Steering control method and steering control device

Abstract

A steering control device according to the present invention: acquires a distance from a vehicle to an obstacle, the distance being detected by a distance detecting sensor; calculates a first target steering angle such that the shorter the distance is to an obstacle existing on the left side in the forward direction of the vehicle, the greater the steering angle is in a steering direction causing the vehicle to move away from the obstacle as the vehicle moves forward; calculates a second target steering angle such that the shorter the distance is to an obstacle existing on the right side in the forward direction of the vehicle, the greater the steering angle is in a steering direction causing the vehicle to move away from the obstacle as the vehicle moves forward; calculates a final steering angle by adding together the first and second target steering angles; and controls a steering wheel of the vehicle on the basis of the final steering angle.

Description

[Technical field]

[0001] The present invention relates to a steering control method and device for controlling the steering of a vehicle equipped with a distance detection sensor that detects the distance to an obstacle present around the vehicle. [Background technology]

[0002] Conventionally, a vehicle with a parking assistance function that allows a vehicle to be parked in a parking space by external operation is disclosed in Patent Document 1. In the vehicle with the parking assistance function disclosed in Patent Document 1, a vehicle user who is outside the vehicle moves the vehicle into the parking space by using a switch provided on the smart key. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2008-74296 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the conventional vehicle with parking assistance function described above, if an obstacle is detected while the vehicle is moving, the vehicle is stopped, which causes a problem that the vehicle cannot be moved smoothly.

[0005] Therefore, the present invention has been proposed in consideration of the above-mentioned situation, and has an object to provide a steering control method and device therefor that can smoothly move the vehicle while avoiding an obstacle even if an obstacle is detected while the vehicle is moving. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems, a steering control method and device according to one aspect of the present invention calculates a first target steering angle so that the steering angle in the steering direction in which the vehicle moves away from the obstacle as the vehicle travels increases as the distance to an obstacle on the left side of the vehicle's traveling direction decreases. On the other hand, a second target steering angle is calculated so that the steering angle in the steering direction in which the vehicle moves away from the obstacle as the vehicle travels increases as the distance to an obstacle on the right side of the vehicle's traveling direction decreases. Then, the first target steering angle and the second target steering angle are added to calculate a final steering angle, and the steered wheels of the vehicle are controlled based on the final steering angle. Effect of the Invention

[0007] According to the present invention, even if an obstacle is detected while the vehicle is moving, the vehicle can be moved smoothly while avoiding the obstacle. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a block diagram showing the configuration of a vehicle equipped with a steering control device according to one embodiment of the present invention. [Diagram 2] FIG. 2 is a diagram showing the arrangement of distance detection sensors in a vehicle equipped with a steering control device according to one embodiment of the present invention. [Diagram 3] FIG. 3 is a diagram for explaining a method of calculating a first target steering angle by the steering control device according to one embodiment of the present invention. [Figure 4] FIG. 4 is a diagram for explaining a method of calculating a second target steering angle by the steering control device according to one embodiment of the present invention. [Diagram 5] FIG. 5 is a flowchart showing the procedure of the steering control process performed by the steering control device according to one embodiment of the present invention. [Figure 6] FIG. 6 is a diagram for explaining a specific method of calculating the first target steering angle by the steering control device according to one embodiment of the present invention. [Figure 7] FIG. 7 is a diagram for explaining a specific method of calculating the second target steering angle by the steering control device according to one embodiment of the present invention. [Figure 8] FIG. 8 is a diagram showing a specific example of parameter values ​​used when the target steering angle is calculated by the steering control device according to one embodiment of the present invention. [Figure 9] FIG. 9 is a diagram showing a specific example of steering control performed by the steering control device according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the description of the drawings, the same parts are given the same reference numerals and detailed description will be omitted.

[0010] [Configuration of a vehicle equipped with a steering control device] Fig. 1 is a block diagram showing the configuration of a vehicle equipped with a steering control device according to this embodiment. As shown in Fig. 1, vehicle 100 is equipped with a steering control device 1, a distance detection sensor 3, a steering motor 5, and a remote control device 7. Vehicle 100 can be remotely controlled by a driver outside the vehicle using remote control device 7.

[0011] The distance detection sensor 3 is a sensor that detects the distance to an obstacle existing around the vehicle 100, and is composed of a left sensor LS and a right sensor RS. The left sensor LS is a sensor that detects the distance to an obstacle existing on the left side of the traveling direction of the vehicle 100, and is composed of a first left sensor LS1 and a second left sensor LS2. The right sensor RS is a sensor that detects the distance to an obstacle existing on the right side of the traveling direction of the vehicle 100, and is composed of a first right sensor RS1 and a second right sensor RS2.

[0012] As shown in FIG. 2, the first left sensor LS1 detects an obstacle present on the left side of the traveling direction when the vehicle 100 moves forward, and measures the distance D L The second left sensor LS2 is a sensor for detecting an obstacle on the left side of the vehicle 100 when the vehicle 100 is moving backwards, and for detecting the distance D to the obstacle. LThe second left sensor LS2 is installed at the right rear of the vehicle 100, but when the vehicle 100 is moving backward, it detects an obstacle on the left side of the traveling direction of the vehicle 100 moving backward, and therefore serves as a left sensor.

[0013] Furthermore, the first right sensor RS1 detects an obstacle present on the right side of the traveling direction when the vehicle 100 moves forward, and measures the distance D R The second right sensor RS2 is a sensor for detecting an obstacle on the right side of the vehicle 100 when the vehicle 100 is moving backwards, and measures the distance D R The second right sensor RS2 is installed on the left rear of the vehicle 100, and when the vehicle 100 is moving backward, it detects an obstacle on the right side of the traveling direction of the vehicle 100 moving backward, and therefore serves as a right sensor.

[0014] The left sensor LS and the right sensor RS are each composed of a sonar, and emit sound waves within different non-overlapping ranges within a predetermined range on the left side of the vehicle's traveling direction and a predetermined range on the right side of the vehicle's traveling direction, and detect the distance from the vehicle 100 to the obstacle based on the reflected waves from the obstacle. However, as long as the distance to the obstacle can be detected, a sensor other than sonar may be used, for example, a camera or a laser range finder. However, the left sensor LS and the right sensor RS only need to detect the distance from the vehicle 100 to the obstacle, and do not need to detect the position (coordinates) of the obstacle relative to the vehicle 100. Therefore, by using a sonar that can generally detect only the distance from the vehicle 100 to the obstacle, it is possible to configure the sensor at a lower cost than using a camera or a laser range finder that can detect the distance to the obstacle and the position of the obstacle.

[0015] The steering control device 1 controls the steered wheels of the vehicle 100 so as to avoid the obstacle, based on the distance from the vehicle 100 to the obstacle detected by the distance detection sensor 3. The steering control device 1 is mounted on the vehicle 100, and comprises an obstacle distance acquisition section 11, a target steering angle calculation section 13, a final steering angle calculation section 15, and a steering control section 17. The steering control of the steering control device 1 may be applied to the control of the steered wheels when the vehicle 100 is automatically parked in a parking space, or may be applied to the control of the steered wheels when the driver outside the vehicle parks the vehicle 100 by remote operation using the remote operation device 7.

[0016] The obstacle distance acquisition unit 11 acquires the distance from the vehicle 100 to an obstacle detected by the distance detection sensor 3. Specifically, when the vehicle 100 is moving forward, the obstacle distance acquisition unit 11 acquires the distance D from the first left sensor LS1 to an obstacle on the left side in the traveling direction. L and the distance D from the first right sensor RS1 to the obstacle on the right side of the traveling direction R When the vehicle 100 is moving backward, the obstacle distance acquisition unit 11 acquires a distance D from the second left sensor LS2 to an obstacle on the left side in the traveling direction (backward). L and the distance D from the second right sensor RS2 to the obstacle on the right side of the traveling direction (backward) R Get the.

[0017] The target steering angle calculation unit 13 calculates the first target steering angle and the second target steering angle based on the distance to the obstacle acquired by the obstacle distance acquisition unit 11. The first target steering angle is a target steering angle for avoiding an obstacle present on the left side of the traveling direction of the vehicle 100, and is a steering angle to the right when the vehicle 100 moves forward, and is a steering angle to the left when the vehicle 100 moves backward. The second target steering angle is a target steering angle for avoiding an obstacle present on the right side of the traveling direction of the vehicle 100, and is a steering angle to the left when the vehicle 100 moves forward, and is a steering angle to the right when the vehicle 100 moves backward. That is, both the first target steering angle and the second target steering angle are steering angles in a steering direction in which the vehicle moves away from the obstacle as the vehicle moves forward. The first target steering angle is calculated based only on the distance to the obstacle detected by the left sensor LS, and the second target steering angle is calculated based only on the distance to the obstacle detected by the right sensor RS. One of the first target steering angle and the second target steering angle is calculated as a positive value (a positive value whose absolute value increases as the steering angle increases), and the other is calculated as a negative value (a negative value whose absolute value increases as the steering angle increases).

[0018] Target steering angle calculation unit 13 calculates a first target steering angle so that the shorter the distance to an obstacle present on the left side of vehicle 100 in the traveling direction, the larger the steering angle in the direction away from the obstacle will be as vehicle 100 travels. Target steering angle calculation unit 13 also calculates a second target steering angle so that the shorter the distance to an obstacle present on the right side of vehicle 100 in the traveling direction, the larger the steering angle in the direction away from the obstacle will be as vehicle 100 travels.

[0019] For example, when vehicle 100 is moving forward and there is an obstacle on the left side of the traveling direction, the "steering angle in the turning direction in which the vehicle moves away from the obstacle as vehicle 100 moves forward" is a steering angle to the right. Therefore, the first target steering angle is calculated so that the steering angle to the right increases as the distance to the obstacle decreases. Conversely, when vehicle 100 is moving backward and there is an obstacle on the left side of the traveling direction (backward), the "steering angle in the turning direction in which the vehicle moves away from the obstacle as vehicle 100 moves forward" is a steering angle to the left. Therefore, the first target steering angle is calculated so that the steering angle to the left increases as the distance to the obstacle decreases.

[0020] Referring now to FIG. 3, a first target steering angle θ, which is a target steering angle for avoiding an obstacle present on the left side of the traveling direction of the vehicle 100, is L As shown in FIG. 3, the target steering angle calculation unit 13 calculates the distance D L is greater than the preset steering start distance Dstart, the first target steering angle θ L Set to 0. Then, the distance to the obstacle D L When the steering start distance Dstart is reached, the first target steering angle θ L That is, an obstacle on the left side of the vehicle 100 approaches, and the distance D L When the first target steering angle θ changes from a value greater than the preset steering start distance Dstart to a value less than the steering start distance Dstart, L The calculation of the steering start distance Dstart is a distance at which steering of the vehicle 100 needs to be started in order to avoid an obstacle, and is set in advance through experiments or simulations.

[0021] First, the target steering angle calculation unit 13 calculates the distance D L When the first target steering angle θ L The minimum steering angle θ Lmin (L1). The minimum steering angle θ Lminis the minimum steering angle that is set when steering to avoid an obstacle is started, and is set in advance through experiments and simulations.

[0022] Thereafter, as the vehicle 100 advances, the obstacle approaches and the distance D L When becomes smaller, the distance to the obstacle D L The smaller the first target steering angle θ L In other words, the target steering angle calculation unit 13 calculates the distance D L The first target steering angle θ is set so that the steering angle in the direction away from the obstacle increases as the vehicle 100 travels. L Calculate.

[0023] And the distance to the obstacle D L When the first target steering angle θ L Maximum steering angle θ Lmax and set the distance to the obstacle D L Even if the maximum steering angle θ Lmax (L3). Here, the minimum steering distance Dmin is the minimum distance required to avoid an obstacle by steering, and is set in advance through experiments or simulations. Also, the maximum steering angle θ Lmax is the maximum steering angle that is set to avoid an obstacle, and is set in advance through experiments or simulations.

[0024] After this, as the vehicle 100 advances, the obstacle moves away and the distance to the obstacle D L As increases, the distance to the obstacle D L The larger the first target steering angle θ L That is, the target steering angle calculation unit 13 calculates the distance D L The first target steering angle θ is set so that the steering angle in the direction away from the obstacle becomes smaller as the vehicle 100 travels. L Calculate.

[0025] And the distance to the obstacle DL When the first target steering angle θ changes from a value smaller than the steering start distance Dstart to the steering start distance Dstart, the target steering angle calculation unit 13 calculates the first target steering angle θ L The minimum steering angle θ Lmin Set to (L5).

[0026] After this, the distance to the obstacle D L While the steering start distance Dstart changes to a larger value and changes to the steering end distance Dend, the target steering angle calculation unit 13 calculates the first target steering angle from the minimum steering angle θ Lmin The steering end distance Dend is a distance at which steering to avoid an obstacle becomes unnecessary, and is set to a value greater than the steering start distance Dstart, and is set in advance by experiments or simulations.

[0027] And the distance to the obstacle D L When the first target steering angle θ becomes larger than the steering end distance Dend, the target steering angle calculation unit 13 calculates the first target steering angle θ L is set to 0 (L7). In this way, the target steering angle calculation unit 13 calculates the first target steering angle θ L Calculate.

[0028] Next, referring to FIG. 4, a second target steering angle θ, which is a target steering angle for avoiding an obstacle present on the right side of the traveling direction of the vehicle 100, is R A method for calculating the first target steering angle θ L is shown as a positive value, and in FIG. 4, the second target steering angle θ R is indicated by a negative value.

[0029] As shown in FIG. 4, the target steering angle calculation unit 13 calculates the distance D R is greater than the preset steering start distance Dstart, the first target steering angle θ R Set to 0. Then, the distance to the obstacle D R When the steering start distance Dstart is reached, the second target steering angle θ R That is, an obstacle on the right side of the vehicle 100 approaches, and the distance DR When the second target steering angle θ changes from a value greater than the preset steering start distance Dstart to a value less than the steering start distance Dstart, R Start calculation of.

[0030] First, the target steering angle calculation unit 13 calculates the distance D R When the second target steering angle θ R The minimum steering angle θ Rmin (R1). Minimum steering angle θ Rmin is the minimum steering angle θ Lmin Similarly, this is the minimum steering angle that is set when steering to avoid an obstacle is started, and is set in advance through experiments and simulations.

[0031] Thereafter, as the vehicle 100 advances, the obstacle approaches and the distance D R When becomes smaller, the distance to the obstacle D R The smaller the second target steering angle θ R Since is negative, it becomes smaller (its absolute value becomes larger) (R2). That is, the target turning angle calculation unit 13 calculates the distance D R The second target steering angle θ is set so that the steering angle in the direction away from the obstacle increases as the vehicle 100 travels. R Calculate.

[0032] And the distance to the obstacle D R When the steering distance θ becomes the minimum steering distance Dmin, the target steering angle calculation unit 13 calculates the second target steering angle θ R Maximum steering angle θ Rmax and set the distance to the obstacle D R Even if the maximum steering angle θ Rmax (R3). Here, the maximum steering angle θ Rmax is the maximum steering angle θ Lmax Similarly, this is the maximum steering angle that is set in order to avoid an obstacle, and is set in advance through experiments and simulations.

[0033] After this, as the vehicle 100 advances, the obstacle moves away and the distance to the obstacle D R As increases, the distance to the obstacle D R The larger the second target steering angle θ R Since is negative, it becomes larger (the absolute value becomes smaller) (R4). That is, the target turning angle calculation unit 13 calculates the distance D R The second target steering angle θ is set so that the steering angle in the direction away from the obstacle becomes smaller as the vehicle 100 travels. R Calculate.

[0034] And the distance to the obstacle D R When the second target steering angle θ changes from a value smaller than the steering start distance Dstart to the steering start distance Dstart, the target steering angle calculation unit 13 calculates the second target steering angle θ R The minimum steering angle θ Rmin Set to (R5).

[0035] After this, the distance to the obstacle D R While the steering start distance Dstart changes to a larger value and changes to the steering end distance Dend, the target steering angle calculation unit 13 calculates the second target steering angle θ R The minimum steering angle θ Rmin Maintain it as it is (R6).

[0036] And the distance to the obstacle D R When the steering end distance Dend becomes larger than the second target steering angle θ R is set to 0 (R7). In this way, the target steering angle calculation unit 13 calculates the second target steering angle θ R Calculate.

[0037] The target steering angle calculation unit 13 calculates the distance D L , D R becomes equal to or less than a preset vehicle stopping distance, the vehicle 100 is stopped. The vehicle stopping distance is a short distance at which it becomes difficult to avoid an obstacle by steering, is set to a value smaller than the minimum steering distance Dmin, and is set in advance by experiments or simulations.

[0038] Final turning angle calculation section 15 calculates the final turning angle by adding the first target turning angle and the second target turning angle calculated by target turning angle calculation section 13. That is, the final turning angle θ is calculated by equation (1). Final steering angle θ = 1st target steering angle θ L +2nd target steering angle θ R (1)

[0039] In addition, since the first target steering angle and the second target steering angle are steering angles in opposite directions, values ​​that cancel each other out are calculated by adding them. For example, when the first target steering angle θ L is a positive value, and the second target steering angle θ R is a negative value, so if the sum becomes positive, the final steering angle θ becomes a steering angle to the right, and if the sum becomes negative, the final steering angle θ becomes a steering angle to the left.

[0040] In addition, in the past, when the distance to an obstacle becomes equal to or smaller than a predetermined value, the steering angle is controlled so that the distance to the obstacle increases. However, in such steering control, if there are obstacles on the left and right of the vehicle, the vehicle is repeatedly steered left and right to avoid the obstacle, and the vehicle cannot move on a smooth trajectory. In response to this, the final steering angle calculation unit 15 calculates the final steering angle by adding the steering angle for avoiding the obstacle on the left side and the steering angle for avoiding the obstacle on the right side. Therefore, even if there are obstacles on the left and right of the vehicle, the vehicle can move on a smooth trajectory without repeatedly steering left and right.

[0041] Steering control unit 17 controls the steering angle of the steered wheels of vehicle 100 based on the final steering angle calculated by final steering angle calculation unit 15. Steering control unit 17 outputs the final steering angle to steering motor 5 and controls the steering angle of the steered wheels of vehicle 100 to become the final steering angle. Note that steering control unit 17 may be configured to control the steered wheels of vehicle 100 only when remotely operated by remote operation device 7.

[0042] The steering motor 5 is an actuator for steering the steered wheels of the vehicle 100, and when it acquires the final steering angle from the steering control unit 17, it steers the steered wheels of the vehicle 100 to set the final steering angle.

[0043] The remote control device 7 is a device operated by a driver outside the vehicle to remotely control the vehicle 100. For example, a forward and reverse switch is provided on the smart key of the vehicle 100, and the driver outside the vehicle operates the switch to move the vehicle 100 forward or backward and park it in a parking space.

[0044] The steering control device 1 is a controller that is configured with general-purpose electronic circuits including a microcomputer, a microprocessor, and a CPU, and peripheral devices such as a memory, and is installed with a computer program for executing steering control processing. Each function of the steering control device 1 can be implemented by one or more processing circuits. The processing circuits include, for example, programmed processing devices including electrical circuits, and also include devices such as application specific integrated circuits (ASICs) and conventional circuit components arranged to perform the functions described in the embodiments.

[0045] [Steering control processing] Next, a description will be given of the steering control process executed by the steering control device 1 according to this embodiment. Fig. 5 is a flowchart showing the processing procedure of the steering control process by the steering control device 1 according to this embodiment.

[0046] 5, in step S10, the obstacle distance acquisition unit 11 acquires the distance from the vehicle 100 to an obstacle detected by the distance detection sensor 3. At this time, when the vehicle 100 is moving forward, the obstacle distance acquisition unit 11 acquires the distance from the first left sensor LS1 and the first right sensor RS1 to the obstacles present on the left and right of the traveling direction of the vehicle 100. When the vehicle 100 is moving backward, the obstacle distance acquisition unit 11 acquires the distance from the second left sensor LS2 and the second right sensor RS2 to the obstacles present on the left and right of the traveling direction of the vehicle 100.

[0047] In step S20, target steering angle calculation unit 13 calculates a first target steering angle and a second target steering angle based on the distance to the obstacle acquired in step S10. The first target steering angle is a target steering angle for avoiding an obstacle present on the left side of vehicle 100 in the traveling direction, and the second target steering angle is a target steering angle for avoiding an obstacle present on the right side of vehicle 100 in the traveling direction.

[0048] In step S30, final turning angle calculation section 15 calculates the final turning angle by adding together the first target turning angle and the second target turning angle calculated in step S20.

[0049] Here, specific methods of calculating the target steering angle and the final steering angle will be described with reference to Figs. 6 to 9. Fig. 6 is a diagram showing a specific method of calculating the first target steering angle, and Fig. 7 is a diagram showing a specific method of calculating the second target steering angle. In Figs. 6 and 7, the parameters are set as shown in Fig. 8. That is, the steering start distance Dstart is set to 1.5 m, the steering end distance Dend is set to 2.0 m, and the minimum steering distance Dmin is set to 0.5 m. In addition, the minimum steering angle θ Lmin , θ Rmin are 10deg, -10deg, and the maximum steering angle θ Lmax , θ Rmax are set to 60 deg and -60 deg, respectively. Although the steering angle is used in the description here, when actually controlling the vehicle, the steering angle or the handle angle may be used for control.

[0050] FIG. 9 is a diagram showing specific numerical values ​​when the steering control is executed, and how the final steering angle is calculated as time passes will be described with reference to FIG. 9. First, at time t1, since no obstacle is detected, the first target steering angle θ L and the second target steering angle θ R becomes 0, so the final steering angle θ also becomes 0.

[0051] At time t2, the distance to the obstacle is D Lis detected as 1.7 m, but as shown in FIG. 6, it decreases from 2.0 m or more and is larger than the steering start distance Dstart, so the first target steering angle θ L remains 0. On the other hand, the second target steering angle θ R remains 0, so the final steering angle θ also becomes 0.

[0052] At time t3, the distance to the obstacle D L However, since the steering start distance Dstart has decreased to 1.5 m, the first target steering angle θ L is the minimum steering angle θ Lmin On the other hand, the second target steering angle θ R remains 0, so the final steering angle θ becomes 10 deg.

[0053] At time t4, the distance to the obstacle D L is reduced to 1.2 m, the steering angle in the direction away from the obstacle is calculated to be larger as the distance to the obstacle decreases. As shown in FIG. 6, the first target steering angle θ L is set to 25 deg. Meanwhile, the distance to the obstacle D R is detected as 1.7 m, but as shown in FIG. 7, it decreases from 2.0 m or more and is larger than the steering start distance Dstart, so the second target steering angle θ R remains 0. Therefore, the final steering angle θ is the first target steering angle θ L 25deg and the second target steering angle θ R is added and set to 25deg.

[0054] At time t5, the distance to the obstacle D L Since the first target steering angle θ L remains unchanged at 25 deg. Meanwhile, the distance to the obstacle D R Since the steering start distance Dstart has decreased to 1.5 m, as shown in FIG. 7, the second target steering angle θ R is the minimum steering angle θ Rmin Therefore, the final steering angle θ is set to −10 deg. L 25deg and the second target steering angle θR is added -10deg to set it to 15deg.

[0055] At time t6, the distance to the obstacle D L is reduced to 0.8 m, the steering angle in the direction away from the obstacle is calculated to be larger as the distance to the obstacle decreases, and the first target steering angle θ L is set to 45 deg. Meanwhile, the distance to the obstacle D R is reduced to 1.2 m, so that the steering angle in the direction away from the obstacle is calculated to be larger as the distance to the obstacle decreases. As shown in FIG. 7, the second target steering angle θ R is set to -25 deg. Therefore, the final steering angle θ is set to the first target steering angle θ L 45deg and the second target steering angle θ R The angle is set to 20deg by adding -25deg.

[0056] At time t7, the distance to the obstacle D L When the first target steering angle θ is reduced to 0.4 m, it becomes smaller than the minimum steering distance Dmin of 0.5 m as shown in FIG. L is the maximum steering angle θ Lmax On the other hand, the distance to the obstacle D R is reduced to 0.8 m, so that the steering angle in the direction away from the obstacle is calculated to be larger as the distance to the obstacle decreases. As shown in FIG. 7, the second target steering angle θ R is set to -45 deg. Therefore, the final steering angle θ is set to the first target steering angle θ L 60deg and the second target steering angle θ R The angle is set to 15deg by adding -45deg.

[0057] At time t8, the distance to the obstacle D L However, as shown in FIG. 6, since it is smaller than the minimum steering distance Dmin of 0.5 m, the first target steering angle θ L is the maximum steering angle θ LmaxIf the vehicle stopping distance is set to 0.2 m, the vehicle 100 may be stopped. On the other hand, the distance D R is reduced to 0.4 m, which is smaller than the minimum steering distance Dmin of 0.5 m as shown in FIG. 7. Therefore, the second target steering angle θ R is the maximum steering angle θ Lmax Therefore, the final steering angle θ is set to −60 deg. L 60deg and the second target steering angle θ R is set to 0 by adding -60deg.

[0058] At time t9, the distance to the obstacle D L increases to 0.8 m, so the steering angle in the direction away from the obstacle is calculated to be smaller as the distance to the obstacle increases. As shown in FIG. 6, the first target steering angle θ L is set to 45 deg. Meanwhile, the distance to the obstacle D R Since the second target steering angle θ R remains unchanged at -60deg. Therefore, the final steering angle θ is the first target steering angle θ L 45deg and the second target steering angle θ R is added to the angle of -60deg and set to -15deg.

[0059] At time t10, the distance to the obstacle D L increases to 1.2 m, so the steering angle in the direction away from the obstacle is calculated to be smaller as the distance to the obstacle increases. As shown in FIG. 6, the first target steering angle θ L is set to 25 deg. Meanwhile, the distance to the obstacle D R increases to 0.8 m, so the steering angle in the direction away from the obstacle is calculated to be smaller as the distance to the obstacle increases, and the second target steering angle θ R is set to -45 deg. Therefore, the final steering angle θ is set to the first target steering angle θ L 25deg and the second target steering angle θ R -45deg is added to the angle and the angle is set to -20deg.

[0060] At time t11, the distance to the obstacle D L Since the first target steering angle θ L remains unchanged at 25 deg. Meanwhile, the distance to the obstacle D R increases to 1.7 m, and changes from a value smaller than the steering start distance Dstart of 1.5 m to a value larger than the steering start distance Dstart. Therefore, as shown in FIG. 7, the second target steering angle θ R is the minimum steering angle θ Rmin The final steering angle θ is set to −10° and maintained at −10°. Therefore, the final steering angle θ is set to −10° from the first target steering angle θ L 25deg and the second target steering angle θ R is added -10deg to set it to 15deg.

[0061] At time t12, the distance to the obstacle D L increases to 1.7 m, and changes from a value smaller than the steering start distance Dstart of 1.5 m to a value larger than the steering start distance Dstart. Therefore, as shown in FIG. 6, the first target steering angle θ L is the minimum steering angle θ Lmin The distance to the obstacle D R Since the steering end distance Dend exceeds 2.0 m, it is no longer detected, and the second target steering angle θ R is set to 0. Therefore, the final steering angle θ is set to the first target steering angle θ L 10deg and the second target steering angle θ R is added to make it 10deg.

[0062] In this manner, the first target steering angle θ L and the second target steering angle θ R is calculated, and in step S30 the final steering angle θ is calculated.

[0063] In step S40, steering control unit 17 controls the steered wheels of vehicle 100 based on the final steering angle calculated in step S30. Specifically, steering control unit 17 outputs the final steering angle to steering motor 5 and controls the steered wheels of vehicle 100 to reach the final steering angle. When the steered wheels are controlled in this manner, the steering control process according to this embodiment is terminated.

[0064] [Effects of the embodiment] As described above in detail, in the steering control device 1 according to this embodiment, the first target steering angle is calculated so that the steering angle in the steering direction in which the vehicle moves away from the obstacle as the vehicle moves along becomes larger as the distance to the obstacle on the left side of the vehicle's traveling direction becomes smaller. On the other hand, the second target steering angle is calculated so that the steering angle in the steering direction in which the vehicle moves away from the obstacle as the vehicle moves along becomes larger as the distance to the obstacle on the right side of the vehicle's traveling direction becomes smaller. Then, the first target steering angle and the second target steering angle are added together to calculate a final steering angle, and the steered wheels of the vehicle are controlled based on the final steering angle. This allows the vehicle to move smoothly while avoiding the obstacle even if an obstacle is detected during the movement of the vehicle. In particular, since the final steering angle is calculated by adding together the steering angle to the right and the steering angle to the left, the vehicle can be moved on a smooth trajectory without repeatedly steering left and right even if there are obstacles on the left and right of the vehicle.

[0065] Furthermore, in the steering control device 1 according to this embodiment, calculation of the first or second target steering angle is started when the distance from the vehicle to the obstacle changes from a value larger than a preset steering start distance to a value equal to or smaller than the steering start distance. This makes it possible to start calculation of the target steering angle when it is time to start steering to avoid the obstacle.

[0066] Furthermore, in the steering control device 1 according to this embodiment, when the distance from the vehicle to the obstacle changes from a value smaller than the steering start distance to the steering start distance, the first or second target steering angle is set to a preset minimum steering angle. Then, while the distance from the vehicle to the obstacle changes from the steering start distance to the steering end distance set to a value larger than the steering start distance, the first or second target steering angle is maintained at the minimum steering angle. This prevents the target steering angle from decreasing from the steering start distance to the steering end distance, and allows the vehicle to reliably avoid the obstacle.

[0067] Furthermore, in the steering control device 1 according to this embodiment, when the distance from the vehicle to the obstacle becomes a value greater than the steering end distance, the first or second target steering angle is set to 0. This makes it possible to end steering to avoid the obstacle when the vehicle is sufficiently far away from the obstacle.

[0068] Furthermore, in the steering control device 1 according to this embodiment, when the distance from the vehicle to an obstacle becomes equal to or less than a preset vehicle stopping distance, the vehicle is stopped. This makes it possible to prevent the vehicle from coming into contact with the obstacle.

[0069] Moreover, in the steering control device 1 according to this embodiment, the distance detection sensor 3 is composed of a left sensor LS that detects the distance to an obstacle present on the left side of the vehicle's traveling direction, and a right sensor RS that detects the distance to an obstacle present on the right side of the vehicle's traveling direction. The first target steering angle is calculated based only on the distance to the obstacle detected by the left sensor LS, and the second target steering angle is calculated based only on the distance to the obstacle detected by the right sensor RS. As a result, since steering control is performed based only on the distance to the obstacle, it is not necessary to obtain the position of the obstacle, and steering control for avoiding the obstacle can be performed by simply performing a simple calculation without performing a complex calculation.

[0070] Furthermore, in the steering control device 1 according to this embodiment, the left sensor and the right sensor are configured with sonar that emits sound waves within a predetermined range and detects the distance from the vehicle to the obstacle based on the waves reflected by the obstacle. This makes it possible to execute steering control for avoiding the obstacle using an inexpensive configuration.

[0071] Furthermore, in the steering control device 1 according to this embodiment, the vehicle 100 can be remotely controlled by a remote control device 7 operated by a driver outside the vehicle, and the steered wheels of the vehicle 100 are controlled only when the vehicle is remotely controlled by the remote control device 7. This makes it possible to apply the steering control of this embodiment to control when moving a vehicle by remote control.

[0072] The above-described embodiment is merely an example of the present invention, and the present invention is not limited to the above-described embodiment, and various modifications can be made to the design and other aspects of the present invention without departing from the technical concept of the present invention. [Explanation of symbols]

[0073] 1. Steering control device 3. Distance detection sensor 5. Steering motor 7 Remote Control Device 11 Obstacle distance acquisition unit 13 Target steering angle calculation unit 15 Final steering angle calculation section 17 Steering control unit 100 vehicles LS Left Sensor RS Right Sensor LS1 First left sensor LS2 Second left sensor RS1 1st right sensor RS2 Second right sensor

Claims

1. A steering control method for controlling steering of a vehicle equipped with a distance detection sensor that detects a distance to an obstacle present around the vehicle, comprising: acquiring a distance from the vehicle to the obstacle detected by the distance detection sensor; a first target steering angle is calculated so that the shorter the distance to an obstacle present on the left side of the traveling direction of the vehicle, the larger the steering angle in a steering direction in which the vehicle moves in a direction away from the obstacle as the vehicle travels; a second target steering angle is calculated so that the shorter the distance to an obstacle present on the right side of the traveling direction of the vehicle, the larger the steering angle in the steering direction in which the vehicle moves in a direction away from the obstacle as the vehicle travels; Calculating a final steering angle by adding the first target steering angle and the second target steering angle; A steering control method comprising: controlling the steered wheels of the vehicle based on the final steering angle.

2. 2. The steering control method according to claim 1, further comprising the step of starting calculation of the first or second target steering angle when a distance from the vehicle to the obstacle changes from a value greater than a preset steering start distance to a value less than the steering start distance.

3. When the distance from the vehicle to the obstacle changes from a value smaller than the steering start distance to the steering start distance, the first or second target steering angle is set to a preset minimum steering angle, 3. The steering control method according to claim 2, wherein the first or second target steering angle is maintained at the minimum steering angle while the distance from the vehicle to the obstacle changes from the steering start distance to a steering end distance set to a value greater than the steering start distance.

4. 4. The steering control method according to claim 3, wherein the first or second target steering angle is set to 0 when the distance from the vehicle to the obstacle becomes greater than the steering end distance.

5. 5. The steering control method according to claim 1, further comprising the step of: stopping the vehicle when a distance from the vehicle to the obstacle becomes equal to or shorter than a preset vehicle stopping distance.

6. the distance detection sensor is composed of a left sensor that detects the distance to an obstacle present on the left side of the traveling direction of the vehicle, and a right sensor that detects the distance to an obstacle present on the right side of the traveling direction of the vehicle, The first target steering angle is calculated based only on a distance to the obstacle detected by the left sensor, 6. The steering control method according to claim 1, wherein the second target steering angle is calculated based only on a distance to the obstacle detected by the right sensor.

7. 7. The steering control method according to claim 6, wherein the left sensor and the right sensor are sonar sensors that emit sound waves within a predetermined range and detect the distance from the vehicle to the obstacle based on the waves reflected by the obstacle.

8. The steering control method according to any one of claims 1 to 7, characterized in that the vehicle can be remotely operated by a remote operation device operated by a driver outside the vehicle, and control of the steered wheels of the vehicle is performed only when the vehicle is remotely operated by the remote operation device.

9. A steering control device for controlling steering of a vehicle equipped with a distance detection sensor that detects a distance to an obstacle present around the vehicle, The steering control device includes: acquiring a distance from the vehicle to the obstacle detected by the distance detection sensor; a first target steering angle is calculated so that the shorter the distance to an obstacle present on the left side of the traveling direction of the vehicle, the larger the steering angle in a steering direction in which the vehicle moves in a direction away from the obstacle as the vehicle travels; a second target steering angle is calculated so that the shorter the distance to an obstacle present on the right side of the traveling direction of the vehicle, the larger the steering angle in the steering direction in which the vehicle moves in a direction away from the obstacle as the vehicle travels; Calculating a final steering angle by adding the first target steering angle and the second target steering angle; A steering control device which controls the steered wheels of the vehicle based on the final steering angle.

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