Steering control method and steering control device

Abstract

The steering control device of the present invention obtains the distance from the vehicle to the obstacle detected by the distance detection sensor, and calculates a first target steering angle in a manner such that the smaller the distance to the obstacle existing on the left side of the vehicle's traveling direction, the larger the steering angle in the steering direction in which the vehicle moves away from the obstacle as the vehicle travels; and calculates a second target steering angle in a manner such that the smaller the distance to the obstacle existing on the right side of the vehicle's traveling direction, the larger the steering angle in the steering direction in which the vehicle moves away from the obstacle as the vehicle travels; the first target steering angle and the second target steering angle are added to calculate a final steering angle, and the steering wheel of the vehicle is controlled based on the final steering angle.

Description

Technical Field

[0001] The present invention relates to a steering control method and a device for controlling the steering of a vehicle provided with a distance detection sensor for detecting the distance to an obstacle existing around the vehicle. Background Art

[0002] In the past, Patent Document 1 disclosed a vehicle with a parking assist function that can park the vehicle in a parking space by external operation. In the vehicle with a parking assist function disclosed in Patent Document 1, a vehicle user outside the vehicle moves the vehicle into the parking space by using a switch provided on a smart key.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2008-74296

[0006] Problems to be solved by the invention

[0007] However, in the above-mentioned conventional vehicle with parking assist function, if an obstacle is detected while the vehicle is moving, the vehicle has already been stopped, so there is a problem that the vehicle cannot be moved smoothly. Summary of the invention

[0008] Therefore, the present invention has been proposed in view of the above-mentioned actual situation, and an object thereof is to provide a steering control method and apparatus thereof, which can make the vehicle move smoothly while avoiding the obstacle even when an obstacle is detected during the movement of the vehicle.

[0009] In order to solve the above-mentioned problem, 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 at which the vehicle moves away from the obstacle as the vehicle moves along becomes larger as the distance to the obstacle existing on the left side of the vehicle's traveling direction becomes smaller. On the other hand, a second target steering angle is calculated so that the steering angle at which the vehicle moves away from the obstacle as the vehicle moves along becomes larger as the distance to the obstacle existing on the right side of the vehicle's traveling direction becomes smaller. Then, a final steering angle is calculated by adding the first target steering angle and the second target steering angle, and the steering wheel of the vehicle is controlled based on the final steering angle.

[0010] Effects of the Invention

[0011] According to the present invention, even when an obstacle is detected while the vehicle is moving, the vehicle can be moved smoothly while avoiding the obstacle. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1It is a block diagram showing the structure of a vehicle equipped with the steering control device according to one embodiment of the present invention.

[0013] Figure 2 It is a diagram showing the arrangement of distance detection sensors in a vehicle equipped with a steering control device according to an embodiment of the present invention.

[0014] Figure 3 It is a diagram for explaining a method of calculating a first target steering angle in the steering control device according to one embodiment of the present invention.

[0015] Figure 4 This is a diagram for explaining a method of calculating a second target steering angle in the steering control device according to the embodiment of the present invention.

[0016] Figure 5 This is a flowchart showing a processing procedure of a steering control process of the steering control device according to one embodiment of the present invention.

[0017] Figure 6 This is a diagram for explaining a specific method of calculating a first target steering angle of the steering control device according to one embodiment of the present invention.

[0018] Figure 7 It is a diagram for explaining a specific method of calculating the second target steering angle of the steering control device according to the embodiment of the present invention.

[0019] Figure 8 This 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.

[0020] Fig. 9 It is a diagram showing a specific example of the steering control performed by the steering control device according to one embodiment of the present invention. DETAILED DESCRIPTION

[0021] Hereinafter, an embodiment to which the present invention is applied will be described with reference to the accompanying drawings. In the description of the drawings, the same parts are denoted by the same reference numerals and detailed descriptions thereof will be omitted.

[0022] [Structure of a vehicle equipped with a steering control device]

[0023] Figure 1 FIG. 2 is a block diagram of the structure of a vehicle equipped with the steering control device of this embodiment. Figure 1 As shown, the vehicle 100 includes a steering control device 1, a distance detection sensor 3, a steering motor 5, and a remote control device 7. The vehicle 100 can be remotely controlled by a driver outside the vehicle through the remote control device 7.

[0024] The distance detection sensor 3 is a sensor for detecting 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 for detecting 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. In addition, the right sensor RS is a sensor for detecting 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.

[0025] like Figure 2 As shown, the first left sensor LS1 is used to detect an obstacle on the left side of the traveling direction when the vehicle 100 is moving forward, and to detect the distance D to the obstacle. L In addition, the second left sensor LS2 is used to detect an obstacle on the left side of the traveling direction when the vehicle 100 moves backward, and detect the distance D to the obstacle. L The second left sensor LS2 is provided at the right rear portion of the vehicle 100, but when the vehicle 100 moves backward, it detects an obstacle located on the left side with respect to the traveling direction of the vehicle 100 traveling backward, and thus serves as a left sensor.

[0026] Furthermore, the first right sensor RS1 is used to detect an obstacle existing on the right side of the traveling direction when the vehicle 100 is moving forward, and to detect the distance D to the obstacle. R In addition, the second right sensor RS2 is used to detect an obstacle on the right side of the traveling direction when the vehicle 100 moves backward, and detect the distance D to the obstacle. R The second right sensor RS2 is provided at the left rear portion of the vehicle 100, but when the vehicle 100 moves backward, it detects obstacles on the right side of the traveling direction of the vehicle 100 moving backward, and thus serves as a right sensor.

[0027] The left sensor LS and the right sensor RS are respectively composed of sonars, and emit sound waves to different non-overlapping ranges within a specified range on the left side of the vehicle's traveling direction and a specified 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 reflected from the obstacle. However, as long as the distance to the obstacle can be detected, it can also be a sensor other than sonar, for example, a camera or a laser rangefinder. However, the left sensor LS and the right sensor RS only need to detect the distance from the vehicle 100 to the obstacle, and may not detect the position (coordinates) of the obstacle relative to the vehicle 100. Therefore, by using a sonar that can generally only detect the distance from the vehicle 100 to the obstacle, it can be constructed more cheaply than using a camera or a laser rangefinder that can detect the distance to the obstacle and the position of the obstacle.

[0028] The steering control device 1 controls the steering wheel of the vehicle 100 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 includes an obstacle distance acquisition unit 11, a target steering angle calculation unit 13, a final steering angle calculation unit 15, and a steering control unit 17. The steering control of the steering control device 1 can be applied to the control of the steering wheel when the vehicle 100 is automatically parked in a parking space, and can also be applied to the control of the steering wheel when the vehicle 100 is remotely operated by a driver outside the vehicle through a remote control device 7 to park the vehicle 100.

[0029] The obstacle distance acquisition unit 11 acquires the distance from the vehicle 100 to the 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 to the obstacle on the left side of the traveling direction from the first left sensor LS1. L , obtain the distance D to the obstacle on the right side of the traveling direction from the first right sensor RS1 R When the vehicle 100 moves backward, the obstacle distance acquisition unit 11 acquires the distance D to the obstacle on the left side of the traveling direction (toward the rear) from the second left sensor LS2. L , obtain the distance D to the obstacle on the right side of the travel direction (towards the rear) from the second right sensor RS2 R .

[0030] The 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 by the obstacle distance acquisition unit 11. The first target steering angle is a target steering angle for avoiding an obstacle existing on the left side of the traveling direction of the vehicle 100, and becomes a steering angle to the right when the vehicle 100 moves forward, and becomes a steering angle to the left when the vehicle moves backward. In addition, the second target steering angle is a target steering angle for avoiding an obstacle existing on the right side of the traveling direction of the vehicle 100, and becomes a steering angle to the left when the vehicle 100 moves forward, and becomes a steering angle to the right when the vehicle moves backward. That is, the first target steering angle and the second target steering angle are both steering angles in the steering direction in which the vehicle moves away from the obstacle as the vehicle moves forward. Then, 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. In addition, 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).

[0031] The target steering angle calculation unit 13 calculates the first target steering angle so that the smaller the distance to the obstacle existing on the left side of the traveling direction of the vehicle 100, the larger the steering angle in the direction away from the obstacle as the vehicle 100 travels. In addition, the target steering angle calculation unit 13 calculates the second target steering angle so that the smaller the distance to the obstacle existing on the right side of the traveling direction of the vehicle 100, the larger the steering angle in the direction away from the obstacle as the vehicle 100 travels.

[0032] For example, when the vehicle 100 is moving forward and there is an obstacle on the left side of the direction of travel, the "steering angle in the direction in which the vehicle 100 moves away from the obstacle as the vehicle 100 moves forward" becomes the right steering angle. Therefore, the first target steering angle is calculated such that the steering angle to the right becomes larger as the distance to the obstacle becomes smaller. On the contrary, when the vehicle 100 is moving backward and there is an obstacle on the left side of the direction of travel (toward the rear), the "steering angle in the direction in which the vehicle 100 moves away from the obstacle as the vehicle 100 moves forward" becomes the left steering angle. Therefore, the first target steering angle is calculated such that the steering angle to the left becomes larger as the distance to the obstacle becomes smaller.

[0033] Here, refer to Figure 3 , the first target steering angle θ is a target steering angle for avoiding an obstacle on the left side of the traveling direction of the vehicle 100. L The calculation method of Figure 3 As shown, the target steering angle calculation unit 13 calculates the target steering angle at a distance D from the obstacle. L If the first target steering angle θ is greater than the preset steering start distance Dstart, L Set to 0. Then, at the distance D from the obstacle L When the steering start distance Dstart is less than the first target steering angle θ L That is, when approaching an obstacle existing on the left side of the traveling direction of the vehicle 100 and the distance D to the obstacle is L When the value changes from a value larger than the preset steering start distance Dstart to a value smaller than the steering start distance Dstart, the first target steering angle θ is started. L The steering start distance Dstart is a distance required to start steering the vehicle 100 in order to avoid an obstacle, and is set in advance through experiments and simulations.

[0034] First, the target steering angle calculation unit 13 calculates the distance D from the obstacle. L When the first target steering angle θ decreases from a value larger than the steering start distance Dstart to the steering start distance Dstart, L Set to the minimum steering angle θ Lmin(L1). Minimum steering angle θ Lmin This is the minimum steering angle set when starting to steer to avoid obstacles, and is set in advance through experiments and simulations.

[0035] Then, as the vehicle 100 moves forward, if an obstacle approaches and the distance D to the obstacle is L becomes smaller, the distance D from the obstacle L The smaller the first target steering angle θ is, the L That is, the target steering angle calculation unit 13 calculates the target steering angle based on the distance D to the obstacle. L The first target steering angle θ is calculated so that the steering angle in the direction away from the obstacle becomes larger as the vehicle 100 moves forward. L .

[0036] Moreover, when the distance to the obstacle D L When the minimum steering distance Dmin is reached, the target steering angle calculation unit 13 calculates the first target steering angle θ L Set to the maximum steering angle θ Lmax , even if the distance to the obstacle is D L The maximum steering angle θ is maintained even smaller Lmax (L3) Here, the minimum steering distance Dmin is the minimum distance required to avoid obstacles by steering, and is set in advance through experiments and simulations. In addition, the maximum steering angle θ Lmax This is the maximum steering angle set to avoid obstacles, and is set in advance through experiments and simulations.

[0037] Then, as the vehicle 100 moves away from the obstacle, when the distance D to the obstacle L When it gets bigger, the distance D from the obstacle L The larger the first target steering angle θ is, the L That is, the target steering angle calculation unit 13 calculates the target steering angle based on the distance D to the obstacle. L The first target steering angle θ is calculated so that the steering angle in the direction away from the obstacle becomes smaller as the vehicle 100 moves forward. L .

[0038] Moreover, when the distance to the obstacle D L When the target steering angle calculation unit 13 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 Set to the minimum steering angle θ Lmin (L5).

[0039] Then, at a distance D from the obstacle LDuring the period from when 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 maintains the first target steering angle at the minimum steering angle θ. Lmin (L6) The steering end distance Dend is a distance where steering is no longer required for avoiding an obstacle, and is set to a value greater than the steering start distance Dstart, and is set in advance through experiments and simulations.

[0040] Moreover, at a distance D from the obstacle L When the target steering angle calculation unit 13 changes the first target steering angle θ to a value greater than the steering end distance Dend, the target steering angle calculation unit 13 changes the first target steering angle θ to L In this way, the target steering angle calculation unit 13 calculates the first target steering angle θ L .

[0041] Next, refer to Figure 4 , the second target steering angle θ is a target steering angle for avoiding an obstacle on the right side of the traveling direction of the vehicle 100. R The calculation method of Figure 3 In the equation, the first target steering angle θ is represented by a positive value. L ,exist Figure 4 In the equation, the second target steering angle θ is represented by a negative value. R .

[0042] like Figure 4 As shown, the target steering angle calculation unit 13 calculates the target steering angle at a distance D from the obstacle. R If it is greater than the preset steering start distance Dstart, the second target steering angle θ R Set to 0. Then, at the distance D from the obstacle R When the steering start distance Dstart is less than the second target steering angle θ R That is, when approaching an obstacle existing on the right side of the traveling direction of the vehicle 100 and the distance D to the obstacle is R When the value changes from a value larger than the preset steering start distance Dstart to a value smaller than the steering start distance Dstart, the second target steering angle θ is started. R Calculation.

[0043] First, the target steering angle calculation unit 13 calculates the distance D from the obstacle. R When the second target steering angle θ decreases from a value larger than the steering start distance Dstart to the steering start distance Dstart, R Set to the minimum steering angle θ Rmin (R1). Minimum steering angle θ Rmin and the minimum steering angle θ LminSimilarly, the minimum steering angle set when starting steering to avoid an obstacle is set in advance through experiments and simulations.

[0044] Then, as the vehicle 100 moves forward, when an obstacle approaches and the distance D to the obstacle is R When it gets smaller, the distance D from the obstacle R The smaller the second target steering angle θ is, the R Because it is a negative value, it becomes smaller (the absolute value becomes larger) (R2). That is, the target steering angle calculation unit 13 uses the distance D to the obstacle as the R The second target steering angle θ is calculated so that the steering angle in the direction away from the obstacle becomes larger as the vehicle 100 moves forward. R .

[0045] Moreover, when the distance to the obstacle D R When the minimum steering distance Dmin is reached, the target steering angle calculation unit 13 calculates the second target steering angle θ R Set to the maximum steering angle θ Rmax , even if the distance to the obstacle is D R The maximum steering angle θ is maintained even when the value is further reduced. Rmax (R3). Here, the maximum steering angle θ Rmax and the maximum steering angle θ Lmax Similarly, it is a maximum steering angle set for avoiding obstacles, and is set in advance through experiments and simulations.

[0046] Then, as the vehicle 100 moves away from the obstacle, when the distance D to the obstacle R When it gets bigger, the distance D from the obstacle R The larger the second target steering angle θ is, the R Because it is a negative value, it becomes larger (the absolute value becomes smaller) (R4). That is, the target steering angle calculation unit 13 calculates the target steering angle based on the distance D to the obstacle. R The second target steering angle θ is calculated so that the steering angle in the direction away from the obstacle becomes smaller as the vehicle 100 moves forward. R .

[0047] Moreover, when the distance to the obstacle D R When the target steering angle calculation unit 13 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 Set to the minimum steering angle θ Rmin (R5).

[0048] Then, at a distance D from the obstacle RDuring the period from when the steering start distance Dstart changes to a larger value until the steering end distance Dend changes to the steering end distance Dend, the target steering angle calculation unit 13 calculates the second target steering angle θ R Maintain the minimum steering angle θ Rmin (R6).

[0049] And, at a distance D from the obstacle R When the target steering angle calculation unit 13 changes the second target steering angle θ to be greater than the steering end distance Dend, the target steering angle calculation unit 13 changes the second target steering angle θ to be greater than the steering end distance Dend. R In this way, the target steering angle calculation unit 13 calculates the second target steering angle θ R .

[0050] In addition, the target steering angle calculation unit 13 calculates the distance D from the obstacle. L , D R When the vehicle stopping distance becomes less than or equal to a preset vehicle stopping distance, the vehicle 100 stops. The vehicle stopping distance is a short distance that makes it difficult to avoid an obstacle by steering, and is set to a value smaller than the minimum steering distance Dmin and is set in advance through experiments and simulations.

[0051] The final steering angle calculation unit 15 calculates the final steering angle by adding the first target steering angle and the second target steering angle calculated by the target steering angle calculation unit 13. That is, the final steering angle θ is calculated according to the formula (1).

[0052] Final steering angle θ = first target steering angle θ L + Second target steering angle θ R (1)

[0053] 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. Figure 3 The first target steering angle θ described in L is a positive value, the second target steering angle θ R Since θ is a negative value, if the addition becomes positive, the final steering angle θ becomes a rightward steering angle, and if it becomes negative, it becomes a leftward steering angle.

[0054] In addition, conventionally, when the distance to an obstacle is less than a predetermined value, the steering angle is controlled so as to increase the distance to the obstacle. However, in such steering control, if there are obstacles on both the left and right sides of the vehicle, the vehicle is repeatedly steered to the left and right to avoid the obstacles, and thus the vehicle cannot be moved in a smooth trajectory. In contrast, the final steering angle calculation unit 15 calculates the final steering angle by adding the steering angle for avoiding the left obstacle and the steering angle for avoiding the right obstacle. Therefore, even if there are obstacles on both the left and right sides of the vehicle, the vehicle does not repeatedly steer to the left and right, and can move in a smooth trajectory.

[0055] The steering control unit 17 controls the steering angle of the steerable wheels of the vehicle 100 based on the final steering angle calculated by the final steering angle calculation unit 15. The steering control unit 17 outputs the final steering angle to the steering motor 5, and controls so that the steering angle of the steerable wheels of the vehicle 100 becomes the final steering angle. In addition, the steering control unit 17 may control the steerable wheels of the vehicle 100 only when the remote operation is performed by the remote operation device 7.

[0056] The steering motor 5 is an actuator for steering the steerable wheels of the vehicle 100 , and when receiving the final steering angle from the steering control unit 17 , the steering motor 5 steers the steerable wheels of the vehicle 100 and sets the final steering angle.

[0057] The remote control device 7 is a device for remotely controlling the vehicle 100 by the driver outside the vehicle. 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 reverse to park in a parking space.

[0058] In addition, the steering control device 1 is a controller composed of a general electronic circuit including a microcomputer, a microprocessor, 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 circuit includes, for example, a programmed processing device including a circuit, and also includes a device such as an application-specific integrated circuit (ASIC) or a conventional circuit component that is programmed to execute the functions described in the embodiment.

[0059] [Rudder control processing]

[0060] Next, a steering control process executed by the steering control device 1 of the present embodiment will be described. Figure 5 This is a flowchart showing the processing procedure of the steering control process performed by the steering control device 1 according to the present embodiment.

[0061] like Figure 5 As shown, in step S10, the obstacle distance acquisition unit 11 acquires the distance from the vehicle 100 to the obstacle detected by the distance detection sensor 3. At this time, when the vehicle 100 is moving forward, the distance to the obstacle existing on the left and right of the moving direction of the vehicle 100 is acquired from the first left sensor LS1 and the first right sensor RS1. In addition, when the vehicle 100 is moving backward, the distance to the obstacle existing on the left and right of the moving direction of the vehicle 100 is acquired from the second left sensor LS2 and the second right sensor RS2.

[0062] In step S20, the 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 existing on the left side of the traveling direction of the vehicle 100, and the second target steering angle is a target steering angle for avoiding an obstacle existing on the right side of the traveling direction of the vehicle 100.

[0063] In step S30 , the final steering angle calculation unit 15 calculates the final steering angle by adding the first target steering angle and the second target steering angle calculated in step S20 .

[0064] Here, refer to Figure 6 to Figure 9 , explaining the calculation method of the specific target steering angle and the final steering angle. Figure 6 It is a diagram showing a specific calculation method of the first target steering angle. Figure 7 is a diagram showing a specific method for calculating the second target steering angle. Figure 6 and Figure 7 In the example, the parameters are set as follows Figure 8 That is, the steering start distance Dstart is set to 1.5m, the steering end distance Dend is set to 2.0m, and the minimum steering distance Dmin is set to 0.5m. In addition, the minimum steering angle θ Lmin ,θ Rmin Set to 10 degrees and -10 degrees respectively, the maximum steering angle θ Lmax ,θ Rmax The steering angle is used in the description here, but in actual vehicle control, the steering wheel angle and the steering angle can also be used for control.

[0065] Fig. 9 This is a graph showing specific values ​​when steering control is executed. Fig. 9 , how the final steering angle is calculated over time is explained. First, at time t1, since no obstacle is detected, the first target steering angle θ L and the second target steering angle θ R is 0, so the final steering angle θ is also 0.

[0066] At time t2, the distance D to the obstacle is detected. L is 1.7m, but if Figure 6 As shown in the figure, it starts to decrease from 2.0m and is greater than the steering start distance Dstart, so the first target steering angle θ L On the other hand, due to the second target steering angle θ R It also remains at 0, so the final steering angle θ is also 0.

[0067] At time t3, the distance D to the obstacle L Reduced to 1.5m of the steering start distance Dstart, so Figure 6 As shown, the first target steering angle θ L is set to the minimum steering angle θ Lmin On the other hand, since the second target steering angle θ R Keep it at 0, so the final steering angle θ is 10deg.

[0068] At time t4, the distance D to the obstacle L Reduced to 1.2m, the calculation is that the smaller the distance to the obstacle, the greater the steering angle in the direction away from the obstacle, such as Figure 6 As shown, the first target steering angle θ L is set to 25 degrees. On the other hand, although the distance D to the obstacle R It is detected as 1.7m, but if Figure 7 As shown in the figure, it starts to decrease from 2.0m and is greater than the steering start distance Dstart, so the second target steering angle θ R remains at 0. Therefore, the final steering angle θ is set to the first target steering angle θ L The second target steering angle θ is 25 degrees R The 0 is added to get 25 degrees.

[0069] At time t5, the distance D to the obstacle L Keep 1.2m unchanged, so the first target steering angle θ L Keep 25 degrees unchanged. On the other hand, the distance D from the obstacle R Reduced to 1.5m of the steering start distance Dstart, so Figure 7 As shown, the second target steering angle θ R is set to the minimum steering angle θ Rmin Therefore, the final steering angle θ is set to the first target steering angle θ L The second target steering angle θ is 25 degrees R Add -10deg to get 15deg.

[0070] At time t6, the distance D to the obstacle L Reduced to 0.8m, so the calculation is that the smaller the distance to the obstacle, the greater the steering angle in the direction away from the obstacle, such as Figure 6 As shown, the first target steering angle θ L is set to 45 degrees. On the other hand, due to the distance D from the obstacle RReduced to 1.2m, the calculation is that the smaller the distance to the obstacle, the greater the steering angle in the direction away from the obstacle, such as Figure 7 As shown, the second target steering angle θ R Therefore, the final steering angle θ is set to the first target steering angle θ L The second target steering angle θ is 45 degrees R Add -25deg to get 20deg.

[0071] At time t7, when the distance to the obstacle is D L When it is reduced to 0.4m, Figure 6 As shown in FIG. 1 , it becomes smaller than the minimum steering distance Dmin of 0.5 m. Therefore, the first target steering angle θ L is set to the maximum steering angle θ Lmax On the other hand, due to the distance D from the obstacle R Reduced to 0.8m, so the calculation is that the smaller the distance to the obstacle, the greater the steering angle in the direction away from the obstacle, such as Figure 7 As shown, the second target steering angle θ R Therefore, the final steering angle θ is set to the first target steering angle θ L The 60deg and the second target steering angle θ R Add -45deg to get 15deg.

[0072] At time t8, although the distance to the obstacle D L Reduced to 0.2m, but if Figure 6 As shown in the figure, since it is less than 0.5m of the minimum steering distance Dmin, the first target steering angle θ L Maintain the maximum steering angle θ Lmax The 60 degrees of the obstacle remain unchanged. In addition, when the vehicle stopping distance is set to 0.2 m, the vehicle 100 can also be stopped. On the other hand, due to the distance D R Reduced to 0.4m, such as Figure 7 As shown, it is less than 0.5m of the minimum steering distance Dmin, so the second target steering angle θ R is set to the maximum steering angle θ Lmax Therefore, the final steering angle θ is set to the first target steering angle θ L The 60deg and the second target steering angle θ R Add -60deg to get 0.

[0073] At time t9, due to the distance D to the obstacle LIncreased to 0.8m, so the calculation is that the greater the distance to the obstacle, the smaller the steering angle in the direction away from the obstacle, such as Figure 6 As shown, the first target steering angle θ L is set to 45 degrees. On the other hand, due to the distance D from the obstacle R Keep 0.4m unchanged, so if Figure 7 As shown, the second target steering angle θ R Keep -60 degrees unchanged. Therefore, the final steering angle θ is set to the first target steering angle θ L The second target steering angle θ is 45 degrees R Add -60deg to get -15deg.

[0074] At time t10, due to the distance D to the obstacle L Increased to 1.2m, so the calculation is that the greater the distance to the obstacle, the smaller the steering angle in the direction away from the obstacle, such as Figure 6 As shown, the first target steering angle θ L is set to 25 degrees. On the other hand, due to the distance D from the obstacle R Increased to 0.8m, so the calculation is that the greater the distance to the obstacle, the smaller the steering angle in the direction away from the obstacle, such as Figure 7 As shown, the second target steering angle θ R is set to -45 degrees. Therefore, the final steering angle θ is set to the first target steering angle θ L The second target steering angle θ is 25 degrees R Add -45deg to get -20deg.

[0075] At time t11, due to the distance D to the obstacle L Keep 1.2m unchanged, so if Figure 6 As shown, the first target steering angle θ L Keep 25 degrees unchanged. On the other hand, the distance D from the obstacle R Increased to 1.7m, from a value of 1.5m less than the rudder start distance Dstart to a value greater than the rudder start distance Dstart. Figure 7 As shown, the second target steering angle θ R is set to the minimum steering angle θ Rmin Therefore, the final steering angle θ is set to the first target steering angle θ L The second target steering angle θ is 25 degrees R Add -10deg to get 15deg.

[0076] At time t12, the distance D to the obstacleL Increased to 1.7m, from a value of 1.5m less than the rudder start distance Dstart to a value greater than the rudder start distance Dstart. Figure 6 As shown, the first target steering angle θ L is set to the minimum steering angle θ Lmin On the other hand, due to the distance D from the obstacle R The second target steering angle θ exceeds the steering end distance Dend by 2.0m, so it will not be detected. R is set to 0. Therefore, the final steering angle θ is set to the first target steering angle θ L The second target steering angle θ is 10 degrees R The 0deg is added to get 10deg.

[0077] Thus, in step S20, the first target steering angle θ is calculated. L and the second target steering angle θ R , and the final steering angle θ is calculated in step S30.

[0078] In step S40, the steering control unit 17 controls the steering wheels of the vehicle 100 based on the final steering angle calculated in step S30. Specifically, the steering control unit 17 outputs the final steering angle to the steering motor 5 and controls so that the steering angle of the vehicle 100 becomes the final steering angle. When the steering wheels are controlled in this way, the steering control process of this embodiment ends.

[0079] [Effects of Embodiment]

[0080] As described in detail above, in the steering control device 1 of the present embodiment, the first target steering angle is calculated so that the steering angle at which the vehicle moves away from the obstacle as the vehicle moves forward becomes larger as the distance to the obstacle existing 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 at which the vehicle moves away from the obstacle as the vehicle moves forward becomes larger as the distance to the obstacle existing 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 to calculate the final steering angle, and the steering wheel of the vehicle is controlled based on the final steering angle. Thus, even if an obstacle is detected while the vehicle is moving, the vehicle can be moved smoothly while avoiding the obstacle. In particular, since the final steering angle is calculated by adding the steering angle to the right and the steering angle to the left, even if there are obstacles on both the left and right sides of the vehicle, the vehicle does not repeatedly steer to the left and right, and can be moved in a smooth trajectory.

[0081] In addition, in the steering control device 1 of the present embodiment, when the distance from the vehicle to the obstacle changes from a value larger than a preset steering start distance to a value smaller than the steering start distance, calculation of the first or second target steering angle is started. Thus, calculation of the target steering angle can be started when the time to start steering to avoid the obstacle is reached.

[0082] Furthermore, in the steering control device 1 of the present 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. Furthermore, during the period when 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. Thus, during the period from the steering start distance to the steering end distance, the target steering angle does not decrease, and the vehicle can be reliably caused to avoid the obstacle.

[0083] In the steering control device 1 of this embodiment, when the distance from the vehicle to the obstacle becomes larger than the steering end distance, the first or second target steering angle is set to 0. Thus, steering for avoiding the obstacle can be ended when the vehicle is sufficiently away from the obstacle.

[0084] Furthermore, in the steering control device 1 of the present embodiment, the vehicle is stopped when the distance from the vehicle to the obstacle is equal to or less than a preset vehicle stopping distance. In this way, the vehicle can be prevented from contacting the obstacle.

[0085] In addition, in the steering control device 1 of the present embodiment, the distance detection sensor 3 is composed of a left sensor LS for detecting the distance to an obstacle existing on the left side of the vehicle's traveling direction, and a right sensor RS for detecting the distance to an obstacle existing on the right side of the vehicle's traveling direction. Then, 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. Thus, since the steering control is performed based only on the distance to the obstacle, it is not necessary to calculate the position of the obstacle, etc., and the steering control for avoiding the obstacle can be performed only by simple calculation without performing complicated calculations.

[0086] Furthermore, in the steering control device 1 of this embodiment, the left sensor and the right sensor are composed of sonars that emit sound waves within a predetermined range and detect the distance from the vehicle to the obstacle based on the reflected waves reflected by the obstacle. This makes it possible to perform steering control for avoiding obstacles using an inexpensive configuration.

[0087] In addition, in the steering control device 1 of the present embodiment, the vehicle 100 can be remotely operated by the remote operation device 7 operated by the driver outside the vehicle, and the steering wheel of the vehicle 100 is controlled only when the remote operation is performed by the remote operation device 7. Therefore, the steering control of the present embodiment can be applied to the control when the vehicle is moved during remote operation.

[0088] The above embodiment is an example of the present invention. Therefore, the present invention is not limited to the above embodiment, and various changes can be made according to the design etc. as long as they do not deviate from the technical concept of the present invention, even if it is a mode other than the embodiment.

[0089] Explanation of symbols

[0090] 1: Steering control device

[0091] 3: Distance detection sensor

[0092] 5: Steering motor

[0093] 7: Remote control device

[0094] 11: Obstacle distance acquisition unit

[0095] 13: Target steering angle calculation unit

[0096] 15: Final steering angle calculation unit

[0097] 17: Steering control unit

[0098] 100: Vehicles

[0099] LS: Left sensor

[0100] RS: Right sensor

[0101] LS1: First left sensor

[0102] LS2: Second left sensor

[0103] RS1: First right sensor

[0104] RS2: Second right sensor

Claims

1. A steering control method for controlling the steering of a vehicle, wherein the vehicle is provided with a distance detection sensor for detecting the distance to an obstacle existing around the vehicle, characterized in that: acquiring the distance from the vehicle to the obstacle detected by the distance detection sensor, The first target steering angle is calculated so that the smaller the distance to the obstacle existing on the left side of the vehicle in the traveling direction, the larger the steering angle in the steering direction in which the vehicle moves away from the obstacle as the vehicle travels. The second target steering angle is calculated so that the smaller the distance to an obstacle existing on the right side of the vehicle in the traveling direction, the larger the steering angle in the steering direction in which the vehicle moves away from the obstacle as the vehicle travels. The first target steering angle and the second target steering angle are added to calculate a final steering angle. A steerable wheel of the vehicle is controlled based on the final steer angle.

2. The steering control method according to claim 1, characterized in that: When the distance from the vehicle to the obstacle changes from a value greater than a preset turning start distance to a value less than the turning start distance, calculation of the first target turning angle or the second target turning angle is started.

3. The steering control method according to claim 2, characterized in that: When the distance from the vehicle to the obstacle changes from a value smaller than the steering start distance to the steering start distance, setting the first target steering angle or the second target steering angle to a preset minimum steering angle, The first target steering angle or the 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 larger than the steering start distance.

4. The steering control method according to claim 3, characterized in that: When the distance from the vehicle to the obstacle becomes a value greater than the steering end distance, the first target steering angle or the second target steering angle is set to zero.

5. The steering control method according to any one of claims 1 to 4, characterized in that: When the distance from the vehicle to the obstacle becomes equal to or smaller than a preset vehicle stopping distance, the vehicle is stopped.

6. The steering control method according to any one of claims 1 to 4, characterized in that: The distance detection sensor is composed of a left sensor for detecting the distance to an obstacle existing on the left side of the traveling direction of the vehicle, and a right sensor for detecting the distance to an obstacle existing on the right side of the traveling direction of the vehicle. calculating the first target steering angle based only on the distance to the obstacle detected by the left sensor, The second target steering angle is calculated based only on the distance to the obstacle detected by the right sensor.

7. The steering control method according to claim 6, characterized in that: The left sensor and the right sensor are sonars that emit sound waves into a predetermined range and detect the distance from the vehicle to the obstacle based on the reflected waves reflected by the obstacle.

8. The steering control method according to any one of claims 1 to 4, characterized in that: The vehicle can be remotely operated by a remote operation device operated by a driver outside the vehicle, and the steering wheel of the vehicle is controlled only when the remote operation is performed by the remote operation device.

9. A steering control device for controlling steering of a vehicle, wherein the vehicle is provided with a distance detection sensor for detecting a distance to an obstacle existing around the vehicle, wherein: The steering control device performs the following processing: acquiring the distance from the vehicle to the obstacle detected by the distance detection sensor, The first target steering angle is calculated so that the smaller the distance to the obstacle existing on the left side of the vehicle in the traveling direction, the larger the steering angle in the steering direction in which the vehicle moves away from the obstacle as the vehicle travels. The second target steering angle is calculated so that the smaller the distance to an obstacle existing on the right side of the vehicle in the traveling direction, the larger the steering angle in the steering direction in which the vehicle moves away from the obstacle as the vehicle travels. The first target steering angle and the second target steering angle are added to calculate a final steering angle. A steerable wheel of the vehicle is controlled based on the final steer angle.

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