JPS61168022A - Controller for automatic carrier car - Google Patents

Abstract

PURPOSE:To easily operate and determine the manipulated variable of an automatic carrier car, by taking the mean value of signals of plurally arrayed optical sensors by giving prescribed weights to the signals and calculating the positional error of the carrier car to its moving path, and then, controlling the carrier car so that the steering angle can become the minimum. CONSTITUTION:Output signals of optical sensors 14-18 become '1' or '0' depending upon whether a metallic tape 19 is detected or not in their visual fields. Weights of '-2', '-1', '0', '1', and '2' are given to the signal of each sensor in their arrayed order from left and the signals are converted into prescribed logical levels at an inter face 20, and then, the mean value A1 of the sensor unit 13 at the front section of a carrier car and the mean value A2 of the sensor unit 12 at the rear section of the carrier car are found by means of a mean value circuit 23. Both the mean values A1 and A2 represent the positional deviation of the carrier car 1 to the metallic tape 19 and take values of -1.5-1.5. Then the manipulated variable Qc [Qc=K1(A1+A2)+ K2(A1-A2)] is found by means of an arithmetic circuit 21. The K1 and K2 of the formula in the bracket are gain constants determined in accordance with a control rule. The manipulated variable Qc is converted into a steering angle command by means of a DA converter 22 and controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a steering controller 2 for an automatic guided vehicle.

[Prior art]

An example of an automatic guided vehicle to be controlled is shown in FIGS. 1 and 2. 1 is a truck, 2 and 3 are drive wheels for moving the truck 1, 4 and 5 are slave shafts, and 6 to 9 are drive wheels 2.3, slave 4,
10.11 is a motor for rotating the drive wheels 2.3 to make the trolley 1 travel; 12.13 is a sensor unit for detecting sources from the moving path; Optical sensor 1 consisting of a transistor
4.15.16.17.18 are arranged in a line.

A metal tape 19 is provided on the road surface along which the trolley 1 moves, and reflects light from a suitable light source to indicate the path of movement.

There is a controller shown in FIG. 3 that controls such an automatic guided vehicle. 20 is a sensor unit 12.
Twin interface to read 13 sensor signals,
Reference numeral 21 denotes an arithmetic circuit that calculates the manipulated variable by the arithmetic operation shown in FIG. 3 based on the signal from the interface 20, and is composed of, for example, a computer. 22 is a digital/analog (D/A') converter that converts the manipulated variable output from the computer 21 into an analog signal.

Next, the operation will be explained. Optical sensor 14°T 5
, 16 , 17 , 18 have metal arps 19 within their field of view.
If there is, the reflected light is received and the output signal is set to '1', otherwise it is set to '0'. After the voltage level of this output signal is converted by the interface 20, the output signal is sent to the arithmetic circuit 2.
1 is input. The arithmetic circuit 21 executes the process shown in FIG. 4 to determine the manipulated variable θC, and
~22d gives an analog steering angle command θ
Convert a to θd. Steering angle command θa~θ
The motors 6 to 9 are controlled by dK, and the drive wheels 2 and 3 are inspected for defects 4.
and determine the angle of 5. Thereby, the automatic transport vehicle, that is, the trolley 1 is controlled to travel along the metal tape 19.

The calculation algorithm in the calculation circuit 21 is shown in a chart 70 in FIG. Arithmetic circuit 21 is sensor unit 12.1
The sensor signals of each of the optical sensors 14, 15, 16, 17, and 18 of 3 are read as 5-bit binary sensor data with the most significant bit of the optical sensor 14 and prepared in advance in a memory (not shown). The operation amount θC is read out by referring to a table of two-dimensional steering angle commands. The values stored in this table are calculated offline in advance according to the control law.

Conventional controllers were configured as described above and had drawbacks such as the need to recalculate the degree command.

[Summary of the invention]

This invention was made in order to eliminate the drawbacks of the conventional ones as described above, and it weights the signals of each arrayed optical sensor with a predetermined weight, and uses the average value of these to calculate the position error of the cart with respect to the moving path. An object of the present invention is to provide an automatic guided vehicle controller that can simplify the device by calculating the position error and controlling the trolley motor so that this position error is minimized as a steering angle command.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. The automated guided vehicle to be controlled is shown in FIG. FIG. 5 shows a controller that controls this controlled object. In the figure, the same reference numerals as those in the figures described above indicate the same parts, and 23 is an averaging circuit that calculates the average value between the sensor signals of the sensor units 12 and 13. Here, at least two sensor signals of the optical sensor 141T are "1".

Next, the operation will be explained. Each sensor signal output from the optical sensors 14 to 18 is "1" if the metal tape 19 is detected within its field of view, and *oN if it is not detected.
It has already been explained that, as shown in FIG. 7, for each sensor signal, -2, -
Weightings of 1, 0, 1, 2 are given. The possible combinations of sensor signals are shown in the table below.

The table interface 20 inputs such a sensor signal, converts its voltage level to a predetermined logic level, and inputs the converted signal to the averaging circuit 23. As shown in FIG. 6, the averaging circuit 23 calculates the average value A1 of the sensor signal of the sensor unit 12 in step S1, calculates the average value A2 of the sensor signal of the sensor unit 13 in step S2, and calculates the average value A2 of the sensor signal of the sensor unit 13 in step S2. is input to the arithmetic circuit 21. Here, V! is the value assigned to the i-th optical sensor, i = 1
~5 is a sensor unit 12 at the front of the truck, i = 6 to 10 is a sensor unit 13 at the rear of the truck
, nl is the number of optical sensors that are ``l'' in the sensor unit 12, and n2 is the number of optical sensors that are 1'' in the sensor unit 13 at the rear of the truck.

As is clear from the table, when the trolley 1 is in the normal position, the average value Al and A2 of the averaging circuit 23 is -1.5 to 1.
．． It becomes 5. That is, the average value A1. of the averaging circuit 23. A
2 represents the positional deviation of the cart 1 with respect to the metal tape 19.

The arithmetic circuit 21 calculates θ as shown in step 83 in FIG. = kl(A1+A2)+k2(A1-A
The operation amount θ is determined by the calculation in 2). seek. Here, k engineering.

k2 is a gain constant determined by the control law.

The obtained manipulated variable θ. is input to the D/A converters 22a to 22d, converted into analog, and converted into a steering angle command 0.
3 to θd, and the operation amount θ. The motors 6 to 9 are driven with the polarity such that . Thereby, the trolley 1 is controlled to run along the metal tape 19.

In the above embodiment, the steering motor command was obtained by digital calculation, but this calculation follows the algorithm shown in Fig. 6, and the operation amount is determined using the average value of each signal. This structure has the advantage that the manipulated variable can be easily calculated and the control gain can be easily changed.

[Brief explanation of the drawing]

Figure 1 shows the bottom structure of the truck, Figure 2 shows the arrangement of optical sensors, Figure 3 is a block diagram of a conventional controller, and Figure 4 shows the calculation algorithm of the controller shown in Figure 3. FIG. 5 is a block diagram of a controller according to an embodiment of the present invention, FIG. 6 is a flowchart showing the calculation algorithm of the controller shown in FIG. 4, and FIG. 7 is a diagram showing weighting of the optical sensor according to the present invention. be. DESCRIPTION OF SYMBOLS 1... Trolley, 14.15.16.17.18... Optical sensor, 20... Interface, 21... Arithmetic circuit, 22a-22d... D/A converter. In addition, in the figures, the same reference numerals indicate the same parts. Patent applicant: Director of the Agency of Industrial Science and Technology Tatsu Todoroki Figure 1 Figure 2

Claims (1)

[Claims] The wheels are provided with a plurality of sensors arranged in a direction intersecting the guide members so as to optically detect the guide members provided along the running path, and the wheels run according to the sensor signals of the respective sensors. In an automatic guided vehicle controller that controls the automatic guided vehicle to travel along the travel path by controlling the angle, an averaging circuit that weights the sensor signals of the sensors to obtain an arithmetic average; An automatic guided vehicle controller comprising: a circuit that controls the traveling angle so that the average becomes a predetermined value.