Avoidance motion discrimination system

Abstract

To provide an avoidance motion discrimination system capable of highly precisely discriminating an avoidance motion of a vehicle against an obstacle.SOLUTION: An avoidance motion discrimination system includes a calculation unit that calculates a quantity of wobble on the basis of a variation quantity of a yaw rate of a vehicle associated with wobble of the vehicle caused by a driver's driving maneuver, and a discrimination unit that discriminates an avoidance motion of the vehicle against an obstacle on the basis of the yaw rate and the quantity of wobble.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to an avoidance operation determination device.

Background Art

[0002] For example, Patent Document 1 describes that an avoidance operation of a vehicle with respect to an obstacle on the traveling path is detected by comparing a sensor value of a steering operation with a predetermined threshold value.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, since the steering operation depends on the driver's personal skill and habit, it is difficult to accurately determine the avoidance operation by the above method. For example, in the case of a novice driver, when driving through a curve, the steering angle of the steering wheel is unstable and fluctuates slightly, causing the vehicle to wobble, and this behavior may be erroneously detected as an avoidance operation.

[0005] Therefore, the present invention has been made in view of the above problems, and an object thereof is to provide an avoidance operation determination device that can accurately determine an avoidance operation of a vehicle with respect to an obstacle.

Means for Solving the Problems

[0006] The avoidance operation determination device of the present invention includes a calculation unit that calculates the amount of wobbling based on a change amount of a yaw rate of the vehicle accompanying the wobbling of the vehicle due to a driving operation of a driver, and a determination unit that determines an avoidance operation of the vehicle with respect to an obstacle based on the yaw rate and the amount of wobbling.

Effects of the Invention

[0007] According to the present invention, it is possible to accurately determine the avoidance operation of a vehicle with respect to an obstacle.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Embodiments for Carrying Out the Invention

[0009] (Configuration of Vehicle System) FIG. 1 is a diagram showing the configuration of a vehicle system 9 and an example of the traveling locus T of a vehicle V. In this example, an example is given in which a vehicle V such as a hybrid vehicle travels on a curved road RD. On the road RD, there is an obstacle X such as a falling object from another vehicle. The vehicle V travels so as to avoid the obstacle X.

[0010] For example, in the case of a novice driver, when traveling on a curve, the steering angle of the steering wheel is not stable and the vehicle V sways slightly due to minute fluctuations. For this reason, for example, the traveling locus T of the vehicle V sways left and right with respect to the traveling direction and is drawn so as to bypass the obstacle X. Among the traveling locus T, the fluctuation of the vehicle V is represented in the area Ka in front of the obstacle X, and the avoidance operation of the vehicle V is represented in the area Kb near the obstacle X. The vehicle system 9 mounted on the vehicle V has the following configuration in order to distinguish between the fluctuation and the avoidance operation.

[0011] Vehicle system 9 includes an ECU (Electronic Control Unit) 1, a yawing sensor 2, a GPS (Global Positioning System) 3, a map database device (map DB) 4, and a data communication module (DCM: Data Communication Module) 5. The yawing sensor 2 detects the yaw rate, which is the acceleration in the yawing direction of the vehicle V. The GPS 3 detects the latitude and longitude as the position of the vehicle V. The map DB 4 is, for example, a car navigation system and includes map information such as roads RD.

[0012] The ECU 1 is an example of an avoidance operation determination device. The ECU 1 is a computer including a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like. The ECU 1 operates the CPU according to a program stored in the ROM. The ECU 1 not only controls, for example, the engine and the motor of the power source, but also determines the avoidance operation of the vehicle V.

[0013] As software functions, the ECU 1 has an acquisition unit (Aq) 10, a calculation unit (Pf) 11, a determination unit (Dt) 12, and a generation unit (Pr) 13. The acquisition unit 10 acquires the yaw rate from the yawing sensor 2 at regular time intervals. The acquisition unit 10 stores the yaw rate in a storage means such as a memory at any time. The calculation unit 11 calculates the amount of wobbling (wobbling amount) based on the change amount of the yaw rate accompanying the wobbling of the vehicle V due to the driver's driving operation. The determination unit 12 determines the avoidance operation of the vehicle V with respect to the obstacle X based on the yaw rate and the wobbling amount. The specific determination method will be described later.

[0014] When the determination unit 12 determines an avoidance operation, the generation unit 13 generates position information of the obstacle X based on the detected value of the GPS 3 and the map DB 4 according to the timing of the avoidance operation. The position information is used, for example, as road traffic information and indicates the position of a specific road such as "near the exit of Tunnel △ on National Route 〇". The generation unit 13 outputs the position information of the obstacle X to the DCM 5.

[0015] DCM5 is connected to the Internet NW by wireless communication means. DCM5 transmits the position information of the obstacle X to the traffic information server 8 via the Internet NW. The traffic information server 8 collects the position information of the obstacle X and provides it as road traffic information.

[0016] (Calculation method of wobbling amount) FIG. 2 is a diagram showing an example of a method for calculating the wobbling amount from the yaw rate of the vehicle V. In graphs Ga to Gc, the horizontal axis represents time (ms), and the vertical axis represents the yaw rate (m / s 2 ). Each of the graphs Ga to Gc corresponds to the vehicle V during the curve running shown in FIG. 1. However, for the sake of convenience of explanation, the avoidance operation of the obstacle X is shown only by the dotted line P in the graph Gc.

[0017] Graph Ga shows the time change of the yaw rate (solid line) detected by the yaw sensor 2 and the time change of its smoothed value M (dashed line). The acquisition unit 10 collects the yaw rate from the yaw sensor 2 at regular intervals T1 and T2. The calculation unit 11 smooths the yaw rate at intervals T1 and T2 by smoothing means such as a low-pass filter. As a result, the yawing component corresponding to the wobbling of the vehicle V is removed from the yaw rate, and the yawing component along the turning direction of the road RD is extracted. In the following description, the smoothed value M is referred to as the "road yaw rate".

[0018] Graph Gb shows the yaw rate corresponding to the vehicle V's sway (hereinafter referred to as the lateral movement yaw rate) and its standard deviation D. The calculation unit 11 calculates the lateral movement yaw rate by subtracting the road yaw rate from the yaw rate detected by the yaw sensor 2 for each of the periods T1 and T2. This lateral movement yaw rate represents the amount of change in the yaw rate accompanying the sway of the vehicle V. The calculation unit 11 calculates the standard deviation D of the lateral movement yaw rate as the amount of sway of the vehicle V for each of the periods T1 and T2. Since the standard deviation D indicates the degree of variation of the lateral movement yaw rate, it can accurately represent the amount of sway according to the habits and skills of the driver of the vehicle V. Note that the calculation unit 11 may calculate the average value of the absolute values of the lateral movement yaw rate instead of the standard deviation D as the amount of sway.

[0019] Graph Gc shows an example of discrimination of avoidance operations for each of the amplitudes A1 and A2 of the yaw rate detected by the yaw sensor 2. The dotted line P in graph Gc indicates an avoidance operation with respect to the obstacle X. The discrimination unit 12 detects one or more amplitudes A1 and A2 from the maximum value and the minimum value (see the circles on the dotted line) adjacent to each other in the yaw rate detected by the yaw sensor 2. The discrimination unit 12 discriminates the avoidance operation based on the amount of sway calculated from the yaw rate in the period T1 and the amplitudes A1 and A2 of the yaw rate within the next period T2.

[0020] For example, the discrimination unit 12 compares the value obtained by subtracting the standard deviation D from the magnitudes of the amplitudes A1 and A2 with a predetermined threshold value. Thereby, the discrimination unit 12 discriminates the amplitude A2 that may be an avoidance operation of the vehicle V from the amplitude A1 that may be a sway of the vehicle V. Since the amplitude A1 is a variation due to the sway of the vehicle, it is smaller than the amplitude A2 (see the dotted line P) due to the avoidance operation. Therefore, the two can be discriminated by this comparison. Note that the threshold value is set to an appropriate value based on, for example, the results of prior simulations or experiments.

[0021] The determination unit 12 determines whether an avoidance operation is performed for the amplitude A2 that may be an avoidance operation of the vehicle V. As an example, for the determination of the avoidance operation, at least one of the time width of the amplitude A2 (the interval on the time axis between the maximum value and the minimum value) and the maximum slope of the yaw rate in the amplitude A2 (the maximum absolute value of the time derivative) can be used. The determination unit 12 determines that the amplitude A2 is an avoidance operation when at least one of the time width of the amplitude A2 and the maximum slope of the yaw rate in the amplitude A2 is equal to or greater than a predetermined value.

[0022] In this way, since the ECU 1 calculates the amount of vehicle V's wobbling from the yaw rate and discriminates the avoidance operation, for example, compared with a discrimination method such as comparing the operation amount of the steering wheel with a threshold value, highly accurate discrimination is possible.

[0023] (Avoidance operation discrimination process) FIG. 3 is a flowchart showing an example of the avoidance operation discrimination process. This process is executed, for example, at a fixed time period, but is not limited to this.

[0024] First, the calculation unit 11 acquires yaw rate data for the period Ti (i: positive integer) from the acquisition unit 10 (step St1). Next, the calculation unit 11 calculates the road yaw rate by smoothing the yaw rate (step St2). Next, the calculation unit 11 calculates the lateral movement yaw rate by subtracting the road yaw rate from the original yaw rate (step St3). Next, the calculation unit 11 calculates the standard deviation D of the lateral movement yaw rate as the amount of wobbling (step St4).

[0025] Next, the determination unit 12 acquires yaw rate data for the next period Ti + 1 from the acquisition unit 10 (step St5). Next, the determination unit 12 detects one or more amplitudes from the maximum value and the minimum value adjacent to each other on the time axis in the yaw rate data (step St6). Next, the determination unit 12 calculates the magnitude (A) of the amplitude from the difference between the maximum value and the minimum value of one amplitude (step St7). Next, the determination unit 12 compares the difference (A - D) between the magnitude of the amplitude and the amount of wobbling with the threshold value TH (step St8).

[0026] When A-D>TH holds (Yes in step St8), the discrimination unit 12 determines that the amplitude is more likely to be caused by the avoidance operation than the vehicle's wobbling, and performs the above-described avoidance operation determination on the yaw rate data for period Ti+1 (step St9). Also, when A-D≤TH holds (No in step St8), the discrimination unit 12 determines that the amplitude is caused by wobbling and does not perform the avoidance operation determination.

[0027] Next, the discrimination unit 12 determines the presence or absence of other amplitudes during the yaw rate (step St10). If there are other amplitudes (Yes in step St10), each process after step St6 is executed again. If there are no other amplitudes (No in step St10), this process ends. In this way, the avoidance operation discrimination process is performed.

[0028] The above-described embodiment is a preferred example of the present invention. However, it is not limited thereto, and various modifications can be made without departing from the gist of the present invention.

Explanation of Reference Numerals

[0029] 1 ECU (Avoidance Operation Discrimination Device), 11 Calculation Unit, 12 Discrimination Unit, V Vehicle, X Obstacle

Claims

【Claim 1】 A calculation unit that calculates the amount of vehicle sway based on the amount of change in the yaw rate of the vehicle accompanying the sway of the vehicle due to the driving operation of the driver; A determination unit that determines the avoidance operation of the vehicle with respect to an obstacle based on the yaw rate and the amount of sway; An avoidance operation determination device.

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