KR100844638B1 - Tilt angle judgment system of using acceleration sensor and method thereof - Google Patents

Abstract

The present invention relates to a tilt angle determination system using an acceleration sensor and a method thereof.

The present invention removes the noise of the acceleration sensor and estimates the acceleration of the acceleration sensor with the acceleration obtained from the wheel speed sensor, and configures an inclination angle determination system that compensates for the delay phenomenon according to the acceleration estimation, thereby inclining errors on the slope and the plain. This prevents the risk of vehicle rolling on the ramp and delays in starting.

Acceleration sensor, tilt angle, estimation module, compensation module

Description

Tilt angle judgment system of using acceleration sensor and method

1 is a block diagram of a tilt angle determination system using a conventional acceleration sensor.

2 is a measurement graph at the time of determining the conventional tilt angle.

Figure 3 is a flow chart showing a tilt angle determination method using a conventional acceleration sensor.

Figure 4 is a block diagram of a tilt angle determination system using an acceleration sensor in an embodiment of the present invention.

5 is an input / output state diagram of an estimation module according to an embodiment of the present invention.

6 is an input / output state diagram of a compensation module according to an embodiment of the present invention.

7 is a flowchart illustrating a method of determining an inclination angle using an acceleration sensor according to an embodiment of the present invention.

8 is an inclination angle measurement measurement graph when the estimation module and the compensation module are applied according to an embodiment of the present invention.

* Description of the symbols for the main parts of the drawings *

11; A conversion unit 12; Mixing

13; Convergence module unit 14; Back anti-slim logic

15; Idle stop logic 20; Estimation Module

30; Compensation module

The present invention relates to a technology for determining an inclination angle of a vehicle, and more particularly, to an inclination angle determination system and method using an acceleration sensor that can eliminate the risk of rolling and delay of the vehicle due to the recognition of an inclination error on a slope and a flat surface. It is about.

In general, when measuring the inclination angle of the vehicle by using the acceleration sensor, the measured inclination angle is very unstable, and when the vehicle is stopped, the error occurs according to the characteristics of the vehicle suspension, so the inclination angle is excluded after a certain time after the stop point. Very hard to trust

That is, as shown in FIGS. 1 and 2, the speed signal V _{v_w} measured by the acceleration sensor (not shown) of the vehicle is converted into the acceleration a _{v_w} through the conversion unit d / dt 1 and the mixing unit ( 2), when the accelerometer signal (Vs; a _{v, s} , a _g , noise) included in the speed signal (V _{v_w} ) is directly transmitted to the mixing unit (2), the conversion module unit (Conversion Module) In (3), the slope angle θ is calculated as follows.

That is, the convergence module unit 3 calculates the inclination angle θ by calculating the acceleration conversion value a _{v_w} from the collected accelerometer signals Vs (a _{v, s} , a _g , noise).

Then, the entry and release timings of the creep aid system logic 4 and the idle stop logic 5 are determined through the inclination angle θ calculated from the convergence module unit 3. You can decide.

However, the conventional inclination angle determination is a vehicle in which the acceleration "0 (zero)" is maintained because the acceleration (a _{v, s} ) measured through the inclination angle and the acceleration (a _g ) obtained through the vehicle wheel speed sensor do not exactly match. Only trusting the inclination angle after the stop, as shown in Figure 3 when the vehicle is stopped due to the suspension of the suspension can be determined after a certain time after the disadvantage has a disadvantage, accordingly the backrest prevention logic (4) and Entry and release of the idle stop logic 5 is bound to be limited.

Accordingly, the present invention has been made to solve the above-mentioned problems, and the noise of the acceleration sensor is eliminated and the acceleration of the acceleration sensor is estimated as the acceleration obtained from the wheel speed sensor, and the delay phenomenon according to the acceleration estimation is compensated for. It is an object of the present invention to provide an inclination angle determination system and a method using an acceleration sensor that prevents an inclination error on an incline and a flat surface, thereby preventing the risk of vehicle rolling and an oscillation delay on the incline.

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

4 is a block diagram of an inclination angle determination system using an acceleration sensor according to an embodiment of the present invention, FIG. 5 is an input / output state diagram of an estimation module according to an embodiment of the present invention, and FIG. 6 is a compensation module according to an embodiment of the present invention. The input / output state diagram is shown.

4 to 6, in the inclination angle determination system using the acceleration sensor according to the exemplary embodiment of the present disclosure, a speed signal measured from an acceleration sensor (not shown) of the vehicle is mixed through the conversion unit 11. When the speed signal is directly transmitted to the mixing unit 12, the convergence module unit 13 calculates the inclination angle θ, and then the backplate anti-rolling logic 14 and the idle stop logic ( In constructing the inclination angle determination system to output 15),

An estimation module 20 for removing noise of the acceleration sensor and estimating the acceleration of the acceleration sensor as an acceleration obtained from a wheel speed sensor; And,

A compensation module 30 for compensating for a delay phenomenon according to the acceleration estimation; Characterized in that further comprises a.

7 is a flowchart illustrating a method of determining an inclination angle implemented by an inclination angle determination system according to an embodiment of the present invention.

Collecting the speed V _{v_w} from the wheel speed sensor;

_Converting the collected speed V _{v_w} into an acceleration a _{v_w} ;

The transformed range of the acceleration _{(a v_w) (a v_w <} 0), and the wheel after determining the range (5kph <V _{v_w} <10kph) of the speed (V _{v_w)} collected from the speed sensor accelerometer signal (Vs; a _{v, s} , a _g , noise);

=a_v,s,a_g)를 추정하며, 속하면 가속도 추정에 따른 지연 현상을 보상한 후 가속도(

=a_v,s,a_g)를 추정하는 단계;If the determination result does not belong to the range (a _{v_w} <0) of the acceleration (a _{v_w} ) and the range (5 kph <V _{v_w} <10 kph) of the speed (V _{v_w} ) collected from the wheel speed sensor, noise is removed from the collected accelerometer signal. Acceleration sensor obtained from the wheel speed sensor

= a _{v, s} , a _g ) and if they belong, compensate for the delay caused by the acceleration

estimating = a _{v, s} , a _g );

Performing an operation of subtracting an acceleration conversion value (a _{v_w} ) from the estimated acceleration (Vs; a _{v, s} , a _g , noise);

Calculating an inclination angle from the subtraction; And,

Determining the entry and exit points of the backrest prevention logic (14) and the idle stop logic (15) from the calculated inclination angle; It includes.

That is, the inclination angle determination system according to an embodiment of the present invention is an additional configuration of the estimation module 20 and the compensation module 30, the estimation module 20 is designed through a system identification method, neural network, fuzzy logic, etc. This is an ARX (Auto Regressive model with Xgenous input) model, the general model equation for ARX,

ego,

Model coefficients of the ARX using training data through the actual vehicle test,

,

The result of the training is as shown in the following equation and Table 1,

  y

  a1 = 0.9969  u1   Vs   b11 = 0.00847   b21 = -0.00536  u2 a _{v, w}   b21 = 0.1257   b22 = -0.1257

appear.

At this time, the estimation module 20 designed as described above has a stable eigenvalue of a given system for a given input signal, while having a significant delay for a given input as can be seen from the magnitude of the coefficient, thereby improving the delay characteristic. In the present invention, a separate compensation module 30 is applied.

That is, the compensation module 30 performs a function of eliminating the delay phenomenon that the estimation module 20 may have, and for this purpose, the wheel speed sensor output speed V _{v, w} and acceleration conversion values a _{v, w} In the state of receiving a), and outputs a flag (Flag) for determining the time point for updating the output of the estimation module 20,

)을 현재의 가속도 센서 출력값(

)으로 치환하는 시점을 결정하고 치환 기능을 수행하는 한편, 상기 치환 시점에 현재의 추정모듈 출력값(

)을 현재 가속도 센서값(

)에 근접시켜 실제 경사각에 가까운 값을 아래의 수학식과 같이 산출하게 되는 것이다.In the design of the compensation module 30 to compensate for the delay phenomenon of the ARX model used as the estimation module, the output value before the step of the estimation module 20 (

) Is the current acceleration sensor output value (

Determine a time point for substituting a) and perform a substitution function, and at the time of the substitution time, the current estimated module output value (

) Is the current acceleration sensor value (

) To calculate the value close to the actual tilt angle as shown in the following equation.

In this case, when the compensation time point made by the compensation module 30 passes, the estimation module 20 outputs an estimated value as an original function again, which reduces the estimation delay of the actual inclination when the slope changes. For sake.

Therefore, when the design of the estimation module 20 and the compensation module 30 is completed as described above, the operation of the state applied to the tilt angle determination system will be described.

First, when the wheel speed sensor of the vehicle (not _shown ) collects the speed V _{v_w} , the collected speed V _{v_w} is output to the converter 11 and the mixer 12, respectively.

Then, the conversion unit 11 converts the speed V _{v_w} collected by the wheel speed sensor into acceleration (a _{v_w} ) and outputs it to the estimation module 20. The accelerometer signals Vs (a _{v, s} , a _g , noise) of the speed V _{v_w} collected by the wheel speed sensor are input.

=a_v,s,a_g)로 추정하게 된다.At this time, if the range of the acceleration (a _{v_w} ) inputted by the conversion is a _{v_w} <0, or the range of the speed (V _{v_w} ) collected from the wheel speed sensor is not within the range of 5 kph <V _{v_w} <10 kph The estimation module 20 removes noise from the collected accelerometer signal Vs and then obtains the acceleration of the acceleration sensor from the wheel speed sensor.

= a _{v, s} , a _g )

On the other hand, if the range of the acceleration (a _{v_w} ) inputted by the conversion is a _{v_w} <0 or if the range of the speed (V _{v_w} ) collected from the wheel speed sensor is within the range of 5 kph <V _{v_w} <10 kph, The delay phenomenon occurring when the acceleration is estimated by the estimation module 20 is compensated by the compensation module 30.

That is, the compensation module 30 receives a time for updating the output of the estimation module 20 while receiving the wheel speed sensor output speed V _{v, w} and the acceleration conversion value a _{v, w} . Will output a flag to determine

=a_{v ,s},a_g)를 를 추정할 수 있게 되는 것이다.The delay phenomenon according to the acceleration estimation of the estimation module 20 is compensated from the flag. Accordingly, in the estimation module 20, the acceleration of the acceleration sensor obtained by removing the noise from the accelerometer signal Vs from the wheel speed sensor (

= a _{v , s} , a _g ) can be estimated.

On the other hand, the acceleration estimated as described above is input to the convergence module unit 13 through the mixing unit 12,

The convergence module unit 13 calculates an inclination angle by performing an operation of subtracting the acceleration conversion value a _{v _w} from the estimated acceleration signals Vs; a _{v , s} , a _g , and noise. By outputting to the skid prevention logic 14 and the idle stop logic 15, it is possible to determine the entry and release time of the climb prevention logic 14 and the idle stop logic 15.

Then, as shown in Table 8 below, of course,

   Global error    10 ~ 4kph section error Before improvement   ± 4.18deg (7%)    ± 2.45deg (4.2%) After improvement   0.99 deg (1.7%)    ± 0.52deg (0.9%)

The inclination angle determination algorithm of the present invention is able to create an effect that the error rate is significantly reduced compared to the conventional inclination angle determination algorithm, and also the splashing phenomenon disappears when the vehicle is stopped.

As described above, the present invention constitutes an inclination angle determination system which eliminates noise of the acceleration sensor and estimates the acceleration sensor's acceleration as the acceleration obtained from the wheel speed sensor, and compensates the delay phenomenon according to the acceleration estimation. By preventing the slope error on the flat surface it is possible to obtain the effect of preventing the risk of vehicle rolling on the slope and delayed start.

The present invention is not limited to the above-described specific preferred embodiments, and various modifications can be made by any person having ordinary skill in the art without departing from the gist of the present invention claimed in the claims. Of course, such changes will fall within the scope of the claims.

Claims (4)

delete Collecting speed from the wheel speed sensor; Converting the collected speed into acceleration; Collecting an accelerometer signal after determining the converted range of acceleration and a range of speed collected from a wheel speed sensor; If the determination result does not belong to the range of acceleration and the speed collected from the wheel speed sensor, noise is removed from the collected accelerometer signals, and the acceleration of the acceleration sensor is estimated from the wheel speed sensor. Estimating acceleration after compensating for the phenomenon; Performing an operation of subtracting an acceleration conversion value from the estimated acceleration; Calculating an inclination angle from the subtraction; And, Determining entrance and release timings of the back slip prevention logic and the idle stop logic from the calculated inclination angle; Tilt angle determination method using an acceleration sensor characterized in that the progress including. The method of claim 2, wherein the compensation of the delay phenomenon, Method for determining the inclination angle using the acceleration sensor, characterized in that the compensation module receives the wheel speed sensor output speed and acceleration conversion value, and outputs a flag for determining the time point for the compensation module to update the output of the estimation module. . The inclination angle using the acceleration sensor according to claim 2 or 3, wherein, after the compensation time of the delay phenomenon, the acceleration estimation operation is re-executed so as to reduce the estimated delay of the actual inclination during driving in a section in which the inclination changes. Judgment method.

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