JPH0820900B2 - Unmanned vehicle running control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a two-wheel drive type unmanned vehicle traveling control device, and more particularly to a rotation angle control device during spin turn (in-situ rotation).

B. Summary of the Invention The present invention utilizes the pick-up coil used for traveling control during the spin turn of a two-wheel drive type unmanned vehicle, and the peak value of the voltage detected by each of the left and right pick-up coils is a relative peak. After detecting as a value, the difference between the two is taken, and when this difference voltage exceeds a set value (eg OV), it is judged as the end of the turn and the drive motor is stopped. This is to obtain a highly accurate control device that is not affected by changes in current.

C. Conventional technology Among unmanned guided vehicles, the two-wheel drive type unmanned vehicle that is driven by independent left and right drive motors is used in various fields because it has a spin-turn function and is very convenient. .

By the way, there are various methods for performing a spin turn, but as a general method, rotary encoders are attached to both wheels of the trolley, and the encoder detects the rotational speed of both wheels to detect the attitude angle of the spin turn. There is.

D. Problems to be Solved by the Invention The conventional type using the rotary encoder is
Not only is the encoder expensive, but the attitude angle accuracy of the vehicle at the end of the spin turn is poor, which may cause the vehicle to go off the course. This point will be described below.

In Fig. 7 (a), the unmanned vehicle AGV centered on the guide wire 1 turns 180 ° in the direction of the arrow at the position of the line a (left when the pick-up coils 2 and 3 are the traveling directions). Consider the case where the unmanned vehicle AGV that makes a turn has a rectangular shape indicated by a solid line and the square shape indicated by a dotted line. Assuming that the encoders that detect the rotational speeds of the tires (wheels) 4 and 5 have the same accuracy, the pick-up coil 3'in the AGV of the dotted-line square shape as shown in FIG. By the spin turn, the induction wire 1 is turned over to the position where it crosses the induction wire 1 with the coils 2 ', 3', but in the case of the rectangular unmanned vehicle AGV shown by the solid line, the coil 3 is The course is in a state where the guide line 1 is not exceeded. This means that even if the encoder detects the rotation speed of the tires 4 and 5, and controls the completion of spin turn when the rotation speed reaches a predetermined rotation speed, the center position of the tires 4 and 5 and the pick-up coil This means that the attitude angle of the car after a spin turn changes depending on the distance between 2 and 3, making adjustments for stability of the attitude difficult.

The present invention has been made in view of these points, and an object of the present invention is to provide an apparatus that enables inexpensive and highly accurate spin turn control.

E. Means for Solving Problems The present invention uses the left and right pick-up coils used for running, and during spin turns, the detected voltage of the pick-up coil in the anti-spin turn direction is sampled and stored, and the stored value And compare the value sampled this time,
The voltage of the difference becomes equal to or lower than a predetermined level (for example, OV) and the first comparison means for comparing whether or not the detection voltage exceeds the peak value and the comparison result by this comparison means exceed the peak point of the detection voltage. When it is determined that the detected voltage of the spin-up side pick-up coil is sampled and stored, the stored value is compared with the value sampled this time, and the difference falls below a predetermined level (for example, OV), and the detected voltage peaks. The difference between the second comparing means for comparing whether or not the value is exceeded and each detected voltage after the time when the peak value detected by each of these comparing means is exceeded is detected. For example, the difference signal calculating means outputs a stop signal to the drive motor when it becomes OV).

F. Operation With this configuration, the left and right pick-up coils, which are located across the induction wire, sample the detection voltage of the coil when the coil on the opposite turn side first intersects with the induction wire during spin turn. By comparison, when the current value is smaller than the previous value and becomes OV or less, it is determined that the pick-up coil on the anti-turn side has crossed the guide wire. On the condition that the coil on the opposite turn side has crossed the induction wire, it is similarly detected that the coil on the turn side has crossed the induction wire. Then, the difference between the two detection voltages after the time when it is determined that each coil has crossed the induction wire is determined, and when the difference is equal to or greater than the set value, it is determined that the vehicle attitude angle is correct and the drive motor is stopped. To do.

G. Example An example of the present invention will be described in detail below with reference to the drawings.

In FIG. 1, 2 and 3 are pick-up coils, and these coils 2 and 3 are left and right on the head side in the traveling direction of the AGV, respectively.
Moreover, it is arranged at a position facing the floor surface. Reference numerals 6 and 7 denote amplifiers, and reference numerals 8 and 9 denote analog-to-digital converters. The converters 8 and 9 sample input analog signals at arbitrary time intervals and convert them into digital signals. 10,11
Is a memory and stores the value of one sampling. Reference numeral 12 denotes a first comparing means, which calculates the difference between the current sampling value and the previous sampling value stored in the memory 10, and the difference value is equal to or lower than a predetermined level OV. And output if OV or less,
Reference numeral 13 is a second comparison means, and this comparison means 13 also has the same function as the first comparison means 12. Reference numeral 14 is a difference signal calculating means, which obtains the difference between the difference signals after being less than or equal to OV input from the comparing means 12 and 13, and outputs a stop signal for the drive motor when the signal is greater than or equal to OV. To do.

An unmanned vehicle AGV having a control device configured as described above
As shown in FIG. 2, the pick-up coils 2 and 3 are positioned across the guide wire 1, and the coils 2 and 3 travel while detecting the magnetic field generated from the guide wire 1.

FIG. 3 shows the relationship between the voltage output by the pick-up coil 2 or 3 detected by the position of the induction wire 1 and the output voltage. When the coil crosses the induction wire 1 and moves rightward or leftward, it crosses the magnetic field. By doing so, the AC half-wave voltage is detected.

In such a case, the operation when the spin turn command is output to the drive motor (not shown) will be described with reference to FIGS.

When the unmanned vehicle AGV receives the left spin turn command in the state of FIG. 4 (A) and becomes in the posture of (B), the detection voltage of the right pick-up coil 2 on the anti-spin turn side exceeds the induction wire 1. As a result, as shown by the voltage waveform R in FIG. 5, (A) → (B) increases, but the detected voltage of the left pick-up coil 3 becomes zero.

Next, when the unmanned vehicle AGV changes from (C) to (D),
This time, when the coil 3 on the left side, which is the turn side, produces an output as shown by the waveform L in FIG. 5, and when the attitude of the vehicle becomes (E),
Each of the coils 2 and 3 is in a state of generating a certain positive signal.

Therefore, the voltages of the waveforms R and L are stored, and when the voltage difference between the two becomes 0, it can be detected as the end of the spin turn. However, the detection voltage of the pick-up coils 2 and 3 and the voltage difference between the two are: Since it changes due to changes in the exciting current of the induction wire 1 and changes in the distance between the induction wire 1 and the coils 2 and 3,
There may be cases where a normal turn can be made at one place but not at the next. Therefore, in the present invention, as a method of detecting the peak value of the voltage, not the absolute voltage but the relative value is detected and judged.

That is, FIG. 6 shows a flow chart at the time of spin turn. Step S ₁ issues a left spin turn command to the motors of the drive wheels 4 and 5, and step S ₂ outputs the analog-digital converter. The detected voltage of the right coil 2 sampled at 8 is stored in the memory 10. The detection voltage is sampled at certain time intervals, and the step S ₃
Then, the difference ΔV _R (= V _Rn −V) between the current sampling value V _Rn and the previous sampling value V _Rn-1 stored in the memory 10
_Rn-1) and determined, step S ₄ in the difference value [Delta] V _R is equal to or greater than 0. If it is greater than 0, it means that the detected voltage is in the rising direction (the coil has not yet intersected with the induction wire). Returning to step S ₂ , the difference from the next sampling value is obtained, and this difference value ΔV Comparison is judged until _R becomes less than 0. When ΔV _R ≦ 0, it is judged that the detected voltage has exceeded the peak value (peak value in FIG. 5R), and the left coil 3
Outputs an instruction to start sampling of the detection voltage of.
It was but started connexion sampled stores that value in the memory 11 (step S _5). The difference ΔV seek _{L (= V Ln -V Ln-} 1) of the previous sampling value V _Ln-1 stored in the step S ₆ the current sampled value V _Ln and memory 11, step S
_{At 7} , it is judged whether or not the difference value ΔV _L is larger than 0. If it is larger than 0, the process returns to step S ₅ , the same calculation is performed with the next sampling value, and the process is repeated until ΔV _L becomes smaller than 0. [Delta] V _L ≦ 0 and the detected voltage when there was summer, it is determined that exceeds the peak value, obtain the difference _{ΔV D (= V R -V L} ) of the detection voltage after exceeding the peak value at step S _8, step S _{At 9,} the comparison of ΔV _D ≦ 0 is made. This comparison is repeated until ΔV _D becomes larger than 0, and when it becomes large, it is judged that the unmanned vehicle AGV has come to the guideline 1 immediately and the step is judged.
Spin turn is completed by outputting a stop command of the drive motor at S _10.

In the above embodiment, the left spin turn has been described, but the same applies to the right spin turn.
Also, I explained that the turn angle is 180 °,
When the guide wires are crossed in a cross shape, the detection control can be performed in the same manner even with a 90 ° turn angle or the like.

H. Effects of the Invention According to the present invention as described above, since the pick-up coil is used for controlling the rotation angle at the time of spin turn, it is not necessary to use an expensive rotary encoder, so that the cost is low, and any vehicle Accurate spin turns are possible even for long objects. Further, according to the present invention, the detection of the peak value output when the left and right pick-up coils cross the induction wire is relatively detected. Therefore, the change in the exciting current of the induction wire, the steel frame, the duct, the iron plate, etc. Even if the magnetic field changes due to the ambient conditions due to the presence of, spin turns can be accurately performed.

[Brief description of drawings]

FIG. 1 is a circuit configuration diagram showing an embodiment of the present invention, FIG. 2 is a state diagram of an unmanned vehicle for explanation, FIG. 3 is a positional relationship diagram between a pick-up coil detection voltage and an induction wire, and FIG. FIG. 5 is an explanatory view of the posture of the vehicle during a spin turn, FIG. 5 is a voltage waveform diagram during a spin turn, FIG. 6 is a flow chart of the same as above, and FIG. 7 is an explanatory view during a conventional spin turn. 1 …… Induction line, 2,3 …… Pickup coil, 4,5 …… Drive wheel, 8,9 …… Analog-digital converter, 10,11 ……
Memories 12, 13, ... First and second comparing means, 14 ... Differential signal calculating means.

Claims (1)

[Claims] 1. A spin turn control device for a two-wheel independent drive type unmanned vehicle, which travels while detecting magnetism from a guide wire with left and right pickup coils, wherein the left and right pickup coils have an anti-spin turn direction. Of the detection voltage of the pickup coil of the first sampling circuit, and stores it, calculates the difference between the current sampling value and the previous sampling value, and compares the difference value with a predetermined level. Based on the result, the detected voltage of the pickup coil in the spin turn direction after the peak point of the detected voltage is sampled and stored, the difference between the current sampled value and the previous sampled value is calculated, and the difference value and the predetermined value are calculated. Second comparison operation means for comparing with the level, and detection voltage after the time when the peak point detected by the first comparison operation means is exceeded And a means for subtracting the detected voltage after the peak point detected by the second comparison operation means, and a spin when the value obtained by this subtraction means is equal to or greater than the set value. An unmanned vehicle running control device comprising: a difference signal calculating means for outputting a turn stop signal.