KR20080088052A - Device for detecting different kinds of tires in esp and method thereof - Google Patents

Abstract

A device for detecting different kinds of tires in an ESP(Electronic Stability Program) system and a detecting method suitable for the same are provided to improve stability of a vehicle by checking whether different kinds of tires are installed or not, regardless of the turning state of the vehicle and distortion of the slip ratio. A device for detecting different kinds of tires in an ESP system is composed of: an ESP sensor signal processing unit judging the state of a vehicle speed sensor, a wheel speed sensor, a steering angle sensor, a lateral acceleration sensor, and a yaw rate sensor and setting offset; a tire slip ratio calculation unit computing the slip ratios of each tire by vehicle speed and wheel speed of signals sent from the vehicle and wheel speed sensors; an effective slip judging unit judging whether the tire slip ratio is generated by the control of driving power and braking power of a vehicle or not, by exchanging information with an ABS(Anti-Lock Brake System), a TCS(Traction Control System), or an ESP; a turning judging unit judging whether the vehicle turns or not, from signals transmitted from the steering angle sensor, the lateral acceleration sensor, and the yaw rate sensor; and a different tire judging unit determining that different kinds of tires are installed, if a difference value between the slip ratios of tires of inner and outer races of the predetermined speed is kept within a predetermined range for a certain time while the slip ratio of each tire is in an effective state, but not the distortion state generated by the control of driving power and turning condition.

Description

Heterogeneous tire detection device and suitable detection method for vehicle stability control system {device for detecting different kinds of tires in ESP and method

1 is a block diagram showing a control unit for heterogeneous tire detection of a vehicle stability control system according to the present invention;

2 is a flowchart illustrating a hetero tire detection method of a vehicle stability control system according to the present invention;

FIG. 3 is a graph illustrating different tire determination criteria according to slip ratios of inside and outside wheels of FIG. 2; FIG.

The present invention relates to a hetero-tire detection device of a vehicle stability control system and a detection method suitable thereto, and more particularly, to a difference in the rotational speed of a left wheel and a right wheel in an stability control device (ESP) installed to improve driving stability of a vehicle. The present invention relates to a hetero-tire detecting apparatus of a vehicle stability control system capable of preventing malfunctions when turning a vehicle due to detecting heterogeneous tires, and a sensing method suitable thereto.

In general, automobiles are equipped with various devices for improving driving stability and braking stability of the vehicle.Anti-Lock Brake System (ABS) and Action Control System (TCS) to prevent slippage of the wheel, and vehicle attitude ESP (Electronic Stability Program) and suspension damping device CDC (Continuous Damping Control), steering device ESP (Electric Power Steering) and the like is mounted.

That is, various electronic control devices related to braking, steering, and suspension of the vehicle are installed to allow the vehicle to run more stably.

The ESP device is for securing stability while driving the vehicle. The ESP device receives a signal of a vehicle state transmitted from a vehicle speed sensor, a wheel speed sensor, a yaw rate sensor, a steering angle sensor, a brake pressure sensor, a lateral acceleration sensor, and the like. The controller is configured to control the wheel cylinder and EMS (Engine Management System) with the ESP controller.

Referring to FIG. 3, the operation of the ESP device is obtained from the wheel speed sensor, the steering angle sensor, the yaw rate sensor, the brake pressure sensor, and the like, and the measured values for the vehicle speed, the steering angle, the turning speed, the lateral acceleration, and the brake pressure.

In addition, the road surface friction coefficient, which is a value which cannot be obtained directly from the sensor, and the body slip angle are calculated and calculated by the ECU, and the actual motion of the vehicle is estimated based on the above values.

In addition, the motion characteristics of the vehicle desired by the driver are calculated through the kinematic analysis according to the obtained values.

After analyzing the actual motion characteristics and the dynamic motion characteristics of the vehicle, the two values are compared to determine whether the current vehicle state is excessive understeer state (PLOW) or excessive oversteer state (SPIN OUT).

For example, in the case of excessive understeer, the front wheel reaches the limit of adhesion between the tire and the road, and the rear wheel is controlled to compensate for the movement trajectory of the vehicle. It will keep the state stable.

Here, if some of the tires of the vehicle are not prescribed tires and are equipped with heterogeneous tires with reduced weight or reduced width, ESP cannot be properly controlled by distorting the cornering force during turning of the vehicle. The device detects whether or not different tires are mounted.

That is, when the difference in the left and right tire rotation speed transmitted from the wheel speed sensor is exceeded by a predetermined range or more and the time exceeded for a predetermined time, it is determined that different tires are mounted and appropriately controlled. .

However, if the heterogeneous tire is detected by the difference in the left and right tire rotation speed as described above, the difference in the rotational speed of the front and rear or left and right tires generated when the vehicle is turning can be determined by distinguishing the speed difference when the heterogeneous tire is mounted. By not being able to do this, there is a problem that the judgment of whether or not the heterogeneous tire is mounted is substantially inaccurate.

Accordingly, an object of the present invention is to solve the above problems, and to more accurately improve the vehicle stability by accurately determining whether or not different tires are mounted regardless of the difference in the rotational speed of the front, rear, left, and right tires generated when the vehicle is turning. It is to provide a hetero-tire detection device and a detection method suitable for the vehicle stability control system that can be.

In order to realize the above object, the present invention provides an ESP sensor signal processing unit for setting whether the vehicle speed sensor, the wheel speed sensor, the steering angle sensor, the lateral acceleration sensor, the yaw rate sensor are in a normal state and the offset, and the vehicle speed sensor and the wheel speed. A tire slip ratio calculation unit that calculates the slip ratio of each tire based on the vehicle speed and the wheel speed based on the signal from the sensor, and whether the tire slip ratio is generated by the driving force or the braking force control of the vehicle and the ABS, TCS, ESP, etc. An effective slip determination unit for determining whether the vehicle is valid by exchanging information; a turning determination unit for determining whether the vehicle is currently turning from signals from the steering angle sensor, the lateral acceleration sensor, and the yaw rate sensor; The difference between the inner and outer tire slip ratios of the predetermined vehicle speed is within a certain range in a valid state other than the distortion state caused by the turning condition and the driving force control. When standing maintained for a predetermined time characterized in that constituted by two kinds of Thai judgment for judging the mounted two kinds of tires.

In addition, in the method according to the present invention, when a signal is input from each sensor installed in the ESP, ABS, etc. of the vehicle, the slip ratio calculating unit calculates the slip ratio of each tire according to the current vehicle speed and the wheel speed and passes through the low frequency filter. Obtaining a final slip rate,

Determining the validity by determining whether the final slip ratio is determined by the effective slip determination unit to determine whether the final slip ratio is not a distorted value according to driving and braking force control of the vehicle;

When the final slip ratio is calculated, determining whether the vehicle is currently turning by the turning determiner according to the steering angle, steering angle speed, lateral acceleration, and yaw rate;

Determining whether the tire is heterogeneous by the heterogeneous tire determination unit when the vehicle is in the straight state by the turning determination unit, and determining the heterogeneous tire by the heterogeneous tire determination unit;

When it is determined that the vehicle turning determination unit is in a straight state, the heterogeneous tire determination unit is characterized in that it comprises a step of determining that the heterogeneous tire is installed if the left and right slip ratio difference is maintained for a predetermined time under a certain vehicle speed or more.

1 is a block diagram illustrating a control unit for heterogeneous tire detection of a vehicle stability control system according to the present invention, wherein the vehicle speed sensor, wheel speed sensor, steering angle sensor, lateral acceleration sensor, yaw rate sensor are in a normal state and offset (OFFSET). ESP sensor signal processing unit for setting a), a tire slip ratio calculating unit for calculating the slip ratio of each tire through the vehicle speed and the wheel speed in the signals from the vehicle speed sensor and the wheel speed sensor, and the tire slip ratio An effective slip determination unit for exchanging information with ABS, TCS, ESP, etc., whether it is generated by driving force or braking force control, and determining whether it is an effective condition, and the current vehicle from the signals from the steering angle sensor, the lateral acceleration sensor, and the yaw rate sensor. The turning judging section for judging whether or not the turning is performed, and the slip ratio of each tire described above is not in a distorted state due to turning conditions and driving force control. It is composed of a heterogeneous tire determination unit that judges that it is equipped with heterogeneous tires when the predetermined range and time are satisfied.

In addition, the ABS determination unit is provided with an ABS determination unit for receiving and referring to the result of determining whether the tire is heterogeneous.

The ESP sensor signal processor detects overlapping signals from the steering angle sensor, the lateral acceleration sensor, and the yaw rate sensor to determine the validity of each sensor and to determine the steady state offset of each sensor when the vehicle goes straight.

That is, by comparing the overlapping signals among the signals from each sensor to determine the validity of each sensor, and detecting the signal value when the vehicle is going straight to detect whether the offset is normal.

Referring to Figure 2 illustrates the effects of the present invention as described above, when a signal is input from each sensor installed in a device such as ESP, ABS, etc. of the vehicle, the slip ratio calculation unit is a tire according to the following equation (1) The final slip rate is calculated according to Equation 2 below, which calculates a slip rate of the noise filter and removes noise using a low frequency filter.

[Equation 1]

lam: slip rate

w_vel (k): Wheel speed

v_ref (k): current vehicle speed

[Equation 2]

lam_w (k): final slip rate

k1: constant between 0 and 100

When the final slip rate is calculated in the slip rate calculation unit, the effective slip determination unit determines whether it is a distorted value according to the control of the driving force and the braking force to determine the validity, which is transmitted from each device such as ABS, ESP, and TCS. This is determined according to the vehicle information (whether it is in a braking state or an acceleration state or whether each device is in operation).

That is, if it is determined whether a sudden driving or braking state is performed during the operation of each device, it is determined that the slip ratio is distorted and does not determine the normal slip ratio state.

If it is not determined that the distortion state, the vehicle turning determination unit determines whether to turn according to the size of the steering angle, the steering angle speed, the lateral acceleration and the yaw rate. If it is judged and more than that, it is judged as a turn.

That is, if the steering angle is <k2, the steering angle speed is <k3, the lateral acceleration is <k4 and the yaw rate is <k5, it is judged to be straight ahead. Will be judged.

When the vehicle turning determination unit determines whether the vehicle is currently turning and determines to go straight, the heterogeneous tire determination unit determines whether or not the heterogeneous tire is installed. The judgment is made according to the graph shown.

That is, if the difference between the left and right slip ratios S1 and S2 is maintained for the time T until the speed of the vehicle V2 under the condition of the vehicle speed V1 or more, it is determined that the tire is mounted differently, and if it is maintained for the time T or less, it is determined that the normal tire is installed. do.

Of course, the determination of whether the heterogeneous tire is mounted is determined by referring to the determination of the heterogeneous tire in the information transmitted from the ABS device, and when it is determined that the heterogeneous tire is mounted, the control of the ESP is appropriately performed.

As described above, the present invention is capable of accurately determining whether or not different tires are mounted regardless of whether the vehicle is turned or not and the distortion of the slip ratio, thereby improving the vehicle stability by the vehicle stability control system.

Claims (3)

ESP sensor signal processing unit for setting the normal state and offset of the vehicle speed sensor, wheel speed sensor, steering angle sensor, lateral acceleration sensor, yaw rate sensor, and the vehicle speed and wheel speed in the signals from the vehicle speed sensor and the wheel speed sensor Tire slip ratio calculating section for calculating the slip ratio of each tire, and the effective slip which determines whether the tire slip ratio is an effective condition by exchanging information with ABS, TCS, ESP or the like to determine whether the tire slip ratio is generated by the driving force or braking force control of the vehicle. The judging section, a turning judging section for judging whether the vehicle is currently turning from the signals from the steering angle sensor, the lateral acceleration sensor, and the yaw rate sensor, and the slip ratio of each of the tires is distorted due to turning conditions and driving force control. If the difference value of the inner and outer tire slip ratio of the predetermined vehicle speed is kept within a certain range in a valid state, the heterogeneous tire is installed. Thai two kinds of sensors in the vehicle stability control system characterized in that it constituted by two kinds of judgment for judging a Thai. When a signal is input from each sensor installed in the ESP, ABS, etc. of the vehicle, the slip rate calculation unit calculates the slip rate of each tire according to the current vehicle speed and the wheel speed, and passes through the low frequency filter to obtain the final slip rate; Determining the validity by determining from the effective slip determination unit whether the final slip ratio is obtained as a distorted value according to the driving force and the braking force control of the vehicle; When the final slip ratio is calculated, determining whether the vehicle is currently turning by the turning determiner according to the magnitude of the steering angle, the steering angle speed, the lateral acceleration, and the yaw rate; Determining whether the tire is heterogeneous by the heterogeneous tire determination unit when the vehicle is in the straight state by the turning determination unit, and determining the heterogeneous tire by the heterogeneous tire determination unit; When the vehicle turning determination unit is determined to go straight, the vehicle stability control comprising the step of judging that the heterogeneous tire is installed when the difference in the left and right slip ratio is maintained for a predetermined time in a condition of the difference tire constant speed or more. Different tire detection method of system. The method of claim 2, The hetero tire detection method of the vehicle stability control system, characterized in that the slip ratio of the vehicle is obtained according to the following equation.

lam: slip rate w_vel (k): Wheel speed v_ref (k): current vehicle speed

lam_w (k): final slip rate k1: constant between 0 and 100

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