JP2946778B2 - Travel control device for hydraulically driven vehicle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a travel control device for a hydraulically driven vehicle used for an asphalt finisher, a slope maintenance vehicle, an automatic guided vehicle, an agricultural work machine, and the like.

[0002]

2. Description of the Related Art In general, a hydraulically driven vehicle such as an asphalt finisher forms a pair of hydraulic transmissions by connecting a pair of left and right hydraulic pumps and a pair of hydraulic motors in a closed circuit in the same manner. Are driven independently.

As a traveling control device for the hydraulically driven vehicle, the following has been proposed in Japanese Utility Model Application No. 1-115751. The content of the proposal is shown in FIG.
As shown in the figure, a pair of hydraulic transmissions 3L in which variable displacement hydraulic pumps 1L and 1R having swash plates 9L and 9R as variable control elements and constant displacement hydraulic motors 2L and 2R are connected in a closed circuit. , 3R, and the inclination angle control cylinders 4L, 4L, of the swash plates 9L, 9R for controlling the capacity of the hydraulic pumps 1L, 1R.
4R, the engine 5 for driving the hydraulic pumps 1L, 1R, and the hydraulic motor 2
Left and right traveling devices 6L, 6R rotated via L, 2R
And a charge pump 7 attached to the hydraulic pump 1R side
And control valve devices 8L and 8R connected to the output side of the charge pump 7 and configured to control the swash plate tilt angle control cylinders 4L and 4R, and an optical fiber gyro for detecting the turning angular velocity of the hydraulically driven vehicle. And an arithmetic unit E for controlling the control valve devices 8L and 8R based on the turning angular velocity signal from the angular velocity sensor S. The control valve devices 8L and 8R are controlled by a deviation signal from the arithmetic unit E based on the turning angular velocity signal from the angular velocity sensor S, and the control is performed via the swash plate inclination angle control cylinders 4L and 4R. By changing the tilt angles of the swash plates 9L and 9R provided on the hydraulic pumps 1L and 1R, and controlling the amount of oil from the hydraulic pumps 1L and 1R to the hydraulic motors 2L and 2R, the travel is achieved. The rotation speeds of the devices 6L and 6R are individually controlled to correct the directions, and the vehicle is caused to travel straight in the set straight traveling direction.

[0004]

However, in the above-described traveling control device, since only the angular velocity of the vehicle is detected and controlled by the sensor S, the direction can be corrected when the vehicle turns. It is not possible to ensure the straightness of the entire traveling locus with respect to the target. That is, as shown in FIG.
For example, when the hydraulically driven vehicle travels from the starting point A to the target position B, a difference occurs between the rotational speeds of the left and right traveling devices 6L and 6R due to disturbance or the like due to, for example, unevenness of the road surface or wetness. Each time the hydraulically driven vehicle deviates outward at a certain traveling position a1... With respect to a linear target traveling locus C connecting the starting point A and the target position B, Each of the traveling devices 6L, 6R is a deviation signal from the arithmetic unit E based on the angular velocity sensor S at the position of a1,.
By controlling to increase the rotation speed of one of the
Although the traveling direction of the hydraulically driven vehicle can be corrected to the target straight traveling direction, the deviation generated between the target traveling trajectory C and the actual traveling trajectory D of the hydraulically driven vehicle due to the direction correction can be adjusted. Cannot be modified. For this reason, if such a direction correction is repeatedly performed, a large deviation value ΔT remains between the target traveling trajectory C and the actual traveling trajectory D of the hydraulically driven vehicle, and the hydraulically driven vehicle reaches the target position B. It could not be reached exactly. In other words, the vehicle could only travel straight along the straight target travel locus C.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to not only ensure the straightness of a hydraulically driven vehicle, but also to correct the deviation generated at the time of correcting the direction. It is an object of the present invention to provide a travel control device capable of accurately traveling a hydraulically driven vehicle from a starting point to a target position along an arbitrary target travel locus.

[0006]

In order to achieve the above object, the present invention provides a hydraulic pump 1L, 1R and a hydraulic motor 2L.
L, 2R and a pair of hydraulic transmissions 3 connected in a closed circuit
L, 3R, and a hydraulic drive vehicle that independently drives the left and right traveling devices 6L, 6R by the hydraulic motors 2L, 2R, respectively.
3R, a displacement control element 9 provided in at least one of the hydraulic pumps 1L, 1R and the hydraulic motors 2L, 2R.
L, 9R, and a control valve device 8L, 8R, and an angular velocity sensor 10 for detecting a turning angular velocity of the hydraulically driven vehicle.
And left and right speed detection sensors 11L and 11R for detecting the speeds of the left and right traveling devices 6L and 6R, a turning angular speed signal from the angular speed detection sensor 10 and a vehicle running speed signal from the left and right speed detection sensors 11L and 11R. Calculating means 14 for outputting a position signal at the X coordinate and Y coordinate, a target position commanding means 15 for outputting a position command signal based on a preset target travel locus, and the position signal and the target position command. A comparison means 16 for calculating a signal and outputting a deviation value of the position, and an output means 17 for driving and controlling the control valve devices 8L and 8R according to the sign of the deviation value. Is what you do.

[0007]

In the above-described traveling control device, when the hydraulically driven vehicle is traveling by the hydraulic transmissions 3L and 3R, the turning angular velocity of the hydraulically driven vehicle and the traveling speed of the left and right traveling devices 6L and 6R are determined by the angular velocity sensor 10. And the speed detection sensors 11L and 11R sample and detect at any time,
The turning angular speed signal from the angular speed sensor 10 and the traveling speed signal from the speed detecting sensors 11L and 11R are integrated by the calculating means 14, and the current X and Y coordinates of the hydraulically driven vehicle are calculated by the calculating means 14. A traveling position signal is output. The traveling position signal from the calculating means 14 and the target position command signal output from the target position commanding means 15 are calculated by the comparing means 16, and the deviation of the position in the hydraulically driven vehicle is calculated from the comparing means 16. The value is output to the output means 17 side.
7, the control valve devices 8L and 8R are controlled in accordance with the sign of the deviation value. Then, with the control of the control valve devices 8L and 8R, the amount of oil from the hydraulic pumps 1L and 1R to the hydraulic motors 2L and 2R via the displacement control elements 9L and 9R is controlled, and the travel device 6 is controlled.
The rotation speeds of L and 6R are individually controlled. Therefore, when the hydraulically driven vehicle deviates from a preset target traveling locus, the calculating means is based on a turning angular velocity signal from the angular velocity sensor 10 and a vehicle traveling velocity signal from the velocity detecting sensors 11L and 11R. The deviation of the traveling position from the comparing means 16 to the output means 17 based on the traveling position of the hydraulically driven vehicle in X and Y coordinates obtained in 14 and the target position command signal output from the target position command means 15. A value is output, and the traveling control of the hydraulically driven vehicle is constantly performed based on the deviation value, so that the hydraulically driven vehicle can accurately travel along the target traveling locus while correcting the deviation. When the deviation value does not occur, the movement of the hydraulically driven vehicle along the target traveling locus is ensured.

[0008]

FIG. 1 shows an embodiment in which the traveling control device of the present invention is applied to a crawler-type hydraulic drive vehicle. In FIG. 1, the same components as those of FIG. I do.

In FIG. 1, reference numerals 1L and 1R denote swash plates 9L and 9L.
The left and right variable displacement hydraulic pumps with R, 2L and 2R are formed by connecting the left and right constant displacement hydraulic motors, 3L and 3R with the hydraulic pumps 1L and 1R and the hydraulic motors 2L and 2R in a closed circuit. A pair of left and right hydraulic transmissions 4L and 4R are provided with the swash plate 9 for controlling the capacity of the hydraulic pumps 1L and 1R.
L, 9R tilt angle control cylinder, 5 is the hydraulic pump 1
L, 1R; 6L, 6R are left and right traveling devices that are rotated via the hydraulic motors 2L, 2R as the engine 5 is driven; 7 is a charge pump attached to the right hydraulic pump 1R; , 8R are control valve devices connected to the output side of the charge pump 7 and comprising hydraulic servo valves for controlling the swash plate tilt angle control cylinders 4L, 4R.

The output side of the arithmetic unit 12 is connected to each of the control valve devices 8L and 8R. The input side of the arithmetic unit 12 is mounted on the vehicle body of the hydraulically driven vehicle. An angular velocity sensor 10, such as a regular triangular prism piezoelectric vibrating gyroscope, for detecting the turning angular velocity of the vehicle, and speed detecting sensors 11L, 11R for detecting the rotational speed of the axle in each of the traveling devices 6L, 6R are connected. Although the angular velocity sensor 10 is disposed at the center of gravity of the vehicle body in the hydraulically driven vehicle as shown in FIG. 3, it may be disposed at a position deviated from the center of gravity. In this case, a correction value is added to the turning angle signal output from the angular velocity sensor 10. The speed detection sensors 11L and 11R are disposed near the drive shafts of the hydraulic motors 2L and 2R for driving the traveling devices 6L and 6R to detect the rotation speed of the drive shafts or drive wheels. .

As shown in FIG. 2, the arithmetic unit 12 has a subtractor 13 connected to the speed detection sensors 11L and 11R, and the subtractor 13 and the angular velocity sensor 10
And an output side of the target position commanding means 15 and the calculating means 14 based on a target traveling locus from a starting point A to a target position B of the hydraulically driven vehicle in advance. And an output unit 17 connected to the output side of the comparison unit 16. The traveling speed signal NL of the left traveling device 6L output from the left speed detection sensor 11L by the adjuster 13 and the traveling speed signal NR of the right traveling device 6R output from the right speed detection sensor 11L are calculated as follows: The average value N of each of the traveling devices 6L, 6R is calculated based on the following equation 1,

[0012]

(Equation 1)

Based on the measurement result, a traveling speed signal v of the hydraulically driven vehicle is output to the calculating means 14, and the calculating means 14 detects the turning angular velocity of the hydraulically driven vehicle detected by the angular velocity sensor 10. The signal dθ / dt is output.
Then, the traveling speed signal v and the turning angular speed signal dθ / d
is integrated by the arithmetic means 14 based on the following equation (2), thereby obtaining the X coordinate and the Y coordinate of the hydraulically driven vehicle.
The position signal vector L at the coordinates is calculated. That is, X
The current running position in the coordinates and the Y coordinates is determined.

[0014]

(Equation 2)

Further, based on the position signal vector L calculated by the arithmetic means 14 and the target position command signal output from the target position command means 15, the comparing means 16 calculates the deviation of the position in the hydraulically driven vehicle. A value vector ΔL is calculated, and the left and right control valve devices 8L, 8L are output via the output means 17 in accordance with the sign of the vector ΔL and the magnitude of the vector ΔL.
R is driven and controlled.

Next, the operation of the traveling control device having the above configuration will be described. First, as shown in FIG. 4, when the hydraulically driven vehicle travels from the start point A to the target position B, the hydraulic pump 1L is driven by the engine 5 to drive the hydraulic pump.
1R, the hydraulic motors 3L and 3R are driven, and the left and right traveling devices 6L and 6R are operated. By this traveling, the turning angular velocity of the hydraulically driven vehicle and the left and right traveling devices
The running speeds of L and 6R are detected by the angular speed sensor 10 and the speed detecting sensors 11L and 11R by sampling as needed. For example, the rotational speeds of the left and right traveling devices 6L and 6R are different due to the unevenness of the road surface or the state of wetness, so that the hydraulically driven vehicle moves from the starting point A to the target position B.
When the actual travel locus D of the hydraulically driven vehicle deviates outward from the target travel locus C shown by a solid line in FIG. Each traveling speed signal NL output from 11L, 11R,
The running speed of the vehicle is calculated by the adjuster 13 together with the NR. Each of the traveling devices 6L, 6R is
The running speed calculated from the speed is output to the calculating means 14 as a running speed signal v. The operation means 14
The turning angular velocity detected by the angular velocity sensor 10 is output as a turning angular velocity signal dθ / dt. The turning angular velocity signal dθ / dt and the traveling speed signal v are integrated by the arithmetic means 14 , The arithmetic means 1
From 4, the position signal vector L of the X and Y coordinates in the hydraulically driven vehicle, that is, the current traveling position signal in the X and Y coordinates is output to the comparing means 16. The comparing means 16 calculates the position signal vector L and a preset target position command signal output from the target position command means 15, and calculates the deviation of the current traveling position in the hydraulically driven vehicle. A value vector ΔL is calculated, and the output means 17 based on the deviation value vector ΔL is calculated.
The left and right control valve device 8L or 8R is controlled by the output from the controller. That is, the control valve device 8L or 8R
When the output signal corresponding to the deviation value vector ΔL is output, the swash plate tilt angle control cylinder 4L or 4R operates with the pressure oil from the charge pump 7, and one of the swash plates in the hydraulic pumps 1L and 1R. The tilt angle of the 9L or 9R with respect to the neutral position is changed to be large, and the hydraulic motor 2L or 2R is
The amount of oil reaching the side is controlled to increase, and the rotation speed of the traveling device 6L or 6R is controlled to increase. That is, for example, the current travel locus D of the hydraulically driven vehicle deviates to the right with respect to the target travel locus C, and the position signal vector L from the calculating means 14 is output from the target position instructing means 15 to the target position command signal. Smaller than
When the deviation value vector ΔL is positive, the right control valve device 8R operates, the inclination angle of the swash plate 9R in the right hydraulic pump 1R increases, and a large amount of oil is supplied to the right hydraulic motor 2R. The rotation speed of the right traveling device 6R is higher than that of the left traveling device 6L, and the hydraulically driven vehicle is corrected to the left so as to follow the target traveling locus C, that is, to have a deviation value of zero. It is. on the other hand,
Conversely, the current travel locus D of the hydraulically driven vehicle deviates to the left with respect to the target travel locus C, and the position signal vector L from the arithmetic means 14 is output from the target position instructing means 15. When the deviation value vector ΔL is negative and the deviation value vector ΔL is negative, the left control valve device 8L operates, the inclination angle of the swash plate 9L in the left hydraulic pump 1R increases, and the left hydraulic pressure increases. Motor 2
L is supplied with a large amount of oil, the rotation speed of the left traveling device 6L is made higher than that of the right traveling device 6R, and the hydraulically driven vehicle follows the target traveling locus C, that is, the deviation value is zero. It is corrected to the right so that Further, the position signal vector L from the calculating means 14
Is the same as the target position command signal output from the target position command means 15 and the deviation value vector ΔL is zero, the hydraulically driven vehicle travels straight along the target travel locus C. Accordingly, when the vehicle deviates from the target traveling locus C as described above, the traveling speed is simultaneously detected together with the turning angular velocity to determine the current position, and the deviation value of the position with respect to the target traveling locus C is calculated to obtain a deviation value of zero. Since the position is corrected so that it becomes, unlike the previously proposed traveling control device that detects and controls only the turning angular velocity,
The vehicle can travel along an arbitrary target traveling locus C as well as straight traveling.

In the above embodiment, the hydraulic pumps 1L, 1R constituting the hydraulic transmissions 3L, 3R are of variable displacement type, and the hydraulic pumps 1L, 1R are controlled by the displacement control elements 4L, 4R. Although the valve devices 8L and 8R are provided, in the present invention, the hydraulic motors 2L and 2R are of variable displacement type, and the displacement control elements 4L and 4R and the control valve devices 8L and 8L are provided on the hydraulic motors 2L and 2R. 8R may be provided. Although the piezoelectric velocity gyro is used as the angular velocity sensor 10, an optical fiber gyro, a laser gyro, or a rate gyro may be used.

[0018]

As described above, in the travel control device of the present invention, the displacement control element 4L provided on at least one of the hydraulic pumps 1L, 1R and the hydraulic motors 2L, 2R constituting the hydraulic transmissions 3L, 3R. , 4R, an angular velocity sensor 10 for detecting the turning angular velocity of the hydraulically driven vehicle, and the left and right traveling devices 6L, 6R.
Left and right speed detection sensors 11L, 11 for detecting the speed of R
Computing means 14 for integrating R, a turning angular velocity signal from the angular velocity detecting sensor 10 and a vehicle running velocity signal from the left and right velocity detecting sensors 11L and 11R, and outputting a position signal at X and Y coordinates; Target position command means 15 for outputting a position command signal based on a preset target travel locus; comparison means 16 for calculating the position signal and the target position command signal to output a position deviation value; Control valve devices 8L, 8R according to the sign of
And output means 17 for controlling the driving of the hydraulically driven vehicle, so that the vehicle can travel while constantly comparing the current traveling position in the X coordinate and the Y coordinate with the target position. Can be
This allows the hydraulically driven vehicle to travel accurately along an arbitrary target travel locus from the starting point to the target position.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view showing a travel control device of the present invention.

FIG. 2 is a functional block diagram showing an arithmetic unit of the traveling control device.

FIG. 3 is a schematic plan view of a hydraulic drive vehicle.

FIG. 4 is an explanatory diagram illustrating a traveling control state of the hydraulically driven vehicle by the traveling control device.

FIG. 5 is a schematic explanatory diagram of a traveling control device proposed previously.

FIG. 6 is an explanatory diagram illustrating a traveling control state of the hydraulically driven vehicle by the traveling control device.

[Description of Signs] 1L, 1R Hydraulic pump 2L, 2R Hydraulic motor 3L, 3R Hydraulic power transmission 4L, 4R Capacity control element 6L, 6R Traveling device 8L, 8R Control valve device 10 Angular velocity sensor 11L, 11R Speed detection sensor 14 Calculation means 15 Target position command means 16 Comparison means 17 Output means

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI B62D 13:00

Claims (1)

(57) [Claims] 1. A hydraulic pump 1L, 1R and a hydraulic motor 2.
L, 2R and a pair of hydraulic transmissions 3 connected in a closed circuit
L, 3R, and a driving control device for a hydraulically driven vehicle that independently drives the left and right traveling devices 6L, 6R by the respective hydraulic motors 2L, 2R.
3R, a displacement control element 9 provided in at least one of the hydraulic pumps 1L, 1R and the hydraulic motors 2L, 2R.
L, 9R, and a control valve device 8L, 8R, and an angular velocity sensor 10 for detecting a turning angular velocity of the hydraulically driven vehicle.
And left and right speed detection sensors 11L and 11R for detecting the speeds of the left and right traveling devices 6L and 6R, a turning angular speed signal from the angular speed detection sensor 10 and a vehicle running speed signal from the left and right speed detection sensors 11L and 11R. Calculating means 14 for outputting a position signal at the X coordinate and Y coordinate, a target position commanding means 15 for outputting a position command signal based on a preset target travel locus, and the position signal and the target position command. A hydraulically driven vehicle comprising: a comparison unit 16 that calculates a signal and outputs a position deviation value; and an output unit 17 that drives and controls the control valve devices 8L and 8R according to the sign of the deviation value. Travel control device.