JP2017210119A - Parking support device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a parking support device which can improve yaw angle calculation accuracy, enhance self-position estimation accuracy, and which has high robust property even on a bad road surface.SOLUTION: A self-position estimation part 2 for calculating a position of an own-vehicle and a posture angle, in which a position of the own vehicle when parking support is started, is a reference position, comprises: a first yaw angle calculation part 12 for calculating a first yaw angle of the own vehicle; a second yaw angle calculation part 13 for calculating a second yaw angle of the own vehicle based on a lateral wheel movement distance of a front or a rear wheel; and a third yaw angle calculation part 14 for calculating a third yaw angle of the own vehicle, based on a steering angle and a vehicle speed. A combined yaw angle calculation part 15 calculates a combined yaw angle by adjusting a combination ratio of the first yaw angle, the second yaw angle, and the third yaw angle, based on the vehicle state, and an own-vehicle position posture angle calculation part 16 calculates the position of the own vehicle and the posture angle, based on the calculated combined yaw angle and the vehicle speed.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a parking assist device that automatically guides a vehicle to a certain target parking position, and more particularly to a yaw angle calculation method used for self-position estimation.

As a yaw angle calculation device, for example, there is a parking assistance device disclosed in Patent Document 1.
In this parking assistance device, the yaw angle is calculated by integrating the output values of the yaw rate sensors mounted on the vehicle. Based on the past yaw rate sensor output value stored in the buffer memory, the average of the past yaw rate sensor output value is calculated, and the average value of the yaw rate sensor output value over the predetermined time from the time when the yaw angle reference position is set is initialized. Then, the yaw angle is calculated by time-integrating the difference between the initial value and the yaw rate sensor output value.
In general, a technique called dead reckoning is known as a technique for estimating the vehicle position and the vehicle attitude angle. In dead reckoning, self-position estimation is performed from the travel distance and yaw angle of the vehicle. In this self-position estimation, the yaw angle is calculated from the yaw rate acquired by the yaw rate sensor, the moving distance of the vehicle is calculated from the vehicle speed acquired by the vehicle speed sensor, and based on the calculated yaw angle and moving distance, Estimate the vehicle attitude angle.

Japanese Patent No. 3599000 (pages 3-7, Fig. 1)

However, in the parking assistance device described in Patent Document 1, since the yaw angle is calculated by integrating the yaw rate sensor output value, noise is present in the yaw rate sensor output in the case of a road surface condition that is susceptible to vibration from the road surface such as a bad road. When superposed, the accuracy and accuracy of sensor output decreases.
Thus, when the yaw angle is calculated using the output value of the yaw rate sensor whose sensor output accuracy has decreased, errors are likely to accumulate, particularly in an environment where the road surface is uneven, such as a rough road. The parking route including the position and posture of the vehicle is different from the actual route.
Eventually, there was a problem that the vehicle was parked at a position different from the target parking position.

  The present invention has been made to solve the above-described problems, and has an object to improve a yaw angle calculation accuracy, a high self-position estimation accuracy, and a robust parking assist device even on a rough road surface. And

In the parking assistance apparatus according to the present invention, the parking assistance apparatus is configured to provide parking assistance, and includes a steering angle detection unit that detects a steering angle of the own vehicle, and the own vehicle when the parking assistance is started. A self-position estimation unit that calculates the position and posture angle of the host vehicle using the steering angle detected by the steering angle detection unit with the position of the vehicle as a reference position, and the self-position estimation unit detects the yaw rate of the host vehicle Based on the yaw rate detection unit, the wheel speed detection unit that detects the left and right wheel speeds and the left and right wheel movement distance of the front or rear wheel of the host vehicle, and the vehicle speed based on the left and right wheel speeds of the front or rear wheels detected by the wheel speed detection unit A first yaw angle calculation that calculates a first yaw angle of the host vehicle based on the yaw rate detected by the yaw rate detection unit, a vehicle situation detection unit that detects a vehicle situation during parking assistance Department and the car A second yaw angle calculation unit that calculates a second yaw angle of the host vehicle based on the left and right wheel movement distance of the front wheel or rear wheel detected by the speed detection unit, and the steering angle and vehicle speed detected by the steering angle detection unit Based on the vehicle speed calculated by the calculation unit, the third yaw angle calculation unit that calculates the third yaw angle of the host vehicle, and the first yaw angle and the second yaw angle based on the vehicle situation detected by the vehicle situation detection unit The position of the vehicle is adjusted based on the combined yaw angle calculated by the combined yaw angle calculated by the combined yaw angle and the third yaw angle and calculating the combined yaw angle and the vehicle speed and the combined yaw angle calculated unit. And a vehicle position / posture angle calculation unit for calculating the posture angle.

  According to the present invention, a parking assistance device configured to perform parking assistance, the steering angle detecting unit for detecting the steering angle of the own vehicle, and the position of the own vehicle when the parking assistance is started is used as a reference. A self-position estimating unit that calculates the position and posture angle of the host vehicle using the steering angle detected by the steering angle detecting unit as a position, and the self-position estimating unit includes a yaw rate detecting unit that detects the yaw rate of the host vehicle; A vehicle speed detection unit that detects the left and right wheel speeds and the left and right wheel movement distances of the front or rear wheels of the host vehicle, and a vehicle speed that calculates a vehicle speed based on the left and right wheel speeds of the front wheels or the rear wheels detected by the wheel speed detection unit. A calculation unit, a vehicle status detection unit that detects a vehicle status during parking assistance, a first yaw angle calculation unit that calculates a first yaw angle of the host vehicle based on the yaw rate detected by the yaw rate detection unit, and wheels Detected by speed detector Calculated by the second yaw angle calculation unit for calculating the second yaw angle of the host vehicle and the steering angle and vehicle speed calculation unit detected by the steering angle detection unit based on the left and right wheel movement distance of the front wheel or the rear wheel. A first yaw angle, a second yaw angle, and a third yaw angle based on the vehicle speed detected by the vehicle condition detected by the third yaw angle calculation unit that calculates the third yaw angle of the host vehicle based on the vehicle speed The position and posture angle of the host vehicle are calculated based on the combined yaw angle calculation unit that calculates the combined yaw angle and the combined yaw angle calculated by the vehicle speed and the combined yaw angle calculation unit. Since the vehicle position / posture angle calculation unit is included, the yaw angle calculation accuracy can be improved, the self-position estimation accuracy can be improved, and the parking assist device can be highly robust even on bad road surfaces.

It is a block diagram which shows schematic structure of the parking assistance apparatus by Embodiment 1 of this invention. It is a block diagram which shows schematic structure of the self-position estimation part in the parking assistance apparatus by Embodiment 1 of this invention. It is a block diagram which shows schematic structure of the vehicle condition detection part in the parking assistance apparatus by Embodiment 1 of this invention. It is a block diagram which shows schematic structure of the vehicle condition detection part in the parking assistance apparatus by Embodiment 2 of this invention. It is a block diagram which shows schematic structure of the vehicle condition detection part in the parking assistance apparatus by Embodiment 3 of this invention. It is a block diagram which shows schematic structure of the vehicle condition detection part in the parking assistance apparatus by Embodiment 4 of this invention. It is a block diagram which shows schematic structure of the vehicle condition detection part in the parking assistance apparatus by Embodiment 5 of this invention. It is a block diagram which shows schematic structure of the parking assistance apparatus by Embodiment 6 of this invention. It is a block diagram which shows schematic structure of the self-position estimation part in the parking assistance apparatus by Embodiment 6 of this invention. It is a figure for demonstrating the own vehicle position and driving | running route at the time of parallel parking in the parking assistance apparatus by Embodiment 6 of this invention. It is a block diagram which shows schematic structure of the self-position estimation part in the parking assistance apparatus by Embodiment 7 of this invention. It is a block diagram which shows schematic structure of the yaw angle noise removal part in the parking assistance apparatus by Embodiment 7 of this invention.

Embodiment 1 FIG.
The first embodiment will be described below with reference to the drawings.
1 is a block diagram showing a schematic configuration of a parking assistance apparatus according to Embodiment 1 of the present invention.
In FIG. 1, the parking assistance device is configured as follows.
The parking support start determination unit 1 outputs a parking support start signal when starting parking support of the own vehicle. The self-position estimation unit 2 calculates the own vehicle position and the own vehicle attitude angle with the position when the parking assistance start signal is output as the reference position. The parking space detection unit 3 detects a parking space where the own vehicle can be parked, and calculates the position of the parking space with respect to the reference position.
The guide route calculation unit 4 calculates a guide route that can guide the host vehicle to the position of the parking space from the host vehicle position and the host vehicle attitude angle estimated by the host position estimation unit 2. The target steering angle calculation unit 5 calculates a target steering angle to be steered by the host vehicle from the guidance route. The steering angle detector 6 measures the current steering angle of the steering.
The electric power steering 7 can be controlled such that the steering angle matches the target steering angle.

FIG. 2 is a block diagram showing a schematic configuration of the self-position estimating unit in the parking assist apparatus according to Embodiment 1 of the present invention.
In FIG. 2, the self-position estimation unit 2 is configured as follows.
The yaw rate detector 8 detects the yaw rate of the vehicle. There are a plurality of wheel speed detectors 9, which respectively detect at least the left and right wheel speeds and the left and right wheel movement distances of the front wheels or rear wheels of the host vehicle. The vehicle speed calculation unit 10 calculates the vehicle speed from the left and right wheel speeds of the front wheels or the rear wheels. The steering angle detector 6 measures the current steering angle of the steering. The vehicle situation detection unit 11 detects a vehicle situation during parking assistance.
The first yaw angle calculation unit 12 calculates the first yaw angle of the host vehicle from the yaw rate. The second yaw angle calculation unit 13 calculates the second yaw angle of the host vehicle from the left and right wheel movement distance of the front wheel or the rear wheel. The third yaw angle calculation unit 14 calculates the third yaw angle of the host vehicle from the steering angle and the vehicle speed.
The composite yaw angle calculator 15 adjusts the composite ratio of the first yaw angle, the second yaw angle, and the third yaw angle according to the peak value of the vibration of the vehicle body as the vehicle situation, and calculates the composite yaw angle. . The own vehicle position / posture angle calculation unit 16 calculates the position and posture angle of the own vehicle from the vehicle speed and the combined yaw angle.

FIG. 3 is a block diagram showing a schematic configuration of the vehicle state detection unit in the parking assistance apparatus according to Embodiment 1 of the present invention.
3, reference numerals 11 to 15 are the same as those in FIG. FIG. 3 shows a configuration of the vehicle state detection unit 11, and the vehicle body vibration detection unit 17 detects the vibration of the vehicle body. The vehicle body vibration peak value calculation unit 18 calculates the peak value of the vehicle body vibration from the output of the vehicle body vibration detection unit 17.

Next, the operation will be described.
The parking support start determination unit 1 determines the timing for starting parking support. As a criterion for determining the start timing of the parking support, there is a method using a switch that the driver presses at the start of parking, or a method of determining the timing when the vehicle speed becomes equal to or less than a certain vehicle speed as the start of parking support.
These are merely examples, and other methods may be used as long as the parking start timing can be determined.

Next, the self-position estimation unit 2 estimates the position and posture angle of the vehicle after the start of parking support, using the position where the parking support start signal is received from the parking support start determination unit 1 as a reference position.
Here, as a method for estimating the position and posture angle of the own vehicle, a method called dead reckoning that is estimated from a wheel speed sensor and a yaw rate sensor is used.
As an example of dead reckoning, the yaw angle is calculated by detecting the moving distance from the wheel speed sensor and further integrating the yaw rate sensor every sampling time.
Here, as an example of the yaw angle calculation method, the integration of the yaw rate sensor is given as an example, but other methods such as an integration method for calculating the yaw rate obtained from the vehicle speed and the steering angle, or the difference between the moving distances of the left and right wheels. There is also a method of calculating from the above.
After calculating the yaw angle by the above method, the position of the own vehicle is obtained.
For example, if the traveling direction of the vehicle is the x axis and the lateral direction is the y axis, the vehicle position (x, y) from the reference position is expressed as follows.
x = L · sin (γ), y = L · cos (γ). Here, L is the moving distance, and γ is the yaw angle. By using such a method, it is possible to estimate the position and orientation of the host vehicle.

Next, the process of the parking space detection part 3 is demonstrated.
The parking space detection unit 3 detects a parking space around the host vehicle using an in-vehicle sensor, and calculates the position of the parking space with respect to the reference position determined by the self position estimation unit 2.
As an example of the in-vehicle sensor, an ultrasonic sonar is used. The ultrasonic sonar can measure the distance to the obstacle based on the time it takes for the ultrasonic sonar to reflect the reflected wave from the time when the ultrasonic wave is transmitted and to receive the reflected wave. .
By installing this ultrasonic sonar on the side of the vehicle and obtaining the distance from the side of the vehicle to the obstacle, the vehicle can detect the parking space on the side of the vehicle while the vehicle is running, The position of the parking space is calculated from the own vehicle position and the own vehicle attitude angle.
In the above description, the ultrasonic sonar is used as an example of the vehicle-mounted sensor. However, other vehicle-mounted sensors may be used as long as the parking space can be detected, such as a camera that reflects the periphery of the vehicle.

As described above, the position of the obstacle vehicle is calculated based on the position of the vehicle and the distance from the ultrasonic sonar.
Here, in the case of a rough road with a large unevenness on the road surface, noise is superimposed on the yaw rate, resulting in an error in the position of the vehicle, so even if the distance to the obstacle vehicle can be detected correctly, as a result The estimated position of the obstacle vehicle is different from the actual position. For this reason, the influence of noise superimposed on the yaw rate is significant.

Next, the process of the guidance route calculation unit 4 will be described.
The guide route calculation unit 4 moves from the own vehicle position / posture angle (own vehicle position and own vehicle posture angle) estimated by the own position estimation unit 2 to the position of the parking space detected by the parking space detection unit 3. Calculate the guidance route that can guide.
Based on the positional relationship between the vehicle position / posture angle and the parking space, the target parking position is subject to the target parking position set in the obstacle vehicle from the own vehicle position under the restriction condition that avoids the obstacle vehicle. The guidance route to reach is calculated.
Therefore, in order to calculate the guidance route, at least the own vehicle position / posture angle and the position and posture angle of the obstacle vehicle are required, that is, it can be said that the guide route using the yaw rate as an internal variable is calculated. .

Next, the process of the target steering angle calculation unit 5 will be described.
The target steering angle calculation unit 5 calculates a target curvature necessary for traveling along the guidance route from the parking guidance route calculated by the guidance route calculation unit 4, and the steering of the host vehicle is steered from the target curvature. The target steering angle to be calculated is calculated.
Here, the target curvature indicates the reciprocal of the turning radius of the own vehicle. There is a theoretical formula that defines the relationship between the target curvature and the target steering angle (formulas (1) and (2)). (Source: Masato Abe, Motor Movement and Control, 1st Edition, ISBN 978-4-501-41700-0 C3053)

  Here, ρ is the target curvature, V is the vehicle traveling speed, A is the stability factor, l is the vehicle wheel base, δ is the actual front wheel steering angle, n is the steering gear ratio (front wheel actual steering angle / steering angle), θ Is the steering angle. The target steering angle is calculated from the target curvature by using the above-described theoretical formulas (Formulas (1) and (2)).

Next, processing of the steering angle detection unit 6 will be described.
The steering angle detector 6 measures the current steering angle in the steering of the host vehicle. As a detection method, the steering angle of the steering is directly measured using a steering angle sensor.
The electric power steering 7 controls the steering of the vehicle so that the steering angle coincides with the target steering angle calculated by the target steering angle calculation unit 5 and performs automatic steering. The electric power steering 7 mainly measures a steering torque when the driver steers the steering by a torque sensor (not shown), and generates an assist torque for assisting the steering torque according to the steering torque. Function.
On the other hand, in parking assistance, it is not necessary to assist the driver's steering, and the parking assistance device automatically steers the steering. That is, the electric power steering 7 is feedback-controlled by the steering angle such that the steering angle follows the target steering angle.

Next, the self-position estimation unit 2 shown in FIG. 2 will be described in detail.
The yaw rate detector 8 detects the yaw rate of the host vehicle using a yaw rate sensor. The wheel speed detection unit 9 detects the left and right wheel speeds and the left and right wheel movement distances of the rear wheels, which are dependent wheels of the host vehicle, using a wheel speed sensor. The vehicle speed calculation unit 10 obtains an average value of the left and right wheel speeds and uses this value as the vehicle speed of the host vehicle.

The first yaw angle calculation unit 12 calculates the yaw angle of the host vehicle from the yaw rate detected by the yaw rate detection unit 8, and sets this yaw angle as the first yaw angle. The first yaw angle is calculated by integrating the yaw rate detected using the yaw rate sensor every sampling time.
The first yaw angle γ ₁ when the yaw rate detected by the yaw rate detection unit 8 is ω ₁ is obtained by Expression (3).

The first yaw angle can be easily calculated because the signal required for calculating the yaw angle is only the output of the yaw rate sensor.
However, since the yaw angle is calculated by integrating the output of the yaw rate sensor, if the yaw rate includes noise, an error accumulates in the calculated yaw angle. For this reason, the reliability of yaw angle calculation is reduced.
For example, when traveling on a rough road at a high vehicle speed, noise is superimposed on the output of the yaw rate sensor, so an error accumulates in the yaw angle calculated by integrating this yaw rate.

The second yaw angle calculation unit 13 calculates the yaw angle of the host vehicle from the left and right wheel movement distances detected by the wheel speed detection unit 9, and sets this yaw angle as the second yaw angle. The second yaw angle is calculated from the difference between the left and right wheel movement distances on the left and right sides of the vehicle.
Here, the wheel speed sensor detects a pulse every time the wheel rotates a certain distance, and counts the pulse to calculate the moving distance of the wheel and the wheel speed. The second wheel when the dependent wheel of the host vehicle is the rear wheel, the moving distance of the right wheel detected by the wheel speed sensor of the rear wheel is l _wr , the moving distance of the left wheel is l _wl , and the distance between the left and right wheels is d The yaw angle γ ₂ can be obtained from Equation (4).

Since the second yaw angle can be directly calculated without using integration, an error due to yaw rate integration does not accumulate unlike the first yaw angle. Therefore, when the vehicle speed is high, the yaw angle calculation accuracy is less likely to be lower than the first yaw angle.
However, during sudden acceleration / deceleration, an error occurs between the wheel speed sensor value and the actual wheel movement distance, which may reduce the reliability of yaw angle calculation.

The third yaw angle calculation unit 14 calculates the yaw angle of the host vehicle from the steering angle detected by the steering angle detection unit 6 and the vehicle speed calculated by the vehicle speed calculation unit 10, and uses this yaw angle as the third yaw angle. And The third yaw angle is calculated using the vehicle speed calculated from the actual steering angle of the front tire calculated from the steering angle and the average value of the left and right wheel speeds, and the calculated yaw rate is taken every sampling time. It is calculated by integrating to.
The third yaw angle γ ₃ when the front wheel actual steering angle calculated from the steering angle θ is δ, the vehicle speed calculated from the average of the left and right wheel speeds of the rear wheel of the host vehicle is V, and the wheel base is l is Obtained in (5).

Since the third yaw angle is calculated from the steering angle of the steering wheel, the yaw angle is stable when the steering angle is small, such as when traveling straight ahead. Therefore, there is a feature that a yaw angle with high accuracy can be calculated.
However, during automatic steering, noise may occur in the steering angle due to the influence of power steering control, and the yaw angle calculation accuracy may be reduced.

As described above, in the first embodiment, there are three types of yaw angle calculation methods represented by Expression (3) to Expression (5), and the characteristics of each method have been described.
If the above-described case where the yaw angle accuracy is lowered can be excluded, the yaw angle can always be calculated with high accuracy.
The following describes a technique that can reduce the influence of the accuracy reduction so that the yaw angle accuracy does not decrease using the vehicle state detection unit 11.

  The vehicle status detection unit 11 detects the vehicle status during parking assistance. Examples of the vehicle situation include the peak value and frequency of vehicle body vibration, the magnitude of vehicle speed and acceleration, and the magnitude of the steering angle. Details of these will be described later.

Based on the vehicle situation, the composite yaw angle calculation unit 15 adjusts the composite ratio of the first, second, and third yaw angles to calculate the composite yaw angle.
The composite yaw angle γ _sum when the composite ratio with respect to the first yaw angle is K ₁ , the composite ratio with respect to the second yaw angle is K ₂ , and the composite ratio with respect to the third yaw angle is K ₃ is expressed by Equation (6). It is obtained at.

However, the condition shown in Formula (7) is satisfied in the synthesis ratio (K ₁ , K ₂ , K ₃ ) of each yaw angle.

By adjusting the composite ratio of the first yaw angle, the second yaw angle, and the third yaw angle according to the vehicle situation, for example, the influence of vehicle body vibrations on bad roads in yaw angle calculation is suppressed, and more A highly accurate synthetic yaw angle can be calculated.
As a result, the self-position estimation accuracy is increased, and parking assistance to the target parking space can be performed more accurately.

As an example of the vehicle situation, the peak of vehicle body vibration is used as a criterion for yaw angle synthesis.
When traveling on a rough road, there is a problem in that the yaw rate acquired by the yaw rate sensor is caused by an error of the vehicle body and the yaw angle calculation accuracy is lowered.
Therefore, by detecting the peak of vehicle body vibration and using this as the criterion for yaw angle synthesis, the degradation of the accuracy of calculation of the composite yaw angle due to vehicle body vibration is suppressed, and the reliability of the vehicle position and attitude angle during parking assistance is suppressed. Can be increased.

The vehicle body vibration is detected by a vibration sensor mounted on the vehicle. By attaching the vibration sensor to the vehicle body, the vibration peak and frequency can be detected.
By using the vibration sensor to detect the peak value of the vehicle's body vibration, and using this value as the criterion for determining the yaw angle composition ratio, the yaw angle that causes errors when large body vibrations occur on rough roads. By reducing the composite ratio, it is possible to suppress the influence of vehicle body vibration in the composite yaw angle calculation.
For example, a yaw angle that does not include an error due to noise superimposed on the yaw rate sensor output value is synthesized by setting a synthesis ratio of (K ₁ = 0, K ₂ = 0.5, K ₃ = 0.5). Can do.

According to the first embodiment, even if the accuracy of the sensor output decreases due to the influence of the vehicle situation such as the vehicle body vibration that occurs on the rough road, the yaw rate, the steering angle, and the left and right wheel movement distances are used as the basis for three different detection values. It is possible to always maintain high yaw angle calculation accuracy by changing the combined ratio of yaw angles calculated in accordance with the road surface condition and the vehicle body condition.
By using the synthetic yaw angle with high calculation accuracy for self-position estimation, the calculation accuracy of the vehicle position and the vehicle attitude angle is improved, and the parking accuracy is improved.

Embodiment 2. FIG.
The second embodiment will be described below with reference to the drawings.
In the first embodiment, the vehicle condition detection unit 11 adjusts the composite ratio of the composite yaw angle based on the peak value of the vehicle body vibration.
However, the body vibration has a high or low frequency depending on the traveling speed of the vehicle or the unevenness of the road surface, and the influence on the calculation of the first, second, and third yaw angles differs depending on the frequency of the body vibration.
Therefore, the second embodiment detects the frequency of the vehicle body vibration as the vehicle situation, and uses this as a criterion for the yaw angle synthesis, thereby solving the above-described problem and reducing the accuracy of the composite yaw angle calculation due to the vehicle body vibration. This improves the reliability of the vehicle position and posture angle during parking assistance.

FIG. 4 is a block diagram showing a schematic configuration of a vehicle state detection unit in the parking assistance apparatus according to Embodiment 2 of the present invention.
In FIG. 4, reference numerals 11 to 15 and 17 are the same as those in FIG. In FIG. 4, the vehicle situation detection unit 11 is provided with a vehicle body vibration frequency calculation unit 19 that calculates the frequency of vehicle body vibration.

  In the second embodiment, the vehicle condition detection unit 11 includes a vehicle body vibration detection unit 17 that detects the vibration of the vehicle body, and a vehicle body vibration frequency calculation unit 19 that calculates the frequency of the vehicle body vibration. The composite ratio of the first yaw angle, the second yaw angle, and the third yaw angle is changed according to the vibration frequency of the vehicle body.

The vehicle body vibration is detected by a vibration sensor mounted on the vehicle. By calculating the body vibration frequency and using the body vibration frequency as a criterion for determining the yaw angle composition ratio, the yaw angle ratio can be changed according to the frequency range of the vehicle vibration, and the influence of rough roads is suppressed. The yaw angle can be acquired.
In particular, when the body vibration frequency is high, high-frequency noise is generated in the outputs of the yaw rate sensor and the wheel speed sensor. For example, (K ₁ = 0.2, K ₂ = 0.2, K ₃ = 0.6) ), It is possible to synthesize a yaw angle that suppresses the influence of noise caused by a rough road that occurs in the yaw rate sensor or wheel speed sensor.

According to the second embodiment, it is possible to synthesize a yaw angle in which accumulation of errors due to high-frequency noise is suppressed by using vehicle vibration generated on a rough road, in particular, the frequency of vehicle vibration as a reference.
By using this synthetic yaw angle for self-position estimation, the calculation accuracy of the vehicle position and the vehicle attitude angle is improved, and a remarkable effect is obtained for improving the parking accuracy.

Embodiment 3 FIG.
The third embodiment will be described below with reference to the drawings.
In the second embodiment, the composite ratio of the composite yaw angle is adjusted in the vehicle state detection unit 11 with the frequency of the vehicle body vibration as a reference.
However, when traveling on rough roads, there is a problem that the calculation accuracy of the first, second, and third yaw angles varies depending on the vehicle speed.
For example, when the vehicle speed is low, the wheel rotates due to the unevenness of the road surface, and an error is likely to occur in the wheel movement distance as compared with the case of traveling on a flat surface. Therefore, the calculation accuracy of the second yaw angle calculated based on the wheel movement distance is lowered.
Therefore, in the third embodiment, the above-described problems are solved, the deterioration of the composite yaw angle calculation accuracy due to the vehicle speed is suppressed, and the reliability of the own vehicle position and posture angle during parking assistance is improved.

FIG. 5 is a block diagram showing a schematic configuration of a vehicle state detection unit in the parking assistance apparatus according to Embodiment 3 of the present invention.
In FIG. 5, reference numerals 11 to 15 are the same as those in FIG. In FIG. 5, the vehicle condition detection unit 11 is provided with the same vehicle speed calculation unit 10 as in FIG. 2, and the combined yaw angle calculation unit 15 determines the first yaw angle, the second yaw angle, and the third yaw angle depending on the vehicle speed. The composition ratio of corners was changed.

The vehicle speed is calculated by averaging the left and right wheel speeds of the vehicle rear wheel detected by the wheel speed detection unit 9.
If this vehicle speed is used as a criterion for determining the yaw angle composition ratio, when the vehicle speed is high, the ratio of the second yaw angle based on the wheel speed with high accuracy at the time of calculation is increased (for example, K ₁ = 0.2, K ₂ = 0.6, K ₃ = 0.2) When the vehicle speed is low, the ratio of the second yaw angle that is easily affected by road surface unevenness is reduced (for example, K ₁ = 0.4, K ₂ = 0.2, K ₃ = 0.4), it is possible to suppress a decrease in yaw angle calculation accuracy due to the vehicle speed when traveling on a rough road.

According to the third embodiment, by using the vehicle speed as a reference for adjusting the yaw angle synthesis ratio, it is possible to calculate a synthesized yaw angle with high calculation accuracy when the vehicle speed is high and when the vehicle speed is low.
By using this synthetic yaw angle for self-position estimation, the calculation accuracy of the vehicle position and the vehicle attitude angle is improved, and a remarkable effect is obtained for improving the parking accuracy.

Embodiment 4 FIG.
The fourth embodiment will be described below with reference to the drawings.
In the third embodiment, the vehicle condition detection unit 11 adjusts the composite ratio of the composite yaw angle based on the vehicle speed.
However, when the vehicle performs acceleration / deceleration, there is a problem that a difference occurs in calculation accuracy of the first, second, and third yaw angles.
For example, during sudden acceleration / deceleration, an error may occur between the wheel speed sensor value and the actual wheel movement distance, which may reduce the calculation accuracy of the second yaw angle.
Therefore, in the fourth embodiment, the above-described problem is solved, the deterioration of the calculation accuracy of the composite yaw angle due to acceleration / deceleration of the vehicle body is suppressed, and the reliability of the own vehicle position and posture angle during parking assistance is improved. .

FIG. 6 is a block diagram showing a schematic configuration of a vehicle state detection unit in the parking assistance apparatus according to Embodiment 4 of the present invention.
In FIG. 6, reference numerals 11 to 15 are the same as those in FIG. In FIG. 6, the vehicle situation detection unit 11 is provided with a vehicle body acceleration calculation unit 20 that calculates the acceleration of the vehicle body. In the combined yaw angle calculation unit 15, the first yaw angle and the second yaw angle are determined based on the vehicle body acceleration. The composition ratio of the angle and the third yaw angle was changed.

The vehicle body acceleration can be calculated by differentiating the average of the left and right wheel speeds of the rear wheel of the host vehicle detected by the wheel speed detection unit 9.
By using this acceleration as a criterion for determining the yaw angle composition ratio, it is possible to suppress a decrease in yaw angle calculation accuracy during acceleration / deceleration.
For example, the accuracy of the second yaw angle based on the wheel speed decreases during acceleration due to a sudden increase in accelerator pedal or deceleration due to a sudden brake. Therefore, by reducing the ratio of the second yaw angle (for example, K ₁ = 0.4, K ₂ = 0.2, K ₃ = 0.4), adverse effects due to acceleration / deceleration can be suppressed.
Although the vehicle body acceleration is calculated from the wheel speed here, it may be calculated by other methods such as an acceleration sensor as long as the vehicle body acceleration can be calculated.

According to the fourth embodiment, by using the vehicle body acceleration as a reference for adjusting the yaw angle synthesis ratio, it is possible to calculate the synthesized yaw angle that suppresses a decrease in calculation accuracy during acceleration / deceleration.
By using this synthetic yaw angle for self-position estimation, the calculation accuracy of the vehicle position and the vehicle attitude angle is improved, and a remarkable effect is obtained for improving the parking accuracy.

Embodiment 5. FIG.
The fifth embodiment will be described below with reference to the drawings.
In the fourth embodiment, the vehicle condition detection unit 11 adjusts the composite ratio of the composite yaw angle based on the vehicle body acceleration.
However, there is a problem that the calculation accuracy of the first, second, and third yaw angles varies depending on the steering angle of the vehicle. For example, when the steering angle is small, such as when traveling straight ahead, the yaw angle is stable, and the calculation accuracy of the third yaw angle is high.
Therefore, in the fifth embodiment, the above-mentioned problem is solved, the deterioration of the calculation accuracy of the composite yaw angle due to the steering angle is suppressed, and the reliability of the vehicle position and posture angle during parking assistance is improved.

FIG. 7 is a block diagram showing a schematic configuration of a vehicle state detection unit in the parking assistance apparatus according to Embodiment 5 of the present invention.
In FIG. 7, reference numerals 11 to 15 are the same as those in FIG. In FIG. 7, the vehicle state detection unit 11 is provided with the same steering angle detection unit 6 as in FIG. 2. In the composite yaw angle calculation unit 15, the composite ratio of the first yaw angle, the second yaw angle, and the third yaw angle is changed according to the steering angle.

By using the magnitude of the steering angle measured by the steering angle detector 6 as a criterion for determining the yaw angle composition ratio, the yaw angle can be calculated in accordance with the steering of the host vehicle.
For example, when the magnitude of the steering angle is small, the vehicle is almost straight and the steering angle is stabilized, so the ratio of the third yaw angle based on the steering angle is increased (for example, K ₁ = 0. 2, K ₂ = 0.2, K ₃ = 0.6), it is possible to improve the yaw angle calculation accuracy during straight traveling.

According to the fifth embodiment, by using the magnitude of the steering angle as a reference for adjusting the yaw angle synthesis ratio, the synthesized yaw angle with a high calculation accuracy during straight traveling with a small steering angle is calculated. be able to.
By using this synthetic yaw angle for self-position estimation, the calculation accuracy of the vehicle position and the vehicle attitude angle is improved, and a remarkable effect is obtained for improving the parking accuracy.

Embodiment 6 FIG.
The sixth embodiment will be described below with reference to the drawings.
In the fifth embodiment, the vehicle condition detection unit 11 adjusts the composite ratio of the composite yaw angle based on the steering angle.
However, there is a problem in that the calculation accuracy of the first, second, and third yaw angles differs because the vehicle speed and the size of the steering angle are characteristic depending on the parking mode that represents the parking sequence during parking assistance. .
For example, when automatic steering is performed by the electric power steering 7, the calculation speed of the second yaw angle is reduced because the vehicle speed is low. Further, since the vehicle travels straight while the parking space is detected by the parking space detection unit 3, the steering angle becomes small. Therefore, the calculation accuracy of the third yaw angle is increased.
Thus, since the vehicle speed and the steering angle differ depending on the parking mode, the calculation accuracy of the first, second, and third yaw angles differs.
Therefore, in the sixth embodiment, the above-described problems are solved, the deterioration of the composite yaw angle calculation accuracy due to the parking mode is suppressed, and the reliability of the own vehicle position and posture angle during parking assistance is improved.

FIG. 8 is a block diagram showing a schematic configuration of a parking assistance apparatus according to Embodiment 6 of the present invention.
In FIG. 8, reference numerals 1 to 7 are the same as those in FIG. The parking support device of FIG. 8 includes a parking mode management unit 21 that manages a parking mode representing a parking sequence during parking support.

FIG. 9 is a block diagram showing a schematic configuration of the self-position estimating unit in the parking assist apparatus according to Embodiment 6 of the present invention.
9, reference numerals 2, 6, and 8 to 16 are the same as those in FIG. In FIG. 9, the output of the parking mode management unit 21 is input to the composite yaw angle calculation unit 15.

FIG. 10 is a diagram for explaining the own vehicle position and travel route during parallel parking in the parking assist device according to Embodiment 6 of the present invention.
In FIG. 10, an obstacle vehicle 100 is a vehicle that becomes two obstacles that are already parked. A traveling route when the host vehicle 101 is parked in parallel in the parking space between the two obstacle vehicles 100 by parking assistance is shown.
A travel route from the vehicle position P1 at the start of parking assistance to the vehicle position P2 at the start of automatic steering is defined as L1. A travel route from the own vehicle position P2 at the start of automatic steering to the own vehicle position P3 at the completion of parking is defined as L2.

In addition to the parking assistance device of the first embodiment, the sixth embodiment has a parking mode management unit 21 that manages a parking mode that represents a parking sequence during parking assistance.
As shown in FIG. 9, the combined yaw angle calculation unit 15 changes the combined ratio of the first yaw angle, the second yaw angle, and the third yaw angle depending on the parking mode.

By using the parking mode as a criterion for determining the yaw angle composition ratio, it is possible to acquire a highly accurate composite yaw angle that matches the steering angle and vehicle speed conditions in each mode.
First, the parking mode will be described based on FIG. 10 showing a travel route during parallel parking.

FIG. 10 shows a travel route when the host vehicle 101 is parked in parallel in the parking space between the two obstacle vehicles 100 that are already parked.
A travel route from the vehicle position P1 at the start of parking assistance to the vehicle position P2 at the start of automatic steering is L1, and the parking space is detected by the parking space detector 3 in the travel route L1. At this time, the own vehicle 101 travels straight.
Further, a travel route from the own vehicle position P2 at the start of automatic steering to the own vehicle position P3 at the completion of parking is set to L2. In this travel route L2, automatic steering is performed by the electric power steering 7.
Here, the parking mode in the travel route L1 is defined as a parking space detection sequence, and the parking mode in the travel route L2 is defined as an automatic steering sequence.

In the parking space detection sequence in the parking mode, since the vehicle travels straight, the vehicle speed is relatively high and the steering angle is small in the speed during parking assistance. Therefore, the composite ratio of the second yaw angle based on the wheel speed and the third yaw angle based on the steering angle is increased (for example, K ₁ = 0.2, K ₂ = 0.4, K ₃ = 0. 4) Thus, it is possible to acquire a highly accurate synthetic yaw angle.
Further, in the automatic steering sequence, the vehicle speed is lower and the steering angle is larger than when traveling straight ahead. Therefore, by increasing the composite ratio of the first yaw angle based on the yaw rate (for example, K ₁ = 0.6, K ₂ = 0.2, K ₃ = 0.2), a highly accurate composite yaw angle can be obtained. Can be acquired.

According to the sixth embodiment, by adjusting the yaw angle synthesis ratio with reference to the parking mode, a highly accurate synthesized yaw angle can always be acquired during parking assistance.
By using this synthetic yaw angle for self-position estimation, the calculation accuracy of the vehicle position and the vehicle attitude angle is improved, and a remarkable effect is obtained for improving the parking accuracy.

  In addition, although parallel parking was demonstrated here, also in the case of parallel parking, a yaw angle calculation precision can be improved similarly by adjusting a synthetic | combination ratio on the basis of parking mode.

In the above-described embodiments, specific numerical values of the combined ratios (K ₁ , K ₂ , K ₃ ) of the first, second, and third yaw angles are shown. If the ratio is set according to the characteristics of the first, second, and third yaw angles as shown in the respective embodiments in accordance with the vehicle situation within the range that satisfies the condition of (7), another A numerical value is also acceptable.

In the above-described embodiments, the yaw angles are synthesized based on the first, second, and third yaw angles, but any one of (K ₁ , K ₂ , K ₃ ) The ratio may be set to 0, and two of the three may be used for the yaw angle synthesis, or a method of switching so that any one of the three may be the synthesized yaw angle may be used.

Embodiment 7 FIG.
The seventh embodiment will be described below with reference to the drawings.
In the composite yaw angle calculation unit 15 of the first to sixth embodiments, the first and second are based on the vehicle status detected by the vehicle status detection unit 11 or the parking mode managed by the parking mode management unit 21. The composite yaw angle was calculated by adjusting the composite ratio of the third yaw angle.
However, when noise is generated due to a bad road in any of the first, second, and third yaw angles, noise is also generated in the combined yaw angle, and the calculation accuracy of the combined yaw angle is high. There is a problem of lowering.
Therefore, in the seventh embodiment, the above-described problems are solved, the deterioration of the composite yaw angle calculation accuracy due to noise is suppressed, and the reliability of the own vehicle position and posture angle during parking assistance is improved.

FIG. 11 is a block diagram showing a schematic configuration of the self-position estimating unit in the parking assist apparatus according to Embodiment 7 of the present invention.
In FIG. 11, reference numerals 2, 6, 8, 9, 11, 16 and 21 are the same as those in FIG. In FIG. 11, the synthesized yaw angle calculation unit 15 includes a yaw angle synthesis ratio adjustment unit 22 and a yaw angle noise removal unit 23. The yaw angle synthesis ratio adjustment unit 22 adjusts the synthesis ratio of the first, second, and third yaw angles noise-processed by the yaw angle noise removal unit 23 based on the vehicle situation, and calculates a composite yaw angle.

FIG. 12 is a block diagram showing a schematic configuration of a yaw angle noise removing unit in the parking assist apparatus according to Embodiment 7 of the present invention.
In FIG. 12, reference numerals 11 to 15, 21 to 23 are the same as those in FIG. FIG. 12 shows the configuration of the yaw angle noise removing unit 23.
The yaw angle noise removal unit 23 includes a first yaw rate calculation unit 24 that calculates a yaw rate from the first yaw angle calculated by the first yaw angle calculation unit 12, and a second yaw angle calculation unit 13 that calculates the second yaw angle calculation unit 13. From the second yaw rate calculation unit 25 that calculates the yaw rate from the yaw angle, the third yaw rate calculation unit 26 that calculates the yaw rate from the third yaw angle calculated by the third yaw angle calculation unit 14, and the first yaw rate A first yaw rate frequency detector 27 for detecting the frequency of the first yaw rate; a second yaw rate frequency detector 28 for detecting the frequency of the second yaw rate from the second yaw rate; and a third yaw rate from the third yaw rate. A third yaw rate frequency detector 29 for detecting the frequency of the first yaw angle and a first yaw angle for calculating a noise removal filter for the first yaw angle and removing noise of the first yaw angle The noise removal unit 30, the noise removal filter for the second yaw angle are calculated, the second yaw angle noise removal unit 31 for removing the noise of the second yaw angle, and the noise removal filter for the third yaw angle are calculated. And a third yaw angle noise removing unit 32 for removing noise of the third yaw angle.

The first yaw rate calculator 24 differentiates the first yaw angle calculated by the first yaw angle calculator 12 to calculate the first yaw rate. The first yaw rate frequency detection unit 27 detects the frequency of the first yaw rate. The first yaw angle noise removal unit 30 adjusts the cutoff frequency of the noise removal filter based on the frequency of the first yaw rate, and performs noise removal of the first yaw angle by the noise removal filter.
For example, when the purpose is to remove high-frequency noise, noise having a higher frequency than the cut-off frequency can be removed by setting the Nth order frequency as the cut-off frequency in the frequency component of the first yaw angle. Here, the value of N may be adjusted according to the test result by performing a parking assistance test.

  In the second and third yaw angles, noise removal is performed in the same manner. Thus, by calculating the cut-off frequency according to the frequencies of the first, second, and third yaw angles, it is possible to always calculate a yaw angle with less noise.

According to the seventh embodiment, before the first, second, and third yaw angles are synthesized, noise is removed based on the frequency of each yaw rate, so that the synthesized yaw is based on the original signal of each yaw angle. It is possible to acquire a synthesized yaw angle with higher accuracy than when calculating the angle.
By using this synthetic yaw angle for self-position estimation, the calculation accuracy of the vehicle position and the vehicle attitude angle is improved, and a remarkable effect is obtained for improving the parking accuracy.

In the first to seventh embodiments, the method for improving the self-position estimation accuracy by improving the yaw angle detection accuracy by using various methods has been described. The methods of the first to seventh embodiments. May be used in combination with priorities.
The combination pattern and the priority order may be set in advance for each destination when the vehicle is shipped, or may be actively changed according to the surrounding environment at the start of parking support even after the vehicle is shipped.

  It should be noted that the present invention can be freely combined with each other within the scope of the invention, and each embodiment can be appropriately modified or omitted.

DESCRIPTION OF SYMBOLS 1 Parking assistance start determination part, 2 Self-position estimation part, 3 Parking space detection part, 4 Guide route calculation part, 5 Target steering angle calculation part, 6 Steering angle detection part, 7 Electric power steering, 8 Yaw rate detection part, 9 Wheel Speed detection unit, 10 vehicle speed calculation unit, 11 vehicle condition detection unit, 12 first yaw angle calculation unit, 13 second yaw angle calculation unit, 14 third yaw angle calculation unit, 15 composite yaw angle calculation unit, 16 own vehicle position Attitude angle calculation unit, 17 vehicle body vibration detection unit, 18 vehicle body vibration peak value calculation unit, 19 vehicle body vibration frequency calculation unit, 20 vehicle body acceleration calculation unit, 21 parking mode management unit, 22 yaw angle synthesis ratio adjustment unit, 23 yaw angle noise Remover, 24 First yaw rate calculator, 25 Second yaw rate calculator, 26 Third yaw rate calculator, 27 First yaw rate frequency detector, 28 Second yaw rate frequency detector, 29 Third -Rate frequency detection unit, 30 1st yaw angle noise removal unit, 31 2nd yaw angle noise removal unit, 32 3rd yaw angle noise removal unit, 100 obstacle vehicle, 101 own vehicle, P1 own vehicle position at the start of parking support , P2 Auto-vehicle position at the start of automatic steering, P3 Auto-vehicle position at completion of parking, L1 Traveling path during parking space detection, L2 Traveling path during automatic steering

Claims (9)

A parking assistance device configured to provide parking assistance,
A steering angle detector for detecting the steering angle of the vehicle,
And a self-position estimation unit that calculates the position and posture angle of the vehicle using the steering angle detected by the steering angle detection unit, with the position of the vehicle when the parking assistance is started as a reference position,
The self-position estimation unit
A yaw rate detector for detecting the yaw rate of the vehicle;
A wheel speed detection unit for detecting the left and right wheel speeds and the left and right wheel movement distances of the front wheel or rear wheel of the host vehicle;
A vehicle speed calculation unit that calculates a vehicle speed based on the left and right wheel speeds of the front wheels or rear wheels detected by the wheel speed detection unit;
A vehicle status detection unit for detecting a vehicle status during parking assistance;
A first yaw angle calculator that calculates a first yaw angle of the host vehicle based on the yaw rate detected by the yaw rate detector;
A second yaw angle calculation unit that calculates a second yaw angle of the host vehicle based on the left and right wheel movement distance of the front wheel or rear wheel detected by the wheel speed detection unit;
A third yaw angle calculator for calculating a third yaw angle of the host vehicle based on the steering angle detected by the steering angle detector and the vehicle speed calculated by the vehicle speed calculator;
Based on the vehicle status detected by the vehicle status detection unit, the combined yaw angle is calculated by adjusting the combined ratio of the first yaw angle, the second yaw angle, and the third yaw angle. A calculation unit;
A parking assistance device comprising: a vehicle position / posture angle calculation unit that calculates a position and a posture angle of the vehicle based on the vehicle speed and the combined yaw angle calculated by the combined yaw angle calculation unit. The vehicle status detection unit
A vehicle body vibration detection unit for detecting vibrations of the vehicle body of the vehicle;
A vehicle body vibration peak value calculating unit that calculates a vehicle body vibration peak value detected by the vehicle body vibration detecting unit;
The composite yaw angle calculation unit is configured to calculate the first yaw angle, the second yaw angle, and the third yaw angle based on the peak value of the vehicle body vibration calculated by the vehicle body vibration peak value calculation unit. The parking assistance device according to claim 1, wherein the combination ratio is adjusted. The vehicle status detection unit
A vehicle body vibration detection unit for detecting vibrations of the vehicle body of the vehicle;
A vehicle body vibration frequency calculating unit that calculates a frequency of vibration of the vehicle body detected by the vehicle body vibration detecting unit;
The composite yaw angle calculation unit is a composite ratio of the first yaw angle, the second yaw angle, and the third yaw angle based on the vibration frequency of the vehicle body calculated by the vehicle body vibration frequency calculation unit. The parking assist device according to claim 1, wherein the parking assist device is adjusted. The vehicle state detection unit includes the vehicle speed calculation unit,
The composite yaw angle calculator adjusts a composite ratio of the first yaw angle, the second yaw angle, and the third yaw angle based on the vehicle speed calculated by the vehicle speed calculator. The parking assistance device according to claim 1. The vehicle status detection unit
A vehicle body acceleration calculating unit for calculating the acceleration of the vehicle body;
The composite yaw angle calculation unit adjusts a composite ratio of the first yaw angle, the second yaw angle, and the third yaw angle based on the vehicle body acceleration calculated by the vehicle body acceleration calculation unit. The parking support apparatus according to claim 1, wherein The vehicle state detection unit includes the steering angle detection unit,
The composite yaw angle calculation unit adjusts a composite ratio of the first yaw angle, the second yaw angle, and the third yaw angle based on the steering angle detected by the steering angle detection unit. The parking support apparatus according to claim 1, wherein A parking mode management unit that manages a parking mode indicating a parking sequence during parking assistance,
The composite yaw angle calculation unit adjusts a composite ratio of the first yaw angle, the second yaw angle, and the third yaw angle based on the parking mode. Parking assistance device. The synthetic yaw angle calculator is
Before calculating the composite yaw angle, a yaw angle noise removing unit that removes noise of the first yaw angle, the second yaw angle, and the third yaw angle;
8. A yaw angle synthesis ratio adjusting unit that adjusts a synthesis ratio of the first yaw angle, the second yaw angle, and the third yaw angle. The parking assistance device according to one item. The yaw angle noise removing unit is
A first yaw angle noise removing unit that removes noise of the first yaw angle by a noise removal filter having a cutoff frequency set according to the frequency of the yaw rate calculated from the first yaw angle;
A second yaw angle noise removing unit that removes noise of the second yaw angle by a noise removal filter having a cutoff frequency set according to the frequency of the yaw rate calculated from the second yaw angle;
A third yaw angle noise removing unit that removes the noise of the third yaw angle by a noise removal filter having a cutoff frequency set according to the frequency of the yaw rate calculated from the third yaw angle. The parking support device according to claim 8, wherein: