Work vehicle

Abstract

To provide a work vehicle that can more reliably detect an object to be avoided on a travel route.SOLUTION: A work vehicle 100 comprises first external sensors 131, a second external sensor 132, and a detection direction adjustment device. The first external sensors 131 are arranged on both sides of a work machine 120 of a front frame 111, and detects at least a position of an object AO to be avoided in a predetermined area DA1 through which a pair of front wheels 118 in front of the front frame 111 pass. The second external sensor 132 is attached to a rear frame 112 at a position above the first external sensors 131, and detects at least a size of the object AO to be avoided detected by the first external sensors 131. The detection direction adjustment device adjusts a detection direction of the second external sensor 132 toward the object AO to be avoided based on the position of the object AO to be avoided detected by the first external sensors 131.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present disclosure relates to a work vehicle.

Background Art

[0002] Conventionally, a collision mitigation system and method for a work vehicle have been known (Patent Document 1 below). The articulated work vehicle described in Patent Document 1 includes a front frame having a first wheel pair, a rear frame having a second wheel pair, a hitch that bendably couples the front frame to the rear frame, and a power train configured to drive at least the second wheel pair. Further, the work vehicle includes a steering system, the first sensor system, a second sensor system, a third sensor system, and a real-time processing circuit (Claim 1, etc.).

[0003] The steering system is configured to provide controlled articulation of the front frame relative to the rear frame about the hitch based on a driver's control input. The first sensor system is configured to detect an object around the articulated work vehicle. The second sensor system is configured to detect a real-time articulation angle of the front frame relative to the rear frame. The third sensor system is configured to sense the real-time rotation of the first and second wheel pairs.

[0004] The real-time processing circuit is electrically connected to the steering system, the first sensor system, the second sensor system, and the third sensor system. Further, the real-time processing circuit determines a safety zone around the articulated work vehicle based on a signal from the first sensor system corresponding to a detected object around the articulated vehicle.

[0005] Further, the real-time processing circuit determines the position and velocity of one or more peripheral points on the articulated work vehicle based on signals from the second sensor system and the third sensor system. Further, the real-time processing circuit receives a control input from the driver and applies a restriction to the control input of the driver when it is predicted that the peripheral points of the articulated work vehicle are within a predetermined distance from the nearest end of the safety zone.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] In the above Patent Document 1, as the first sensor system, a 360° camera or a plurality of cameras sufficient to provide a 360° panoramic view is exemplified (paragraph 0024). However, in a work vehicle, for example, due to the operation of a working machine attached to the front frame or the bending of the front frame with respect to the rear frame, the blind spot of the sensor system changes, and there is a possibility that an avoidance target on the travel route that requires avoidance by the work vehicle cannot be detected.

[0008] The present disclosure provides a work vehicle capable of more reliably detecting an avoidance target on a travel route.

Means for Solving the Problems

[0009] One aspect of the present disclosure includes a front frame having a pair of front wheels, a rear frame having a pair of rear wheels, a connecting pin that flexibly connects the front frame to the rear frame, a driving device that drives at least the pair of rear wheels, a steering device that bends the front frame with respect to the rear frame about the connecting pin, a working machine attached to the front frame, a first external sensor provided on the front frame so as to be positioned on both sides of the working machine, and configured to detect a position of an avoidance target in a predetermined area through which the pair of front wheels in front of the front frame are about to pass, a second external sensor attached on the rear frame side at a position higher than the first external sensor and configured to detect at least a size of the avoidance target detected by the first external sensor, a detection direction adjustment device configured to adjust a detection direction of the second external sensor in a direction of the avoidance target based on the position of the avoidance target detected by the first external sensor, and a control device configured to control an operation of at least one of the driving device or the steering device based on the size of the avoidance target detected by the second external sensor based on the detection direction adjusted by the detection direction adjustment device. The work vehicle is characterized by including the above components.

Advantages of the Invention

[0010] According to the above aspect of the present disclosure, it is possible to provide a work vehicle capable of more reliably detecting an avoidance target on a travel route.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0012] Hereinafter, embodiments of the work vehicle according to the present disclosure will be described with reference to the drawings.

[0013] FIG. 1 is a side view showing an embodiment of a work vehicle according to the present disclosure. FIG. 2 is a block diagram of the work vehicle 100 of FIG. 1. In the following description, each part of the work vehicle 100 may be described based on a rectangular coordinate system composed of an X-axis parallel to the front-rear direction of the work vehicle 100, a Y-axis parallel to the width direction of the work vehicle 100, and a Z-axis parallel to the height direction of the work vehicle 100.

[0014] The work vehicle 100 of the present embodiment is, for example, a wheel loader that performs predetermined work at various work sites such as mining areas, landfills, quarries, and construction sites. The predetermined work performed by the work vehicle 100 includes, for example, leveling work, excavation work, slope formation work, transportation work of soil, sand, crushed stone, minerals, etc., and loading work. Note that the work vehicle 100 is not limited to a wheel loader and may be other work vehicles.

[0015] The work vehicle 100 includes, for example, a front frame 111, a rear frame 112, a connecting pin 113, a drive device 114, a steering device 115, a work implement 120, a first external sensor 131, a second external sensor 132, a detection direction adjustment device 133, and a control device 140. Further, the work vehicle 100 includes, for example, a vehicle state sensor 134, an operation device 135, a braking device 116, and a notification device 117.

[0016] The front frame 111 has a pair of front wheels 118, and the rear frame 112 has a pair of rear wheels 119. The connecting pin 113 connects the front frame 111 to the rear frame 112 so as to be bendable. The front frame 111, the rear frame 112, and the connecting pin 113 constitute the vehicle body 110 of the work vehicle 100.

[0017] The drive device 114 includes, for example, an engine mounted on the rear frame 112 and a hydrostatic continuously variable transmission (HST), and drives at least a pair of rear wheels 119. Further, the drive device 114 may drive, for example, a pair of front wheels 118. The drive device 114 includes, for example, a hydraulic device and drives the steering device 115 and the work implement 120 described later. Further, the hydraulic device of the drive device 114 may be configured to generate the braking force of the braking device 116, for example.

[0018] The steering device 115 bends the front frame 111 with respect to the rear frame 112 around the connecting pin 113. The steering device 115 has, for example, a pair of steering cylinders driven by the drive device 114. Each steering cylinder has a piston rod and a cylinder tube connected to the front frame 111 and the rear frame 112, respectively, and bends the front frame 111 with respect to the rear frame 112 around the connecting pin 113 by extending and retracting the piston rod.

[0019] The braking device 116 applies a braking force to a pair of front wheels 118 and a pair of rear wheels 119 based on a control signal from a control device 140 according to the operation of a brake pedal included in the operation device 135, for example, and decelerates or stops the work vehicle 100. The notification device 117 is installed, for example, in the cabin 112a of the rear frame 112 and notifies the operator of the work vehicle 100 of information regarding the work vehicle 100. The notification device 117 includes, for example, a display device, a display lamp, a speaker, an alarm, a buzzer, an instrument, and the like.

[0020] The work implement 120 is attached to the front frame 111 and extends forward of the work vehicle 100. The work implement 120 includes, for example, a pair of left and right lift arms 121, a bucket 122, a bell crank 123, and a bucket link 124. Further, the work implement 120 includes, for example, a lift arm cylinder 125 and a bucket cylinder 126.

[0021] The lift arm 121 is rotatably attached to the front frame 111 of the vehicle body 110. The central portion in the longitudinal direction of the lift arm 121 is rotatably connected to the tip of the piston rod of the lift arm cylinder 125. The base end of the cylinder tube on the side opposite to the piston rod of the lift arm cylinder 125 is rotatably connected to the front frame 111. The lift arm cylinder 125 is driven by the drive device 114 to expand and contract, thereby rotating the lift arm 121 of the working machine 120 up and down.

[0022] The bucket 122 is rotatably attached to the tip of the lift arm 121 opposite to the base end attached to the vehicle body 110. One end of the bucket link 124 is rotatably connected to the bottom of the bucket 122, and the other end of the bucket link 124 is rotatably connected to one end of the bell crank 123.

[0023] The central portion in the longitudinal direction of the bell crank 123 is rotatably connected to, for example, a support portion extending from a connecting portion connecting a pair of left and right lift arms 121 toward the bucket 122. The end of the bell crank 123 opposite to the end connected to the bucket link 124 is rotatably connected to the tip of the piston rod of the bucket cylinder 126.

[0024] The base end of the cylinder tube on the side opposite to the piston rod of the bucket cylinder 126 is rotatably connected to the front frame 111. The bucket cylinder 126 is driven by the drive device 114 to expand and contract, thereby rotating the bucket 122 up and down via the bell crank 123 and the bucket link 124.

[0025] The first external sensor 131 is disposed on both sides of the working machine 120 of the front frame 111, and detects at least the position of the avoidance target AO in a predetermined area DA1 through which a pair of front wheels 118 in front of the front frame 111 pass (see FIG. 4). In the example shown in FIGS. 1 and 4, the first external sensor 131 is fixed, for example, to the upper side of the headlight 111a that protrudes outward in the width direction of the front frame 111 from the side portion of the front frame 111. Note that the first external sensor 131 may be fixed to a bracket that protrudes outward in the width direction from the side portion of the front frame 111 separately from the headlight 111a, for example.

[0026] As the first external sensor 131, for example, a millimeter-wave radar, a lidar, a monocular camera, or a stereo camera can be used. The predetermined area DA1 in which the first external sensor 131 detects the position of the avoidance target AO depends on the type of the sensor, but includes at least the area through which the pair of front wheels 118 pass when the work vehicle 100 travels straight. The avoidance target AO detected by the first external sensor 131 is, for example, an obstacle that can cause a factor for reducing the stability of the work vehicle 100, and includes unevenness on the ground, rocks, falling objects, trees, pedestrians, animals, vehicles, machines, and other objects.

[0027] The first external sensor 131 detects at least the position of the avoidance target AO. Specifically, the first external sensor 131 detects, for example, the distance, direction, size, type, etc. of an object existing in the predetermined area DA1, and calculates the position of the avoidance target AO. The first external sensor 131 is connected to the control device 140 via a wireless communication line or a wired communication line, and outputs the detection result of the object in the predetermined area DA1 to the control device 140.

[0028] The second external sensor 132 is attached at a position higher than the first external sensor 131 of the rear frame 112, and detects at least the size of the avoidance target AO detected by the first external sensor 131. The second external sensor 132 is attached, for example, at the center in the width direction on the front side of the upper part of the cabin 112a provided on the rear frame 112. As the second external sensor 132, for example, similar to the first external sensor 131, a millimeter wave radar, a lidar, a monocular camera, or a stereo camera can be used, or these can be used in combination.

[0029] The detection direction adjustment device 133 readjusts the detection direction of the second external sensor 132 to the direction of the avoidance target AO based on the position of the avoidance target AO detected by the first external sensor 131. The detection direction adjustment device 133 is composed of, for example, a motor, a gear, an angle sensor, etc. incorporated in the second external sensor 132. The detection direction adjustment device 133 changes the detection direction of the second external sensor 132, for example, by rotating the sensing part of the second external sensor 132 around a rotation axis parallel to the height direction of the work vehicle 100 or a rotation axis parallel to the width direction of the work vehicle 100. For example, if the second external sensor 132 is a monocular camera, it readjusts so that the avoidance target AO captured by the monocular camera becomes the center of the detection image.

[0030] The vehicle state sensor 134 detects vehicle information including the speed of the work vehicle 100 and the inclination angle of the front frame 111 with respect to the rear frame 112, and outputs the detected vehicle information to the control device 140. The vehicle state sensor 134 includes at least a speed sensor that detects the speed of the work vehicle 100 and an angle sensor that detects vehicle information including the inclination angle of the front frame 111 with respect to the rear frame 112.

[0031] In addition, the vehicle state sensor 134 may include at least one of an acceleration sensor, a receiver of a Global Navigation Satellite System (GNSS), an engine rotation sensor, or an attitude sensor of the working machine 120. In this case, in addition to the speed of the work vehicle 100 and the inclination angle, the vehicle state sensor 134 detects, for example, at least one of the acceleration, position, engine speed of the work vehicle 100, or the attitude of the working machine 120. Note that, as the attitude sensor of the working machine 120, an angle sensor provided at a joint of the working machine 120, a stroke sensor of the lift arm cylinder 125 and the bucket cylinder 126, or the like can be used.

[0032] The operation device 135 is installed, for example, in the cab 112a of the rear frame 112, receives an operation by the operator of the work vehicle 100, and outputs an operation signal corresponding to the operation to the control device 140. The operation device 135 includes, for example, at least one of operation pedals such as an accelerator pedal and a brake pedal, a steering wheel, an operation lever, an operation switch, an operation button, a touch panel, or a voice recognition device.

[0033] The control device 140 controls the operations of the aforementioned drive device 114, steering device 115, and detection direction adjustment device 133. The control device 140 is, for example, an electronic control unit (ECU) installed in the lower part or the rear part of the cab 112a where the operator of the rear frame 112 rides, and is composed of one or more microcontrollers. The microcontroller is composed of, for example, an input / output device, a central processing unit (CPU), a memory, and a timer.

[0034] The control device 140 has, for example, an avoidance target extraction unit 141, an avoidance area calculation unit 142, and a detection direction calculation unit 143. In addition, the control device 140 has, for example, a sensor diagnosis unit 144, a vehicle state acquisition unit 145, a stability calculation unit 146, an operation mode acquisition unit 147, an operation determination unit 148, and an operation control unit 149.

[0035] Each part of the control device 140 shown in FIG. 2 is a functional block representing various functions of the control device 140. Each function of the control device 140 is realized, for example, by the CPU of the control device 140 executing various programs stored in the memory. Note that each function of the control device 140 can also be realized by one ECU respectively, and a plurality of functions can also be realized by one ECU.

[0036] Hereinafter, the operation of the work vehicle 100 of the present embodiment will be described. FIG. 3 is a flowchart for explaining the operation of the work vehicle 100 of FIGS. 1 and 2. FIG. 4 is a plan view for explaining the operation of the work vehicle 100 of FIGS. 1 and 2.

[0037] For example, when the work vehicle 100 starts to run, the control device 140 starts the processing flow shown in FIG. 3. When the control device 140 starts the processing flow shown in FIG. 3, it first executes a process P1 of acquiring first external information. In the process P1, the avoidance target extraction unit 141 of the control device 140 shown in FIG. 2 acquires the first external information D1 output from the first external sensors 131 attached to both sides of the work implement 120 of the previous frame 111.

[0038] As shown in FIG. 4, the first external sensor 131 detects the position of an object in a predetermined area DA1 including at least the area through which a pair of front wheels 118 in front of the running work vehicle 100 pass, and outputs it to the control device 140. Specifically, the first external sensor 131 calculates the relative position of the object in the predetermined area DA1 by detecting, for example, the distance and direction of the object in the predetermined area DA1, and outputs it to the control device 140. The avoidance target extraction unit 141 acquires the position of the object in the predetermined area DA1 output from the first external sensor 131 as the first external information D1.

[0039] In addition, the first external sensor 131 may detect the size, shape, and type of an object existing in the predetermined area DA1. In the example shown in FIG. 4, the first external sensor 131 detects, for example, the ground, unevenness, rocks, fallen objects, trees, pedestrians (including workers working around the vehicle), animals, vehicles, machines, and other objects existing in the predetermined area DA1, and outputs the size, shape, and type of the detected object to the control device 140. In this case, the avoidance target extraction unit 141 acquires, as the first external information D1, for example, the position, size, shape, and type of the object in the predetermined area DA1 output from the first external sensor 131.

[0040] Next, the control device 140 executes, for example, a process P2 of extracting an avoidance target AO. In the process P2, the avoidance target extraction unit 141 of the control device 140 extracts an avoidance target AO that the work vehicle 100 should avoid from the first external information D1 acquired in the process P1. In this process P2, the avoidance target extraction unit 141 functions as, for example, a selector, a filter, and a sampler that extracts the avoidance target AO from the first external information D1.

[0041] In this process P2, the avoidance target extraction unit 141 extracts, as the avoidance target AO, an object that is predicted to be present at a position where a pair of front wheels 118 will pass and is closer than a predetermined distance based on the position of the object included in the first external information D1. Further, in the process P2, the avoidance target extraction unit 141 may calculate the height of the object from the ground included in the first external information D1, and extract, as the avoidance target AO, an object whose calculated height is equal to or greater than a predetermined threshold value.

[0042] Also, in the process P2, the avoidance target extraction unit 141 may extract the avoidance target AO based on the size and shape of the object included in the first external information D1 in addition to the height of the object. The avoidance target extraction unit 141 outputs the information D2 of the extracted avoidance target AO to, for example, the avoidance area calculation unit 142 and the stability calculation unit 146.

[0043] Next, the control device 140 executes a process P3 for determining the presence or absence of the avoidance target AO. In this process P3, the avoidance area calculation unit 142 and the stability calculation unit 146 determine that there is an avoidance target AO (YES) if there is an input of information D2 from the avoidance target extraction unit 141, and determine that there is no avoidance target AO (NO) if there is no input of information D2.

[0044] In the process P3, when it is determined that there is an avoidance target AO (YES), the control device 140 executes a process P4 for calculating the avoidance area and stability. In this process P4, the avoidance area calculation unit 142 calculates an avoidance area including the avoidance target AO based on the information D2 of the avoidance target AO input from the avoidance target extraction unit 141. The avoidance area is, for example, an area including a range where the position of the avoidance target AO and the distance from the avoidance target AO are equal to or less than a predetermined threshold value, and is an area where the avoidance target AO exists. The avoidance area calculation unit 142 outputs, for example, the calculated information D3 of the avoidance area to the detection direction calculation unit 143 and the operation determination unit 148.

[0045] Also, in the process P4, the stability calculation unit 146 calculates the stability when the work vehicle 100 passes over the avoidance target AO based on the information D2 of the avoidance target AO input from the avoidance target extraction unit 141. The stability calculation unit 146 calculates the stability of the work vehicle 100 based on, for example, the information D2 of the avoidance target AO and the vehicle information D5 including the speed of the work vehicle 100 input from the vehicle state acquisition unit 145. Here, the vehicle state acquisition unit 145 acquires, for example, a detection signal D4 from the vehicle state sensor 134, calculates vehicle information D5 including the speed of the work vehicle 100 based on the detection signal D4, and outputs it to the stability calculation unit 146.

[0046] The stability calculation unit 146 calculates, for example, the stability of the work vehicle 100 according to the height of the avoidance target AO from the ground. Specifically, the stability of the work vehicle 100 calculated by the stability calculation unit 146 decreases as the height of the avoidance target AO from the ground increases, and increases as the height of the avoidance target AO from the ground decreases. Further, the stability calculation unit 146 calculates, for example, the stability of the work vehicle 100 according to the speed of the work vehicle 100. Specifically, the stability of the work vehicle 100 calculated by the stability calculation unit 146 decreases as the speed of the work vehicle 100 increases, and increases as the speed of the work vehicle 100 decreases.

[0047] Further, the stability calculation unit 146 may calculate the stability of the work vehicle 100 according to both the height of the avoidance target AO from the ground and the speed of the work vehicle 100. Further, the stability calculation unit 146 may calculate the stability of the work vehicle 100 according to the size and shape of the avoidance target AO. The stability calculation unit 146 outputs the calculated stability D6 of the work vehicle 100 to the operation determination unit 148.

[0048] Next, the control device 140 executes a process P5 of calculating the detection direction of the second external sensor 132. In this process P5, the detection direction calculation unit 143 calculates, for example, the angle of the detection direction of the second external sensor 132 based on the avoidance area information D3 acquired from the avoidance area calculation unit 142.

[0049] FIG. 5 is a conceptual diagram for explaining the operation of the second external sensor 132 of the work vehicle 100 in FIGS. 1 and 2. In the process P5 of calculating the detection direction of the second external sensor 132, the detection direction calculation unit 143 calculates, for example, the height H from the ground G to the second external sensor 132 based on the information on the mounting position of the second external sensor 132 stored in the non-volatile memory of the control device 140.

[0050] Furthermore, based on the information D3 of the avoidance area including the avoidance target AO acquired from the avoidance area calculation unit 142, the detection direction calculation unit 143 calculates the angles θ1, θ2, and θ3 of the second external sensor 132 for readjusting the detection direction of the second external sensor 132 to each avoidance area. In the example shown in FIG. 5, when a plurality of avoidance targets AO are detected by the first external sensor 131, the detection direction calculation unit 143 sequentially calculates the angles θ1, θ2, and θ3 from the detection area closer to the work vehicle 100.

[0051] Note that in FIG. 5, the angles θ1, θ2, and θ3 of the detection direction of the second external sensor 132 with respect to the height direction (Z-axis direction) of the work vehicle 100 are shown. However, in process P5, the detection direction calculation unit 143 can similarly calculate, for example, the angle of the detection direction of the second external sensor 132 with respect to the front-rear direction (X-axis direction) of the work vehicle 100. The detection direction calculation unit 143 outputs the calculated angle D7 of the detection direction of the second external sensor 132 to the operation determination unit 148.

[0052] Next, the control device 140 executes a process P6 of acquiring the second external information D9 from the second external sensor 132. In this process P6, based on the angle D7 of the detection direction of the second external sensor 132 acquired from the detection direction calculation unit 143, for example, the operation determination unit 148 calculates the rotation angle of the second external sensor 132 by the detection direction adjustment device 133. Furthermore, the operation determination unit 148 outputs the calculated rotation angle of the second external sensor 132 to the operation control unit 149 as operation information D8.

[0053] The operation control unit 149 outputs a control signal based on the rotation angle of the second external sensor 132, which is the operation information D8 input from the operation determination unit 148, to the detection direction adjustment device 133 to control the operation of the detection direction adjustment device 133. As a result, as shown in FIG. 5, the detection direction adjustment device 133 readjusts the detection direction of the second external sensor 132 to the avoidance area including the avoidance target AO. Thereafter, the avoidance target extraction unit 141 acquires the second external information D9 output from the second external sensor 132.

[0054] As shown in FIG. 4, the second external sensor 132 is attached to the upper part of the cabin 112a of the rear frame 112, and detects the size of the avoidance target AO detected by the first external sensor 131 in a predetermined area DA2 in front of the work vehicle 100. Note that the second external sensor 132 may detect not only the size of the avoidance target AO, but also the distance and direction from the second external sensor 132 to the avoidance target AO, the type of the avoidance target AO, and the like.

[0055] The predetermined area DA2 in which the second external sensor 132 detects the avoidance target AO is wider in the width direction of the work vehicle 100 than the predetermined area DA1 in which the first external sensor 131 detects the avoidance target AO, for example. In the front-rear direction of the work vehicle 100, the width of the predetermined area DA2 in which the second external sensor 132 detects the avoidance target AO changes as shown in FIG. 4 by changing the detection direction by the detection direction adjusting device 133.

[0056] That is, the second external sensor 132 is a dynamic sensor in which the predetermined area DA2 for detecting the avoidance target AO changes according to the operation of the detection direction adjusting device 133. In addition, the avoidance target AO detected by the second external sensor 132 has various sizes and shapes such as a wide avoidance target AO and a narrow avoidance target AO, and includes a moving body that suddenly appears in the area through which the front wheels 118 of the work vehicle 100 pass.

[0057] Next, the control device 140 executes a process P7 of determining whether or not an avoidance target AO exists in the traveling route of the work vehicle 100. In this process P7, the avoidance target extraction unit 141 extracts the avoidance target AO that the work vehicle 100 should avoid based on the second external information D9 acquired from the second external sensor 132. For example, the avoidance target extraction unit 141 extracts an avoidance target AO having a size exceeding a preset threshold value such as height, width, and depth, and outputs the information D2 of the extracted avoidance target AO to the stability calculation unit 146.

[0058] Further, the vehicle state acquisition unit 145 calculates vehicle information D5 based on the detection signal D4 acquired from the vehicle state sensor 134 and outputs it to the stability calculation unit 146. The stability calculation unit 146 determines whether or not the avoidance target AO exists on the traveling route of the work vehicle 100 based on the vehicle information D5 input from the vehicle state acquisition unit 145 and the information D2 of the avoidance target AO input from the avoidance target extraction unit 141.

[0059] When the control device 140 determines that the avoidance target AO does not exist on the traveling route of the work vehicle 100 (process P7: NO), the control device 140 re-executes the process P1 of acquiring the aforementioned first external information D1. Further, when the control device 140 determines that the avoidance target AO exists on the traveling route of the work vehicle 100 (process P7: YES), the control device 140 executes the process P11 of determining the operation of the work vehicle 100.

[0060] On the other hand, in the aforementioned process P3, when the avoidance target AO is not included in the first external information D1 of the first external sensor 131 and there is no input of the information D2 of the avoidance target AO from the avoidance target extraction unit 141 to the avoidance area calculation unit 142 or the like, the control device 140 determines that there is no avoidance target AO (NO). In this case, the control device 140 executes the process P8 of acquiring the second external information.

[0061] In this process P8, the operation determination unit 148 outputs operation information D8 for stopping the detection direction adjustment device 133 at the default position. The operation control unit 149 stops the detection direction adjustment device 133 at the specified position based on the operation information D8 input from the operation determination unit 148 and readjusts the detection direction of the second external sensor 132 to the specified direction. This specified direction may be changed according to the speed of the work vehicle 100 and the stoppable distance, for example, so as to detect a distant avoidance target AO as the speed of the work vehicle 100 increases. The avoidance target extraction unit 141 acquires the second external information D9 from the second external sensor 132.

[0062] Next, the control device 140 executes a process P9 for determining the presence or absence of an object to be avoided. In this process P9, the avoidance target extraction unit 141 extracts an avoidance target AO from the second external information D9 acquired from the second external sensor 132. More specifically, in this process P9, the avoidance target extraction unit 141 executes, for example, the same process as the process performed on the first external information D1 of the first external sensor 131 in the above-described process P2 on the second external information D9 of the second external sensor 132. The avoidance target extraction unit 141 outputs the information D2 of the extracted avoidance target AO to, for example, the avoidance area calculation unit 142 and the stability calculation unit 146.

[0063] In this process P9, the avoidance area calculation unit 142 and the stability calculation unit 146 determine that there is an avoidance target AO (YES) if there is an input of information D2 from the avoidance area calculation unit 142, and determine that there is no avoidance target AO (NO) if there is no input of information D2, in the same manner as in the above-described process P3. In this process P9, when it is determined by the avoidance area calculation unit 142 and the stability calculation unit 146 that there is no avoidance target AO (NO), the control device 140 returns to the process P1 of acquiring the above-described first external information D1.

[0064] On the other hand, in this process P9, when the avoidance area calculation unit 142 and the stability calculation unit 146 determine that there is an avoidance target AO (YES), they execute a process P10 of calculating an avoidance area including the avoidance target AO and the stability of the work vehicle 100 passing through the avoidance target AO, in the same manner as in the above-described process P4. Thereafter, the control device 140 executes a process P11 of determining the operations of the drive device 114, the steering device 115, the braking device 116, and the notification device 117.

[0065] In process P11 for determining the operation of work vehicle 100, stability calculation unit 146 calculates stability D6 of work vehicle 100 based on, for example, vehicle information D5 and information D2 of avoidance target AO, and outputs it to operation determination unit 148. Further, operation device 135 outputs an operation signal D10 based on, for example, the operation of the operator of work vehicle 100 to operation mode acquisition unit 147 and operation determination unit 148. Operation mode acquisition unit 147 acquires operation mode D11 of work vehicle 100 based on vehicle information D5 acquired from vehicle state acquisition unit 145 and operation signal D10 input from operation device 135.

[0066] Here, operation mode D11 of work vehicle 100 includes, for example, control modes of work vehicle 100 such as manual operation mode, automatic control mode, semi-automatic control mode, etc. Further, operation mode D11 of work vehicle 100 includes information regarding the work mode in which work vehicle 100 is operating, such as travel mode, excavation mode, leveling mode, loading mode, etc. Operation mode acquisition unit 147 determines operation mode D11 based on operations of, for example, operation switches, operation levers, operation pedals, etc. included in operation device 135.

[0067] Furthermore, in this process P11, operation determination unit 148 determines the operation of work vehicle 100 based on, for example, stability D6 input from stability calculation unit 146 and operation mode D11 input from operation mode acquisition unit 147. More specifically, operation determination unit 148 controls at least one of drive device 114, steering device 115, or braking device 116 to determine an avoidance operation for avoiding an avoidance area including avoidance target AO when stability D6 of work vehicle 100 is lower than a predetermined threshold value. In this case, operation determination unit 148 may further control notification device 117 to determine a notification operation for notifying the operator of work vehicle 100 of the avoidance operation.

[0068] Here, the avoidance operations of the drive device 114, the steering device 115, or the braking device 116 include operations such as deceleration, stop, turning, change of the traveling route of the work vehicle 100, or input restriction of the operation signal D10 based on the operation of the operation device 135 by the operator. Further, the notification operation of the notification device 117 includes operations such as display by an image display device, voice guidance by a speaker, sounding of a buzzer or an alarm, and lighting of a display lamp, which are targeted at at least one of the stability of the work vehicle 100, the avoidance area, the avoidance target AO, or the avoidance operation.

[0069] Further, for example, when the stability D6 of the work vehicle 100 is equal to or greater than a predetermined threshold value, the operation determination unit 148 determines the operations of the drive device 114, the steering device 115, the braking device 116, and the notification device 117 according to the operation mode D11 input from the operation mode acquisition unit 147. Specifically, for example, when the operation mode D11 is the manual operation mode, the operation determination unit 148 determines the operations of the drive device 114, the steering device 115, the braking device 116, and the notification device 117 based on the operation signal D10 corresponding to the operation of the operation device 135 by the operator of the work vehicle 100. Further, when the operation mode D11 is the automatic control mode or the semi-automatic control mode, the operation determination unit 148 autonomously determines the operations of the drive device 114, the steering device 115, the braking device 116, and the notification device 117.

[0070] Next, the control device 140 executes a process P12 for diagnosing the sensor. In this process P12, the sensor diagnosis unit 144 diagnoses the first external sensor 131 and the second external sensor 132 based on the first external information D1 input from the first external sensor 131 and the second external information D9 input from the second external sensor 132. Specifically, the sensor diagnosis unit 144 diagnoses the first external information D1, the second external information D9, and the reliability of the data interface. The sensor diagnosis unit 144 outputs the diagnosis result D12 to the operation determination unit 148.

[0071] Next, the control device 140 executes a process P13 for diagnosing the operation of the work vehicle 100. In this process P13, based on the diagnosis result D12 input from the sensor diagnosis unit 144, the operation determination unit 148 diagnoses the operation of the work vehicle 100 determined in the above-mentioned process P11. For example, when there is a problem with the diagnosis result D12 of the first external sensor 131 and the second external sensor 132, the operation determination unit 148 changes the operation determined in the above-mentioned process P11, determines an emergency operation such as an emergency stop, and outputs it as operation information D8 to the operation control unit 149. When there is no problem with the diagnosis result D12, the operation determination unit 148 maintains the operation determined in the above-mentioned process P11 and outputs it as operation information D8 to the operation control unit 149.

[0072] Next, the control device 140 performs a process P14 for executing the operation of the work vehicle 100 determined by the operation determination unit 148. In this process P14, the operation control unit 149 outputs a control signal corresponding to the operation information D8 input from the operation determination unit 148 to the drive device 114, the steering device 115, the braking device 116, and the notification device 117. As a result, the work vehicle 100 can execute an avoidance operation for avoiding an avoidance area including the avoidance target AO, a notification operation for notifying the operator of the avoidance operation, an emergency operation when the reliability of the first external sensor 131 and the second external sensor 132 decreases, and the like.

[0073] Also, while it is determined in the above-mentioned process P7 or process P9 that there is no avoidance target AO (NO), the operation determination unit 148 determines an operation according to the operation signal D10 based on the operation of the operator's operation device 135 and outputs it as operation information D8 to the operation control unit 149. Therefore, when there is no avoidance target AO on the traveling route of the work vehicle 100, the control device 140 controls the drive device 114, the steering device 115, the braking device 116, and the notification device 117 according to the operation of the operator's operation device 135.

[0074] Further, the control device 140 may monitor the operation of the avoidance target extraction unit 141 that functions as a selector, a filter, and a sampler. When the avoidance target extraction unit 141 is not operating normally due to some malfunction, the operation determination unit 148 determines an operation to display the malfunction on the notification device 117 and outputs operation information D8, and the operation control unit 149 causes the notification device 117 to display the malfunction based on the input operation information D8.

[0075] As is clear from the above description, the work vehicle 100 of the present embodiment has the following configuration. The work vehicle 100 includes a front frame 111 having a pair of front wheels 118, a rear frame 112 having a pair of rear wheels 119, and a connecting pin 113 that connects the front frame 111 to the rear frame 112 so as to be bendable. Further, the work vehicle 100 includes a drive device 114 that drives at least a pair of rear wheels 119, a steering device 115 that bends the front frame 111 with respect to the rear frame 112 about the connecting pin 113, and a work implement 120 attached to the front frame 111. Furthermore, the work vehicle 100 includes a first external sensor 131, a second external sensor 132, a detection direction adjustment device 133, and a control device 140. The first external sensor 131 is provided on the front frame 111 so as to be positioned on both sides of the work implement 120, and detects the position of the avoidance target AO when the avoidance target AO exists in a predetermined region DA1 where a pair of front wheels 118 in front of the front frame 111 are about to pass. The second external sensor 132 is attached on the rear frame 112 side at a position higher than the first external sensor 131, and detects at least the size of the avoidance target AO detected by the first external sensor 131. The detection direction adjustment device 133 adjusts the detection direction of the second external sensor 132 in the direction of the avoidance target AO based on the position of the avoidance target AO detected by the first external sensor 131. The control device 140 controls the operation of at least one of the drive device 114 or the steering device 115 based on the detection direction adjusted by the detection direction adjustment device 133.

[0076] As described above, in the work vehicle 100 of the present embodiment, since the first external sensor 131 is disposed on both sides of the working machine 120 of the front frame 111, the first external sensor 131 can detect an object in a predetermined area DA1 in front of the front frame 111 regardless of the posture of the working machine 120. Therefore, for example, even if the working machine 120 rises and a dead angle occurs in a predetermined area DA2 detected by the second external sensor 132, the first external sensor 131 can detect an avoidance target AO in front of the front frame 111.

[0077] Further, when the front frame 111 bends with respect to the rear frame 112 during turning of the work vehicle 100, an inclination angle occurs between the front-rear direction of the front frame 111 and the front-rear direction of the rear frame 112, and a dead angle may occur in a predetermined area DA2 detected by the second external sensor 132 attached to the rear frame 112. However, since the first external sensor 131 is attached to the front frame 111, even if the front frame 111 bends with respect to the rear frame 112, no dead angle occurs in a predetermined area DA1 through which the pair of front wheels 118 pass during straight travel of the work vehicle 100.

[0078] Also, the second external sensor 132 is attached at a position above the first external sensor 131 of the rear frame 112, and the detection direction can be changed from a predetermined area DA2 near the work vehicle 100 to a predetermined area DA2 far from the work vehicle 100 by the detection direction adjusting device 133. Therefore, the detection direction of the second external sensor 132 can be directed to the position of the avoidance target AO detected by the first external sensor 131, and the size of the avoidance target AO can be reliably detected.

[0079] As described above, the work vehicle 100 can more reliably detect the avoidance target AO on the travel path by the first external sensor 131 disposed on both sides of the working machine 120 of the front frame 111 and the second external sensor 132 attached at a position above the first external sensor 131 of the rear frame 112. As a result, the control device 140 can control the drive device 114 and the steering device 115 to avoid the avoidance target AO according to the size of the avoidance target AO detected by the second external sensor 132.

[0080] Therefore, according to the work vehicle 100 of the present embodiment, it is possible to prevent a decrease in the stability of the work vehicle 100 caused by the work vehicle 100 performing a predetermined operation in the automatic control mode, the semi-automatic control mode, or the manual control mode passing over the avoidance target AO at the work site. In other words, according to the work vehicle 100 of the present embodiment, context awareness with respect to an object around the work vehicle 100 can be realized, and the avoidance target AO that affects the stability of the work vehicle 100 can be dynamically detected.

[0081] Further, in the work vehicle 100 of the present embodiment, the control device 140 includes an avoidance target extraction unit 141, an avoidance area calculation unit 142, and a detection direction calculation unit 143. The avoidance target extraction unit 141 extracts the avoidance target AO based on information acquired from at least one of the first external sensor 131 and the second external sensor 132. The avoidance area calculation unit 142 calculates an avoidance area where the avoidance target AO exists based on the position of the extracted avoidance target AO. The detection direction calculation unit 143 calculates the angles θ1, θ2, θ3 of the detection direction of the second external sensor 132 based on the avoidance area.

[0082] With such a configuration, the work vehicle 100 of the present embodiment can identify an avoidance area including the avoidance target AO detected by the first external sensor 131, direct the detection direction of the second external sensor 132 toward the avoidance area, and detect the size of the avoidance target AO by the second external sensor 132. Therefore, according to the work vehicle 100 of the present embodiment, it becomes possible to more reliably detect the avoidance target AO on the travel path.

[0083] Further, the work vehicle 100 of the present embodiment further includes a braking device 116 that brakes at least one of a pair of front wheels 118 and a pair of rear wheels 119. The control device 140 includes a stability calculation unit 146 and an operation determination unit 148. The stability calculation unit 146 calculates the stability of the work vehicle 100 based on the size of the avoidance target AO. The operation determination unit 148 determines an avoidance operation to avoid the avoidance area by controlling at least one of the drive device 114, the steering device 115, or the braking device 116 when the stability calculated by the stability calculation unit 146 is lower than a predetermined threshold value.

[0084] With such a configuration, when the avoidance target AO affects the stability of the work vehicle 100, the work vehicle 100 of the present embodiment can execute an avoidance operation to avoid the avoidance area including the avoidance target AO under the control of the control device 140. Therefore, according to the work vehicle 100 of the present embodiment, it is possible to prevent a decrease in stability due to the avoidance target AO on the traveling path detected by the first external sensor 131 and the second external sensor 132.

[0085] As described above, the embodiments of the work vehicle according to the present disclosure have been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and even if there are design changes or the like within the scope not departing from the gist of the present disclosure, they are included in the present disclosure. For example, a part of the configuration of the control device 140 including the avoidance target extraction unit 141, the avoidance area calculation unit 142, and the detection direction calculation unit 143 may be provided in the first external sensor 131 or the second external sensor 132.

Description of Reference Numerals

[0086] 100 Work vehicle 111 Front frame 112 Rear frame 113 Connecting pin 114 Drive device 115 Steering device 116 Braking device 118 Front wheel 119 Rear wheel 120 Working machine 131 First external sensor 132 Second external sensor 133 Detection direction adjustment device 140 Control device 141 Avoidance target extraction unit 142 Avoidance area calculation unit 143 Detection direction calculation unit 146 Stability calculation unit 148 Operation determination unit AO Avoidance target DA1 Predetermined area

Claims

1. a front frame having a pair of front wheels; a rear frame having a pair of rear wheels; a connecting pin that connects the front frame to the rear frame in a bendable manner; a drive device that drives at least the pair of rear wheels; a steering device that bends the front frame with respect to the rear frame about the connecting pin; a working machine attached to the front frame; a first external sensor provided on the front frame so as to be positioned on both sides of the working machine, and detecting a position of an avoidance target when the avoidance target exists in a predetermined area through which the pair of front wheels in front of the front frame are about to pass; a second external sensor attached on the rear frame side at a position higher than the first external sensor, and detecting at least a size of the avoidance target detected by the first external sensor; a detection direction adjustment device that adjusts a detection direction of the second external sensor in the direction of the avoidance target based on the position of the avoidance target detected by the first external sensor; a control device that controls an operation of at least one of the drive device or the steering device based on the size of the avoidance target detected by the second external sensor based on the detection direction adjusted by the detection direction adjustment device; A work vehicle, characterized by comprising the above.

2. The control device includes an avoidance target extraction unit that extracts the avoidance target based on information acquired from at least one of the first external sensor and the second external sensor, an avoidance area calculation unit that calculates an avoidance area where the avoidance target exists based on the position of the extracted avoidance target, and a detection direction calculation unit that calculates an angle of the detection direction of the second external sensor based on the avoidance area. The work vehicle according to claim 1, characterized by comprising the above.

3. The work vehicle further includes a braking device that brakes at least one of the pair of front wheels and the pair of rear wheels. The control device includes a stability calculation unit that calculates a stability indicating the running stability of the work vehicle when the work vehicle passes over the avoidance target based on the size of the avoidance target, and an operation determination unit that determines an avoidance operation to avoid the avoidance area by controlling at least one of the drive device, the steering device, or the braking device when the stability is lower than a predetermined threshold value. The work vehicle according to claim 2, characterized by comprising the above. ​

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