System for mitigating unintended movement of a work machine

Abstract

Provide a system that mitigates unintended movement of a work machine. The device can include a sensor circuit for detecting mechanical movement of the work machine along a surface. The device can further include a processing circuit that receives mechanical movement information or force-related information and determines the likelihood of unwanted movement occurring. The processing circuit can also provide a mitigation control signal for mitigating unwanted movement if it determines that the probability of unwanted movement occurring exceeds a threshold.

Description

Technical Field

[0001] The present disclosure relates to construction machinery, and more particularly, to systems and methods for mitigating unintended movement of construction machinery.

Background Art

[0002] Work machines may move unintentionally during work operations. For example, in the case of an excavator, due to causes such as the reaction force of excavation or slipping on a muddy road, the work machine may be unintentionally dragged forward during the excavation operation. Unintended movement may cause incorrect cutting, incorrect dumping, and a decrease in efficiency, especially when there is no operator who can make adjustments inside or near the work machine. Therefore, there is generally a need for a system that reduces the occurrence and amount of unintended movement and compensates for it when it occurs.

[0003] U.S. Patent No. 7,756,622 describes reducing the movement of a construction vehicle using a method adaptable to changes in the situation of the construction machinery.

Summary of the Invention

[0004] In one example according to the present disclosure, an apparatus includes a sensor circuit for detecting mechanical movement or the possibility of mechanical movement of a work machine along a surface, and a processing circuit coupled to the sensor circuit, receiving mechanical movement information, determining the possibility of occurrence of an undesirable movement, and configured to provide a mitigation control signal for mitigating the undesirable movement when it is determined that the probability of occurrence of the undesirable movement exceeds a threshold value.

Brief Description of the Drawings

[0005] The drawings are not necessarily drawn to scale, but the same numbers may represent similar components from different viewpoints. Similar numbers with different letter suffixes may represent different instances of similar components. The drawings generally show, by way of example and not limitation, the various embodiments described herein.

Figure 1

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DETAILED DESCRIPTION OF THE INVENTION

[0006] FIG. 1 shows a side view of an excavator 100 according to the present disclosure. Although the exemplary embodiment is described with reference to the excavator 100, the examples according to the present disclosure are applicable to various types of work machines, in which unintended movements may occur during excavation or swinging by a bucket or boom attached to the work machine, or the tracks or wheels may accidentally slip on the surface during operation.

[0007] Referring to FIG. 1, the excavator 100 may include an upper structure 102, a lower structure 104, and a working element 106. The upper structure 102 may include a main body 108 and a cab 110. The cab 110 is mounted on the main body 108. The cab 110 may include a device for receiving an input from an operator of the machine that may direct the desired operation of the excavator 100. Specifically, the cab 110 may include one or more driver interface devices. Examples of driver interface devices include, but are not limited to, a joystick, a travel control lever, and / or pedals (none of which are shown but are well known in the industry).

[0008] The lower structure 104 may include a pair of tracks 112 (e.g., a transport device) for driving the excavator 100 along a path. The pair of tracks 112 is driven by a hydraulic transmission or by an electric drive motor driven by a prime mover such as an internal combustion engine (not shown).

[0009] The working element 106 includes a boom 114, an arm (e.g., a "stick") 116, and a working tool 118. The working tool 118 can be provided with, for example, a bucket. The boom 114 can be mounted on the main body 108 at the swivel point 120. The boom 114 is adapted to swivel vertically by a boom hydraulic cylinder 122. The first end 124 of the boom hydraulic cylinder 122 can be coupled to the main body 108. The second end 126 of the boom hydraulic cylinder 122 can be coupled to the boom 114. The boom 114 can be coupled to the stick 116.

[0010] By extending and retracting the arm hydraulic cylinder 128, the stick 116 is moved relative to the boom 114. The first end 130 of the arm hydraulic cylinder 128 is coupled to the boom 114. The second end 132 of the arm hydraulic cylinder 128 is coupled to the stick 116. The stick 116 can further be coupled to the working tool 118.

[0011] The working tool 118 is moved relative to the stick 116 by extending and retracting the working tool hydraulic cylinder 134. The working tool hydraulic cylinder 134 moves the working tool 118 via a bucket linkage assembly 136. The first end 138 of the working tool hydraulic cylinder 134 can be coupled to the stick 116. The second end 140 of the working tool hydraulic cylinder 134 is coupled to the bucket linkage assembly 136. In one embodiment, the bucket linkage assembly 136 can be referred to as a working tool linkage assembly and can be used to couple any type of working tool.

[0012] A number of different working tools 118 can be attached to the excavator 100 and controlled by a machine operator. The working tool 118 includes any device used to perform a specific task, such as a blade, a fork device, a bucket (shown in FIG. 1), a shovel, a cutting device, a gripping device, and / or other task execution devices known in the art.

[0013] A controller 150 can be provided for electrically controlling various aspects of the work machine 100, including controlling movement to prevent or adjust unintended movement of the work machine 100. For example, the controller 150 can transmit and receive signals from various components of the work machine 100 during operation of the work machine 100. The controller 150 can include an on-board memory or can have access to a memory at a remote location. For example, the work machine 100 and its controller 150 can be wirelessly communicatively connected to a remote device 154 that can include a memory 156 using a connection 152.

[0014] The work machine 100 can include a sensor circuit for detecting translational or rotational movement of the work machine along a surface, or mechanical movement in a horizontal direction, or rolling, pitching, or yawing movement. For example, the work machine 100 can include one or more location sensors 158 connected at one or more locations. The location sensor 158 can identify the location of the work machine 100 and can include or be provided with components of a global positioning system (GPS). For example, the location sensor 158 can include a GPS receiver or other such device, and the location sensor 158 can communicate with one or more GPS satellites to continuously, substantially continuously, or at various time intervals identify the location of the work machine 100. In some implementations, a processing circuit (e.g., the controller 150) can be coupled to this sensor circuit to receive mechanical movement information for control using software, but the embodiments are not limited thereto. The sensor circuit can also include cameras such as cameras with visual odometry tracking capabilities, ranging sensors, and other sensors.

[0015] Horizontal movement can include movement in the front-rear direction and the left-right direction. Additionally, other movements such as roll, pitch, and yaw can also be detected. For example, an unexpected roll can have an adverse effect on excavation. Therefore, when a roll exceeding a threshold value is detected, movement compensation of the track can be performed, for example, by alternately rotating the tracks in reverse to stabilize the ground. A change in pitch exceeding the threshold value can potentially reduce the optimal breakout force during excavation and can be processed in the same way as roll. Yaw movement can usually be compensated or processed by the offset of the excavation trajectory planner, and usually, the other compensations or relaxations described here are not triggered. Therefore, the processing circuit 150 can detect that the work machine has moved beyond the allowable linear or angular displacement at the threshold boundary from the work location.

[0016] During operations such as excavation, the work machine 100 may move unintentionally. This movement is more likely to occur during autonomous operation without an operator to prevent irrelevant movement, but even when an operator is present, unintentional or undesirable movement may occur. For example, during autonomous excavation, the work machine 100 may be pulled towards the work tool 118 (e.g., a bucket) regardless of the movement of the track 112. This pulling and other unintentional movements may be caused by strong reaction forces from excavation or the presence of slippery or sloping ground around the work machine 100. Unintentional movement can cause incorrect cutting and incorrect dumping, and there may be a decrease in efficiency due to excavation at non-ideal angles. Additionally, unintentional movement of the work machine 100 can result in continuous dry excavation where the work machine 100 cannot reach the end condition based on the location of the bucket. For example, the bucket or other work tool 118 may not be able to move to the end location due to undesirable movement. The end location can be defined, for example, as the location where the bucket is moved to a sufficient depth in the vertical direction, a sufficient range in the horizontal direction (in front of the chamber), or at a sufficient angle in the yaw angle of the chamber to completely excavate the required amount of material to complete a trench, foundation, etc.

[0017] To address these concerns and others, systems, apparatuses, and methods according to some embodiments can provide controlled movement to prevent or adjust unintended movement of the work machine 100.

[0018] FIG. 2 shows movement for alleviating and compensating for undesirable movement of the track 112 (and movement of the work machine 100 as a whole) according to the present disclosure. The compensation operation can be executed at a timing determined by the operator or the customer of the machine, such as during the swing-back period after dumping or before returning to the position for the next excavation cycle. Undesirable movement is detected based on the reaction force from the bucket 118, the movement distance of the track 112, the movement distance of the work machine 100, the movement speed of the track 112, the movement speed of the work machine 100, and other parameters. The movement distance and speed can be provided, for example, by an inertial measurement unit (IMU), GPS 158, or another sensor or device.

[0019] As alleviation, it can include lifting the boom 114 (e.g., operation 200). To alleviate movement during excavation, the bucket 118 can be dumped (e.g., dumped outwardly in operation 210), thereby reducing the horizontal soil interaction and the reaction force. The reaction force can be defined as follows. When the work machine 100 is excavating, the stick 116 rotates towards the machine, and the bucket is curled in operation 202, resulting in a reaction force from the soil / material in the opposite direction, i.e., horizontally outward from the work machine 100 and downward in the opposite direction to the curl direction of the bucket 118. Other alleviating movements include the protruding operation 208 and the like.

[0020] When the work machine 100 exhibits an undesirable movement exceeding a threshold amount (even if it is a relaxation movement or before a relaxation movement is attempted), a compensation movement can be executed. For example, as indicated by an IMU, GPS, etc., when the work machine 100 moves outside the area where the work is to be executed due to the undesirable movement, or when it moves away from the original location of the work machine 100 before the undesirable movement, a compensation movement can be executed. In addition to the above relaxation operations, the compensation movement can include operations to move the track forward or backward in operations 250 and 252, respectively. The track 112 can also be moved to move the entire work machine 100. For example, when the work machine 100 moves forward erroneously due to a slope, a slippery road surface, or the movement of the bucket 118, the work machine 100 can be moved backward. Other operations can include an operation 204 to lower the boom and an operation 206 to insert the stick, etc.

[0021] The processing circuit (e.g., the controller 150, the remote device 154 (FIG. 1)) can compensate for the misaligned posture of the work machine 100 and return the work machine 100 to a position with a desired posture (where "posture" can be understood as the translation and direction of the machine in the world space). In some examples, the movement compensation action is executed during the post-dumping swing-back phase but before the next excavation. However, it can also be controlled so that the action occurs at different points in other phases of the operation of the work machine 100. Other phases can include, for example, when the bucket 118 is stationary after dumping, when the bucket 118 is lifted out of the pit and stationary after excavation, etc. However, the movement when the bucket 118 is in the pit is usually not executed in most situations because it may generate a force that cannot be controlled by the link mechanism. The compensation and relaxation actions can include other movements or combinations of the above movements.

[0022] Figure 3 shows a flowchart of process 300 for mitigating and compensating for unintentional movement according to the present disclosure. Process 300 can be executed, for example, by the processing circuitry of controller 150 or remote device 154, but embodiments are not limited thereto.

[0023] Process 300 begins with operation 302 involving the start of operation of work machine 100, for example, the start of excavation of an excavator and other work machines 100 capable of performing excavation (e.g., backhoe, mini-excavator, mining shovel, electric rope shovel, wheel loader, etc.). Generally, when an excavation cycle is started (e.g., when bucket 118 starts excavation), the processing circuitry can perform, in operation 304, a mitigation for detecting or determining the likelihood that unwanted movement of work machine 100 will occur in operation 304. Such detection can be based on the reaction force from bucket 118, the movement distance of track 112 or work machine 100, or the movement speed of track 112 or work machine 100 (based on IMU and / or GPS). Other indicators can be applied to other types of work machines 100. For example, by monitoring the hydraulic signal(s) of boom 114 and monitoring the hydraulic cylinder (usually the head end) of stick 116 or bucket 118, and indicating a threshold force, a mitigation action can be executed.

[0024] In operation 306, if unwanted movement or a likelihood thereof is detected, the processing circuitry can perform mitigation actions similar to those described above. For example, the processing circuitry can control to raise boom 114, dump bucket 118 downward, and / or move stick 116 outward, sequentially, simultaneously, or any combination thereof. By performing the mitigation actions, the horizontal soil interaction and the downward pitching movement of the chamber can be reduced, thereby reducing the reaction force.

[0025] Even after the processing circuit supplies the relaxation control signal and even after the work machine 100 executes the relaxation operation, the work machine 100 may still move several inches or even several feet. As described above, especially when there is no operator to prevent such movement, it may have an adverse effect on the excavation operation. Therefore, the processing circuit can determine whether the unwanted movement is large enough to move the work machine 100 outside the threshold range of the original excavation location or the desired excavation location. The threshold range can be defined, for example, as a circular or elliptical threshold with respect to the posture of the center of rotation of the machine, or as a square or rectangular threshold (front-back direction and left-right direction). Other thresholds, such as those referring to the pitch angle or roll angle of the machine, can also be considered. If the unwanted movement is large enough, in operation 308, the processing circuit can execute compensation or select the time point to start executing compensation, and further select a compensation action.

[0026] Although it can be set according to various excavation stages, the compensation action is particularly useful during the "swing back" stage of the excavator (after dumping and before the next excavation cycle). This is because executing compensation during "swing back" can minimize the impact of compensation on active excavation or dumping. In any case, once the optimal compensation time is determined, in operation 310, the processing circuit can apply track commands to the left / right tracks to move towards the original ideal location (for example, the location of the work machine 100 before the unwanted movement occurs) when the navigation planner is executed and the optimal navigation path is determined. In operation 312, excavation can be executed or resumed.

[0027] In one example, the compensating movement should be as smooth as possible, and thus, the movement command should have the minimum effect necessary to return the work machine 100 to its original position. In some examples, the time required for the swing-back can be predicted, and the movement can be controlled at a speed that retracts the work machine 100 within that swing-back time. For example, if the swing-back time is about 3 seconds, the maximum track speed of the machine is 2 m / s, and the unwanted movement distance is 3 meters, the processing circuit can apply half of the maximum possible track speed to correct (or compensate for) the unwanted movement. Thus, the compensating movement is maintained at a minimum speed, and smooth operation of the work machine is achieved.

[0028] On the other hand, if the unwanted movement distance is 7 meters, the processing circuit can apply the maximum possible track speed to compensate. In this example, the remaining 1 meter can be covered by further temporarily stopping the bucket before excavation to ensure time for additional chassis compensation, or the additional compensation can be provided in the next excavation cycle. If compensation is still required in the next excavation cycle, the processing circuit can perform a relaxation similar to operation 306, perform a compensation similar to operation 310, or perform a combination of both relaxation and compensation.

[0029] By performing relaxation and compensation as described herein, the processing circuit according to the exemplary aspect can avoid the detrimental effects of unwanted movement on the excavation and dumping performance of the work machine. The operator can also avoid the constant dry digging of the bucket that may occur due to errors in the excavation location.

Industrial Applicability

[0030] Generally, the work machine 100 can be configured and equipped to detect actual or imminent undesirable movement that moves the work machine 100 away from its original location and away from the location where the work machine 100 is to perform an excavation operation. The work machine 100 can include sensors for detecting horizontal movement of the machine and providing a mitigation control signal when there is a high likelihood of undesirable machine movement. This probability can be determined based on the terrain around the work machine 100, the speed of the work machine 100, the reaction forces sensed by other sensors of the work machine 100, and other factors. If the mitigation measures for preventing undesirable movement are insufficient, the compensation movement can be controlled to return the work machine 100 to its original or ideal position for excavation or other operations. The compensation movement can be executed at a timing and speed that avoids jerky movement and does not affect the excavation operation.

[0031] The above detailed description is for illustrative purposes and not limiting. Accordingly, the scope of the present disclosure should be determined with reference to the appended claims and all the scope of equivalents to which such claims are entitled.

Claims

1. An apparatus (100), comprising: a sensor circuit (158) for detecting mechanical movement or the possibility of mechanical movement of a working machine along a surface; a processing circuit (150) coupled to the sensor circuit, receiving mechanical movement information, and configured to: determine the possibility of occurrence of an undesirable movement; and provide a relaxation control signal for relaxing the undesirable movement when it is determined that the probability of occurrence of the undesirable movement exceeds a threshold.

2. The apparatus according to claim 1, wherein the probability is based on a reaction force from an operation of the working machine.

3. The apparatus according to claim 2, wherein the reaction force is estimated based on hydraulic pressure.

4. The apparatus according to claim 1, wherein the relaxation control signal comprises a control signal for damping a bucket outward from the surface.

5. The apparatus according to claim 1, wherein the relaxation control signal comprises a control signal for raising a boom of the working machine or moving a stick of the working machine outward.

6. The apparatus according to claim 1, wherein the mechanical movement includes at least one of horizontal movement, rolling movement, pitching movement, and yawing movement.

7. The processing circuit is further configured to: detect that the working machine has moved beyond a displacement of a straight line or an angle allowed by a threshold boundary from a working location; and provide a compensation control signal for controlling the working machine to move to the working location in response to the detection.

8. The processing circuit is further configured to determine an undesirable movement distance and the time until the work machine returns to the starting position, and to control a compensation movement of the work machine at a minimum speed to move by the undesirable movement distance, the apparatus according to claim 1.

9. The work machine includes an excavator, and the time until the work machine returns to the starting position includes a swing-back time of the excavator, the apparatus according to claim 8.

10. The compensation movement includes a track movement command, the apparatus according to claim 8.

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