[0058] Proceeding to step 198 of the implement command guidance process 190, the controller architecture 50 receives data indicating the current joystick movement and position of one or more MRF joystick devices under consideration. In the case of the example excavator 20, the controller architecture 50 receives data from joystick position sensors 182, 184 describing the movement of the corresponding joysticks 60 included in devices 52, 54. The controller architecture 50 uses this data to determine whether an operationally significant movement of one or more joysticks has occurred during the current iteration of the implement command guidance process 190. If such joystick movement is detected, the controller architecture 50 proceeds to the hierarchical MRF force generation subprocess 212, as described below. Otherwise, the controller architecture 50 proceeds to step 200 and determines whether the current iteration of the implement command guidance process 190 should be terminated; for example, due to the work vehicle stopping, due to continuous inactivity of the joystick-controlled function for a predetermined period of time, or due to the removal of the condition or triggering event that initiated the process 190 in step 192. If it is determined that the machine command guidance process 190 should terminate at step 200, the controller architecture 50 proceeds to step 202, and thus, process 190 terminates. If, conversely, it is determined that the machine command guidance process 190 should continue, the controller architecture 50 returns to step 194, and the above processing steps are repeated.

[0059] In response to the detection of a significant joystick rotation (or other joystick movement) in step 202, the controller architecture 50 proceeds to the hierarchical MRF force generation subprocess 212 of the implement command guidance process 190. (As in...) Figure 5As indicated, controller architecture 50 may, for example, command the MRF joystick resistance mechanism 56 during subprocessing module 212 to generate a range of resistance or stiffness responses based on the proximity of the implement (e.g., bucket 26 of excavator 20) to one or more virtual boundaries established by controller architecture 50 in a real 3D spatial volume. At this point, and as discussed more fully below, a graded MRF force generation subprocessing 212 may be performed to provide a range of MRF resistance responses for implement movement relative to one or more virtual boundaries, such range defining or boarding an operable envelope that will, as desired, constrain the joystick-controlled implement. In other, less complex implementations, controller architecture 50 may control the MRF resistance mechanism 56 to provide a single haptic feedback effect, such as indicating implement movement relative to one or more virtual boundaries. For example, in a simplified approach, controller architecture 50 may command the MRF resistance mechanism to generate a tactile stop, a brief pulsating resistance effect, or a similar effect when a violation of a virtual boundary is detected. Similarly, in other embodiments, controller architecture 50 may control MRF joystick resistance mechanism 56 to otherwise provide a single MRF-applied effect (rather than a graded or gradually changing MRF resistance response of the type described below) to prevent virtual boundary violations; for example, controller architecture 50 may command MRF joystick resistance mechanism 56 to generate maximum MRF resistance to prevent or impede further joystick-controlled machine movement corresponding to the current operator input direction when or just before the machine violates the virtual boundary.

[0060] In the execution of the hierarchical MRF force generation subprocess 212, the controller architecture 50 can determine the location of the virtual boundary in any suitable manner. In some cases, and as discussed above, the controller architecture 50 can utilize operator input data received via the operator interface 80 to establish the location of the virtual boundary. Such operator input can, for example, specify the vertical (e.g., underground) depth of the excavation base, which is the vertical depth at which the joystick-controlled implement is desired to be maintained above the excavation base during the operation. The controller architecture 50 can measure this underground depth from any suitable spatial reference point (such as local ground level) along a vertical axis (parallel to gravity). Similarly, operator input can specify the vertical (e.g., above ground) height at which the implement is desired to be maintained below a virtual ceiling. In some cases, the MRF joystick system 22 can also allow the operator to adjust the slope or orientation of this virtual boundary via interaction with the operator interface 80; for example, by interacting with a GUI generated on the display device 82 to set the slope or inclination of the virtual excavation base, as combined below. Figure 6As described. In other cases, slope control systems (such as...) can be utilized. Figure 1 The slope control system 74 on the example excavator 20 shown provides data to determine the location of this virtual boundary or excavation base, wherein the virtual excavation base has a 2D (planar) or 3D (non-planar) geometry that typically conforms to the target slope data provided by the slope control system.

[0061] In further implementations, and as discussed above, data provided by an obstacle detection system on the work vehicle under consideration can be used to determine the location of one or more virtual boundaries. For example, in the case of example excavator 20, controller architecture 50 can use data received from (e.g., obstacle detection) sensor 76 to establish one or more virtual boundaries, spatially positioning these virtual boundaries to reduce the likelihood of accidental contact between the joystick-controlled implement and detected obstacles (such as the sidewall of a structure, another work vehicle, or another physical object near the work vehicle). This is useful, for example, when using excavator 20 or another work vehicle to excavate a ditch or other adjacent excavation feature against the nearby obstacle. In other cases, controller architecture 50 can retrieve obstacle locations or map data from memory 48 when establishing the spatial locations of one or more virtual boundaries, which are to be used when executing subprocess 212. The controller architecture 50 can then utilize this stored map data to establish virtual boundaries between the machine and any mapped obstacles (e.g., buried conduits, buried electrical pipes, power lines, etc.), thereby helping to maintain the desired spatial offset for no-entry zones between the machine and obstacles, or otherwise reducing the impact on the machine's operation. Figure 1 The possibility of the example excavator 20 accidentally coming into contact with such an obstacle while performing a work task (such as digging a ditch or other excavation feature).

[0062] In step 204 of the hierarchical MRF force generation subprocess 212, the controller architecture 50 determines whether continuous joystick rotation along the operator input direction would cause the joystick-controlled implement to be on the verge of violating a virtual boundary. In one implementation, the controller architecture 50 may determine during step 204 whether any part of the implement (in the case of the exemplary excavator 20, this could be the boom assembly 24) would violate a virtual boundary. In other implementations, the controller architecture 50 may consider only whether a specific part of the joystick-controlled implement (such as the cutting edge of the implement) is currently violating a considered virtual boundary or is at risk of violating a considered virtual boundary. In making this determination, the controller architecture 50 may utilize any suitable processing or spatial modeling techniques (several examples of which have been outlined above) to track the movement of the implement in 3D space relative to one or more virtual boundaries. If, during step 204 of subprocess 212, it is determined that continued joystick rotation (or other movement) in the operator input direction would cause the joystick-controlled machine to be on the verge of violating the virtual boundary, then controller architecture 50 commands MRF resistance mechanism 56 to generate MRF resistance that inhibits continued joystick rotation in the operator input direction. In implementation, controller architecture 50 may command MRF joystick resistance mechanism 56 to generate maximum MRF resistance attempting to prevent further joystick rotation in the operator input direction; or at least to make continued joystick rotation in the operator input direction relatively difficult. Therefore, machine violation of the virtual boundary can be avoided, either by physically preventing joystick movement in the problematic direction or by conveying a very clear tactile signal to the operator to terminate continued joystick rotation in the problematic direction. After applying the desired MRF resistance effect (step 200), controller architecture 50 then proceeds to step 200 to determine whether machine command guidance process 190 should continue or terminate.

[0063] Conversely, if during step 204 it is determined that continuous joystick rotation along the operator input direction will not cause the joystick-controlled machine to approach a virtual boundary violation, then controller architecture 50 proceeds to step 206 of the hierarchical MRF force generation subprocess 212. During step 206, controller architecture 50 evaluates whether continuous joystick rotation along the operator input direction will cause the machine to reach a predetermined proximity to the virtual boundary. If it is determined that this will not happen, controller architecture 50 proceeds to step 200 and again considers whether the current iteration of process 190 should terminate. Otherwise, controller architecture proceeds to step 210 and commands the MRF joystick resistance mechanism 56 to generate increased MRF resistance that impedes joystick movement along the operator input direction. In doing so, MRF joystick system 22 generates an intuitive tactile cue (e.g., communicated to the operator via the relevant joystick device) indicating that the joystick-controlled machine is approaching the virtual boundary. If such MRF resistance has not yet been applied, controller architecture 50 can command MRF joystick resistance mechanism 56 to initially generate MRF resistance that prevents further rotation of the joystick in the operator input direction. Conversely, if such MRF resistance has previously been applied, controller architecture 50 can command MRF joystick resistance mechanism 56 to increase the magnitude of the MRF resistance. In the latter case, the MRF resistance can be increased progressively (stepwise or continuously) to the extent that joystick rotation in the operator input direction continues and the joystick-controlled implement moves incrementally toward the considered virtual boundary. Through multiple iterations of step 210, controller architecture 50 can command MRF joystick resistance mechanism 56 to change the MRF resistance such that as the implement approaches or nears the virtual boundary, the MRF resistance increases approximately proportionally to the distance between the implement and the virtual boundary. After step 210, controller architecture 50 proceeds to step 200 and again determines whether the current iteration of process 190 should terminate or continue.

[0064] When the implement command guidance process 190 is repeatedly executed in the manner described above, the controller architecture 50 of the MRF joystick system 22 selectively commands the MRF joystick resistance mechanism 56 to change the MRF resistance against joystick movement, based at least in part on implement movement relative to one or more virtual boundaries. In doing so, the MRF joystick system 22 provides implement command guidance (e.g., intuitive tactile cues) to the work vehicle operator to slow down (if not stop) joystick movement in the operator input direction when appropriate, thereby violating the virtual boundary prevention. Furthermore, if the controller architecture commands the MRF joystick resistance mechanism to generate maximum MRF resistance, the MRF resistance can be sufficient to make joystick movement in the operator input direction very difficult, or can even physically prevent continuous joystick movement in the problematic direction. In this way, the MRF joystick system 22 can help an operator control the implement via one or more joystick devices, such as assigning a desired slope or topology to the terrain, excavating features to desired dimensions (e.g., desired depth or inclination), reducing the likelihood of undesirable collisions between the implement and nearby obstacles, and / or providing various other functions for guiding the joystick-controlled implement mounted to the work vehicle. For completeness, the following is combined with... Figure 6 The example use case scenario is further described, in which implement command guidance processing 190 can be advantageously executed during the operation of the example excavator 20.

[0065] Figure 6 An example scenario is illustrated, in which the excavator 20 is used to perform a mining or excavation task to create a digging feature 216 within the ground 214 of the work area. In this example, the controller architecture 50 of the MRF joystick system 22 has established a lower virtual boundary or digging base in the 3D tool space, as indicated by the horizontal line 220. The MRF joystick system 22 can operate in a mining depth limit mode to prevent (or at least inhibit) the operator from controlling the implement attached to the boom assembly (here, the bucket 26 attached to the excavator boom assembly 24) to dig the digging feature 216 to an excessive depth. The position and possibly orientation of the digging base 220 can be established based on data retrieved from memory 48 and with reference to the current position of the excavator 20 (e.g., determined from the GPS module on the excavator 20). Alternatively, the position can be established via the operator interface 80 (… Figure 1Operator input data is entered into the MRF joystick system 22 to establish the position of the excavation base 220. For example, in one embodiment, the operator can input the underground level at which the virtual excavation base 220 is desired to be located, or a “set excavation depth.” As shown above, this underground depth is, for example, the depth measured in the downward direction along the vertical axis 224 from a local ground height reference point 218, which is approximately parallel to the direction of gravity. To establish this reference point, the controller architecture 50 can use appropriate sensors (e.g., laser-based sensors or rangefinders included in sensor 76) to measure the local ground height; determine the local ground height using a calibration process in which the operator controls the boom assembly 24 to place the bucket 26 on the ground, wherein the controller architecture 50 then uses data from the boom assembly tracking sensor 72 and the known kinematics of the boom assembly 24 to calculate the local ground height; or estimate the local ground height relative to a default setting of the work vehicle chassis.

[0066] In addition to or instead of establishing a virtual excavation base 220, the controller architecture 50 of the MRF joystick system 22 can establish any number of additional virtual boundaries referenced during subsequent excavation tasks. For example, in one implementation, the controller architecture 50 can also establish an upper boundary or virtual ceiling 226, holding the implement 26 (and perhaps all parts of the boom assembly 24) below it as desired. The controller architecture 50 can establish the position of the virtual ceiling in any suitable manner (including based on operator input or data provided by an obstacle detection system on the excavator 20). In one approach, for example, the MRF joystick system 22 can receive operator input specifying a desired ground height of the virtual ceiling 226 (e.g., measured along a vertical axis 228 extending parallel to the direction of gravity). The aforementioned processing, which adjusts the stiffness or resistance of the MRF joystick based on the implement's proximity to the virtual ceiling 226, can then be performed in a similar manner to that described above. The virtual ceiling 226 can be configured for use in the following scenarios: when the excavator 20 (or another work vehicle) is operating in a closed environment (such as a barn or mine), or when the excavator 20 is operating in an outdoor environment with overhead obstacles (e.g., tree branches or overhanging structural features).

[0067] In various implementations, when generating either or both of the virtual excavation base 220 and virtual ceiling 226, the controller architecture 50 of the MRF joystick system 22 utilizes data provided by the boom assembly tracking sensor 72 to track the position of the excavating tool (here, the excavator bucket 26) relative to these virtual boundaries or thresholds. As previously discussed above in conjunction with step 194 of process 190, the boom assembly tracking sensor 74 can include any type and number of sensors that monitor the movement of the excavating tool relative to the chassis or other fixed reference point of the excavator 20. For example, in one approach, a rotary position sensor is integrated into the pivot joint of the boom assembly 24; and angular displacement readings captured by the rotary position sensor in conjunction with known dimensions of the boom assembly 24 are used to track the position of the excavating tool (bucket 26), and can also specifically track the position of the cutting edge of the bucket 26 in 3D tool space. In addition to or in place of such rotational position readings, other sensor inputs may be considered, such as linear displacements of hydraulic cylinders 38, 40, 42 integrated into boom assembly 24, inertia-based sensor readings (such as those captured by MEMS devices (such as MEMS accelerometers or gyroscopes) incorporated into boom assembly 24), and measurements captured by sensors indicating the current orientation of excavator chassis 28.

[0068] Regardless of the specific method of tracking the bucket 26, the controller architecture 50 repeatedly predicts when operator-commanded movement of the excavator boom assembly 24 will cause the bucket 26 to violate the virtual excavation base 220 (or virtual ceiling 226). When it is determined that operator-commanded movement of the excavator boom assembly 24 will result in violation of the virtual excavation base 220, the controller architecture 50 commands the MRF joystick resistance mechanism 56 to generate MRF resistance that inhibits (or attempts to inhibit) continuous joystick movement in the operator input direction. This provides the work vehicle operator with a visual tactile cue to slow down (if not stop) joystick movement in the operator input direction. Furthermore, when the controller architecture 50 commands the MRF joystick resistance mechanism 56 to generate maximum MRF resistance, the MRF resistance is sufficient to completely inhibit joystick movement in the operator input direction (or at least make such joystick movement relatively difficult). Alternatively, assuming the bucket 26 is within a predetermined distance of the base 220, the controller architecture 50 may also command the MRF joystick resistance mechanism 56 to progressively increase the MRF resistance as the bucket 26 approaches the virtual excavation base 220. A similar approach can be applied to the movement of the bucket 26 relative to the virtual ceiling 226 to help keep the bucket 26 (and possibly other parts of the boom assembly 24) below the virtual ceiling 226.

[0069] In other embodiments, in addition to or instead of the virtual excavation base 220 described above, the MRF joystick system 22 may also enable the operator to establish other virtual (e.g., 2D planar or 3D non-planar) boundaries of the excavation feature. For example, in some cases, the controller architecture 50 may prevent violations of virtual sidewalls of the excavation feature, such as the back side of a trench, during a given excavation operation. Figure 6 The text further indicates this possibility. The excavation feature or trench illustrated therein is given a back face 222, which forms a desired angle (θ) relative to a vertical line 224 extending parallel to the direction of gravity. BF During the operation of excavator 20, as the operator drives the excavator to excavate the digging feature 216, the MRF joystick system can selectively increase the amount of force applied to the joystick 60 for controlling the movement of the boom assembly. Figure 1 and Figure 2 The MRF resistance prevents or at least halts penetration of the back face 222. Therefore, tactile cues can be generated and communicated via appropriate joystick devices to help the operator shape the surface of the excavation feature 216 at the desired angle. This can be particularly useful in the case of the trench back face 222, assuming the operator cannot directly observe it from the cab 32 of the excavator 20. Similarly, in an embodiment, the desired slope can be defined via a virtual excavation base 220, or it can be a non-planar 3D geometry, where the MRF joystick system then applies changes in MRF resistance to help the operator control the boom assembly 24 to excavate the excavation feature 216 to conform to the desired excavation base. Similar methods can be used to provide tactile cues to help the operator create the desired gradient in the case of other work vehicles equipped with integrated grade control (IGC) systems (e.g., bulldozers or motorized graders), as follows: Figure 7 Further discussion is needed.

[0070] Additional examples of work vehicles advantageously equipped with the MRF joystick system

[0071] Therefore, the preceding content has described examples of MRF joystick systems that provide implement command guidance by mitigating key variations in MRF resistance that impede movement of the joystick along one or more DOFs. While the preceding description has primarily focused on specific types of work vehicles (excavators) including specific types of joystick-controlled implements, the implementations of the MRF joystick systems described herein are suitable for integration into a wide range of work vehicles that include joystick devices for controlling implement movement, such as the movement of a bucket (or other implement) attached to the end of an articulated boom assembly, the movement of a bucket attached to the end of an FEL assembly, or the movement of a bulldozer blade movably engaged with the chassis of a motorized grader, bulldozer, or another work vehicle, to name just a few. Figure 7 The left side illustrates an example work vehicle, and the right side illustrates an example MRF joystick device. Specifically... Figure 7 The left side illustrates three additional examples of such work vehicles, including a tracked excavator 230, a motorized grader 232, and a backhoe loader 234.

[0072] Firstly, regarding the tracked bulldozer 230, the tracked excavator 230 can be equipped with an example MRF joystick device 236 housed within the operator's cab 238 of the excavator 230. Operator movement of the joystick 240 included in the MRF joystick device 236 can position the bulldozer blade 242 of the bulldozer 230, which is pivotally engaged to the bulldozer chassis 244 and the track underframe 246 via a pusher 248 and a plurality of hydraulic cylinders 250, 252. Specifically, during operation of the tracked bulldozer 230, rotation of the joystick 240 relative to the base of the MRF joystick device 236 can position the blade 242 via the extension and retraction of the pitch cylinder 250 and the lift cylinder 252. The above combination... Figure 1 The various components described are integrated into the tracked bulldozer 230 to provide MRF-applied guidance to a joystick input for controlling the movement and positioning of the bulldozer blade 242 (more generally, the "excavator" or "tool") in the manner described above. For example, in one implementation of the tracked bulldozer 230 equipped with a slope control system, the MRF joystick system, including the MRF joystick device 236, can change the joystick stiffness to assist the operator in positioning the blade 242 to achieve a desired slope as the tracked bulldozer 230 moves within the work area.

[0073] Next, we turn to the example motorized grader 232. Two MRF (Mechanical Radio Frequency) joystick devices 254 are housed within the cab 256 of the motorized grader 232. Rotation of the joysticks 258 included in the MRF joystick devices 254 positions the shovel 260 suspended below a circle 262, which is mounted below the front frame 264 of the motorized grader 232. Together, the shovel 260 and the circle 262 form a blade-circle assembly 260, 262. In this configuration, rotation of the joysticks 258 relative to their respective base shells can control the shovel position 260 via rotation of the circle rotary motor 266, along with changes in the stroke (extension and retraction) of the hydraulic cylinder 268. During operation of the motorized grader 232, the MRF joystick system selectively alters the MRF resistance against the rotation of the joystick 258 to guide implement movement, and specifically guides joystick movement to control the rotation of the shovel-ring assemblies 260, 262, the angle adjustment of the shovel-ring assemblies 260, 262, and the adjustment of the lateral angle of the shovel 260. Similar to the tracked bulldozer 230, the motorized grader 232 may be equipped with an IGC system (or a treadmill slope control system) that provides data indicating the desired slope to the controller architecture of the MRF joystick system as the motorized grader 232 moves across the work area. The MRF joystick system then uses the target slope data provided by the slope control system to establish a virtual boundary corresponding to the desired slope and alters the MRF resistance applied to the joystick 258, at least in part, based on implement movement relative to the virtual boundary. In this way, intuitive tactile feedback is provided to the operator when the shovel 260 is positioned at the appropriate time to achieve the desired target slope.

[0074] Finally refer to Figure 7The backhoe loader 234 depicted at the bottom may house one or more MRF joystick devices 270 in the cab 272 of the backhoe loader 234. In this example, rotation of one or more joysticks 274 included in one or more MRF joystick devices 270 may be used to: control the movement of the FEL assembly 276, which terminates at the FEL bucket 278 and is engaged with the front end of the loader chassis 280; control the movement of the backhoe assembly 282, which terminates at the FEL bucket 284 and is engaged with the rear end of the loader chassis 280; or both. The MRF joystick devices 270 may be controlled by the MRF joystick system described above to assist the operator in controlling the FEL assembly 276, the backhoe assembly 282, or both, to excavate the digging feature to a desired size (e.g., a desired depth), avoid unintentional contact with nearby obstacles, or perform other functions. Specifically, in the case of backhoe assembly 282, the MRF lever system on backhoe loader 234 can change the MRF resistance of MRF lever device 270 to achieve a similar effect to the above combination. Figure 1 and Figure 2 The example excavator shown illustrates the manner in which the implement is guided. In contrast, in the case of FEL assembly 276, when the backhoe loader 234 is operating inside a barn or another enclosed structure, the MRF joystick system can also increase the MRF resistance of the MRF joystick device 270 to, for example, prevent (or at least block) operator joystick commands to bring the FEL bucket 278 to a raised position above the virtual ceiling.

[0075] Examples of MRF joystick systems for work vehicles

[0076] For ease of reference, the following examples of MRF joystick systems for work vehicles are also provided and numbered.

[0077] 1. In one embodiment, a work vehicle MRF joystick system includes: a joystick device, a tool tracking data source, an MRF joystick resistance mechanism, and a controller architecture. The joystick device further includes: a base housing; a joystick mounted to the base housing and movable relative to the base housing; and a joystick position sensor configured to monitor joystick movement relative to the base housing. The tool tracking data source is configured to track the movement of the tool during operation of the work vehicle, while the MRF joystick resistance mechanism can be controlled to change the MRF resistance that impedes joystick movement relative to the base housing. The controller architecture, coupled to the MRF joystick resistance mechanism, the joystick position sensor, and the tool tracking data source, is configured to: (i) track the movement of the tool relative to a virtual boundary using data provided by the tool tracking data source; and (ii) command the MRF joystick resistance mechanism to change the MRF resistance, at least in part, based on the tool movement relative to the virtual boundary.

[0078] 2. The MRF joystick system for the work vehicle according to Example 1, wherein the work vehicle is equipped with a slope control system. The controller architecture is coupled to the slope control subsystem, and the controller architecture is configured to define the virtual boundary using slope target data provided by the slope control system.

[0079] 3. The work vehicle MRF joystick system according to Example 2, wherein the work vehicle includes a bulldozer or a motorized grader, the implement is in the form of a shovel, and the virtual boundary defines a virtual excavation base.

[0080] 4. The MRF joystick system for the work vehicle according to Example 1, wherein the virtual boundary takes the form of a virtual excavation base. Furthermore, the controller architecture is configured to establish the position and orientation of the virtual excavation base in the 3D tool space through which the implement moves.

[0081] 5. The MRF joystick system for the work vehicle according to Example 4, wherein the controller architecture establishes the position of the virtual excavation base based at least in part on a set excavation depth and a ground height reference point.

[0082] 6. The work vehicle MRF joystick system according to Example 4, wherein the controller architecture is at least partially based on operator input to establish the orientation of the virtual excavation base, the operator input indicating a target slope for the excavation features to be created by the implement as desired.

[0083] 7. The work vehicle MRF joystick system according to Example 1, wherein the controller architecture is configured to gradually increase the MRF drag as the implement approaches the virtual boundary.

[0084] 8. The MRF joystick system for a work vehicle according to Example 1, wherein the controller architecture is configured to: (i) detect joystick movement in the operator input direction; (ii) when joystick movement in the operator input direction is detected, determine whether continuous joystick movement in the operator input direction would cause the implement to immediately violate the virtual boundary; and (iii) when it is determined that continuous joystick movement in the operator input direction would cause an imminent or immediate violation of the virtual boundary, issue a command to the MRF joystick resistance mechanism to generate maximum MRF resistance to substantially stop continuous joystick movement in the operator input direction.

[0085] 9. The work vehicle MRF joystick system according to Example 8, wherein the controller architecture is further configured to: (i) when determining that continuous joystick movement along the operator input direction will not cause an immediate violation of the virtual boundary, further determine whether continuous joystick movement along the operator input direction will cause the implement to reach a predetermined proximity to the virtual boundary; and (ii) when determining that continuous joystick movement along the operator input direction will cause the implement to reach a predetermined proximity to the virtual boundary, issue a command to the MRF joystick resistance mechanism to generate an MRF resistance smaller than the maximum MRF resistance that hinders continuous joystick movement along the operator input direction.

[0086] 10. The MRF joystick system for a work vehicle according to Example 1, wherein the controller architecture is configured to: (i) detect joystick movement in the operator input direction; (ii) when joystick movement in the operator input direction is detected, determine whether continuous joystick movement in the operator input direction would cause the implement to immediately violate the virtual boundary; and (ii) when it is determined that continuous joystick movement in the operator input direction would cause an immediate violation of the virtual boundary, issue a command to the MRF joystick resistance mechanism to generate a stopping effect or a pulsating effect as the implement crosses the virtual boundary.

[0087] 11. The work vehicle MRF joystick system according to Example 1, wherein the work vehicle includes a boom assembly having a terminal to which the implement is attached. The controller architecture is configured to: (i) monitor joystick-commanded movement of the boom assembly; and (ii) determine, at least in part, based on the joystick-commanded movement of the boom assembly, whether continuous movement of the joystick along the operator input direction would result in a violation of a virtual boundary.

[0088] 12. The work vehicle MRF joystick system according to Example 11, wherein the virtual boundary includes a virtual ceiling, and the implement is held under the virtual ceiling as desired.

[0089] 13. The work vehicle MRF joystick system according to Example 12, the work vehicle MRF joystick system further includes an operator interface coupled to the controller architecture. The controller architecture is configured to locate the virtual ceiling at least in part based on operator data specifying a ceiling height input by an operator via the operator interface.

[0090] 14. The work vehicle MRF joystick system according to Example 1, wherein the controller architecture is further configured to: (i) estimate the spatial position of an obstacle relative to the work vehicle; and (ii) establish the position of the virtual boundary based at least in part on the estimated spatial position of the obstacle, such that the virtual boundary is located between the implement and the work vehicle.

[0091] 15. The work vehicle MRF joystick system according to Example 1, wherein the controller architecture is configured to issue a command to the MRF joystick resistance mechanism to change the MRF resistance such that as the implement approaches the virtual boundary, the MRF resistance increases substantially proportionally to the distance between the implement and the virtual boundary.

[0092] in conclusion

[0093] Therefore, implementations of an MRF joystick system have been described that guide the joystick-controlled positioning of a work vehicle implement by intelligently applying variations in forces applied via the MRF. In various implementations, the MRF joystick system can selectively impede or inhibit joystick movement based on implement movement relative to one or more virtual boundaries. This, in turn, helps or guides the operator to command implement movement with greater precision, increased efficiency, and, in some cases, reduced likelihood of unwanted collisions with any nearby obstacles when using one or more joysticks. In implementations, the virtual boundaries can partially define or border an operable envelope, thereby maintaining the implement within that operable envelope as desired during a specific work task, such as a digging task. In other implementations, the virtual boundaries can be generated to conform to or substantially conform to the final slope topology or profile of the surface on which the work vehicle (e.g., a bulldozer or motorized grader) is traveling, in which case one or more virtual boundaries can be defined using a slope control system on the work vehicle, if present. In other cases, virtual boundaries can be used to set other thresholds that define restricted areas or zones that joystick-controlled equipment is expected to not intrude into; for example, when one or more virtual boundaries are established around a buried object, above-ground structure, or other obstacle, the virtual boundaries are intended to prevent equipment attached to a work vehicle from unintentionally operating near such obstacle.

[0094] As used herein, unless the context clearly indicates otherwise, the singular form of the description is intended to include the plural form. It should also be understood that, when used herein, the term “comprise and / or comprising” specifies the presence of a prescribed feature, element, step, operation, element, and / or component, rather than excluding the presence or addition of one or more other features, elements, steps, operations, elements, components, and / or combinations thereof.

[0095] The description of this disclosure has been presented for purposes of illustration and description, but is not intended to be exclusive or to limit the disclosure to its disclosed form. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of this disclosure. The embodiments expressly referenced herein were chosen and described in order to best explain the principles of this disclosure and its practical application, and to enable those skilled in the art to understand this disclosure and recognize many alternatives, modifications, and variations to the described examples. Therefore, various other embodiments and implementations besides those expressly described are within the scope of the appended claims.

Claims

1. A work vehicle magnetorheological fluid joystick system (22) for use on a work vehicle (20) equipped with implements (26), namely, a work vehicle MRF joystick system (22), the work vehicle MRF joystick system (22) comprising: The joystick devices (52, 54) include: Base shell (62); A joystick (60) is mounted to the base housing (62) and is movable relative to the base housing (62); and A joystick position sensor (66) is configured to monitor joystick movement relative to the base housing (62); A tool tracking data source (72) is configured to track the movement of the tool (26) during the operation of the work vehicle (20); MRF joystick resistance mechanism (56), which can be controlled to change the MRF resistance that hinders joystick movement relative to the base housing (62); and Controller architecture (50), which is connected to the MRF joystick resistance mechanism (56), the joystick position sensor (66), and the implement tracking data source (72), is configured to: The movement of the machine (26) relative to the virtual boundary is tracked using data provided by the machine tracking data source (72); and The MRF joystick resistance mechanism (56) is commanded to change the MRF resistance, at least in part, based on the movement of the machine relative to the virtual boundary.

2. The MRF joystick system (22) for the work vehicle according to claim 1, wherein, The work vehicle (20) is equipped with a slope control system (74); and The controller architecture (50) is connected to the slope control system (74), and the controller architecture (50) is configured to define the virtual boundary using slope target data provided by the slope control system (74).

3. The MRF joystick system (22) for the work vehicle according to claim 2, wherein, The work vehicle (20) includes a bulldozer (230) or a motorized grader (232), the implement (26) includes shovels (242, 260), and the virtual boundary defines a virtual excavation base.

4. The MRF joystick system (22) for the work vehicle according to claim 1, wherein, The virtual boundary includes a virtual excavation base (220); and The controller architecture (50) is also configured to establish the position and orientation of the virtual excavation base (220) in the three-dimensional 3D tool space through which the tool (26) moves.

5. The MRF joystick system (22) for the work vehicle according to claim 4, wherein, The controller architecture (50) establishes the location of the virtual excavation base (220) based at least in part on a set excavation depth and ground height reference point.

6. The MRF joystick system (22) for the work vehicle according to claim 4, wherein, The controller architecture (50) establishes the orientation of the virtual excavation base (220) at least in part based on operator input, which indicates the target slope of the excavation feature to be created as desired using the implement (26).

7. The MRF joystick system (22) for the work vehicle according to claim 1, wherein, The controller architecture (50) is configured to gradually increase the MRF resistance as the machine (26) gets closer to the virtual boundary.

8. The MRF joystick system (22) for the work vehicle according to claim 1, wherein, The controller architecture (50) is configured as follows: Detect joystick movement in the direction of operator input; When joystick movement in the operator input direction is detected, it is determined whether continued joystick movement in the operator input direction would cause the machine (26) to be on the verge of violating the virtual boundary; and When it is determined that continuous joystick movement along the operator input direction would result in an immediate violation of the virtual boundary, a command is issued to the MRF joystick resistance mechanism (56) to generate maximum MRF resistance to substantially stop continuous joystick movement along the operator input direction.

9. The MRF joystick system (22) for the work vehicle according to claim 8, wherein, The controller architecture (50) is also configured to: When it is determined that continuous joystick movement along the operator input direction will not cause an immediate violation of the virtual boundary, it is further determined whether continuous joystick movement along the operator input direction will cause the machine (26) to reach a predetermined proximity to the virtual boundary; and When it is determined that continuous joystick movement along the operator input direction will cause the machine (26) to reach a predetermined proximity to the virtual boundary, a command is issued to the MRF joystick resistance mechanism (56) to generate an MRF resistance smaller than the maximum MRF resistance that hinders continuous joystick movement along the operator input direction.

10. The MRF joystick system (22) for the work vehicle according to claim 1, wherein, The controller architecture (50) is configured as follows: Detect joystick movement in the direction of operator input; When joystick movement in the operator input direction is detected, it is determined whether continued joystick movement in the operator input direction would cause the machine (26) to immediately violate the virtual boundary; and When it is determined that continuous joystick movement along the operator input direction would result in an immediate violation of the virtual boundary, a command is issued to the MRF joystick resistance mechanism (56) to generate a stopping effect or a pulsating effect as the implement (26) crosses the virtual boundary.

11. The MRF joystick system (22) for the work vehicle according to claim 1, wherein, The work vehicle (20) includes a boom assembly (24) having a terminal to which the implement (26) is attached; and The controller architecture (50) is configured as follows: Monitor the movement of the boom assembly (24) via joystick commands; and The determination of whether continuous movement of the joystick in the operator input direction would cause the implement (26) to violate the virtual boundary is based at least in part on the movement of the boom assembly (24) via joystick command.

12. The MRF joystick system (22) for the work vehicle according to claim 11, wherein, The virtual boundary includes a virtual ceiling (226), under which the machine (26) is held as desired.

13. The work vehicle MRF joystick system (22) according to claim 12, wherein the work vehicle MRF joystick system (22) further includes an operator interface (80) connected to the controller architecture (50); and in, The controller architecture (50) is configured to locate the virtual ceiling at least in part based on operator data, which specifies the ceiling height input by the operator via the operator interface (80).

14. The MRF joystick system (22) for the work vehicle according to claim 1, wherein, The controller architecture (50) is also configured to: Estimate the spatial position of the obstacle relative to the work vehicle (20); and The location of the virtual boundary is established at least in part based on the estimated spatial location of the obstacle, such that the virtual boundary is located between the machine (26) and the work vehicle (20).

15. The MRF joystick system (22) for the work vehicle according to claim 1, wherein, The controller architecture (50) is configured to issue a command to the MRF joystick resistance mechanism (56) to change the MRF resistance such that as the implement (26) approaches the virtual boundary, the MRF resistance increases approximately proportionally to the distance between the implement (26) and the virtual boundary.

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