JP3368522B2 - Power steering test equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is a bench test of steering reaction force characteristics of a power steering while changing specifications of a vehicle or tires, driving conditions and running environment, or specifications of a power steering device. The present invention relates to a power steering test device that can be easily and efficiently simulated.

[0002]

Related Background Art A power steering device utilizing hydraulic pressure is widely used as a mechanism for reducing the steering force of a steering wheel. This type of power steering device basically includes a power cylinder that is driven by switching a hydraulic circuit, and a control valve (power steering that controls switching of the hydraulic circuit for the power cylinder according to the steering angle of the steering wheel and its hydraulic pressure). Valve).

In order to simulate a steering reaction force characteristic of such a power steering device by a bench test, a load (reaction force) is generally applied to the power cylinder by using a reaction force actuator connected to the output shaft of the power cylinder. )
Is given. The reaction force (load) F generated by using the reaction force actuator is obtained in accordance with the steering angle θh of the steering wheel in accordance with the map data of the steering reaction force preset based on the vehicle speed and the like. Has become.

[0004]

The steering reaction force of the power steering varies variously depending on the specifications of the vehicle and tires, operating conditions such as vehicle speed, and the traveling environment such as cross wind strength. Therefore, when simulating the steering reaction force characteristics under various conditions, it is necessary to prepare a large number of steering reaction force maps corresponding to the conditions, which requires a great deal of labor. Moreover, data collection itself when creating the steering reaction force map is extremely difficult. By the way, Japanese Patent Laid-Open No. 4-1139
Japanese Patent Laid-Open No. 07-2007 discloses a technique in which a steering reaction force is calculated according to a steering angle, a tire slip angle, etc., and the steering reaction force is applied to a steering wheel (handle) to perform a steering test. However, there remains a problem in what kind of traveling condition the steering reaction force is calculated, and it is necessary to prepare a large number of calculation functions corresponding to the steering reaction force map in accordance with the traveling conditions.

When it is desired to change the valve characteristics of the power steering device, it is necessary to manufacture a plurality of types of control valves according to their specifications and to selectively incorporate them into the power steering device. Therefore, a lot of labor and cost are required for the trial manufacture and evaluation, and there is a problem that the valve characteristics cannot be easily changed.

Moreover, as described above, the steering reaction force and the control valve characteristics change depending on whether the power steering device is tested as a stand-alone unit on a bench or when the power steering device is mounted on a vehicle. Therefore, there is a problem that an actual vehicle running test is required to confirm the actual steering feeling of the power steering, which is troublesome and time consuming. In particular, even if the same power steering device is used, if the type of vehicle equipped with this device is different, it is necessary to confirm the steering feeling of the power steering by conducting an actual vehicle running test for each vehicle type.

In Japanese Patent Laid-Open No. 4-133858, steering wheel operation is achieved by providing a speed increasing means and a coupler having a shock absorbing property in a power transmission system between a motor for applying a reaction force and the steering wheel. A technique for evaluating sexuality / operation feeling is disclosed. However, this technique has a problem in that the characteristic itself of the power steering device cannot be evaluated.

The present invention has been made in view of the above circumstances, and its purpose is to change the specifications of the vehicle and tires, the operating conditions and the driving environment, or the specifications (valve characteristics) of the power steering device. ), The steering reaction force characteristics of the power steering can be simplified by a bench test.
Another object of the present invention is to provide a power steering test device that can be simulated efficiently.

[0009]

In order to achieve the above-mentioned object, a power steering test apparatus according to the present invention is driven by switching hydraulic circuits by the operation of a control valve driven according to the steering angle of a steering wheel. A power steering device including a power cylinder is provided, and reaction force adding means for generating a steering reaction force to the power steering device is connected to an output shaft of the power cylinder to simulate a steering reaction force characteristic of the power steering. A power steering test device that
A base valve characteristic for storing the base valve characteristic Vb by measuring a steering torque T and a power steering pressure P of the power steering apparatus to obtain a base control valve characteristic (base valve characteristic Vb) which is a reference of the power steering apparatus. A storage means, a virtual valve characteristic setting means for setting a virtual control valve characteristic (virtual valve characteristic Vt) to be realized in the power steering device, and a steering angle according to a vehicle motion model previously obtained from vehicle specifications and a motion equation. steering reaction force calculating means for obtaining a steering reaction force Fa with respect to θh,
The steering reaction force Fa is corrected according to the base valve characteristic Vb, the virtual valve characteristic Vt, and the steering torque T (steering reaction force correction means), and the reaction force addition means
The corrected steering reaction force F is characterized in that so as to impart to the power steering device.

[0010] That the steering reaction force Fa, which is determined according to the vehicle motion model, base valve characteristic Vb, and corrected in accordance with the virtual valve characteristic Vt, and the steering torque T, the corrected
By applying the steering reaction force F as a load to the power steering device, the steering reaction force characteristic can be accurately applied. According to a second aspect of the present invention, in particular, in the steering reaction force calculating means, the steering reaction force with respect to the steering angle θh based on the analysis result of the vehicle motion model according to the specifications of the vehicle and tires, the driving state, and the traveling environment. Fa
It is characterized in that the steering reaction force under various conditions is efficiently obtained without preparing an enormous steering reaction force map.

Further, in the invention according to claim 3, as the steering reaction force correcting means, a difference ΔP between the base valve characteristic Vb and the virtual valve characteristic Vt is obtained as a correction pressure characteristic, and the correction pressure characteristic and the steering It is characterized in that the corrected steering reaction force F is obtained by subtracting the reaction force correction value f obtained based on the torque T from the steering reaction force Fa. That is, the difference ΔP between the base valve characteristic Vb and the virtual valve characteristic Vt is obtained as the correction pressure characteristic, so that the steering reaction force Fa can be easily and efficiently corrected.

Further, according to the invention of claim 4, in the virtual valve characteristic setting means, the virtual valve characteristic Vt is variably set according to the valve characteristic of the power steering device to be realized. It is characterized in that desired valve characteristics are set without trial production of various control valves.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a power steering test apparatus according to the present invention will be described below with reference to the drawings. FIG. 1 is a functional block configuration diagram showing a schematic configuration of a power steering test apparatus according to this embodiment.
In the figure, 10 is a power steering device installed on the test stand. The power steering device 10 has an integral type, a semi-integral type, and
Although it is classified as a linkage type or the like, basically, the control valve 12 that is driven according to the steering angle θh of the steering wheel 11, and the hydraulic circuit is switched by the operation of this control valve 12 and is hydraulically controlled and driven. And a power cylinder 13.

Reference numeral 14 in the figure is the control valve 1 described above.
2 is a hydraulic device that is connected to 2 and constitutes a hydraulic circuit for the power cylinder 13, and 15 is the handle 11
Is a rod that is connected to and is driven to move in accordance with the steering angle θh. The power cylinder 13 connected to the rod 15 is hydraulically driven to operate the handle 11
Plays a role of assisting the movement of the rod 15 by steering. A sensor 17 is incorporated in the shaft 16 of the steering wheel 11, and the sensor 17 detects the steering wheel angle (steering angle) θh and the steering torque T, respectively.

A reaction force actuator 18, which is servo-controlled as will be described later, is provided on the test table as a reaction force adding means connected to the power cylinder 13. By driving the reaction force actuator 18, a steering reaction force F corresponding to the steering angle θh of the steering wheel 11 is applied to the power steering device 10, specifically, to the output shaft of the power cylinder 13. Has become.

Now, in the present apparatus in which the power steering device 10 and the reaction force actuator 18 are installed on the test table as described above, the control for controlling the reaction force F by the reaction force actuator 18 in accordance with the steering angle θh of the steering wheel 11. The block 20 is configured as follows. That is, the control block 20 is realized by an arithmetic control unit mainly composed of a microprocessor,
Basically, it comprises a base valve characteristic acquisition means 21, a virtual valve characteristic setting means 22, a steering reaction force calculation means 23, and a steering reaction force correction means 24.

The base valve characteristic acquisition means 21 measures the steering torque T and the power steering pressure P of the power steering device 10 accompanying the steering of the steering wheel 11,
As a change characteristic (TP characteristic) of the power steering pressure P with respect to the steering torque T, the power steering device 1
The valve characteristic of 0 itself (base valve characteristic Vb) is obtained. Further, the virtual valve characteristic setting means 22 arbitrarily sets a valve characteristic (virtual valve characteristic Vt) which is to be virtually realized in the power steering device 10. The virtual valve characteristic Vt is, for example, a key for the arithmetic control unit. It is set arbitrarily by input.
Specifically, the virtual valve characteristic Vt is set by changing the power steering pressure P with respect to the steering torque T as shown by the broken line in the figure with respect to the base valve characteristic Vb shown by the solid line.

The correction pressure calculation means 25 calculates the difference ΔP between the base valve characteristic Vb obtained by the base valve characteristic acquisition means 21 as described above and the virtual valve characteristic Vt set in the virtual valve characteristic setting means 22. The difference ΔP (correction data) obtained as a characteristic is output to the steering reaction force correction means 24. The correction pressure calculation means 25 is not an independent calculation means, but the steering reaction force correction means 2
It may be realized as a part of the function of 4.

On the other hand, the steering reaction force calculating means 23 includes not only the steering angle θh of the steering wheel 11 detected by the sensor 17 but also the vehicle speed V set by key input, vehicle specifications that can be arbitrarily changed, and tires. A vehicle motion model analysis means 26 for three-dimensionally analyzing a motion model of the vehicle based on various data such as characteristics and further setting information such as a driving state and a traveling environment is provided. This vehicle motion model analysis means 26
For example, the document “Mitsubishi Motors Technical Review” 1995
As described in detail in No. 7 P50-52 (improvement of movement performance by suspension alignment control), as shown in FIG. 2, the yaw-direction momentum Az and the roll-direction momentum lx, based on the center of gravity of the vehicle, are used. Further, the lateral momentum and the like are analyzed, and the front tire slip angle βf and the rear tire slip angle βr are, for example, βf = (δf− (y * + AL · ψ *) / U−XX1 · φ) / Q
1 βr = (-(y * + BL * [psi] *) / U-XX2 * [phi]) / Q2. However, in the above equation, δf; front wheel (front) actual steering angle y; lateral displacement (y *; lateral velocity) AL; center of gravity front wheel axle distance BL; center of gravity rear wheel axle distance ψ; yaw angle (ψ *; yaw angular velocity) ) Φ: Roll angle U; Front-rear direction speed XX1; Front steer coefficient XX2; Rear steer coefficient Q1; Front cornering power coefficient Q2; Rear cornering power coefficient.

[0020]

[Outer 1]

The steering reaction force calculating means 23 is set to 3 as described above.
The steering angle θ
The steering reaction force Fa with respect to h is calculated as, for example, reaction force Fa = front tire slip angle βf x cornering power x (caster trail / knuckle arm length). However, the cornering power is determined according to the ground load, the self-aligning torque (SAT), and the drive braking correction.

Basically, in order to apply the steering reaction force Fa thus obtained to the power cylinder 13, the reaction force actuator 1 is operated via a servo controller or the like.
By driving 8, the reaction force corresponding to the steering angle θh is applied to the power steering device 10. Then, the steering feeling of the power steering is simulated.

By the way, in this device, as described above, the steering angle θ
The steering reaction force Fa obtained according to h is subjected to reaction force correction by the steering reaction force correction means 24 described above, and then the reaction force actuator 18 is driven. That is, the steering reaction force correction means 24 is the correction pressure calculation means 25.
According to the correction pressure characteristic obtained in
The correction pressure ΔP corresponding to is calculated. Then, the steering reaction force correction means 24 obtains a reaction force correction value f for the steering reaction force Fa according to the cylinder area (P / C area) of the power cylinder 13 based on the correction pressure ΔP, and the reaction force correction value f is obtained. By subtracting from the steering reaction force Fa, the reaction force F to be applied to the power steering device 10 via the reaction force actuator 18 is set. That is, the steering reaction force correcting means 24 corrects the steering reaction force Fa according to the correction pressure characteristic to obtain the reaction force command value for the reaction force actuator 18.

In other words, the servo controller 27
Sets the steering reaction force characteristic, which is shown as a change in the reaction force F with respect to the steering angle θh as shown in the drawing, to hysteresis according to the reaction force command value given as described above, and drives the reaction force actuator 18 according to this characteristic. Then, the reaction force F to the power steering device 10 is generated according to the steering angle θh at that time.

FIG. 3 shows a schematic flow of the simulation processing in the apparatus configured as described above. This process basically starts by measuring the valve characteristic of the power steering device installed on the test bench using a prepared test menu and storing the characteristic (base valve characteristic Vb) in the memory. [Step S1]. Then, the virtual valve characteristic to be simulated by this device is input to the memory on the arithmetic and control unit to set the virtual valve characteristic Vt [step S
2]. In this state, the difference ΔP between the base valve characteristic Vb and the virtual valve characteristic Vt is obtained, and the correction pressure characteristic with respect to the steering torque T is obtained as described above [step S3].

Thereafter, the steering reaction force is obtained based on the analysis result of the vehicle motion model, and the steering reaction force is corrected according to the corrected pressure characteristic to obtain the reaction force command value under the virtual valve characteristic. Is output to the servo controller [step S4]. The power steering device 10 is operated under the conditions set as described above, and the steering wheel 11 is operated.
The steering force simulation under the virtual valve characteristic is executed by steering [step S5].

Thus, according to the device thus configured, the reaction force Fa corresponding to the steering angle θh of the steering wheel 11 is essentially transmitted via the reaction force actuator 18 according to the base valve characteristic Vb of the power steering device 10. When applied, the reaction force F corrected according to the virtual valve characteristic Vt in the steering reaction force correction means 24 is generated via the reaction force actuator 18 to generate the power steering device 10.
Added to. In addition, the reaction force correction in the steering reaction force correction means 24 is performed based on the difference between the base valve characteristic Vb of the power steering device 10 and the virtual valve characteristic Vt. As a result, the reaction force F actually applied to the power steering device 10 is obtained by correcting the base valve characteristic Vb by an amount corresponding to the difference described above.
That is, it is equal to that generated under the virtual valve characteristic Vt.

Therefore, according to this device, the virtual valve characteristic Vt arbitrarily set on the virtual valve characteristic setting means 22 is realized on the power steering device 10 without changing the base valve characteristic Vb of the power steering device 10. However, it becomes possible to simulate the steering force. Moreover, by variably setting the virtual valve characteristic Vt in accordance with various demands, it becomes possible to efficiently execute the steering force simulation under the set valve characteristic. Particularly, as in the past, a plurality of types of control valves 12 and power cylinders 1 according to various specifications are used.
The steering force simulation can be efficiently executed by a method of arbitrarily setting the virtual valve characteristic Vt on the single power steering device 10 without trial production of No. 3.

Further, in this apparatus, since the vehicle motion model is analyzed and the steering reaction force Fa related to the steering angle θh of the steering wheel 11 is calculated based on the analysis result, it is set in the vehicle motion model analysis means 26, for example. By simply changing the specifications of the vehicle and the specifications of the tire (tire characteristics), it is possible to adaptively obtain the steering reaction force Fa that changes according to these specifications. Furthermore, if you give information about the road environment and running environment such as cross wind, under the vehicle motion model analysis according to that environment,
The steering reaction force Fa can be obtained.

Therefore, even if many steering reaction force maps corresponding to various conditions are not prepared as in the prior art, it is possible to change the specifications of the vehicle and tires to be given to the vehicle motion model analysis means 26 by simply changing them. It is possible to effectively simulate the steering characteristics of the power steering under the condition of, and it is very easy to change the simulation condition. Therefore, it is possible to easily and effectively simulate the feeling of the power steering steering characteristics, which varies depending on the vehicle type and driving conditions, on the test stand, and the time and effort required for the actual vehicle test are greatly reduced. It is possible to reduce the test cost.

In particular, if the specifications of the vehicle when the vehicle motion model is analyzed are arbitrarily changed and the virtual valve characteristic Vt is arbitrarily changed as described above, the power steering device 10 ( The power steering steering characteristics under various conditions can be simulated without changing the control valve 12 and the power cylinder 13). Specifically, when the power steering pressure with respect to the steering torque T is changed, how the steering characteristic changes, and when the power steering device is mounted on another vehicle type by changing the specifications of the vehicle. It is possible to efficiently simulate how the steering characteristics change, and further how the steering characteristics change when the type of tire is changed.

Therefore, the consistency between the power steering apparatus 10 (control valve 12) and the vehicle specifications and the like can be determined without preparing a plurality of prototype devices while taking into consideration theoretical calculations of valve characteristics and specification changes based on experience. Since it is possible to simulate the steering characteristics, it is possible to significantly improve the test efficiency. The present invention is not limited to the above embodiment. For example, as a vehicle motion model analysis algorithm, various conventionally proposed methods can be used. It is also possible to directly input and set the virtual valve characteristic Vt as the correction pressure characteristic, and back-calculate the virtual valve characteristic Vt set therein from the correction pressure characteristic. Other,
The present invention can be variously modified and implemented without departing from the scope of the invention.

[0033]

As described above, according to the present invention, there is provided a power steering device including a power cylinder which is driven by switching a hydraulic circuit by the operation of a control valve driven according to a steering angle of a steering wheel, coupled to said output shaft of the power cylinder and a reaction force adding means for generating a steering reaction force to the power steering device, the steering reaction force characteristics of the power steering a power steering test device to simulate the power The steering torque T and the power steering pressure P of the steering device are measured to obtain and store a base control valve characteristic (base valve characteristic Vb) which is a reference of the power steering device.
According to a control valve characteristic (virtual valve characteristic) Vt virtually set to be realized in the power steering device and the steering torque T, steering obtained in advance according to a vehicle motion model obtained from vehicle specifications and a motion equation. Correct the steering reaction force Fa with respect to the angle θh,
Since the corrected steering reaction force F is applied to the power steering device, the steering reaction force characteristic based on the virtual valve characteristic can be applied on the power steering device with high accuracy, and the power steering steering characteristic can be efficiently simulated. It will be possible.

Further, according to the second aspect of the invention, the steering reaction force Fa with respect to the steering angle θh is obtained based on the analysis result of the vehicle motion model according to the specifications of the vehicle and the tires, the driving state, and the traveling environment. Therefore, the steering reaction force under various conditions can be efficiently set without preparing an enormous steering reaction force map, and the test efficiency can be improved.

Further, according to the third aspect of the invention, the difference ΔP between the base valve characteristic Vb and the virtual valve characteristic Vt is obtained as the correction pressure characteristic, and the steering reaction force Fa obtained based on the vehicle motion model analysis result is obtained. Since the correction is performed according to the corrected pressure characteristic, it is possible to easily and efficiently set the steering reaction force characteristic based on the virtual valve characteristic. Further, according to the invention described in claim 4, since the virtual valve characteristic Vt is arbitrarily and variably set according to the valve characteristic of the power steering device to be realized , various control valves are prototyped. It is possible to easily set the desired valve characteristic without any need to simulate the steering characteristic.

[Brief description of drawings]

FIG. 1 is a schematic block configuration diagram of a power steering test apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram showing a concept of a vehicle motion model to be analyzed.

FIG. 3 is a diagram showing a schematic flow of a simulation process according to the present invention.

[Explanation of symbols]

10 power steering device 12 control valve 13 power cylinder 18 reaction force actuator 20 control block 21 base valve characteristic acquisition means (base valve characteristic V
b) 22 virtual valve characteristic setting means (virtual valve characteristic Vt) 23 steering reaction force calculation means 24 steering reaction force correction means 25 corrected pressure characteristic calculation means 26 vehicle motion model analysis means 27 servo controller (steering reaction force characteristic)

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-4-133858 (JP, A) JP-A-4-148838 (JP, A) JP-A-4-113907 (JP, A) JP-A-4- 218746 (JP, A) JP 4-204236 (JP, A) JP 4-232829 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B62D 5/00-5 / 32 B62D 6/00-6/06 G01M 17/00-17/06

Claims (4)

(57) [Claims] 1. A power steering device including a control valve driven according to a steering angle of a steering wheel, a power cylinder driven by switching a hydraulic circuit by the operation of the control valve, and an output shaft of the power cylinder. Connected to the power steering device
Has a reaction force adding means for generating a steering reaction force, the steering reaction force characteristics of the power steering a power steering testing apparatus for simulating, by measuring the steering torque and the power steering pressure of the power steering device The characteristics of the base control valve, which is the reference of the power steering device, are obtained and
A base valve characteristic storage means for storing a over scan control valve characteristics, a virtual valve characteristic setting means for setting a virtual control valve characteristics to be realized in the power steering system, the vehicle is determined in advance by the vehicle specifications and the equation of motion comprising: a steering reaction force calculating means for calculating a steering reaction force to the steering angle in accordance with a motion model, the base valve characteristic, the virtual valve characteristic, and the steering reaction force correction means for correcting the steering reaction force according to the steering torque and, wherein in the reaction force adding means, a power steering test apparatus characterized by imparting a corrected steering reaction force at the steering reaction force correction means to the power steering system. 2. The steering reaction force calculating means obtains a steering reaction force with respect to a steering angle based on an analysis result of a vehicle motion model according to specifications of a vehicle and tires, a driving state, and a traveling environment. The power steering test device according to claim 1. 3. The steering reaction force correction means obtains a difference between the base valve characteristic and the virtual valve characteristic as a correction pressure characteristic, and a reaction force correction value obtained based on the correction pressure characteristic and the steering torque. The power steering test device according to claim 1, wherein the steering reaction force is corrected by subtracting from the steering reaction force. 4. The virtual valve characteristic setting means is realized.
The virtual valve characteristic is set according to the valve characteristic of the power steering device to be obtained.
The power steering device according to.