JP2842540B2 - Control method and control device for vehicle basic characteristic tester - Google Patents

Description

Description: TECHNICAL FIELD The present invention generally relates to a control method and a control device for a vehicle basic characteristic tester, and more particularly, to a front-rear direction, a left-right direction, and a right-left direction on a tire installation surface of the vehicle basic characteristic tester. The present invention relates to a control method and a control device for zero-controlling a load in a directional or rotational direction.

[Conventional technology]

The vehicle basic characteristic tester is generally used to test various basic characteristics of a vehicle, and can move in each of the up and down, front and rear, and left and right directions that each plunger of the four cylinder mechanisms of the vehicle has at its top. Each tire of the vehicle under test is mounted on a rotary table, and a test is performed.

Each of the cylinder mechanisms has a configuration as shown in a partial cross-sectional view of FIG. 4, and an electrohydraulic servo type vertical vibration actuator 11 is installed on a base B. The vertical vibration actuator 11 includes a cylinder 11a to which hydraulic pressure is supplied via a servo valve (not shown), and a piston rod which is fitted to the cylinder 11a in a liquid-tight manner and reciprocated in the vertical direction, that is, the Z direction by the hydraulic pressure. A vertical movement table 11c having a flat surface perpendicular to the Z direction at the top is formed at the upper end of the piston rod 11b.

On the vertical movement table 11c, a front / rear / left / right movement table 12 is mounted on a flat surface via rolling rollers 12a so as to be movable in the front / rear direction (X direction) and the left / right direction (Y direction). Electro-hydraulic servo type front and rear vibration actuator (not shown behind rear and front and rear table 12)
And an electrohydraulic servo-type left and right vibration actuator 13 are fixed. The front-rear left-right movement table 12 has a front-rear vibration actuator piston rod on one of its front and rear end faces, and a left-right vibration actuator on one of the left-right end faces.
13 piston rods 13a are connected respectively,
Each connection is made such that when the other actuator applies vibration, the front / rear / left / right movement table 12 in that direction is allowed to move.

In the front-rear left-right movement table 12, a rotation table 14 is rotatably arranged at the center of the upper surface via a rolling roller 14a, and a rotation actuator 15 for rotating the rotation table 14 is rotated in a center recess thereof. It is fixed so as not to move in the direction and to be able to move slightly in the vertical direction. The output shaft 15a of the rotary actuator 15 is connected to the rotary table 14. The rotary table 14 includes four piezoelectric three-axis sensors 14b that detect loads in three directions of X, Y, and Z, and a pair of disks 1
4c. Further, between the output shaft 15a of the rotary actuator 15 and the rotary table 14, a rotary torque sensor 16 for detecting a rotary torque is provided. The tire T of the vehicle to be tested is placed on the upper surface of the rotary table 14.

Reference numeral 17 denotes a displacement sensor that detects the amount of vertical displacement of the vertical movement table 11c. Although not shown in the drawing, a displacement sensor for detecting the displacement of the front-rear and left-right movement table 12 by the front-rear actuator and the left-right actuator 13 in the front-rear and left-right directions, and the rotation amount of the rotation table 14 by the rotation actuator 15 Is also provided.

In the above-described vehicle basic characteristic tester, the rotary table 14 on which the tires T are installed can be moved back and forth (X), left and right (Y), up and down (Z) and rotation (θ). Is performed by a combination of each vector of X, Y, Z, and θ.
In some cases, servo control to make the load value or torque value related to X, Y, and θ except for zero become necessary.

The reason why the zero load servo control is required is as follows. It is sufficient to mechanically create a mechanism with zero friction coefficient mechanically in the vector element that should originally be tracked to zero, but there is a limit to zero force because mechanical bearings also have a finite value in practical use. This is because the mechanism using the bearings described above is bulky and complicated, and is not practical. Therefore, the zero-load servo control is adopted as a solution.

In this zero-load servo control, a structure is adopted in which vector actuators for each of the X, Y, and θ axes are directly attached to the rotary table 14 that is the tire installation surface, and the axis for which the load is to be reduced to zero,
For example, when received from the tire T in the θ direction on the θ axis,
It is intended to realize zero torque by detecting the torque applied to θ and controlling the value to be an example so that the direction is dynamically free.

[Problems to be solved by the invention]

Generally, a test is periodically performed for one test item. However, since the vibration response characteristics of the vehicle under test are incorporated in the test load control loop, the control system, that is, the loop gain of the loop transfer function is increased. And the loop becomes unstable, and the loop gain cannot be raised unnecessarily.
In general, a steady-state error occurs due to the deviation of the zero position of the spool of the servo valve and the static friction or dynamic friction between the actuator and the applied point. However, since the loop gain is finite, it is necessary to reduce the steady-state error value. There is a limit.

An example of the actual steady-state deviation will be described using a steering gear ratio test as an example. The front tire T of the vehicle is mounted on the rotary table 14 as shown in FIG. When the steering wheel H is rotated left and right with the torque command signal (FIG. 6 (c)) set to zero and the rotary actuator 15 is controlled to zero torque (FIG. 6 (a)).
In this case, the torque generated on the tire contact surface should ideally be completely zero, but in practice, predetermined torques Et ₁ and Et ₂ are generated by right and left rotation (FIG. 6 (b)). ).

FIG. 7 shows the relationship between the tire rotation angle and the tire rotation torque. In Figure 7, T ₁ is the steady-state deviation, T ₂ due to the deviation in the null position of the spool of the servo valve is a steady state error due to static friction and dynamic friction.

Accordingly, the present invention has been made in view of the above-described problems of the related art, and has been made in view of the above-described conventional technology. It is an object to provide a control method and a control device for a basicity tester.

[Means for solving the problem]

A control method of a vehicle basic characteristic tester according to the present invention for solving the above-mentioned problems includes a table movable in front and rear, left and right and rotational directions, and independently driving the table in each of the directions. Actuators, and a tire of a vehicle mounted on the table of the vehicle basic characteristic tester, comprising: a load detecting unit configured to detect a load acting on the table in each of the directions. A control method for performing zero-load servo control of the actuator such that when repeatedly moved in one of the directions, the load acting on the table detected by the load detecting means in the direction becomes zero. When the tire mounted on the table is moved for at least one cycle, the tire is detected by the load detecting means. The load acting on the table is collected and stored as load data, and after the end of the cycle, the stored load data is inverted to create a load command signal, and the actuator is determined based on the created load command signal. Is servo-controlled.

A control device for a vehicle basic characteristic tester according to the present invention for solving the above-mentioned problems includes a table movable in the front-rear, left-right, and rotation directions, and independently drives the table in each of the directions. Actuators, and a tire of a vehicle mounted on the table of the vehicle basic characteristic tester, comprising: a load detecting unit configured to detect a load acting on the table in each of the directions. A controller that performs zero-load servo control of the actuator so that when the actuator repeatedly moves in one of the directions, the load acting on the table detected by the load detecting means in the direction becomes zero. When the placed tire is moved for at least one cycle, the load is detected by the load detecting means. Storage means for collecting and storing the load acting on the cable as load data, and load command signal creating means for creating a load command signal by inverting the load data stored in the storage means after the end of the cycle. The servo control of the actuator is performed based on the load command signal created by the load command signal creating means.

(Operation)

In the above configuration, the vehicle tires are placed on a table that is movable in the front-rear, left-right, and rotation directions, and is driven independently by actuators in each direction, and the tires placed on the table are moved in one direction. When the vehicle repeatedly moves, the load acting on the table in that direction is detected by the load detecting means, and the zero-load servo control of the actuator is performed so that the detected load becomes zero. The load acting on the table detected by the load detecting means when moved during is collected and stored as load data, and after the end of the cycle, the stored load data is inverted to generate a load command signal, The actuator is servo-controlled based on the created load command signal. Therefore, when the actuator is operated based on the created load designation signal, no load is detected in the output of the load detection means, and even if the tire placed on the table is moved, no load acts on the table. No more.

〔Example〕

 Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a control device for implementing a control method of a vehicle basic characteristic tester according to the present invention. The control device is a microcomputer (CPU) 2 that operates according to a predetermined program.
Has zero. D / A conversion circuits 22 and 23 and an A / D conversion circuit 24 are connected to the CPU 20 via a bus 21.

The D / A conversion circuit 22 converts the handle angle command signal composed of a digital signal supplied to the input into an analog signal and outputs the analog signal, which is input to the + input of the addition point 25. Addition point
The output signal of 25 is input to a servo valve 27a of an electro-hydraulic handle drive motor 27 via a servo amplifier 26, and controls the servo valve 27a to move the handle drive motor 27 to a predetermined angular position. Output shaft 27b of handle drive motor 27
Is connected to a handle shaft H of the vehicle via a rotation angle sensor 28. The rotation angle sensor 28 outputs a rotation angle signal corresponding to the rotation angle of the handle shaft H, and applies this signal to the minus input of the addition point 25 via the angle amplifier 29, whereby the addition point 25
Is output as a deviation signal which is the difference between the steering wheel angle command signal and the rotation angle signal.
Is driven to the angular position commanded by the command signal.

The D / A conversion circuit 23 converts the torque command signal, which is a digital signal supplied to the input, into an analog signal and outputs the analog signal, which is input to the + input of the addition point 30. The output signal of the addition point 30 is input to the servo valve 15b of the electrohydraulic rotary actuator 15 via the servo amplifier 31, and the servo valve 15b
To operate the rotary actuator 15 at a predetermined angular position. The output shaft 15a of the rotary actuator 15 is connected to the rotary table 14 via a torque sensor 16. The torque sensor 16 outputs a torque detection signal corresponding to the rotational torque acting on the rotary table 14 and applies this to the-input of the addition point 30 via the torque amplifier 32,
It is supplied to the input of the A / D conversion circuit 24. This gives an additional point 3
At the output of 0, a deviation signal which is a difference between the torque command signal and the torque detection signal is output, whereby the torque commanded by the torque command signal is applied to the rotating table 14. Further, the torque detection signal output from the torque amplifier 32 is converted into a digital signal by the A / D conversion circuit 24, taken into the CPU 20 via the bus 21, and stored in the internal memory.

After outputting the handle angle command signal for one cycle, the CPU 20 reads the torque signal stored in the internal memory, and uses the inverted signal as a new torque command signal as a D / D signal.
It is supplied to the input of the A conversion circuit 23.

The control method of the present invention, which is executed using the control device having the above configuration, will be described with reference to the timing chart of FIG.

First, the CPU 20, as shown in FIG.
A one-cycle handle angle command signal that changes between θ and −θ is output via the D / A conversion circuit 22, and the handle drive motor 27 is controlled by a deviation signal between the command signal and the rotation angle signal from the rotation angle sensor 28. Servo control is performed to drive the handle according to the command signal. The CPU 20 also outputs a zero torque command signal via a D / A conversion circuit 23 at this time, as shown in FIG. 2 (c), and outputs a deviation signal between the command signal and a torque detection signal from the torque sensor 16. Rotary actuator 15
Is driven to rotate the rotary table 14 in accordance with the command signal. A torque detection signal as shown in FIG. 2 (b) is generated at the output of the torque sensor 16, and this torque detection signal is output to the A / D. The data is collected by the CPU 20 via the conversion circuit 24 and stored in its internal memory. The amplitude of the first half cycle of the torque detection signal stored in the internal memory is Et ₁ , and the amplitude of the second half cycle is Et ₂ .

Then CPU20 outputs the steering wheel angle command signal for the next cycle, but the output of the torque detection signal shown in FIG. 2 (c) obtained by inverting the torque detection signal Et ₁ and Et ₂ stored in the internal memory in this case I do. As a result, after the second cycle, the torque detection signal generated by the torque sensor 16 becomes substantially zero as shown in FIG. 2 (b).

In performing the above-described operation, the CPU 20 performs the work shown in the flowchart of FIG.

The CPU 20 starts operation, for example, when the power is turned on, initializes in the first step S1, and clears the flag to “0”. Then proceed to step S2,
Here, it waits for a test start operation to be performed by an operation unit (not shown), and if the test start operation is performed, the process proceeds to step S3. In step S3, after outputting the steering wheel angle command signal, the process proceeds to step S4, where it is determined whether the flag is "1" or a ratio. When the determination in step S4 is NO, that is, when the flag is "0", the process proceeds to step S5,
Here, a zero torque command signal is output. Then step S6
To read the torque detection signal and store it in the internal memory.

Then, the process proceeds to step S7, in which the steering angle command signal is set to 1
It is determined whether or not output has been performed for the number of cycles, and when this determination is NO, the process proceeds to step S8, where it is determined whether or not a test end operation has been performed in the operation unit, and when the determination is NO, the process returns to step S3. Then, the next steering wheel angle command signal is output, and the above-described steps S4 to S8 are repeatedly executed until the determination in step S7 or S8 is YES. Step now
If the determination in S7 is YES, that is, if a handle angle command signal for one dummy cycle consisting of one cycle has been output, the process proceeds to step S9, where the flag is set to "1", and then the process proceeds to step S8. Thereafter, the determination in step S4 becomes YES and the process proceeds to step S10, where
In S6, the torque detection signal for one cycle stored in the internal memory is inverted and output as a new torque command signal. After executing step S10, the process returns to step S3 via step S8, and thereafter, steps S3, S10, and S8 are repeatedly executed until a test end operation is performed by the operation unit and the determination in step S8 becomes YES. If the determination in step S8 is YES, the process proceeds to step S11, where the flag is cleared, and a series of work ends.

The CPU 2 operating according to the flowchart of FIG.
The internal memory of 0 is a load acting on the rotating table 14 detected by the torque sensor 16 as a load detecting means when the tire T mounted on the rotating table 14 is moved during a dummy cycle consisting of at least one cycle. Acting as storage means for collecting and storing a certain torque as load data, the CPU 20 itself also serves as load command signal creating means for creating a load command signal by inverting the load data stored in the internal memory after the end of the dummy cycle. In operation, the rotary actuator 15 is servo-controlled based on the load command signal created by the CPU 20.

Further, in the above-described embodiment, a case is described in which the torque acting on the rotary table 14 is controlled to be zero by a change in the rotation angle due to the operation of the steering wheel of the vehicle,
The present invention is equally applicable to control for making the load in the front-rear direction and the load in the left-right direction acting on the rotary table 14 by the movement of the tire T in the front-rear direction and the left-right direction zero.

(Effect)

As described above, according to the present invention, a load acting on the table detected when the tire placed on the table has been moved for at least one cycle is collected and stored as load data, and after the end of the cycle, Inverting the stored load data to create a load command signal, servo-controlling the actuator based on the created load command signal, and operating the actuator based on the inverted and created load command signal When the tire mounted on the table is moved, no load is applied to the table, so the gain of the servo system loop is set to be too large and the system becomes unstable. Can be reduced.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of a control device for a vehicle basic characteristic tester according to the present invention, FIG. 2 is a diagram showing signal waveforms of various parts in FIG. 1, and FIG. 3 is a CPU in FIG. 4 is a diagram showing one cylinder mechanism of the vehicle basic characteristic tester, FIG. 5 is a perspective view showing an example of a case where a steering gear ratio test is performed, and FIG. 6 is a conventional control. FIG. 7 is a signal waveform diagram for explaining a method, and FIG. 7 is a diagram for explaining a problem of a conventional test. 13 …… Left and right actuator (actuator), 14…
... Rotating table (table), 15 ... Rotary actuator (actuator), 15b ... Servo valve, 16 ... Torque sensor (load detecting means), T ... Tyre, 20 ... CP
U (storage means), 20 CPU (load command signal creation means).

Claims (2)

(57) [Claims] 1. A table movable in front, rear, left, right and rotational directions, an actuator for independently driving the table in each of the directions, and detecting a load acting on the table in each of the directions. When a tire of the vehicle is mounted on the table of the vehicle basic characteristic tester including a load detecting unit and the tire mounted on the table is repeatedly moved in one of the directions,
In a control method, the actuator mounted on the table is subjected to at least one cycle of zero-load servo control so that a load acting on the table detected by the load detecting means in the direction becomes zero. The load acting on the table detected by the load detection means when moved during the period is collected and stored as load data, and after the end of the cycle, the stored load data is inverted to create a load command signal, A servo control method for the actuator based on the generated load command signal, the method for controlling a vehicle basic characteristic tester. 2. A table movably in the front, rear, left, right, and rotation directions, an actuator for driving the table independently in each of the directions, and detecting a load acting on the table in each of the directions. When a tire of the vehicle is mounted on the table of the vehicle basic characteristic tester including a load detecting unit and the tire mounted on the table is repeatedly moved in one of the directions,
In a control device for performing zero load servo control of the actuator so that a load acting on the table detected by the load detecting means in the direction becomes zero, a tire mounted on the table is moved for at least one cycle. A storage unit that collects and stores the load acting on the table detected by the load detection unit as load data, and after the end of the cycle, inverts the load data stored in the storage unit and outputs a load command signal. A control device for a vehicle basic characteristic tester, comprising: load command signal generating means for generating; and servo-controlling the actuator based on the load command signal generated by the load command signal generating means.