JPH0277807A - Travel controller for traveling body - Google Patents

Abstract

PURPOSE:To prevent trouble such as snaking, travel unstableness, and derailment due to a secular change by correcting an offset automatically every time the travel body stops at a target station. CONSTITUTION:A difference between detection signal obtained from a couple of front coils 4L and 4R and a couple of rear coils 4L and 4R after the traveling body is stopped in front of a load receiving table and centering mechanisms 3L and 3R are put in operation is inputted as a deviation signal from a deviation signal detecting circuit 140. Then the value of a deviation signal offset is subtracted from the deviation signal to calculate their difference as a speed correcting value. Lastly, the value obtained by subtracting the speed correcting valve from the target traveling speed of the traveling body is regarded as the target speed of a right driving wheel 2R and the value obtained by adding the speed correcting value is outputted as the target speed of a left driving wheel 2L to a servo amplifier 150. Consequently, the traveling speed can be made to travel at the target speed along a guide line and every time the traveling body stops in front of the load receiving table and the centering mechanisms operate, the offset value is corrected automatically.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a travel control device for a traveling object, such as a traveling robot or an automatic guided vehicle used in an unmanned factory, which controls the stopping position of the traveling object.

In an unmanned factory, transporting, picking up, and handing over loads such as workpieces between automated warehouses and cell receiving tables is carried out by moving objects such as moving robots and automatic guided vehicles. refers to a device for controlling the traveling of this traveling body.

[Conventional technology]

These traveling bodies move, for example, while being guided by a guide wire buried directly below the traveling route. That is, the magnetic field generated from the guide wire through which current is passed is detected by at least one pair of pickup coils or the like installed on the left and right sides of the traveling body with respect to the traveling direction, and it is determined whether or not the vehicle is traveling correctly. There is. If the traveling object deviates from the traveling route, the rotation of the left and right drive wheels is controlled to cancel the deviation.

More specifically, signals from at least one pair of left and right pickup coils are introduced into the positive input and negative input of a differential amplifier, and the difference signal is amplified at a predetermined amplification factor, or a predetermined number is added to the signal. The control amount is obtained by multiplying the control amount, and the signals obtained by adding and subtracting this control amount from the speed target value are used as the target speeds of the left and right wheels, respectively.

In this case, if there is a certain amount of offset in the output of the differential amplifier, it will cause disturbances in the control system, but conventionally, calibration is performed before operation, and the induced deviation is corrected by removing the offset. Met.

[Problem to be solved by the invention]

If corrections were made only once before operation, the offset and gain of the control system, including the sensor, would drift due to changes over time, resulting in changes in dynamic characteristics, which could cause problems such as meandering, unstable running, and derailment. .

Even if it were to be readjusted periodically, it would have to be done by a professional engineer, and it would be a cumbersome task.

Therefore, an object of the present invention is to provide a travel control device that can prevent problems such as meandering, unstable running, and derailment caused by aging without requiring any troublesome adjustment work.

[Means to solve the problem]

FIG. 1 is a diagram showing the principle of the present invention. The travel control device for a traveling object according to the present invention allows a traveling object 10 to travel while being guided along a guide line 103 at a predetermined speed 52 including low speed and high speed, and is configured to prevent a deviation of the traveling object from the guide line 103. At least one deviation detection means 14 detects and outputs the deviation signal 70, and the difference between the deviation signal offset 50 and the predetermined speed 52 determines the target speeds 72, 74 of the left and right drive wheels 20, 22 of the traveling body 10, respectively. a control calculation means 16 that calculates and outputs the same; a wheel speed control means 18 that controls the speeds of the left and right drive wheels 20, 22 according to the target speeds 72, 74; and a centering mechanism 24 that mechanically corrects the stop position after the vehicle has stopped, and the deviation signal 70 is output within a period after the centering mechanism 24 is activated and before the traveling body 10 starts traveling again. The present invention is characterized by comprising an averaging means 32 for averaging and outputting values, and an offset correcting means 30 for setting the output of the averaging means 32 as a deviation signal offset 50.

[For production]

Since the offset is automatically corrected each time the traveling body 10 stops at the target station, control problems can be prevented without complicated operations. Further, by averaging a predetermined number of times, the influence of high frequency noise can be removed.

〔Example〕

An embodiment in which the present invention is applied to an electromagnetic induction traveling robot system that loads and unloads cargo by moving between a plurality of cargo receiving tables will be described below.

First, the system configuration of this example will be explained.
In FIG. 2, reference numeral 100 denotes a VTC (Vehicle Traffic Controller) that controls the traveling of the traveling robot 1.
VCU (Vehicle C)
The line driver 102 is driven in response to a command from the ontroller>101, and the traveling robot 1 is moved along the guide line 10.
The vehicle is controlled to travel along the lines 3 and 3. In addition, the guide wire 1
On the path 03, magnets for confirming the position of the traveling robot 1 are provided at positions corresponding to the target stations, that is, approximately at the center of each of the receiving tables 104, 105, 106, and 107 of each cell. Loading platform 104,
Reference numerals 105 , 106 , and 107 are load receiving stands on which the travel port bot 1 receives, transfers, or receives loads such as workpieces.

Next, the configuration of the traveling robot 1 will be explained.

FIG. 3 is a diagram of the traveling robot 1 viewed from the bottom (back side).

As shown in FIG. 3, the traveling robot 1 has drive wheels 2L and 2R driven by different servo motors.
, and coils 4 L and 4 R for detecting the induced magnetic field generated in the guiding wire 103 are located at the front and rear portions of the approximately central portion.
Furthermore, on the outside thereof, there is a wire cross sensor 5L that detects the point where the guide wire 103 intersects.

Magnetic sensors 6 L and 6 R are provided for detecting magnets provided along the paths of the guide wire 103 and the guide wire 103 . Note that 7 is a receiving antenna that receives signals from VTCloo, and 8 is a receiving antenna for receiving signals from VTCloo.
It is a transmitting antenna that transmits signals to.

There are centering mechanisms 3L and 3R at the four corners of the running robot.
is provided, and the traveling robot 1 is placed on the loading platform 104-1.
After stopping correctly at a predetermined position in front of any one of 07 (Fig. 2), the stop position is mechanically corrected by engaging with the receiver that is projected downward and provided on the road surface. do.

Next, a control device for the traveling robot 1 will be explained.

As shown in FIG. 4, the control device for the traveling robot 1 includes a microprocessor (hereinafter referred to as CPC) 900 that controls the traveling robot 1, and a control program etc. is written to the CPU 900 via a bus 110. daROM
and a memory 200 configured with a RAM that stores various setting values; a receiving circuit 120 that receives wireless signals from VTCloo via the receiving antenna 7; and a transmitting circuit 13 that transmits wireless signals to the VTCloo via the transmitting antenna 8.
0. Coil 4 that detects the induced magnetic field generated in the guiding wire 103
The difference between the detection values picked up by L and 4R is amplified by a differential amplifier, A/D converted, and sent to the CPU.
Deviation signal detection circuit 140 input to 900, drive wheel 2
A servo motor ML that drives L, 2R and a servo amplifier 150 that drives and controls MR are connected, and further, a magnetic sensor 6L that detects a magnet provided along the path of the guide wire 103 via an input/output circuit 190. , 6R, centering mechanism 3L, and wire cross sensor 5L that detects when the 3R1 guide wires 103 intersect.

A brake device 180 (not shown) is connected to stop the rotation of the drive wheels 2L and 2R of the 5R1 traveling robots 1-1.

Among the operations of the control device having the above configuration, travel control processing including automatic offset correction processing, which is a feature of the present invention, will be explained based on the processing flowchart of FIG. 5.

First, immediately after the centering cylinder is stored, that is, after stopping in front of one of the cargo receiving platforms 104 to 107 and activating the centering mechanism, it is not immediately before starting to move to the target of the clothes again (step a). ), the deviation signal detection circuit 140 generates a deviation signal ε1. Input as ε2 (step g). If it is after the operating value of the centering mechanism, ε1. In step b), the operation of inputting the value of ε2 is repeated a predetermined number of times, for example, 10 times, and the average value of each is 1. τ2 is calculated in step C), and its value is set as the value of the deviation signal offset ε1', 62' and the value of the deviation signal ε1. Substitute the value of ε2 (step d)
. Next, it joins the processing after step g, and the deviation signal ε0. ε
2 to deviation signal offset ε! '.

The values of ε2' are each subtracted, each parameter is multiplied by 2, and the difference between the two is taken as a speed correction value Δ■ (step e). The reason why the difference is taken as the speed correction value is that if the signal from 4L is strong among the signals from the pair of coils 4L and 4R in front, the vehicle will not be able to return directly above the guide line after turning to the left. This is because if the signal from 4L among the signals from the pair of coils 4L and 4R at the rear is strong, on the other hand, if the vehicle turns to the right, it can return directly above the guide line. Finally, the value obtained by subtracting 8■ from the target speed of the traveling body is set as the target speed of the right drive wheel 2R, and the value obtained by adding ΔV is output to the servo amplifier 150 as the target speed of the left drive wheel 2L (step f). .

By repeating the above process, the traveling body can be made to travel at the target speed along the guide line 103, and each time the traveling body stops in front of the loading platform 104 to 107 and the centering mechanism is activated, the offset value is adjusted. Automatic correction is performed.

〔Effect of the invention〕

As described above, according to the present invention, the running control device for a running body is capable of automatically correcting the offset, and prevents problems such as meandering, unstable running, and derailment caused by aging. is provided.

[Brief explanation of the drawing]

FIG. 1 is a diagram of the principle of the present invention, FIG. 2 is a system configuration diagram of an embodiment of the present invention, FIG. 3 is a view of the traveling robot 1 of FIG. A block diagram of the control device of the traveling robot 1, and FIG. 5 is a flowchart of the traveling control process. In the figure, 10... Running body, 103... Guide wire, 24...
...Centering mechanism.

Claims (1)

[Claims] 1. The traveling body (10) is moved along the guide line (1) at a predetermined speed (52).
03), wherein the traveling control device causes the traveling body (10) to travel while guiding along the guiding line (103), and at least one deviation detection device that detects a deviation of the traveling body (10) from the guiding line (103) and outputs the detected deviation as a deviation signal (70). means (14) and the deviation signal (70
) and the deviation signal offset (50) and the predetermined speed (52).
control calculation means (16) for calculating and outputting target speeds (72, 74) for each of the target speeds (72, 74);
2, 74), the left and right drive wheels (20, 2
2), and a centering mechanism (24) that mechanically corrects the stop position after the traveling body (10) reaches the target station and stops.
), the values of the deviation signal (70) are averaged within a period after the centering mechanism (24) is activated and before the traveling body (10) starts traveling again. averaging means (32
), and offset correction means (30) for setting the output of the averaging means (32) as the deviation signal offset (50).
) A traveling control device for a traveling body, characterized in that the device comprises: