System, method, and program

Abstract

This system specifies a virtual wall that is a plane into which a work machine provided with a traveling body having a pair of left and right traveling devices is prohibited from entering. When an operation on the traveling body is a slewing operation, the system controls the traveling speed of each of the pair of left and right traveling devices such that the outer shell of the work machine does not come into contact with the virtual wall.

Description

Systems, methods, and programs

[0001] This disclosure relates to systems, methods, and programs. This application claims priority under Japanese Patent Application No. 2024-159765, filed in Japan on 17 September 2024, the contents of which are incorporated herein by reference.

[0002] A technique is known for setting up virtual walls in space to limit the operating range of a work machine. The control device for the work machine can control the machine so that it does not exceed the virtual wall by limiting the amount of movement of the machine's actuators according to the distance between the machine and the virtual wall.

[0003] International Publication No. 2019 / 189030

[0004] Incidentally, for work machines equipped with a travel device for moving the machine, it is necessary to control the machine so that it does not cross a set virtual wall during travel. The purpose of this disclosure is to provide a system, method, and program that can control a work machine so that it does not enter a restricted area.

[0005] According to one aspect of the present disclosure, a system for controlling a work machine having a traveling body with a pair of left and right traveling devices comprises a processor. The processor identifies a virtual wall, which is a surface that the work machine cannot enter. When the operation on the traveling body is a turning operation, the processor controls the travel speed of each of the left and right traveling devices so that the virtual wall and the outer shell of the work machine do not come into contact.

[0006] According to the above embodiment, the system can be controlled to prevent work machinery from entering restricted areas.

[0007] This is a schematic diagram showing the configuration of a work machine according to the first embodiment. This is a diagram showing the drive system of the work machine according to the first embodiment. This is a schematic block diagram showing the configuration of a control device according to the first embodiment. This is a flowchart showing intervention control by the control device according to the first embodiment. This is a flowchart showing the deceleration rate calculation process by the control device according to the first embodiment. This is a diagram showing how the control device according to the first embodiment determines the distance between the control point and the virtual sphere VS and the virtual wall VW. This is a diagram showing how the control device according to the first embodiment identifies the object to be determined for interference when the traveling body of the work machine turns. This is a diagram showing how the control device according to the first embodiment determines the remaining angle from the control point and the virtual sphere VS to the virtual wall VW. This is a speed limit table showing the relationship between the distance to the control point or virtual sphere VS and the speed limit. This is a flowchart showing the deceleration rate calculation process by the control device according to the second embodiment. This is a diagram showing the relationship between the turning center and the turning radius due to operation on the traveling body. This is a diagram showing the configuration of a work system according to another embodiment.

[0008] <First Embodiment> <Configuration of the Work Machine> The embodiments will be described in detail below with reference to the drawings. Figure 1 is a schematic diagram showing the configuration of the work machine 100 according to the first embodiment. The work machine 100 according to the first embodiment is, for example, a hydraulic excavator. The work machine 100 comprises a vehicle body 110, a work machine 160, an operator's cab 180, and a control device 200. The work machine 100 according to the first embodiment is controlled to avoid contact with a virtual wall VW that is virtually generated to define a no-entry zone at the work site. As a result, the operator can operate the work machine 100 so as not to enter the no-entry zone.

[0009] The vehicle body 110 comprises a running body 120 and a turning body 140. The running body 120 supports the work machine 100 so that it can move. The running body 120 is equipped with a pair of left and right running devices. The running body 120 is equipped with tracks 121 as running devices, for example. Each track 121 has a driving motor 114 which is a drive wheel. The driving motors 114 rotate the tracks 121. By the driving motors 114 rotating the tracks 121, the work machine 100 moves or turns. The work machine 100 can change its course in an arc while moving forward or backward by rotating the left and right tracks 121 in the same direction with a difference in speed. In addition, the work machine 100 can perform a pivot turn around the track on the stationary side by rotating only one of the left and right tracks 121. Furthermore, the work machine 100 can perform a pivot turn around the center of the vehicle 120 by rotating the left and right tracks 121 in different directions at a constant speed.

[0010] The slewing body 140 is supported on the traveling body 120 so as to be able to rotate around the pivot point. The work implement 160 is operably supported on the slewing body 140. The work implement 160 is driven by hydraulics. The work implement 160 comprises a boom 161, an arm 162, and an attachment 163 which is a work tool. The attachment 163 is an example of a work tool. In the example shown in Figure 1, the attachment 163 is a bucket. The base end of the boom 161 is rotatably attached to the slewing body 140. The base end of the arm 162 is rotatably attached to the tip of the boom 161. The attachment 163 is rotatably attached to the tip of the arm 162. Here, the part of the slewing body 140 to which the work implement 160 is attached is called the front part. Also, with respect to the slewing body 140, the part opposite the front part is called the rear part, the left part is called the left part, and the right part is called the right part.

[0011] The operator's cab 180 is located at the front of the slewing body 140. Inside the operator's cab 180 are an operating device 141 for the operator to operate the work machine 100, and a monitoring device 142 which is the man-machine interface for the control device 200. The monitoring device 142 is implemented, for example, by a computer equipped with a touch panel.

[0012] The control device 200 controls the traveling body 120, the rotating body 140, and the work equipment 160 based on the operation of the operating device 141 by the operator. The control device 200 is installed, for example, inside the operator's cab 180.

[0013] 《Drive System of Work Machine 100》 Figure 2 is a diagram showing the drive system of the work machine 100 according to the first embodiment. The work machine 100 is equipped with a plurality of actuators for driving the work machine 100. Specifically, the work machine 100 is equipped with a power source 111, a hydraulic pump 112, a control valve 113, a pair of travel motors 114, a slewing motor 115, a boom cylinder 116, an arm cylinder 117, and an attachment cylinder 118.

[0014] The power source 111 drives the hydraulic pump 112. The power source 111 is, for example, an engine. The hydraulic pump 112 is driven by the power source 111 and supplies hydraulic fluid to the travel motor 114, slewing motor 115, boom cylinder 116, arm cylinder 117, and attachment cylinder 118 via the control valve 113. The control valve 113 controls the flow rate of hydraulic fluid supplied from the hydraulic pump 112 to the travel motor 114, slewing motor 115, boom cylinder 116, arm cylinder 117, and attachment cylinder 118. The travel motor 114 is driven by the hydraulic fluid supplied from the hydraulic pump 112 and rotates the track 121. The slewing motor 115 is driven by the hydraulic fluid supplied from the hydraulic pump 112 and rotates the slewing body 140 relative to the travel body 120.

[0015] The boom cylinder 116 is a hydraulic cylinder for driving the boom 161. The base end of the boom cylinder 116 is attached to the slewing body 140. The tip end of the boom cylinder 116 is attached to the boom 161. The arm cylinder 117 is a hydraulic cylinder for driving the arm 162. The base end of the arm cylinder 117 is attached to the boom 161. The tip end of the arm cylinder 117 is attached to the arm 162. The attachment cylinder 118 is a hydraulic cylinder for driving the attachment 163. The base end of the attachment cylinder 118 is attached to the arm 162. The tip end of the attachment cylinder 118 is attached to the attachment 163.

[0016] Measurement System of Work Machine 100 The work machine 100 is equipped with multiple sensors for measuring the attitude and position of the work machine 100. Specifically, the work machine 100 is equipped with an inclination meter 101, a position and orientation detector 106, a swivel angle sensor 102, a boom angle sensor 103, an arm angle sensor 104, and an attachment angle sensor 105.

[0017] The inclination meter 101 measures the attitude of the slewing body 140. The inclination meter 101 measures the inclination of the slewing body 140 with respect to the horizontal plane (e.g., roll angle, pitch angle, and yaw angle). An example of an inclination meter 101 is an IMU (Inertial Measurement Unit). In this case, the inclination meter 101 measures the acceleration and angular velocity of the slewing body 140 and calculates the inclination of the slewing body 140 with respect to the horizontal plane based on the measurement results. The inclination meter 101 is installed, for example, below the driver's cab 180. The inclination meter 101 outputs the measured attitude data of the slewing body 140 to the control device 200.

[0018] The turning angle sensor 102 measures the turning angle of the turning body 140 relative to the traveling body 120. The measured value of the turning angle sensor 102 is zero, for example, when the directions of the traveling body 120 and the turning body 140 are aligned. The turning angle sensor 102 is installed, for example, at the turning center of the turning body 140. The turning angle sensor 102 outputs the measured turning angle data to the control device 200.

[0019] The boom angle sensor 103 measures the boom angle, which is the rotation angle of the boom 161 relative to the slewing body 140. The boom angle sensor 103 may be an IMU attached to the boom 161. In this case, the boom angle sensor 103 measures the boom angle based on the inclination of the boom 161 with respect to the horizontal plane and the inclination of the slewing body measured by the inclination measuring instrument 101. The measured value of the boom angle sensor 103 is zero, for example, when the direction of the straight line passing through the base and tip of the boom 161 coincides with the front-rear direction of the slewing body 140. In other embodiments, the boom angle sensor 103 may be a stroke sensor attached to the boom cylinder 116. In other embodiments, the boom angle sensor 103 may be a rotation sensor provided on the boom pin connecting the slewing body 140 and the boom 161. The boom angle sensor 103 outputs the measured boom angle data to the control device 200.

[0020] The arm angle sensor 104 measures the arm angle, which is the rotation angle of the arm 162 relative to the boom 161. The arm angle sensor 104 may be an IMU attached to the arm 162. In this case, the arm angle sensor 104 measures the arm angle based on the inclination of the arm 162 with respect to the horizontal plane and the boom angle measured by the boom angle sensor 103. The measured value of the arm angle sensor 104 is zero, for example, when the direction of the straight line passing through the base end and tip of the arm 162 coincides with the direction of the straight line passing through the base end and tip of the boom 161. In other embodiments, the arm angle sensor 104 may be a stroke sensor attached to the arm cylinder 117 to calculate the angle. In other embodiments, the arm angle sensor 104 may be a rotation sensor provided on the arm pin connecting the boom 161 and the arm 162. The arm angle sensor 104 outputs the measured arm angle data to the control device 200.

[0021] The attachment angle sensor 105 measures the attachment angle, which is the rotation angle of the attachment 163 relative to the arm 162. The attachment angle sensor 105 may be a stroke sensor provided on the attachment cylinder 118 for driving the attachment 163. In this case, the attachment angle sensor 105 measures the attachment angle based on the stroke amount of the attachment cylinder 118. The measured value of the attachment angle sensor 105 indicates zero, for example, when the direction of the straight line passing through the base end and tip end of the attachment 163 coincides with the direction of the straight line passing through the base end and tip end of the arm 162. In other embodiments, the attachment angle sensor 105 may be a rotation sensor provided on the bucket pin connecting the arm 162 and the attachment 163. In other embodiments, the attachment angle sensor 105 may be an IMU attached to the attachment 163. The attachment angle sensor 105 outputs the measured attachment angle data to the control device 200.

[0022] The position and orientation detector 106 detects the position and orientation of the work machine 100. The position and orientation detector 106 is equipped with two receivers that receive positioning signals from artificial satellites that constitute the GNSS (Global Navigation Satellite System). An example of GNSS is GPS (Global Positioning System). The two receivers are installed at different locations on the work machine 100. Based on the positioning signals received by the receivers, the position and orientation detector 106 detects the position of a representative point of the slewing body 140 in the site coordinate system. Using the positioning signals received by the two receivers, the position and orientation detector 106 calculates the orientation of the slewing body 140 as the relationship between the installation position of one receiver and the installation position of the other receiver.

[0023] 《Configuration of Control Device 200》 Figure 3 is a schematic block diagram showing the configuration of the control device 200 according to the first embodiment. The control device 200 is a computer equipped with a processor 210, main memory 230, storage 250, and interface 270. The control device 200 is an example of a control system. The control device 200 receives measured values ​​from the tilt measuring instrument 101, slewing angle sensor 102, boom angle sensor 103, arm angle sensor 104, attachment angle sensor 105, and position and orientation detector 106.

[0024] The storage 250 is a tangible, non-temporary storage medium. Examples of the storage 250 include magnetic disks, optical disks, magneto-optical disks, and semiconductor memory. The storage 250 may be an internal medium directly connected to the bus of the control device 200, or an external medium connected to the control device 200 via the interface 270 or a communication line. The storage 250 stores a control program for controlling the work machine 100.

[0025] The control program may be for implementing a part of the functions to be performed by the control device 200. For example, the control program may perform its functions in combination with other programs already stored in the storage 250, or in combination with other programs implemented in other devices. In other embodiments, the control device 200 may include a custom LSI (Large Scale Integrated Circuit) such as a PLD (Programmable Logic Device) in addition to, or instead of, the above configuration. Examples of PLDs include PAL (Programmable Array Logic), GAL (Generic Array Logic), CPLD (Complex Programmable Logic Device), and FPGA (Field Programmable Gate Array). In this case, some or all of the functions implemented by the processor may be implemented by the integrated circuit.

[0026] The storage 250 records geometric data representing the dimensions and center of gravity of the traveling body 120, the slewing body 140, the boom 161, the arm 162, and the attachment 163. Geometric data is data representing the position of an object in a predetermined coordinate system.

[0027] Parameter data for each virtual wall VW is recorded in the storage 250. In the first embodiment, the virtual wall VW is installed perpendicular to the ground surface. The parameters of the virtual wall VW may be the positions (latitude and longitude) of two points in the field coordinate system. In this case, the plane formed between the edges extending vertically from the two specified points is identified as the virtual wall VW. In other embodiments, however, the parameters of the virtual wall VW may be represented by the three dimensions of one point in the field coordinate system and the orientation of the wall surface.

[0028] The storage 250 stores a travel speed table, which is a function showing the relationship between the distance to the virtual wall VW and the speed limit. The speed limit is the speed at which the work machine 100 can stop without exceeding the virtual wall VW when traveling at that speed. The travel speed table is a function in which the speed limit decreases as the distance to the virtual wall VW decreases.

[0029] 《Software Configuration》 The processor 210, by executing a control program, includes an operation signal receiving unit 211, an input unit 212, a display control unit 213, a measured value receiving unit 214, a position identification unit 215, an intervention determination unit 218, an intervention control unit 219, and a control signal output unit 220.

[0030] The operation signal receiving unit 211 receives operation signals from the operation device 141 indicating the operating direction and amount of each actuator. The display control unit 213 outputs screen data to be displayed on the monitor device 142 to the monitor device 142. The measurement value receiving unit 214 receives measurement values ​​from the inclination measuring instrument 101, slewing angle sensor 102, boom angle sensor 103, arm angle sensor 104, attachment angle sensor 105, and position and orientation detector 106.

[0031] The positioning unit 215 identifies the position of the outer shell of the work machine 100 in the vehicle coordinate system. The outer shell of the work machine 100 is the external shape of the work machine 100. The outer shell of the work machine 100 is defined, for example, by the shapes that form the external shapes of the slewing body 140 and the work machine 160. Specifically, the positioning unit 215 identifies the positions of multiple points (control points) on the outer shell of the work machine 100 in the vehicle coordinate system based on various measurement values ​​received by the measurement value receiving unit 214 and geometry data recorded in the storage 250. The control points identified by the positioning unit 215 include the tip of the attachment 163 (e.g., the cutting edge of the bucket), the end of the arm 162 on the attachment 163 side (arm top), the end of the arm 162 on the boom 161 side (arm bottom), the point behind the counterweight of the slewing body 140, and the end of the track 121. The vehicle body coordinate system is a Cartesian coordinate system with the origin at a representative point of the rotating body 140 (for example, a point passing through the center of rotation). The calculations of the position identification unit 215 will be described later. Note that the points identified by the position identification unit 215 are not limited to these. In the first embodiment, the shapes of the outer shells of the attachment 163, arm top, and arm bottom are simulated by a virtual sphere VS. The virtual sphere VS is a virtual sphere that encloses the outer shell of a target part whose shape changes depending on the angle between two objects, such as the joint portion of the work machine 160. By considering the surface of the virtual sphere VS as the outer shell of the target part, the control device 200 can determine the possibility of contact between the virtual wall VW and the outer shell while reducing the amount of computation.

[0032] The intervention determination unit 218 determines whether or not to limit the speed of the traveling body 120 based on the positional relationship between the control point identified by the position identification unit 215 and the virtual wall VW. Hereinafter, the control device 200 limiting the speed of the traveling body 120 is also referred to as intervention control. Specifically, the intervention determination unit 218 determines the minimum distance between the virtual wall VW and the work machine 100, and if the minimum distance is less than or equal to a predetermined distance, it determines to perform intervention control on the traveling body 120. In addition to intervention control on the traveling body 120, the control device 200 in other embodiments may also perform intervention control on the slewing body 140 and the work machine 160.

[0033] When the intervention control unit 219 determines that intervention control is to be performed by the intervention determination unit 218, it controls the operation amount of the actuator to be intervened among the operation signals received by the operation signal reception unit 211. The control signal output unit 220 outputs the operation signal received by the operation signal reception unit 211 or the operation signal controlled by the intervention determination unit 218 to the control valve 113.

[0034] 《Calculation of the Position Specifying Unit 215》 Here, a method for specifying the position of a point on the outer shell of the work machine 100 by the position specifying unit 215 will be described. The position specifying unit 215 specifies the position of a point on the outer shell based on various measurement values received by the measurement value reception unit 214 and the geometry data recorded in the storage 250. The storage 250 records geometry data representing the dimensions of the revolving body 140, the boom 161, the arm 162, and the attachment 163.

[0035] The geometry data of the traveling body 120 is the position (x ｔｂ , y ｔｂ , z ｔｂ ) of a point on the outer shell of the traveling body 120 in the traveling body coordinate system, which is a local coordinate system. As points on the outer shell of the traveling body 120, for example, the outer points at the front end and the rear end of the crawler 121 can be mentioned. The traveling body coordinate system is an X ｔｂ axis extending in the front-rear direction, a Y ｔｂ axis extending in the left-right direction, and a Z ｔｂ axis extending in the up-down direction, with the center of rotation of the revolving body 140 as a reference. Note that the up-down direction of the revolving body 140 does not necessarily coincide with the vertical direction.

[0036] The geometry data of the revolving body 140 is the position (x ｂｍ , y ｂｍ , z ｂｍ ) of the boom pin that supports the boom 161 of the revolving body 140 and the position (x ｓｐ , y ｓｐ , z ｓｐ ) of a point on the outer shell of the revolving body 140 in the vehicle body coordinate system, which is a local coordinate system. As points on the outer shell of the revolving body 140, for example, points that are likely to come into contact with the wall surface due to turning, such as the protruding points of the counterweight, can be mentioned. The vehicle body coordinate system is an X extending in the front-rear direction with the center of rotation of the revolving body 140 as a referenceｓｂ Axis, Y extending in the left-right direction ｓｂ Axis, Z extending in the vertical direction ｓｂ This is a coordinate system composed of axes. Note that the vertical direction of the rotating body 140 does not necessarily coincide with the vertical direction.

[0037] The geometry data for boom 161 is the position of the arm pin in the boom coordinate system, which is the local coordinate system (x ａｍ , y ａｍ , z ａｍ The boom coordinate system is defined as the X-axis extending longitudinally, with the position of the pin connecting the boom 161 and the slewing body 140 as the reference point. ｂｍ The Y extends in the direction in which the axis and pin extend. ｂｍ axis, X ｂｍ Axis and Y ｂｍ Z perpendicular to the axis ｂｍ It is a coordinate system composed of axes.

[0038] The geometry data of arm 162 is the position of the bucket pin in the local coordinate system, the arm coordinate system (x ａｔ , y ａｔ , z ａｔ The arm coordinate system is based on the position of the pin connecting the arm 162 and the boom 161, with the X extending in the longitudinal direction. ａｍ The Y extends in the direction in which the axis and pin extend. ａｍ axis, X ａｍ Axis and Y ａｍ Z perpendicular to the axis ａｍ This is a coordinate system composed of axes. The geometric data of the arm 162 also includes information on the center points and radii of virtual spheres VS1 and VS2 that simulate the outer shells of the arm bottom and arm top. Virtual sphere VS1, representing the arm bottom, is centered on the arm pin and encloses at least the base end of the arm 162. Virtual sphere VS2, representing the arm top, is centered on the bucket pin and encloses at least the tip of the arm 162. The arm bottom and arm top are points on the outer shell of the work machine 100.

[0039] The geometric data of attachment 163 includes information on the center point and radius of a virtual sphere VS3 that simulates the outer shell of attachment 163. The virtual sphere VS3 representing attachment 163 encompasses the entire attachment 163. The center point of the virtual sphere VS3 may be the midpoint of the line segment connecting the midpoint of the rotation axis of attachment 163 and the midpoint of the tip of attachment 163. In other embodiments, the center point of the virtual sphere VS3 may be the geometric center of attachment 163, or it may be the point at which the virtual sphere VS encompassing attachment 163 becomes the smallest enclosing sphere. The geometric data of attachment 163 includes the position (x) of the center point of the virtual sphere VS3 in the attachment coordinate system, which is the local coordinate system. ｃｐ , y ｃｐ , z ｃｐ The attachment coordinate system is based on the position of the pin connecting the attachment 163 and the arm 162, with the X extending in the direction of the tip. ａｔ The Y extends in the direction in which the axis and pin extend. ａｔ axis, X ａｔ Axis and Y ａｔ Z perpendicular to the axis ａｔ It is a coordinate system composed of axes.

[0040] The positioning unit 215 is determined by the rotation angle θ received by the measurement value receiving unit 214. ｓｂ Based on the measured values ​​and the geometry data of the vehicle 120, the vehicle-to-vehicle transformation matrix T for converting from the vehicle coordinate system to the vehicle coordinate system is calculated using the following equation (1). ｔｂ ｓｂ Generates the following: Vehicle-vehicle transformation matrix T ｔｂ ｓｂ is, Z ｔｂ Rotation angle θ around the axis ｓｂ This is a matrix that rotates only in the opposite direction. The position identification unit 215 uses the position of the outer shell of the vehicle 120 in the vehicle coordinate system indicated by the geometry data of the vehicle 120 and the vehicle-vehicle transformation matrix T ｔｂ ｓｂ By calculating the product of these two values, the position of the outer shell of the vehicle body 120 in the vehicle body coordinate system is determined.

[0041]

[0042] The positioning unit 215 receives the boom angle θ from the measurement value receiving unit 214. ｂｍ Based on the measured values ​​and the geometry data of the rotating body 140, the boom-to-vehicle body transformation matrix T for converting from the boom coordinate system to the vehicle body coordinate system is calculated using the following equation (2). ｂｍ ｓｂ Generates the boom-body transformation matrix T. ｂｍ ｓｂ Y ｂｍ Boom angle θ around the axis ｂｍ Rotate by only that much, and the deviation (x) between the origin of the vehicle coordinate system and the origin of the boom coordinate system ｂｍ , y ｂｍ , z ｂｍ This is a matrix that translates by only a certain amount. The position identification unit 215 uses the position of the arm pin in the boom coordinate system indicated by the geometry data of the boom 161 and the boom-vehicle body transformation matrix T ｂｍ ｓｂ By calculating the product of these two values, we can determine the position of the arm pin in the vehicle coordinate system.

[0043]

[0044] The positioning unit 215 receives the arm angle θ from the measurement value receiving unit 214. ａｍ Based on the measured values ​​and the geometry data of boom 161, the arm-boom transformation matrix T for converting from the arm coordinate system to the boom coordinate system is calculated using the following equation (3). ａｍ ｂｍ Generates the arm-boom transformation matrix T. ａｍ ｂｍ Y ａｍ Arm angle θ around the axis ａｍ Rotate by only that much, and the deviation (x) between the origin of the boom coordinate system and the origin of the arm coordinate system ａｍ , y ａｍ , z ａｍ This is a matrix that translates by only ). Also, the position determination unit 215 is the boom-body transformation matrix T ｂｍ ｓｂ and the arm-boom transformation matrix T ａｍ ｂｍ By calculating the product of these, we obtain the arm-to-vehicle transformation matrix T for transforming from the arm coordinate system to the vehicle coordinate system. ａｍ ｓｂGenerate it. Also, the position specifying unit 215 determines the position of the bucket pin in the arm coordinate system indicated by the geometry data of the arm 162 and the product with the arm-body transformation matrix T ａｍ ｓｂ to obtain the position of the bucket pin in the vehicle body coordinate system.

[0045]

[0046] The position specifying unit 215 generates an attachment-arm transformation matrix T ａｔ for converting from the attachment coordinate system to the arm coordinate system according to the following formula (4) based on the measured value of the attachment angle θ ａｔ ａｍ received by the measurement value receiving unit 214 and the geometry data of the arm 162. The attachment-arm transformation matrix T ａｔ ａｍ is a matrix that rotates by the attachment angle θ ａｔ around the Y ａｔ axis and translates by the deviation (x ａｔ , y ａｔ , z ａｔ ) between the origin of the arm coordinate system and the origin of the attachment coordinate system. Also, the position specifying unit 215 obtains the product of the arm-body transformation matrix T ａｍ ｓｂ and the attachment-arm transformation matrix T ａｔ ａｍ to generate an attachment-body transformation matrix T ａｔ ｓｂ for converting from the attachment coordinate system to the vehicle body coordinate system.

[0047]

[0048] The position specifying unit 215 obtains the position of the center point of the virtual sphere VS3 of the attachment 163 in the vehicle body coordinate system by obtaining the product of the position of the tip in the attachment coordinate system indicated by the geometry data of the attachment 163 and the attachment-body transformation matrix T ａｔ ｓｂ .

[0049] 《Control Method for the Work Machine 100》 The control method for the work machine 100 according to the first embodiment will be described below. When the control device 200 is started up, it reads the parameters, geometry data, and speed limit table of the virtual wall VW recorded in the storage 250 into the main memory 230.

[0050] Figure 4 is a flowchart showing the intervention control by the control device 200 according to the first embodiment. The control device 200 starts the control described below.

[0051] The operation signal receiving unit 211 receives operation signals from the operation device 141 for the left and right pair of traveling devices of the traveling body 120 (step S1). The measurement value receiving unit 214 receives measurement values ​​from the tilt measuring instrument 101, the slewing angle sensor 102, the boom angle sensor 103, the arm angle sensor 104, the attachment angle sensor 105, and the position and orientation detector 106 (step S2).

[0052] The intervention control unit 219 determines the position and orientation of the slewing body 140 based on the measured values ​​received in step S2. The intervention control unit 219 identifies the position of the virtual wall VW in the vehicle coordinate system based on the parameters of the virtual wall VW and the position and orientation of the slewing body 140 (step S3). The position identification unit 215 identifies the positions of the control points of the work machine 100 and the virtual sphere VS in the vehicle coordinate system based on the measured values ​​received in step S2 (step S4).

[0053] The intervention determination unit 218 selects each virtual wall VW whose position was identified in step S3 (step S5) and performs the following deceleration rate calculation process. The deceleration rate is a value between 0 and 1 that is multiplied by the command speed of the track 121 by the operating device for intervention control.

[0054] Figure 5 is a flowchart showing the deceleration rate calculation process by the control device 200 according to the first embodiment. The intervention determination unit 218 determines whether the operation on the vehicle 120 is a straight-ahead operation, a turning operation, or a stop operation based on the operation signal received in step S1 (step S21). The intervention determination unit 218 determines that the operation on the vehicle 120 is a straight-ahead operation if the operating directions of the right track 121 and the left track 121 coincide and the difference in the amount of operation between the right track 121 and the left track 121 is less than or equal to a predetermined threshold. The intervention determination unit 218 determines that the operation on the vehicle 120 is a turning operation if the operating directions of the right track 121 and the left track 121 do not coincide, or if the difference in the amount of operation between the right track 121 and the left track 121 exceeds a predetermined threshold. The intervention determination unit 218 determines that the operation on the vehicle 120 is a stopping operation if the amount of operation of both the right track 121 and the left track 121 falls below a predetermined threshold.

[0055] If the operation on the vehicle 120 is determined to be a straight-line operation (step S21: straight-line), the intervention determination unit 218 determines whether the direction of travel of the vehicle 120 is towards or away from the virtual wall VW selected in step S5 (step S22).

[0056] If the operation performed on the vehicle 120 is a straight-line operation and the vehicle 120 is determined to be moving away from the virtual wall VW (step S22: moving away), or if the operation performed on the vehicle 120 is determined to be a stop operation (step S21: stopping), the intervention determination unit 218 determines the deceleration rate to be 1 (step S23).

[0057] When it is determined that the traveling body 120 is moving in a direction approaching the virtual wall VW (step S22: approaching), the intervention determination unit 218 calculates the distances between the virtual wall VW selected in step S5 and the control point and the virtual sphere VS specified in step S4, respectively (step S24). FIG. 6 is a diagram showing how to obtain the distances between the control point and the virtual sphere VS and the virtual wall VW by the control device 200 according to the first embodiment. The intervention determination unit 218 obtains the length of a line segment parallel to the direction in which the traveling body 120 faces connecting the control point or the virtual sphere VS of the working machine 100 and the virtual wall VW as the distance between the control point or the virtual sphere VS and the virtual wall VW. Note that when the wall surface of the virtual wall VW and the direction in which the traveling body 120 faces are parallel, the distance cannot be obtained. In this case, the intervention determination unit 218 may set the distance between the control point or the virtual sphere VS and the virtual wall VW as a distance at which the speed is not restricted in the speed limit table. The intervention determination unit 218 specifies the control point or the virtual sphere VS with the shortest distance obtained in step S24 (step S25).

[0058] When it is determined in step S21 that the operation on the traveling body 120 is a turning operation (step S21: turning), the intervention determination unit 218 specifies the turning direction of the traveling body 120 based on the operation signal received in step S1 (step S26). Based on the turning direction of the traveling body 120 specified in step S26, the intervention determination unit 218 specifies, as interference determination targets, the control point and the virtual sphere VS approaching the virtual wall VW among the control point and the virtual sphere VS specified in step S4 (step S27). FIG. 7 is a diagram showing a method for specifying interference determination targets when the traveling body 120 of the working machine 100 according to the first embodiment turns. The intervention determination unit 218 sets a determination plane that is orthogonal to the X ｓｂ -Y ｓｂ plane of the vehicle body coordinate system and passes through the midpoint M of the pair of left and right crawlers 121. The midpoint M is the intersection of a line connecting the right front end of the right crawler 121 and the left rear end of the left crawler 121 and a line connecting the right rear end of the right crawler 121 and the left front end of the left crawler 121 when the traveling body 120 is viewed from the vertical direction. Note that the midpoint M may be a point passing through the turning center of the turning body 140.

[0059] As shown in Figure 7, if the intervention determination unit 218 determines, for example, in step S26 that the turning direction of the vehicle 120 is to the left, it decides to make the point located to the right of the determination plane toward the virtual wall VW and the virtual sphere VS whose center point is also to the right of the determination plane the targets for interference determination. Also, if the intervention determination unit 218 determines, for example, in step S26 that the turning direction of the vehicle 120 is to the right, it decides to make the point located to the left of the determination plane toward the virtual wall VW and the virtual sphere VS whose center point is also to the left of the determination plane the targets for interference determination. In other words, of the control points and virtual spheres VS identified in step S4, the intervention determination unit 218 makes the control points and virtual spheres VS on the side that rotates toward the virtual wall VW due to the turning of the vehicle 120 the targets for interference determination. On the other hand, the intervention determination unit 218 does not consider the control points and virtual spheres VS identified in step S4 that rotate in a direction away from the virtual wall VW due to the turning of the vehicle 120 as targets for interference determination.

[0060] In step S27, once the control points and virtual spheres VS to be subject to interference determination are determined, the intervention determination unit 218 determines the remaining angle until the working machine 100 rotates and contacts the virtual wall VW selected in step S5 for each of the control points and virtual spheres VS that were subject to interference determination in step S27 (step S28). Figure 8 shows how the control device 200 according to the first embodiment determines the remaining angle from the control points and virtual spheres VS to the virtual wall VW. The intervention determination unit 218 determines the remaining angle for each control point using the following method: It determines whether a determination circle AC, centered at the midpoint M of the left and right pair of tracks 121 and with the distance from the midpoint M to the control point as its radius, interferes with the virtual wall VW. If the determination circle AC does not interfere with the virtual wall VW, the intervention determination unit 218 determines that the control point will not contact the virtual wall VW due to rotation. If the determination circle AC interferes with the virtual wall VW, the intervention determination unit 218 identifies the point on the base end side in the turning direction identified in step S26 as the determination point AP among the intersection points of the determination circle AC and the virtual wall VW. The intervention determination unit 218 identifies the angle between the straight line connecting the midpoint M and the control point and the straight line connecting the midpoint M and the determination point AP as the remaining angle. The intervention determination unit 218 determines the remaining angle for each control sphere VS using the following method. The intervention determination unit 218 determines whether the determination circle AC, centered at the midpoint M of the track 121 and with a radius equal to the distance from the midpoint M to the center point of the control sphere VS, interferes with the determination wall AW, which is brought closer to the work machine 100 side by an amount equivalent to the radius of the control sphere VS. If the determination circle AC does not interfere with the determination wall AW, the intervention determination unit 218 determines that the virtual sphere VS will not come into contact with the virtual wall VW due to turning. If the determination circle AC interferes with the determination wall AW, the intervention determination unit 218 identifies the point on the base end side of the rotation direction identified in step S26 as the determination point AP among the intersection points of the determination circle AC and the determination wall AW. The intervention determination unit 218 identifies the angle between the line connecting the midpoint M and the center of the control sphere VS and the line connecting the midpoint M and the determination point AP as the remaining angle. For control points or virtual spheres VS that the intervention determination unit 218 determines do not come into contact with the virtual wall VW, it sets the remaining angle to a sufficiently large value (for example, 360 degrees) that does not contribute to intervention control.

[0061] The intervention determination unit 218 estimates a circle with its center at the midpoint M of the pair of left and right tracks 121, and its diameter being the distance between the centers of the left and right tracks in the width direction. The unit determines the arc length (arc length) of the estimated circle with the remaining angle related to the control point or virtual sphere VS identified in step S28 as its central angle, and determines the shortest of these arcs as the distance to the virtual wall VW (step S29).

[0062] Figure 9 is a speed limit table showing the relationship between the distance to the control point or virtual sphere VS and the speed limit. Based on the speed limit table, the intervention control unit 219 determines the speed limit from the distance to the control point or virtual sphere VS identified in step S25 or step S29 (step S30). The intervention control unit 219 determines the deceleration rate of the tracks 121 based on the command speeds for each of the left and right tracks 121 indicated by the operation signal received in step S1 and the speed limit determined in step S30 (step S31). Specifically, the intervention control unit 219 calculates the deceleration rate by dividing the speed limit by the higher of the command speeds for each of the left and right tracks 121 indicated by the operation variable, which is the speed at which the vehicle approaches the virtual wall VW. In step S6 of the flowchart shown in Figure 4, the intervention control unit 219 executes the deceleration rate calculation process from steps S21 to S31 described above.

[0063] The control device 200 performs a deceleration rate calculation process for each virtual wall VW, and once it has calculated the deceleration rate for each virtual wall VW, the intervention control unit 219 identifies the smallest of the calculated deceleration rates (step S7). The intervention control unit 219 calculates the target speed for each of the left and right pairs of tracks 121 by multiplying the command speed for each of the left and right pairs of tracks indicated by the operation signal by the deceleration rate identified in step S7 (step S8). As a result, the ratio of the travel speed indicated by the operation signal for the right track 121 to the target speed for the right track 121 is equal to the ratio of the travel speed indicated by the operation signal for the left track 121 to the target speed for the left track 121. Therefore, the control device 200 can rotate the left and right pairs of tracks 121 at the same ratio as the ratio of the operation amounts indicated by the operation signals for the left and right pairs of tracks 121.

[0064] The control signal output unit 220 generates a control signal based on the target speed calculated in step S8 and outputs it to the control valve 113 (step S9).

[0065] 《Operation and Effects》 As described above, the control device 200 according to the first embodiment controls the work machine 100 in the following procedure. The control device 200 identifies a virtual wall VW that is virtually generated to define the no-entry zone for the work machine 100. The control device 200 controls the travel speed of the work machine 100 based on the remaining angle until the outer shell of the work machine 100 touches the virtual wall VW. That is, when the operation on the traveling body 120 is a turning operation, the control device 200 controls the travel speed of each of the left and right pairs of tracks 121 so that the virtual wall VW and the outer shell of the work machine 100 do not come into contact. This makes it possible to control the work machine 100 so that it does not enter the no-entry zone.

[0066] Furthermore, the control device 200 according to the first embodiment controls the travel speed based on the remaining angle when the amount of operation of the left and right pair of tracks 121 is different. When the operating directions of the left and right pair of tracks 121 are different from each other, or when the amount of operation of the left and right pair of tracks 121 is different, the work machine 100 turns. Therefore, according to the first embodiment, when the work machine 100 turns by traveling, the travel speed can be appropriately controlled according to the remaining angle of the turn.

[0067] Furthermore, in the control device 200 according to the first embodiment, when the amount of operation of the left and right pair of tracks 121 is different, the control device 200 identifies the portion of the outer shell of the work machine 100 that approaches the virtual wall VW, and determines the travel speed based on the remaining angle from the identified portion to the virtual wall VW. The portion of the work machine 100 that is on the opposite side of the turning direction has a sufficiently long distance before it comes into contact with the virtual wall VW due to the turning. Therefore, the control device according to the first embodiment can reduce the amount of computation required for intervention control. In addition, in the control device 200 according to other embodiments, the calculation in step S27 of Figure 5 may be omitted, and the remaining angle may be calculated for all control points and virtual sphere VS.

[0068] <Second Embodiment> In the first embodiment, the control device 200 performs intervention control assuming that the turning center due to travel is the midpoint M of the left and right pair of tracks 121. On the other hand, the turning center due to actual travel changes depending on the difference in travel speed of the left and right tracks 121. In the second embodiment, the control device 200 estimates the turning center due to travel and performs intervention control based on the turning center. The configuration of the work machine 100 in the second embodiment is the same as in the first embodiment. In the work machine 100 in the second embodiment, the procedure for calculating the reduction rate by the control device 200 differs from that of the first embodiment.

[0069] Figure 10 is a flowchart showing the deceleration rate calculation process by the control device 200 according to the second embodiment. The intervention determination unit 218 determines whether the operation on the vehicle 120 is a stop operation based on the operation signal received in step S1 (step S41). If it is determined that the operation on the vehicle 120 is a stop operation (step S41: YES), the intervention determination unit 218 determines the deceleration rate to be 1 (step S42).

[0070] Figure 11 shows the relationship between the turning center and turning radius based on the operation performed on the vehicle 120. When the operation performed on the vehicle 120 is not a stop operation (step S41: NO), that is, when the operation performed on the vehicle 120 is a straight-ahead operation or a turning operation, the intervention determination unit 218 estimates the turning center and turning radius of the vehicle 120 from the measured speed values ​​of the left and right tracks 121 received in step S2 (step S43). When the vehicle 120 is moving in a straight line, there is no difference in the measured speed values, so the turning center can be said to be at infinity relative to the work machine. However, since it is not possible to set the turning radius to infinity in the calculation by the control device 200, the control device 200 sets an upper limit for the turning radius in advance. As shown in Figure 11, the turning center and turning radius change according to the operation performed on the vehicle 120. When the difference in the measured speed values ​​of the left and right tracks 121 is small, the turning radius becomes larger. In other words, it is estimated that the turning center exists at a point far from the vehicle 120. The turning radius is the average distance from the estimated turning center to the center of the width of each track on the left and right tracks 121. Next, the intervention determination unit 218 determines the turning direction of the vehicle 120 based on the operation signal received in step S1 (step S44).

[0071] Based on the turning center identified in step S43 and the turning direction of the vehicle body 120 identified in step S44, the intervention determination unit 218 identifies the control point and virtual sphere VS that are approaching the virtual wall VW from among the control point and virtual sphere VS identified in step S44 as targets for interference determination (step S45). The intervention determination unit 218 then determines the X coordinate system of the vehicle body coordinate system and the virtual wall VW selected in step S5. ｓｂ -Y ｓｂA determination plane is set that is perpendicular to the plane and passes through the turning center estimated in step S43, and the interference determination targets are determined based on this determination plane. If the intervention determination unit 218 determines that the turning direction of the vehicle 120 is to the left, it decides to make the points located to the right of the determination plane toward the virtual wall VW and the virtual sphere VS whose center point is to the right of the determination plane the targets of interference determination. Also, if the intervention determination unit 218 determines that the turning direction of the vehicle 120 is to the right, it decides to make the points located to the left of the determination plane toward the virtual wall VW and the virtual sphere VS whose center point is to the left of the determination plane the targets of interference determination.Therefore, if the operation on the vehicle 120 is an operation that moves it away from the virtual wall VW, not all control points and virtual sphere VS may be the targets of interference determination.In this case, the intervention determination unit 218 determines the deceleration rate to 1 in step S50 described later.

[0072] In step S45, once the control points and virtual spheres VS to be subjected to interference determination are determined, the intervention determination unit 218 determines the remaining angle until the working machine 100 rotates and contacts the virtual wall VW selected in step S5 (step S46).

[0073] The intervention determination unit 218 determines the remaining angle for each control point using the following method. The intervention determination unit 218 determines whether or not the determination circle AC, whose radius is the distance from the rotation center to the control point estimated in step S43, interferes with the virtual wall VW. If the determination circle AC does not interfere with the virtual wall VW, the intervention determination unit 218 determines that the control point will not come into contact with the virtual wall VW due to rotation. If the determination circle AC does interfere with the virtual wall VW, the intervention determination unit 218 identifies the point on the base end side of the rotation direction identified in step S44 as the determination point AP among the intersection points of the determination circle AC and the virtual wall VW. The intervention determination unit 218 identifies the angle between the straight line connecting the rotation center and the control point estimated in step S43 and the straight line connecting the rotation center and the determination point AP as the remaining angle. The intervention determination unit 218 determines the remaining angle for each control sphere VS using the following method. The intervention determination unit 218 determines whether the determination circle AC, whose radius is the distance from the pivot center estimated in step S43 to the center point of the control sphere VS, interferes with the determination wall AW, which is the virtual wall VW brought closer to the work machine 100 side by a radius equivalent to that of the control sphere VS. If the determination circle AC does not interfere with the determination wall AW, the intervention determination unit 218 determines that the virtual sphere VS will not come into contact with the virtual wall VW due to its rotation. If the determination circle AC does interfere with the determination wall AW, the intervention determination unit 218 identifies the determination circle as the determination point AP. The intervention determination unit 218 identifies the angle between the straight line connecting the pivot center estimated in step S43 and the center of the control sphere VS and the straight line connecting the pivot center and the determination point AP as the remaining angle.

[0074] The intervention determination unit 218 identifies the control point or virtual sphere VS with the smallest remaining angle determined in step S46 (step S47). The intervention determination unit 218 determines the length of an arc having the turning radius estimated in step S43 and with the remaining angle related to the control point or virtual sphere VS identified in step S47 as its central angle (step S48).

[0075] The intervention control unit 219 determines the speed limit from the arc length obtained in step 48 based on the speed limit table (step S49). The intervention control unit 219 determines the deceleration rate of the tracks 121 based on the command speeds for each of the left and right tracks 121 indicated by the operation signal received in step S1 and the speed limit determined in step S49 (step S50). Specifically, the intervention control unit 219 calculates the deceleration rate by dividing the speed limit by the higher of the command speeds for each of the left and right tracks 121 indicated by the operation amount, which is the speed at which the vehicle approaches the virtual wall VW.

[0076] 《Operation and Effects》 As described above, the control device 200 according to the second embodiment determines the position of the turning center and the turning radius based on the speed of each track 121, and determines the deceleration rate based on these. As a result, the control device 200 according to the second embodiment can perform intervention control with greater accuracy compared to the first embodiment. Furthermore, the control device 200 according to the second embodiment performs intervention control by calculating the deceleration rate based on the arc length, regardless of whether it is a turning operation or a straight-line operation. As a result, the control device 200 can achieve intervention control with simple control. On the other hand, the control device 200 according to the other embodiment may perform the calculation of the deceleration rate based on the arc length only when it is a turning operation, and perform the same calculation as the first embodiment when it is a straight-line operation.

[0077] <Other Embodiments> Although one embodiment has been described in detail above with reference to the drawings, the specific configuration is not limited to that described above, and various design changes can be made. That is, in other embodiments, the order of the above-described processes may be changed as appropriate. Also, some processes may be executed in parallel. The control device 200 according to the above-described embodiment may be composed of a single computer, or the configuration of the control device 200 may be divided among multiple computers, and the multiple computers may cooperate with each other to function as the control device 200. In this case, some of the computers constituting the control device 200 may be mounted inside the work machine 100, and the other computers may be provided outside the work machine 100.

[0078] The work machine 100 according to the above embodiment is equipped with tracks 121 as a running device, but is not limited thereto. For example, in other embodiments, the work machine 100 may be equipped with wheels as a running device. The wheels may also be steering wheels that can be steered by a steering mechanism. If the work machine 100 is equipped with steering wheels, the control device 200 can determine whether to perform a turning operation based on the steering angle.

[0079] The control device 200 according to the above embodiment identifies the operation of the vehicle 120 based on an operation signal, but is not limited to this. For example, the control device 200 according to another embodiment may identify the operation of the vehicle 120 from a measured value of the rotational speed of the track 121.

[0080] The virtual wall VW according to the above-described embodiment is recorded in advance in the storage 250 of the control device 200, but is not limited to this. For example, the virtual wall VW according to another embodiment may be calculated based on the position of other work machines 100 so as not to interfere with other work machines 100. Also, the virtual wall VW according to the above-described embodiment is represented in the field coordinate system, but the virtual wall VW according to another embodiment may be represented in the vehicle body coordinate system.

[0081] The work machine 100 according to the above-described embodiment is operated by an operator seated in the driver's cab 180, but the work machine 100 according to other embodiments is not limited to this. Figure 12 is a diagram showing the configuration of a work system according to another embodiment. The work machine 100 according to other embodiments may be operated by a remote control device 500 as shown in Figure 12. The remotely controlled work machine 100, in addition to the configuration of the above-described embodiment, further includes an imaging device 119, and the control device 200 transmits images captured by the imaging device 119 to the remote control device 500 in real time. The remote control device 500 includes a driver's seat 510, a display 520, an operating device 530, and a remote control server 540. The remote control server 540 displays the images received from the work machine 100 on the display 520. This allows the operator to recognize the situation around the remote work machine 100. The remote control server 540 also transmits operation signals from the operator to the operating device 530 to the work machine 100 via the network. The remote control server 540 performs at least some of the functions of the control device 200 according to the above-described embodiment. In other words, in a work system equipped with a remote control server 540, the control device 200 and the remote control server 540 constitute the work system. In other embodiments, the work machine 100 may operate autonomously. For example, when construction data from the site is input to the control device 200 via a communication line, the control device 200 determines an operation plan for the work machine 100 based on the construction data and its own position and orientation at the site, and controls the work machine 100. At this time, the control device 200 determines the travel speed so that the virtual wall VW and the work machine 100 do not come into contact. In this way, the control device 200 can control the work machine 100 so that it does not enter a restricted area.

[0082] The work machine 160 according to the above embodiment is equipped with a bucket as an attachment 163, but is not limited to this. For example, the work machine 160 according to other embodiments may be equipped with other work tools such as a breaker or a grapple instead of a bucket. In addition, the attachment 163 according to other embodiments may be attached to the tip of the arm 162 via a tilt attachment or a tilt-rotate attachment.

[0083] The control device 200 according to the above embodiment simulates the outer shell of the arm bottom, arm top, and attachment 163 with a virtual sphere VS to determine the distance to the virtual wall VW, but is not limited to this. For example, the work machine 160 according to another embodiment may determine the position of the outer shell using geometric data that indicates the positions of multiple points (control points) on the outer shell of the arm bottom, arm top, and attachment 163.

[0084] The intervention determination unit 218 according to the above embodiment determines the distance from the virtual wall VW to the control point or virtual sphere VS that has the shortest arc length. However, it is not limited to this. For example, the intervention determination unit 218 according to another embodiment may use the distance to the virtual wall VW to the control point or virtual sphere VS with the smallest remaining angle.

[0085] According to the above embodiment, the system can be controlled to prevent work machinery from entering restricted areas.

[0086] 100...Work machine 101...Incline measuring instrument 102...Slewing angle sensor 103...Boom angle sensor 104...Arm angle sensor 105...Attachment angle sensor 106...Position and orientation detector 111...Power source 112...Hydraulic pump 113...Control valve 114...Travel motor 115...Slewing motor 116...Boom cylinder 117...Arm cylinder 118...Attachment cylinder 119...Imaging device 120...Travel body 121...Track 140...Slewing body 141...Operating device 142...Monitor device 160...Work machine 161...Boom 162...Arm 163...Attachment 180...Operator's cab 200...Control device 210...Processor 211...Operation signal receiving unit 212...Input unit 213...Display control unit 214...Measurement value receiving unit 215...Location identification unit 218...Intervention determination unit 219...Intervention control unit 220...Control signal output unit 230...Main memory 250...Storage 270...Interface 500...Remote control device 510...Driver's seat 520...Display 530...Operating device 540...Remote control server VW...Virtual wall

Claims

1. A system for controlling a work machine having a traveling body equipped with a pair of left and right traveling devices, comprising a processor, the processor identifying a virtual wall which is a surface that the work machine cannot enter, and, when the operation on the traveling body is a turning operation, controlling the travel speed of each of the left and right traveling devices so that the virtual wall and the outer shell of the work machine do not come into contact.

2. The system according to claim 1, wherein the processor controls the travel speed based on at least one of the operating direction for each of the left and right travel devices and the amount of operation for each of the left and right travel devices.

3. The system according to claim 2, wherein the processor determines the direction of rotation of the work machine by the left and right pair of travel devices based on the amount of operation on the left and right pair of travel devices, determines the position of the outer shell of the work machine on the side that rotates toward the virtual wall when the work machine rotates based on the rotation direction, and controls the travel speed based on the virtual wall and the determined position of the outer shell of the work machine.

4. The system according to claim 2, wherein the processor, when the amount of operation for the left and right pair of traveling devices is different, identifies the position of the outer shell of the working machine on the side that rotates toward the virtual wall when the working machine turns, and controls the travel speed based on the virtual wall and the identified position of the outer shell of the working machine.

5. The system according to claim 1, wherein the processor determines the position of the pivot center of the work machine based on the travel speed of each of the left and right travel devices, determines the pivot angle until the outer shell of the work machine contacts the virtual wall when the work machine is pivoted by the left and right travel devices, based on the virtual wall, the position of the pivot center, and the position of the outer shell of the work machine, and controls the travel speed based on the pivot angle.

6. The system according to claim 1, wherein the processor controls the travel speed based on the length of an arc whose central angle is the angle from the point where it passes through one of the pair of left and right traveling devices until the outer shell of the work machine touches the virtual wall.

7. The system according to claim 6, wherein the processor controls the travel speed based on the length of the arc, which passes through one of the left and right travel devices, is centered on the pivot point of the work machine, and the central angle is the angle at which the outer shell of the work machine contacts the virtual wall.

8. The system according to claim 1, wherein the pair of left and right running gears are a pair of left and right tracks.

9. The system according to claim 1, wherein the work machine comprises a pair of left and right traveling devices, the processor determines a speed limit based on the angle at which the outer shell of the work machine contacts the virtual wall, receives an input variable for each of the left and right traveling devices, calculates a target speed for each of the left and right traveling devices based on the speed limit and the input variable, and controls the traveling speed such that the ratio of the command speed indicated by the input variable for the first traveling device of the left and right traveling devices to the target speed is equal to the ratio of the command speed indicated by the input variable for the second traveling device of the left and right traveling devices to the target speed.

10. A method for controlling a work machine having a traveling body equipped with a pair of left and right traveling devices, comprising the steps of: identifying a virtual wall which is a surface that prohibits the entry of the work machine; and, when the operation on the traveling body is a turning operation, controlling the travel speed of each of the left and right traveling devices such that the virtual wall and the outer shell of the work machine do not come into contact.

11. A program for causing a computer that controls a work machine having a traveling body equipped with a pair of left and right traveling devices to perform the steps of: identifying a virtual wall which is a surface that prohibits the work machine from entering; and, when the operation on the traveling body is a turning operation, controlling the travel speed of each of the left and right traveling devices so that the virtual wall and the outer shell of the work machine do not come into contact.

Images