KR100309146B1 - Method for controlling active roll stabilizer - Google Patents

Abstract

PURPOSE: A method for controlling an active roll stabilizer is provided to minimize an error due to the state of a vehicle by compensating a duty for controlling a roll angle. CONSTITUTION: A method for controlling an active roll stabilizer comprises the steps of deciding if a vehicle is in the normal state by detecting a steering angle, a vehicle speed and the pressure applied to an actuator(S20), operating a desired pressure after initializing a timer if the vehicle is not in the normal state(S40), outputting a duty signal by operating a duty using a desired pressure and a real pressure(S80), comparing the counted time to a reference time if the vehicle is in the normal state(S50), operating a desire pressure if the counted time is over the reference time(S60), compensating a feed-forth gain by using the desired pressure and the real pressure(S70), and outputting a duty signal by operating a duty using the compensated feed-forth gain(S80).

Description

Active roll stabilizer control method

The present invention relates to an active roll stabilizer device for preventing rolling of a vehicle, and more particularly, a duty for controlling a roll angle according to a vehicle state by adding or subtracting a constant gain to or from a difference between the calculated pressure and the actual pressure. The present invention relates to an active roll stabilizer control method for minimizing errors.

In the conventional active roll stabilizer control method, as shown in FIG. 1, the controller 40 calculates a desired pressure based on the vehicle speed and steering angle detected from the vehicle speed sensor 10 and the steering angle sensor 20, and measures the pressure in the pressure gauge 30. The duty was calculated by giving a constant gain to the difference of the actual pressure, and then the direction control valve 50 and the pressure control valve 60 were controlled accordingly.

In the conventional method as described above, there is a problem in that a steady state error occurs because the proportional gain is fixed according to the vehicle state such as the number of passengers or the pump output.

The present invention has been made to solve such a problem, and its purpose is to multiply the difference between the calculated pressure and the actual pressure by a constant gain to add or subtract the feed-forward gain to obtain the steady state error of the desired pressure and the actual actuator pressure. Minimize.

In order to achieve the above object, the present invention, by setting the initial value of the steering angle and the vehicle speed, and then detecting the steering angle and vehicle speed, the pressure applied to the actuator to determine whether the vehicle is in a normal state, Initializing the time and then calculating a desired pressure; calculating a duty by using the desired pressure and the detected actual pressure calculated in the step; and outputting a duty signal accordingly; Comparing the counted time with the reference time when the vehicle is in a normal state, and calculating a desired pressure when the counted time is greater than or equal to the reference time; Compensating the feed-forward gain using the desired pressure and the actual pressure detected The feedback compensation in step - by using the Four odd gain operation of the duty is characterized in that it comprises a step of outputting a signal according to the duty.

1 is a block diagram showing a roll angle control device for an active roll stabilizer.

2 is an operation flowchart showing the active roll stabilizer control method of the present invention.

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

As can be seen in FIG. 1, the roll angle controller for the active roll stabilizer includes a vehicle speed sensor 10, a steering angle sensor 20, a pressure gauge 30, a controller 40, a direction control valve 50, and a pressure control valve. It consists of 60.

The vehicle speed sensor 10 detects the speed of the vehicle while the vehicle is driving and outputs a predetermined signal accordingly.

The steering angle sensor 20 detects a turning radius of the steering wheel by the driver while the vehicle is driving and outputs a predetermined signal accordingly.

The pressure gauge 30 detects the duty pressure supplied to the actuator 70 to prevent rolling while the vehicle is running and outputs a predetermined signal accordingly.

The controller 40 calculates a desired pressure according to the vehicle speed and the steering angle detected by the vehicle speed sensor 10 and the steering angle sensor 20, and then calculates a duty according to the vehicle state by the signal of the pressure gauge 30. Output a predetermined signal.

The direction control valve 50 operates according to the signal of the controller 40 and selects a direction for applying a duty pressure.

The pressure control valve 60 operates according to the signal of the controller 40 to control the duty pressure supplied to the actuator 70 together with the direction control valve 50 by the duty value calculated by the controller 40. do.

That is, the pressure control valve 60 controls the rotational force by adjusting the pressure of the actuator 70 by the pressure provided from the hydraulic pump 80, the direction control valve 50 controls the rotational direction of the actuator to The rotation direction is controlled according to the rolling direction.

The actuator is attached to the stabilizer bar of the conventional vehicle, and the hydraulic pump 80 is connected to the drive shaft of the conventional vehicle engine.

Referring to FIG. 2, the method for controlling the active roll stabilizer of the present invention in the roll angle control device for the active roll stabilizer configured as described above is as follows.

For reference, the parameters for controlling the system are the pulse width modulation (PWM) duty of the pressure control valve and the direction of the direction control valve. The direction is automatically determined according to the rolling direction, and the duty applied to the pressure control valve is determined by the present invention. Is controlled by the method to be controlled.

During operation of the vehicle, the controller 40 sets the current steering angle str to the previous steering angle pstr and the current vehicle speed to the previous vehicle speed pspd, and then the vehicle speed sensor 10, the steering angle sensor 20, Analyzing the signal output from the pressure gauge 30 detects the steering angle (str), the vehicle speed (sped), the pressure (pf) (S10)

Thereafter, the steering angle str and the vehicle speed spd detected in the step S10 are calculated by the following equation to determine whether the vehicle is in a normal state (S20).

(pstr-str) <constant 1

(pspd-spd) <constant 2

In step S20, the difference between the previous steering angle pstr and the current steering angle str is equal to or greater than a predetermined value 1 or the difference between the previous vehicle speed pspd and the current vehicle speed becomes greater than or equal to a predetermined value 2 so that it is not a normal state. When it is determined that the response state is initialized (S30), the desired pressure Pd is calculated using the signal detected from the vehicle speed sensor 10 and the steering angle sensor 20 in the following equation (S40).

Pd = 1.2 × str × spd × (0.0098 +0.00021 × spd)

At this time, str is a steering angle detected from the steering angle sensor 20, spd is a vehicle speed detected from the vehicle speed sensor 10.

When the desired pressure Pd is calculated from the steering angle detected in the step S40 and the vehicle speed, the controller 40 uses the actual pressure Pf detected by the pressure gauge 30 to apply a duty to the actuator 70. It calculates by the following formula (S80).

Duty = Kfn × Pd + Kp × (Pd-Pf)

Where Kfn is the compensated feed-pod gain, Kp is the feed-back gain, Pd is the desired pressure calculated in step S40 above, and Pf is the actual pressure detected in the pressure gauge 30.

When the duty is calculated in the step S80, the control unit 40 outputs a predetermined signal to operate the direction control valve 50 and the pressure control valve 60 according to the calculated duty to suppress rolling 70 ).

In step S20, the difference between the previous steering angle pstr and the current steering angle str is smaller than a predetermined value 1, and the difference between the previous vehicle speed pspd and the current vehicle speed spd is smaller than 2 for a certain time, and thus may be determined to be normal. In the case of comparing the time from the step (S10) and the reference time (S50), if the reference time or more, the desired pressure (Pd) is calculated by the following equation (S60).

Pd = 1.2 × srt × spd × (0.0098 + 0.00021 × spd)

At this time, str is a steering angle detected from the steering angle sensor 20, spd is a vehicle speed detected from the vehicle speed sensor 10.

When the desired pressure is calculated according to the steering angle and the vehicle speed detected in the step S60, the controller 40 compensates for the feed-forward gain compensated using the actual pressure Pf detected by the pressure gauge 30. ) Is calculated by the following equation (S70).

Kfn = Kfn-1 + Kc × (Pd-Pf)

In this case, Kfn is the compensated feed-pod gain, Kfn-1 is the previous feed-pod gain, and Kc is the proportional gain obtained through the experiment so that the system has the maximum response speed while showing a stable response without diverging. The calculated desired pressure, Pf, is the actual pressure detected at the pressure gauge 30.

That is, in the normal state, the proportional gain Kc appropriate to the difference between the desired pressure Pd calculated according to the steering angle and the vehicle speed and the actual pressure Pf detected by the pressure gauge 30 according to the vehicle state such as ride inwind or pump output. Multiply by to compensate for the feed-forward gain for rolling control in addition to the set feed-forward gain.

In particular, the feed-forward gain Kf can be obtained by setting Kf = 100 / Pmax if the value corresponding to the maximum value of the desired control pressure is Pmax, and the feed-back gain Kp and the appropriate proportional gain Kc. The experimental results are obtained by experimentally tuning the system to achieve the maximum response speed without showing divergence.

When the feed-forward gain Kfn compensated in the step S70 is calculated, the control unit 40 calculates the duty to be applied to the actuator 70 by using the following equation (S80).

Duty = Kfn × Pd + Kp × (Pd-Pf)

Where Kfn is the compensated feed-pod gain, Kp is the feed-back gain, Pd is the desired pressure calculated in step S60 above, and Pf is the actual pressure detected by the pressure gauge 30.

When the duty is calculated in the step S80, the control unit 40 outputs a predetermined signal to operate the direction control valve 50 and the pressure control valve 60 according to the calculated duty to suppress rolling 70 ).

If the time is smaller than the reference time in step S50, the step S10 of resetting the initial values of the steering angle str and the vehicle speed to the previous value is performed.

As such, the present invention multiplies the difference between the calculated pressure and the actual pressure and adds or subtracts the feed-forward gain, thereby minimizing the error due to the vehicle condition, and the transient response is the pressure feed-back gain. The compensated feed-forward gain can be used to improve the rolling control performance of the vehicle.

Claims (5)

A stabilizer apparatus for a vehicle, comprising: setting an initial value of a steering angle and a vehicle speed, and then determining whether the vehicle is in a normal state by detecting a steering angle, a vehicle speed, and a pressure applied to an actuator; Initializing the time when the vehicle is not in the normal state, calculating a desired pressure, calculating a duty using the calculated desired pressure and the detected actual pressure, and outputting a duty signal accordingly; Comparing the counted time with a reference time when the vehicle is in a normal state in determining whether the vehicle is in a normal state; Compensating the feed-forward gain using the desired pressure calculated in the step and the detected actual pressure; And calculating a duty by using the compensated feed-forward gain, and outputting a duty signal according to the step. The method according to claim 1, wherein the determination of the steady state in the step of determining whether the steady state is made by the following equation. (pstr-str) <constant 1 (pspd-넹) <constant 2 (However, pspd: previous vehicle speed, spd: current vehicle speed) The method according to claim 1, wherein the desired pressure in the step of calculating the desired pressure is calculated by the following equation. Pd = 1.2 × str × spd × (0.0098 +0.00021 × spd) The method according to claim 1, wherein the compensation of the feed-pod gain in the step of compensating the feed-pod gain is performed by the following equation. Kfn = Kfn-1 + Kc × (Pd-Pf) (However, Kfn: compensation feed-pod gain, Kfn-1: previous feed-pod gain, Kc: proportional gain, Pd: desired pressure, Pf: actual pressure detected) The method according to claim 1, wherein the duty calculation in the step of calculating the duty is performed by the following equation. Duty = Kfn × Pd + Kp × (Pd-Pf) (Kfn: compensated feed-forward gain, Kp: feed-back gain, Pd: desired pressure, Pf: actual pressure detected)