Hydrostatic Swivel Actuation, Monitoring, and Control System

Abstract

A swing motion control system for an earthmoving machine (10) may include a closed-loop hydraulic circuit including a hydrostatic swing pump (686) fluidly coupled to at least one hydraulic swing motor (682, 684) configured to control a swing mechanism of the earthmoving machine (10), a pressure controller (664) configured to control the pressure of fluid supplied to the hydrostatic swing pump (686) to control the pressure output by the pump (686), and a controller (700). The controller (700) may be configured to monitor and process signals received from sensors and operator inputs, the signals received from the sensors being indicative of the machine's position and attitude and the inertial mass of the swing components and payload moved by the swing mechanism of the machine (10), and to control at least one of an offset to a desired pump displacement by the hydrostatic swing pump (686) or an offset to a pump output pressure from the hydrostatic swing pump (686) based on at least one of the amount of tilt at which the machine (10) is operating or the inertial mass of the swing components and payload.

Description

[Technical field]

[0001] The present disclosure relates generally to a swing motion actuation and control system for maintaining a swing mechanism of a machine stationary, and more particularly to a swing motion actuation and control system of a machine including a hydrostatic pump that supplies fluid to a motor in a closed loop hydraulic circuit to selectively maintain the swing mechanism stationary. [Background technology]

[0002] For example, machines such as bulldozers, motor graders, wheel loaders, wheel tractor scrapers, and other types of heavy equipment are used to perform a variety of tasks. Effective control of the machines requires accurate and responsive readings from sensors to perform calculations that provide information to the machine control or human operators in near real-time. Autonomously and semi-autonomously controlled machines can operate with little or no human input by relying on information received from various machine systems. For example, the machines can be controlled to complete programmed tasks remotely and / or automatically based on machine movement inputs, terrain inputs, and / or machine operation inputs. By receiving appropriate feedback from each of the different machine systems and sensors during task execution, machine operation can be continually adjusted to help ensure accuracy and safety in task completion. However, to do this, the information provided by the different machine systems and sensors must be accurate and reliable. The position, speed, and distance as the machine moves, as well as the position, motion, and orientation of the different parts or components of the machine, are parameters whose accuracy can be important to the control of the machine and its operation. In machines such as mining machines that include swing components such as a boom, stick, and implement or work tool, an open-loop swing system is provided that can control the swing motion of the components from a mining or loading position to a discharge position, or from a discharge position back to the mining or loading position. When the machine is on a slope, the components such as, for example, the boom, stick, and implement may drift from an operator-commanded position as a result of the effect of gravity on the components. Conventional solutions to this drift problem may include attempting to use low-leakage hydraulic control valves to hydraulically lock the swing components to prevent them from drifting when the machine is on a slope.

[0003] Conventional machines typically utilize navigation or positioning systems to determine various operational parameters such as the machine's position, speed, pitch rate, yaw rate, and roll rate. The machine's position and orientation is referred to as the machine's "attitude." The machine's "state" includes the machine's attitude, as well as various additional operational parameters that can be used to model the machine's kinematics and dynamics, such as parameters that characterize the machine's various links, joints, tools, hydraulics, and power systems. Some conventional machines determine these parameters using one or more combinations of Global Navigation Satellite System (GNSS) data, Distance Measurement Indicator (DMI) or odometer measurement data, Inertial Measurement Unit (IMU) data, and the like. Some machines utilize RADAR sensors, SONAR sensors, LIDAR sensors, IR and non-IR cameras, and other similar sensors to help guide the machine safely and efficiently along different types of terrain. Conventional machines have attempted to fuse these different types of data to determine the position of the land vehicle.

[0004] An exemplary system that may be utilized to determine the location of a machine is disclosed in U.S. Patent Application Publication No. 2008 / 0033645 to Levinson et al., published February 7, 2008 ("the '645 Publication"). The system of the '645 Publication utilizes location information data from sensors such as a Global Positioning System (GPS), as well as scene data from a LIDAR (Light Detection and Ranging) device to determine the location of the machine. Specifically, the data is used to create a high resolution map of the terrain, and the machine's location is confined and identified on the map.

[0005] While the '645 system may be useful for determining the overall position of a machine, it may not provide accurate estimates for the machine's position or machine components during inference (i.e., periods when a GPS signal is not available). Additionally, because the '645 system does not check the accuracy of the GPS signal, the '645 system may not provide accurate position information if the GPS signal is unreliable or erroneous due to multipath errors, position jumps, etc. Finally, the '645 system does not provide a means for monitoring and controllably maintaining the position of the machine's rotating components when the machine is operating on an incline.

[0006] The systems and methods of the present disclosure include the use of a dedicated hydrostatic pump to supply fluid to a hydraulic motor in a closed loop system to provide an accurate determination of the position of the machine and machine components as well as to maintain the position of the machine's swing components relative to the machine's undercarriage when the machine is operating on an incline. A swing motion control system for an earthmoving machine, according to various exemplary embodiments of the present disclosure, may include a closed loop swing motion control system including a hydrostatic swing pump fluidly coupled to at least one hydraulic swing motor configured to control a swing mechanism of the earthmoving machine. Summary of the Invention

[0007] In one aspect, the present disclosure is directed to a closed loop swing motion control system for an earth moving machine. The swing motion control system may include a closed loop hydraulic circuit including a hydrostatic swing pump fluidly coupled to at least one hydraulic swing motor configured to control a swing mechanism of the earth moving machine, and a pressure controller configured to control a pressure of fluid supplied to the hydrostatic swing pump to control a pressure output by the pump. The swing motion control system may include a controller configured to monitor and process signals received from sensors and operator inputs. The signals received from the sensors may be indicative of the position and attitude of the machine and the inertial mass of the swing components and payload moved by the swing mechanism of the machine. The controller may also be configured to control at least one of an offset amount to a desired pump displacement by the hydrostatic swing pump or an offset amount to a pump output pressure from the hydrostatic swing pump based on at least one of an amount of tilt at which the machine is operating or the inertial mass of the swing components and payload.

[0008] In another aspect, the present disclosure is directed to an earth moving machine including a closed loop swing motion control system. The swing motion control system may include a closed loop hydraulic circuit including a hydrostatic swing pump fluidly coupled to at least one hydraulic swing motor configured to control a swing mechanism of the earth moving machine, and a pressure controller configured to control a pressure of a fluid supplied to the hydrostatic swing pump to control a pressure output by the pump. The swing motion control system may include a controller configured to monitor and process signals received from sensors and operator inputs. The signals received from the sensors may be indicative of the position and attitude of the machine and the inertial mass of the swing components and payload moved by the swing mechanism of the machine. The controller may also be configured to control at least one of an offset amount to a desired pump displacement by the hydrostatic swing pump or an offset amount to a pump output pressure from the hydrostatic swing pump based on at least one of an amount of tilt at which the machine is operating or the inertial mass of the swing components and payload.

[0009] In yet another aspect, the present disclosure is directed to an earth moving machine including a plurality of sensors configured to generate signals indicative of the position and attitude of the machine and the inertial mass of a swing component and a payload configured to be moved by a swing mechanism of the machine, and a closed loop swing motion control system. The swing motion control system may include a closed loop hydraulic circuit including a hydrostatic swing pump fluidly coupled to at least one hydraulic swing motor configured to control a swing mechanism of the earth moving machine, and a pressure controller configured to control a pressure of fluid supplied to the hydrostatic swing pump to control a pressure output by the pump. The swing motion control system may include a controller configured to monitor and process signals received from the sensors and operator input. The controller may also be configured to control at least one of an offset amount to a desired pump displacement by the hydrostatic swing pump or an offset amount to a pump output pressure from the hydrostatic swing pump based on at least one of an amount of tilt at which the machine is operating or an inertial mass of the swing component and a payload. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a pictorial diagram of an example disclosed machine that may be operated using systems and methods for determining real-time machine conditions according to an exemplary embodiment of the present disclosure. [Diagram 2] FIG. 2 is a schematic diagram of an exemplary disclosed sensor fusion system for determining the state of the machine of FIG. [Diagram 3] 3 is a schematic diagram of an example application of output from the sensor fusion system of FIG. 2 to provide real-time information used to control the operation and attitude of the example disclosed machine of FIG. 1. [Figure 4] FIG. 4 is a schematic diagram of an example application of output from the sensor fusion system of FIG. 2 to provide enhanced hydraulic output during selected operations of the example disclosed machine of FIG. [Diagram 5]FIG. 5 is a schematic diagram of an example implementation of the sensor fusion system of FIG. [Figure 6] FIG. 6 is a schematic diagram of a closed loop hydrostatic system according to an exemplary embodiment of the present disclosure. [Figure 7] FIG. 7 is a schematic diagram of a swing motion actuation and control system used in conjunction with the closed loop hydrostatic system of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] FIG. 1 illustrates a machine 10 including multiple inertial measurement units (IMUs) 24, 25, 26, and 27 applied to different locations on components or portions of the machine 10, such as machine body 14, boom 17, stick 18, and bucket (or other tool) 19. In a machine state control system according to various exemplary embodiments of the present disclosure, the IMUs attached to different components and / or portions of the machine 10 may replace or complement conventional sensors such as pitch and roll sensor 32, cylinder position sensor 34, and rotational position sensor 36. Each IMU may include one or more accelerometers, one or more gyroscopes, and possibly a magnetometer to provide a signal indicative of an orientation relative to the magnetic poles of the earth. The accelerometers and gyroscopes of each IMU provide signals usable to identify the position and orientation of the IMU, and thus the machine component to which the IMU is attached, relative to a body frame of reference. IMUs may provide a lower cost, more reliable alternative to conventional sensors such as position sensing cylinders and rotational position sensors, and are easily retrofittable to existing machines by simply welding the IMU to different exterior parts of the machine without requiring disassembly of the machine or machine components. Machine electronic control modules (ECMs) configured to send control signals to various systems and subsystems of the machine may be reprogrammed and configured to receive signals from the retrofitted IMU, which are processed and converted into real-time inputs used by the ECM to modify the control signals based on the inputs.

[0012] Various non-IMU sensors 230 (see FIG. 2) may be added or removed depending on the particular machine application and configuration. The non-IMU sensors may include various perception sensors included as part of the vision system, as well as position and / or speed sensors, such as the superstructure position / speed sensor 22, the laser catcher sensor 28 configured to provide a signal indicative of a position measured by a laser, cylinder position sensors 34, hydraulic system sensors, electrical system sensors, braking system sensors, fuel system sensors, and other sensors that provide real-time input to the ECM for use in monitoring the status of and controlling the operation of the machine's systems and subsystems.

[0013] In various exemplary embodiments according to the present disclosure, a swing operation actuation and control system 700 may monitor and responsively controllably maintain the position of a swing mechanism, including swing components such as boom 17, stick 18 and work tool 19, relative to the undercarriage of a machine 10, such as the excavator shown in Figure 1. When a machine having swing components, such as the machine (excavator) 10 of Figure 1, is operating on a slope or rough terrain, the swing components, such as boom 17, stick 18 and tool 19, may drift away from the speed and / or position commanded by the machine operator.

[0014] 6 and 7, a swing motion actuation and control system 700 according to various exemplary embodiments of the present disclosure may operate in conjunction with a closed hydrostatic loop 660 fluidly connecting an independent, dedicated hydrostatic swing pump 686 to one or more hydraulic motors 682, 684 operably connected to the rotating frame and machine body 14 of the machine 10 to control the swing motion of the boom 17, stick 18 and tool 19 relative to the undercarriage or body of the machine 10. The closed hydrostatic loop 660 may also include a source of pilot supply pressure 662 fluidly connected through a pressure control device, such as a supply pressure override valve 664, to generate a reduced pressure pilot supply pressure 672 that is supplied to a pump regulator associated with the hydrostatic swing pump 686. Additionally or alternatively, the closed hydrostatic loop 660 may include a pressure control device in the form of a closed loop control that adjusts pump displacement based on total system pressure. The hydrostatic loop pressure sensors 692 , 694 may be configured to generate signals indicative of the resultant hydraulic fluid pressure on opposite sides of the hydrostatic slew pump 686 .

[0015] A separate independent braking system, such as a hydraulic brake or parking brake, may also be operatively coupled to the swing mechanism to help maintain the swing mechanism stationary or otherwise prevent uncommanded rotation or movement of the swing mechanism. An ECM configured to send control signals to the various systems and subsystems of the machine, or an entirely separate dedicated swing controller, via control logic, may be configured to receive and process signals from the IMU and various non-IMU sensors located on the machine 10 to determine roll, angle, tilt, and other information indicative of the position and orientation of the machine 10 and the relative position and orientation of the swing components with respect to the undercarriage or body of the machine 10. The controller may also be configured to receive and process signals indicative of expected inertia of the forward linkages, such as the boom 17, stick 18, and tool 19, with or without a payload. These signals indicative of expected inertia may include, for example, sensor-generated signals indicative of boom head end pressure in coordination with, based on, and / or as a function of the roll angle, tilt, and position orientation of the machine 10.

[0016] When rotation or movement of a swing mechanism, such as boom 17, stick 18, and tools 19 on excavator 10, is commanded by a machine operator, swing operation actuation and control system 700 may be configured to engage and actuate the swing mechanism while simultaneously, controllably, responsively, and progressively actuating the release of the brake system. Control of the swing mechanism in conjunction with control of the brake system may be based on the aforementioned position and inertial information to prevent unintended and / or uncommanded acceleration, swing, or movement, particularly when machine 10 is operating on sloped or uneven surfaces.

[0017] In various alternative configurations, the machine 10 may be configured to perform any type of operation associated with an industry, such as mining, construction, agriculture, transportation, power generation, or any other industry known in the art. For example, the machine 10 may be an earth moving machine, such as a haul truck, bulldozer, loader, backhoe, excavator, motor grader, wheeled tractor scraper, or any other earth moving machine. The machine 10 may generally include a track assembly or other traction device 12 (i.e., ground engaging device) mounted on the body (between the track assemblies) that supports a rotating frame to which is mounted a machine body 14 forming a superstructure. The rotating frame and machine body 14 may support an operator station or cab mounted within the cab, an integrated display 15, operator controls 16 (such as an integrated joystick mounted within the cab), and one or more engines and drive trains that drive the traction device 12 to propel the machine 10. A boom 17 is pivotally mounted to a proximal end of the machine body 14 and may be articulated to the machine body ds by one or more fluid actuated cylinders (e.g., hydraulic or pneumatic cylinders), electric motors, or other electromechanical components. A stick 18 is pivotally mounted to a distal end of the boom 17 and may be articulated to the boom by one or more fluid actuated cylinders, electric motors, or other electromechanical components. A tool 19, such as a bucket, may be mounted to the distal end of the stick 18, optionally articulated to the stick 18 by one or more fluid actuated cylinders, electric motors, or other electromechanical components, to provide a ground engaging tool or other attachment for performing various tasks.

[0018] FIG. 2 is a block diagram of an exemplary embodiment of a sensor fusion system that may be used in conjunction with and to provide input to a swing motion and actuation control system 700 according to the present disclosure. The sensor fusion system may be configured to provide accurate real-time output to a machine state control system 50 configured to control various operational aspects of the machine 10. The machine state control system 50 may be associated with or configured as an integral part of the machine ECM. The machine state control system 50 may also include a swing motion and actuation control system 700, shown in FIG. 7, used to control the swing motion of the swing mechanism of the machine 10. An alternative configuration may include the swing motion and actuation control system 700 as an entirely separate control system. The sensor fusion system may be configured to receive signals from multiple IMUs 210 and additional non-IMU sensors 230, as well as signals indicative of various operator commands, such as signals generated by operator action of a joystick or other input device or operator control 16. "Sensor fusion" is the combination of sensory data or data originating from disparate sources such that the information obtained has less uncertainty than would be possible if the sources were used individually. The sensor fusion system may also be configured to receive information regarding the dimensional design of the particular machine with which the sensor fusion system is associated from dimensional design information database 250. The particular dimensional design information received from design information database 250 for the particular machine may be used by processor 241 associated with the sensor fusion system and configured to derive the kinematics and dynamics of machine 10 through empirical derivation of the kinematics and dynamics in conjunction with kinematics library module 260 and / or using physics-based equations and algorithms. The various sensors and processors may be connected to each other via any suitable architecture, including any combination of wired and / or wireless networks. Furthermore, such networks may be integrated into any local area network (LAN), wide area network (WAN), and / or the Internet.

[0019] The IMUs 210 may be applied to the machine in multiple different positions and orientations, including on different portions of the machine body 14, boom 17, stick 18, and work tool (e.g., bucket) 19. IMUs may be retrofitted in multiple positions and orientations along each of the machine's portions, and may be added and removed depending on the particular machine's application and configuration. The raw data received from each IMU may be processed through a Kalman filter, as described in more detail below. In some implementations, the Kalman filter for each IMU sensor may be included as part of the IMU, while in other implementations the Kalman filter may be part of a separate sensor fusion module provided as part of a separate sensor fusion system.

[0020] The gyroscopes of each IMU detect orientation by angular velocity while the accelerometers of each IMU detect changes in orientation relative to gravity. Gyroscope measurements tend to fluctuate over time since they only detect changes and have no fixed frame of reference. Adding accelerometer data can minimize bias in the gyroscope data and more accurately estimate it to reduce propagation errors and improve orientation readings. Accelerometers may provide more accurate data in static calculations when the system is close to a fixed reference point, while gyroscopes are better for orientation detection when the system is already running. Signals indicative of linear acceleration and angular rate of motion received from the accelerometers and gyroscopes of the IMUs associated with each of the different parts and / or components of the machine may be combined by a Kalman filter to more accurately predict the output angle, velocity, and acceleration of each of the separate components of the machine.

[0021] The Kalman filter associated with each IMU mounted on a separate machine component inputs measurements and finds estimates of future values ​​by varying averaging coefficients to optimize the weights assigned to estimated or predicted values ​​compared to the weights assigned to actual measurements, thereby converging to a best estimate of the true values ​​for the output joint angles, velocities, and accelerations of each machine component. The averaging coefficients are weighted with a measure of the expected uncertainty, sometimes called covariance, to select a value between the predicted and measured values. The Kalman filter estimates the state of the machine using a form of feedback control in a recursive and iterative process, with each iteration including a time update or "prediction" phase and a measurement or "correction" phase. During each iteration performed by the Kalman filter, a gain or weighting is determined by comparing the error in the estimate of the measurement and the error in the actual measurement of the measurement. The Kalman gain is equal to the ratio of the error in the estimate to the sum of the error in the estimate and the error in the actual measurement. A current estimate for the measurement is then calculated from the previous estimate and the new measurement. A new error in the measurement estimate is then determined and fed back for use in determining the gains to be applied in the next iteration. The combined or fused information provided by the Kalman filter can provide accurate, real-time information regarding pitch rate, yaw rate, roll rate, boom angle, stick angle, and other angles, depending on the linkage configuration and the number of IMUs installed on different parts or components of the machine.

[0022] As shown in the exemplary embodiment of FIG. 2, the Kalman filter of the sensor fusion system according to the present disclosure may be configured to estimate the bias of the gyroscopic information provided by the IMU, such as the pitch rate, yaw rate, and roll rate of each component. Because the linear and angular position of a point on each component is calculated by twice integrating the linear acceleration and angular velocity of the motion from the IMU, the calculated information may vary over time and deviations from the actual position may grow as small errors in the measurements are magnified by the integration. Thus, the gyroscopic biasing aspect of the Kalman filter increases the accuracy of the joint angles calculated from the information provided by the IMU. The output joint angles of each of the individual parts or components of the machine may be fused together at the machine level to account for the movement of two or more components relative to the machine while they remain in a substantially fixed orientation relative to each other. For example, both the IMU sensor 25 on the boom 17 and the IMU sensor 26 on the stick 18 of the machine 10 shown in FIG. 1 may indicate a change in the output joint angle relative to the global frame of reference when the boom 17 moves upward, but the actual angle between the boom 17 and the stick 18 may not have changed. Fusing the output joint angles of each of the boom 17 and the stick 18 at the machine level provides this information so that the actual positions of the different points on the separate machine components relative to the machine and global frames of reference may be determined in real time. Accurately determining the actual real time positions of the different points on the separate machine components relative to the machine and global frames of reference also allows for accurate and timely information input to the swing motion and control system 700 shown in FIG. 7, thereby allowing for very precise control and mitigation of any drifting motion of the swing components that may result from the effect of gravity on the swing components when the machine 10 is operating on a sloped or uneven surface.

[0023] As further shown in the exemplary embodiment of FIG. 2, the output joint angles fused at the machine level by the Kalman filter 240 may be received by a kinematics library module 260. The kinematics library module 260 may be configured to receive the output joint angles from the Kalman filter 240, receive dimensioning information specific to the machine 10 from the dimensioning information database 250, and solve for a frame rotation and position at each component or point of interest on the machine. The frame may have an offset applied to the IMU-derived information to solve for any particular point on the machine, and all of the updated position information may be provided to the machine state control system 50 and the slewing motion and control system 700, which may be associated with or programmed as part of the machine ECM.

[0024] In the case of mining machines or other machines in which IMUs may be attached to portions of the machine that rotate or pivot through an arc during operation, three-dimensional position information associated with each of the IMUs attached to those portions of the machine may also be fed back to the pivot compensation module 220. The pivot compensation module 220 may be configured to correct the acceleration information provided by the IMUs attached to the rotating or pivoting portions of the machine by compensating for the central acceleration. This correction of the acceleration information received from the IMU 210 may occur before the information is provided to the Kalman filter 240.

[0025] Additional non-IMU sensors 230 may include any device capable of generating signals indicative of parameter values ​​or machine parameters related to the performance of machine 10. For example, non-IMU sensors 230 may include sensors configured to generate signals indicative of boom and / or stick rotation rate, boom and / or stick position, and work tool angle in the global and machine reference frames. Payload sensors may also be included and configured to provide signals indicative of the payload of machine 10. Slip detection devices may be included and configured to provide signals indicative of slippage of machine 100. Additional non-IMU sensors may include devices capable of providing signals indicative of the slope of the ground on which machine 10 is operating, outside air temperature, tire pressure if traction device 12 is a wheel, hydraulic or air pressure in various fluid operated controls, voltage, current, and / or power supplied to electrical controls, etc.

[0026] The non-IMU sensors 230 may include one or more positioning devices capable of providing signals indicative of the position of the machine and / or the positions of various components of the machine relative to a global or local frame of reference. For example, the positioning devices may include global satellite system devices (e.g., GPS or GNSS devices) that receive or determine position information associated with the machine 10 and may provide an independent measurement of the machine's position. The positioning devices and any other non-IMU sensors 230 may be configured to transmit signals indicative of the received or determined position information or other information related to various machine operating parameters to one or more interface devices, such as an integrated display 15 in the operator cab for displaying real-time machine operating characteristics. The signals from the IMU 210 and the non-IMU sensors 230 may be directed to a controller configured to include a Kalman filter 240, which may be configured for implementation by one or more processors 241 associated with storage 243 and memory 245. The one or more processors 241 of the controller may be configured to perform a Kalman filtering process, including sensor fusion performed in a sensor fusion module 242. The Kalman filter 240 may also be configured to perform gyroscope bias estimation in a gyroscope bias estimation module 244 to compensate for any drift over time of measurements provided by one or more gyroscopes associated with the IMU. In some exemplary embodiments, the positioning device may receive GPS signals as position signals indicative of the position of the machine 10 and provide the received position signals to the processor 241 for further processing. Additionally, the positioning device may also provide a measure of uncertainty associated with the position signals. However, it will be understood by those skilled in the art that the exemplary embodiments of the present disclosure may be modified to utilize other indicators of the position of the machine 10, if desired.

[0027] The non-IMU sensors 230 may also include one or more perception sensors, which may include any device capable of providing scene data describing the environment in the vicinity of the machine 10. The perception sensors may be exemplified by devices that detect and range objects located 360 degrees around the machine 10. For example, the perception sensors may be exemplified by LIDAR devices, RADAR (radio detection and ranging) devices, SONAR (voice navigation and ranging) devices, camera devices, or other devices known in the art. In one embodiment, the perception sensor may include an emitter that emits a detection beam and an associated receiver that receives a reflection of the detection beam. Based on the characteristics of the reflected beam, a distance and direction from the actual detection position of the perception sensor on the machine 10 to the portion of the detected physical object may be determined. By utilizing multiple directional beams, the perception sensor may generate an image of the surroundings of the machine 10. For example, if the perception sensor is exemplified by a LIDAR device or another device using multiple laser beams, a perception sensor such as a laser catcher sensor 28 mounted on the machine's stick 18 may generate a cloud of points as scene data describing the environment in the vicinity of the machine 10. Note that in some embodiments, the scene data may be limited to the front of the machine 10 (180 degrees or less). In other embodiments, the perception sensor may generate scene data for objects located 360 degrees around the machine 10.

[0028] The IMU 210 may include a device that provides angular velocity and acceleration of the machine 10, or more specifically, of a component or portion of the machine to which the IMU is attached, such as the machine body 14, boom 17, stick 18, and bucket or other tool 19. For example, the IMU 210 may include a six degrees of freedom (6DOF) IMU. The 6DOF IMU sensor consists of a three-axis accelerometer, a three-axis angular rate gyroscope, and in some cases, a two-axis inclinometer. Each of the IMUs 210 may be retrofitted to an existing machine by welding the IMU to a machine portion or component where precise information regarding the real-time position, orientation, and motion of that particular portion or component of the machine is desired. The machine's electronic control module (ECM) or other machine controller may receive signals from the IMU and be programmed to implement various machine controls based at least in part on the inputs received from the IMU. In some example implementations of the present disclosure, controls implemented by the ECM in response to signals received from the IMU may include actuation of one or more electric or electrohydraulic solenoid valves configured to control the opening and closing of one or more valves regulating the supply of pressurized hydraulic or pneumatic fluid to one or more fluid actuating cylinders. A three-axis angular rate gyroscope associated with the IMU may be configured to provide signals indicative of pitch rate, yaw rate, and roll rate of the machine 100 or of a particular portion of the machine to which the IMU sensor is attached. A three-axis accelerometer may be configured to provide signals indicative of linear acceleration in the x, y, and z directions of the machine 10 or of a portion of the machine to which the IMU sensor is attached.

[0029] The Kalman filter module 240 may be associated with one or more of a processor 241, storage 243, and memory 245, included together in a single device and / or provided separately. The processor 241 may include one or more known processing devices, such as the Pentium™ or Xeon™ family of microprocessors manufactured by Intel™, the Turion™ family of microprocessors manufactured by AMD™, any of the various processors manufactured by Sun Microsystems, or any other type of processor. The memory 245 may include one or more storage devices configured to store information used by the Kalman filter 240 to perform certain functions associated with the disclosed embodiments. The storage 243 may include volatile or non-volatile, magnetic, semiconductor, tape, optical, removable, non-removable, or other types of storage or computer readable media or devices. The storage 243 may store programs and / or other information, such as information related to processing data received from one or more sensors, as discussed in more detail below.

[0030] In one embodiment, memory 245 may include one or more location estimation programs or subprograms loaded from storage 243 or elsewhere that, when executed by processor 241, perform various procedures, operations, or processes consistent with the disclosed embodiments. For example, memory 245 may include one or more programs that enable Kalman filter 240 to collect data from, among other things, an odometer, a positioning device, a perception sensor, any one or more of IMU 210, and any one or more of non-IMU sensors 230, process the data according to disclosed embodiments, such as the embodiment discussed with respect to FIG. 5, and estimate, in real time, the location of machine 10 and various parts and components of the machine based on the processed data.

[0031] In a particular exemplary embodiment, the position estimation program enables the Kalman filter 240 of the processor 241 to process the received signals and estimate the real-time positions and orientations of different parts or components of the machine 10. The Kalman filter implements a method that can be used to determine accurate measurements observed over time, such as measurements taken in a time series. The general operation of a Kalman filter includes two stages: a propagation or "prediction" stage, and a measurement or "update" stage. In the prediction stage, value estimates from previous time steps in the time series are used to generate a priori value estimates. In the update stage, the a priori estimates calculated in the prediction stage are combined with an estimate of the accuracy of the a priori estimates (e.g., variance or uncertainty) and the current measurements to generate refined a posteriori estimates. The Kalman filter is a multi-input, multi-output digital filter that can optimally estimate the state of a system in real time based on noisy outputs. These states are all the variables required to fully describe the system behavior as a function of time (position, speed, voltage levels, etc.). The multiple noisy outputs can be considered as a multi-dimensional signal plus noise, with the system state being the desired unknown signal indicating the true value of each of the variables. The Kalman filter 240 can be configured to filter the noisy measurements, such as measurements received as signals from the multiple IMUs 210 attached to different parts and components of the machine 10, to estimate the desired signal. The estimates derived by the Kalman filter from the signals provided by the IMU and non-IMU sensors are statistically optimal in the sense that they minimize the mean squared estimation error of the signal. An estimate of the state uncertainty for the noisy measurements may be determined as a covariance matrix, where each diagonal term of the covariance matrix is ​​the variance or uncertainty of a scalar random variable. The gain schedule module 222 can be configured to calculate weights (or gains) to be used in combining each successive predicted state estimate with successive actual measurements to obtain an updated "best" estimate.As the Kalman filter 240 receives multiple measurements over time from the IMU 210 and non-IMU sensors 230, the Kalman filter's recursive algorithm processes each of the multiple measurements sequentially over time, iteratively repeating for each new measurement and using only values ​​stored from the previous cycle (thereby saving memory and reducing computation time).

[0032] In one example embodiment, memory 245 may include one or more pose estimation programs or subprograms loaded from storage 243 or elsewhere that, when executed by processor 241, perform various procedures, operations, or processes consistent with the disclosed embodiments. For example, memory 245 may include one or more programs that enable Kalman filter 240 to, among other things, collect data from the devices described above, process the data according to the disclosed embodiments, such as the embodiment discussed with respect to FIG. 5, and determine a state of machine 10 based on the processed data.

[0033] In particular embodiments, memory 245 may store programmable instructions for configuring Kalman filter 240 (and more particularly, processor 241) to implement a method of using a Kalman filter to estimate states of machine 10. In particular exemplary embodiments, the Kalman filter may be configured to utilize the following equation in its calculations: For the propagation or "prediction" stage, the Kalman filter may be configured to utilize the following general equation:

number

[0034] For the measurement or "update" stage, the Kalman filter may be constructed to utilize the following general formula:

number

[0035] In the above formula,

number

number

number

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[0036] 5 illustrates an example configuration of a Kalman filter 500. In a prediction stage 501 of the Kalman filter 500, the Kalman filter 500 utilizes one or more inputs from one or more IMUs (such as linear acceleration values ​​from an accelerometer of the IMU sensor and angular rate of motion values ​​from a gyroscope of the IMU sensor 520) and a towed gear rate sensor 530 to calculate a priori state estimates of certain state variables (e.g., pitch rate, yaw rate, roll rate, position, velocity, etc.). In the prediction stage 501, the Kalman filter 500 may implement equations (1) and (2). For example, in the prediction stage, the Kalman filter 500 may use the values ​​of the state variables from a previous time step to

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[0037] After the prediction step 501, the Kalman filter 500 calculates the posterior state estimate

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[0038] The Kalman filter may set inputs received from the positioning device and from the inclinometer of the IMU as the measurement yk in equation (4). Additionally, in an exemplary embodiment where machine 10 is a mining machine or other machine that includes parts or components that rotate or swing through an arc during operation, the Kalman filter may receive acceleration values ​​from IMUs located on the rotating or swinging parts of the machine (e.g., boom 17 and stick 18) that have been pre-processed by swing cancellation module 220 to correct for centripetal accelerations that occur during swing operations. As shown in the exemplary embodiment of FIG. 2, the centripetal acceleration correction to the IMU 210 values ​​may be made to the raw acceleration data from IMU 210 before the acceleration data is utilized in equation (4).

[0039] Also, as mentioned above, the Kalman filter 500 in the example embodiment of FIG. 5 may be configured to implement equations (3) and (5) during the update phase. Using the above, the Kalman filter produces as output 503 a posterior state estimate

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[0040] Kalman filters are very useful for combining data from several different indirect and noisy measurements to try to estimate variables that cannot be measured directly. For example, an IMU's gyroscope measures orientation by integrating angular velocity, so the output signal from the gyroscope may vary over time. The IMU's inclinometer and directional heading features (compass) may provide a measurement of orientation that is different, but noisy, but does not vary. In the exemplary embodiment of FIG. 2, the Kalman filter may be configured to appropriately weight the two sources of information using weights retrieved from the gain schedule module 222 to make the most of all the data from each of the sources.

[0041] In determining the state of machine 10 using Kalman filter 240, the filter may also be configured to consider other operating parameters of machine 10. For example, if machine 10 is a mining machine, the Kalman filter may be configured to consider whether machine 10 is mining, dumping, pivoting between a mining position and a dumping position, driving to a new location, etc. When machine 10 is in one or more of the above operating states, certain parameters of the Kalman filter may be altered to reflect a degree of accuracy or confidence in certain input parameters. For example, if machine 10 is driving from one location to another, the Kalman filter may be configured to apply a lower weighting (gain) from gain schedule module 222 to the input from the IMU inclinometer. To reduce the weighting applied to the inclinometer input from the IMU, the Kalman filter may be configured to increase the variance value "R" associated with the inclinometer input in equation (3). Similarly, if machine 10 is mining, the Kalman filter may be configured to increase the weighting applied to the inclinometer input to reflect a higher degree of confidence in the accuracy of the inclinometer input. For example, to indicate greater confidence in accuracy, the Kalman filter may be configured to apply a higher weighting (gain) from the gain schedule module 222 to the input from the IMU inclinometer, decreasing the “R” value associated with the inclinometer input.

[0042] 6 and 7, the closed hydrostatic loop 660 in conjunction with the swing motion actuation and control system 700 allows for precise control of the commanded displacement of the hydrostatic swing pump 686 and the commanded output pressure controlled by a swing pump electronic pressure reducing valve (ePRV) 664 associated with the hydrostatic swing pump 686. The resulting swing pump commanded displacement and swing pump commanded output pressure from the ePRV may be controlled to mitigate any drifting of the swing mechanism, including the boom 17, stick 18, and work tool 19 of the machine 10, which may be caused by gravity effects when the machine 10 is operating on sloping or uneven ground.

[0043] 7, in one exemplary implementation of swing motion actuation and control system 700, the control system may be configured to determine and implement swing pump displacement tilt control, swing pump ePRV tilt control, swing pump displacement brake tilt control, and swing pump ePRV brake tilt control. Swing motion actuation and control system 700 may be configured to determine and implement swing pump displacement tilt control by commanding an offset to the desired hydrostatic pump displacement, which is a function of predisposing factors including operator input 722 to hydrostatic pump 686, tilt control 724, brake control 726, brake tilt control 727, which is a function of the amount of tilt at which machine 10 is operating and the attitude of the machine, desired engine torque limits and / or characteristics of the particular machine, age of the machine, desired wear characteristics, and other consumer determined inputs. The payload carried by tool 19 and the inertial masses of the swing components and payload may be inputs to swing motion actuation and control system 700.

[0044] In one exemplary implementation, the swing operation actuation and control system 700 may be configured to command an offset in the desired pump displacement of the hydrostatic pump 686 intended to increase pump displacement when a machine (such as the excavator 10 of FIG. 1) swings the swing component and payload carried by the tool 19 and a machine operator requires a greater fluid flow to keep the swing component motion at a constant speed while commanding the machine to move the boom 17, stick 18, and tool 19 in a direction of increasing incline. This commanded offset to increase pump displacement may be implemented when the machine is positioned on a slope, mining is performed at a lower point on the slope in the direction of gravity, and the boom 17, stick 18, tool 19, and carried payload are commanded to swing from a lower point to a higher point in the direction of gravity. The control system 700 may also be configured to automatically increase pump displacement for relatively large pump displacements when the detected inertial mass of the swing component and / or payload is relatively large. When the machine 10 is operating on flat ground, the swing motion actuation and control system 700 may be configured to maintain the displacement output of the hydrostatic pump 686 at a constant level since there are no gravitational effects that would tend to cause the swing mechanism to drift.

[0045] Similarly, the swing operation actuation and control system 700 may be configured to command an offset in the desired pump displacement of the hydrostatic pump 686 intended to reduce pump displacement when a machine (such as the excavator 10 of FIG. 1) swings the swing components and payload carried by the tool 19 and requires less fluid flow to maintain the swing components' motion at a constant speed while the machine operator commands the machine to move the boom 17, stick 18, and tool 19 in a direction that decreases the slope. Additionally, the control system 700 may be configured to command an offset in pump displacement in a direction opposite to the pump displacement resulting from the swing command executed by the operator on center. These commanded offsets may be implemented when the machine is positioned on a slope and mining is performed at a high point on the slope in the direction of gravity and the boom 17, stick 18, tool 19, and carried payload are swing from the high point to the low point in the direction of gravity. The control system 700 may also be configured to automatically reduce the pump displacement to a relatively small pump displacement when the detected inertial mass of the swinging components and / or payload is relatively small compared to when the detected inertial mass of the swinging components and / or payload is relatively large. In some implementations, the control system 700 may be configured to automatically reduce the pump displacement to a relatively small pump displacement even with an increase in the slope at which the machine 10 is operating if the inertial mass being moved is relatively small by an amount sufficient to counteract the gravity effect caused by the relatively large slope. The control system 700 may be configured to determine that the hydrostatic pump displacement and the resulting swirl flow provided to the hydraulic motors 682, 684 may be equivalent to moving a smaller inertial mass on a larger slope to moving a larger inertial mass on a smaller slope.

[0046] The swing operation actuation and control system 700 may be configured to determine the amount of offset to the desired hydrostatic pump displacement based on predisposing factors, which may include, but are not limited to, the magnitude of the inertial mass of the swing components and the payload being carried, as well as the roll, yaw, and pitch rates of the machine 10. For example, as the inertial mass swung by the machine 10 increases, the amount of offset to the desired hydrostatic pump displacement may be proportionally increased, and as the inertial mass swung by the machine 10 decreases, the amount of offset to the desired hydrostatic pump displacement may be proportionally decreased. Similarly, as predisposing factors, such as the roll, yaw, and / or pitch of the machine 10 increase, the amount of offset to the desired hydrostatic pump displacement may be proportionally increased. As the same predisposing factors decrease, the amount of offset to the desired hydrostatic pump displacement may be decreased. In some example implementations, the additional predisposing factors may include a preposition scale, e.g., set from 0 to 1, which provides additional compensation to the pump displacement designed to smooth the effects of swing engagement and brake release when the machine 10 is operating on an incline.

[0047] 7, the swing operation actuation and control system 700 may be configured with a pressure control device, such as a swing pump electronic pressure reducing valve (ePRV) control 740. The swing pump ePRV control 740 may be configured to determine and implement an offset to the swing pump output pressure. The swing pump ePRV control 740, or another closed loop control that adjusts pump displacement based on system pressure, may be configured to control an ePRV command or another pressure command, including commanding a desired hydrostatic pump output pressure or force command 742, a tilt control pump output pressure or force command 744 that is a function of predisposing factors including the amount of tilt the machine 10 is operating at and the attitude of the machine, a brake control 746, a brake tilt control 747, and an offset to the desired force command to the force to delta pressure 748. The swing control pressure output by the hydrostatic pump 686 can be supplied to the hydraulic motors 682, 684 in the closed loop 660, and the hydrostatic loop pressure sensors 692, 694 provide feedback to enable the swing pump ePRV control 740 to determine the swing control pressure 745 and adjust the swing pump ePRV within the closed loop control 749.

[0048] The swing pump displacement brake tilt control included in brake tilt control 727 may include braking logic that accomplishes braking by offsetting the current pump displacement or commanding the pump in the direction opposite the swing rotation by an amount necessary to slow down the swing motion. The amount of braking offset may increase as the slope at which machine 10 is operating increases or as the amount of inertial mass of the swing components and payload increases. The amount of braking offset may decrease as the slope at which machine 10 is operating decreases or as the amount of inertial mass of the swing components and payload decreases. In some implementations, brake tilt control 727 may be configured to decrease the amount of pump displacement offset as the slope increases but also as the inertial mass decreases because the gravitational effect of the slope is offset by the lower inertial mass. The swing pump ePRV brake tilt control 747 may also be implemented by commanding a maximum value to the pilot ePRV when braking machine 10.

[0049] 3 and 4 show an example implementation of a machine state control system utilizing output from a sensor fusion system having a Kalman filter according to the present disclosure. A detailed description of FIG. 3 and FIG. 4 is provided in the next section. [Industrial Applicability]

[0050] The disclosed machine state control system 50 and swing motion and control system 700 may be applied to any machine or machine system that would benefit from accurate real-time sensing of the variables necessary to fully describe the system's behavior as a function of time (position, velocity, linear acceleration, and angular rate of each machine component) and from accurate compensation and control of the swing mechanism to mitigate the effects of gravity on the drift of the swing components away from their commanded positions. The disclosed sensor fusion system in conjunction with multiple IMU and non-IMU sensors retrofitably mounted to different parts or components of the machine may provide improved estimation of all of the positions and orientations of the different machine components by utilizing Kalman filters associated with each IMU mounted to each of the multiple machine components.

[0051] In some example implementations of the disclosed sensor fusion system, the Kalman filter 240 may utilize machine parameters, odometer signals, and IMU inputs received from IMUs attached to various parts and components of the machine to propagate or "predict" the state of the machine. For example, the Kalman filter 240 may predict the state of the position, forward velocity, angular velocity, joint angles, and angular orientation (pose) of each of the machine components relative to the global and machine reference frames, and of the machine itself relative to the global reference frame. In addition to signals indicative of the acceleration and angular velocity of the motion received from each IMU, each of the Kalman filters associated with each IMU attached to the different machine components may receive signals from various different non-IMU sensors, such as odometers, proximity sensors, and other perceptual sensors, indicative of the distance traveled by the machine component during operation, or the distance between the machine component and a potential obstacle. The Kalman filter may also calculate the distance traveled by the machine 10 itself by multiplying the rotational speed of the traction device by the received scaling factor. The Kalman filter may also calculate the velocity of the machine 10 or a part or component of the machine by integrating signals indicative of linear acceleration from IMU sensors attached to a particular part or component of the machine. The Kalman filter may use signals from the IMUs to calculate the velocity of the machine, or of a part or component of the machine to which one or more IMUs are attached, weighting the resulting velocities to generate a predicted velocity. In some implementations, the distance traveled by the machine itself may be adjusted to account for machine slippage. Each Kalman filter may also receive signals from one or more IMUs indicative of the angular rates of motion (roll rate, yaw rate, and pitch rate) of the machine or part of the machine. By integrating the angular rates of motion, the Kalman filter 240 may determine the attitude or angular orientation (roll, heading, and pitch) of each machine component or of the machine itself.

[0052] The Kalman filter may utilize one or more of the propagated states to propagate or "predict" the position of the machine 10, or a portion or component of the machine, relative to the machine reference frame and relative to the global reference frame. For example, by utilizing the angular rate of motion and the predicted velocity, the Kalman filter may predict the position of the machine or a component of the machine. As described above, the Kalman filter may also calculate an uncertainty for the predicted position, which may be set equal to the uncertainty as specified by the error covariance matrix of the Kalman filter. Various positions on the machine may be determined independently from the IMU. After determining the independent position measurements, the Kalman filter may be configured to fuse the predicted position information with the independent position measurements to determine an updated position estimate for each position. The updated position estimate may be determined utilizing a Kalman filter measurement update equation. After determining the updated position estimate for the machine 10, the Kalman filter 240 may also determine the bias of each of the IMUs. As described above, an example of a bias parameter estimate that may be performed by the Kalman filter is an estimate of the bias of a gyroscope-determined angular position after integration of the measured angular rate.

[0053] In one exemplary application of the machine state control system according to the implementation of the present disclosure, accurate, updated, real-time information regarding the position and orientation (pose) of the machine and machine parts or components may provide feedback to the information exchange interface 350 to implement machine controls that achieve optimal positioning and operation of the machine and machine components to improve productivity and reliability. In some implementations, the feedback may assist the operator by guiding the operator on how to implement controls that result in improved machine footing and stability, and thus improved productivity. In other implementations, the information received at the information exchange interface 350 may result in the generation of autonomous or semi-autonomous control command signals that are provided to various machine systems and subsystems to effect changes in machine pose and changes in the relative positions and orientations of the machine components. In one exemplary implementation, as shown in FIG. 3, sensor feedback from machine sensors regarding the positions and speeds of the machine linkages of the boom and stick of the excavator, machine pitch and roll rates, and swing angles may be fused with signals provided by the vision and perception sensors 320 and signals received from various operator controls 324 that indicate the location of obstacles or other features in the work site. The fused data may be provided to information exchange interface 350 to effect generation of control command signals that modify the operation of various solenoid valve actuators, throttle controls, fluid cylinder actuators, electrical controls, and motion controllers to provide optimal positioning of the machine during mining operations. Information exchange interface 350 may, in some implementations, provide accurate, real-time updated information to a human operator as well as act as an information interface with autonomous or semi-autonomous control systems that use the information to process control command signals for automatic or semi-automatic operation of various machine systems and machine subsystems.

[0054] In mining with an excavator, the machine state control system 50 may determine from historical and / or empirical data on the kinematics and dynamics of the excavator that the body of the machine should be parallel to the idler wheels for the track of the excavator directed to the forward linkage for best stability during mining. Feedback to the information exchange interface 350 on the machine pitch and roll may also be provided, such that if the track of the excavator is directed forward, and footing under the idler wheels is poor, the information exchange interface may result in the generation of control command signals that cause a change in the attitude of the machine to improve footing and prevent the machine from pitching and rolling, and further manipulate the machine to fully contact the ground and counter the mining forces. The angle of the bucket or other tool, and the applied forces achieved by the particular orientation of the stick and boom at any particular time during the mining operation, may also affect the mining efficiency of the excavator. The machine state control system according to the present disclosure may provide continuously updated feedback information to the information exchange interface regarding the real-time efficiency of the position of the linkage during mining. The feedback information may change the bucket angle or stick position during mining to improve the efficiency of the machine and also improve the life of the machine by achieving improved kinematics of the linkage resulting in better loading of the bucket, faster loading of the bucket, and / or better use of machine power. Information provided from the machine state control system to the information exchange interface may also change the control command signals to change the attitude of the machine to avoid mining with the body oriented at 90 degrees to the linkage, which is not optimal for stability or mining. If the machine control responds to the information provided at the information exchange interface 350 and implements the control such that the body of the machine is such that the mining linkage is parallel to the idler wheels for the excavator tracks directed at the forward linkage, then as a result, energy is not wasted in lifting the machine off the ground and the production rate is improved with the resulting cycle time reduction, reducing the load on the final drive components, increasing the life of the machine and reducing downtime.

[0055] In another exemplary application of the machine state control system according to the present disclosure, as shown in FIG. 4, a sensor fusion system may receive, combine, and process operator command inputs received from operator controls 324 with inputs from IMU and non-IMU machine sensors measuring linkage position, fluid pressure, engine speed, machine and machine component position and orientation (including pitch rate, yaw rate, and roll rate), inputs from a vision system 320 including perception sensors providing signals indicative of object presence and position, and inputs from hydraulic system sensors 430. In some implementations, signal inputs from hydraulic system sensors may indicate a condition in which more pressure on the fluid actuating cylinders is needed to avoid stalling. To avoid unnecessary stress on the machine, components, and structure, the machine state control system 50 may be configured to automatically adjust the boost pressure of the hydraulic pump 450 and command a controlled ramp in the relief pressure set point of one or more relief valves 425, if possible, without causing damage or instability to the machine. The fused sensor output from the sensor fusion system according to various embodiments of the present disclosure enables the machine state control system to determine the time of machine stop or imminent stop during lifting or mining operations. The machine state control system may then determine the timing and degree of acceleration of the relief pressure setting of the relief valve 425 based on the fused sensor feedback information in combination with operator commands.

[0056] In one exemplary implementation, the mining machine can lift heavy loads or perform mining operations, the boom actuating cylinder is at its maximum pressure, the pump output pressure is equal to the pressure of the boom actuating cylinder while the bucket and stick are still moving, and the boom is stationary. The machine state control system can determine whether the machine is in an unstable and / or over-stressed state from accurate and real-time fused sensor data received from a sensor fusion system that includes data indicating the pitch rate and roll rate of the machine. The machine state control system can determine that the relief pressure of the boom actuating cylinder can be increased in a controlled ramp to move the boom again without exceeding the allowable stress level and while maintaining the stability of the machine.

[0057] In an additional exemplary implementation of a machine state control system according to the present disclosure, the machine state control system may output commands to adjust the maximum output pressure of pumps that provide pressurized fluid to various fluid actuating cylinders on the machine. As shown in FIG. 4, the machine state control system 50 receives fused sensor data from a sensor fusion system, including operator input, measured linkage positions, fluid pressures, engine speed, machine pitch and roll rates, and scene data such as object presence and location. The machine state control system may determine the task being performed and adjust the maximum pressure allowed electronically in the system through high pressure cutoffs established for different tasks. This allows the system to prevent excessive stress on various components and structures of the machine and also prevent over-torquing of components or high speed slamming of components into objects by slowing pump flow, varying slew motor displacement, or overriding valve commands received from operator input. For machine components such as the boom and stick of an excavator, which may include an associated dedicated hydraulic slewing circuit for moving the boom and stick between a digging position and a dumping position, the hydraulic or slewing motor displacement in the slewing circuit may be electronically limited according to real-time output commands received from the machine state control system. In some implementations, one or more pumps provided in the slewing circuit or other hydraulic circuits on the machine may be adapted for a zero or near-zero displacement work configuration. The machine state control system 50 may determine the work being done and, in certain circumstances, adjust one or more pump displacements to zero or near-zero displacement. One or more pump displacements may be adjusted to a value low enough that only system leakage is compensated for, and movement of the linkage by the fluid actuating cylinders supplied by the one or more pumps in a very low displacement mode does not cause excessive loads on the linkage or other machine components.In addition to, or as an alternative to, overriding valve commands or other control commands received from operator input in semi-autonomous mode, the machine state control system 50 may provide feedback directly to the operator through one or more displays associated with the information exchange interface 350, or through a joystick, the driver's seat, haptic feedback on a head-up display (HUD) projected on the driver's windshield, or through audio or other stimuli implemented to guide the operator and improve future operational control commands.

[0058] As described above, machine state control system 50 may include a swing motion and control system 700, which may be associated with a closed hydrostatic loop 660. The closed hydrostatic loop 660 may fluidly connect an independent, dedicated hydrostatic swing pump 686 to one or more hydraulic motors 682, 684 operably connected to the rotating frame and machine body 14 of the machine 10 for controlling the swing motion of the boom 17, stick 18, and tool 19 relative to the undercarriage or body of the machine 10.

[0059] It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed method and system for determining the real-time state of a machine. Other embodiments and implementations will be apparent to those skilled in the art from consideration of the specification and practice of the disclosed machine state control system. It is intended that the specification and examples be considered as exemplary only, with the true scope being indicated by the following claims and equivalents thereof.

Claims

1. A swing motion control system (700) for an earthmoving machine (10), comprising: a closed loop hydraulic circuit including a hydrostatic slew pump (686) fluidly connected to at least one hydraulic slew motor (682, 684) configured to control a slew mechanism of the earthmoving machine (10); a pressure control device (664) configured to control the pressure of a fluid supplied to the hydrostatic swirl pump (686) to control the pressure output by the hydrostatic swirl pump (686); A control device (700), monitoring and processing signals received from sensors and operator inputs, the signals received from the sensors being indicative of the attitude of the machine, including the position of the machine and the amount of tilt at which the machine is operating, as well as the inertial mass of a swing component and payload moved by the swing mechanism of the machine; and a controller (700) configured to control at least one of an offset to a desired pump displacement by the hydrostatic slewing pump (686) or an offset to an output pressure from the hydrostatic slewing pump (686) based on at least one of an amount of tilt at which the machine is operating or the inertial mass of the slewing components and payload; The control device includes: commanding the hydrostatic slewing pump (686) to said offset amount relative to desired pump displacement such that said pump displacement is increased if the machine (10) requires a greater amount of hydraulic fluid flow to slewing the slewing component and the payload and to maintain the slewing component movement at a constant velocity while a machine operator is commanding the machine to move the slewing component in a direction to increase inclination; or a swing motion control system (700) configured to at least one of: swing the swing component and the payload while a machine operator commands the machine to move the swing component in a direction to decrease tilt; and command the offset amount to a desired pump displacement by the hydrostatic swing pump (686) such that the pump displacement is decreased when the machine requires less hydraulic fluid flow to maintain motion of the swing component at a constant speed.

2. 2. The swing motion control system (700) of claim 1, wherein the controller is configured to monitor and process signals indicative of the inertial mass of the swing components and the payload, including sensor-generated signals indicative of head-end pressure of one or more hydraulic cylinders operatively connected to a boom of the machine (10), the head-end pressure being a function of at least one of a roll angle, a tilt, or a position orientation of the machine.

3. 2. The swing motion control system (700) of claim 1, wherein the controller is further configured to progressively disengage a brake system of the machine (10) while simultaneously controlling at least one of the offset amount to a desired pump displacement by the hydrostatic swing pump (686) or the offset amount to a pump output pressure from the hydrostatic swing pump (686).

4. 2. The swing motion control system (700) of claim 1, wherein the controller is configured to control the amount of offset to a desired pump displacement by the hydrostatic swing pump (686) based on at least one of an amount of tilt at which the machine (10) is operating or the inertial mass of the swing components and payload.

5. 2. The swing motion control system (700) of claim 1, wherein the controller is configured to control the amount of offset to the pump output pressure from the hydrostatic swing pump (686) based on at least one of an amount of tilt at which the machine (10) is operating or the inertial mass of the swing components and payload.

6. 2. The swing motion control system (700) of claim 1, wherein the controller is configured to automatically increase pumping displacement by the hydrostatic swing pump (686) to a relatively large pumping displacement when the inertial mass of the swing components and the payload is relatively large.

7. 2. The swing motion control system (700) of claim 1, wherein the controller is configured to determine the offset amount for desired pump displacement by the hydrostatic swing pump (686) based on predisposing factors including one or more of the magnitude of the inertial mass of the swing components and the payload, and a roll rate, a yaw rate, and a pitch rate of the machine.

8. 2. The swing motion control system (700) of claim 1, wherein the controller is configured to control the offset amount to the output pressure from the hydrostatic swing pump (686) as a function of one or more factors including the desired hydrostatic swing pump output pressure or force command, a tilt control pump output pressure or force command that is a function of the amount of tilt at which the machine (10) is operating and the attitude of the machine, a brake control on a level surface, and an operator input to a brake tilt control that is a function of the amount of tilt at which the machine is operating and the attitude of the machine.

9. 1. An earth moving machine (10) including a swing motion control system (700), the swing motion control system comprising: a closed loop hydraulic circuit including a hydrostatic slew pump (686) fluidly connected to at least one hydraulic slew motor (682, 684) configured to control a slew mechanism of the earthmoving machine (10); a pressure control device (664) configured to control the pressure of a fluid supplied to the hydrostatic swirl pump (686) to control the pressure output by the hydrostatic swirl pump (686); A control device, monitoring and processing signals received from sensors and operator inputs, the signals received from the sensors being indicative of the attitude of the machine, including the position of the machine and the amount of tilt at which the machine is operating, as well as the inertial mass of a swing component and payload moved by the swing mechanism of the machine; and a controller configured to control at least one of an offset to a desired pump displacement by the hydrostatic slewing pump (686) or an offset to a pump output pressure from the hydrostatic slewing pump based on at least one of an amount of tilt at which the machine is operating or the inertial mass of the slewing components and payload; The control device includes: commanding the hydrostatic slewing pump (686) to said offset amount relative to desired pump displacement such that said pump displacement is increased if the machine (10) requires a greater amount of hydraulic fluid flow to slewing the slewing component and the payload and to maintain the slewing component movement at a constant velocity while a machine operator is commanding the machine to move the slewing component in a direction to increase inclination; or slewing the slewing component and the payload while a machine operator commands the machine to move the slewing component in a direction to decrease slope, and commanding the offset amount to a desired pump displacement by the hydrostatic slewing pump (686) such that the pump displacement is decreased when the machine requires less hydraulic fluid flow to maintain motion of the slewing component at a constant speed.

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