JP2023147640A - work vehicle - Google Patents

Abstract

An object of the present invention is to provide a work vehicle that achieves steering by bending the vehicle body and can suppress contact with obstacles. [Solution] A front vehicle body, a rear vehicle body connected to the front vehicle body so as to be rotatable in the left and right directions, and a working machine provided in front of the front vehicle body, and the front vehicle body and the rear vehicle body are bendable. A work vehicle installed in , the maximum vehicle body occupation area, which is the area occupied by the working vehicle body, is calculated based on the change in the bending angle of the front vehicle body and the rear vehicle body, and if it is determined that there is an obstacle in the maximum vehicle body occupation region, the obstacle detection device detects the obstacle. Based on the results, the distance between the work vehicle and the obstacle is calculated, and based on the calculated distance, the limit value of the bending angle to prevent the work vehicle from coming into contact with the obstacle is calculated, and the bending angle of the front and rear bodies is calculated. Control so that the limit value is not exceeded. [Selection diagram] Figure 2

Description

The present invention relates to a work vehicle such as a wheel loader whose body is bent and steered.

For example, a working machine has a lift arm and a bucket tiltably attached to the tip of the lift arm, and the bucket is used for excavation to scoop up earth and sand, movement of the scooped earth and sand, and transportation of the scooped earth and sand, etc. Work vehicles, such as wheel loaders, are known for loading vehicles. In addition to the work equipment, the wheel loader includes a running device for driving the vehicle and a steering device for steering the vehicle by bending the vehicle body. Since the bucket attached to the wheel loader has a long width, it is necessary to control the movement of the working machine, which has a wide range of movement, so as not to come into contact with surrounding obstacles. Particularly, obstacle avoidance is an important function required for work vehicles equipped with autonomous driving functions.

As a conventional technique related to such obstacle avoidance, for example, the one described in Patent Document 1 is known. Patent Document 1 discloses a technique for ensuring a distance between the vehicle body and the obstacle by narrowly restricting the driving range near the obstacle in terms of the lateral position of the vehicle, thereby avoiding contact with the obstacle.

International Publication No. 2017/163790

However, in the above-mentioned prior art, the distance between the representative position of the vehicle body and the obstacle is only ensured, and a vehicle such as a wheel loader in which the occupied width of the vehicle body in the width direction changes is not considered. Specifically, in a bendable work vehicle that achieves steering by bending the vehicle body using a bending mechanism between the front and rear wheels of the vehicle, the amount of protrusion of the vehicle body in the width direction changes due to bending. There is a possibility that contact with obstacles cannot be avoided only by regulating the position of the vehicle body in the width direction. In particular, in a work vehicle equipped with a work equipment that has a bucket with a long width dimension, the amount of overhang from the bending point to the work equipment becomes large, so the amount of lateral overhang of the vehicle body due to bending becomes larger. This makes it even more difficult to avoid contact with obstacles.

The present invention has been made in view of the above, and an object of the present invention is to provide a work vehicle that achieves steering by bending the vehicle body and can suppress contact with obstacles.

The present application includes a plurality of means for solving the above problems, and one example thereof is a front vehicle body having a pair of left and right wheels; A working vehicle including a rear vehicle body having wheels of An obstacle detection device that detects the position and shape of an obstacle; and a control device that controls the bending angle of the front vehicle body and the rear vehicle body; A maximum vehicle body occupation area, which is an area occupied by the work vehicle, is calculated based on the change, and if it is determined that the obstacle exists in the maximum vehicle body occupation area, based on the detection result detected by the obstacle detection device. A distance between the work vehicle and the obstacle is calculated, a limit value of the bending angle at which the work vehicle does not come into contact with the obstacle is calculated based on the calculated distance, and a limit value of the bending angle at which the work vehicle does not contact the obstacle is calculated. The bending angle shall be controlled so as not to exceed the limit value.

According to the present invention, contact with obstacles can be suppressed in a work vehicle that achieves steering by bending the vehicle body.

FIG. 1 is a side view schematically showing the appearance of a wheel loader that is an example of a work vehicle. FIG. 1 is a diagram schematically showing the overall configuration of a control device that controls the bending angle of a wheel loader, together with related configurations. It is a figure which shows the example of the maximum vehicle body occupation area. It is a flowchart of the process concerning control of the bending angle of a vehicle body. FIG. 2 is a diagram schematically showing how earth and sand are put into a hopper as an example of work performed by a work vehicle. It is a figure which shows schematically the whole structure of the control apparatus which controls the bending angle of the wheel loader based on 2nd Embodiment, together with related structure. FIG. 2 is a diagram schematically showing how the own vehicle and other vehicles are operating at a work site. It is a figure showing the difference in the amount of overhang due to the difference in the angle of the working machine in the wheel loader. FIG. 3 is a diagram showing differences in maximum vehicle body occupation area due to differences in overhang amount.

Embodiments of the present invention will be described below with reference to the drawings. In this embodiment, an articulated wheel loader will be described as an example of a work vehicle, but the present invention can also be applied to other work vehicles such as an articulated dump truck. It is.

<First embodiment>
A first embodiment of the present invention will be described with reference to FIGS. 1 to 5.

FIG. 1 is a side view schematically showing the appearance of a wheel loader, which is an example of a work vehicle according to the present embodiment.

As shown in FIG. 1, the wheel loader 1 has a front body 11 (front vehicle body) having a pair of left and right front wheels 4a (wheels), and is connected to the front body 11 so as to be bendable (rotatable) in the left and right direction. , an articulated work vehicle equipped with a rear body 12 (rear vehicle body) having a pair of left and right rear wheels 4b (wheels), and a work machine consisting of a lift arm 2 and a bucket 3 provided in front of the front body 11. be. The rear body 12 includes a driver's cab 5, an engine compartment in which an engine 6 is placed, and the like. Note that hereinafter, the members constituting the wheel loader 1, such as the front body 11, the rear body 12, the bucket 3, the front wheels 4a, and the rear wheels 4b, may be collectively referred to as a "vehicle body."

The wheel loader 1 includes a pair of left and right lift arms 2 attached to the front end of a front body 11 by a pair of left and right lift cylinders 7 so as to be swingable in the vertical direction, and connected to the tip of the lift arms 2 so as to be rotatable in the vertical direction. The working machine includes a bucket 3 which is rotatably driven in the vertical direction by a bucket cylinder 8. The bucket 3 is rotated in the vertical direction by expansion and contraction of a bucket cylinder 8 connected via a bell crank 9 and a bucket link 10, so that the opening direction of the bucket 3 is moved up and down.

When pressure oil is supplied to the bottom chamber, the lift cylinder 7 extends and rotates the lift arm 2 upward (lifting up), and when pressure oil is supplied to the rod chamber, it retracts and moves the lift arm 2. Rotate downward (lower lift). When pressure oil is supplied to the bottom chamber, the bucket cylinder 8 expands and rotates (tilts) the bucket 3 upward, and when pressure oil is supplied to the rod chamber, it retracts and moves the bucket 3 downward. Rotate (dump).

The front body 11 and the rear body 12 are connected by a center pin 13 so as to be rotatable (bendable) in the left-right direction. The front body 11 is provided with a pair of left and right front wheels 4a, and the rear body 12 is provided with a pair of left and right rear wheels 4b. A pair of left and right steering cylinders 14 are provided between the front body 11 and the rear body 12 at the connecting portion between the front body 11 and the rear body 12 (on the left and right sides of the center pin 13). The wheel loader 1 can be steered by relatively rotating the rear body 12 in the left and right directions. For example, when the right steering cylinder 14 retracts and the left steering cylinder 14 extends, the wheel loader 1 bends to the right. Furthermore, when the right steering cylinder 14 extends and the left steering cylinder 14 retracts, the wheel loader 1 bends to the left. The rotation angle around the center pin 13 when the wheel loader 1 is bent is referred to as a bending angle, with the unbent state being zero and the bending to the right being taken as a plus.

The wheel loader 1 travels by rotating front wheels 4a and rear wheels 4b (hereinafter sometimes referred to collectively as wheels 4a and 4b). In a wheel loader 1 equipped with a general torque converter type traveling drive system, front and rear wheels 4a and rear wheels 4b are rotatable via an engine 6 and a drive train (not shown), such as a torque converter, a transmission propeller shaft differential, etc. It is connected. The wheel loader 1 can be driven forward and backward by transmitting the torque generated by the engine 6 to the wheels 4a, 4b via a power train composed of a torque converter and the like. Furthermore, the bending motion of the wheel loader 1 realizes steering while the vehicle is running.

An obstacle detection device 15 that detects the position and shape of obstacles around the wheel loader 1 is installed in a position of the wheel loader 1 where the surroundings can be seen, such as the upper part of the driver's cab 5, for example. The obstacle detection device 15 includes, for example, LiDAR, which measures the distance based on the time it takes for the laser beam irradiated on the surrounding area to return, and the direction from the irradiation angle, as well as LiDAR, which measures the direction from the irradiation angle, as well as a method for measuring obstacles. A camera or the like that calculates distance and direction from analysis is used. However, the measurement method is not limited to these, and other measurement methods may be used as long as the position and shape of the obstacle can be measured from the data group of the distance and direction of the surrounding obstacles. Since the mounting position of the obstacle detection device 15 with respect to the vehicle body is known from design information or the like, it is possible to detect the relative position of the obstacle with respect to the vehicle body.

A vehicle body position measuring device 16 is provided on the upper part of the rear body 12 behind the driver's cab 5 to detect the position of the wheel loader 1 at the work site. The vehicle body position measuring device 16 measures coordinates in a field coordinate system (or earth coordinate system), and is, for example, a GNSS (Global Navigation Satellite System). Since the mounting position of the vehicle body position measuring device 16 on the vehicle body, that is, the measurement position is known from design information or the like, it is possible to calculate the position of each part of the vehicle body in the field coordinate system.

FIG. 2 is a diagram schematically showing the overall configuration of a control device that controls the bending angle of a wheel loader, together with related configurations.

As shown in FIG. 2, the wheel loader 1 includes an autonomous driving system 300 that realizes an autonomous driving function. The control device 200 calculates the bending angle (steering angle) of the wheel loader 1 in consideration of the positional relationship between the vehicle body and obstacles based on the information from the autonomous driving system 300, and uses the calculated steering angle to the autonomous driving system 300. By returning the vehicle to the ground, contact with obstacles can be more reliably prevented. The control device 200 includes a trajectory following section 201, an obstacle position calculation section 202, an obstacle interference determination section 203, a clearance calculation section 204, a limit bending angle calculation section 205, and a target bending angle setting section 206.

The trajectory following unit 201 calculates the bending angle of the vehicle body for the wheel loader 1 to follow the trajectory (travel along the trajectory) based on the trajectory of the wheel loader 1 presented from the autonomous driving system 300. do. The travel trajectory presented by the autonomous driving system 300 is a route along which the wheel loader 1 should travel in a series of operations at the work site, and is predetermined in the form of continuous coordinate information on site map information or the like. The trajectory following unit 201 calculates a steering amount based on a forward gaze model, for example. This determines the forward gaze point, which is set on the traveling trajectory and in front of the wheel loader 1, as the passing point where the wheel loader 1 should travel. This is a steering model that determines the amount of steering based on the azimuth difference between the two. Note that many steering models for tracking the trajectory have been proposed, and the steering model is not limited to the forward gaze model. The trajectory following unit 201 calculates the bending angle of the vehicle body from the steering amount calculated using a steering model or the like, and outputs the calculated bending angle to the target bending angle setting unit 206 as a target bending angle.

The obstacle position calculation unit 202 calculates the relative position and shape of the obstacle with respect to the vehicle body based on the detection result from the obstacle detection device 15. Since the mounting position of the obstacle detection device 15 with respect to the vehicle body is known from design information or the like, it is possible to calculate the relative position of the obstacle with respect to the vehicle body from the detection result of the obstacle detection device 15. The obstacle position calculation unit 202 outputs the calculated position and shape of the obstacle to the obstacle interference determination unit 203 and the clearance calculation unit 204.

Obstacle interference determination section 203 determines whether there is a possibility of interference between an obstacle and the vehicle body, based on the calculation result from obstacle position calculation section 202 .

FIG. 3 is a diagram showing an example of the maximum vehicle body occupation area.

For example, as shown in FIG. 3, the obstacle interference determination unit 203 determines when the bending angle of the vehicle body of the wheel loader 1 has changed to the maximum, that is, when the bending angle is 0 (zero) (see reference line 301). The area through which the vehicle body passes when changing from the vehicle body state 302 at maximum left bending to the vehicle body state 303 at maximum right bending with center pin 13 as the center is calculated as the maximum vehicle body occupation area 304. That is, the maximum vehicle body occupation area 304 is an area occupied by the vehicle body of the wheel loader 1 due to a change in the bending angle, that is, an area occupied by the vehicle body on a plane when the vehicle body is viewed from above. Then, by determining whether or not the maximum vehicle body occupation area 304 overlaps with the obstacle occupation area determined from the position and shape of the obstacle calculated by the obstacle position calculation unit 202, the vehicle body and the obstacle are Determine whether there is a possibility of interference. Obstacle interference determination section 203 outputs the determination result to target bending angle setting section 206 .

The clearance calculation unit 204 calculates the distance (clearance information) between the vehicle body and the obstacle in the current state of the vehicle body (bending angle) based on the calculation result from the obstacle position calculation unit 202. The clearance calculation unit 204 calculates the nearest distance between the vehicle body contour and the obstacle in the current bent state of the vehicle body as clearance information. In the clearance information, the direction in which the obstacle exists as seen from the vehicle body is also expressed by a code or the like. For example, if right bending is defined as positive, the distance to the obstacle on the right side of the vehicle body is expressed as positive, and the distance to the obstacle on the left side of the vehicle body is expressed as negative. The clearance calculation section 204 outputs the calculation result to the limit bending angle calculation section 205.

Based on the calculation result from the clearance calculation unit 204, that is, the distance between the vehicle body and the obstacle, the limit bending angle calculation unit 205 calculates the maximum bending angle of the vehicle body without contacting an obstacle, that is, the bending of the vehicle body. Determine the corner limit value (limit bending angle). The limit bending angle calculation unit 205 outputs the calculation result to the target bending angle setting unit 206.

If the determination result of the obstacle interference determination unit 203 is that the vehicle body does not interfere with surrounding obstacles at any bending angle (there is no possibility of interference), the target bending angle setting unit 206 determines that the vehicle body does not interfere with surrounding obstacles at any bending angle. , the target bending angle input from the trajectory following unit 201 is adopted as is, and output to the autonomous driving system 300 as a set value of the target bending angle. On the other hand, if the judgment result of the obstacle interference judgment unit 203 is that there is a possibility that the vehicle body and the obstacle will interfere, the judgment result is based on the limit bending angle calculated by the limit bending angle calculation unit 205. Then, limit the target bending angle. That is, the target bending angle setting unit 206 adopts the angle with the same sign and smaller absolute value between the target bending angle and the limit bending angle input from the trajectory following unit 201 as the set value of the target bending angle, and performs autonomous driving. Output to system 300.

The autonomous driving system 300 controls the steering cylinder 14 to control the bending angle of the vehicle body based on the target bending angle set by the target bending angle setting unit 206, so that the wheel loader 1 follows the travel trajectory. This suppresses contact with obstacles due to bending while realizing the desired steering.

FIG. 4 is a flowchart of processing related to control of the bending angle of the vehicle body.

As shown in FIG. 4, the trajectory following section 201 first calculates a steering bending angle for following the trajectory (step S400).

Next, the obstacle detection device 15 measures the position and shape of the obstacle, and the obstacle position calculation unit 202 calculates the position and shape of the obstacle relative to the vehicle body (step S410).
Next, the obstacle interference determination unit 203 determines whether there is a possibility of interference between the obstacle and the vehicle body based on the position and shape of the obstacle calculated by the obstacle position calculation unit 202 (step S420), and determines It is determined whether the result indicates that there is interference between the obstacle and the vehicle body (step S430).

If the determination result in step S430 is NO, that is, if it is determined that there is no possibility of interference between the vehicle body and the obstacle, the target bending angle setting unit 206 sets the target bending angle setting value to the autonomous driving system 300. The steering angle (that is, the target bending angle) inputted from the controller is returned to the autonomous driving system 300 (step S461), and the autonomous driving system 300 adjusts the steering cylinder 14 based on the set value of the target bending angle from the target bending angle setting unit 206. Control is performed (step S480), and the process ends.

Further, if the determination result in step S430 is YES, that is, if it is determined that there is a possibility of interference between the vehicle body and the obstacle, the clearance calculation unit 204 calculates the distance between the vehicle body and the obstacle (step S440). ), the limit bending angle calculation unit 205 determines a limit value (limit bending angle) of the vehicle body bending angle at which the vehicle body does not come into contact with the obstacle, based on the calculated distance between the vehicle body and the obstacle (step S450).

Next, it is determined whether the steering angle (target bending angle) input from the autonomous driving system 300 is larger than the limit bending angle (step S460), and if the judgment result is NO, that is, the vehicle body is If there is no contact, the target bending angle setting unit 206 returns the steering angle (that is, the target bending angle) input from the autonomous driving system 300 as the set value of the target bending angle to the autonomous driving system 300 (step S461), and The driving system 300 controls the steering cylinder 14 based on the set value of the target bending angle from the target bending angle setting unit 206 (step S480), and ends the process.

Further, if the determination result in step S460 is YES, that is, if there is a possibility that the vehicle body will come into contact with an obstacle, the target bending angle setting unit 206 sets the limit bending angle as the upper limit. The angle is returned to the autonomous driving system 300 as the set value of the target bending angle (step S461), and the autonomous driving system 300 controls the steering cylinder 14 based on the set value of the target bending angle from the target bending angle setting unit 206 ( Step S480), the process ends.

The effect of this embodiment configured as above, that is, the effect of suppressing contact between the vehicle body and an obstacle will be explained.

FIG. 5 is a diagram schematically showing how earth and sand are put into a hopper as an example of work performed by a work vehicle.

As shown in Fig. 5, the most important work of the wheel loader 1, which is a working vehicle, is to move earth and sand. The work is representative. Further, in the work of putting earth and sand as materials into a plant or the like, work of putting earth and sand into a hopper 503 installed in a building is often seen. In this case, although there is no possibility that the position of the object to be loaded changes each time it is loaded, as is the case with a dump truck, it is necessary to accurately dump earth and sand into an area that is smaller than the bed of a dump truck. In addition, since the hopper 503 is often installed inside a building and often has a roof to protect it from rain, there are columns 502a, 502b, 502c, 502d, etc. around the hopper that support the rain protection. Sometimes I do. In this case, it is often not possible to provide a sufficient margin between the width of the bucket 3 of the working machine and the distance between the columns 502a and 502b. During such an approach run to the hopper 503, the distance 504 between the bucket 3 and the building is very narrow, and there is a high possibility that the vehicle body will come into contact with the building due to the lateral overhang caused by steering. In this embodiment, in such a work environment, the bending angle of the vehicle body is limited based on the distance 504 between the bucket 3 and the building (for example, the pillar 502a) to prevent contact between the vehicle body and obstacles. Therefore, it becomes possible to effectively suppress contact between the wheel loader 1 and the pillar 502a of the building.

<Second embodiment>
A second embodiment of the present invention will be described with reference to FIG.

In the first embodiment, the target bending angle of the vehicle body is calculated based on the travel trajectory presented by the autonomous driving system 300, whereas in the present embodiment, the target bending angle of the vehicle body is The future traveling trajectory is predicted from the current bending angle made by the steering command, and the vehicle body and obstacles interfere with each other within the vehicle body movable range around the predicted future traveling trajectory, that is, the trajectory that the vehicle body will move during driving. By determining whether or not there is interference, it is determined whether or not there will be interference with obstacles not only around the current vehicle but also around the vehicle position in the future. Furthermore, in this embodiment, since the steering command for determining the bending angle of the vehicle body is given from the outside, it can be applied not only to autonomous driving but also to manually steered driving by an operator.

In this embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted.

FIG. 6 is a diagram schematically showing the overall configuration of a control device for controlling the bending angle of the wheel loader according to the present embodiment, together with related configurations.

As shown in FIG. 6, the wheel loader 1 has a travel system 300A that implements driving functions. The control device 200A calculates the bending angle (steering angle) of the wheel loader 1 in consideration of the positional relationship between the vehicle body and obstacles based on information from the handle 507 installed in the driver's cab 5, and calculates the calculated steering angle. By outputting this to the traveling system 300A, contact with obstacles can be more reliably prevented. The control device 200A includes a travel trajectory prediction section 501, an obstacle position calculation section 202, an obstacle interference determination section 203a, a clearance calculation section 204a, a limit bending angle calculation section 205a, and a target bending angle setting section 206a.

The travel trajectory prediction unit 501 calculates a predicted value of the future travel trajectory of the wheel loader 1 based on the current vehicle body bending angle. Although not detailed here, the curvature of the travel trajectory is calculated approximately in proportion to the bending angle of the vehicle body due to the geometrical relationship when turning in a bending type work vehicle. It is possible to formulate predicted values for future travel trajectories. The travel trajectory prediction unit 501 outputs the calculated travel trajectory prediction value to the obstacle interference determination unit 203a and the clearance calculation unit 204a.

The obstacle position calculation unit 202 calculates the relative position and shape of the obstacle with respect to the vehicle body based on the detection result from the obstacle detection device 15. Since the mounting position of the obstacle detection device 15 with respect to the vehicle body is known from design information or the like, it is possible to calculate the relative position of the obstacle with respect to the vehicle body from the detection result of the obstacle detection device 15. The obstacle position calculation unit 202 outputs the calculated position and shape of the obstacle to the obstacle interference determination unit 203a and the clearance calculation unit 204a.

The obstacle interference determination unit 203a compares the calculation results from the obstacle position calculation unit 202 with the predicted travel trajectory from the travel trajectory prediction unit 501 to determine whether there is a possibility of interference between the obstacle and the vehicle body. do. Obstacle interference determining section 203a outputs the determination result to target bending angle setting section 206a.

The clearance calculation unit 204a compares the calculation result from the obstacle position calculation unit 202 with the predicted travel trajectory value from the travel trajectory prediction unit 501, and calculates the future distance between the vehicle body and the obstacle (clearance information). do. The clearance calculation section 204a outputs the calculation result to the limit bending angle calculation section 205a.

The limit bending angle calculating section 205a calculates the maximum bending angle of the vehicle body without contacting an obstacle, based on the calculation result from the clearance calculating section 204a, that is, the future distance between the vehicle body and the obstacle. Determine the limit value of the bending angle (limit bending angle). The limit bending angle calculation unit 205a outputs the calculation result to the target bending angle setting unit 206a.

The target bending angle setting unit 206a determines that the judgment result of the obstacle interference judgment unit 203a is that the surrounding obstacles and the vehicle body do not interfere with each other in the predicted travel trajectory of the wheel loader 1 (there is no possibility of interference). If so, the target bending angle input from the handle 507 is adopted as is, and is output to the traveling system 300A as the set value of the target bending angle. On the other hand, if the determination result of the obstacle interference determination unit 203a is that there is a possibility that the vehicle body and the obstacle will interfere in the predicted travel trajectory of the wheel loader 1, the limit bending angle calculation unit The target bending angle is limited based on the limit bending angle calculated in step 205a. That is, the target bending angle setting unit 206a adopts the angle with the same sign and smaller absolute value between the target bending angle and the limit bending angle input through the handle 507, and sets the target bending angle to the driving system 300A. Output.

The traveling system 300A controls the steering cylinder 14 to control the bending angle of the vehicle body based on the target bending angle set by the target bending angle setting unit 206a, so that the wheel loader 1 performs the steering desired by the operator. While achieving this, it also suppresses contact with obstacles due to bending.

Other configurations are similar to those of the first embodiment.

In this embodiment configured as described above, the same effects as in the first embodiment can be obtained.

Note that although this embodiment exemplifies a case where a work vehicle that performs manual steering travel avoids interference with obstacles, it is also possible to configure the system so that the input of the steering command is given from an autonomous traveling system (not shown). Therefore, the present invention can also be applied to autonomous driving systems.

<Modifications of the first and second embodiments>
Modifications of the first and second embodiments of the present invention will be described. In this modification, the same reference numerals are used for the same components as in the first and second embodiments, and the description thereof will be omitted.

In the first and second embodiments, a LiDAR is installed in a position where the surroundings can be seen, such as the upper part of the driver's cab 5, and measures the distance based on the time it takes for the laser beam irradiated onto the surrounding area to return and the direction from the irradiation angle. , the case where the obstacle detection device 15, such as a camera, which calculates the distance and direction mainly from the analysis of a plurality of images, is grounded has been explained as an example. On the other hand, in this modification, obstacle information described in a pre-created vehicle surrounding map is used.

For example, information on fixed obstacles such as buildings whose positions and shapes are clearly known can be recorded on a map in advance, and the positions and shapes of surrounding obstacles can be reconstructed by comparing it with the own vehicle's position. It is possible. In addition, it is created using obstacle measuring devices not installed on the own vehicle, specifically obstacle information collected by surrounding vehicles, or obstacle information collected using measuring devices fixed on the ground. It is also possible to supply and use maps via data communication or the like. In this case, it is conceivable that the ground base station is equipped with a processing device that aggregates the collected obstacle information and integrates it into a map.

The other configurations are the same as those in the first and second embodiments.

Even in this modified example configured as described above, the same effects as in the first and second embodiments can be obtained.

Note that by using the detection results from the obstacle detection device shown in the first and second embodiments together with the obstacle information previously written on the map shown in this modification, obstacles can be detected. It may be configured to detect this.

<Third embodiment>
A third embodiment of the present invention will be described with reference to FIG.

In the first and second embodiments, a LiDAR is installed in a position where the surroundings can be seen, such as the upper part of the driver's cab 5, and measures the distance based on the time it takes for the laser beam irradiated onto the surrounding area to return and the direction from the irradiation angle. , the case where the obstacle detection device 15, such as a camera, which calculates the distance and direction mainly from the analysis of a plurality of images, is grounded has been explained as an example. Further, in the modified examples of the first and second embodiments, obstacle information is obtained based on a map created in advance. In contrast, in the present embodiment, obstacle information is acquired based on position and attitude information sent from other vehicles in the vicinity of the host vehicle via wireless communication means or the like.

In this embodiment, the same components as in the first and second embodiments are denoted by the same reference numerals, and explanations thereof will be omitted.

FIG. 7 is a diagram schematically showing how the own vehicle and other vehicles are operating at a work site.

As shown in FIG. 7, at the work site, in addition to work vehicles such as the own vehicle, such as the wheel loader 1, other work vehicles such as dump trucks 1A and 1B are operating. That is, at a work site, there may be a situation in which other work vehicles that cooperate to perform work around the wheel loader 1, which is the own vehicle, become obstacles. For example, there is a case where dump trucks 1A, 1B, etc. that transport earth and sand excavated and moved by the wheel loader 1, which is the own vehicle, become an obstacle.

In a site where autonomous work is performed, other vehicles such as dump trucks 1A and 1B also need to run autonomously, so the self-position and posture information of each vehicle may be measured using vehicle body position measuring devices 16a and 16b. is required. Alternatively, it is conceivable to measure position and posture information from the viewpoint of vehicle management even in manned manual driving.

Therefore, in the wheel loader 1 according to the present embodiment, position and attitude information of other vehicles (dump trucks 1A, 1B, etc.) and dimension information of the vehicle that is known in advance are transmitted via communication devices 905, 905a, 905b. The contour information of other vehicles is calculated from the acquired information and used as information indicating the position and shape of the obstacle. Then, by comparing the obstacle information obtained from the information acquired from other vehicles with the contour information of the wheel loader 1 (see the maximum vehicle body occupation area 304 in FIG. 3), which is the own vehicle, the vehicle body (own vehicle) It is possible to determine the possibility of interference from obstacles (other vehicles).

The other configurations are the same as the first and second embodiments and their modifications.

Also in this embodiment configured as above, the same effects as in the first and second embodiments and their modifications can be obtained.

<Fourth embodiment>
A fourth embodiment of the present invention will be described with reference to FIGS. 8 and 9.

In this embodiment, the maximum vehicle body occupation area is calculated in consideration of changes in the amount of overhang at the front and rear of the vehicle body. In this embodiment, the same components as those in the first and second embodiments are denoted by the same reference numerals, and explanations thereof will be omitted.

FIG. 8 is a diagram showing the difference in overhang amount due to the difference in the angle of the working machine in the wheel loader.

As shown in FIG. 8, in the wheel loader 1, the amount of overhang at the front of the vehicle body changes depending on the angle of the working machine constituted by the lift arm 2 and the bucket 3. For example, when the position of the center pin 13 is used as a reference, the overhang amount 71 when the lift arm is lowered is larger than the overhang amount 72 when the lift arm is raised. Furthermore, when the overhang amount changes, the maximum vehicle body occupation area (for example, see maximum vehicle body occupation area 304 in FIG. 3) determined using the vehicle body size also changes.

FIG. 9 is a diagram showing the difference in the maximum vehicle body occupation area due to the difference in the overhang amount.

As shown in FIG. 9, at the position 802 of the bucket 3 when the lift arm is lowered, the distance from the center pin 13 is long, so that the maximum vehicle body occupation area 804 is obtained. Further, since the position 803 of the bucket 3 when the lift arm is raised is relatively close to the center pin 13, the maximum vehicle body occupation area 805 is obtained.

Therefore, for example, the overhang amount is calculated based on the detection result from the angle sensor 70 provided on the rotation axis of the lift arm 2 on the front body 11 side and the dimensional information of the vehicle body, and from this overhang amount, the maximum vehicle body Calculate the occupied area. This allows a more accurate maximum vehicle body occupation area to be calculated. Furthermore, by using the maximum vehicle body occupation area calculated in this way, the obstacle interference determination units 203 and 203a can make determinations with higher accuracy.

The other configurations are the same as those in the first and second embodiments.

In this embodiment configured as described above, the same effects as in the first embodiment can be obtained.

<Additional notes>
Note that the present invention is not limited to the above-described embodiments, and includes various modifications and combinations within the scope of the invention. Furthermore, the present invention is not limited to having all the configurations described in the above embodiments, but also includes configurations in which some of the configurations are deleted. Moreover, each of the above-mentioned configurations, functions, etc. may be realized in part or in whole by, for example, designing an integrated circuit. Furthermore, each of the above configurations, functions, etc. may be realized by software by a processor interpreting and executing a program for realizing each function.

1... Wheel loader, 1A, 1B... Dump truck, 2... Lift arm, 3... Bucket, 4a... Front wheel, 4b... Rear wheel, 5... Cab, 6... Engine, 7... Lift cylinder, 8... Bucket cylinder, 9 ...Bell crank, 10...Bucket link, 11...Front body, 12...Rear body, 13...Center pin, 14...Steering cylinder, 15...Obstacle detection device, 16, 16a, 16b...Vehicle body position measurement device, 70...Angle sensor , 71, 72...Overhang amount, 200, 200A...Control device, 201...Trajectory following section, 202...Obstacle position calculation section, 203,203a...Obstacle interference determination section, 204,204a...Clearance calculation section, 205, 205a...Limit bending angle calculation unit, 206, 206a...Target bending angle setting unit, 300...Autonomous driving system, 300A...Driving system, 304...Maximum vehicle body occupation area, 501...Driving trajectory prediction unit, 502a, 502b, 502c, 502d ...Column, 503...Hopper, 504...Spacing, 507...Handle, 804, 805...Maximum vehicle body occupation area, 905, 905a, 905b...Communication device

Claims (6)

A front vehicle body having a pair of left and right wheels, a rear vehicle body rotatably connected to the front vehicle body in the left and right direction and having a pair of left and right wheels, and a working machine provided in front of the front vehicle body. , a work vehicle in which the front vehicle body and the rear vehicle body are provided to be bendable,
an obstacle detection device that detects the position and shape of obstacles existing around the work vehicle;
a control device that controls bending angles of the front vehicle body and the rear vehicle body,
The control device includes:
calculating a maximum vehicle body occupation area that is an area occupied by the work vehicle based on a change in the bending angle of the front vehicle body and the rear vehicle body;
If it is determined that the obstacle exists in the maximum vehicle body occupation area,
The distance between the work vehicle and the obstacle is calculated based on the detection result detected by the obstacle detection device, and the bending angle at which the work vehicle does not come into contact with the obstacle is determined based on the calculated distance. A work vehicle characterized in that a limit value is calculated and the bending angle of the front vehicle body and the rear vehicle body is controlled so as not to exceed the limit value. The work vehicle according to claim 1,
The control device includes:
When controlling the bending angle of the front vehicle body and the rear vehicle body so that the work vehicle travels along a predetermined travel trajectory, the bending angle is controlled so as not to exceed the limit value. work vehicle. The work vehicle according to claim 1,
The control device includes:
Calculate the predicted future travel trajectory from the current bending angle,
calculating an expected distance between the work vehicle and the obstacle based on the detection result from the obstacle detection device and the predicted travel trajectory;
Based on the predicted distance, calculate a limit value of the bending angle at which the work vehicle will not come into contact with the obstacle by traveling on the predicted travel trajectory;
A work vehicle characterized in that the bending angle is controlled so as not to exceed the limit value. The work vehicle according to claim 2 or 3,
The work vehicle is characterized in that the control device acquires information on the positions and shapes of obstacles included in a surrounding map created in advance around the work vehicle. The work vehicle according to claim 2 or 3,
The control device is characterized in that the control device acquires information on the position and shape of the obstacle based on information on the position and orientation of the other work vehicle transmitted from another work vehicle existing in the vicinity of the work vehicle. work vehicle. The work vehicle according to claim 2 or 3,
A work vehicle, wherein the control device calculates a distance between the work vehicle and the obstacle based on posture information of a work implement of the work vehicle.

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