JPH0443282B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an unmanned vehicle steering device such as a forklift.

Conventionally, unmanned forklifts, trolleys, etc. that can be remotely guided have been used to transport goods in and out of facilities such as cold storage warehouses and solid waste storage facilities where it is difficult for workers to directly enter and work. There are two ways to guide the vehicle: an induction wire is buried in the floor, a detection coil is installed in the vehicle, and the vehicle travels along the induction wire, and an optical reflective tape is placed on the floor instead of the induction wire. It is known that the vehicle is equipped with a detection sensor and the vehicle runs along the optical reflective tape; however, in the case of the former method, induction wires are buried in the floor. Therefore, there are drawbacks such as the large-scale construction work, poor running accuracy due to the influence of the foundation reinforcement of the buried floor, magnetic materials such as buried pipes, etc. In the latter case, it is difficult to pass wheels, carry goods in and out However, there were disadvantages in that it was difficult to maintain long-term quality, such as staining and peeling of the tape.

The present invention was proposed in view of the above circumstances, and aims to provide a highly reliable and easy-to-maintain unmanned vehicle steering device such as a forklift. A device that detects the position of a vehicle on a driving route from the distance traveled by counting pulses and steers the vehicle accordingly, and is installed on the ceiling directly above the driving route along the same driving route. a plurality of optical marks each having a predetermined length; at least two one-dimensional cameras disposed on the vehicle at intervals in the direction of vehicle travel for individually detecting the optical marks; A position determining device detects the position of the vehicle from the detection signal and the distance traveled, and a control circuit corrects the attitude angle based on the angular velocity signal of a gyroscope attached to the vehicle in response to the signal from the one-dimensional camera. It is characterized by

The present invention will now be described with reference to the most preferred illustrated embodiment.

First, in FIGS. 1 and 2, 1 is a forklift, 2 is a running wheel, and 3 is a sensor for detecting the rotational speed or rotation angle of the running wheel 2, which generates a pulse at every fixed angle. 4 is Jairo,
Thereby, the angular velocity around the vertical axis when the forklift 1 is traveling is detected. 5 and 6 are one-dimensional cameras installed on the forklift 1 to detect marks 10 on the ceiling of the building. One-dimensional camera 5, 6
As the name suggests, a plurality of light-receiving elements are arranged one-dimensionally in an image-receiving section. As in a normal television camera, each light receiving element generates an electromotive force according to the amount of light received, and from the position of the light receiving element that produces the maximum electromotive force, it connects to each of the one-dimensional cameras 5 and 6 and the mark 1.
A signal indicating the relative positional relationship of 0 is obtained. In this embodiment, as shown in FIG.
6 are respectively installed on the center of the vehicle body of the vehicle, that is, the forklift 1, and the marks 10
and the one-dimensional cameras 5 and 6.
Since the vertical distance is also fixed, the deviation in the vehicle width direction between the center of the vehicle body of the forklift 1 and the travel course where the mark 10 is located is expressed as the detection signal of the one-dimensional cameras 5 and 6. That is, the one-dimensional camera 5,
6 outputs a vehicle width direction deviation signal at the mounting position.

Further, since the mark 10 has a predetermined length as described later, the actual traveling distance can be calculated using the rising signal and falling signal of the mark 10 captured by the one-dimensional camera 5 or 6. A correction signal can be output. Furthermore, by counting the rising and falling signals, the number of marks 10 that the forklift 1 has passed can be known.

Furthermore, 7 is a front detector, which detects luggage in front of the traveling path.
Detect obstacles, etc. A load height detector 8 detects the load height of the stored articles at the forklift unloading or loading position. 9 is a control device;
Its configuration will be explained with reference to FIG. Reference numeral 10 denotes a plurality of marks placed at a predetermined length on the ceiling surface of the building, and these marks are made of optical reflective tape, stainless steel plate, or the like.

In FIGS. 1 and 2, other detectors necessary for the operation of a typical forklift are omitted, assuming that they are equipped.

In FIG. 3, numeral 10 indicates a mark placed on the ceiling of the building directly above the running courses 11 and 11' of the forklift 1 with a predetermined length and at intervals along the running courses 11 and 11'. . Reference numeral 12 denotes a loading platform, into which stored articles are supplied by a device not shown separately. 13 is a waiting station for the forklift 1.

In FIG. 4, the control device 9 includes an A/D converter 21 that converts the angular velocity of the forklift from the gyro 4 into an analog signal and a digital signal;
an adder 22 that adds the signals of the A/D converter 21;
Clock generator 2 that creates timing for adder 22
3. A signal processing device 24 that processes signals from the one-dimensional cameras 5 and 6 receives an instruction direction from a master control unit 26 (to be described later), a gyro direction from the gyro 4, and an azimuth correction signal from the signal processing device 24, and processes them. A comparison calculation device 25 that performs a comparison calculation of It is composed of a correction calculation device 28 and a position determination device 29.

The radius of the traveling wheels 2 changes not only due to wear caused by traveling, but also due to the load caused by the cargo carried by the forklift 1. Therefore, even if the forklift 1 travels the same distance, the number of signals generated by the sensor 3 will change. do.
On the other hand, since the length of the mark 10 does not change, the signal from the one-dimensional camera 5 is intermittently sent to the counter 27 to obtain a correction count.

The correction calculation device 28 uses the correction count and the new count of the sensor 3 to calculate the actual travel distance.

The position determining device 29 determines the position of the forklift 1 by combining the corrected travel distance and the reading signal of the mark 10 from the one-dimensional camera 5.

The azimuth correction signal is calculated and output as an angle (attitude angle) signal with respect to the travel route based on the vehicle width direction deviation detection signal of each of the one-dimensional cameras 5 and 6 and the mounting interval of the one-dimensional cameras 5 and 6. . 3
0 is a servo amplifier for the steering servo motor 31, 31 is a steering servo motor for turning the forklift 1, 32 is a known transmission device such as a guided radio or an optical transmission device, and 33 is a front detector 7, which detects the height of the cargo. sensor control signals for the detector 8 and other detectors (not shown) necessary for the operation of the forklift 1, and 34 is a control signal for the drive motor (not shown).

In this embodiment configured in this way, the third
The operation will be explained based on the arrangement shown in the figure. First, the time when the forklift 1 is stopped at the standby station 13 is defined as the origin.

At the same time as the forklift 1 is powered on by a separate means, the one-dimensional cameras 5 and 6 read the mark 10 on the reference travel route on the ceiling surface. Specifically, the distance between the respective positions of the one-dimensional cameras 5 and 6 and the reference driving route, that is, the positional deviation in the width direction of the vehicle (front, rear) is detected.

In this way, it is possible to determine how much azimuth deviation the forklift 1 has in its stopped state with respect to the standard travel course on which the mark 10 is provided, that is, the inclination (attitude angle) of the vehicle width line of the forklift 1 with respect to the original travel direction. ) is calculated by the signal processing device 24, and inputs the correction amount to the comparison calculation device 25,
The initial setting of the dial 4 is performed and preparation for starting is completed.

A start-ready signal is sent to a ground station (not shown) via the transmission device 32, and a work command is transmitted from the ground station to the forklift 1 via the transmission device 32. In FIG. 3, for example, if the load on the receiving platform 12 is to be stored at an arbitrary position, for example, the second row from the top, second from the left (FIG. 3), this work mode and its address are transmitted to the control device. 9 master control unit 26
to go into.

In the master control unit 26, as the first step of the work, the forklift 1 moves straight from the position of the waiting station 13 to the loading platform 12 (assumed to be N ₂ meters), and after performing the predetermined loading operation, The operation step of returning to the standby station 13 is determined, and as a result, a drive motor control signal 34 that controls the traveling direction (forward or backward) and traveling speed is sent to a traveling drive device (not shown), and the forklift 1 starts. . On the other hand, for steering operation, an instruction corresponding to the position issued from the master control unit 26 is input to the comparator 25, and the adder 22 of the gyro signal
The output of servo amplifier 30 is compared with the output of
This is done by outputting the signal to the steering servo motor 31 and driving the steering servo motor 31. The attitude angle signal that is intermittently input from the signal processing device 24 is sent to the adder 2 described above.
The output of adder 2 is compared with the output of adder 2, and based on this, adder 2
The attitude angle indicated by the output No. 2 is adjusted so as to match the attitude angle actually measured by the one-dimensional cameras 5 and 6 and the signal processing device 24. Since the distance between the end of the mark 10 placed on the ceiling directly above the waiting station 13 and the cargo receiving platform 12 is determined to be N ₂ meters due to the arrangement, the forklift 1 starts and the one-dimensional camera 5 The counter 27 counts the signal from the running sensor 3 from the falling point of the mark 10 reading signal, and the count value is input to the correction calculation device 28. Here, the count value is calibrated using a pre-stored correction count, the left and right sides are averaged, and the calibrated value average signal is input to the position determining device 29 to determine the position. Next, the determination signal is input to the master control unit 26, and a change in speed instruction and a stop command are outputted as a drive motor control signal 34.

When the forklift 1 arrives at the loading platform 12,
According to a series of operation steps of the cargo picking operation, the master control unit 26 outputs a drive motor control signal 34 to perform sequence control of lift, reach operations, etc.

After receiving the cargo, forklift 1 is operated in the reverse order of the above process.
moves backward and returns to the waiting station 13.

In the next second step, the forklift 1 moves straight the distance from the waiting station 13 to the main course 11 (assumed to be N ₁ meter), turns 90 degrees to the left, then goes straight on the main course 11' and reaches the second from the top. At the turning point for approaching the row (Fig. 3), that is, the mark 10 on the main line course 11', turns 90 degrees to the left at the fourth point, enters the branch line course 11, and moves to the predetermined position in the second row (2nd position). It is determined that the operation process is to move forward a distance (N _x meters as the distance from the waiting station 13) to the above-mentioned location, perform the prescribed unloading work after arriving, and then return from the waiting station, and as a result, The drive motor control signal 34 from the master control unit 26 is sent to a travel drive device (not shown), and the forklift 1 starts again.
When the vehicle moves forward by ₁ meter, the master control unit 26 issues a left 90° turn command, and the comparator 25 calculates the result and sends the output to the servo amplifier 30, which controls the steering servo motor 3.
1 is driven and rotated. After a 90° turn, main course 1
1', and at this time, the one-dimensional camera 5 reads the mark 10 placed on the ceiling surface, and counts the output of the travel distance sensor 3 from the rise of the signal to the fall of the signal. Since the length of the mark 10 is constant and the geometrical relationship between the mark 10 and the one-dimensional camera 5 is fixed, the distance traveled by the forklift 1 from the rise to the fall of the signal is constant. It should be. However, as described above, since the radius of the running wheels changes depending on the load and other conditions, the count value of the output of the sensor 3 also changes. This count value is calculated by the correction calculation device 28
The data is sent to and stored, and is used as correction data (correction count) for calculating mileage. As mentioned above, this value changes depending on the cargo and other conditions, so each time you pass under mark 10,
Updated.

Next, the turning point for entering the branch course 11 is determined by reading the mark 10 with the one-dimensional camera 5 when going straight on the main line course 11' and counting four marks 10. A 90° left turn command is input from the master control unit 26 to the comparator 25, which is compared with the attitude angle represented by the output of the gyro signal adder 22, and the result is sent via the servo amplifier 30. The signal is transmitted to the steering servo motor 31 and causes the forklift 1 to turn. In addition, the one-dimensional camera 5,
6 and the mark 10 come into a predetermined geometrical relationship, the attitude angle actual measurement signal is output from the signal processing device 24, as described above, and enters the comparison calculation device 25, where it is input to the gyro signal adder 22. The output of the adder 22 is finally corrected. When turning, it is determined that the forklift 1 has entered the branch course 11 based on the 90° turn completion signal of the gyro 4 or the position signal of the forklift 1 based on the output from the travel distance sensor 3, and the sensor is activated by the master control unit 26. A control signal 33 is issued to activate the forward detector 7.

In addition, the signal read by the one-dimensional camera 5 of the mark 10 installed on the ceiling is input to the position determination device 29, and the driving distance is determined from the falling signal of the second mark from the turning point entering the second row (described above). When the actual travel distance N _x meters of the sensor 3 is determined, the signal is input to the master control unit 26, and the master control unit 26 sends a drive motor control signal 34 to a travel drive device (not shown), which controls the forklift 1. At the same time as stopping traveling, the load height detector 8 is activated by the sensor control signal 33, the load height at the unloading position is confirmed, and the load height detector 8 is activated by the master control unit 26 according to a series of operation steps of the unloading operation. A motor control signal 34 is output to perform sequence control such as lift and reach operations.

When the unloading operation is completed, the master control unit 26 sends a drive motor control signal 34 instructing reverse movement to a traveling drive device (not shown), and the forklift 1 starts moving backward. As the vehicle moves backward, the counter related to distance calculation based on the reading signal of the mark 10 of the one-dimensional camera 5 and the signal of the travel distance sensor 3 is subtracted.

Turning from branch course 11 back to main course 11' and from main course 11' to waiting station 1
The turning to return to No. 3 is similar to that explained in the above-mentioned forwarding movement, and the master control unit 26 receives a signal from the position determination device 29 for each turning start point, issues a turning command from the master control unit 26, and performs steering. Then, the forklift 1 returns to the waiting station 13, and one process of loading and unloading work is completed.

According to the present embodiment described above, the following effects can be achieved.

(1) Accuracy errors caused by disturbances (wheel wear, slippage, fluctuations in load conditions, etc.), which were considered to be a drawback of distance detection using output pulse counts from sensors attached to the vehicle, are corrected by optical detection using a one-dimensional camera. At the same time, it became possible to mutually check and monitor signals, and detect driving abnormalities.

Furthermore, since the positional accuracy is good, the starting position of a course change (turning, etc.) of the traveling route can be clearly determined.

(2) The zero point error of the gyro can be automatically corrected by the optical detection of the one-dimensional camera, whether the vehicle is stopped or running, without making any circuit adjustments.

(3) Marks for one-dimensional cameras are not affected by dirt such as vehicle tire tracks, so they do not need to be repaired over a long period of time.

(4) Even in the event of an earthquake, the system will not go down due to wire breakage, unlike the buried wire method.

(5) Compared to the conventional buried wire guidance method, the on-site construction work is smaller. In addition, when expanding equipment, it can be easily done because there is less interference with the building.

As described above in detail with respect to the embodiments, the present invention enables the position of the vehicle to be determined based on the travel distance obtained by counting the output pulses of the sensor attached to the vehicle and the attitude angle obtained by the gyroscope attached to the vehicle. In a device that detects and thereby guides a vehicle, a plurality of marks of a certain length that can be optically detected along the direction of vehicle travel are laid down, and a detection signal of a detection device that detects the marks attached to the vehicle is transmitted. By providing a control circuit and a position determination circuit for correcting the count value of the sensor as a reference signal and the zero point drift of the gyroscope, an unmanned vehicle steering device such as a forklift that can always steer a desired course with high precision is obtained. Therefore, the present invention is extremely useful industrially.

[Brief explanation of the drawing]

Fig. 1 is an external side view of one embodiment of the present invention;
3 is a plan view of the inside of the building in this embodiment, and FIG. 4 is a control block diagram of this embodiment. 1... forklift, 2... running wheels, 3...
...Sensor, 4...Gyroscope, 5, 6...One-dimensional camera, 7...Front detector, 8...Load height detector, 9...Control device, 10...Mark, 11...
Branch line course, 11'... Main line course, 12... Loading platform, 13... Waiting station, 21... A/
D converter, 22... Adder, 23... Clock generator, 24... Signal processing device, 25... Comparison calculation device, 26... Master control unit,
27...Counter, 28...Correction calculation device, 29
...Position determination device, 30...Servo amplifier, 31
... Steering servo motor, 32 ... Transmission device, 33 ... Sensor control signal, 34 ...
Control signal for drive motor.

Claims (1)

[Claims] 1. The position of the vehicle on the travel route is detected from the travel distance obtained by counting the output pulses of a sensor attached to the vehicle, and the attitude angle command signal corresponding to the detected position is used to determine the position of the vehicle. In an unmanned vehicle steering device that steers a vehicle, a plurality of optical marks of a predetermined length are arranged on the ceiling directly above the traveling route along the traveling route, and are spaced from the vehicle in the vehicle traveling direction. at least two one-dimensional cameras that are arranged at a distance from each other and individually detect the optical marks; a position determination device that detects the position of the vehicle from the detection signals of the same-dimensional cameras and the travel distance; a control circuit that corrects an attitude angle based on an angular velocity signal of a gyroscope attached to the vehicle in response to a signal from the one-dimensional camera, and the detection signal from the one-dimensional camera is a reading count signal of the optical mark and , an unmanned vehicle steering system comprising a vehicle width direction deviation signal between the same optical mark and a same-dimensional camera.