Vehicle driving support system

Abstract

To teach a degree of risk of deviation seamlessly to a driver by continuously changing a vibration characteristic imparted to a steering according to the degree of risk of deviation.SOLUTION: A vehicle driving support system is configured to impart vibration to steering when a vehicle may deviate from a target travel area. According to a degree of risk of deviation from the target travel area, at least one of a vibration amplitude, a frequency, a time to continue the vibration, and a time to pause the vibration is continuously changed.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present disclosure relates to a driving assistance system for a vehicle.

Background Art

[0002] Patent Document 1 discloses a deviation warning system that gives a warning to a driver when a deviation from the driving lane of a vehicle is detected. The deviation warning system applies vibration to the steering of the vehicle as a warning to the driver. The deviation warning system makes the vibration intensity variable depending on whether the vehicle is turning or not, and when a deviation from the lane is detected and at the same time a turn of the vehicle is detected, the vibration intensity is made smaller compared to the case where no turn of the vehicle is detected.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] As one of the methods for reducing the possibility that a vehicle operated by a driver deviates from a target driving area, a deviation warning is known. A deviation warning is a warning given by a driving assistance system to a driver when a deviation from the target driving area of the vehicle, or a possibility of deviation, is detected. One of the methods of giving a warning is to apply vibration to the steering.

[0005] An object of the present disclosure is to provide a technique capable of seamlessly teaching a driver the degree of deviation warning in a driving assistance system that applies vibration to the steering when there is a possibility that the vehicle deviates from the target driving area.

Means for Solving the Problems

[0006] The present disclosure relates to a driving assistance system for a vehicle. The driving support system is configured to apply vibration to the steering when there is a risk that the vehicle may deviate from the target driving area, and continuously change at least one of the amplitude, frequency, duration of continuous vibration, and duration of vibration pause of the vibration according to the degree of risk of deviation from the target driving area. characterized by this.

Advantages of the Invention

[0007] According to the present disclosure, the vibration characteristics of the vibration applied to the steering are continuously changed according to the degree of risk of deviation. Specifically, at least one of the amplitude, frequency, duration of continuous vibration, and duration of vibration pause is continuously changed. Thereby, the degree of possibility of deviation can be seamlessly taught to the driver.

Brief Description of the Drawings

[0008]

Figure 1

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Embodiments for Carrying Out the Invention

[0009] Embodiments of the present disclosure will be described with reference to the accompanying drawings.​ 1. Summary The driving assistance system for a vehicle according to this embodiment includes a deviation warning function. The deviation warning function is a function that notifies the driver of the risk of deviation by giving visual, auditory, and tactile stimuli to the driver when the vehicle may deviate from the target driving area. The driving assistance system according to this embodiment notifies the risk of deviation by vibrating the steering wheel and giving a tactile stimulus to the driver.

[0010] As an example of the area where the vehicle travels, a road with lanes can be mentioned. When the vehicle travels on a road with lanes, the inside of the lane on which the vehicle travels becomes the target driving area. Another example of the area where the vehicle travels includes a road without lanes or a flat ground. When there is a prohibited driving area where the vehicle's travel is prohibited within the area, the area excluding the prohibited driving area becomes the target driving area.

[0011] The driving assistance system according to this embodiment is further characterized in that the vibration characteristics of the vibration applied to the steering wheel are continuously changed according to the degree of the risk of deviation. The degree of the risk of deviation is calculated by any one or a combination of two or more of the following three methods. The vibration characteristics refer to the characteristics of vibration such as the amplitude, frequency, time for which the vibration continues, and time for which the vibration pauses.

[0012] The first method for calculating the degree of risk of deviation is a method that utilizes the position of the vehicle. When there are lanes in the area where the vehicle is traveling, the greater the lateral distance from the vehicle's traveling position to the center of the lane, that is, the greater the amount of deviation from the center of the lane, the greater the risk of deviation is determined to be. When there is a no-go area in the area where the vehicle is traveling, the smaller the distance from the vehicle's traveling position to the no-go area and the greater the approaching amount to the no-go area, the greater the risk of deviation is determined to be. The degree of risk of deviation may be calculated using either the amount of deviation from the center of the lane or the approaching amount to the no-go area, or may be calculated by combining both. The first calculation method is realized, for example, by a combination of an in-vehicle camera and white line recognition technology, or a combination of GPS and map data indicating the target traveling area.

[0013] The second method for calculating the degree of risk of deviation is a method that utilizes the speed of the vehicle. When there are lanes in the area where the vehicle is traveling, the time until the vehicle deviates from the lane can be obtained from the lateral speed of the vehicle and the lateral distance from the vehicle to the boundary of the lane. Similarly, when there is a no-go area in the area where the vehicle is traveling, the time until the vehicle deviates from the target traveling area can be obtained from the speed of the vehicle and the distance between the vehicle and the no-go area. When assuming that the current vehicle state is maintained, the time it takes for the vehicle to deviate from the target traveling area may be called TTC (Time to Collision). The smaller the TTC, the greater the risk of deviation is determined to be.

[0014] The third method for calculating the degree of risk of deviation is a method of judging from the duration of the state where there is a possibility of deviation. When there are lanes in the area where the vehicle is traveling, the greater the duration of the state where the amount of deviation from the center of the lane exceeds a predetermined threshold, the greater the risk of deviation is determined to be. When there is a no-go area in the area where the vehicle is traveling, the greater the duration of the state where the approaching amount to the no-go area exceeds a predetermined threshold, the greater the risk of deviation is determined to be.

[0015] Figure 1 shows an example of the waveform of the vibration applied to the steering. As shown in Figure 1, the vibration may be repeatedly applied over several cycles with pauses in between. The time for pausing the vibration includes a pause time and a standby time. The pause time is the short pause time between one cycle of the vibration and the next cycle. The standby time is the longer pause time from when a series of cycles of the vibration ends until the next series of cycles begins.

[0016] The greater the degree of risk of deviation, the sooner the driver needs to notice the deviation and correct the position of the vehicle. Therefore, the change in the vibration characteristics is set so that the alarm becomes stronger as the degree of risk of deviation increases.

[0017] That is, when the degree of risk of deviation increases, at least one or more of the following changes are applied to the vibration applied to the steering: an increase in amplitude, an increase in frequency, an increase in the time for which the vibration continues, a shortening of the pause time, and a shortening of the standby time. When the degree of risk of deviation decreases, at least one or more of the following changes are applied to the vibration applied to the steering: a reduction in amplitude, a reduction in frequency, a reduction in the time for which the vibration continues, an increase in the pause time, and an increase in the standby time. By changing the vibration characteristics in this way, it is possible to make the alarm given to the driver stronger as the degree of risk of deviation increases and weaker as it decreases.

[0018] Figure 2 shows an example of a deviation alarm in the comparative technology. The double line indicates the lane in which the vehicle is traveling, and the dashed line indicates the position of the vehicle if it continues its current driving state. In the example of Figure 2, in a scenario where the vehicle is traveling in a lane, it is determined whether there is a risk of deviation from the TTC, and if there is a risk of deviation, an alarm is given to the driver.

[0019] In the example of FIG. 2, when the TTC becomes 1.3 seconds, the first deviation warning is started at (point A), and when the TTC becomes 0.8 seconds, the second deviation warning is started at (point B). Since the degree of the risk of deviation at point B is greater than that at point A, the warning to the driver is set stronger. If the driver does not notice the warning and continues the current driving state, the vehicle will deviate from the lane at the time when the TTC becomes 0 seconds (point C).

[0020] In the comparative technology, a certain threshold value is provided for the parameter representing the degree of the risk of deviation, and when the threshold value is exceeded, a warning is given to the driver. The warning to the driver is in stages and does not change continuously. For example, in the example of FIG. 2, the first type of warning is started at point A, and the intensity of the warning does not change until point B. At point B, the second type of warning is started, and the intensity of the warning does not change until the TTC becomes below the threshold value. Therefore, the driver cannot know how much the degree of the risk of deviation changes before point A or between point A and point B. On the other hand, the driving support system according to the present embodiment can teach the driver the degree of the deviation warning seamlessly by continuously changing the vibration characteristics applied to the steering according to the degree of the risk of deviation.

[0021] 2. Example of Function Arrangement FIG. 3 is a diagram showing an example of the functional arrangement of a driving support system for a vehicle according to the present embodiment. The driving support system includes a deviation warning system 20 and an electric power steering system 30. The electric power steering system 30 includes a basic assist unit 31 and a vibration signal generation unit 32. The basic assist unit 31 generates a signal A that gives an auxiliary torque according to the torque applied to the steering by the driver. When there is a risk of deviation, the deviation warning system 20 gives a request for applying vibration to the steering to the vibration signal generation unit 32 through the communication path 10. The communication path 10 is configured by, for example, CAN (Controller Area Network). The vibration signal generation unit 32 generates a signal B for applying vibration to the steering according to the request. The electric power steering system 30 applies torque and vibration to the steering by sending a signal C generated from the signal A and the signal B to the motor 40.

[0022] FIG. 3 shows the functional arrangement in a conventional driving system where the driver drives at the driver's seat of the vehicle. However, the driving support system according to the present embodiment is not limited to the conventional driving system and may be applied to a remote driving system.

[0023] 3. Example of change in vibration characteristics Hereinafter, an example of the change in vibration characteristics when the driving support system according to the present embodiment applies vibration to the steering will be described.

[0024] 3-1. First example of change in vibration characteristics FIG. 4 is a graph for explaining the first example of the change in vibration characteristics. The horizontal axis represents TTC, and the vertical axis represents the amplitude of the vibration applied to the steering.

[0025] In the first example, the degree of risk of deviation is judged from the TTC, and among the vibration characteristics, the amplitude is changed. That is, the amplitude is continuously increased as the TTC decreases. The region where the amplitude is continuously increased also includes the region where the TTC takes a negative value. This means that the vibration continues even after the vehicle deviates from the target driving region. In the first example, the amplitude is linearly increased as the TTC decreases, but the shape of the increase is not limited to linear. For example, the shape of the increase may be exponential or quadratic.

[0026] In the first example, although the amplitude is increased, the parameter to be changed is not limited to the amplitude, and it may be any of the frequency, the time for which the vibration continues, the time for which the vibration pauses, or a plurality of parameters may be changed simultaneously. As a parameter representing the degree of risk of deviation, a parameter other than the TTC may be used. Also, it is assumed that the shape of the graph is changed according to the scene. Specific examples of the scene for changing the shape of the graph will be described after 3-2.

[0027] 3-2. Second Example of Change in Vibration Characteristics FIG. 5 is a graph for explaining a second example of the change in vibration characteristics. The horizontal axis represents the TTC, and the vertical axis represents the amplitude of the vibration applied to the steering. The solid line represents the graph in the case of the remote driving system, and the broken line represents the graph in the case of the conventional driving system.

[0028] In the second example, as in the first example, the amplitude is increased as the TTC decreases. However, the shape of the increase is different between the remote driving system and the conventional driving system. Since the sense of distance, speed, and acceleration is weak in the remote driving system, there is a possibility that the frequency of lane departure increases when operating with the same operating feeling as the conventional driving system. Therefore, the shape of the graph is set so that the amplitude becomes larger for the same TTC value. However, in any scene, the amplitude increases as the TTC decreases, that is, the shape of the graph is determined so that the vibration characteristics change continuously according to the degree of risk of deviation.

[0029] 3-3. Third Example of Change in Vibration Characteristics FIG. 6 is a graph for explaining a third example of changes in vibration characteristics. The horizontal axis represents TTC, and the vertical axis represents the amplitude of the vibration applied to the steering. The solid line represents the graph when the load is a precision instrument or when there is a standing passenger, and the dashed line represents the graph in other cases.

[0030] In the third example, similar to the first and second examples, the amplitude increases as TTC decreases. However, the shape of the increase is different between the case where the load is a precision instrument or there is a standing passenger and other cases. When the load is a precision instrument or there is a standing passenger, the risk of damage due to deviation from the target driving area increases, so the demand to drive without deviating from the target driving area becomes higher. Therefore, the shape of the graph is set so that the amplitude becomes larger for the same TTC value and the application of vibration starts from a larger TTC value. However, in any scenario, the amplitude increases as TTC decreases, that is, the shape of the graph is determined so that the vibration characteristics change continuously according to the degree of risk of deviation.

[0031] In the second and third examples, TTC is used as a parameter representing the degree of risk of deviation, and the amplitude among the vibration characteristics is linearly increased. However, as a parameter representing the degree of risk of deviation, parameters other than TTC may be used. The parameter to be changed is not limited to the amplitude, and it may be any of the frequency, the time for which the vibration continues, the time for which the vibration pauses, or a plurality of parameters may be changed simultaneously. Also, the shape of the change in the graph may be a shape other than linear.

[0032] 3-4. Other Examples of Changes in Vibration Characteristics As shown in the second example and the third example, it is assumed that the graph of the change in vibration characteristics has different shapes depending on the scene. As other examples, it is assumed that the graph has different shapes depending on the vehicle class, the driver's skill level, the driver's preference, and the driver's physical condition. For example, since the damage when deviating from the lane may increase as the vehicle class is larger, it is assumed that the amount of change in vibration characteristics is increased as the vehicle class is larger. Also, for example, since the possibility of deviating from the lane increases as the driver's skill level is lower, it is assumed that the amount of change in vibration characteristics is increased as the driver's skill level is lower.

[0033] 4. Effects As described above, the driving support system according to the present embodiment continuously changes the vibration characteristics applied to the steering according to the degree of the risk of deviation. Thereby, it is possible to seamlessly teach the driver the degree of the deviation warning.

Description of Reference Numerals

[0034] 10 Communication path 20 Deviation warning system 30 Electric power steering system 31 Basic assist unit 32 Vibration signal generation unit 40 Motor

Claims

Claim 1 A driving assistance system for a vehicle, configured to apply vibration to a steering wheel gripped by a driver of the vehicle when there is a risk that the vehicle may deviate from a target driving area, continuously changing at least one of vibration characteristics including amplitude, frequency, time for which vibration continues, and time for which vibration pauses according to the degree of the risk of deviation from the target driving area, when the vehicle is a remotely operated vehicle, making a change amount when continuously changing the vibration characteristics according to the degree of the risk of deviation larger than when the vehicle is not a remotely operated vehicle A driving assistance system.

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