JPH02280602A - Travel controller of unmanned vehicle - Google Patents

Abstract

PURPOSE:To prevent positional shift of the center of turning by performing speed change control of right and left motors such that there is no difference of traveling distance between right and left drive wheels. CONSTITUTION:Upon reception of a turning command signal from a travel command value 15, a CPU 12 provides rotary speed command values having the same magnitude in opposite directions to right and left motors 2, 3 through a pair of motor drive circuits 16, 17 in order to perform turning. Pulse signals corresponding to the traveling distance of drive wheels 4, 5 are fed from pulse encoders 18, 19 to the CPU 12. The CPU 12 calculates the difference of traveling distance between the drive wheels 4, 5 based on the pulse signals and controls the rotary speed of the motors 2, 3 such that the difference is eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a travel control device for an unmanned vehicle, and more particularly to a control device for turning travel.

[Prior Art] Conventionally, as an unmanned vehicle equipped with this type of travel control device, for example, as shown by the solid line in FIG. A left motor 32 and a right motor 33 for driving, and each of these motors 32 . ．． A four-wheeled unmanned vehicle is known which is equipped with a left drive wheel 3-4 and a right drive wheel 35 that are drive-coupled to a wheel 33, and casters 36 and 37 that are disposed on both sides of the drive wheels 34 and 35. It is being

This unmanned vehicle has a central processing unit (C) as shown in Figure 6.
PtJ) 38, continuous read only memory (ROM) 39 that stores control programs, readable and rewritable memory (RAM) 4 that temporarily stores calculation results of CPO 38, etc.
A travel control device consisting of 0 is equipped. Further, the CPU 38 is instructed to perform turning travel (
Various commands (such as turning command signals that instruct spin turns)
No. 8 is now input.

When the CPU 3B receives a turning command signal from the travel command section 41, the CPU 3B sends the rotation ratio and rotation speed of the left and right motors 32, 33 (in this case The rotation directions are exactly opposite to each other, and the rotation speed is the same).
It is determined based on the data stored in M39, and the rotation of each motor 32, 33 is controlled according to the determined command value. At this time, the number of rotations, that is, the rotational speed of each motor 32, 33 is detected by tacho generators 44, 45 provided corresponding to each motor 32, 33, and the CPU 38 outputs a detection signal of each tacho generator 44, 45. is input as feedback data for controlling the rotation of each motor 32, 33. That is, the CPU 3B controls the rotation of each motor 32, 33 so that the detected value of each tachogenerator 44, 45 becomes the determined multiple value, and also controls the rotation speed of each motor 32, 33. Control.

[Problems to be Solved by the Invention] However, in the conventional travel control device, the speeds of the left and right motors 32, 33 are controlled separately, so that the load applied to each drive wheel 34, 35 is unbalanced. In this case, there was a possibility that a difference would occur in the traveling distance of each drive wheel 3435.

For example, the deviation of the center of gravity of luggage loaded on an unmanned vehicle, the running resistance of casters 36, 37, unevenness of the road surface, or each motor 3
When the load imbalance occurs due to the difference in the rotational characteristics of wheels 2 and 33, as shown in FIG. Not only would there be a difference between them and the distance B, but there was also a risk that a large error E would occur between them and the regular running distance C.

Therefore, for example, when turning is performed when the load applied to the right drive wheel 35 is greater than that applied to the left drive wheel 34, as shown in FIG. As a result, the center of turning shifts from position po to position IPI, making it impossible to accurately turn at a fixed position.

This invention has been made in view of the above-mentioned circumstances, and its purpose is to provide a travel control device for an unmanned vehicle that can prevent the center of turning from shifting and can perform turning in a fixed position. It is about providing.

[Means for Solving the Problems] In order to achieve the above object, the present invention includes a pair of left and right drive wheels arranged at symmetrical positions with respect to the traveling direction on the underside of the vehicle body, and a pair of drive wheels on the left side thereof. Equipped with a left motor for rotationally driving the drive wheels and a right motor for rotationally driving the right side drive wheels, each motor is rotationally driven in opposite directions based on a turning command signal that instructs the vehicle to turn. In the driving control device for an unmanned vehicle that causes the vehicle to turn and travel through each drive wheel, the left driving distance detecting means detects the driving distance of the left driving wheel, and the right driving path M detects the driving distance of the right driving wheel. Detection means and each traveling route i! 1. A speed change control means is provided which determines the difference in travel distance of each drive wheel per predetermined travel time based on the detected value of the detection means, and performs speed change control of the rotation of each motor so that the difference is eliminated.

[Operation] Therefore, when the motors are driven to rotate in opposite directions to each other based on a turning command signal that instructs the vehicle to turn, and the vehicle is caused to turn through each drive wheel, the shift control means is controlled by the left travel distance detection means. Detection signals corresponding to the travel distance of each drive wheel are inputted from the right travel distance detection means and the right travel distance detection means, respectively. Then, the speed change control means determines the difference in travel distance of each drive wheel per predetermined travel time based on the detected value of each travel distance detection means, and controls the speed change of the rotation of each motor so that the difference becomes zero. .

As a result, the travel distance of each drive wheel during turning becomes equal, and the center of turning is maintained at a fixed position.

[Embodiment] Hereinafter, an embodiment in which the present invention is embodied in a four-wheeled unmanned vehicle will be described in detail with reference to FIGS. 1 to 3.

Fig. 2 shows the lower side of the unmanned vehicle, where a left motor 2 and a right motor 3 for driving are respectively disposed at symmetrical positions with respect to the traveling direction at the center of the lower side of the vehicle body 1. A left drive wheel 4 and a right drive wheel 5 are connected to drive wheels 2 and 3, respectively.

Furthermore, casters 67 are provided on both the front and rear sides of each of the drive wheels 4 and 5, respectively.

The electrical configuration of the driving control device installed in this unmanned vehicle will be explained according to FIG. 1. A microcomputer 11 as a speed change control means includes a CPU 12, a ROM 13 that stores a control program, and a RAM 14 that temporarily stores calculation results of the CPU 12. The CPU 12 executes processing operations for driving control according to the control program stored in the ROM 13.

In addition, CPIJ12 is a turning command signal that instructs turning movement,
Various command signals are inputted from an external travel command unit 15, such as a straight-ahead command signal that instructs to go straight, a right-turn command signal that instructs a right turn, and a left-turn command signal that instructs a left turn.

Furthermore, when the CPU 12 receives a turning command signal from the travel command section 15, the CPU 12 determines the rotation ratio and rotation speed of the left and right motors 2 and 3 (this In this case, the rotation directions are exactly opposite to each other and the rotation speed is the same).
The rotation of each motor 2.3 is controlled in accordance with the determined command value.

Each of the left and right motors 2.3 has a pair of left travel distance detection means and right travel distance detection means that output a number of pulse signals corresponding to the amount of rotation thereof, that is, the travel distance of each drive wheel 4, 5. Pulse encoders 18, 19 are connected. When the CPU 12 receives the turning command signal, the CPU 12 outputs the information from each pulse encoder 18, 19 to each driving wheel 4.
Input the number of pulse signals corresponding to the traveling distance of 5.

Based on the pulse signals from each pulse encoder 18, 19, the CPU 12 determines the difference in travel distance of each drive wheel 4, 5 per predetermined travel time, and determines the speed change value of each motor 2, 3 to eliminate the difference. Based on the calculated speed change value, a new command value for instructing the rotation speed of each motor 2.3 is determined, and the rotation speed of each motor 2.3 is controlled according to the command value. .

Further, the CPLI 12 time-differentiates the pulse signals from each pulse encoder 18 and 19 to determine the actual rotational speed of each drive wheel 4, 5, and uses the determined actual rotational speed to control the rotation of each motor 2, 3. input as feedback data for That is, the CPU 12 controls each motor 2 so that the actual rotational speed becomes the determined command value.
．． Control the rotation speed of 3.

Next, the operation of the travel control device configured as described above will be explained with reference to the graph of FIG. 3.

Now, when the loads on the left and right drive wheels 4 and 5 are unbalanced, when a turning command signal is output from the driving command unit 15, the unmanned vehicle starts turning.

In other words, the CPU 12 uses command values Nl and N for rotating the motors 2 and 3 in opposite directions at the same speed.
2 to each motor 2 via each motor drive circuit 16.17.
Output to 3. As a result, each of the driving wheels 4 and 5 starts running, and as shown in FIG.
It increases with the passage of time.

Then, due to the unbalance of 'fi applied to each drive wheel 4.5 and the town, for example, as shown at time t1 in FIG. 3, a difference α occurs in each traveling distance A, H (A>B),
12 eliminates the difference α (controls the rotational speed of each motor 2.3).

That is, the CPU 12 calculates the speed change value β of each motor 2.3 corresponding to the difference α between the travel paths fiA and fiB.

Then, the CPU 12 converts the calculated speed change value β into command values Nl and N2 for controlling the rotational speed of each motor 2, 3.
The rotational speed of each motor 2, 3 is controlled based on the calculation result. In other words, in this case, a new command value (Nl
-β), the left motor 2 is controlled +ff1l. In addition, a new command value (N2 +
The right motor 3 is controlled according to β).

As a result, as shown in FIG. 3, the distances A and B become approximately equal at time t2, which is a predetermined time after time tl, and at this point, the difference α between distances A and B is
converges to approximately zero and approaches the normal running distance C. As a result, displacement of the center of turning can be prevented, and the unmanned vehicle can be turned in a fixed position.

Therefore, the deviation of the center of gravity of the load loaded on the unmanned vehicle, the running resistance of the casters 6 and 7, the unevenness of the road surface, or the motors 2 and 3
In cases where the load on each drive wheel is unbalanced due to differences in the characteristics of the space.

Furthermore, since positional deviations during turning can be eliminated, the traveling accuracy of the unmanned vehicle can be further improved, and the position of the unmanned vehicle on the traveling course can be controlled more accurately.

Note that this invention is not limited to the above embodiments,
The present invention can be implemented as follows by changing a part of the structure as appropriate without departing from the spirit of the invention.

(1) In the above embodiment, the pulse encoders 18 and 19 are provided as the left travel distance detection means and the right travel distance detection means, and the travel distance of each drive wheel 4 and 5 is determined based on the signals from these pulse encoders 18 and 19. The configuration is configured to determine the difference α between A and B and the rotational speed of each drive wheel 4.5, but as shown in FIG. 4, the measuring wheels 25, Pulse encoders 27 and 28 for detecting the amount of rotation of each motor 26 may be provided, and tacho generators 29 and 30 for detecting the rotational speed of each motor 2 and 3 may be provided separately.

(2) In the above embodiment, each driving wheel 4, which is driven by each motor 2, 3 at a left-right symmetrical position in the lower center of the vehicle body 1,
5 and casters 6 and 7 provided on both the front and rear sides of the vehicle.As shown in FIG. The present invention may be embodied in a three-wheeled unmanned vehicle having drive wheels 4 and 5 driven by the vehicle body 1 and casters 7 provided at the lower rear of the vehicle body 1.

[Effects of the Invention] As detailed above, according to the present invention, it is possible to prevent the center position of the turning movement from shifting, and it is possible to perform accurate turning movement in a fixed position. This has the excellent effect of increasing the driving accuracy of unmanned vehicles.

[Brief explanation of drawings]

1 to 3 are drawings showing an embodiment embodying the present invention, in which FIG. 1 is a block diagram showing the electrical configuration of a traveling control device, and FIG. 2 is a diagram showing the traveling side of the device. FIG. 3 is a diagram showing the lower side of an unmanned vehicle to which the No. 11 device is applied, and is a graph illustrating changes over time in the travel distance of each drive wheel in the unmanned vehicle. 4 and 5 are drawings showing another embodiment embodying the present invention, in which FIG. 4 is a block diagram showing the electrical configuration of the travel control bag r, and FIG. 5 is a diagram showing the bottom of the unmanned vehicle. It is a figure showing a side. FIG. 6 is a block diagram showing the electrical configuration of a conventional travel control device, FIG. 7 is a diagram illustrating turning travel of an unmanned vehicle to which the travel control device is applied, and FIG. 8 is a diagram showing each drive in the unmanned vehicle. It is a graph explaining the change over time in the traveling distance of a wheel. In the figure, 1 is the vehicle body, 2 is the left motor, 3 is the right motor, and 4
11 is a microcomputer as a speed change control means, 18.19 is a pulse encoder as a left and right travel distance detection means, 2 is a left drive wheel, -5 is a right drive wheel,
7.28 is the same <pulse encoders as left and right travel distance detection means, A is the left travel distance, B is the right travel distance, and α is the difference in travel distance.

Claims (1)

[Scope of Claims] 1. A pair of left and right drive wheels disposed on the lower side of the vehicle body in symmetrical positions with respect to the traveling direction, a left motor for rotationally driving the left drive wheel, and the right drive. and a right motor for rotationally driving the wheels, and based on a turning command signal instructing the vehicle to turn, each of the motors is rotationally driven in opposite directions to each other to cause the vehicle to turn through the respective drive wheels. A travel control device for an unmanned vehicle, comprising: a left travel distance detection means for detecting a travel distance of the left drive wheel; a right travel distance detection means for detecting a travel distance of the right drive wheel; and each of the travel distance detection means. A driving control device for an unmanned vehicle, comprising: a speed change control means that determines the difference in travel distance of each of the drive wheels per predetermined travel time based on the detected value, and controls the speed of the rotation of each of the motors so that the difference is eliminated. .