JPS6261814A - Vehicle characteristic controller - Google Patents

Abstract

PURPOSE:To stabilize the characteristics of a vehicle even if the value of the neutral position is incorrect by prohibiting the change of the characteristics of the vehicle when the value of the neutral position is incorrect when the result of the judgement of the correctness of the steering neutral position. CONSTITUTION:When the detection output of a steering-wheel angle sensor 1 is input into a controller 2, the value thetac of the steering neutral position is obtained according to a prescribed program in a calculation processing appara tus 7. Though the roll rigidity control, etc. for suspension apparatus 4a-4d are carried out according to a prescribed program, it is judged if the obtained value thetac of the neutral position is correct or not, and if the judgement is 'incor rect', the change of the characteristics of a car is prohibited by driving a vehicle characteristic change prohibiting means. With such constitution, the char acteristics of the car can be stabilized even if the neutral position is incorrect.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention detects the steering angle of the steering wheel of a vehicle using a steering angle sensor, and adjusts the roll stiffness of a suspension device and power steering based on the detected steering angle. The assist force of the device and the rear wheel steering angle of the four-wheel steering device are at least 1
More specifically, the present invention relates to an improvement in a vehicle characteristic control device that controls two vehicle characteristics, and more specifically, to control those vehicle characteristics by taking into account the steering angle detected by a steering angle sensor, especially the accuracy of its steering neutral position. The present invention relates to a vehicle characteristic control device.

[Conventional technology]

Conventional steering angle sensors for detecting the steering angle of steering wheels in vehicles include potentiometer type sensors that detect the rotational position as a voltage signal and sensors that detect the rotational position as a voltage signal. A photoelectric type is known that detects two voltage pulse signals that are shifted from each other.

However, with these steering angle sensors, there are manufacturing and installation errors and variations in the steering angle sensor itself, the steering wheel, and other components, and the components and their installation may deform during use. When installing a steering angle sensor, it is necessary to set the detected value to the steering neutral position of the steering wheel. It is difficult to set accurately.

Therefore, when using the above-mentioned steering angle sensor, the steering neutral position is determined by detection or calculation separately from the detected value of the steering angle sensor or based on the detected value, and the detected value of the steering angle sensor and its steering It is necessary to obtain the direction and magnitude of the steering absolute angle of the steering wheel from the difference from the neutral position.

As a conventional method of obtaining the neutral position of the detected value of these steering angle sensors, for example, the method disclosed in Japanese Patent Application Laid-Open No. 59-26341 is known.

In this method, the steering angle detected by the steering angle sensor when the vehicle is traveling stably in a straight line is used as the neutral steering position. It will be updated every time.

Another conventional method for obtaining the neutral steering position is described in Japanese Patent Application No. 1987-31872, which is an earlier application filed by the present applicant.

This method samples the steering angle detection value of the steering angle sensor every certain distance traveled by the vehicle, stores a predetermined number of these sample values, and discards the oldest steering angle detection value for each sampling, and discards the latest steering angle detection value. The detected values are stored, and the average value of a predetermined number of updated and stored steering angle detected values, that is, the moving average value of the steering angle detected values is used as the steering neutral position.

[Problem that the invention seeks to solve]

However, in the case where the steering neutral position is determined by such a method and the absolute steering angle is obtained by calculating the difference between the steering angle detection value of the steering angle sensor and the steering neutral position, the ignition switch is turned on. As long as the distance traveled after the power to the calculation unit in the steering neutral position is turned on is not large,
For example, if the vehicle is stopped with the steering wheel turned off when the power is turned on, the calculated neutral steering position value may temporarily have a large error, and the correct neutral steering position may not be accurate. The problem was that it was not represented.

Therefore, the absolute steering angle is determined from the difference between the detected steering angle value and the neutral steering position, and based on this absolute steering angle, the roll stiffness of the suspension device, the assist force of the power steering device, or the rear of the four-wheel steering device is determined. For those that control vehicle characteristics such as wheel steering angle, control of vehicle characteristics may become unstable while the neutral steering position cannot be accurately determined until the distance traveled after the power is turned on is not long. The problem was that there was a risk that this would happen.

This invention was made by focusing on such conventional problems, and even if the value of the steering neutral position is inaccurate, mainly because the distance traveled after the power is turned on is not large, the vehicle characteristics can be improved. The object of the present invention is to provide a vehicle characteristic control device that can stably control the vehicle characteristics.

[Means for solving problems]

Therefore, as shown in FIG. 1, the vehicle characteristic control device of the present invention calculates the steering angle centimeter for detecting the steering angle θ, the steering neutral position detection means for detecting the steering neutral position θc, and the steering neutral position θc. The number (of the steering neutral position calculation means)
a steering absolute angle calculating means for calculating the absolute steering angle (θ-θc) by calculating the difference between the steering angle θ and the steering neutral position θc; and a suspension device based on the steering absolute angle (θ-θc). A vehicle characteristic control device comprising a vehicle characteristic changing means for changing at least one vehicle characteristic among the roll rigidity of the vehicle, the assist force of the power steering device, and the rear wheel steering angle of the four-wheel steering device. A steering neutral position direct pressure accuracy determining means for determining accuracy, and when the value of the steering neutral position θc is inaccurate as a result of the determination by the steering neutral position accuracy determining means, the vehicle characteristics are changed by the vehicle characteristic changing means. [Operation] The operation of the vehicle characteristic control device of the present invention is such that the steering neutral position θc is determined by the steering neutral position accuracy determining means. The characteristic change prohibition means determines whether the value is accurate or not, and prevents the vehicle characteristic change operation from being performed by the vehicle characteristic change means while the steering neutral position θc is inaccurate, for example, while the distance traveled after the power is turned on is not large. To prevent unstable control of the vehicle characteristics from being performed, the vehicle characteristics are changed only after the steering neutral position θc is determined to be accurate by the steering neutral position accuracy determining means. It is something.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

In the embodiment, the steering neutral position θc is calculated from the steering angle θ detected by the steering angle sensor, and the difference between the steering angle θ and the steering neutral position θc is calculated to calculate the steering absolute angle (θ−
θc), determine the roll state of the vehicle body based on this absolute steering angle (θ−θc), and change the damping force of the variable damping force shock absorber of the suspension device according to the determination result, thereby adjusting the roll state as a vehicle characteristic. This controls rigidity and suppresses vehicle body roll.

First, the configuration will be explained. In FIG. 2, the steering angle sensor 1 is of a potentiometer type or a photoelectric type, as described at the beginning, and is sometimes difficult to install to set the steering neutral position θc.

2 is a controller, and this controller 2 includes a microcomputer 3 and a drive circuit 5 for driving an actuator for changing the damping force of variable damping force shock absorbers 4a to 4d included in the suspension system of the vehicle. It consists of:

The microcomputer 3 includes at least an ink face circuit 6, an arithmetic processing unit 7, and a storage device 8 such as a RAM or ROM, and a steering angle sensor 1 and a drive circuit 5 are connected to the interface circuit 6.

Note that the steering angle sensor l that outputs a digital quantity detection signal, such as a photoelectric type, is directly connected to the interface circuit 6, and a steering angle sensor l that outputs an analog quantity detection signal, such as a potentiometer type, is connected to the A/ It is connected to the interface circuit 6 via a D converter (not shown).

The arithmetic processing device 7 reads the steering angle θ detection signal from the steering angle sensor 1 via the interface circuit 6, and performs calculations and other processing described below based on this signal. Further, the storage device 8 stores a predetermined program necessary for executing the processing, and also stores processing results of the arithmetic processing device 7 and the like.

FIG. 3 shows an example of variable damping force shock absorbers 4a to 4d in which the damping force can be changed to two levels, a soft side and a hard side.

In the same figure, 10 indicates an upper rod 1) and a lower rod 1).
It is a piston mouth/throat configured by connecting two parts, and its upper end is fixed to the vehicle body side. 13 is a tube whose lower end is fixed to the wheel side; 14 is a piston which is fixed to the lower end of the lower rod 12 and slides along the inner circumferential surface of the tube 13; and 15 is a tube 13 fixed to the bottom side of the tube 13.
It is a free piston that slides along the inner peripheral surface of the piston. Inside the tube 13, above the piston 14 there is a piston upper chamber A, the piston 14 and a free piston 15.
A lower piston chamber B and a gas chamber C are formed below the free piston 15, respectively.The upper piston chamber A and the lower piston chamber B are filled with oil, and the gas chamber C is filled with high pressure gas. .

16 is an extension side valve, 17 is an extension side orifice, 18 is a contraction side valve, and 19 is a contraction side orifice. Also,
20 and 21 are through holes and cavities formed in the upper rod 1), and 22 and 23 are bypass paths and cavities formed in the lower loft 12.

A plunger 24 is disposed within the two cavities 21 and 23, and this plunger 24 is constantly pressed upward in the drawing (in the D direction) by the restoring force of a return spring 25. A solenoid 26 is disposed around the plunger 24. Actuator 27 with solenoid 26 and plunger 24
Configure.

The solenoid 26 is connected to the drive circuit 5 via a lead wire 28 passing through the through hole 20 of the Afvar rod 1).

In the variable damping force shock absorbers 4a to 4d, during the extension stroke, the extension side valve 16 opens and the piston upper chamber A and the piston lower chamber B communicate through the extension side orifice 17, and the compression side pulp 18 The contraction side orifice 19 is closed.

In addition, in the contraction stroke, the contraction side valve 18 opens, the piston upper chamber A and the piston lower chamber B communicate with each other via the contraction side orifice 19, and the expansion side orifice 17 is closed by the expansion side pulp 16. .

Next, the operation of this embodiment will be explained.

When the ignition switch is turned on, the controller 2 is powered on, and the detection signal from the steering angle sensor 1 is supplied to the interface circuit 6 of the microcomputer 3.

FIG. 4 shows a procedure executed in the microcomputer 3 for determining the steering neutral position θc from the detection signal of the steering angle sensor 1. This process is preferably executed as an interrupt every time a vehicle speed pulse from a vehicle speed sensor (not shown) is input, that is, every time the vehicle travels a predetermined distance Δl.

``In the same figure, in step ■, the steering angle sensor 1
Read the value of the steering angle θ from the detection signal.

When the steering angle sensor 1 is of a potentiometer type, the analog detection signal of the steering angle sensor 1 is converted into a digital signal by an A/D converter, and the digital signal becomes the steering angle θ.

When the steering angle sensor 1 is of a photoelectric type, for example, as described in Japanese Patent Application No. 59-31872, two phase-shifted pulses are input from the steering angle sensor l to the interface circuit 6. For example, at the rising edge of the signal, the main program is interrupted and the direction of steering is determined based on the phase shift, and each time a pulse signal is input, a predetermined counter is counted up for right-hand turning, and for left-hand turning. If so, it counts down and the count value is set as the steering angle θ.

Next, in step (2), the maximum value θc of the previous steering angle θ stored in a predetermined area of the storage device 8 is read out and compared with the steering angle θ, and if θ>θ8, step (2)
θ is updated and stored as the maximum value θ8, and is not updated if θ≦θc.

Next, in step (2), the minimum value θc of the previous steering angle θ stored in a predetermined area of the storage device 8 is read out and compared with the steering angle θ, and if θ is θ1, θ is set to the minimum value in step (2). It is updated and stored as a value θc, and is not updated if θ≧θ.

Next, the process proceeds to step (2), where the absolute value of the difference between the maximum value θ8 and the minimum value θc of the steering angle θ updated and stored as described above is determined, and this value is compared with a predetermined value Δθ. do. If Δθ is 1θ8−θ1), step ■
Then, ΔE is added to the value of a predetermined counter 1 for accumulating the traveling distance 1, and the process goes to step 2.

In step (2), a comparison is made to see if the travel distance i, which is the content of the counter l, is greater than or equal to a predetermined distance, and 1<L
If so, return to the main program. Note that the predetermined distance may be initially set to a value set by initialization, and then reset in step (2) to be described later.

If l is greater than or equal to step (2), then in step (2), the maximum value θ8 and the minimum value θc are averaged, and this is set as the steering neutral position θc. The program then resets the distance traveled to i, which is the content of , and returns to the main program.

At step ■, 1θc-θ1! If ≧Δθ, then
Move to step [phase] and reach maximum value θ8. Clear the minimum value θc and the travel distance 2, and return to the main program.

According to such processing shown in FIG. 4, the steering angle sensor 1
The steering neutral position θc is defined as the average value of the maximum value θ and the minimum value θc of the detected values of the steering angle θ.However, the difference between the maximum value θ4 and the minimum value θc is a predetermined small value. Only when straight running within the range (-8θ to Δθ) continues for a predetermined distance or more, the steering becomes neutral based on the average value of the maximum value θc and the minimum value θc during that travel distance. A position θc is calculated. and,
The difference between the maximum value θc and the minimum value θc is within a predetermined range (-Δθ to Δθ
), and even if the difference is within a predetermined range, the calculation of the steering neutral position θc is not executed while the travel distance within the range is less than the predetermined distance.

Next, a case in which the roll rigidity of the suspension system is controlled based on the steering neutral position θc determined in this manner will be described with reference to FIG. 5. This process is preferably executed as a timer interrupt every 20 tatami mats, for example.

In FIG. 5, first in step @, it is determined whether the value of the steering neutral position θc in the process shown in FIG. 4 is accurate. This determination is made when the steering neutral position θc is calculated in step [phase] of FIG.
The difference between the maximum value θ and the minimum value θc of the steering angle θ is within a predetermined range (-
Δθ ~ Δθ) If straight running continues for a predetermined distance or more, the steering neutral position θc is determined as the average value of the maximum value θN and the minimum value θ1 during that travel distance. The value of is determined to be accurate.

Note that in step (2), the predetermined travel distance is reset to the travel path M1 of the counter β, so that the steering neutral position θc is not calculated thereafter unless the newly set predetermined travel distance is exceeded. Therefore, since the calculation is not performed unless the conditions require a more accurate neutral steering position θc, a more accurate neutral steering position θc can be obtained as the vehicle travels.

Then, in the process shown in FIG. 4, the steering neutral position θc
is not calculated, that is, while the difference between the maximum value θ8 and the minimum value θc is not within the predetermined range (-Δθ to Δθ), and even if the difference is within the predetermined range, the difference is within the predetermined range (-Δθ to Δθ). While the distance is less than a predetermined distance, it is determined that the value of the steering neutral position θc is not accurate even if it is calculated.

In step 0, if it is determined that the value of the steering neutral position θc is accurate, the roll stiffness of the suspension device is controlled using this steering neutral position θc. That is, the process moves to step 0, and the difference between the value of the steering angle θ detected by the steering angle sensor 1 and the value of the steering neutral position θc calculated as described above is calculated to obtain the steering absolute angle (θ−
θc) is determined, and it is checked whether this absolute steering angle (θ−θc) is within a predetermined range (−a−a).

That is, if 1θ-θc lea, it is determined that the vehicle body is not rolling at all or that much, and the damping force of the variable damping force shock absorbers 4a to 4d is set to the soft side, and the roll rigidity of the vehicle body is set to the soft side. .

When setting the damping force of the variable damping force shock absorbers 4a to 4d to the soft side, a control signal of ``rL (low level, or logical value "0")'' is supplied from the interface circuit 6 of the microcomputer 3 to the drive circuit 5. do. 2 and 3, no excitation current is supplied from the drive circuit 5 to the solenoid 26 of the actuator 27, so the solenoid 26 becomes de-energized, and the plunger 24 is moved by the restoring force of the return spring 25. The lower end of the plunger 24 is pushed upward (in the D direction), and the lower end of the plunger 24 is removed from the bypass passage 22, and the upper piston chamber and the lower piston chamber B are brought into communication via the bypass passage 22. Therefore, the variable damping force shock absorbers 4a to 4d The damping force is set to the soft side. Therefore, the roll stiffness of the vehicle body is on the soft side.

Returning to FIG. 5, if 1θ-θc1≧a at step 0, it is determined that the vehicle body is rolling significantly, and the damping force of the variable damping force shock absorbers 4a to 4d is switched to the hard side, thereby causing the vehicle body to roll. Switch the rigidity to the hard side to suppress vehicle body roll.

When switching the damping force of the variable damping force shock absorbers 4a to 4d to the hard side, a control signal of ``rH (high level, or logical value "1")'' is supplied from the interface circuit 6 of the microcomputer 3 to the drive circuit 5. . In this way, in FIGS. 2 and 3, a predetermined value of excitation Mit is applied from the drive circuit 5 to the solenoid 26 of the actuator 27.
When the flow is supplied, the solenoid 26 becomes excited, and the electromagnetic force of the solenoid 26 causes the plunger 24 to move downward in the drawing (in the E direction) against the restoring force of the return spring 25.
, the lower end of the plunger 24 enters the bypass passage 22, and the communication between the piston upper chamber A and the piston lower chamber B is cut off. Therefore, the damping force of the variable damping force shock absorbers 4a to 4d changes to the hard side. is set to Therefore, the roll stiffness of the vehicle body is on the hard side, and roll of the vehicle body is suppressed.

Returning to FIG. 5, if it is determined in step [phase] that the value of the steering neutral position θc is inaccurate, control of the roll stiffness of the suspension device in steps 0 to ■ is prohibited, and step [phase] is determined to be inaccurate. ], the damping force of the variable damping force shock absorbers 4a to 4d is fixed to the soft side,
Fix the roll rigidity to the soft side.

The operation of fixing the damping force of the variable damping force shock absorbers 4a to 4d to the soft side is the same as the case of setting the damping force to the soft side described above, and maintains the stiff state.

After controlling the roll rigidity in steps @ to [phase], proceed to step O, and perform other controls not based on the detected value of the steering angle sensor 1, such as suppressing the nose dive of the vehicle body during brake stitching. Therefore, anti-dive control is performed to switch the damping force of the variable damping force shock absorbers 4a to 4d to the hard side.

FIG. 6 shows a specific example of the roll rigidity control described above,
At time t when the ignition switch is turned on, the steering wheel turns sharply to the left and the vehicle is stopped, and the neutral steering position θc is significantly deviated. It shows distance.

In the figure, when the vehicle starts running from time t0,
The steering wheel returns to the neutral position and the steering angle θ
The detected value changes to the right.

During mileage 1), the maximum value θ8 and minimum value θc of the steering angle θ
is within a predetermined range, that is, 1θ8−θc1<
Δθ, and 1θc−θc1≧Δθ at the end of step 1), but since lI is less than the predetermined distance, the value of the steering neutral position θc is not calculated. Similarly, during the traveling distance 12, lθ7−θc1<Δθ, and 1 at the end point t1 of lt.
θc−θc1≧Δθ, but in this case l! Since ≧L, the value of the steering neutral position θc is calculated from time t onward and is accurate. Therefore, in this invention, the time points t0 to 1. In this case, the damping force is fixed to the soft side and roll rigidity control is prohibited, and from time t1 onwards, the steering absolute angle (θ-〇) is the difference between the detected steering angle θ value and the calculated value of the steering neutral position θc.

) is compared with a predetermined value a to control the damping force, that is, the roll stiffness.

Conventionally, at mileage distances of 13 and 7!4, 1θ-θc1
Since ≧a, the damping force was unnecessarily switched to the hard side in 13 and E4, and the roll rigidity was switched to the hard side, so there was a risk that the roll characteristics of the vehicle would become unstable during this time. be.

FIG. 7 shows another embodiment of roll stiffness control.

In this embodiment, in step O, the steering neutral position θc
If it is determined that the value of is inaccurate, the process of fixing the damping force to the soft side as shown in FIG. 5 is not performed, and the process moves to step O to immediately execute anti-dive control.

In the embodiment described above, regarding the various means shown in FIG. 1, the process shown in FIG. 4 is a specific example of the steering neutral position and position calculation means, and the process of step ◎ in FIGS. A specific example of the steering absolute angle calculation means is shown in step @ of FIGS. A specific example of the characteristic changing means using the drive circuit 5 in FIG. 2 and the actuator 27 in FIG. 3 is transferred to step O after the process of step [phase] in FIG. The processing to be performed is a specific example of the characteristic change prohibition means.

In addition, although the configuration using a microcomputer as a controller is shown, instead of this, a comparison circuit, an addition circuit, a subtraction circuit, an absolute value circuit, a command value setting circuit,
It is also possible to configure the controller by combining electronic circuits such as counting circuits and logic circuits.

Further, the calculation method or detection method of the steering neutral position θc is not particularly limited, and as explained in the embodiment, the difference between the maximum value θ7 and the minimum value θc of the detected value of the steering angle θ is within a predetermined range (- In addition to setting the steering neutral position θc as the average value of the maximum value θc and minimum value θc when traveling within Δθ to Δθ continues for a predetermined distance or more, the steering is performed using the moving average of the detected value of the steering angle sensor 1. The neutral position θc may be used.

In this case, the means for determining whether the value of the neutral steering position θc is accurate is that the value of the neutral steering position θc determined by a moving average is usually Since there is a high probability that it will be inaccurate, the distance traveled by the vehicle after the ignition switch was turned on is detected, and as long as this distance traveled is less than a predetermined distance, the value of the determined neutral steering position θc is is inaccurate, and it is preferable to determine that it is accurate after a predetermined distance has been exceeded.

In addition, in the case of the above-mentioned embodiment as well, the predetermined path ji
Since the value of the steering neutral position θc is not calculated unless the vehicle travels more than LLL, it can be said that the embodiment is also a type of means for determining whether or not the vehicle has traveled more than a predetermined distance.

In addition, although the damping force of the shock absorber can be changed to two stages, soft side and hard side, in order to perform roll control, the number of change stages is not limited to two stages.
The present invention can also be applied to products that can be changed in three or four or more stages of soft, medium, and hard, and in that case, two of the multiple stages can be changed as appropriate.
The invention is applied to the steps.

In addition, in order to control roll stiffness, the case where the damping force of the shock absorber is changed is illustrated, but instead of this damping force of the shock absorber, or together with the damping force of the shock absorber, the spring constant of the fluid suspension device is changed. This invention also includes a case where the roll stiffness is controlled by doing so.

Furthermore, the present invention is not limited to controlling roll stiffness as a vehicle characteristic, but is applicable to all control of vehicle characteristics using detected values of a steering angle sensor.
In addition to controlling the roll stiffness of the suspension device illustrated,
For example, for a power steering device that controls the assist force based on the steering angle θ and the steering force detected by a steering angle sensor, and for a four-wheel steering device that controls the rear wheel steering angle to an angle proportional to the steering angle θ. This invention can also be applied to.

〔Effect of the invention〕

As explained above, according to the vehicle characteristic control device of the present invention, it is determined whether or not the steering neutral position detected or calculated based on the steering angle detection value by the steering angle sensor is accurate, and the steering neutral position is When the value of is determined to be incorrect,
The configuration prohibits changes in at least one of the vehicle characteristics among the roll rigidity of the suspension device, the assist force of the power steering device, and the rear wheel steering angle of the four-wheel steering device, so for example, when driving after the power is turned on, Even if the value of the detected or calculated neutral steering position is inaccurate, such as when the distance is not large, unstable control operations of the vehicle characteristics based on the inaccurate value of the neutral steering position can be prevented, and the vehicle characteristics can be improved. The effect is that it is possible to control stably.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the basic configuration of a vehicle characteristic control device according to the present invention, FIG. 2 is a block diagram showing the configuration of an embodiment of the present invention, and FIG. 3 is a longitudinal section showing an example of a variable damping force shock absorber. 4 is a flowchart showing the processing procedure of an embodiment for determining the steering neutral position based on the detected value of the steering angle sensor, which is executed in a microcomputer, and FIG. 5 is based on the processing result of FIG. 4. A flowchart showing the processing procedure of an example of the control of roll stiffness of the suspension device to be performed, FIG. 6 is a diagram for explaining a specific example of the processing operation of FIG. 5, and FIG. 7 is a flowchart showing the control of roll stiffness of the suspension device. 12 is a flowchart showing a processing procedure of another embodiment. l... Steering angle sensor, 2... Controller, 3...
- Microcomputer, 4a to 4d... Variable damping force shock absorber, 5... Drive circuit, 6... Interface circuit, 7... Arithmetic processing unit, 8... Storage device, 10... Piston Lower chamber do, 13... tube, 14... piston, 22... bypass path, 24...
... Plunger, 25 ... Return spring, 26
... Solenoid, 27... Actuator, A...
- Piston upper chamber, B... Piston lower chamber, θ... Steering angle, θc... Steering neutral position, θ-θc... Steering absolute angle. Figure 1 Figure 3 @ Figure 4

Claims (2)

[Claims] (1) A steering angle sensor that detects the steering angle θ, at least one of a steering neutral position detection means that detects the steering neutral position θ_c, and a steering neutral position calculation means that calculates the steering neutral position θ_c, and the steering angle θ and the steering neutral position θ_c
a steering absolute angle calculating means for calculating the absolute steering angle (θ-θ_c) by calculating the difference between and a vehicle characteristic changing means for changing at least one vehicle characteristic of a rear wheel steering angle of a wheel steering device, wherein the steering neutral position accuracy determination determines the accuracy of the steering neutral position θ_c. and when the value of the steering neutral position θ_c is inaccurate as a result of the determination by the steering neutral position accuracy determining means,
A vehicle characteristic control device comprising: characteristic change prohibiting means for prohibiting the vehicle characteristic changing operation by the vehicle characteristic changing means. (2) The steering neutral position accuracy determination means determines the accuracy of the steering neutral position based on whether the vehicle has traveled a predetermined distance or more after the power of the vehicle characteristic control device is turned on. A vehicle characteristic control device according to claim 1.