A working machine, a method for controlling a working machine, and a system

Abstract

To properly determine whether an object exists around a work machine.SOLUTION: A work machine comprises a vehicle body, traveling wheels, a steering actuator, an articulate actuator, a steering angle sensor, an articulate angle sensor, an object sensor, and a controller. The vehicle body includes a rear frame and a front frame. The front frame is connected to the rear frame so as to be rotatable to the left and right. The steering actuator steers the traveling wheels to the left and right. The articulate actuator changes an articulate angle between the rear frame and the front frame. The object sensor detects an object around the work machine, and outputs a signal indicating the presence or absence of the object. The controller sets a detection range around the work machine. The controller sets the detection range according to the steering angle and the articulate angle.SELECTED DRAWING: Figure 9

Description

Technical Field

[0005]

[0001] The present invention relates to a working machine, a method for controlling a working machine, and a system.

Background Art

[0002] Conventionally, in a working machine, a technique for detecting a surrounding person or an obstacle by a sensor such as a radar has been used. For example, Patent Document 1 discloses a forklift equipped with an object detection system. The object detection system includes a radar device such as a millimeter-wave radar. The radar device transmits radio waves or ultrasonic waves and receives the radio waves or ultrasonic waves reflected by an object to detect the presence or absence of the object.

[0003] In the above object detection system, when all objects that have entered the measurable range of the radar device are detected and an alarm is output, the alarm will be frequently issued. Therefore, in the above object detection system, the controller sets a detection range around the forklift, and when an object is detected within the detection range, an alarm is issued. Also, the detection range is changed according to the vehicle speed and steering angle of the forklift.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The object detection system described above is said to be able to appropriately determine whether or not an object is present around a forklift by changing the detection range according to the vehicle speed and steering angle. However, in the case of work machines with a large degree of freedom in the posture of the vehicle body, such as a motor grader, simply applying the above technology is not sufficient. The objective of the present invention is to appropriately determine whether or not an object is present around a work machine. [Means for solving the problem]

[0006] A work machine according to a first aspect of the present invention comprises a vehicle body, running wheels, a steering actuator, an articulated actuator, a steering angle sensor, an articulated angle sensor, an object sensor, and a controller. The vehicle body includes a rear frame and a front frame. The front frame is connected to the rear frame so as to be rotatable left and right. The running wheels are supported by the vehicle body. The steering actuator steers the running wheels left and right. The articulated actuator changes the articulated angle between the rear frame and the front frame. The steering angle sensor detects the steering angle of the running wheels. The articulated angle sensor detects the articulated angle. The object sensor detects objects around the work machine and outputs a signal indicating the presence or absence of an object. The controller sets a detection range around the work machine. The controller determines the presence or absence of an object within the detection range based on the signal from the object sensor. The controller sets the detection range according to the steering angle and the articulated angle.

[0007] A method according to a second aspect of the present invention is a method for controlling a work machine. The work machine includes a rear frame, a body, running wheels, a steering actuator, and an articulated actuator. The body includes a rear frame and a front frame. The front frame is connected to the rear frame so as to be rotatable from side to side. The running wheels are supported by the body. The steering actuator steers the running wheels from side to side. The articulated actuator changes the articulation angle between the rear frame and the front frame. The method comprises detecting the steering angle, detecting the articulated angle, receiving a signal indicating the presence or absence of an object around the work machine, setting a detection range around the work machine according to the steering angle and the articulated angle, and determining the presence or absence of an object within the detection range based on a signal from an object sensor.

[0008] A third aspect of the present invention is a system for controlling a work machine. The work machine includes a rear frame, a body, wheels, a steering actuator, and an articulated actuator. The body includes a rear frame and a front frame. The front frame is connected to the rear frame so as to be rotatable left and right. The wheels are supported by the body. The steering actuator steers the wheels left and right. The articulated actuator changes the articulation angle between the rear frame and the front frame. The system comprises a steering angle sensor, an articulated angle sensor, an object sensor, and a controller. The steering angle sensor detects the steering angle of the wheels. The articulated angle sensor detects the articulation angle. The object sensor detects objects around the work machine and outputs a signal indicating the presence or absence of an object. The controller sets a detection range around the work machine. The controller determines the presence or absence of an object within the detection range based on the signal from the object sensor. The controller sets the detection range according to the steering angle and the articulated angle. [Effects of the Invention]

[0009] In this invention, the detection range for objects around the work machine is set according to the steering angle and the articulation angle. This makes it possible to appropriately determine whether or not an object is present around the work machine. [Brief explanation of the drawing]

[0010] [Figure 1] This is a perspective view of the work machine according to the embodiment. [Figure 2] This is a side view of the work machine. [Figure 3] This is a top view of the front of the work machine. [Figure 4] This is a front view of the front of the work machine. [Figure 5] This is a schematic diagram showing the configuration of the control system for a work machine. [Figure 6] This is a top view showing an example of the detection range. [Figure 7] This flowchart shows the process for setting the detection range. [Figure 8] This flowchart shows the process for setting the detection range. [Figure 9] This is a top view showing the detection range according to the processing of Change 1. [Figure 10] This is a top view showing the detection range according to the processing of Change 2. [Figure 11] This is a top view showing the detection range according to the processing of Change 3. [Figure 12] This is a top view showing the detection range according to the processing of Change 3. [Figure 13] This is a top view showing the detection range according to the processing of Change 4. [Figure 14] This is a top view showing the detection range according to the processing of Change 5. [Figure 15] This is a top view showing the detection range according to the processing of Change 5. [Figure 16] This is a top view showing the detection range according to the processing of change 6. [Figure 17] This is a top view showing the detection range according to the processing of Change 7. [Figure 18]It is a top view showing the detection range according to the process of Change 7. [Figure 19] It is a top view showing the detection range according to the process of Change 8. [Figure 20] It is a top view showing the detection range according to the process of Change 8. [Figure 21] It is a top view showing the detection range according to the process of Change 9. [Figure 22] It is a top view showing the detection range according to the process of Change 9. [Figure 23] It is a top view showing the detection range according to the process of Change 9. [Figure 24] It is a top view showing the detection range according to the process of Change 9. [Figure 25] It is a top view showing the detection range according to the modification.

Embodiments for Carrying Out the Invention

[0011] Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view of a working machine 1 according to an embodiment. FIG. 2 is a side view of the working machine 1. As shown in FIG. 1, the working machine 1 includes a vehicle body 2, traveling wheels 3A, 3B, 4A - 4D, and a working device 5. The vehicle body 2 includes a front frame 11, a rear frame 12, a cab 13, and a power chamber 14.

[0012] The rear frame 12 is connected to the front frame 11. The front frame 11 is connected to the rear frame 12 so as to be rotatable with respect to the rear frame 12. As will be described later, the front frame 11 is rotatable left and right with respect to the rear frame 12.

[0013] In the following description, the front, rear, left, and right directions are defined in a state where the articulation angle of the front frame 11 with respect to the rear frame 12 is zero, that is, in a state where the front frame 11 and the rear frame 12 are straight, for each of the front, rear, left, and right directions of the vehicle body 2.

[0014] The cab 13 and the power unit 14 are located on the rear frame 12. The cab 13 has a driver's seat (not shown). The power unit 14 is located behind the cab 13. The front frame 11 extends forward from the rear frame 12.

[0015] The running wheels 3A, 3B, and 4A-4D are rotatably supported on the vehicle body 2. The running wheels 3A, 3B, and 4A-4D include the front wheels 3A and 3B and the rear wheels 4A-4D. The front wheels 3A and 3B are positioned apart from each other in the left-right direction. The front wheels 3A and 3B are mounted on the front frame 11. The rear wheels 4A-4D are mounted on the rear frame 12.

[0016] The work implement 5 is movably connected to the vehicle body 2. The work implement 5 includes a support member 15 and a blade 16. The support member 15 is movably connected to the vehicle body 2. The support member 15 supports the blade 16. The support member 15 includes a drawbar 17 and a circle 18. The drawbar 17 is located below the front frame 11.

[0017] The drawbar 17 is connected to the front portion 19 of the front frame 11. The drawbar 17 extends rearward from the front portion 19 of the front frame 11. The drawbar 17 is supported relative to the front frame 11 so as to be able to swing at least vertically and horizontally in the vehicle body 2. For example, the front portion 19 includes a ball joint. The drawbar 17 is rotatably connected to the front frame 11 via the ball joint.

[0018] Circle 18 is connected to the rear of the drawbar 17. Circle 18 is rotatably supported relative to the drawbar 17. The blade 16 is connected to Circle 18. The blade 16 is supported by the drawbar 17 via Circle 18. As shown in Figure 2, the blade 16 is supported by Circle 18 so as to be rotatable around the tilt axis 21. The tilt axis 21 extends in the left-right direction.

[0019] Figure 3 is a top view of the front of the work machine 1. As shown in Figure 3, the work machine 1 is equipped with a first steering shaft 43A and a second steering shaft 43B. The first steering shaft 43A and the second steering shaft 43B are mounted on the front frame 11. The first steering shaft 43A and the second steering shaft 43B extend in the vertical direction. The front wheel 3A is supported so as to be rotatable around the first steering shaft 43A. The front wheel 3B is supported so as to be rotatable around the second steering shaft 43B. In other words, the front wheels 3A and 3B are steerable wheels.

[0020] The work machine 1 is equipped with multiple steering actuators 41A, 41B for steering the front wheels 3A, 3B. The multiple steering actuators 41A, 41B are used to steer the front wheels 3A, 3B. For example, the multiple steering actuators 41A, 41B are hydraulic cylinders. The multiple steering actuators 41A, 41B are connected to the front wheels 3A, 3B, respectively. The multiple steering actuators 41A, 41B extend and retract hydraulically. In the following description, the extension and retraction of the hydraulic cylinders including the multiple steering actuators 41A, 41B will be referred to as "stroke motion".

[0021] The multiple steering actuators 41A, 41B include a left steering cylinder 41A and a right steering cylinder 41B. The left steering cylinder 41A and the right steering cylinder 41B are positioned apart from each other in the left-right direction.

[0022] The left steering cylinder 41A is connected to the front frame 11 and the front wheel 3A. The right steering cylinder 41B is connected to the front frame 11 and the front wheel 3B. The stroke action of the left steering cylinder 41A and the right steering cylinder 41B steers the front wheels 3A and 3B.

[0023] The working machine 1 includes an articulated shaft 44. The articulated shaft 44 is provided on the front frame 11 and the rear frame 12. The articulated shaft 44 extends in the vertical direction. The front frame 11 and the rear frame 12 are connected to each other so as to be rotatable around the articulated shaft 44.

[0024] In the following explanation, the state in which the vehicle body 2 is bent due to the rotation of the front frame 11 and the rear frame 12 around the articulation axis 44 will be referred to as the "articulated state." The state in which the vehicle body 2 is not in the articulated state, that is, the state in which the front frame 11 and the rear frame 12 are aligned in a straight line, will be referred to as the "straight state."

[0025] The work machine 1 is equipped with a plurality of articulated actuators 27, 28. The plurality of articulated actuators 27, 28 are used to rotate the front frame 11 relative to the rear frame 12. For example, the plurality of articulated actuators 27, 28 are hydraulic cylinders. The plurality of articulated actuators 27, 28 are connected to the front frame 11 and the rear frame 12. The plurality of articulated actuators 27, 28 extend and retract hydraulically.

[0026] The multiple articulated actuators 27, 28 include a left articulated cylinder 27 and a right articulated cylinder 28. The left articulated cylinder 27 and the right articulated cylinder 28 are positioned apart from each other in the left-right direction.

[0027] The left articulated cylinder 27 is connected to the front frame 11 and the rear frame 12 on the left side of the vehicle body 2. The right articulated cylinder 28 is connected to the front frame 11 and the rear frame 12 on the right side of the vehicle body 2. The stroke action of the left articulated cylinder 27 and the right articulated cylinder 28 causes the front frame 11 to rotate left and right relative to the rear frame 12.

[0028] Figure 4 is a front view of the front of the work machine 1. As shown in Figure 4, the work machine 1 is equipped with a lean mechanism 6. The lean mechanism 6 tilts the front wheels 3A and 3B to the left and right. The lean mechanism 6 includes an axle beam 56, a leaning rod 57, and a leaning actuator 60. The axle beam 56 extends from the front frame 11 to the left and right. The axle beam 56 is supported on the front frame 11 so as to be rotatable around a pivot axis 58.

[0029] The axle beam 56 is connected to the front wheel 3A via the wheel bracket 59A. The axle beam 56 rotatably supports the front wheel 3A around the leaning axis 54A. The axle beam 56 is connected to the front wheel 3B via the wheel bracket 59B. The axle beam 56 rotatably supports the front wheel 3B around the leaning axis 54B. The leaning axes 54A and 54B extend in the longitudinal direction.

[0030] The leaning rod 57 extends from left to right through the front frame 11. The leaning rod 57 connects the front wheels 3A and 3B to each other. The leaning rod 57 is connected to the front wheel 3A via the wheel bracket 59A. The leaning rod 57 is connected to the front wheel 3B via the wheel bracket 59B.

[0031] The leaning actuator 60 is used to tilt (lean) the front wheels 3A and 3B. For example, the leaning actuator 60 is a hydraulic cylinder. The leaning actuator 60 is connected to the front frame 11 and the front wheels 3A and 3B. The leaning actuator 60 extends and retracts by hydraulic pressure. That is, by extending and retracting the leaning actuator 60, the front wheels 3A and 3B rotate around the leaning axes 54A and 54B. As a result, the front wheels 3A and 3B tilt to the left and right.

[0032] As shown in Figure 2, the work machine 1 is equipped with a plurality of actuators 22-26 for changing the posture of the work machine 5. For example, the plurality of actuators 22-25 are hydraulic cylinders. Actuators 26 are rotary actuators. In this embodiment, actuator 26 is a hydraulic motor. Actuator 26 may also be an electric motor.

[0033] Multiple actuators 22-25 are connected to the work implement 5. The multiple actuators 22-25 extend and retract hydraulically. By extending and retracting, the multiple actuators 22-25 change the posture of the work implement 5 relative to the vehicle body 2.

[0034] In detail, the multiple actuators 22-25 include a left lift cylinder 22, a right lift cylinder 23, a drawbar shift cylinder 24, and a blade tilt cylinder 25.

[0035] The left lift cylinder 22 and the right lift cylinder 23 are positioned apart from each other in the left-right direction. The left lift cylinder 22 and the right lift cylinder 23 are connected to the drawbar 17. The left lift cylinder 22 and the right lift cylinder 23 are connected to the front frame 11 via the lifter bracket 29. The stroke motion of the left lift cylinder 22 and the right lift cylinder 23 causes the drawbar 17 to swing up and down. As a result, the blade 16 moves up and down.

[0036] The drawbar shift cylinder 24 is connected to the drawbar 17 and the front frame 11. The drawbar shift cylinder 24 is connected to the front frame 11 via a lifter bracket 29. The drawbar shift cylinder 24 extends diagonally downward from the front frame 11 toward the drawbar 17. The stroke motion of the drawbar shift cylinder 24 causes the drawbar 17 to swing from side to side.

[0037] The blade tilt cylinder 25 is connected to the circle 18 and the blade 16. The stroke motion of the blade tilt cylinder 25 causes the blade 16 to rotate around the tilt axis 21.

[0038] The actuator 26 is connected to the drawbar 17 and the circle 18. The actuator 26 rotates the circle 18 relative to the drawbar 17. As a result, the blade 16 rotates around a rotation axis that extends in the vertical direction.

[0039] Figure 5 is a schematic diagram showing the configuration of the control system of the work machine 1. As shown in Figure 5, the work machine 1 includes a drive source 31, a hydraulic pump 32, and a power transmission device 33. The work machine 1 also includes a steering valve 42A, an articulating valve 42B, a leaning valve 42C, and a work machine valve 34. The drive source 31 is, for example, an internal combustion engine. Alternatively, the drive source 31 may be an electric motor, or a hybrid of an internal combustion engine and an electric motor.

[0040] The hydraulic pump 32 is driven by the drive source 31 and discharges hydraulic fluid. The hydraulic pump 32 supplies hydraulic fluid to the steering valve 42A, the articulate valve 42B, the leaning valve 42C, and the work machine valve 34. This operates multiple steering actuators 41A, 41B, multiple articulate actuators 27, 28, the leaning actuator 60, and multiple actuators 22-26. Although only one hydraulic pump 32 is shown in Figure 5, multiple hydraulic pumps may be provided.

[0041] The steering valve 42A is connected to the hydraulic pump 32 and a plurality of steering actuators 41A, 41B via a hydraulic circuit. The steering valve 42A controls the flow rate of hydraulic fluid supplied from the hydraulic pump 32 to the plurality of steering actuators 41A, 41B. The hydraulic fluid from the hydraulic pump 32 is supplied to the steering valve 42A, causing the plurality of steering actuators 41A, 41B to perform a stroke operation.

[0042] The articulated valve 42B is connected to the hydraulic pump 32 and the multiple articulated actuators 27 and 28 via a hydraulic circuit. The articulated valve 42B controls the flow rate of hydraulic fluid supplied from the hydraulic pump 32 to the multiple articulated actuators 27 and 28. The supply of hydraulic fluid from the hydraulic pump 32 to the articulated valve 42B causes the multiple articulated actuators 27 and 28 to perform a stroking motion.

[0043] The leaning valve 42C is connected to the hydraulic pump 32 and the leaning actuator 60 via a hydraulic circuit. The leaning valve 42C controls the flow rate of hydraulic fluid supplied from the hydraulic pump 32 to the leaning actuator 60. The supply of hydraulic fluid from the hydraulic pump 32 to the leaning valve 42C causes the leaning actuator 60 to perform a stroke motion.

[0044] The work equipment valve 34 is connected to the hydraulic pump 32 and a plurality of actuators 22-26 via a hydraulic circuit. The work equipment valve 34 includes a plurality of valves connected to each of the actuators 22-26. The work equipment valve 34 controls the flow rate of hydraulic fluid supplied from the hydraulic pump 32 to the plurality of actuators 22-26.

[0045] The power transmission device 33 transmits the driving force from the drive source 31 to the rear wheels 4A-4D. The power transmission device 33 may include a torque converter and / or multiple transmission gears. Alternatively, the power transmission device 33 may be a transmission such as an HST (Hydraulic Static Transmission) or an HMT (Hydraulic Mechanical Transmission).

[0046] The work machine 1 includes a steering operating member 45, an articulating operating member 46, a leaning operating member 47, a work machine operating member 48, a shift operating member 49, and an accelerator operating member 50.

[0047] The steering control member 45 is operable by the operator to steer the front wheels 3A and 3B. The steering control member 45 is a lever such as a joystick. Alternatively, the steering control member 45 may be a member other than a lever. For example, the steering control member 45 may be a steering wheel. The steering control member 45 outputs a steering operation signal indicating the operator's operation of the steering control member 45.

[0048] The articulated operating member 46 is operable by an operator to rotate the front frame 11 relative to the rear frame 12. The articulated operating member 46 is a lever such as a joystick. Alternatively, the articulated operating member 46 may be a member other than a lever. The articulated operating member 46 outputs an articulated operation signal indicating operation by the operator on the articulated operating member 46.

[0049] The leaning control member 47 is operable by the operator to tilt the front wheels 3A and 3B. The leaning control member 47 is a lever such as a joystick. Alternatively, the leaning control member 47 may be another component such as a switch or a touch panel. The leaning control member 47 outputs a leaning operation signal indicating the operator's operation of the leaning control member 47.

[0050] The work implement operating member 48 is operable by the operator to change the posture of the work implement 5. The work implement operating member 48 includes, for example, a plurality of work implement levers. Alternatively, the work implement operating member 48 may be a switch or other component such as a touch panel. The work implement operating member 48 outputs a signal indicating operation by the operator to the work implement operating member 48.

[0051] The shift operating member 49 is operable by an operator to switch between forward and reverse movement of the work machine 1. The shift operating member 49 includes, for example, a shift lever. Alternatively, the shift operating member 49 may be other components such as a switch or a touch panel. The shift operating member 49 outputs a signal indicating operation by the operator to the shift operating member 49.

[0052] The accelerator operating member 50 is operable by an operator to move the work machine 1. The accelerator operating member 50 includes, for example, an accelerator pedal. Alternatively, the accelerator operating member 50 may be other components such as a switch or a touch panel. The accelerator operating member 50 outputs a signal indicating operation by the operator to the accelerator operating member 50.

[0053] As shown in Figure 5, the work machine 1 includes a controller 37. The controller 37 includes a storage device 38 and a processor 39. The processor 39 is, for example, a CPU, which executes a program for controlling the work machine 1. The storage device 38 includes memory such as RAM and ROM, and auxiliary storage such as an SSD or HDD. The storage device 38 stores the program and data for controlling the work machine 1.

[0054] The controller 37 controls the power transmission device 33 in response to the operation of the shift operating member 49. This switches the direction of travel of the work machine 1 between forward and reverse. It also switches the speed gear of the power transmission device 33. Alternatively, the shift operating member 49 may be mechanically connected to the power transmission device 33. By mechanically transmitting the operation of the shift operating member 49 to the power transmission device 33, the forward and reverse gears, or the variable gear, of the power transmission device 33 may be switched.

[0055] The controller 37 controls the drive source 31 and the power transmission device 33 in response to the operation of the accelerator operating member 50. This causes the work machine 1 to move. The controller 37 also controls the hydraulic pump 32 and the work machine valve 34 in response to the operation of the work machine operating member 48. This causes the work machine 5 to operate.

[0056] The controller 37 acquires the amount of movement of the steering control member 45 based on the steering control signal from the steering control member 45. The controller 37 extends and retracts multiple steering actuators 41A and 41B by controlling the steering valve 42A in response to the steering control signal. As a result, the controller 37 changes the steering angle θs of the front wheels 3A and 3B.

[0057] As shown in Figure 3, the steering angle θs is the angle at which the front wheels 3A and 3B rotate relative to the front frame 11 around the first steering axis 43A and the second steering axis 43B. More specifically, the steering angle θs is the rotation angle of the front wheels 3A and 3B with respect to the first centerline L1 of the front frame 11. The first centerline L1 extends in the longitudinal direction of the front frame 11.

[0058] The steering angle θs changes from the neutral position to the left or right due to the stroke movement of multiple steering actuators 41A and 41B. The steering angle θs at the neutral position is zero degrees. The front wheels 3A and 3B are positioned parallel to the first centerline L1 of the front frame 11 at the neutral position. In Figure 3, 3A' and 3B' show the front wheels when they are steered to the right by a steering angle θs from the neutral position.

[0059] The controller 37 obtains the amount of movement of the articulated operating member 46 based on the articulated operating signal from the articulated operating member 46. The controller 37 controls the articulated valve 42B. For example, the controller 37 extends and retracts the left articulated cylinder 27 and the right articulated cylinder 28 by controlling the articulated valve 42B in response to the articulated operating signal. In this way, the controller 37 changes the articulation angle θa.

[0060] As shown in Figure 3, the articulation angle θa is the angle at which the front frame 11 rotates relative to the rear frame 12 around the articulation axis 44. More specifically, the articulation angle θa is the angle formed by the first centerline L1 of the front frame 11 and the second centerline L2 of the rear frame 12.

[0061] The second centerline L2 extends in the front-rear direction of the rear frame 12. The second centerline L2 passes through the articulation axis 44 in a top view of the work machine 1. The articulation angle θa changes from the neutral position to the left and right. The articulation angle θa at the neutral position is zero. The articulation angle θa to the left is a positive value, and the articulation angle θa to the right is a negative value.

[0062] When the articulation angle θa is zero, the direction of the second centerline L2 coincides with the direction of the first centerline L1. That is, when the articulation angle θa is zero, the vehicle body 2 is in a straight line. Note that Figure 3 shows the front frame 11 rotated by an articulation angle θa around the articulation axis 44.

[0063] The controller 37 obtains the amount of operation of the leaning operating member 47 based on the leaning operation signal from the leaning operating member 47. The controller 37 controls the leaning valve 42C. For example, the controller 37 extends or retracts the leaning actuator 60 by controlling the leaning valve 42C in response to the leaning operation signal. In this way, the controller 37 changes the leaning angle θl in response to the operator's operation of the leaning operating member 47.

[0064] As shown in Figure 4, the leaning angle θl is the angle at which the front wheels 3A and 3B tilt in the left-right direction when viewed from the front of the vehicle body 2. For example, the leaning angle θl is the angle at which the front wheels 3A and 3B tilt around the leaning axes 54A and 54B when viewed from the front of the vehicle body 2.

[0065] In the following explanation, the state in which the front wheels 3A and 3B are upright relative to the horizontal plane (shown by solid lines 3A and 3B) will be referred to as the neutral position of the front wheels 3A and 3B. When the front wheels 3A and 3B are in the neutral position, the leaning angle θl is zero degrees. In Figure 4, 3A' and 3B' represent the front wheels tilted to the left from the neutral position by a leaning angle θl.

[0066] The work machine 1 is equipped with a steering angle sensor 51, an articulate angle sensor 52, and a leaning angle sensor 53. The steering angle sensor 51 is used to detect the steering angle θs of the front wheels 3A and 3B. The steering angle sensor 51 outputs a signal indicating the steering angle θs.

[0067] The articulated angle sensor 52 is used to detect the articulated angle of the front frame 11 relative to the rear frame 12. The articulated angle sensor 52 outputs a signal indicating the articulated angle θa. The leaning angle sensor 53 is used to detect the leaning angle θl of the front wheels 3A and 3B. The leaning angle sensor 53 outputs a signal indicating the leaning angle θl.

[0068] The steering angle sensor 51, articulate angle sensor 52, and leaning angle sensor 53 may each be an IMU (Inertial Measurement Unit). Alternatively, the steering angle sensor 51, articulate angle sensor 52, and leaning angle sensor 53 may each be a camera. In that case, the controller 37 may calculate the steering angle θs, articulate angle θa, and leaning angle θl by analyzing the images acquired by each of the sensors 51-53.

[0069] Alternatively, the steering angle sensor 51, articulate angle sensor 52, and leaning angle sensor 53 may be sensors that detect the stroke amount of the steering actuators 41A and 41B, the stroke amount of the articulate cylinders 27 and 28, and the stroke amount of the leaning actuator 60, respectively. In that case, the controller 37 may calculate the steering angle θs, articulate angle θa, and leaning angle θl from the stroke amounts of the steering actuators 41A and 41B, the stroke amounts of the articulate cylinders 27 and 28, and the stroke amount of the leaning actuator 60, respectively.

[0070] Alternatively, the steering angle sensor 51 may directly detect the steering angle θs. The articulate angle sensor 52 may directly detect the articulate angle θa. The leaning angle sensor 53 may directly detect the leaning angle θl.

[0071] As shown in Figure 5, the work machine 1 is equipped with object sensors 61 and 62 and an output device 63. The object sensors 61 and 62 detect objects in the vicinity of the work machine 1. The object sensors 61 and 62 are, for example, radar devices such as millimeter-wave radar. Alternatively, the object sensors 61 and 62 may be other types of sensors such as ultrasonic sensors, cameras, or LIDAR (Light Detection and Ranging) devices. The object sensors output signals indicating the presence or absence of objects in the vicinity of the work machine 1.

[0072] The object sensors 61 and 62 include a first object sensor 61 and a second object sensor 62. The first object sensor 61 detects objects in front of the vehicle body 2. The first object sensor 61 is mounted, for example, on the front frame 11. Alternatively, the first object sensor 61 may be mounted in another location, such as the cab 13. The second object sensor 62 detects objects behind the vehicle body 2. The second object sensor 62 is mounted, for example, on the rear frame 12, or it may be mounted in another location, such as the cab 13 or the power compartment 14.

[0073] The output device 63 is, for example, a display. The output device 63 displays an image in response to a command signal from the controller 37. Alternatively, the output device 63 may be a speaker. The output device 63 may output sound in response to a command signal from the controller 37.

[0074] The controller 37 sets detection ranges 71 and 72 around the work machine 1 and determines the presence or absence of an object within the detection ranges 71 and 72 based on signals from object sensors 61 and 62. For example, as shown in Figure 6, the controller 37 sets a first detection range 71 in front of the vehicle body 2. The controller 37 sets a second detection range 72 behind the vehicle body 2. If the controller 37 detects an object 100 within the detection ranges 71 and 72, it causes the output device 63 to output an alarm.

[0075] The controller 37 stores the first reference range 73 of the first detection range 71 and the second reference range 74 of the second detection range 72. The first reference range 73 and the second reference range 74 are set based on the width L0 of the vehicle body 2 (hereinafter referred to as "vehicle width"). The width of the first reference range 73 and the width of the second reference range 74 are the same as the maximum vehicle width L0 of the work machine 1 excluding the work implement 5.

[0076] The controller 37 sets the detection ranges 71 and 72 according to the steering angle θs, the articulation angle θa, and the leaning angle θl. The controller 37 changes the detection ranges 71 and 72 from the reference ranges 73 and 74 according to the steering angle θs, the articulation angle θa, and the leaning angle θl. The method of setting the detection ranges 71 and 72 by the controller 37 will be described below. Figures 7 and 8 are flowcharts showing the process for setting the detection ranges 71 and 72 performed by the controller 37.

[0077] As shown in Figure 7, in step S1, the controller 37 acquires the steering angle θs. The controller 37 acquires the steering angle θs based on the signal from the steering angle sensor 51. In step S2, the controller 37 acquires the articulate angle θa. The controller 37 acquires the articulate angle θa based on the signal from the articulate angle sensor 52. In step S3, the controller 37 acquires the leaning angle θl. The controller 37 acquires the leaning angle θl based on the signal from the leaning angle sensor 53.

[0078] In step S4, the controller 37 determines whether the steering angle θs is 0 degrees. In step S5, the controller 37 determines whether the articulate angle θa is 0 degrees. In step S6, the controller 37 determines whether the leaning angle θl is 0 degrees.

[0079] When the steering angle θs, articulate angle θa, and leaning angle θl are all 0 degrees, in step S7, the controller 37 sets the reference ranges 73 and 74 as the detection ranges 71 and 72. That is, when the work machine 1 is not steered, is not leaning, and is moving in a straight line, the controller 37 sets the reference ranges 73 and 74 as the detection ranges 71 and 72. In detail, as shown in Figure 6, the controller 37 sets the first reference range 73 as the first detection range 71. The controller 37 also sets the second reference range 74 as the second detection range 72.

[0080] In step S6, if the leaning angle θl is not 0 degrees, the process proceeds to step S8. In step S8, the controller 37 sets the detection ranges 71 and 72 by changing the reference ranges 73 and 74 according to the process of change 1. Figure 9 is a top view showing the detection ranges 71 and 72 according to the process of change 1.

[0081] As shown in Figure 9, in the process of modification 1, the controller 37 expands the detection ranges 71 and 72 on the same side as the direction in which the front wheels 3A and 3B are leaning (hereinafter referred to as the "leaning direction"). In other words, when the work machine 1 is not steered and is moving straight while leaning, the controller 37 expands the detection ranges 71 and 72 on the same side as the leaning direction.

[0082] For example, if the front wheels 3A and 3B are leaning to the left, the controller 37 expands the first detection range 71 to the left from the first reference range 73. The controller 37 also expands the second detection range 72 to the left from the second reference range 74. The controller 37 does not expand the detection ranges 71 and 72 to the right. In this case, the width Lall of the detection ranges 71 and 72 is expressed by the following equation (1). Lall = L0 + Ll (1) Ll is the increment in the detection range during leaning. The increment Ll during leaning indicates the amount of lateral outward displacement of the front wheels 3A and 3B due to leaning. The increment Ll during leaning is expressed by the following equation (2). Ll = D × cosθl (2) As shown in Figure 4, D is the outer diameter of the front wheels 3A and 3B. Although not shown in the illustration, in the process of modification 1, if the front wheels 3A and 3B are leaning to the right, the controller 37 expands the first detection range 71 to the right from the first reference range 73, and expands the second detection range 72 to the right from the second reference range 74.

[0083] In step S5, if the articulation angle θa is not 0 degrees, the process proceeds to step S9. In step S9, the controller 37 determines whether the leaning angle θl is 0 degrees. In step S9, if the leaning angle θl is 0 degrees, the process proceeds to step S10.

[0084] In step S10, the controller 37 sets the detection ranges 71 and 72 by changing the reference ranges 73 and 74 according to the process of modification 2. Figure 10 is a top view showing the detection ranges 71 and 72 according to the process of modification 2. As shown in Figure 10, in the process of modification 2, the controller 37 curves the detection ranges 71 and 72 according to the turning radius of the work machine 1 corresponding to the articulation angle θa. That is, when the work machine 1 is not steered, is not leaning, and is turning in an articulated state, the detection ranges 71 and 72 are curved to match the turning trajectory A1 and A2 of the work machine 1.

[0085] For example, when the work machine 1 rotates to the left in an articulated state, the controller 37 curves the detection range 71,72 to the left. The controller 37 stores data showing the relationship between the articulation angle θa and the rotation radius of the work machine 1, and may calculate the rotation radius from the articulation angle θa by referring to this data. The width Lall of the detection range 71,72 is the same as the width of the reference range 73,74, and is expressed by the following equation (3). Lall = L0 (3) Although not shown in the diagram, in the process of modification 2, if the work machine 1 rotates to the right while in an articulated state, the controller 37 curves the detection ranges 71 and 72 to the right.

[0086] If the leaning angle θl is not 0 degrees in step S9, the process proceeds to step S11. In step S11, the controller 37 sets the detection ranges 71 and 72 by changing the reference ranges 73 and 74 according to the process of modification 3. Figures 11 and 12 are top views showing the detection ranges 71 and 72 according to the process of modification 3.

[0087] As shown in Figures 11 and 12, in the process of modification 3, the controller 37 curves the detection ranges 71 and 72 according to the turning radius of the work machine 1 corresponding to the articulation angle θa and leaning angle θl, and expands the detection ranges 71 and 72 on the same side as the leaning direction. That is, if the work machine 1 is not being steered and is turning in an articulated state while leaning, the controller 37 curves the detection ranges 71 and 72 in accordance with the turning trajectory of the work machine 1, and expands the detection ranges 71 and 72 on the same side as the leaning direction, similar to the process of modification 2. For example, the controller 37 may store data showing the relationship between the articulation angle θa, the leaning angle θl, and the turning radius of the work machine 1, and calculate the turning radius of the work machine 1 from the articulation angle θa and the leaning angle θl by referring to this data.

[0088] For example, as shown in Figure 11, when the work machine 1 is leaning to the left and rotating to the left in an articulated state, the controller 37 curves the detection ranges 71 and 72 to the left and expands the detection ranges 71 and 72 to the left by an increment of Ll. As shown in Figure 12, when the work machine 1 is leaning to the right and rotating to the left in an articulated state, the controller 37 curves the detection ranges 71 and 72 to the left and expands the detection ranges 71 and 72 to the right by an increment of Ll. The width Lall of the detection ranges 71 and 72 is expressed by equation (1) above.

[0089] Although not shown in the diagram, in the process of modification 3, if the work machine 1 rotates to the right due to the articulated state, the controller 37 curves the detection ranges 71 and 72 to the right and expands the detection ranges 71 and 72 to the same side as the leaning direction.

[0090] If the steering angle θs is not 0 degrees in step S4, the process proceeds to step S12 shown in Figure 8. In step S12, the controller 37 determines whether the articulate angle θa is 0 degrees. In step S13, the controller 37 determines whether the leaning angle θl is 0 degrees. If both the articulate angle θa and the leaning angle θl are 0 degrees, the process proceeds to step S14.

[0091] In step S14, the controller 37 sets the detection ranges 71 and 72 by changing the reference ranges 73 and 74 according to the process of modification 4. Figure 13 is a top view showing the detection ranges 71 and 72 according to the process of modification 4. As shown in Figure 13, in the process of modification 4, the controller 37 curves the detection ranges 71 and 72 according to the turning radius of the work machine 1 corresponding to the steering angle θs. That is, when the work machine 1 is not leaning and is in a straight line, and is turning by steering, the detection ranges 71 and 72 are curved to match the turning trajectory of the work machine 1.

[0092] For example, as shown in Figure 13, when the work machine 1 turns to the left due to steering, the controller 37 curves the detection ranges 71 and 72 to the left. For example, the controller 37 may store data showing the relationship between the steering angle θs and the turning radius of the work machine 1, and calculate the turning radius from the steering angle θs by referring to this data. The width Lall of the detection ranges 71 and 72 is the same as the width of the reference ranges 73 and 74, and is expressed by the above-mentioned equation (3). Although not shown in the figure, in the process of modification 4, when the work machine 1 turns to the right due to steering, the controller 37 curves the detection ranges 71 and 72 to the right.

[0093] If the leaning angle θl is not 0 degrees in step S13, the process proceeds to step S15. In step S15, the controller 37 sets the detection ranges 71 and 72 by changing the reference ranges 73 and 74 according to the process of change 5. Figures 14 and 15 are top views showing the detection ranges 71 and 72 according to the process of change 5.

[0094] As shown in Figures 14 and 15, in the process of modification 5, the controller 37 curves the detection ranges 71 and 72 according to the turning radius of the work machine 1 corresponding to the steering angle θs and leaning angle θl, and expands the detection ranges 71 and 72 on the same side as the leaning direction. That is, when the work machine 1 is in a straight line and turns by steering while leaning, the controller 37 curves the detection ranges 71 and 72 in accordance with the turning trajectory of the work machine 1, and expands the detection ranges 71 and 72 on the same side as the leaning direction. The controller 37 may store data showing the relationship between the steering angle θs, the leaning angle θl, and the turning radius of the work machine 1, and may calculate the turning radius of the work machine 1 from the steering angle θs and the leaning angle θl by referring to this data.

[0095] For example, as shown in Figure 14, when the work machine 1 leans to the left and turns to the left due to steering, the controller 37 curves the detection range 71,72 to the left and expands the detection range 71,72 to the left by an increment of Ll. As shown in Figure 15, when the work machine 1 leans to the right and turns to the left due to steering, the controller 37 curves the detection range 71,72 to the left and expands the detection range 71,72 to the right by an increment of Ll. The width Lall of the detection range 71,72 is expressed by the above-mentioned equation (1).

[0096] Although not shown in the diagram, in the process of modification 5, when the work machine 1 turns to the right due to steering, the controller 37 curves the detection ranges 71 and 72 to the right and expands the detection ranges 71 and 72 to the same side as the leaning direction.

[0097] In step S12, if the articulation angle θa is not 0 degrees, the process proceeds to step S16. In step S16, the controller 37 determines whether the steering angle θs and the articulation angle θa with the sign reversed are the same (i.e., θs = -θa). If the steering angle θs and the articulation angle θa with the sign reversed are the same, the process proceeds to step S17. In step S17, the controller 37 determines whether the leaning angle θl is 0 degrees. If the leaning angle θl is 0 degrees, the process proceeds to step S18.

[0098] In step S18, the controller 37 sets the detection ranges 71 and 72 by changing the reference ranges 73 and 74 according to the process of change 6. Figure 16 is a top view showing the detection ranges 71 and 72 according to the process of change 6.

[0099] As shown in Figure 16, when the steering angle θs and the articulate angle θa with the sign reversed are the same, the work machine 1 moves in a straight line in the articulated state. In the process of change 6, the controller 37 expands the reference ranges 73 and 74 in the left and right directions according to the articulate angle θa. The controller 37 expands the first detection range 71 from the first reference range 73 in the left and right direction opposite to the bending direction of the front frame 11 relative to the rear frame 12 (hereinafter referred to as the "articulate direction"). The controller 37 also expands the second detection range 72 from the second reference range 74 on the same side as the articulate direction.

[0100] For example, as shown in Figure 16, when the work machine 1 is moving straight with the front frame 11 bent to the left relative to the rear frame 12, the controller 37 expands the first detection range 71 to the right from the first reference range 73, and expands the second detection range 72 to the left from the second reference range 74. In this case, the width Lall of the detection ranges 71 and 72 is expressed by the following equation (4). Lall = L0 + La (4) La is the increment of the detection range in the articulated state. As shown in Figure 4, the increment La in the articulated state represents the amount of lateral outward displacement of the front wheels 3A and 3B in the articulated state. The increment La in the articulated state is expressed by the following equation (5). La = Lf × sinθa (5) As shown in Figure 3, Lf is the distance between the articulated axis 44 and the center P1 of the axle beam 56. Although not shown in the illustration, in the process of modification 6, if the front frame 11 is bent to the right relative to the rear frame 12 and the vehicle is moving straight, the controller 37 expands the first detection range 71 to the left from the first reference range 73 and expands the second detection range 72 to the right from the second reference range 74.

[0101] If the leaning angle θl is not 0 degrees in step S17, the process proceeds to step S19. In step S19, the controller 37 sets the detection ranges 71 and 72 by changing the reference ranges 73 and 74 according to the process of change 7. Figures 17 and 18 are top views showing the detection ranges 71 and 72 according to the process of change 7.

[0102] As shown in Figure 17, in the process of modification 7, the controller 37 expands the reference ranges 73 and 74 in the left-right direction according to the articulation angle θa, and also expands the detection ranges 71 and 72 on the same side as the leaning direction. That is, when the work machine 1 moves in a straight line in an articulated state while leaning, the controller 37 expands the detection ranges 71 and 72 from the reference ranges 73 and 74 in the left-right direction according to the articulation angle θa, and also expands the detection ranges 71 and 72 from the reference ranges 73 and 74 on the same side as the leaning direction.

[0103] For example, as shown in Figure 17, when the work machine 1 moves straight ahead in an articulated state to the left while leaning to the left, the controller 37 expands the first detection range 71 to the right by an increment La and expands the first detection range 71 to the left by an increment Ll. The controller 37 also expands the second detection range 72 to the left by an increment La and expands the second detection range 72 to the left by an increment Ll. In this case, the width Lall of the detection ranges 71 and 72 is expressed by the following equation (6). Lall = L0 + La + Ll (6) However, as shown in Figure 18, if the leaning direction is opposite to the articulating direction, the controller 37 does not expand the detection range 71,72 by the increment Ll during leaning. In other words, the controller 37 performs the modification 7 described above only when the leaning direction is the same as the articulating direction.

[0104] Although not shown in the diagram, in the process of modification 7, if the front frame 11 is leaning to the right and moving straight ahead in an articulated state to the right, the controller 37 expands the first detection range 71 to the left by an increment La and expands the first detection range 71 to the right by an increment Ll. In addition, the controller 37 expands the second detection range 72 to the right by an increment La and expands the second detection range 72 to the right by an increment Ll.

[0105] In step S16, if the steering angle θs and the articulate angle θa with the sign reversed are different (i.e., θs ≠ θa), the process proceeds to step 20.

[0106] In step S20, the controller 37 determines whether the leaning angle θl is 0 degrees. If the leaning angle θl is 0 degrees, the process proceeds to step S21. In step S21, the detection ranges 71 and 72 are set by changing the reference ranges 73 and 74 according to the process of change 8. Figures 19 and 20 are top views showing the detection ranges 71 and 72 according to the process of change 8.

[0107] As shown in Figure 19, in the modification 8 process, if the turning direction and articulation direction of the work machine 1 are the same, the controller 37 curves the detection ranges 71 and 72 according to the turning radius of the work machine 1 corresponding to the articulation angle θa and steering angle θs. That is, when the work machine 1 turns according to the articulation angle θa and steering angle θs while not leaning, the detection ranges 71 and 72 are curved to match the turning trajectory of the work machine 1.

[0108] For example, when the work machine 1 turns to the left due to the articulation angle θa and steering angle θs (θs > -θa), the controller 37 curves the detection range 71, 72 to the left. The controller 37 stores data showing the relationship between the articulation angle θa, the steering angle θs, and the turning radius of the work machine 1, and may calculate the turning radius from the articulation angle θa and the steering angle θs by referring to this data. The width Lall of the detection range 71, 72 is the same as the width of the reference range 73, 74, and is expressed by the above-mentioned equation (3).

[0109] Although not shown in the diagram, in the process of modification 8, when the rotation direction and articulation direction of the work machine 1 are the same, and the work machine 1 rotates to the right due to the articulation angle θa and steering angle θs (θs < -θa), the controller 37 curves the detection ranges 71 and 72 to the right.

[0110] As shown in Figure 20, in the process of modification 8, if the steering angle θs and the articulate angle θa have different signs, and the turning direction and articulate direction of the work machine 1 are opposite, the controller 37 curves the detection ranges 71 and 72 according to the turning radius of the work machine 1 corresponding to the articulate angle θa and steering angle θs, and expands the reference ranges 73 and 74 in the left and right directions according to the articulate angle θa.

[0111] For example, as shown in Figure 20, when the articulation direction is to the left and the rotation direction of the work machine 1 is to the right, the controller 37 expands the first detection range 71 to the right from the first reference range 73 and also curves the first detection range 71 to the right. In addition, the controller 37 expands the second detection range 72 to the left from the second reference range 74 and also curves the second detection range 72 to the right. In this case, the width Lall of the detection ranges 71 and 72 is expressed by the above-mentioned equation (4).

[0112] Although not shown in the diagram, in the process of modification 8, if the steering angle θs and the articulate angle θa (with the sign reversed) are different, and the articulate direction is to the right while the turning direction of the work machine 1 is to the left, the controller 37 expands the first detection range 71 to the left from the first reference range 73 and also curves the first detection range 71 to the left. In addition, the controller 37 expands the second detection range 72 to the right from the second reference range 74 and also curves the second detection range 72 to the left.

[0113] If the leaning angle θl is not 0 degrees in step S20, the process proceeds to step S22. In step S22, the controller 37 sets the detection ranges 71 and 72 by changing the reference ranges 73 and 74 according to the process of change 9. Figures 21 to 24 are top views showing the detection ranges 71 and 72 according to the process of change 9.

[0114] As shown in Figures 21 and 22, in the process of modification 9, if the articulation direction and the turning direction of the work machine 1 are the same, the controller 37 curves the detection ranges 71 and 72 according to the turning radius of the work machine 1 corresponding to the articulation angle θa, steering angle θs, and leaning angle θl, and expands the detection ranges 71 and 72 on the same side as the leaning direction. That is, when the work machine 1 turns while leaning according to the articulation angle θa and steering angle θs, the controller 37 curves the detection ranges 71 and 72 in accordance with the turning trajectory of the work machine 1, and expands the detection ranges 71 and 72 on the same side as the leaning direction. The controller 37 may store data showing the relationship between the articulation angle θa, steering angle θs, leaning angle θl, and the turning radius of the work machine 1, and calculate the turning radius of the work machine 1 from the articulation angle θa, steering angle θs, and leaning angle θl by referring to this data.

[0115] For example, as shown in Figure 21, when the work machine 1 leans to the left and turns to the left due to the articulation angle θa and steering angle θs, the controller 37 curves the detection range 71,72 to the left and expands the detection range 71,72 to the left by an increment Ll. As shown in Figure 22, when the work machine 1 leans to the right and turns to the left due to the articulation angle θa and steering angle θs, the controller 37 curves the detection range 71,72 to the left and expands the detection range 71,72 to the right by an increment Ll. The width Lall of the detection range 71,72 is expressed by equation (1) above.

[0116] Although not shown in the diagram, in the process of modification 9, if the articulation direction and the rotation direction of the work machine 1 are the same and the work machine 1 rotates to the right, the controller 37 curves the detection ranges 71 and 72 to the right and expands the detection ranges 71 and 72 to the same side as the leaning direction.

[0117] As shown in Figure 23, in the process of modification 9, if the articulation direction and the turning direction of the work machine 1 are opposite, and the leaning direction is the same as the articulation direction, the controller 37 curves the detection ranges 71 and 72 according to the turning radius of the work machine 1 corresponding to the articulation angle θa, steering angle θs, and leaning angle θl, expands the reference ranges 73 and 74 in the left and right directions according to the articulation angle θa, and expands the detection ranges 71 and 72 on the same side as the leaning direction.

[0118] For example, as shown in Figure 23, when the articulation direction is to the left, the rotation direction of the work machine 1 is to the right, and the leaning direction is to the left, the controller 37 expands the first detection range 71 to the right by an increment La in the articulated state from the first reference range 73, expands the first detection range 71 to the left by an increment Ll in the leaning state from the first reference range 73, and also curves the first detection range 71 to the right. In addition, the controller 37 expands the second detection range 72 to the left by an increment La from the second reference range 74, expands the second detection range 72 to the left by an increment Ll from the second reference range 74, and also curves the second detection range 72 to the right. In this case, the width Lall of the detection ranges 71 and 72 is expressed by the above-mentioned equation (6).

[0119] Although not shown in the diagram, if the articulation direction is to the right, the rotation direction of the work machine 1 is to the left, and the leaning direction is to the right, the controller 37 expands the first detection range 71 to the left by an increment La from the first reference range 73, expands the first detection range 71 to the right by an increment Ll from the first reference range 73, and also curves the first detection range 71 to the left. In addition, the controller 37 expands the second detection range 72 to the right by an increment La from the second reference range 74, increases the second detection range 72 to the right by an increment Ll from the second reference range 74, and also curves the second detection range 72 to the left.

[0120] However, as shown in Figure 24, in the process of modification 9, if the articulation direction and the rotation direction of the work machine 1 are opposite, and the leaning direction is opposite to the articulation direction, the detection range 71,72 is not expanded by the increment Ll during leaning. In this case, the width Lall of the detection range 71,72 is expressed by the above-mentioned equation (4).

[0121] In the work machine 1 according to the embodiment described above, the detection ranges 71 and 72 for objects around the work machine 1 are set according to the articulation angle θa, the leaning angle θl, and the steering angle θs. This makes it possible to appropriately determine whether or not an object is present around the work machine 1.

[0122] Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications are possible without departing from the spirit of the invention.

[0123] The configuration of the work machine 1 is not limited to those described above and may be changed. For example, the configuration of the work machine 5 may be changed. Part of the control system of the work machine 1 may be located outside the work machine 1. For example, the various operating members 46-50 and the output device 63 of the work machine 1 may be located outside the work machine 1.

[0124] The controller 37 may be composed of multiple controllers. The processing described above may be distributed and executed across multiple controllers. Some of the multiple controllers may be located outside the work machine 1.

[0125] The processing when an object is detected within the detection ranges 71 and 72 is not limited to that of the above embodiment and may be modified. For example, when an object is detected within the detection ranges 71 and 72, the controller 37 may perform processing such as stopping the work machine 3 and / or the vehicle body 2, or restricting its operation.

[0126] The process for setting the detection ranges 71 and 72 is not limited to that of the above embodiment and may be modified. The controller 37 may set the detection range to either the front or rear of the vehicle body 2. The controller 37 may set the first detection range 71 in front of the vehicle body 2 when the work machine 1 is moving forward. The controller 37 may set the second detection range 72 behind the vehicle body 2 when the work machine 1 is moving backward.

[0127] The thresholds for the articulate angle θa, steering angle θs, and leaning angle θl used to determine whether to process changes in the detection ranges 71 and 72 are not limited to 0 degrees, but may be other values. For example, the threshold for the articulate angle θa may be a small value such that the work machine 1 can be considered to be in a straight line. The threshold for the steering angle θs may be a small value such that the work machine 1 can be considered not to be steering. The threshold for the leaning angle θl may be a small value such that the work machine 1 can be considered not to be leaning. Changes to the detection ranges 71 and 72 according to the leaning direction may be omitted.

[0128] The controller 37 may add an arbitrary margin width to the width Lall of the detection ranges 71 and 72 described above, taking into account the detection error. For example, as shown in Figure 25, the controller 37 may set the detection ranges 71 and 72 by adding a margin width Lt to the left and right of the reference ranges 73 and 74. Similarly, for the detection ranges 71 and 72 determined by the processes of modification 1 to modification 9 described above, a margin width Lt may be added to the left and right of the detection ranges 71 and 72, respectively.

[0129] In the above embodiment, the front and rear widths of the vehicle body 2 are the same, but the front and rear widths of the vehicle body 2 may be different. In that case, the controller 37 may use the front width as the width of the first reference range 73 to calculate the width of the first detection range 71. The controller 37 may also use the rear width as the width of the second reference range 74 to calculate the width of the second detection range 72. [Industrial applicability]

[0130] According to the present invention, it is possible to appropriately determine whether or not an object is present around a work machine. [Explanation of symbols]

[0131] 2: Body, 3A, 3B: Driving wheels, 11: Front frame, 12: Rear frame, 27, 28: Articulated actuators, 37: Controller, 41A, 41B: Steering actuators, 51: Steering angle sensor, 52: Articulated angle sensor, 53: Leaning angle sensor, 60: Leaning actuator, 61, 62: Object sensors, 71, 72: Detection range, 73, 74: Reference range, θa: Articulated angle, θl: Leaning angle, θs: Steering angle

Claims

1. It is a work machine, A vehicle body including a rear frame and a front frame connected to the rear frame so as to be rotatable from side to side, The running wheels supported by the vehicle body, A steering actuator that steers the aforementioned driving wheels left and right, An articulated actuator that changes the articulation angle between the rear frame and the front frame, A steering angle sensor for detecting the steering angle of the aforementioned driving wheels, The articulation angle sensor for detecting the articulation angle, An object sensor that detects objects around the aforementioned work machine and outputs a signal indicating the presence or absence of the object, A controller that sets a detection range around the aforementioned work machine and determines the presence or absence of the object within the detection range based on the signal from the object sensor, Equipped with, The aforementioned controller, The detection range is set according to the steering angle and the articulation angle. Based on the width of the vehicle body, a reference range for the detection range is set. If the direction of the articulation angle and the rotation direction of the work machine are opposite, the detection range is expanded from the reference range in the left-right direction according to the articulation angle. Agricultural machinery.

2. It is a work machine, A vehicle body including a rear frame and a front frame connected to the rear frame so as to be rotatable from side to side, The running wheels supported by the vehicle body, A steering actuator that steers the aforementioned driving wheels left and right, An articulated actuator that changes the articulation angle between the rear frame and the front frame, A steering angle sensor for detecting the steering angle of the aforementioned driving wheels, The articulation angle sensor for detecting the articulation angle, A leaning actuator that changes the leaning angle of the aforementioned running wheels, A leaning angle sensor for detecting the leaning angle, An object sensor that detects objects around the aforementioned work machine and outputs a signal indicating the presence or absence of the object, A controller that sets a detection range around the aforementioned work machine and determines the presence or absence of the object within the detection range based on the signal from the object sensor, Equipped with, The aforementioned controller, The detection range is set according to the steering angle and the articulation angle. Based on the width of the vehicle body, a reference range for the detection range is set. In the left-right direction, the detection range is expanded from the reference range to the same side as the direction in which the running wheel is leaning. Agricultural machinery.

3. When the work machine rotates according to the articulation angle, the controller curves the detection range according to the rotation radius of the work machine corresponding to the articulation angle. The work machine according to claim 1 or 2.

4. When the detection range is set in front of the front frame, the controller expands the detection range from the reference range to the same side as the rear frame relative to the front frame in the left-right direction. The work machine according to claim 1.

5. When the detection range is set to the rear of the rear frame, the controller expands the detection range from the reference range to the same side of the rear frame as the front frame in the left-right direction. The work machine according to claim 1.

6. The controller does not expand the detection range in accordance with the leaning angle if the rotation direction of the work machine and the direction of the articulate angle are opposite, and the direction in which the traveling wheels are leaning coincides with the rotation direction of the work machine. The working machine according to claim 2.

7. A method for controlling a work machine, wherein the work machine includes a body comprising a rear frame and a front frame rotatably connected to the rear frame, running wheels supported by the body, a steering actuator for steering the running wheels left and right, and an articulating actuator for changing the articulation angle between the rear frame and the front frame, and the method is The steering angle of the aforementioned driving wheels is detected, The articulation angle is detected, Receiving a signal indicating the presence or absence of objects in the vicinity of the aforementioned work machine, A detection range is set around the work machine according to the steering angle and the articulation angle, Based on the aforementioned signal, the presence or absence of the object within the detection range is determined, Based on the width of the vehicle body, a reference range is set for the detection range, If the direction of the articulation angle and the rotation direction of the work machine are opposite, the detection range is expanded from the reference range in the left-right direction according to the articulation angle. A method for providing this.

8. A method for controlling a work machine, wherein the work machine includes a body comprising a rear frame and a front frame rotatably connected to the rear frame, running wheels supported by the body, a steering actuator for steering the running wheels left and right, an articulating actuator for changing the articulation angle between the rear frame and the front frame, and a leaning actuator for changing the leaning angle of the running wheels, and the method is The steering angle of the aforementioned driving wheels is detected, The articulation angle is detected, Receiving a signal indicating the presence or absence of objects in the vicinity of the aforementioned work machine, A detection range is set around the work machine according to the steering angle and the articulation angle, Based on the aforementioned signal, the presence or absence of the object within the detection range is determined, Based on the width of the vehicle body, a reference range is set for the detection range, The detection of the leaning angle, In the left-right direction, the detection range is expanded from the reference range to the same side as the direction in which the running wheel is leaning. A method for providing this.

9. If the work machine rotates according to the articulation angle, the detection range is further curved according to the rotation radius of the work machine corresponding to the articulation angle. The method according to claim 7 or 8.

10. When the detection range is set in front of the front frame, the detection range is further expanded from the reference range on the same side as the rear frame relative to the front frame in the left-right direction. The method according to claim 7.

11. When the detection range is set to the rear of the rear frame, the detection range is further expanded from the reference range on the same side as the front frame relative to the rear frame in the left-right direction. The method according to claim 7.

12. The system further includes the provision that, if the rotation direction of the work machine and the direction of the articulate angle are opposite, and the direction in which the traveling wheels are leaning coincides with the rotation direction of the work machine, the detection range corresponding to the leaning angle is not expanded. The method according to claim 8.

13. A system for controlling a work machine, wherein the work machine includes a body comprising a rear frame and a front frame rotatably connected to the rear frame, running wheels supported by the body, steering actuators for steering the running wheels left and right, and articulating actuators for changing the articulation angle between the rear frame and the front frame, and the system is A steering angle sensor for detecting the steering angle of the aforementioned driving wheels, The articulation angle sensor for detecting the articulation angle, An object sensor that detects objects around the aforementioned work machine and outputs a signal indicating the presence or absence of the object, A controller that sets a detection range around the aforementioned work machine and determines the presence or absence of the object within the detection range based on the signal from the object sensor, Equipped with, The aforementioned controller, The detection range is set according to the steering angle and the articulation angle. Based on the width of the vehicle body, a reference range for the detection range is set. If the direction of the articulation angle and the rotation direction of the work machine are opposite, the detection range is expanded from the reference range in the left-right direction according to the articulation angle. system.

14. A system for controlling a work machine, wherein the work machine includes a body comprising a rear frame and a front frame rotatably connected to the rear frame, running wheels supported by the body, steering actuators for steering the running wheels left and right, and articulating actuators for changing the articulation angle between the rear frame and the front frame, and the system is A steering angle sensor for detecting the steering angle of the aforementioned driving wheels, The articulation angle sensor for detecting the articulation angle, A leaning actuator that changes the leaning angle of the aforementioned running wheels, A leaning angle sensor for detecting the leaning angle, An object sensor that detects objects around the aforementioned work machine and outputs a signal indicating the presence or absence of the object, A controller that sets a detection range around the aforementioned work machine and determines the presence or absence of the object within the detection range based on the signal from the object sensor, Equipped with, The aforementioned controller, The detection range is set according to the steering angle and the articulation angle. Based on the width of the vehicle body, a reference range for the detection range is set. In the left-right direction, the detection range is expanded from the reference range to the same side as the direction in which the running wheel is leaning. system.

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