JP6378958B2 - Mine dump truck - Google Patents

Description

  The present invention relates to a dump truck used in a mine.

  In the mine, ensuring safety and improving transport efficiency are the most important issues. In order to improve the conveyance efficiency, various types of vehicles such as vehicles for transporting earth and sand and vehicles for excavation are coming and going from the mining site almost every 24 hours a day.

  In order to prevent a collision accident, a dump truck used in a mine is equipped with a mechanical brake (emergency brake device) used during emergency braking in addition to an electric brake (ordinary brake device) used during normal braking. During emergency braking, the electric brake and the mechanical brake cooperate to stop the vehicle.

  This brake operation is performed by an operator who operates a mining dump truck. For this reason, a collision accident may occur due to an operator's operation mistake or the like. When a collision accident occurs, it is necessary to stop the operation of the mine, leading to a decrease in transport efficiency. Further, since the disc of the mechanical brake is easily worn, it is not preferable to use the mechanical brake frequently from the viewpoint of the life of the mechanical brake.

  Patent Document 1 is known as a technique for avoiding a collision. Patent Document 1 states that “a braking force or a braking reduction is automatically performed in a plurality of stages in a time series automatically when a TTC derived based on a relative distance and a relative speed between an object and the vehicle falls below a set value. A configuration is described in which stepwise braking control for gradually increasing the speed is performed (see abstract).

JP 2007-223582 A

  However, Patent Document 1 merely discloses a technique for notifying an operator with an alarm or stopping a vehicle in order to avoid a collision with an obstacle based on one type of braking force. That is, Patent Document 1 describes how a brake is controlled to collide with a mine dump truck having two different types of brake devices, a normal brake device used during normal braking and an emergency brake device used during emergency braking. There is no mention of how to avoid it.

  An object of the present invention is to realize brake control suitable for avoiding a collision with an obstacle in a mining dump truck having a normal brake device and an emergency brake device.

In order to achieve the above object, a mine dump truck according to the present invention includes a handle operated by an operator, an obstacle detection device for detecting an obstacle, a normal brake device used during normal braking, and an emergency braking device. An emergency brake device that performs the operation, the first notification unit that performs notification for prompting the operation of the normal brake device, the second notification unit that performs notification for prompting the operation of the emergency brake device, and the operation of the handle A third notification unit that performs notification for the purpose, a collision possibility determination unit that determines the possibility of a collision with the obstacle based on a detection result of the obstacle detection device, the normal brake device, and the emergency brake A brake control unit that controls the operation of the device, and the collision possibility determination unit operates a first danger that can avoid a collision with the obstacle by operating the normal brake device. Or the second risk level that requires the operation of the emergency brake device to avoid a collision with the obstacle, and the brake control unit determines the first risk level based on the determination of the first risk level. The normal brake device is operated, the emergency brake device is operated based on the determination with the second risk level, and the collision possibility determination unit determines whether the collision between the obstacle and the obstacle is detected from the detection result of the obstacle detection device. An obstacle information recognition unit that calculates a distance between two points and a relative speed with the obstacle, and calculates a collision prediction time by dividing the distance between the two points obtained by the obstacle information recognition unit by the relative speed. A collision prediction time calculation unit, a first threshold value set as a time limit for avoiding a collision with the obstacle by operating the normal brake device, and a collision with the obstacle by operating the emergency brake device. Can be avoided A second threshold value set as a limit time to be compared with the predicted collision time, and when the predicted collision time is substantially equal to the first threshold value, the first risk is determined, and the predicted collision time A risk level determination unit that determines that the second risk level is approximately equal to the second threshold value, and the risk level determination unit adds a predetermined margin to the first threshold value. When the first warning threshold value is substantially equal, the first notification command is output to the first notification unit, and the predicted collision time is substantially equal to the second warning threshold value obtained by adding a predetermined margin to the second threshold value. A second notification command is output to the second notification unit, and the collision prediction time is smaller than the first alarm threshold and greater than the second alarm threshold, and an operator operates the handle. Colliding with the obstacle When it is determined that it can be avoided, a third notification command is output to the third notification unit, the first notification unit notifies based on the first notification command, and the second notification unit responds to the second notification command. The third notification unit performs notification based on the third notification command, and the notification by the third notification unit is after the notification by the first notification unit and is notified by the second notification unit. It is performed before .

According to the present invention, the normal brake device and the emergency brake device can be appropriately used according to the degree of danger, and a collision with an obstacle can be avoided. Therefore, suitable brake control can be realized. Moreover, since this invention can prevent operating an emergency brake unnecessarily, it can suppress wear of an emergency brake device and can aim at lifetime improvement. Further, the collision prediction time is obtained by calculating the distance between the two points with the obstacle and the relative speed with the obstacle, and when the collision prediction time and the first threshold value are substantially equal, it is determined as the first risk level. Since the brake device can be operated, a collision with an obstacle can be safely avoided. Further, according to the present invention, when the predicted collision time and the second threshold value are substantially equal, it is possible to operate the emergency brake device by determining the second risk level, so that it is possible to safely avoid a collision with an obstacle. it can. In addition, since the operator is informed in advance that the brake operation is urged before the normal brake device is activated and before the emergency brake device is activated, the brake braking of the vehicle can be entrusted to the operator's skill. Will be good. In addition, when the collision can be avoided by the steering operation, it is possible to prevent unnecessary emergency brake operation by notifying that effect, so that the wear of the emergency brake device can be further suppressed. In addition, since it is left to the operator to determine whether to operate the steering wheel or brake, it is convenient for the operator.

  The present invention further includes a load detector for detecting the presence or absence of a load in the above configuration, wherein the risk determination unit includes the first threshold value whose value is changed according to a detection value of the load detector, and The first risk level and the second risk level are determined based on the second threshold value.

  According to the present invention, since braking can be applied depending on whether the mine dump truck is in a loaded state or an empty state, safety is further improved.

  Further, according to the present invention, in the configuration described above, the first threshold value and the second threshold value when there is a load are changed to values larger than the first threshold value and the second threshold value when there is no load, respectively. The present invention is characterized in that the timing when the brake control unit operates the normal brake device and the emergency brake device is advanced as compared with the case where there is no load.

  According to the present invention, when the mining dump truck is in a loaded state, the risk of a collision can be further avoided and safety can be improved by advancing the operation timing of the brake.

  The present invention may further include an inclination detector that detects an inclination of a road surface in the above-described configuration, wherein the risk determination unit includes the first threshold value that is changed according to a detection value of the inclination detector, and The first risk level and the second risk level are determined based on the second threshold value.

  According to the present invention, brake braking can be applied in accordance with the slope of the road surface, so safety is further improved.

  Further, according to the present invention, in the configuration described above, the first threshold value and the second threshold value when the road surface is downwardly inclined are set to values larger than the first threshold value and the second threshold value when the road surface is upwardly inclined, respectively. By changing, the timing when the brake control unit operates the normal brake device and the emergency brake device is earlier in the case where the road surface is inclined downward than in the case where the road surface is inclined upward. It is characterized by that.

  According to the present invention, when the road surface is inclining downward, the risk of collision can be further avoided by increasing the brake operation timing, and safety is improved.

  Further, the present invention is the above configuration, wherein the collision possibility determination unit includes a road surface state estimation calculation unit that calculates a friction coefficient of a road surface, and the risk determination unit includes the friction calculated by the road surface state estimation calculation unit. The first risk level and the second risk level are determined based on the first threshold value and the second threshold value whose values are changed according to a coefficient.

  According to the present invention, since braking can be applied depending on whether the road surface is slippery or not, safety is further improved.

  In the above configuration, the present invention is configured such that the first threshold value and the second threshold value when the road surface has a low friction coefficient are larger than the first threshold value and the second threshold value when the road surface has a high friction coefficient, respectively. By changing the value, the timing when the brake control unit operates the normal brake device and the emergency brake device when the road surface has a low friction coefficient compared to when the road surface has a high friction coefficient. It is characterized by having been advanced.

  According to the present invention, when the road surface is slippery, the risk of a collision can be avoided more and the safety is improved by advancing the brake operation timing.

  Further, the present invention, in the above configuration, includes a normal brake pedal as the normal brake device and an emergency brake pedal as the emergency brake device, and the brake control unit is configured so that an operator's normal brake pedal and the emergency brake pedal are The operation of the brake pedal is received, and the operation of the normal brake device and the emergency brake device is controlled.

  According to the present invention, since the operator can perform the brake operation himself / herself, the usability is further improved. In addition, when a collision cannot be avoided by the brake operation by the operator, the brake control unit automatically operates the normal brake device or the emergency brake device, thereby ensuring safety.

  Further, according to the present invention, in the configuration described above, the obstacle information recognition unit recognizes a vehicle traveling in front as the obstacle, a distance between two points with the traveling vehicle, and the traveling The relative speed of the vehicle is calculated.

  According to the present invention, since it is possible to avoid a collision with a vehicle traveling in front of the vehicle, it is safer in a mine.

  ADVANTAGE OF THE INVENTION According to this invention, the brake control suitable for avoiding the collision with an obstruction can be implement | achieved with respect to the dump truck for mines provided with the normal brake device and the emergency brake device. Problems, configurations, and effects other than those described above will be clarified by the following description of the embodiments.

1 is a side view of a mining dump truck according to a first embodiment of the present invention. It is explanatory drawing which shows the inside of the cab of the mine dump truck shown in FIG. It is a whole block diagram of the mine dump truck shown in FIG. It is a block diagram which shows the detail of the collision possibility determination device which concerns on 1st Embodiment. It is a figure for demonstrating the determination method of the risk level in 1st Embodiment. It is a flowchart which shows the process sequence of the risk determination part which concerns on 1st Embodiment. It is a whole block diagram of the dump truck which concerns on 2nd Embodiment. It is a block diagram which shows the detail of the collision possibility determination device which concerns on 2nd Embodiment. It is a figure for demonstrating the determination method of the risk level in 2nd Embodiment. It is a flowchart which shows the process sequence of the risk determination part which concerns on 2nd Embodiment. It is a whole block diagram of the dump truck which concerns on 3rd Embodiment. It is a block diagram which shows the detail of the collision possibility determination device which concerns on 3rd Embodiment. It is a figure for demonstrating the determination method of the risk level in 3rd Embodiment. It is a flowchart which shows the process sequence of the risk determination part which concerns on 3rd Embodiment. It is a whole block diagram of the dump truck which concerns on 4th Embodiment. It is a block diagram which shows the detail of the collision possibility determination device which concerns on 4th Embodiment. It is a figure for demonstrating the determination method of the risk level in 4th Embodiment. It is a figure for demonstrating the determination method of the risk level in 4th Embodiment. It is a figure for demonstrating the determination method of the risk level in 4th Embodiment. It is a flowchart which shows the process sequence of the risk determination part which concerns on 4th Embodiment. It is a flowchart which shows the process sequence of the risk determination part which concerns on 4th Embodiment. It is a whole block diagram of the dump truck which concerns on 5th Embodiment. It is a block diagram which shows the detail of the collision possibility determination device which concerns on 5th Embodiment. It is a figure for demonstrating the determination method of the risk level in 5th Embodiment, Comprising: It is a figure which shows the relationship between the presence or absence of a load, and a risk level. It is a figure for demonstrating the determination method of the danger in 5th Embodiment, Comprising: It is a figure which shows the relationship between the inclination of a road surface, and a danger. It is a figure for demonstrating the determination method of the danger in 5th Embodiment, Comprising: It is a figure which shows the relationship between a road surface state and a danger. It is a figure for demonstrating the determination method of the risk level in 6th Embodiment, Comprising: It is a figure which shows the relationship between the moving direction of a moving body, and a risk level.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected about the same structure through all the figures, and duplication description is abbreviate | omitted.

<First Embodiment>
Based on FIGS. 1-3, the structure of the dump truck for mine which concerns on 1st Embodiment is demonstrated. FIG. 1 is a side view of a mining dump truck according to a first embodiment of the present invention. FIG. 2 is an explanatory diagram showing the inside of the cab of the mining dump truck shown in FIG. FIG. 3 is an overall configuration diagram of the mining dump truck shown in FIG. 1.

  As shown in FIG. 1, a mine dump truck (hereinafter abbreviated as “dump truck”) 100 according to this embodiment includes a body frame 60, a pair of front wheels 7, 8, a pair of rear wheels 3, 6, and a cargo bed. 61 is provided. The pair of front wheels 7 and 8 are rotatably attached to the left and right ends of the front portion of the body frame 60. The pair of rear wheels 3 and 6 are rotatably attached to both left and right ends of the rear portion of the body frame 60. Furthermore, the loading platform 61 is a portion on which a transport object such as earth and sand or crushed stone is loaded, and is attached to the vehicle body frame 60 so as to be raised and lowered.

  Further, above the front wheel 7 on the left side of the vehicle body frame 60, a cab 62, which is a cab in which an operator gets, is provided. Further, although not shown, a power unit that houses an engine, hydraulic equipment, and the like is provided at the front portion of the vehicle body frame 60.

  As shown in FIG. 2, a seat 90 on which an operator sits is provided in the cab 62, and a steering handle 91 is provided in front of the operator seated on the seat. A normal brake pedal 92 and an accelerator pedal 93 are arranged on the right side when viewed from the operator at the base of the steering handle 91. An emergency brake pedal 94 is provided on the left side of the steering handle 91 as viewed from the operator at the base.

  The normal brake pedal 92 is an element that is used during normal braking and constitutes the “normal brake device” of the present invention. In the normal braking operation using the normal brake pedal 92, the vehicle is decelerated mainly by the electric brake, and the vehicle is stopped in cooperation with the mechanical brakes 24, 25, 26, and 27 (see FIG. 3) immediately before stopping.

  That is, when the operator depresses the normal brake pedal 92, electric motors 1 and 4 (see FIG. 3) described later function as a generator, and the regenerated electricity is consumed by the power consuming device (retarder) 56 (see FIG. 3). To brake and decelerate. Then, the dump truck 100 is stopped by operating the mechanical brake at a speed immediately before the stop, for example, 0.5 km / h or less.

  The emergency brake pedal 94 is an element that is used during emergency braking and constitutes the “emergency brake device” of the present invention. In the emergency braking operation using the emergency brake pedal 94, the mechanical brakes 24, 25, 26, 27 (see FIG. 3) including the brake disc and the electric brake are simultaneously operated to decelerate and stop the vehicle.

  That is, when the operator depresses the emergency brake pedal 94, the electric brake and the mechanical brake are fully operated simultaneously. As a result, the vehicle speed can be reduced by a braking force larger than that of the normal brake, and the vehicle body can be stopped in a shorter time.

  The braking force of the normal brake device that is activated by depressing the normal brake pedal 92 and the braking force of the emergency brake device that is activated by depressing the emergency brake pedal 94 are controlled by the emergency brake device when operated in the same environment. The power is usually larger than the braking force of the brake device.

  In the present embodiment, the normal brake pedal 92 and the emergency brake pedal 94 are configured separately. However, these are configured by one brake pedal, and if the depression amount is less than the threshold value, the normal brake is set to the threshold value or more. If there is, the emergency brake may be operated.

  In front of the steering handle 91, a front panel 95 including instruments and a camera monitor that displays an image of the periphery of the dump truck 100 is provided.

  Next, the overall configuration of the dump truck 100 will be described. As shown in FIG. 3, the dump truck 100 moves forward or backward when the electric motor 1 drives the rear wheel 3 via the gear 2 and the electric motor 4 drives the rear wheel 6 via the gear 5. That is, in this embodiment, the rear wheels 3 and 6 are drive wheels, and the front wheels 7 and 8 are driven wheels.

  Moreover, although illustration is abbreviate | omitted, the dump truck 100 carries the engine as a motive power source, and the generator which converts the motive power of an engine into an electrical energy. The generated power is supplied to the power converter 13. The electric motor 1 and the electric motor 4 are controlled by an electric motor controller 29, and the power converter 13 drives the electric motor 1 and the electric motor 4. The current detector 14 is connected between the power converter 13 and the electric motor 1 and detects a current flowing between them. The current detector 15 is connected between the power converter 13 and the electric motor 4 and detects a current flowing between them. The current values detected by the current detectors 14 and 15 are output to the torque controller 16.

  The speed detector 9 is connected to the electric motor 1 and detects the rotational speed of the electric motor 1. The speed detector 10 is connected to the electric motor 4 and detects the rotational speed of the electric motor 4. The speed detector 11 is connected to the shaft of the front wheel 7 and detects the rotational speed of the front wheel 7. The speed detector 12 is connected to the shaft of the front wheel 8 and detects the rotational speed of the front wheel 8. The rotational speed values detected by the speed detectors 9, 10, 11, and 12 are output to the collision possibility determination unit 30. The rotational speed value detected by the speed detectors 9 and 10 is also output to the torque controller 16.

  The accelerator opening detector 19 detects the opening of the accelerator pedal 93 according to the operator's accelerator operation, and the brake opening detector 20 detects the opening of the normal brake pedal 92 according to the operator's normal brake operation. The steering angle detector 21 detects the angle of the steering handle 91 according to the steering operation of the operator. Each detected value is output to the torque command calculator 17.

  The emergency brake operation detector 22 detects the operation of the emergency brake pedal and outputs an emergency brake operation detection value to the emergency brake controller 23. The emergency brake controller 23 uses the input of the emergency brake operation detection value output from the emergency brake operation detector 22 as a trigger, and outputs the input emergency brake operation detection value to the torque command calculator 17 and each mechanical brake 24. , 25, 26 and 27, the operation command is output. The detection value of the emergency brake operation detector 22 is also output to the collision possibility determination unit 30 via the emergency brake controller 23.

  The torque command calculator 17 outputs an accelerator opening detection value output from the accelerator opening detector 19, a brake opening detection value output from the brake opening detector 20, and a steering angle detection value output from the steering angle detector 21. As inputs, a torque command to the motor 1 and a torque command to the motor 4 are calculated, and these torque commands are output to the torque controller 16.

  Here, when the emergency brake operation detector 22 outputs the emergency brake operation detection value, the torque command calculator 17 outputs the accelerator opening detection value output from the accelerator opening detector 19 and the brake opening detector 20. Regardless of the brake opening detection value to be output, the same torque reduction command as when the normal brake pedal 92 is fully depressed is output to the torque controller 16.

  The torque controller 16 outputs the output of the motor 1 from the torque command output to the motor 1 output from the torque command calculator 17, the current detection value output from the current detector 14, and the rotation speed detection value output from the speed detector 9. A gate pulse signal is output to the power converter 13 by PWM (Pulse Width Modulation) control so that the torque to be performed follows the torque command to the electric motor 1.

  Similarly, the torque controller 16 calculates the torque command to the motor 4 output from the torque command calculator 17, the current detection value output from the current detector 15, and the rotation speed detection value output from the speed detector 10. A gate pulse signal is output to the power converter 13 by PWM control so that the torque output from the motor 4 follows the torque command to the motor 4.

  The power converter 13 receives these gate pulse signals, and a switching element such as an IGBT (Insulated Gate Bipolar Transistor) performs switching at high speed, thereby realizing highly responsive torque control.

  The power consuming device 56 has a function of consuming electric power regenerated by the electric motor 1 and the electric motor 4 when the vehicle decelerates.

  A collision possibility determination unit (collision possibility determination unit) 30 receives an input from an obstacle detection sensor (obstacle detection device) 28 such as a millimeter wave sensor or an imaging sensor, and determines a risk level described later in detail. A brake intervention command is output to the brake control unit 33. In the brake control unit 33, reference numeral 31 denotes a normal brake operation unit that controls the operation of the normal brake, and reference numeral 32 denotes an emergency brake operation unit that controls the operation of the emergency brake.

  The collision possibility determination unit 30, the torque command calculator 17, and the emergency brake controller 23 are not only an application specific integrated circuit (ASIC), but also an MPU (Micro-Processing Unit), a CPU. It may be formed by executing software for realizing the functions of the collision possibility determination unit 30, the torque command calculation unit 17, and the emergency brake control unit 23 in hardware such as (Central Processing Unit). In FIG. 3, the collision possibility determination device 30, the torque command calculator 17, and the emergency brake controller 23 are illustrated as separate members. However, the MPU, the CPU, the storage device, and the input / output device are included. The control device may be configured to execute software for realizing each function.

Next, details of the collision possibility determination unit 30 will be described. FIG. 4 is a block diagram illustrating details of the collision possibility determination unit 30. As shown in FIG. 4, the obstacle information recognition unit 54 receives the information output from the obstacle detection sensor 28 as an input, and calculates the position of the obstacle and the relative speed between the obstacle and the host vehicle by a TTC calculation unit (collision prediction). (Time calculation unit) 55. The TTC calculator 55 calculates TTC (Time To Collision) by using the position information of the obstacle and the relative speed information of the obstacle and the host vehicle as inputs. Then, the calculated TTC is output to the risk determination unit 73. Here, TTC is expressed by the following equation from the distance X _r between the host vehicle and the obstacle and the relative speed V _r .

The normal collision avoidance determination unit 71 includes the wheel speed information output from the speed detectors 9, 10, 11, and 12, the relative speed output from the obstacle information recognition unit 54, and the normal brake braking force 80 by the normal brake operation. as an input, when a normal braking when the vehicle travels at a predetermined relative velocity V _1, a first braking avoiding the host vehicle becomes the reference for determining whether or not it is possible to avoid the collision with the obstacle The limit threshold t1 (seconds) is calculated, and the calculation result is output to the risk determination unit 73. The first braking avoidance limit threshold t1 is set as a limit time by which the dump truck 100 can avoid a collision with an obstacle when the normal brake is used in the risk determination unit 73.

Further, the emergency collision avoidance determination unit 72 includes wheel speed information output from the speed detectors 9, 10, 11, and 12, relative speed output from the obstacle information recognition unit 54, and an emergency brake braking force based on an emergency brake operation. 81 as inputs, in the case of using the emergency braking when the vehicle travels at a predetermined relative speed V _1, the vehicle is a second which is a reference for determining whether or not it is possible to avoid the collision with the obstacle The braking avoidance limit threshold value t <b> 2 (seconds) is calculated, and the calculation result is output to the risk determination unit 73. The second braking avoidance limit threshold t2 is set as a limit time by which the dump truck 100 can avoid a collision with an obstacle when the emergency brake is used in the risk determination unit 73.

  The risk determination unit 73 receives the braking avoidance limit thresholds t1 and t2 as inputs, determines whether or not brake braking is necessary to avoid a collision, and is normal when it is determined that braking is necessary. Decide whether to activate the brake or the emergency brake.

A method of determining the first braking avoidance limit threshold (first threshold) t1 will be described. In order to simplify the relative speed, consider the case where the obstacle in front is a stationary object. If the distance to the obstacle is X ₁ and the speed of the host vehicle (relative speed to the obstacle) is V ₁ , the TTC is X ₁ / V ₁ . When the speed is assumed to the same, TTC as the distance X ₁ is increased becomes larger. Here, the stop distance and stop time of the host vehicle when the normal brake is operated when the host vehicle is traveling at the speed V ₁ can be calculated.

Assuming that the stop distance in this case is X ₁ ′ and the stop time is t ₁ , when normal braking is performed, time t 1 is required for the vehicle to stop, during which the vehicle advances by the distance X ₁ ′. Here, when the distance X ₁ is equal to the distance X ₁ ′, it is not possible to avoid the own vehicle colliding with an obstacle even if the normal brake is operated, if it is less than the time t1. That is, the time t1 is a first braking avoidance limit threshold value that is a reference for determining whether or not the host vehicle collides with an obstacle when the normal brake is used.

Next, how to determine the second braking avoidance limit threshold (second threshold) t2 will be described. In order to simplify the relative speed, consider the case where the obstacle in front is a stationary object. If the distance to the obstacle is X ₂ and the speed of the host vehicle (relative speed to the obstacle) is V ₂ , TTC is X ₂ / V ₂ . When the speed is assumed to the same, TTC as the distance X ₂ is increased larger. Here, the vehicle stopping distance and stop time when the subject vehicle was operated emergency brake when the vehicle is traveling at a speed V ₂ can be calculated.

Assuming that the stop distance in this case is X ₂ ′ and the stop time is t ₂ , when emergency braking is performed, time t 2 is required for the vehicle to stop, during which the vehicle advances by the distance X ₂ ′. Here, when the distance X ₂ is equal to the distance X ₂ ′, it is not possible to avoid the collision of the host vehicle with an obstacle even if the emergency brake is operated if the time is less than t2. That is, the time t2 is a second braking avoidance limit threshold value that is a reference for determining whether or not the host vehicle collides with an obstacle when the emergency brake is used.

  FIG. 5 shows a schematic diagram of a determination method of the risk determination unit 73 in the first embodiment. The normal brake is an electric brake driven by a motor, and the braking force that can be output in accordance with the speed is determined by the braking characteristics of the motor, so that the braking limit line by the normal brake for each speed is known. Further, the emergency brake is a brake by the cooperation of the electric brake and the mechanical brake, and the braking force of the mechanical brake can be found in a catalog or the like, so that the braking limit line by the emergency brake for each speed can be known. Therefore, in FIG. 5, the region where the TTC is larger than the braking limit line by the normal brake (that is, the region where the collision can be avoided by operating the normal brake) is the region (1), and the TTC is larger than the braking avoidance line by the emergency brake. An area smaller than the braking limit line by the normal brake (that is, an area where the collision can be avoided by operating the emergency brake) is an area (2), and an area where the TTC is smaller than the braking limit line by the emergency brake (that is, the collision cannot be avoided). Region) is region (3).

Next, processing performed by the risk determination unit 73 will be described with reference to FIG. FIG. 6 is a flowchart illustrating a processing procedure of the risk determination unit 73 in the first embodiment. The degree-of-risk determination unit 73 periodically executes the process shown in FIG. 6 (for example, every 500 milliseconds). The processing of danger evaluator 73 shown in FIG. 6, it is assumed that the dump truck 100 is traveling at a relative speed V ₁ with respect to the obstacle.

  As shown in FIG. 6, the risk determination unit 73 calculates the TTC calculated by the TTC calculation unit 55, the first braking avoidance limit threshold t1 calculated by the normal collision avoidance determination unit 71, and the emergency collision avoidance determination unit 72. Using the second braking avoidance limit threshold value t2 as an input, risk level determination is performed in step S101. That is, the risk determination unit 73 determines to which of the above regions (1) to (3) the TTC belongs (S101).

  When the TTC belongs to the region (1) (S102 / Yes), the risk determination unit 73 compares the TTC with the threshold t1 (S103), and if the TTC is greater than the threshold t1 (S104 / Yes), the normal Since the risk of a collision is low even without operating the brake, the process ends. On the other hand, when TTC is equal to the threshold value t1 (S104 / No), the risk determination unit 73 considers that the dump truck 100 has a high risk of colliding with an obstacle (first risk) when traveling as it is. Then, a command (normal brake automatic intervention command) for automatically operating the normal brake is output to the normal brake operating unit 31 of the brake control unit 33 (S105).

  If it is determined that the TTC does not belong to the region (1) (S102 / No), the process proceeds to step S106. When it is determined that the TTC belongs to the region (2) (S106 / Yes), the risk determination unit 73 compares the TTC with the threshold t2 (S107), and the TTC is larger than the threshold t2 (that is, t2 <TTC). If it is <t1 (S108 / Yes), the collision can be avoided at any time by operating the emergency brake. Therefore, at this time, the process ends without performing the process of operating the emergency brake. On the other hand, when TTC is equal to the threshold value t2 (S108 / No), the risk determination unit 73 considers that the dump truck 100 has a high risk of colliding with an obstacle (second risk) when traveling as it is. Then, a command for automatically operating the emergency brake (emergency brake automatic intervention command) is output to the emergency brake operating unit 32 of the brake control unit 33 (S109).

  In the case of No in step S106 (that is, when TTC <t2), TTC belongs to the region (3), and a collision cannot be avoided even if the emergency brake is operated. Therefore, in the case of No in step S <b> 106, the risk determination unit 73 immediately proceeds to step S <b> 109 and outputs an emergency brake automatic intervention command to the emergency brake operation unit 32 of the brake control unit 33.

  With the above configuration, a dump truck is automatically used with an appropriate brake at an appropriate timing to avoid a collision with a vehicle having two different types of brakes, a normal brake and an emergency brake. 100 can be braked. Further, by eliminating the brake by the mechanical brake at unnecessary timing, it is possible to suppress the wear of the tire and the disk of the mechanical brake and to reduce the frequency of parts replacement.

Second Embodiment
Next, a second embodiment of the present invention will be described. FIG. 7 is an overall configuration diagram of a dump truck 200 according to the second embodiment. As shown in FIG. 7, in the dump truck 200 according to the second embodiment, the speaker (first notification unit) 131 for notifying the operator to operate the normal brake pedal 92 and the emergency brake pedal 94 are operated. There is a feature in that a warning light (second notification unit) 132 for notifying the operator is provided. Although not shown, the speaker 131 is provided on the right side of the front panel 95 (see FIG. 2), and the warning lamp 132 is provided on the left side of the front panel 95.

  In this embodiment, the operation of the normal brake pedal 92 is notified using audio information, and the operation of the emergency brake pedal 94 is notified using visual information, but the notification modes of the first notification unit and the second notification unit are as follows. It is not limited to this. In a situation where the second notification unit prompts the operation of the emergency brake pedal 94, since the time until collision avoidance is short (the degree of urgency is high), a notification mode that is more urgent than the notification mode of the first notification unit is used. preferable. For example, when both the first notification unit and the second notification unit are notified using voice information, the volume of the second notification unit is set higher than the volume of the first notification unit. In addition, the second notification unit may notify by using both visual information and sound information by a warning light. Furthermore, you may change the frequency of the audio | voice information output from each of a 1st alerting | reporting part and a 2nd alerting | reporting part. Further, the second notification unit may be configured as a vibration device provided in the seat 90 and may prompt the operator to operate the emergency brake using vibration.

  FIG. 8 is a diagram illustrating details of the collision possibility determination unit 30A according to the second embodiment, and FIG. 9 is a diagram for explaining a risk determination method according to the second embodiment. As shown in FIG. 8, in the normal collision avoidance determination unit 71, in addition to the calculation means for the first braking avoidance limit threshold t1 described in the first embodiment, a first warning that prompts the operator to perform normal braking is provided. A means for calculating the threshold value t1 ′ is further included. The first alarm threshold value t1 ′ is a value obtained by adding a margin (for example, about 1 to 3 seconds) to the first braking avoidance limit threshold value t1, and is normally 1 to 3 seconds after the alarm is sounded from the speaker 131. A collision with an obstacle can be avoided only by operating the brake pedal 92 (normal brake notification line in FIG. 9).

  Here, the margin is the time required for the filtering process for the obstacle detection sensor 28 to detect the position of the obstacle and the speed of the dump truck 200 (relative speed between the obstacle and the dump truck 200) and the operator receives an alarm. It shows the free running time and the free running time when it is not immediately noticed even if an alarm sounds.

  The emergency collision avoidance determination unit 72 calculates a second alarm threshold t2 ′ that prompts the operator to perform emergency braking in addition to the calculation means for the second braking avoidance limit threshold t2 described in the first embodiment. The method is further provided. The second warning threshold t2 ′ is a value obtained by adding a margin (for example, about 1 to 3 seconds) similar to the above to the second braking avoidance limit threshold t2, so that 1 to 2 after the warning light 132 is turned on. The collision with an obstacle can be avoided by operating the emergency brake pedal 94 for 3 seconds (emergency brake notification line in FIG. 9).

Next, processing performed by the risk determination unit 73 in the second embodiment will be described with reference to FIG. FIG. 10 is a flowchart illustrating a processing procedure of the risk determination unit 73 in the second embodiment. The risk determination unit 73 periodically executes the process shown in FIG. 10 (for example, every 500 milliseconds). The processing of danger evaluator 73 shown in FIG. 10, it is assumed that the dump truck 200 is traveling at a relative speed V ₁ with respect to the obstacle.

  As shown in FIG. 10, the risk determination unit 73 includes a TTC calculated by the TTC calculation unit 55, a first braking avoidance limit threshold t1 and a first alarm threshold t1 ′ calculated by the normal collision avoidance determination unit 71, Using the second braking avoidance limit threshold value t2 and the second warning threshold value t2 ′ calculated by the emergency collision avoidance determination unit 72 as inputs, risk determination is performed in step S201. That is, the risk determination unit 73 determines to which of the regions (1) to (3) shown in FIG. 9 the TTC belongs (S201).

  When the TTC belongs to the region (1) (S202 / Yes), the risk determination unit 73 compares the TTC with the alarm threshold t1 ′ (S203), and if the TTC is greater than the alarm threshold t1 ′ (S204 / Yes), since the risk of a collision is low even if the normal brake is not operated, the process ends.

  On the other hand, when the TTC is equal to or less than the alarm threshold t1 ′ (S204 / No), the risk determination unit 73 compares the TTC with the threshold t1 (S205), and when the TTC is greater than the threshold t1, that is, the TTC is the threshold t1. If it is larger and is equal to or lower than the alarm threshold t1 ′ (S206 / Yes), there is a high possibility that the dump truck 200 will collide with an obstacle if it travels as it is. Command) is output to the speaker 131 (S207). The operator can avoid the collision manually by listening to the alarm and stepping on the normal brake pedal 92.

  On the other hand, if Yes in step S206, that is, if TTC is equal to the threshold value t1, the risk determination unit 73 is in a situation where the risk of colliding with an obstacle is high (first risk) when the dump truck 200 travels as it is. Assuming that there is a command, a command (normal brake automatic intervention command) for automatically operating the normal brake is output to the normal brake operation unit 31 of the brake control unit 33 (S208).

  If it is determined that the TTC does not belong to the region (1) (S202 / No), the process proceeds to step S209. When it is determined that the TTC belongs to the region (2) (S209 / Yes), the risk determination unit 73 compares the TTC with the alarm threshold t2 ′ (S210), and if the TTC is greater than the alarm threshold t2 ′. If the emergency brake is activated (S211 / Yes), the collision can be avoided at any time. Therefore, at this time, the process is terminated without performing the emergency brake activation process.

  On the other hand, when TTC is equal to or less than the alarm threshold t2 ′ (S211 / No), the risk determination unit 73 compares TTC with the threshold t2 (S212), and when TTC is greater than the threshold t2, that is, TTC is the threshold t2. If it is larger and is equal to or less than the alarm threshold t2 ′ (S213 / Yes), there is a high possibility that the dump truck 200 will collide with an obstacle if it travels as it is. Therefore, an emergency warning command (second notification) is issued to prompt the operator to perform emergency braking. Command) is output to the warning lamp 132 (S207). The operator can manually avoid the collision by stepping on the emergency brake pedal 94 while watching the warning light.

  On the other hand, in the case of No in step S213, that is, when TTC is equal to the threshold value t2, the risk determination unit 73 is in a situation where the risk of colliding with an obstacle is high (second risk) when the dump truck 200 travels as it is. Assuming that there is a command, a command (emergency brake automatic intervention command) for automatically operating the emergency brake is output to the emergency brake operating unit 32 of the brake control unit 33 (S215).

  In the case of No in step S209 (that is, when TTC <t2), TTC belongs to the region (3), and even if the emergency brake is operated, a collision cannot be avoided. Therefore, in the case of No in step S209, the risk determination unit 73 immediately proceeds to step S215 and outputs an emergency brake automatic intervention command to the emergency brake operation unit 32 of the brake control unit 33.

  With the above configuration, a dump truck is automatically used with an appropriate brake at an appropriate timing to avoid a collision with a vehicle having two different types of brakes, a normal brake and an emergency brake. 200 can be braked. By further adding a warning, it is possible to prompt the operator to perform the brake operation before automatically operating the normal brake or the emergency brake. Therefore, the dump truck 200 can be braked using the skill of the operator. Further, by eliminating the brake by the mechanical brake at unnecessary timing, it is possible to suppress the wear of the tire and the disk of the mechanical brake and to reduce the frequency of parts replacement.

<Third Embodiment>
Next, a third embodiment of the present invention will be described. FIG. 11 is an overall configuration diagram of a dump truck 300 according to the third embodiment. As shown in FIG. 11, the dump truck 300 according to the third embodiment is provided with a buzzer (third notification unit) 140 for notifying an operator that a collision with an obstacle is avoided by steering. There are features. Although not shown, the buzzer 140 is provided on the left side of the front panel 95 (see FIG. 2).

  FIG. 12 is a diagram illustrating details of the collision possibility determination unit 30B according to the third embodiment, and FIG. 13 is a diagram for explaining a risk determination method according to the third embodiment. As shown in FIG. 12, the normal collision avoidance determination unit 71 and the emergency collision avoidance determination unit 72 include the steering avoidance limit threshold value tst (seconds) in addition to the braking avoidance limit threshold values t1 and t2 described in the first embodiment. ) Is provided. The steering avoidance limit threshold value tst is a minimum time during which an operator can avoid a collision by steering, and a predetermined parameter is used according to the size of the vehicle.

As shown in FIG. 13, the magnitude relationship between the steering avoidance limit threshold value tst and the braking avoidance limit threshold values t1 and t2 varies depending on the magnitude of the relative speed. This is because when the relative speed is high (V ₁ ), it takes time until the brake is stopped after the brake is applied (the values of t1 and t2 increase), so the magnitude relationship between them is tst <t2 <t1 (FIG. 13 (a)).

When the relative speed decreases and the relative speed becomes V ₂ (<V ₁ ), the magnitude relationship becomes t2 <tst <t1 (see FIG. 13B). In this state, there is a phase in which a collision can be avoided without operating the emergency brake by performing steering even in a region where the normal brake cannot avoid. This phase exists in the range of t2 <tst <TTC.

When the relative speed is further decreased and the relative speed becomes V ₃ (<V ₂ ), the magnitude relationship becomes t2 <t1 <tst (see FIG. 13C). In this state, there is a phase in which a collision can be avoided without operating the normal brake by performing steering before operating the normal brake as well as the emergency brake.

  Next, processing performed by the risk determination unit 73 in the third embodiment will be described with reference to FIG. FIG. 14 is a flowchart illustrating a processing procedure of the risk determination unit 73 in the third embodiment. The risk determination unit 73 periodically executes the processing shown in FIG. 14 (for example, every 500 milliseconds).

  As shown in FIG. 14, the risk determination unit 73 calculates the TTC calculated by the TTC calculation unit 55, the first braking avoidance limit threshold t <b> 1 calculated by the normal collision avoidance determination unit 71, and the emergency collision avoidance determination unit 72. Using the second braking avoidance limit threshold value t2 and the set steering avoidance limit threshold value tst as inputs, risk determination is performed in step S301. That is, the risk determination unit 73 determines to which of the areas (1) to (3) shown in FIG. 13 the TTC belongs (S301).

  When the TTC belongs to the region (1) (S302 / Yes), the risk determination unit 73 compares the TTC with the steering threshold tst (S303), and if the TTC is larger than the steering threshold tst (S304 / Yes). Since a collision can be avoided by steering without operating the normal brake, a steering notification command (third notification command) is output to the buzzer 140 (S308). If the operator hears that the buzzer 140 is sounding and operates the steering handle 91, a collision can be avoided without operating the normal brake.

Incidentally, it may dump truck 300 if the vehicle is traveling at a relative speed _{V 3,} the Yes and in step S304 depending on the value of TTC, the steering notification command is output.

  On the other hand, when the TTC is equal to or less than the steering threshold tst (S304 / No), the risk determination unit 73 compares the TTC with the threshold t1 (S305), and when the TTC is greater than the threshold t1 (S306 / Yes), the normal brake Since the risk of a collision is low even without operating, the process ends.

  On the other hand, if Yes in step S306, that is, if TTC is equal to the threshold value t1, the risk determination unit 73 is in a situation where the risk of colliding with an obstacle is high (first risk) when the dump truck 300 travels as it is. Assuming that there is a command, a command for automatically operating the normal brake (normal brake automatic intervention command) is output to the normal brake operating unit 31 of the brake control unit 33 (S307).

  If it is determined that the TTC does not belong to the region (1) (S302 / No), the process proceeds to step S309. When the TTC belongs to the region (2) (S309 / Yes), the risk determination unit 73 compares the TTC with the steering threshold tst (S310), and if the TTC is larger than the steering threshold tst (S311 / Yes). Since a collision can be avoided by steering without operating the emergency brake, a steering notification command is output to the buzzer 140 (S308). If the operator hears that the buzzer 140 is sounding and performs steering by the steering handle 91, the collision can be avoided without operating the emergency brake (in this situation, the operation of the normal brake is necessary).

Incidentally, it may dump truck 300 when the vehicle is traveling at a relative speed _{V 2,} the Yes and in step S311 depending on the value of TTC, the steering notification command is output.

  On the other hand, when the TTC is equal to or less than the steering threshold tst (S311 / No), the risk determination unit 73 compares the TTC with the threshold t2 (S312), and when the TTC is greater than the threshold t2 (S313 / Yes), the emergency brake Since the collision can be avoided at any time by operating the, the process ends without performing the process of operating the emergency brake at this time.

  On the other hand, if Yes in step S313, that is, if TTC is equal to the threshold value t2, the risk determination unit 73 is in a situation where the risk of colliding with an obstacle is high (second risk) when the dump truck 300 travels as it is. Assuming that there is a command, a command (emergency brake automatic intervention command) for automatically operating the emergency brake is output to the emergency brake operation unit 32 of the brake control unit 33 (S314).

  In the case of No in step S309 (that is, when TTC <t2), TTC belongs to the region (3), and the collision cannot be avoided even if the emergency brake is operated. Therefore, in the case of No in step S309, the risk determination unit 73 immediately proceeds to step S314 and outputs an emergency brake automatic intervention command to the emergency brake operation unit 32 of the brake control unit 33.

  With the above configuration, a dump truck is automatically used with an appropriate brake at an appropriate timing to avoid a collision with a vehicle having two different types of brakes, a normal brake and an emergency brake. 300 can be braked. Further, in consideration of the limit that the collision can be avoided by operating the steering handle 91, when the avoidance by the steering is possible without operating the emergency brake, a notification for urging the steering is performed, so that the mechanical brake is The frequency of use can be lowered. Therefore, it is possible to suppress wear of the tire and the disk of the mechanical brake, and to reduce the frequency of parts replacement.

  In addition, when TTC is larger than the threshold value t1, the possibility of colliding with an obstacle is low. Therefore, when the TTC belongs to the region (1), the processes in steps S303 and S304 in FIG. 14 may be omitted. In other words, if the collision can be avoided by operating the normal brake, it is not necessary to notify the steering handle 91 of the steering.

<Fourth embodiment>
Next, a fourth embodiment of the present invention will be described. FIG. 15 is an overall configuration diagram of a dump truck 400 according to the fourth embodiment. As shown in FIG. 15, in the dump truck 400 according to the fourth embodiment, the speaker (first notification unit) 131 for notifying the operator to operate the normal brake pedal 92 and the operator operating the emergency brake pedal 94 are operated. A warning light (second notification unit) 132 for notifying the operator and a buzzer (third notification unit) 140 for notifying the operator that a collision with an obstacle is avoided by steering are provided. is there. That is, a combination of the second embodiment and the third embodiment is a dump truck 400 according to the fourth embodiment of the present invention. Although not shown, the speaker 131 is provided on the right side of the front panel 95 (see FIG. 2), and the warning lamp 132 and the buzzer 140 are provided on the left side of the front panel 95, respectively.

  FIG. 16 is a diagram illustrating details of the collision possibility determination unit 30C according to the fourth embodiment, and FIGS. 17 to 19 are diagrams for explaining a risk determination method according to the fourth embodiment. As shown in FIG. 16, the normal collision avoidance determination unit 71 sets a means for calculating the first braking avoidance limit threshold value t1 and the first alarm threshold value t1 ′, and the steering avoidance limit threshold value tst (seconds). Means. The emergency collision avoidance determination unit 72 includes means for calculating the second braking avoidance limit threshold value t2 and the second alarm threshold value t2 ′, and means for setting the steering avoidance limit threshold value tst (seconds). ing.

As shown in FIGS. 17 to 19, there is a difference in the magnitude relationship among the steering avoidance limit threshold value tst, the braking avoidance limit threshold value t2 and the alarm threshold value t2 ′ according to the magnitude of the relative speed. This is because when the relative speed is high (V ₁ ), it takes time from applying the brake to stopping (the values of t2 and t2 ′ increase), so the magnitude relationship between them is tst <t2 <t2 ′. (See FIG. 17).

When the relative speed decreases and the relative speed becomes V ₂ (<V ₁ ), the magnitude relationship becomes t2 <tst <t2 ′ (see FIG. 18). In this state, there is a phase in which a collision can be avoided without operating the emergency brake by performing steering even in a region where the normal brake cannot avoid. This phase exists in the range of t2 <tst <TTC.

  Here, in the state of tst <TTC <t2 ′, if the steering avoidance limit threshold value is ignored, an alarm for urgent braking may be sounded (warning lamp 132 is turned on) when TTC <t2 ′. . However, since this eliminates the possibility of avoiding a collision by steering, in the present embodiment, a notification that the steering is urged is first given. After that, when t2 <TTC <tst, it is impossible to avoid by steering. Therefore, an alarm for urgent braking is sounded according to the relationship between TTC and the alarm threshold t2 '.

When the relative speed is further decreased and the relative speed becomes V ₃ (<V ₂ ), the magnitude relationship becomes t2 <t2 ′ <tst (see FIG. 19). Also in this state, as in the case of FIG. 18, an alarm for prompting steering is sounded when tst <TTC is satisfied, and an alarm for prompting emergency braking is sounded when t2 <TTC <tst.

  Next, processing performed by the risk determination unit 73 in the fourth embodiment will be described with reference to FIGS. 20 and 21 are flowcharts illustrating the processing procedure of the risk determination unit 73 in the fourth embodiment. The risk determination unit 73 periodically executes the processes shown in FIGS. 20 and 21 (for example, every 500 milliseconds).

  As shown in FIG. 20, the risk determination unit 73 includes the TTC calculated by the TTC calculation unit 55, the first braking avoidance limit threshold t1 and the first alarm threshold t1 ′ calculated by the normal collision avoidance determination unit 71, Using the second braking avoidance limit threshold value t2 and the second alarm threshold value t2 ′ calculated by the emergency collision avoidance determination unit 72 and the steering avoidance limit threshold value tst as inputs, risk determination is performed in step S401. That is, the risk determination unit 73 determines to which of the areas (1) to (3) shown in FIGS. 17 to 19 the TTC belongs (S401).

  When the TTC belongs to the area (1) (S402 / Yes), the risk determination unit 73 compares the TTC with the alarm threshold t1 ′ (S403), and if the TTC is greater than the alarm threshold t1 ′ (S404 / Yes), since the risk of a collision is low even if the normal brake is not operated, the process ends.

  On the other hand, when TTC is equal to or less than the alarm threshold t1 ′ (S404 / No), the risk determination unit 73 compares TTC with the threshold t1 (S405), and when TTC is larger than the threshold t1, that is, TTC is the threshold t1. If it is larger and is equal to or less than the alarm threshold t1 ′ (S406 / Yes), there is a high possibility that the dump truck 400 will collide with an obstacle if it travels as it is. Therefore, a normal alarm command is sent to the speaker 131 to urge the operator to perform normal braking. In response to this (S407). The operator can avoid the collision manually by listening to the alarm and stepping on the normal brake pedal 92.

  On the other hand, if Yes in step S406, that is, if TTC is equal to the threshold value t1, the risk determination unit 73 is in a situation where the risk of colliding with an obstacle is high (first risk) when the dump truck 400 travels as it is. Assuming that there is a command, a command (normal brake automatic intervention command) for automatically operating the normal brake is output to the normal brake operating unit 31 of the brake control unit 33 (S408).

  If it is determined that the TTC does not belong to the region (1) (S402 / No), the process proceeds to step S409 in FIG. When the TTC belongs to the region (2) (S409 / Yes), the risk determination unit 73 compares the TTC, the steering threshold tst, and the alarm threshold t2 ′ (S410), and satisfies the relationship of TTC> tst> t2 ′. (S411 / Yes) Since a collision can be avoided by steering without operating the emergency brake, a steering notification command is output to the buzzer 140 (S412).

If the operator hears that the buzzer 140 is sounding and performs steering by the steering handle 91, the collision can be avoided without operating the emergency brake (in this situation, the operation of the normal brake is necessary). As shown in FIG. 19, when the dump truck 400 is traveling at the relative speed V ₃ , depending on the value of TTC, “Yes” may be obtained in step S 411, and a steering notification command may be output.

  On the other hand, if tst ≧ TTC> t2 ′ is satisfied (S413 / No), the collision cannot be avoided by steering, but the collision can be avoided at any time by operating the emergency brake. The process ends without performing it.

  When TTC is equal to or lower than the alarm threshold t2 ′ (S413 / No), the risk determination unit 73 compares TTC with the threshold t2 (S414), and when TTC is greater than the threshold t2, that is, TTC is the threshold t2. If it is larger and is equal to or less than the alarm threshold t2 ′ (S415 / Yes), there is a high possibility that the dump truck 400 will collide with an obstacle if it travels as it is. Therefore, an emergency warning command is issued to alert the operator to emergency braking. (S416). The operator can manually avoid the collision by stepping on the emergency brake pedal 94 while watching the warning light.

Incidentally, as shown in FIG. 18, when the dump truck 400 is traveling at a relative speed V _2, when the TTC satisfies the relation of steering threshold tst <TTC ≦ alarm threshold t2 ', the collision avoidance by the steering Even when possible, an alarm may sound to operate the emergency brake.

  On the other hand, in the case of No in step S415, that is, when TTC is equal to the threshold value t2, the risk determination unit 73 is in a situation where the risk of colliding with an obstacle is high (second risk) when the dump truck 400 travels as it is. Assuming that there is a command, a command (emergency brake automatic intervention command) for automatically operating the emergency brake is output to the emergency brake operation unit 32 of the brake control unit 33 (S417).

  In the case of No in step S409 (that is, when TTC <t2), TTC belongs to the region (3), and the collision cannot be avoided even if the emergency brake is operated. Therefore, in the case of No in step S409, the risk determination unit 73 immediately proceeds to step S417 and outputs an emergency brake automatic intervention command to the emergency brake operation unit 32 of the brake control unit 33.

  With the above configuration, a dump truck is automatically used with an appropriate brake at an appropriate timing to avoid a collision with a vehicle having two different types of brakes, a normal brake and an emergency brake. 400 can be braked. Before the normal brake or emergency brake is automatically activated, the dump truck 400 can be braked using the skill of the operator by notifying the operator that the brake operation is to be performed. In addition, by notifying that the collision can be avoided by operating the steering handle 91, the frequency of use of the mechanical brake can be reduced. Therefore, it is possible to suppress wear of the tire and the disk of the mechanical brake, and to reduce the frequency of parts replacement.

<Fifth Embodiment>
Next, a fifth embodiment of the present invention will be described. FIG. 22 is an overall configuration diagram of a dump truck 500 according to the fifth embodiment, and FIG. 23 is a diagram illustrating details of a collision possibility determination unit 30D according to the fifth embodiment. As shown in FIG. 22, in the dump truck 500 according to the fourth embodiment, a load sensor (load detector) 50 for detecting the presence or absence of a load on the loading platform 61, and an inclination sensor (for detecting the inclination of the road surface) (Tilt detector) 51.

Further, as shown in FIG. 23, the collision possibility determination unit 30D is configured to estimate a road surface state (friction coefficient) based on detection values from the speed detectors 9, 10, 11, and 12. 52. The fifth embodiment is characterized in that the braking avoidance limit threshold values t ₁ and t ₂ change according to the presence / absence of a load loaded on the loading platform 61, the presence / absence of a road surface inclination, and the road surface state. There is. The following describes how the braking avoidance limit threshold changes.

  First, a change in the first braking avoidance limit threshold due to a difference in load will be described with reference to FIG. FIG. 24 is a diagram illustrating the relationship between the presence / absence of a load and the degree of risk. In the same manner as in the first embodiment, a case where the front obstacle is a stationary object is considered in order to simplify the relative speed.

When the distance from the obstacle when the vehicle is not loaded is X ₁ (empty load) and the speed of the vehicle is V ₁ , the TTC (predicted collision time) is X ₁ (empty load) / V ₁ Here, it is possible to calculate the braking distance X ₁ ′ (empty load) when the normal brake is operated when the host vehicle is traveling at V ₁ . If the value obtained by dividing the braking distance X ₁ ′ (empty load) by the speed V ₁ of the host vehicle (collision avoidance limit of the normal brake during running with no load) is t ₁ (empty load), TTC is t ₁ (empty). Load) In the following cases, collision with obstacles cannot be avoided with normal brake alone.

Next, assuming that the distance from the obstacle when the vehicle is loaded is X ₁ (load) and the speed of the host vehicle is V ₁ , TTC is X ₁ (load) / V ₁ . Here, the braking distance X ₁ ′ (load) when the normal braking is performed when the host vehicle is traveling at V ₁ can be calculated. When a value obtained by dividing the braking distance X ₁ ′ (load) by the speed V ₁ of the own vehicle (a collision avoidance limit of a normal brake during load travel) is t ₁ (load), TTC is equal to or less than t ₁ (load). In this case, the collision with the obstacle cannot be avoided only by the normal brake.

Here, since the acceleration / deceleration of the vehicle is inversely proportional to the mass from the equation of motion, when traveling at the same speed V ₁ , X ₁ ′ (load)> X ₁ ′ (empty load), t ₁ (load)> t ₁ ( (Empty cargo) is established. This indicates that the collision with the obstacle cannot be avoided by the normal brake alone if the load is not more than X ₁ ′ (load). Therefore, when the have gained cargo by larger than the first braking avoidance limit threshold t _{1 (unloaded)} when the first brake avoidance limit threshold t _{1 (cargo)} the unladen, in cargo state Even if it exists, the normal brake operates at an appropriate timing, and collision with an obstacle can be avoided.

Regarding the change of the second braking avoidance limit threshold, the second braking avoidance limit threshold t ₂ (load) is set to the second braking at the time of empty load when a load is being loaded, similarly to the first braking avoidance limit threshold. By making it larger than the avoidance limit threshold value t ₂ (empty load), the emergency brake operates at an appropriate timing even in a loaded state, and collision with an obstacle can be avoided.

Next, a change in the first braking limit threshold due to a difference in inclination will be described with reference to FIG. FIG. 25 is a diagram illustrating the relationship between road slope and risk. A case of traveling on a flat road and a case of traveling on a downhill with an inclination θ [deg] will be compared. If the distance between the vehicle and the obstacle traveling on a flat road is X ₁ (flat) and the speed of the host vehicle is V ₁ (flat), TTC is X ₁ (flat) / V ₁ (flat). Here, it is possible to calculate the stopping distance and the stopping time when the normal braking is performed while the vehicle is running on the host vehicle V ₁ (flat). This stop distance is X ₁ ′ (flat), and the stop time is t ₁ (flat). This indicates that when normal braking is performed, it takes t ₁ (flat) to stop the vehicle, and the vehicle advances by X ₁ ′ (flat) during that time.

Next, assuming that the distance from the obstacle that the vehicle is traveling on the downhill is X ₁ (down) and the speed of the host vehicle is V ₁ (down), TTC is X ₁ (down) / V ₁ (down). . Here, it is possible to calculate the stopping distance and the stopping time when the normal braking is performed while traveling on the host vehicle V ₁ (below). This stop distance is assumed to be X ₁ ′ (lower) and the stop time is assumed to be t ₁ (lower). This indicates that when normal braking is performed, it takes t ₁ (down) to stop the vehicle, and the vehicle advances by X ₁ ′ (down) during that time. Assuming that the distance X ₁ (below) and X ₁ ′ (below) to the obstacle described above are equal, if the TTC is equal to or less than t ₁ (below), the normal brake alone will It means to collide.

When the vehicle travels on a downhill, the force of Mgsin θ parallel to the road surface caused by gravity acts on the vehicle, so that acceleration is applied to the vehicle by gsin θ excluding mass M. Therefore, it becomes difficult for the vehicle to stop by gsin θ. When V ₁ (flat) and V ₁ (bottom) are equal, X ₁ ′ (bottom)> X ₁ ′ (flat) and t ₁ (bottom)> t ₁ (flat) are satisfied.

This indicates that when the vehicle is traveling downhill and the distance between the vehicle and the obstacle is more than X ₁ ′ (down), the collision with the obstacle can be avoided only by the normal brake. Therefore, when the vehicle is traveling on a downhill, the first braking avoidance limit threshold t ₁ (below) is set larger than the _first braking avoidance limit threshold t ₁ (flat) at the time of flatness. Even if it exists, the normal brake operates at an appropriate timing, and collision with an obstacle can be avoided.

On the other hand, when the vehicle travels on the uphill, the vehicle is likely to stop by the acceleration of gsin θ opposite to the downhill, so when V ₁ (flat) and V ₁ (up) are equal as in the downhill. , X ₁ ′ (climbing) <X ₁ ′ (flat), and t ₁ (climbing) <t ₁ (flat). Therefore, when the vehicle is traveling on a downhill, the first braking avoidance limit threshold value t ₁ (climbing) is made smaller than the _first braking avoidance limit threshold value t ₁ (flat) when there is no load. Even on an uphill, the normal brake operates at an appropriate timing, and collision with an obstacle can be avoided.

  As for the change in the second braking limit threshold, similarly to the first braking limit threshold, the second braking limit threshold is larger when traveling on a downhill than the second braking limit threshold during traveling on a flat road. However, when the vehicle is traveling uphill, the emergency brake is activated at an appropriate timing corresponding to the slope of the road surface, and collision with an obstacle can be avoided.

Next, a change in the first braking limit threshold due to a difference in road surface condition will be described with reference to FIG. FIG. 26 is a diagram showing the relationship between the road surface condition and the degree of danger. A case of traveling on a high μ road with a large frictional force and a case of traveling on a low μ road with a small frictional force will be compared. TTC is X ₁ (high μ) / V ₁ (high), where X ₁ (high μ) is the distance from the obstacle when the vehicle travels on a high μ road, and V ₁ (high μ) is the speed of the host vehicle. μ). Here, it is possible to calculate the stop distance and the stop time when the normal braking is performed when the vehicle V ₁ (high μ) is running. This stop distance is X ₁ ′ (high μ), and the stop time is t ₁ (high μ). This indicates that when normal braking is performed, it takes t ₁ (high μ) to stop the vehicle, and the vehicle advances by X ₁ ′ (high μ) during that time.

Next, assuming that the distance from the obstacle when the vehicle travels on a low μ road is X ₁ (low μ) and the speed of the host vehicle is V ₁ (low μ), the TTC is X ₁ (low μ) / V _1. (Low μ). Here, it is possible to calculate the stop distance and the stop time when the normal brake is performed while the vehicle V ₁ (low μ) is running. This stop distance is X ₁ ′ (low μ), and the stop time is t ₁ (low μ). This indicates that when normal braking is performed, it takes t ₁ (low μ) to stop the vehicle, and the vehicle advances by X ₁ ′ (low μ) during that time. Here, assuming that the distance X ₁ (low μ) and X ₁ ′ (low μ) to the obstacle described above are equal, if the TTC is equal to or less than t ₁ (low μ), the obstacle only with the normal brake It means that it is not possible to avoid collisions.

Here, since the frictional force that the tire receives from the ground is represented by the multiplication of the vertical drag N that each wheel 3, 6, 7, and 8 receives from the ground and the friction coefficient μ, the magnitude of the friction coefficient μ is proportional to the braking force. . Therefore, when V ₁ (high μ) and V ₁ (low μ) are equal, X ₁ ′ (low μ)> X ₁ ′ (high μ) and t ₁ (low μ)> t ₁ (high μ) are established. To do.

This indicates that when traveling on a low μ road, if the vehicle is separated from the obstacle by X ₁ ′ (low μ) or more, the collision with the obstacle can be avoided only by the normal brake. Therefore, the first brake avoidance limit threshold t ₁ when running on a low mu road _(low mu), a first brake avoidance limit threshold t ₁ when traveling on a high mu road _(high mu) By making it larger than, it is possible to operate the normal brake at an appropriate timing according to the road surface condition and avoid collision with an obstacle.

  Regarding the change of the second braking limit threshold, similarly to the first braking limit threshold, when traveling on a low μ road, the second braking limit threshold is set to the second braking limit threshold while traveling on a high μ road. By making it larger than that, it is possible to operate the emergency brake at an appropriate timing according to the road surface condition and avoid a collision with an obstacle.

  In the fifth embodiment, the first braking limit threshold value and the second braking limit threshold value may be determined using at least one of the above-described load, road surface inclination, and road surface state.

  With the above-described configuration, in order to avoid a collision with a vehicle having two different types of brakes, a normal brake and an emergency brake, it is appropriate depending on whether there is a load, the inclination of the road surface, or the road surface condition. The dump truck 500 can be automatically braked by using a brake suitable for a proper timing. In addition, by eliminating unnecessary brakes, it is possible to suppress wear of tires and discs of mechanical brakes, and to reduce the frequency of parts replacement.

<Sixth Embodiment>
Next, a sixth embodiment of the present invention will be described. Note that the dump truck according to the sixth embodiment is the same as the first embodiment except that the obstacle is a moving body.

  A change in the first braking avoidance limit threshold when the obstacle is considered as a moving body will be described with reference to FIG. FIG. 27 is a diagram illustrating the relationship between the moving direction of the moving object and the degree of danger.

The relative speed V _r is defined by the following equation.
V ₁ is the vehicle speed, and V _obs is the speed of the obstacle. The sign of speed is positive in the traveling direction of the vehicle.

Even if the obstacle is stationary or moving, the braking distance X ₁ ′ at the vehicle speed V ₁ does not change. Therefore, a value obtained by dividing the braking distance X ₁ ′ by the relative speed V _r (normal brake collision avoidance limit) can be represented by t ₁ (still). Here, when the obstacle moves in the same direction as the host vehicle (V _obs > 0), the braking avoidance limit in the normal brake is t ₁ (same direction), and when the obstacle moves in the reverse direction (V _obs <0). The braking avoidance limit for normal braking is defined as t ₁ (reverse direction).

Next, the magnitude relationship with the braking avoidance limit t ₁ (stationary) when the obstacle is stopped will be described. As shown in FIG. 27, V _r becomes smaller when moving in the same direction, so t ₁ (same direction) becomes larger than t ₁ (stationary), and V _r when moving in the opposite direction. Since t becomes larger, t ₁ (reverse direction) becomes smaller than t ₁ (stationary).

This will be described using specific numerical values. For example, when the braking distance is 50 m when the vehicle speed is 30 km / h (8.3 m / s), t ₁ (stationary) when the obstacle is stopped = 50 / 8.3 = 6. 0s. Here, if the obstacle is traveling in the same direction at 10 km / h (2.8 m / s), the vehicle speed should be 40 km / h (11.1 m / s) in order to make the relative speed the same. Since the braking distance at this time is 70 m, t1 (same direction) = 70 / 8.3 = 8.4 s.

  Next, when the obstacle travels in the opposite direction at 10 km / h, the vehicle speed becomes 20 km / h (5.6 m / s) to make the relative speed the same, and the braking distance at this time Is 30 m, so t1 (same direction) = 30 / 8.3 = 3.6 s.

Therefore, when the obstacle is moving in the same direction, the first braking avoidance limit threshold t ₁ (same direction) is compared with the _first braking avoidance limit threshold t ₁ (static) when the obstacle is stopped. increase Te, the first brake avoidance limit threshold t ₁ when the obstacle a first brake avoidance limit threshold t _{1 (backward)} when the obstacle is moving in the reverse direction is stopped _(stationary) By making it smaller than the normal brake, the normal brake can be operated at an appropriate timing in consideration of the relative speed with the moving obstacle. Therefore, even when the obstacle is moving in the same direction as the host vehicle and when moving in the opposite direction, collision with the obstacle can be avoided.

Similarly to the first braking avoidance limit threshold, when the obstacle moves in the same direction, the second braking avoidance limit threshold changes to the second braking avoidance limit threshold t ₂ (same direction). The second braking avoidance limit threshold value t ₂ (reverse direction) is increased when compared with the second braking avoidance limit threshold value t ₂ (stationary) when the vehicle is stopped, and the obstacle is moving in the reverse direction. Even if it is a moving obstacle, the emergency brake is activated at an appropriate timing by making it smaller than the _second braking avoidance limit threshold t ₂ (stationary) when the object is stopped. Collisions can be avoided.

  As described above, according to the dump truck according to each embodiment described above, the normal brake and the emergency brake can be actuated at an appropriate timing to avoid collision with an obstacle. Further, since unnecessary emergency brake operation can be prevented, wear of brake discs and tires can be prevented. Therefore, the maintenance burden can be reduced.

  The above-described embodiment is an example for explaining the present invention, and is not intended to limit the scope of the present invention to the above-described embodiment. Those skilled in the art can implement the present invention in various other modes without departing from the gist of the present invention.

  For example, the present invention can be widely used in general vehicles that carry a work in a mine and are equipped with a plurality of brake devices having different braking forces.

  Further, although the embodiment of the manned dump truck on which the operator is boarded has been described, the present invention can also be applied to an unmanned dump truck that travels autonomously. In addition, in a mine where multiple unmanned dump trucks travel, it is also possible to transmit brake device operation information to the control station wirelessly or by wire, and control the travel of other unmanned dump trucks from the control station based on that information. .

24-27 Mechanical brake (emergency brake device)
28 Obstacle detection sensor (obstacle detection device)
30, 30A-D Collision possibility judgment device (collision possibility judgment part)
33 Brake control unit 50 Load sensor (load detector)
51 Tilt sensor (Tilt detector)
52 Road surface state estimation calculation unit 54 Obstacle information recognition unit 55 TTC calculation unit (collision prediction time calculation unit)
73 Risk determination unit 91 Steering handle (handle)
92 Normal brake pedal (normal brake device)
94 Emergency brake pedal (emergency brake device)
131 Speaker (first notification unit)
132 Warning light (second notification part)
140 buzzer (third notification unit)

Claims (9)

A handle operated by an operator;
An obstacle detection device for detecting obstacles;
A normal brake device used during normal braking,
An emergency brake device used during emergency braking;
A first notification unit for performing notification for prompting operation of the normal brake device;
A second notification unit for performing notification for prompting operation of the emergency brake device;
A third notification unit for performing notification for prompting operation of the handle;
A collision possibility determination unit that determines the possibility of collision with the obstacle based on the detection result of the obstacle detection device;
A brake control unit for controlling the operation of the normal brake device and the emergency brake device,
The collision possibility determination unit is configured to operate the emergency brake device in order to avoid a collision with the obstacle, or a first risk level that can avoid a collision with the obstacle by operating the normal brake device. Determine which of the two risk levels,
The brake control unit operates the normal brake device based on the determination with the first risk, operates the emergency brake device based on the determination with the second risk ,
The collision possibility determination unit
From the detection result of the obstacle detection device, an obstacle information recognition unit for calculating a distance between two points between the obstacle and a relative speed with the obstacle;
A collision prediction time calculation unit that calculates the collision prediction time by dividing the distance between the two points obtained by the obstacle information recognition unit by the relative speed;
A first threshold value set as a limit time that can be used to avoid collision with the obstacle by operating the normal brake device, and a limit time that can be set to avoid collision with the obstacle by operating the emergency brake device The set second threshold value and the predicted collision time are respectively compared, and when the predicted collision time is substantially equal to the first threshold value, the first risk is determined, and the predicted collision time is the second time. A risk determination unit that determines that the second risk is approximately equal to the threshold,
The risk determination unit
When the predicted collision time becomes substantially equal to a first warning threshold value obtained by adding a predetermined margin to the first threshold value, a first notification command is output to the first notification unit;
A second notification command is output to the second notification unit when the predicted collision time is substantially equal to a second warning threshold value obtained by adding a predetermined margin to the second threshold value;
When the predicted collision time is smaller than the first warning threshold and larger than the second warning threshold, and when it is determined that a collision with the obstacle can be avoided by an operation of the handle by an operator, the first 3 A third notification command is output to the notification unit,
The first notification unit performs notification based on the first notification command,
The second notification unit performs notification based on the second notification command,
The third notification unit performs notification based on the third notification command,
The notification by the third notification unit is performed after the notification by the first notification unit and before the notification by the second notification unit . In claim 1,
A load detector for detecting the presence or absence of a load;
The risk determination unit determines the first risk and the second risk based on the first threshold and the second threshold whose values are changed according to the detection value of the load detector. Mining dump truck characterized by. In claim 2,
When the first threshold value and the second threshold value when there is a load are changed to values larger than the first threshold value and the second threshold value when there is no load, respectively. Compared to the above, a dump truck for mining characterized in that the timing of the brake control unit operating the normal brake device and the emergency brake device is advanced. In claim 1 ,
A slope detector for detecting the slope of the road surface;
The risk determination unit determines the first risk and the second risk based on the first threshold and the second threshold whose values are changed according to the detection value of the inclination detector. Mining dump truck characterized by. In claim 4 ,
The road surface is inclined downward by changing the first threshold value and the second threshold value when the road surface is downwardly inclined to values larger than the first threshold value and the second threshold value when the road surface is upwardly inclined. The mine dump truck is characterized in that in this case, the timing at which the brake control unit operates the normal brake device and the emergency brake device is advanced as compared with the case where the road surface is climbing and inclined. In claim 1 ,
The collision possibility determination unit includes a road surface state estimation calculation unit that calculates a friction coefficient of the road surface,
The risk determination unit is configured to determine the first risk and the second risk based on the first threshold and the second threshold, the values of which are changed according to the friction coefficient calculated by the road surface state estimation calculation unit. A dump truck for mining characterized in that it is judged. In claim 6 ,
By changing the first threshold value and the second threshold value when the road surface has a low friction coefficient to values larger than the first threshold value and the second threshold value when the road surface is a high friction coefficient, the road surface is The mine is characterized in that the timing of the brake control unit operating the normal brake device and the emergency brake device is earlier in the case of a low friction coefficient than in the case of the road surface having a high friction coefficient. Dump truck. In claim 1 ,
A normal brake pedal as the normal brake device;
An emergency brake pedal as the emergency brake device,
The dump control truck according to claim 1, wherein the brake control unit receives an operation of the normal brake pedal and the emergency brake pedal by an operator and controls the operations of the normal brake device and the emergency brake device. In claim 1 ,
The obstacle information recognition unit recognizes a vehicle traveling ahead as the obstacle, and calculates a distance between two points with the traveling vehicle and a relative speed with the traveling vehicle. Mining dump truck characterized by.