KR102303230B1 - Apparatus and method for estimating radius of curvature in vehicle - Google Patents

Abstract

The present invention relates to an apparatus and method for estimating a radius of curvature of a vehicle that accurately estimate a radius of curvature with respect to a traveling direction of a vehicle using a steering angle signal and a yaw rate signal regardless of vehicle speed and road environment, wherein the radius of curvature The estimator includes: a radius of curvature calculator configured to calculate each radius of curvature value using a yaw rate signal and a steering angle signal of the vehicle while driving; a filtering unit configured to filter a signal for each radius of curvature calculated by the radius of curvature calculating unit in a predetermined band; and a radius of curvature estimator for estimating a final radius of curvature value by using each radius of curvature value filtered by the filtering unit.

Description

Apparatus and method for estimating radius of curvature in vehicle}

The present invention relates to an apparatus and method for estimating a radius of curvature of a vehicle, and more particularly, to an apparatus and method for estimating a radius of curvature of a vehicle for estimating a driving direction required for selecting a target vehicle of a smart cruise control system.

A smart cruise control (SCC) system is being installed in a vehicle as a driver assist system to improve the driver's convenience.

The smart cruise control system is a convenience device that detects the vehicle in front and measures the distance and relative speed to maintain a constant distance from the vehicle in front without operating the accelerator or brake pedal. In this case, it is necessary to estimate the radius of curvature of the target vehicle according to driving on a curved road or steering operation of a driver.

That is, when the control vehicle travels, accurately selecting a target vehicle having the closest relative distance while existing in the traveling direction of the own vehicle has a great influence on the control performance of the vehicle. To this end, it is necessary to accurately select a target vehicle existing in the driving direction by estimating the driving direction curvature radius of the vehicle to predict the driving direction.

As a method of estimating the radius of curvature in the driving direction of the vehicle for selecting the target target vehicle, there is a method using a steering angle signal, a lateral acceleration signal, and a yaw rate signal. There is a characteristic that appears to be accurate in each of them differently.

For example, when the radius of curvature is estimated using the steering angle signal, the accuracy at low speed is high, but accuracy at high speed is deteriorated.

On the other hand, when the radius of curvature is estimated using the yaw rate signal, the accuracy at high speed is high, but the accuracy at low speed is deteriorated.

In other words, each method of estimating the radius of curvature using the yaw rate signal and the steering angle signal has a difference in effect depending on the vehicle speed as shown in the table below.

steering angle signal

yaw rate signal
Accuracy at low speed
Good
commonly

Accuracy at high speed
weak
Good

That is, the method for estimating the radius of curvature of a vehicle according to the prior art has a problem in that the accuracy of estimating the radius of curvature according to speed or surrounding conditions is deteriorated. And, due to the above characteristics, it is difficult to predict the radius of curvature in the driving direction of the vehicle accurately in both high-speed and low-speed sections. This will cause performance degradation.

Accordingly, it is necessary to secure product competitiveness by estimating and correcting the radius of curvature in the traveling direction of the vehicle effectively regardless of the speed of the vehicle or the road environment by supplementing the problems of the existing method of estimating the radius of curvature of the vehicle.

The present invention is to solve the problems according to the prior art, and an object of the present invention is to accurately determine the radius of curvature for the traveling direction of the vehicle by using the steering angle signal and the yaw rate signal regardless of the speed of the vehicle and the road environment. An object of the present invention is to provide an apparatus and method for estimating the power radius of a vehicle to be estimated.

According to an aspect of the present invention, there is provided an apparatus for estimating a radius of curvature of a vehicle, comprising: a radius of curvature calculator for calculating each radius of curvature value using a yaw rate signal and a steering angle signal of the vehicle while driving; a filtering unit configured to filter a signal for each radius of curvature calculated by the radius of curvature calculating unit in a predetermined band; and a radius of curvature estimator for estimating a final radius of curvature value by using each radius of curvature value filtered by the filtering unit.

The radius of curvature calculator may include: a yaw rate radius calculator configured to calculate a yaw rate radius of curvature of the vehicle using a yaw rate signal detected through a yaw rate sensor of the vehicle; and a steering angle curvature radius calculator configured to calculate a steering angle curvature radius of the vehicle by using a steering angle signal sensed through a steering angle sensor of the vehicle.

The filtering unit may include: a first filtering unit configured to filter the signal for the yaw rate radius of curvature value calculated by the radius of curvature calculation unit for a predetermined band; and a second filtering unit configured to filter the signal for the steering angle radius of curvature value calculated by the radius of curvature calculator for a predetermined band.

The first filtering unit may be configured as a high pass filter (HPF), and the second filtering unit may be configured as a low pass filter (LPF).

The radius of curvature estimating unit estimates the sum of the radius of curvature of the yaw rate filtered by the high-pass filter and the radius of curvature of the steering angle filtered by the low-pass filter.

Meanwhile, a method for estimating a radius of curvature of a vehicle according to another aspect of the present invention includes: calculating each radius of curvature value using a yaw rate signal and a steering angle signal of the vehicle while driving; filtering a signal for each calculated radius of curvature value by a predetermined band; and estimating a final radius of curvature value using each of the filtered radius of curvature values.

Calculating the radius of curvature may include: calculating the radius of curvature of the vehicle using a yaw rate signal detected through a yaw rate sensor of the vehicle; and calculating a steering angle curvature radius of the vehicle by using a steering angle signal sensed through a steering angle sensor of the vehicle.

The filtering may include: filtering the signal for the calculated yaw rate radius of curvature value for a predetermined band; and filtering the signal for the calculated steering angle radius of curvature value for a predetermined band.

The signal for the calculated yaw rate radius of curvature value is filtered using a high pass filter (HPF), and the signal for the steering angle radius of curvature value is filtered using a low pass filter (LPF). .

In the estimating of the radius of curvature value, the final radius of curvature value is estimated by adding the yaw rate radius of curvature value filtered by the high pass filter and the radius of curvature of the steering angle filtered by the low pass filter.

According to the present invention, in the case of the conventional radius of curvature estimation method, the accuracy of the radius of curvature decreases in various environments such as vehicle speed, inclination / inclination, etc. for each method is solved, and the target target selection accuracy of SCC and AEB vehicles is increased. there is

In addition, accurate and safe driving can be provided to the driver by effectively detecting the vehicle ahead by effectively predicting the radius of curvature in the driving direction even in various environments.

In addition, since it is not necessary to install additional sensors such as a camera and GPS to accurately estimate the radius of curvature, there is an effect of reducing the cost and the risk of electromagnetic waves to the vehicle driver.

1 is a diagram illustrating a block configuration of an apparatus for estimating a radius of curvature of a vehicle according to the present invention;
2 is a view showing an operation flowchart for a method for estimating a radius of curvature of a vehicle according to the present invention;

Advantages and features of the present invention, and a method for achieving them will become apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various different forms, and only these embodiments allow the disclosure of the present invention to be complete, and common knowledge in the art to which the present invention pertains. It is provided to fully inform the possessor of the scope of the invention, and the present invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout.

In describing the embodiments of the present invention, if it is determined that a detailed description of a well-known function or configuration may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted. In addition, the terms to be described later are terms defined in consideration of functions in an embodiment of the present invention, which may vary according to intentions or customs of users and operators. Therefore, the definition should be made based on the content throughout this specification.

Hereinafter, an apparatus and method for estimating a radius of curvature of a vehicle according to the present invention will be described in detail with reference to the accompanying drawings.

1 is a diagram illustrating a block configuration of an apparatus for estimating a radius of curvature of a vehicle according to the present invention.

1 , the apparatus for estimating the radius of curvature of a vehicle according to the present invention includes a yaw rate sensor 100 , a steering angle sensor 110 , a first radius of curvature calculator 120 , and a second radius of curvature calculator 130 , a first filtering unit 140 , a second filtering unit 150 , and a radius of curvature estimator 160 may be included.

The yaw rate sensor 100 is mounted on a vehicle to detect a yaw rate signal value of the vehicle and provide it to the first radius of curvature calculator 120 . Here, the yaw rate value is a change speed value of the trajectory angle of the vehicle measured in degrees per second about a rotation about a vertical axis passing through the center of gravity of the vehicle.

The steering angle sensor 110 is installed in the vehicle to detect a steering angle signal of the vehicle and provide it to the second radius of curvature calculator 130 . Here, the steering angle signal represents a steering wheel angle value of the driver, that is, a steering angle value of a steering wheel of the vehicle.

The first radius of curvature calculator 120 calculates the radius of curvature of the vehicle by using the yaw rate signal provided from the yaw rate sensor 100 . Here, the yaw rate radius of curvature is calculated using the yaw rate data provided from the yaw rate sensor 100 to calculate the radius of curvature for the driving direction of the vehicle. Here, the method for calculating the yaw rate radius of curvature in the first radius of curvature calculating unit 120 using the yaw rate value detected by the yaw rate sensor 100 is a known technique, and a detailed description thereof will be omitted.

The second radius of curvature calculator 130 calculates a radius of curvature with respect to the driving direction of the vehicle by using the steering angle data provided from the steering angle sensor 110 . Here, the method of calculating the radius of curvature with respect to the traveling direction of the vehicle by using the steering angle data of the second radius of curvature calculating unit 130 is a well-known technique, and a detailed description thereof will be omitted.

The first filtering unit 140 performs high-pass filtering on the signal for the yaw rate radius of curvature calculated by the first radius of curvature calculator 120 , and provides the filtered signal to the radius of curvature estimator 160 . Here, the first filtering unit 140 may be configured as a high pass filter (HPF), and when calculating the radius of curvature using the yaw rate signal, the HPF is used because it has stable characteristics at high speed.

The second filter 150 performs low-pass filtering on the signal for the steering angle radius of curvature calculated by the second radius of curvature calculator 130 , and then provides the filtered signal to the radius of curvature estimator 160 . Here, the second filtering unit 150 may be configured as a low pass filter (LPF), and when the radius of curvature is calculated using the steering angle signal, the LPF may be used because it has a stable characteristic at a low speed.

Meanwhile, the first and second filtering units 140 and 150 , that is, the HPF and the LPF may be expressed as discrete times to be easily applied to the estimation of the radius of curvature. Here, the specific expression of discrete time will be described later.

The radius of curvature estimator 160 estimates the final radius of curvature by adding the signals respectively output from the first filtering unit 140 and the second filtering unit 150 . In this case, it is possible to obtain the radius of curvature data having good characteristics at both high and low speeds.

A detailed operation of the apparatus for estimating the radius of curvature of the vehicle according to the present invention configured as described above will be described.

First, the first and second radius of curvature calculators 120 and 130 calculate each radius of curvature by using the yaw rate signal and the steering angle signal detected by the yaw rate sensor 100 and the steering angle sensor 110 . Here, a method of calculating the yaw rate radius of curvature and the steering angle radius of curvature will be omitted as well-known techniques.

As such, the signal for the yaw rate radius of curvature calculated by the first radius of curvature calculator 120 is provided to the first filtering unit 140 , that is, the HPF, and is filtered.

More specifically, as shown in FIG. 1 , the output voltage, charge amount, and current value of the HPF 140 may be calculated by Equations 1, 2, and 3 below, respectively.

Here, V _in is the input voltage, V _out is the output voltage, C is the capacitor value, R is the resistance value, i is the current, and Q is the amount of charge.

Substituting Equation 2 and Equation 2 into Equation 1 in the above Equation, Equation 4 below is arranged.

Equation 4 above can be expressed as discrete time. That is, assuming that the input and output are sampled at l constant time, V _in can be expressed as (x1, x2, ...,xn) and V _out is expressed as (y1, y2,...,yn) can be If Equation 4 is rearranged using this, it can be rearranged as Equation 5 below.

Here, Δt is the sampling time.

If Equation 5 is rearranged, it can be expressed as discrete time as in Equation 6 below.

이다. Here, the

am.

In addition, the signal for the steering angle radius of curvature calculated by the second radius of curvature calculating unit 130 shown in FIG. 1 is provided to the second filtering unit 150, ie, the LPF, and filtered.

More specifically, as shown in FIG. 1 , the output voltage, charge amount, and current value of the LPF 150 may be calculated by Equations 7, 8, and 9, respectively.

Substituting Equation 8 and Equation 9 into Equation 7, it can be expressed as Equation 10 below.

Equation 10 can be expressed as discrete time. That is, assuming that the input and output are sampled at a constant time, V _in can be expressed as (x1, x2,...xn), and V _out can be expressed as (y1, y2,...,yn). Using this to rearrange Equation 10, it can be expressed as Equation 11 below.

Here, Δt means a sampling time.

If Equation 11 is rearranged, it can be expressed as discrete time as in Equation 12 below.

이다. Here, α is

am.

As described above, the signals filtered through the HPF 140 and the LPF 150 shown in FIG. 1 are respectively provided to the radius of curvature estimator 160 .

The radius of curvature estimator 160 calculates a final radius of curvature by adding the radius of curvature signals filtered by the HPF 140 and the LPF 150 respectively.

A method of calculating the final radius of curvature by the radius of curvature estimator 160 will be described in more detail.

First, the steering angle curvature radius calculated by the second radius of curvature calculator 130 shown in FIG. 1 is Ks(i), and the yaw rate radius of curvature calculated by the first radius of curvature calculator 120 is Ky(i). ), assuming that Ks(i) is a value filtered through the LPF 150 is fKs(i), and Ky(i) is a value filtered through the HPF 140 is fKy(i), the fKs (i) and fKy(i) can be expressed as Equations 13 and 14 below.

Here, β is 1-α.

_{Accordingly, the radius of curvature K est} estimated by the radius of curvature estimator 160 may be expressed as Equation 15 below.

Accordingly, when Equations 13 and 14 are substituted into Equation 15, a final radius of curvature value as shown in Equation 16 below is estimated.

Here, the gyro(i) is a rate data value detected by the gyro sensor, although not shown in FIG. 1 .

A method for estimating a radius of curvature of a vehicle according to the present invention corresponding to the operation of the apparatus for estimating a radius of curvature of a vehicle according to the present invention as described above will be described in stages with reference to FIG. 2 .

2 is a diagram illustrating an operation flowchart for a method for estimating a radius of curvature of a vehicle according to the present invention.

As shown in FIG. 2 , first, a yaw rate signal and a steering angle signal of a vehicle are sensed using a yaw rate sensor and a steering angle sensor ( S101 and S102 ).

Next, a radius of curvature of a yaw rate is calculated using the sensed yaw rate signal (S103), and a radius of curvature of a steering angle is calculated using the sensed steering angle signal (S104). Here, since the method of calculating the yaw rate radius of curvature and the steering angle radius of curvature in steps S103 and S104 is a known technique, a detailed description thereof will be omitted.

Then, the signal for the radius of curvature of the yaw rate calculated in step S103 is filtered through a high pass filter (HPF) (S105), and the signal for the radius of curvature of the steering angle calculated in step S104 is subjected to a low pass filter (LPF). ) to perform filtering (S106). Here, since the filtering method through the HPF and the LPF has been described in detail by the above equations, a description thereof will be omitted.

The final radius of curvature is estimated by adding the yaw rate curvature radius value and the steering angle curvature radius value filtered in steps S105 and S106, respectively (S107). Here, since the method of estimating the final radius of curvature value in step S107 has been described in detail above, a detailed description thereof will be omitted.

On the other hand, although the apparatus and method for guiding a moving object using laser light according to the present invention have been described according to the embodiments, the scope of the present invention is not limited to the specific embodiments, and those with ordinary knowledge in relation to the present invention Various alternatives, modifications, and changes can be implemented within the obvious scope.

Accordingly, the embodiments and the accompanying drawings described in the present invention are for explanation rather than limiting the technical spirit of the present invention, and the scope of the technical spirit of the present invention is not limited by these embodiments and the accompanying drawings. . The protection scope of the present invention should be construed by the claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present invention.

100: yaw rate sensor
110: steering angle sensor
120: first radius of curvature calculator
130: second radius of curvature calculator
140: first filtering unit
150: second filtering unit
160: radius of curvature estimation unit

Claims (4)

In the device for estimating the radius of curvature of a vehicle,
a radius of curvature calculator that calculates each radius of curvature value using a yaw rate signal and a steering angle signal of the vehicle while driving;
A first filtering unit that filters the signal for the yaw rate radius of curvature value calculated by the radius of curvature calculating unit using a high pass filter (HPF) for a predetermined band and the radius of curvature calculating unit calculates Each of the radius of curvature values calculated by the radius of curvature calculator includes a second filtering unit that filters the signal for the steering angle radius of curvature value for a predetermined band using a low pass filter (LPF). a filtering unit that filters the signal for a predetermined band; and
and a radius of curvature estimator for estimating a final radius of curvature value by summing the yaw rate radius of curvature filtered by the high pass filter and the radius of curvature of the steering angle filtered by the low pass filter. According to claim 1,
The radius of curvature calculation unit,
a yaw rate curvature radius calculator for calculating a yaw rate curvature radius of the vehicle using a yaw rate signal detected through a yaw rate sensor of the vehicle; and
and a steering angle radius of curvature calculator for calculating a steering angle radius of curvature of the vehicle by using a steering angle signal detected through a steering angle sensor of the vehicle. In the method of estimating the radius of curvature of the vehicle,
calculating each radius of curvature value using a yaw rate signal and a steering angle signal of the vehicle while driving;
The signal for the calculated yaw rate radius of curvature value is filtered using a high-pass filter (HPF) for a predetermined band, and the signal for the calculated steering angle radius of curvature value is converted to a low-pass filter (LPF) for a predetermined band. ) to perform filtering using a predetermined band-filtering signal for each calculated radius of curvature value; and
estimating a final radius of curvature value by summing the yaw rate radius of curvature value filtered by the high pass filter and the radius of curvature of the steering angle filtered by the low pass filter; 4. The method of claim 3,
Calculating the radius of curvature comprises:
calculating a yaw rate curvature radius of the vehicle using a yaw rate signal detected through a yaw rate sensor of the vehicle; and
The method of estimating a radius of curvature of a vehicle, comprising the step of calculating a radius of curvature of a steering angle of the vehicle by using a steering angle signal detected through a steering angle sensor of the vehicle.

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