JPS5927314A - Operation controlling method in detecting obstacle, of unattended cargo work vehicle - Google Patents

Abstract

PURPOSE:To raise the work efficiency, by controlling an operation of a vehicle in accordance with a distance between a vehicle and an obstacle, and a car speed, so that it does not occur that the vehicle stops whenever an obstacle is detected. CONSTITUTION:A distance signal S1 between a vehicle and an obstacle, from an obstacle detecting sensor 6 installed to the vehicle, and a car speed signal S2 from a car speed detecting sensor 9 are supplied to a CPU 10, and are compared and discriminated. Subsequently, the CPU 10 decelerates a car speed in accordance with the distance signal and the car speed signal, and thereafter, outputs a damping signal and stops the vehicle. Also, when the obstacle is shunted in the course of deceleration or in the course of damping, the vehicle is reset to its original running state. By controlling an operation of the vehicle in this way, it is unnecessary to stop the vehicle whenever an obstacle is detected, therefore, the work efficiency can be raised.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a driving control method when an obstacle is detected in an unmanned cargo handling vehicle.

Conventionally, unmanned forklifts that are guided automatically along guidance cables that have been laid out in advance at work sites have a bumper installed at the rear end, and when this bumper hits an obstacle, a limit switch or the like is activated to stop the vehicle. That's what I was doing. However, this stopping device when detecting an obstacle poses a risk of the vehicle body colliding with the obstacle due to a longer braking distance, especially if the vehicle stops after the bumper hits an obstacle while reversing at high speed. . Furthermore, since the bumper is subject to constraints on the horizontal and vertical widths, it is not possible to widen the area for detecting obstacles, and there is therefore a risk that the vehicle will collide with an obstacle while the vehicle is in an unbraked state while traveling backwards.

In order to solve this problem, there has conventionally been a device in which an ultrasonic obstacle sensor for detecting an obstacle is provided at the rear of a vehicle, and the vehicle is stopped when an obstacle is detected. However, since this device stops the vehicle every time it detects an obstacle, not only does the frequency of stops increase and work efficiency decreases, but also the load on the forks may be damaged if the system suddenly switches from high speed to stop. However, there was a defect that caused the load to collapse.

The purpose of this invention is to use a computer to compare and determine a distance signal between the vehicle and the obstacle output from an ultrasonic obstacle sensor attached to an unmanned cargo handling vehicle and a vehicle speed signal output from a vehicle speed sensor. By decelerating the vehicle speed in response to both of the above signals and then stopping the vehicle, and returning to the original running state when an obstacle retreats during deceleration or braking, work can be done with fewer stopping operations when an obstacle is detected. It is an object of the present invention to provide a driving control method when an obstacle is detected in an unmanned cargo handling vehicle, which can improve efficiency, prevent cargo from collapsing, and improve safety.

Hereinafter, one embodiment of this invention in an unmanned forklift truck will be explained with reference to FIGS. 1 and 2.
is an unmanned forklift that is guided unmanned along a guidance cable (not shown) laid in advance on the ground E, and has a mast 3 erected at the front of the vehicle body 2;
A fork 5 is moved up and down by a lift cylinder 4.
is installed. This forklift 1 is designed to move backward during normal driving in order to improve the stability of the load during braking.

An obstacle sensor 6 is installed at the rear of the vehicle body 2 to detect whether or not an obstacle M is present while the forklift is moving backward. As shown in FIG. 2, this obstacle sensor 6 includes a transmitter 7 that emits ultrasonic waves and a receiver 8 that receives reflected waves from the obstacle M, and measures the time from transmission to reception. , an obstacle M from the rear end of the vehicle body 2
It outputs a signal depending on the distance.

On the other hand, the drive motor (not shown) of the forklift 1 includes
A vehicle speed sensor 9 is provided to measure the rotational speed and detect the vehicle speed. A computer 10 is connected to the obstacle sensor 6 and the vehicle speed sensor 9, and compares and discriminates the distance signal S1 with a vehicle speed signal S2 output from the vehicle speed sensor 9, and outputs various operation signals. There is. An auto accelerator 11 is connected to the computer 10, and the vehicle speed is changed from low speed (0, 5 & shoulder/11) to medium speed (21 m/11) according to the speed change signal S3 from the computer 10.
) and high speed (4km/f+).

Further, a solenoid 13 for operating the foot brake 12 is connected to the computer 10, and is operated by a braking signal S4 from the computer 10.

Similarly, a solenoid 15 of a non-excited electromagnetic brake 14 mounted on the drive motor (the path shown) is connected to the computer 10.

When the second brake 12 is activated, the electromagnetic brake 14 is de-energized after a certain period of time, and the vehicle is braked by the foot brake 12 and the electromagnetic brake 14, creating a dual safety brake.

Furthermore, a horn 16 is connected to the computer 10, and when an obstacle is detected by the obstacle sensor 6, the computer outputs an alarm signal s6 to notify a dangerous situation. .

A bumper 17 is attached to the lower rear end of the forklift, and when the bumper 17 comes into contact with an obstacle, the vehicle is braked to a stop.

Next, the operation of the control device configured as described above will be explained.

Now, when the forklift is reversing at high speed,
When the distance between the rear of the vehicle and the obstacle M becomes 2 m, the computer 10 outputs a speed change (deceleration) signal S3, the auto accelerator 11 decelerates the vehicle from high speed to low speed, and the alarm signal S6 activates the horn 16. , the danger is announced. Further, when the forklift moves backward at low speed and the distance becomes 1 m, the computer 10 outputs a stop signal to the drive motor (as shown in the diagram) and also outputs a brake signal S.
4 is output and the foot brake 12 and electromagnetic brake 14
is activated, so that the forklift truck travels a certain distance and then stops.

On the other hand, when the distance signal S1 of 2 m is output from the obstacle sensor 6 and the obstacle is again separated from the vehicle body 2 by 2 m or more while the high speed is switched to the low speed, the computer 10
A gear change (speed increase) signal S3 is output from the auto accelerator 1.
1 is switched from low speed to high speed and returned to the original high speed state, and at the same time, the alarm signal S6 is also canceled and the horn 16 is switched from low speed to high speed.
will be stopped. Similarly, when the obstacle sensor 6 outputs a distance signal 81 of 1 m and the forklift is in a braking state, if the obstacle is 1 m or more away from the vehicle body, a braking signal S
4 is released, an operating signal is output from the computer 10 to the drive motor to return to low-speed driving, and when @1lIL is further away by 2 m or more, a speed change (speed increase) signal S is released.
8, the speed is returned from medium speed to high speed, and at the same time, the alarm signal 86 is canceled and the horn 16 is stopped.

Next, a case will be explained in which the obstacle sensor 6 detects an obstacle while the forklift is moving backward at medium speed. When becomes 1m, computer 1
A speed change (deceleration) signal S3 is output from 0 to reduce the speed from medium speed to low speed, and the horn 16 is activated by an alarm signal S6.

Thereafter, when the distance signal S1 reaches 0.5 m, a stop signal is output from the computer 10 to stop the drive motor, and a braking signal S4 is output to activate the foot brake 12 and the electromagnetic brake 14.

When the distance signal 81 of 1 m is output from the obstacle sensor 6 and the distance is 127z or more in a state where the speed is changed from medium speed to low speed, the computer 10 outputs a speed change (speed increase) signal S3 and the speed is changed to low speed. The speed is switched from to medium speed, and the horn 16 is stopped. Similarly, 0.5 m from sensor 6
When the distance signal S1 is output and the forklift is in a braking state, when the distance signal S1 becomes Q,5m1 or more,
When the braking signal s4 is released, an operating signal is output from the computer 1o to the drive morph (the path shown) to move the forklift backwards at low speed, and a speed change (speed increase) signal S is output.
3, the speed is increased from low speed to medium speed, and at the same time, the horn 16 is stopped.

Next, when the obstacle sensor 6 detects an obstacle M while the forklift is moving backward at low speed, when the distance signal s1 output from the sensor 6 reaches 1772, the computer 1o outputs an alarm signal S6. horn 1
6 is activated, but since it is at the lowest speed, deceleration cannot be performed. After that, when the distance signal S1 reaches 0.5 m, a stop signal is output from the computer 1o to stop the drive motor, and a braking signal s4 is output to start braking, and the forklift!・is stopped at a distance of 0.35m. (The horn 16 is intermittently activated.

) Also in the case of this driving control, the obstacles are from vehicle body 2 to Q and 5.
If the vehicle goes beyond 7/J, the vehicle will return to low speed while sounding its horn, and if it goes beyond 17/J, the horn will stop operating.

The forklift operation control described above is summarized in the following table.

In this way, in the embodiment of the present invention, the computer 1o compares and determines the distance signal S1 from the obstacle sensor 6 and the vehicle speed signal S2 from the vehicle speed sensor 9, and determines the length of the distance signal s1 and the high and medium speed signals of the vehicle speed signal s2. Since the forklift is decelerated and then braked according to the situation, it is no longer necessary to apply braking to stop the forklift every time it temporarily passes through an obstacle, which improves work efficiency and reduces the burden caused by stopping. You can also reduce the amount of slippage.

Note that the present invention can also be embodied in the following embodiments.

(1) A front and/or rear obstacle sensor (illustrated path) is attached to the upper part of the mast 3 of the forklift, a distance signal from the sensor is input to the computer 10, and based on changes in this distance signal, To perform a control operation that is almost the same as the operation control operation described above.

(2) Lighting a warning lamp instead of or together with the horn 16. Also, the horn 16 and warning lamp may be omitted.

As detailed above, the present invention provides an unmanned cargo handling vehicle with a distance signal and a vehicle speed signal between the vehicle and the obstacle output from an ultrasonic sensor for detecting obstacles in front and/or rear. Since the operation of the vehicle is controlled based on the system, there is no need to stop the vehicle every time an obstacle is detected, which has the effect of improving work efficiency and reducing the amount of cargo shifting. .

[Brief explanation of the drawing]

FIG. 1 is a right side view showing an embodiment of an unmanned forklift used in the traveling control method of the present invention, and FIG. 2 is a block circuit diagram showing a control device. Obstacle sensor 6, vehicle speed sensor 9, computer 10, auto accelerator 11, foot brake 12, horn 16,
Distance signal S1, vehicle speed signal S2, gear change signal S3, braking signal S4, distance L, obstacle M0 Patent applicant Toyota Industries Corporation Meidensha Co., Ltd.

Claims (1)

[Scope of Claims] 1. Vehicle and obstacles output from an ultrasonic obstacle sensor for detecting obstacles in front and/or rear provided on an unmanned cargo handling vehicle that is guided along a guidance cable. The computer compares and determines the distance signal between objects and the vehicle speed signal output from the vehicle speed sensor, and when the distance signal reaches a certain value, the vehicle speed is decelerated, and when the distance signal becomes even smaller, the computer applies the brakes. An unmanned cargo handling system that outputs a signal to stop the vehicle, and when the distance signal increases due to the removal of an obstacle, increases the vehicle speed or stops braking to return to the original running state. A driving control method when detecting an obstacle in a work vehicle. 2. When an obstacle is detected in the unmanned cargo handling vehicle according to claim 1, the computer outputs a warning signal and activates a horn and/or a warning lamp when the unmanned cargo handling vehicle approaches an obstacle by a certain distance. operation control method. 8. When a forklift truck that can change speeds in three stages: high speed, medium speed, and low speed is moving backwards at high speed, if the obstacle sensor detects an obstacle approximately 2 meters ahead, the vehicle speed is reduced from high speed to low speed, and then 2. A driving control method for an unmanned cargo handling vehicle when an obstacle is detected as claimed in claim 1, wherein a braking signal is output from the computer when a distance signal of about 1 m is output from the sensor. 4 When a forklift truck that can change speeds in three stages: high speed, medium speed, and low speed is moving backwards at medium speed, if the obstacle sensor outputs a distance signal of about 1 m, the computer outputs a speed change signal and changes from medium speed to medium speed. Obstacle detection in an unmanned cargo handling vehicle according to claim 1, wherein a braking signal is output from a computer when the sensor decelerates to a low speed and then a distance signal of about Q, 5772 is output from the sensor. Time operation control method. 5 Approximately 0.0 from the obstacle sensor when reversing at low speed.
2. A driving control method for an unmanned cargo handling vehicle when an obstacle is detected as set forth in claim 1, wherein a braking signal is output from the computer when a distance signal of 5 m is output.