System and Method for Predictively Mitigating the Impacts of Travel Across Uneven Terrain by a Work Machine

The present disclosure relates to work machines having work implements for carrying material and capable of movement relative to a frame thereof. More particularly, the present disclosure relates to systems and methods for automatically predicting the impacts of traverse over uneven terrain by the work machine, and dynamically controlling one or more work machine operating parameters to mitigate these impacts.

Work machines as discussed herein relate primarily to skid steer loaders, compact track loaders, four-wheel drive loaders, or other equivalent load-carrying machines for reasons as further described below, but may in various embodiments apply as well to other work machines which may travel across rough or otherwise uneven terrain during operation.

When such work machines travel over rough terrain, the riding condition for an operator of the work machine, or the carrying condition for material being carried by a work implement thereof (e.g., a bucket), is also rough due to forces acting on the work machine which create shocks. In addition to the relative discomfort experienced by the operator and corresponding effects on productivity, these shocks may cause material to spill out of bucket due to this rough ride, and/or material density may be loosened, either of which ultimately further impacts productivity.

For many such work machines, these forces may result where fluid in cylinders, for example as actuators for movement of the corresponding work implements, cause the cylinders to act as rigid members.

It would accordingly be desirable to improve upon existing ride control systems with system optimization for more inputs to control ride control functions, preferably to provide consistent performance in all terrains and speeds.

The current disclosure provides an enhancement to conventional systems, at least in part by enabling a ride control system and method through software and corresponding automated functions on a work machine, in various embodiments as implemented further in view of back-end models iteratively developed for retrieval by the work machine, further utilizing various sensors (e.g., perception sensors) already provided on the work machine and preferably limiting dependency on supplemental components.

Such a system and method as disclosed herein may enable ride control functions that desirably provide consistent performance in substantially any type of terrain and/or advance speed of the work machine.

In an embodiment, a method is disclosed herein for predictively mitigating the impacts of travel across uneven terrain by a work machine having at least one ground engaging mechanism and at least one implement configured to carry a load and movable across a range of positions relative to a frame of the work machine. During an iterative model development stage, first input data sets corresponding to one or more terrain characteristics and to one or more work machine operating values are correlated with further input data sets corresponding to one or more observed impacts, wherein the one or more work machine operating values comprise a work implement position, and wherein the one or more observed impacts comprise a detected vibration and/or a detected change in one or more load characteristics. During a current operation, input signals are received from one or more perception sensors corresponding to one or more terrain characteristics in at least a forward direction relative to the work machine, from one or more position sensors corresponding to a current position of the at least one work implement relative to the work machine frame, and from one or more load sensors corresponding to one or more characteristics of a current load being carried by the at least one work implement. The method further includes predicting one or more impacts to result from travel across the terrain in the at least forward direction, based on the received input signals during the current operation and the correlated one or more observed impacts as retrieved from the model, and dynamically controlling one or more work machine operating values during travel by the work machine across the terrain based at least on the predicted one or more impacts.

In one exemplary aspect according to the above-referenced method embodiment, the dynamically controlled one or more work machine operating values may comprise a position of the at least one work implement relative to the frame of the work machine.

In another exemplary aspect according to the above-referenced method embodiment, and optionally further according to other aspects as referenced herein, the dynamically controlled one or more work machine operating values may comprise a travel speed of the work machine.

In another exemplary aspect according to the above-referenced method embodiment, and optionally further according to other aspects as referenced herein, the method may comprise receiving input signals during the current operation corresponding to a current location of the work machine, and predicting the one or more impacts further based on previously mapped terrain characteristics associated with the current location of the work machine.

In another exemplary aspect according to the above-referenced method embodiment, and optionally further according to other aspects as referenced herein, the method may comprise automatically enabling the predicting of the one or more impacts and the dynamically controlling of the one or more work machine operating values based on a determination that a threshold load is exceeded via the one or more characteristics of the current load, and further based on a determination that the work machine is traveling.

In another exemplary aspect according to the above-referenced method embodiment, and optionally further according to other aspects as referenced herein, the method may comprise automatically disabling the predicting of the one or more impacts and the dynamically controlling of the one or more work machine operating values based on a determination that the at least one work implement is unloaded, or that the work machine is stopped.

In another exemplary aspect according to the above-referenced method embodiment, and optionally further according to other aspects as referenced herein, the one or more characteristics of the current load may comprise a total mass, a total volume, and/or a type of material being carried by the at least one work implement.

In another exemplary aspect according to the above-referenced method embodiment, and optionally further according to other aspects as referenced herein, the method may comprise, during the current operation, receiving the input signals from the one or more perception sensors further corresponding to one or more terrain characteristics in one or more buffer zones relative to the at least forward direction, and further predicting one or more impacts to result from travel across the terrain via the one or more buffer zones.

The dynamically controlled one or more work machine operating values during travel by the work machine across the terrain may further correspond to steering along a selectively modified path of the work machine via at least one of the one or more buffer zones based at least on the predicted one or more impacts.

In another exemplary aspect according to the above-referenced method embodiment, and optionally further according to other aspects as referenced herein, the one or more work machine operating values may be dynamically controlled to target values set according to a selected optimization mode from a plurality of selectable optimization modes.

At least one of the plurality of optimization modes may for example be configured to minimize vibration associated with the machine frame responsive to predicted impacts while remaining within a specified range of values for one or more other work conditions.

At least one of the plurality of optimization modes may as another example be configured to maximize values for one or more other work conditions while remaining within a specified range of values for vibration associated with the machine frame.

In another exemplary embodiment as disclosed herein, a computer-implemented system is provided for predictively reducing the impacts of travel across uneven terrain by a work machine having at least one ground engaging mechanism and at least one implement configured to carry a load and movable across a range of positions relative to a frame of the work machine, the system comprising one or more processors configured to direct the performance of steps in the above-referenced method embodiment and optionally one or more of the described aspects thereof.

In one exemplary aspect according to the above-referenced system embodiment, at least one of the one or more processors comprises a remote server functionally linked to a controller of the work machine comprising another of the one or more processors.

Numerous objects, features and advantages of the embodiments set forth herein will be readily apparent to those skilled in the art upon reading of the following disclosure when taken in conjunction with the accompanying drawings.

Referring now to the drawings and particularly to, a representative work machine is shown and generally designated by the number. It may be understood that the work machinecould be one of many types of work machines, including, and without limitation, a skid steer loader, a four wheel drive (WD) loader, an excavator, a backhoe loader, a bulldozer, and other construction vehicles, having distinctions in their respective components and as may be appreciated by one of skill in the art. The work machine , as shown, has a frameextending in a fore-aft directionwith a front-end sectionand a rear-end section. The work machine includes a ground-engaging mechanismthat supports the frameand an operator cabsupported on the frame, wherein the ground-engaging mechanism is configured to support the frame on a surface .

An engine (not shown) may be coupled to the frameand operable to move the work machine. The illustrated work machineincludes tracks as the ground engaging mechanism, but other embodiments can include one or more wheels that engage the surface. The work machinemay be operated to engage the surfaceand cut and move material to achieve simple or complex features on the surface.

As used herein, directions with regard to work machinemay be referred to from the perspective of an operator seated within the operator cab ; the left of work machine  is to the left of such an operator, the right of work machine is to the right of such an operator, the front or fore of work machine is the direction such an operator faces, the rear or aft of work machine is behind such an operator, the top of work machine is above such an operator, and the bottom of work machine below such an operator. In order to turn, the ground-engaging mechanism  on the left side of the work machine may be operated at a different speed, or in a different direction, from the ground-engaging mechanismon the right side of the work machine. In a conventional track loader, the operator can manipulate controls from inside an operator cabto drive the tracks on the right or left side of the work machine . Rotation for work machine may be referred to as rollor the roll direction, pitch  or the pitch direction, and yaw  or the yaw direction.

A user interface(further represented in) may be located within the operator cabfor use by an operator of the work machine. The user interfacemay include or otherwise be functionally linked to one or more corresponding user interface toolsfor input and/or output with respect to a controlleras further described below. Such user interface toolsmay for example include a plurality of user selectable touch buttons (e.g., soft buttons), to select from a plurality of commands or menus, each of which may be selectable through a touch screen having a display unit. Touch buttons respond to touch and do not include a mechanical component requiring a force sufficient to engage mechanical features. The touch screen may be a graphical user interface configured to display icons as well as content of work machine applications. The display unitmay be configured to display in the touch screen still images, moving images, and video content through one or more different types of displays. The display unitmay include, but is not limited, to cathode ray tube (CRT) displays, light-emitting diode (LED) displays, and liquid crystal displays (LCD).

Such an onboard user interfacemay be provided as part of or otherwise functionally linked to a vehicle control systemvia for example a CAN bus arrangement or other equivalent forms of electrical and/or electro-mechanical signal transmission. Another form of user interface (not shown) may take the form of a display unit that is generated on a remote (i.e., not onboard) computing device, which may display outputs such as status indications and/or otherwise enable user interaction such as the providing of inputs to the system. In the context of a remote user interface, data transmission between for example the vehicle control systemand the user interface may take the form of a wireless communications system and associated components as are conventionally known in the art.

The user interfacemay further include, or as may be as separately defined with respect to operator-accessible interface tools, an accelerator pedal which enables the operator to adjust the speed of the vehicle. In other embodiments, a hand lever provides this function. Other exemplary tools residing in or otherwise accessible from the operator cabmay include a steering wheel, a plurality of operator selectable touch buttons configured to enable the operator to control the operation and function of the work machine, and any accessories or implements being driven by the powertrain of the work machine, including for example the work implement.

The work machine  comprises a boom assemblycoupled to the frame. A work implement, for example including one or more work tools at a ground engaging end thereof, may be pivotally coupled at a forward portionof the boom assembly, while a rear portionof the boom assemblyis pivotally coupled to the frame. The frameas represented comprises a main frame  and a track frame . The work implementis illustrated as comprising a bucketfor carrying material, but may further or alternatively be or comprise any number of work tools such as a blade, forks, an auger, a drill, or a hammer, just to name a few possibilities. The work implementmay be coupled to the boom assemblythrough an attachment couplerwhich may be coupled to a distal section of the lift arms, or more specifically a portion of the boom arms in the forward portionof the boom assembly .

The boom assemblycomprises a first pair of lift armspivotally coupled to the frame(one each on a left side and a right side of the operator cab) and moveable relative to the frameby a pair of first hydraulic cylinders, wherein the pair of first hydraulic cylindersmay also conventionally be referred to as a pair of lift cylinders (one coupled to each boom arm). The attachment couplermay be coupled to a forward sectionof the pair of lift arms, being moveable relative to the frameby a pair of second hydraulic cylinders, which may be referred to as tilt cylinders. The frameof the work machinefurther comprises a hydraulic coupleron the front-end portionof the work machineto couple one or more auxiliary hydraulic cylinders (not shown) to drive movement of or actuate auxiliary functions of a work implement. The attachment couplerenables the mechanical coupling of the work implementto the frame. The hydraulic coupler, contrary to the attachment coupler, enables the hydraulic coupling of an auxiliary hydraulic cylinder(s) on the work implementto a hydraulic (implement control) system of the work machine . It may be understood that not all work implementswill have one or more auxiliary hydraulic cylinders and therefore may not use the hydraulic coupler. In some embodiments, the hydraulic couplermay open or close a grapple type work implement, or spin a roller brush type work implement.

Each of the pair of first hydraulic cylinders, the pair of second hydraulic cylinders, and any auxiliary cylinders if applicable when found on the work implementmay be double acting hydraulic cylinders. One end of each cylinder may be referred to as a head end, and the end of each cylinder opposite the head end may be referred to as a rod end. Each of the head end and the rod end may be fixedly coupled to another component, such as a pin-bushing or pin-bearing coupling, to name but two examples of pivotal connections. As a double acting hydraulic cylinder, each may exert a force in the extending or retracting direction. Directing pressurized hydraulic fluid into a head chamber of the cylinders will tend to exert a force in the extending direction, while directing pressurized hydraulic fluid into a rod chamber of the cylinders will tend to exert a force in the retracting direction. The head chamber and the rod chamber may both be located within a barrel of the hydraulic cylinder, and may both be part of a larger cavity which is separated by a moveable piston connected to a rod of the hydraulic cylinder. The volumes of each of the head chamber and the rod chamber change with movement of the piston, while movement of the piston results in extension or retraction of the hydraulic cylinder.

For a work machineas represented in, it may be appreciated that different potential positionsof the boom assemblyand more particularly the lift armsthereof correspond to an available trajectory of movement between a fully lowered positionA and a fully raised positionB. In the fully lowered positionA, for example, the work implementmay be set to a level position with the ground surfacesuch that a plane defined by a bottom portion of the bucketis substantially flush with the ground and is substantially horizontal. However, under some conditions, the work implementmay be capable of being lowered further than the illustrated positionA if for example the surface of the ground beneath the work implementis lower than the surface of the ground engaging mechanismsupon which the work machineis located.

It may further be appreciated that a current positionof the work implementinfluences a relative stability of the work machineand associated travel and/or load carrying operations, further depending in part on a travel speed, terrain characteristics, etc.

As schematically illustrated in, one example of a manually activated ride control system, or at least a portion thereof, includes cylinders,and ride control valvesin combination with an accumulator. Also represented in this example are a hydraulic tank, safety valve,, main control valve, pump, and remote control lever. This ride control systemmay be arranged to reduce or otherwise mitigate shocks by connecting the cylinders line to the accumulatorto absorb shocks when the ride control accumulator function is activated. However, this system cannot predict and fully eliminate shocks over all terrains, such that issues of material spillage remain. In addition, such a system relies on manual on/off selection using a ride control switch, and cannot be implemented using standard hardware configurations but further require the provision of extra components such as the ride control valveand the accumulator.

As schematically illustrated in, an embodiment of a predictive and automated ride control systemfor a work machineas disclosed herein includes a control systemincluding a controller. The controllermay be part of the vehicle control unit, or it may be a separate control module. The controllermay include the user interfaceand optionally be mounted in the operator cabat a control panel.

The controlleris configured to receive input signals from one or more perception sensors. The one or more perception sensorsmay generally be configured to generate signals representative of aspects of the vehicle surroundings, optionally including but not limited to ground surface conditions, incline, cross-slope, stationary and/or moving obstacles, and the like. Perception sensorsmay include imaging devices, the input signals from which may be provided directly to the controlleror for example via intervening components for analog-to-digital conversion and/or video interface (not shown).

Certain additional sensors (not shown) may be functionally linked to the controllerand provided to detect vehicle operating conditions and/or kinematics, and/or such inputs may be provided from a vehicle control system or the like.

In a particular exemplary embodiment, vehicle kinematics sensors for tracking a position of the work machine, work implement, and/or perception sensorsmay be provided in the form of inertial measurement units (each, an IMU). IMUs include a number of sensors including, but not limited to, accelerometers, which measure (among other things) velocity and acceleration, gyroscopes, which measure (among other things) angular velocity and angular acceleration, and magnetometers, which measure (among other things) strength and direction of a magnetic field. Generally, an accelerometer provides measurements, with respect to (among other things) force due to gravity, while a gyroscope provides measurements, with respect to (among other things) rigid body motion. The magnetometer provides measurements of the strength and the direction of the magnetic field, with respect to (among other things) known internal constants, or with respect to a known, accurately measured magnetic field. The magnetometer provides measurements of a magnetic field to yield information on positional, or angular, orientation of the IMU; similarly to that of the magnetometer, the gyroscope yields information on a positional, or angular, orientation of the IMU. Accordingly, the magnetometer may be used in lieu of the gyroscope, or in combination with the gyroscope, and complementary to the accelerometer, in order to produce local information and coordinates on the position, motion, and orientation of the IMU.

In another embodiment, non-kinematic sensors may be implemented for position detection, such as for example markers or other machine-readable components that are mounted or printed on the work machineand within the field of view of an imaging device as a perception sensor. In one example, April tags or an equivalent may be provided such that, depending on how the marker appears within the field of view of the imaging device, data processing elements may calculate a distance to the marker and/or orientation of the marker relative to the imaging devicefor spatially ascertaining the position of the imaging device. As another example, machine learning techniques may be implemented based on inputs for two or more known components of the work machinesuch as a front cab mount and a rear mudguard, such that the data processing units can spatially ascertain a position of the imaging device based on a distance between the two or more components and their respective positions in the field of view of the imaging device.

Other sensors functionally linked to the controllerwhich may optionally be provided for functions as described herein or otherwise may include for example load pressure sensors, global navigation satellite system (GNSS) sensors, vehicle speed sensors, ultrasonic sensors, laser scanners, radar wave transmitters and receivers, thermal sensors, imaging devices, structured light sensors, and other optical sensors, and whereas one or more of these sensors may be discrete in nature a sensor system may further refer to signals provided from a central machine control unit.

An imaging device as a perception sensormay include video cameras configured to record an original image stream and transmit corresponding data to the controller. In the alternative or in addition, exemplary perception sensorsmay include one or more of a digital (CCD/ CMOS) camera, an infrared camera, a stereoscopic camera, a PMD camera, high resolution light detection and ranging (LiDAR) scanners, radar detectors, laser scanners, and the like within the scope of the present disclosure. The number and orientation of said perception sensorsmay vary in accordance with the type of work machineand relevant applications, but may at least be provided with respect to a field of view configured to capture data associated with work machine surroundings and associated objects proximate thereto.

One of skill in the art may appreciate that image data processing functions may be performed discretely at a given imaging device if properly configured, but most if not all image data processing may generally be performed by the controlleror other downstream data processor. For example, image data or the equivalent from any one or more perception sensorsmay be provided for three-dimensional point cloud generation, image segmentation, object delineation and classification, and the like, using data processing tools as are known in the art in combination with the objectives disclosed.

The controllerof the work machinemay be configured to produce outputs, as further described below, to a user interfaceassociated with a display unitfor display to the human operator. The controllermay be configured to receive inputs from the user interface, such as user input provided via the user interface. Not specifically represented in, the controllerof the work machinemay in some embodiments further receive inputs from and generate outputs to remote devices associated with a user via a respective user interface, for example a display unit with touchscreen interface. Data transmission between for example the vehicle control system and a remote user interface may take the form of a wireless communications system and associated components as are conventionally known in the art.

In an embodiment, a remote serversuch as in the form of a cloud server environment may include one or more processorsfunctionally linked with data storage. The remote servermay include models as further described below in the data storage. In certain embodiments, a remote user interface and vehicle control systems for respective work machines may be further coordinated or otherwise interact with the remote serveror other computing device for the performance of operations in a system as disclosed herein.

The controllermay be configured to generate control signals for controlling the operation of respective actuators, or signals for indirect control via intermediate control units, associated with a machine steering control system, a machine implement control system, and/or a machine drive control system. The controllermay for example be electrically coupled to respective components of these and/or other systems by a wiring harness such that messages, commands, and electrical power may be transmitted between the controller  and the remainder of the work machine. The controllermay be coupled to other controllers, such as for example the engine control unit (ECU), through a controller area network (CAN) bus, and may then send and receive messages over the CAN bus to communicate with other components thereof.

For example, control signals may comprise a steering control signal or data message that defines a steering angle of the steering shaft, a braking control signal or data message that defines the amount of deceleration, hydraulic pressure, or braking friction to the applied to brakes, a propulsion control signal or data message that controls a throttle setting, a fuel flow, a fuel injection system, vehicular speed, or vehicular acceleration. Further, where the work machinemay be propelled by an electric drive or electric motor, the propulsion control signal may control or modulate electrical energy, electrical current, electrical voltage provided to an electric drive or motor. The control signals generally vary with time as necessary to track the path plan. The lines that interconnect the components of the system may comprise logical communication paths, physical communication paths, or both. Logical communication paths may comprise communications or links between software modules, instructions, or data, whereas physical communication paths may comprise transmission lines, data buses, or communication channels, to name non-limiting examples.

The steering control unitmay for example comprise or otherwise interact with an electrically controlled hydraulic steering system, an electrically driven rack and pinion steering, an Ackerman steering system, or another steering system. The drive control unitmay for example comprise or otherwise interact with an internal combustion engine, an internal combustion engine-electric hybrid system, an electric drive system, or the like.

The controllermay include or be associated with one or more processors, computer readable media, a communication unit, data storagesuch as for example a database network, and the aforementioned user interfaceor control panelhaving a display. An input/output device, such as a keyboard, joystick or other user interface tool, is provided so that the human operator may input instructions to the controller. It is understood that the controller described herein may be a single controller having all of the described functionality, or it may include multiple controllers wherein the described functionality is distributed among the multiple controllers.

Various operations, steps or algorithms as described in connection with the controllercan be embodied directly in hardware, in a computer program product such as a software module executed by the processor, or in a combination of the two. The computer program product can reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, or any other form of computer-readable mediumknown in the art. An exemplary computer-readable medium can be coupled to the processor such that the processor can read information from, and write information to, the memory/ storage medium. In the alternative, the medium can be integral to the processor. The processor and the medium can reside in an application specific integrated circuit (ASIC). The ASIC can reside in a user terminal. In the alternative, the processor and the medium can reside as discrete components in a user terminal.

The term “processor”as used herein may refer to at least general-purpose or specific-purpose processing devices and/or logic as may be understood by one of skill in the art, including but not limited to a microprocessor, a microcontroller, a state machine, and the like. A processor can also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.