Patent ID: 12209384

DETAILED DESCRIPTION

FIG.1depicts a representative self-propelled work machine20in the form of, for example, a tracked excavator machine. The work machine20includes an undercarriage22including first and second ground engaging units24including first and second travel motors (not shown) for driving the first and second ground engaging units24, respectively. A main frame32is supported from the undercarriage22by a swing bearing34such that the main frame32is pivotable about a pivot axis36relative to the undercarriage22. The pivot axis36is substantially vertical when a ground surface38engaged by the ground engaging units24is substantially horizontal. A swing motor (not shown) is configured to pivot the main frame32on the swing bearing34about the pivot axis36relative to the undercarriage22.

In an embodiment, a swing angle sensor (not shown) may include an upper sensor part mounted on the main frame32and a lower sensor part mounted on the undercarriage22. Such a swing angle sensor may be configured to provide a swing (or pivot) angle signal corresponding to a pivot position of the main frame32relative to the undercarriage22about the pivot axis36. The swing angle sensor may for example be a Hall Effect rotational sensor including a Hall element, a rotating shaft, and a magnet, wherein as the angular position of the Hall element changes, the corresponding changes in the magnetic field result in a linear change in output voltage. Other suitable types of rotary position sensors include rotary potentiometers, resolvers, optical encoders, inductive sensors, and the like.

A work implement42in the context of the referenced work machine20is a boom assembly having numerous components in the form of a boom44pivotably connected to the main frame32at a linkage joint105, an arm46pivotally connected to the boom44at a linkage joint106, and a working tool48. The boom44is pivotally attached to the main frame32to pivot about a generally horizontal axis relative to the main frame32. The working tool48in this embodiment is an excavator shovel, which is pivotally connected to the arm46at a linkage joint110. One end of a dogbone47is pivotally connected to the arm46at a linkage joint, and another end of the dogbone47is pivotally connected to a tool link49. A tool link49in the context of the referenced work machine20is a bucket link49.

The boom assembly42extends from the main frame32along a working direction of the boom assembly42. The working direction can also be described as a working direction of the boom44. As described herein, control of the work implement42may relate to control of any one or more of the associated components (e.g., boom44, arm46, tool48).

Referring again to the embodiment ofFIG.1, the first and second ground engaging units24are tracked ground engaging units but in various embodiments may be wheels. Each of the tracked ground engaging units24includes a front idler52, a drive sprocket54, and a track chain56extending around the front idler52and the drive sprocket54. The travel motor of each tracked ground engaging unit24drives its respective drive sprocket54. Each tracked ground engaging unit24has a forward traveling direction58defined from the drive sprocket54toward the front idler52. The forward traveling direction58of the tracked ground engaging units24also defines a forward traveling direction58of the undercarriage22and thus of the working machine20.

An operator's cab60may be located on the main frame32. The operator's cab60and the boom assembly42may both be mounted on the main frame32so that the operator's cab60faces in the working direction58of the boom assembly. A control station62may be located in the operator's cab60.

Also mounted on the main frame32is an engine64for powering the working machine20. The engine64may be a diesel internal combustion engine. The engine64may drive a hydraulic pump to provide hydraulic power to the various operating systems of the working machine20.

As schematically illustrated inFIG.3, the work machine20may include a control system including a controller112. The controller may be part of the machine control system of the working machine, or it may be a separate control module. The controller112may include a user interface114and optionally be mounted in the operator's cab60at the control station62.

The controller112is configured to receive input signals from some or all of various sensors102,104,108as further described below. Various sensors102,104,108may typically be discrete in nature, but signals representative of more than one input parameter may be provided from the same sensor, and a sensor system102,104,108as disclosed herein may further include or otherwise refer to signals provided from the machine control system.

In an embodiment a set of inertial navigation system (INS) sensors104may be mounted on the work machine20, as represented generally including multiple sensors104a,104b,104c,104d,104erespectively mounted to the main frame32, the boom44, the arm46, the dogbone47, and the tool48.

In the embodiment represented inFIG.1, which is intended as illustrative and non-limiting unless otherwise specifically noted herein, a sensor system104may include a sensor104amounted on the main frame32; a sensor104bmounted on the boom44; a sensor104cmounted on the arm46; a sensor104dmounted on the dogbone47; and a sensor104emounted on the tool48. Respective sensors may for example be mounted on opposing sides of at least one linkage joint. An opposing side of the at least one linkage joint may be ascertained by mounting or affixation of the sensor system104on either side of the at least one linkage joint, which is defined as a pivotal linkage joint connecting the one or more components of the work implement42.

For example, the at least one linkage joint may be defined at a linkage joint106, which constitutes a pivotal connection of the boom44and the arm46. In this example, the sensor system104may be mounted in such a manner that the opposing sides of the at least one linkage joint are defined as follows: the sensor104bmounted on the boom44opposing the sensor104cmounted on the arm46; the sensor104bmounted on the boom44opposing the sensor104dmounted on the dogbone47; or the sensor104bmounted on the boom44opposing the sensor104emounted on the tool48.

As a further example, the at least one linkage joint may be defined at a pivotal connection of the arm46to the dogbone47. In this example, the sensor system104may be mounted in such a manner that the opposing sides of the at least one linkage joint are defined as follows: the sensor104cmounted on the arm46opposing the sensor104dmounted on the dogbone47; the sensor104cmounted on the arm46opposing the sensor104emounted on the tool48; the sensor104bmounted on the boom44opposing the sensor104dmounted on the dogbone47; or the sensor104bmounted on the boom44opposing the sensor104emounted on the tool48.

As a further example, the at least one linkage joint may be defined at a linkage joint110, which constitutes a pivotal connection between the arm46and the tool48. In this example, the sensor system104may be mounted in such a manner that the opposing sides of the at least one linkage joint are defined as follows: the sensor104dmounted on the dogbone47opposing the sensor104emounted on the tool48; the sensor104cmounted on the arm46opposing the sensor104emounted on the tool48; or the sensor104bmounted on the boom44opposing the sensor104emounted on the tool48.

The sensor system104may be oriented in an x-, y-, and z-axis coordinate system. Using as one example the sensor104cas mounted on the arm46and the sensor104das mounted on the dogbone47, respective body frames of the sensors104cand104d(not shown) may be mounted such that the x-axes of the aforementioned body frames point along the direction of the work implement42. Alternatively, the body frame of the sensor104cand the body frame of the sensor104dmay be mounted in a manner such that the z-axes of the aforementioned body frames point in the direction of the main frame32of the work machine20(i.e., the excavator). Because an x-, y-, and z-axis coordinate system may be defined arbitrarily, the foregoing are not intended as limiting. The x-, y-, and z-axis coordinate system, though it may be defined arbitrarily, relates to the mechanical axes of rotation for roll (i.e., rotation about the x-axis), pitch (i.e., rotation about the y-axis), and yaw (i.e., rotation about the z-axis).

Some or all of the sensors104in the context of the referenced work machine20may include inertial measurement units (each, an IMU). IMUS are tools that capture a variety of motion- and position-based measurements, including, but not limited to, velocity, acceleration, angular velocity, and angular acceleration.

IMUs may 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.

As conventionally known in the art, an accelerometer is an electro-mechanical device or tool used to measure acceleration (m/s2), which is defined as the rate of change of velocity (m/s) of an object. Accelerometers sense either static forces (e.g., gravity) or dynamic forces of acceleration (e.g., vibration and movement). An accelerometer may receive sense elements measuring the force due to gravity. By measuring the quantity of static acceleration due to gravity of the Earth, an accelerometer may provide data as to the angle the object is tilted with respect to the Earth, the angle of which may be established in an x-, y-, and z-axis coordinate frame. However, where the object is accelerating in a particular direction, such that the acceleration is dynamic (as opposed to static), the accelerometer produces data which does not effectively distinguish the dynamic forces of motion from the force due to gravity by the Earth. Also as conventionally known in the art, a gyroscope is a device used to measure changes in orientation, based upon the object's angular velocity (rad/s) or angular acceleration (rad/s2). A gyroscope may constitute a mechanical gyroscope, a micro-electro-mechanical system (MEMS) gyroscope, a ring laser gyroscope, a fiber-optic gyroscope, and/or other gyroscopes as are known in the art. Principally, a gyroscope is employed to measure changes in angular position of an object in motion, the angular position of which may be established in an x-, y-, and z-axis coordinate frame.

In an embodiment, for each of at least one linkage joint as referenced above, sense elements from the received sensor output signals may be fused in an independent coordinate frame associated at least in part with the respective linkage joint, the independent coordinate frame of which is independent of a global navigation frame for the work machine20, wherein for example measurements received by sensor system104may be merged to produce a desired output in the work implement42of the work machine20.

One or more laser receivers102as are conventionally known in the art may further be mounted on the work machine20for catching a laser reference72as represented inFIG.2. The laser reference72may be generated from a laser source70remotely positioned and in a stationary manner with respect to the work machine20. A plane of the laser reference72may include a slope, direction, and height or predetermined/defined elevation offset78with respect to a target surface profile76, the target surface profile76further corresponding to an amount of material to be graded away from an initial or current surface profile74.

The controller112may be configured to produce outputs, as further described below, to a user interface114for display to the human operator or other appropriate user. The controller112may be configured to receive inputs from the user interface114, such as user input provided via the user interface114. Not specifically represented inFIG.3, the controller112of the work machine20may 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 a 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 certain embodiments, a remote user interface and vehicle control systems for respective work machines20may be further coordinated or otherwise interact with a remote server or other computing device for the performance of operations in a system as disclosed herein.

The controller112may further, or in the alternative, 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 system126, a machine implement control system128, and/or an engine speed control system130. The control systems126,128,130may be independent or otherwise integrated together or as part of a machine control unit in various manners as known in the art. The controller112may, for example, generate control signals for controlling the operation of various actuators, such as hydraulic motors or hydraulic piston-cylinder units41,43,45, and electronic control signals from the controller112may actually be received by electro-hydraulic control valves associated with the actuators such that the electro-hydraulic control valves will control the flow of hydraulic fluid to and from the respective hydraulic actuators to control the actuation thereof in response to the control signal from the controller112. In an embodiment, the controller112may in the context of a control operation further receive a pivot angle signal from a pivot angle sensor as described above and selectively drive a swing motor automatically to rotate the main frame32about the pivot axis36relative to the undercarriage22to a target pivot position of the main frame32relative to the undercarriage22, as part of an aforementioned control unit126,128,130or optionally as a separate and/or integrated control unit within the scope of the present disclosure.

The controller112may include, or be associated with, a processor150, a computer readable medium152, a communication unit154, data storage156such as for example a database network, and the aforementioned user interface114or control panel having a display118. An input/output device, such as a keyboard, joystick or other user interface tool116, is provided so that the human operator may input instructions to the controller112. It is understood that the controller112described 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 “computer-implemented” operations, steps or algorithms as described in connection with the controller112or alternative but equivalent computing devices or systems can be embodied directly in hardware, in a computer program product such as a software module executed by the processor150, 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 medium152known in the art. An exemplary computer-readable medium152can be coupled to the processor150such that the processor150can read information from, and write information to, the memory/storage medium152. In the alternative, the medium152can be integral to the processor150. The processor150and the medium152can reside in an application specific integrated circuit (ASIC). The ASIC can reside in a user terminal. In the alternative, the processor150and the medium152can reside as discrete components in a user terminal.

The term “processor”150as 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 processor150can also be implemented as a combination of computing devices, e.g., a combination of a digital signal processor (DSP) and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

The communication unit154may support or provide communications between the controller112and external systems or devices, and/or support or provide communication interface with respect to internal components of the self-propelled work machine20. The communications unit154may include wireless communication system components (e.g., via cellular modem, WiFi, Bluetooth, or the like) and/or may include one or more wired communications terminals such as universal serial bus ports.

The data storage156as further described below may, unless otherwise stated, generally encompass hardware such as volatile or non-volatile storage devices, drives, memory, or other storage media, as well as one or more databases residing thereon.

InFIG.4, the depicted flowchart represents an exemplary embodiment of a method for controlling movements (e.g., associated with grading operations) of one or more work implements42for a work machine20, the work implement42of which includes one or more components coupled to a main frame32of the work machine20. In the context of the exemplary work implement42of the work machine20depicted inFIG.1, the one or more components may include a boom44, an arm46, and a tool48.

The exemplary method may be described herein with respect to three exemplary embodiments, generally corresponding to a work machine20lacking an inertial navigation system (beginning with step410), a work machine20including an inertial navigation system (beginning with step420), and a work machine20further including a visual-inertial navigation system (beginning with step430). It may be understood that the represented embodiments are non-limiting in nature and that various alternatives may be within the scope of the present disclosure and contemplated by one of skill in the art upon examination of the teachings herein.

Beginning for illustrative purposes with step420, if a two-dimensional grading system includes a set of sensors104including for example a swing angle sensor, it has the ability to calculate an orientation of the ground engaging units24of the work machine20relative to the plane of the laser reference72by capturing the laser transmitted by the laser source70at each of a plurality of locations which may correspond to different swing angles. In practice, the system may utilize inertial navigation to calculate how the ground engaging units24have moved (step422) and based thereon to predict when the laser reference72plane will be sensed (step436), based for example on previously stored navigation settings. The system then monitors signals from the laser receiver102for receipt of the laser reference72(step438).

If the laser plane is either not sensed when expected, or is sensed when it is not expected to be sensed, the system may be configured to accordingly identify that there has been a tracking error in the INS (i.e., “yes” in response to the query in step440). It may for example use the actual measurement of the plane of the laser reference72to attempt to automatically correct for this tracking error via a tracking correction routine (step460). As one alternative, the system may prompt the operator via an onboard user interface or the like to capture the laser plane at several other swing angles in order to calculate the slope of the laser plane relative to the machine. If the work machine20is moved so that it captures the laser plane in a plurality of positions (e.g., three positions, including at least two substantially different swing angles), it can resolve the orientation of the laser plane with respect to the new track location.

In an embodiment, two or more of the positions in the tracking correction routine may be predetermined, wherein the system automatically directs the implement through a sequence of swing angles, or the operator may be prompted to direct the implement accordingly. For example, a preferred routine may include that at least two of the swing angles are implemented at least a predetermined distance apart from each other. Such positions and/or swing angles may be presented in accordance with a stored and fixed setting, or may be dynamic in nature such that for example the preferred tracking routine may be determined in view of current conditions and/or learned correlations over time.

As the swing angles of the tracking correction routine are implemented, the system can then use the signals from the swing angle sensor in combination with the received laser reference72signals to resolve the current slope of the plane in an independent coordinate system of the work machine20regardless of how the main frame32(or upper) rotates with respect to the tracks. In this way, the work machine may preferably maintain the proper slope regardless of the track orientation relative to the laser plane.

If no tracking error is determined (i.e., “no” in response to the query in step440), or upon satisfactory completion of the tracking correction routine in step460, the system determines the orientation and current slope of the laser reference72plane in the work machine coordinate system (step470). For example, as the work machine20rotates with the laser receiver102in the effective plane of the laser reference72, a cloud of three-dimensional points may be collected along the corresponding arc. These points may be measured or otherwise converted with respect to the coordinate system of the work machine20, wherein upon best-fitting (or equivalent) a plane to these three-dimensional points the slope, direction, and height of the laser plane can be found in work machine coordinates. When this information is combined with an offset height value78associated with the laser reference72, the system can determine the target surface profile76(step480).

In an embodiment, the target surface profile is accordingly determined in a work machine coordinate system based on the determined plane of the laser reference and the defined elevation offset, and as further described below movement of one or more components of the work implement42is controlled with respect to the determined target surface profile76. In another embodiment within the scope of the present disclosure, a position of the work machine20in a target surface coordinate system may be determined based on the determined plane of the laser reference and the defined elevation offset, wherein movement of one or more components of the work implement42is controlled with respect to the determined target surface profile76.

The grade control system may then (in step490) direct control of a grading operation in accordance with the determined target surface profile76, wherein for example movement of the work machine20and/or one or more work implement components is controlled or directed based at least in part on the determined target surface profile76and further in view of tracked positions of the work implement42. The tracked positions may include at least one joint characteristic, such as a joint angle, for a respective linkage joint. The controller112may be configured to automatically control movement of the one or more work implements of the boom assembly42of the work machine20, via one or more of a steering control unit126, a swing angle or equivalent implement control unit128, and an engine speed control unit130. The human operator may effectuate movement or direction of the ground engaging units24and/or one or more work implements by or through the user interface tool116of the user interface114. The controller112may, for example, generate control signals for controlling the operation of various actuators, such as hydraulic motors or hydraulic piston-cylinder units41,43, and45, as depicted inFIG.1.

In some embodiments, a display may be generated including a determined target surface profile76or characteristics thereof, as further optionally supplemented by the tracked laser reference72, the initial or current surface profile74as corresponding for example to unworked terrain, and/or joint characteristics, such as joint angles, for respective linkage joints of the boom assembly42.

In an embodiment wherein the work machine20lacks an INS (beginning with step410), the system may for example detect an advance of the work machine (step412) but be unable to detect movements of the ground engaging units24relative to the machine frame32or work implement(s)42in the same manner as a work machine equipped with an INS. In this case, the system may prompt the operator to direct movements of the work machine and accordingly the laser receiver102so as to catch the laser plane in a plurality of (e.g., three) positions each time the ground engaging units24are advanced (step414). This step enables receipt of the laser reference72and determination of tracking errors in similar fashion as with respect to the embodiment beginning with step420, even though the work machine lacking the INS sensors likewise lacks the ability to predict when the laser receiver102will be positioned to catch the laser reference72.

In another embodiment (beginning with step430) the work machine20may further include a visual-inertial navigation system (VINS) configured to sense, classify, and track stationary features/static elements around the work machine (step432). The system may then reference these visual markers to the slope of the laser plane. As the ground engaging units24are moved, the controller112or an equivalent may use the visual markers and/or inertial data to calculate work machine motion and track the orientation and location of the laser plane relative to work machine coordinates (step434). The system may then predict the location and slope of the laser plane relative to the new location of the tracks after motion (step436). In an embodiment, when the laser plane is actually detected (step438), if the error is relatively small (for example by reference to a threshold amount or otherwise outside of a defined range) it may be used for example to correct the VINS system for small tracking errors. If the error was large, the system may be configured to alert the operator to reinitialize the tracking of the laser plane. The operator may for example be prompted by the system to catch the plane in a plurality (e.g., three) different machine poses, wherein tracking and grade control operations may resume as before.

An exemplary VINS may include INS sensors104as discussed previously and further in functional association with one or more sensors108and communications and/or computing modules effective to process image data or the like there from. VINS sensors108may include for example video cameras configured to record an original image stream and transmit corresponding data to the controller112. In the alternative or in addition, the VINS sensors108may include one or more of an infrared camera, a stereoscopic camera, a PMD camera, or the like. One of skill in the art may appreciate that high resolution light detection and ranging (LiDAR) scanners, radar detectors, laser scanners, etc. may likewise be implemented within the scope of the present disclosure. The number and orientation of said sensors108may vary in accordance with the type of work machine20and relevant applications. For example, the position and size of an image region recorded by a respective camera as a VINS sensor108may depend on the arrangement and orientation of the camera and the camera lens system, in particular the focal length of the lens of the camera. One of skill in the art may further appreciate that image data processing functions may be performed discretely at a given image data source if properly configured, but also or otherwise may generally include at least some image data processing by the controller or other downstream data processor. For example, image data from any one or more image data sources may be provided for three-dimensional point cloud generation, image segmentation, object delineation and classification, and the like, using image data processing tools as are known in the art in combination with the objectives disclosed.

Various sensors108may collectively define an object detection system, alone or in combination with one or more aforementioned sensors for improved data collection, various examples of which may include ultrasonic sensors, laser scanners, radar wave transmitters and receivers, thermal sensors, imaging devices, structured light sensors, other optical sensors, and the like. The types and combinations of sensors for object detection may vary for a type of work machine20, work area, and/or application, but generally may be provided and configured to optimize recognition of objects proximate to, or otherwise in association with, a determined working area of the work machine.

In various embodiments as disclosed herein, a plurality of operating modes may be enabled with respect to automated or alert/notification functions. The operating modes may typically be selectable manually according to user input (step450), but in other embodiments may for example be automatically selected by the system in the absence of a manual selection. In certain exemplary user-selected operating modes, the system may automatically attempt to determine the plane of the laser reference72responsive to any movement of the laser receiver102, and generate output signals to an onboard user interface114based on a state of the determined plane of the laser reference72and/or the determined target surface profile76. For example, an alert may be generated if there is ambiguity regarding the orientation of the laser plane with respect to the work machine coordinates (step454), and/or if a substantial misalignment has been detected (step456). In another user-selected operating mode (step452), the laser reference72may be automatically monitored for receipt at a plurality of positions for determining a plane of the laser reference72without generating an output signal to alert an operator.

As used herein, the phrase “one or more of,” when used with a list of items, means that different combinations of one or more of the items may be used and only one of each item in the list may be needed. For example, “one or more of” item A, item B, and item C may include, for example, without limitation, item A or item A and item B. This example also may include item A, item B, and item C, or item Band item C.

Thus, it is seen that the apparatus and methods of the present disclosure readily achieve the ends and advantages mentioned as well as those inherent therein. While certain preferred embodiments of the disclosure have been illustrated and described for present purposes, numerous changes in the arrangement and construction of parts and steps may be made by those skilled in the art, which changes are encompassed within the scope and spirit of the present disclosure as defined by the appended claims. Each disclosed feature or embodiment may be combined with any of the other disclosed features or embodiments.