JP5077547B2 - Parking assistance device for vehicles - Google Patents

Description

  The present invention relates to a vehicle parking assistance device that supports a driving operation for parking by controlling a turning angle of a wheel so that the vehicle turns along a target locus from an initial position.

2. Description of the Related Art Conventionally, a turning control technique for turning a vehicle in a narrow space by independently turning front, rear, left and right wheels is known. For example, in the turning control technique proposed in Patent Document 1, information on the surroundings of the vehicle is acquired, an optimal turning center is calculated so as to avoid surrounding obstacles, and the vehicle turns at the calculated turning center. Control the turning angle of the front, rear, left and right wheels. Parking driving operation is supported by automatic driving using such turning control technology.
JP2007-30808

Such turning control technology is used when a vehicle is placed in a narrow space such as a parking lot, but it is necessary to change the turning center from moment to moment as the vehicle moves, and the calculation for calculating the turning center sequentially is complicated. It becomes. Therefore, the calculation load of the microcomputer is large and high specifications are required. In addition, the development man-hours will increase. As a result, in order to mount such a technology on a vehicle, a large cost increase is caused.
Further, in the turning control technique proposed in Patent Document 1, when a vehicle is turned and put into a garage, it cannot be parked in a narrow space that is a parking limit determined by the vehicle body size.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a vehicle parking assistance apparatus that can turn a vehicle in a narrow space by simple control.

  In order to achieve the above object, the features of the present invention include a steering actuator that independently adjusts the steering angle of at least the front and rear wheels, a steering angle detection means that detects the steering angle of each wheel, Wheel rolling distance detecting means for detecting the rolling distance of each wheel; target turning angle setting means for setting a target turning angle of each wheel corresponding to the rolling distance of each wheel from the initial position of the vehicle; Steering control means for driving and controlling the steering actuator so that the detected turning angle becomes the target turning angle, and parked so that the vehicle turns along the target locus from the initial position. In the vehicle parking assistance device for assisting driving operation, the target turning angle setting means includes a vehicle traveling direction side corner portion of the vehicle opposite to the turning direction passing through the traveling direction side corner portion at the initial position in the vehicle width direction. Moves along a straight line extending to and turns Corresponding to the rolling distance of each wheel so that the opposite corner of the vehicle on the opposite side of the vehicle moves along a straight line extending in the vehicle longitudinal direction through the corner in the opposite direction at the initial position. The purpose is to set the target turning angle of each wheel.

  In the present invention configured as described above, the target turning angle setting means sets the target turning angle of each wheel corresponding to the rolling distance of each wheel from the initial position of the vehicle. Therefore, the target turning angle of each wheel is uniquely set from the rolling distance of that wheel. The rolling distance of each wheel is detected by the wheel rolling distance detecting means, and the turning angle of each wheel is detected by the turning angle detecting means. Then, the turning control means controls the turning angle of each wheel to the target turning angle by driving and controlling the turning actuator using the detection results of these detecting means. As a result, the vehicle can be turned from the initial position along the target locus.

  In this case, the target turning angle setting means moves along a straight line in which the traveling direction side corner of the vehicle opposite to the turning direction passes through the traveling direction side corner at the initial position and extends in the vehicle width direction. Of each wheel corresponding to the rolling distance of each wheel so that the counter-traveling-direction side corner of the vehicle opposite to the direction moves along a straight line extending in the vehicle front-rear direction through the counter-traveling-direction side corner at the initial position. Set the target turning angle. That is, the target turning angle setting means sets the movement trajectory of the two corners at the front and rear of the vehicle in a straight line, and one of the two corners is a straight line extending in the vehicle width direction from the initial position of the vehicle. The other one point is set to move along a straight line extending in the vehicle front-rear direction from the initial position of the vehicle. The former corner is a corner in the traveling direction of the vehicle opposite to the turning direction, and the latter corner is a corner in the opposite direction of the vehicle opposite to the turning direction. Further, the advancing direction side is a direction side in which the vehicle travels, and is the vehicle head side when turning while moving forward, and the vehicle rear side when turning while moving backward. Further, the counter-traveling direction side is the opposite side to the direction in which the vehicle travels. When turning while moving forward, it is the rear side of the vehicle, and when turning while moving backward, it is the front side of the vehicle.

  For example, when turning forward in the left direction, the traveling direction side corner of the vehicle on the opposite side to the turning direction is the right end of the vehicle head, and the opposite side direction corner of the vehicle on the opposite side to the turning direction is the rear side of the vehicle. It becomes the right end. In addition, when turning forward in the right direction, the traveling direction side corner of the vehicle on the opposite side to the turning direction is the left end of the vehicle head, and the opposite side corner of the vehicle on the opposite side to the turning direction is the rear portion of the vehicle. It becomes the left end.

  In addition, when turning backward in the left direction, the traveling direction side corner of the vehicle opposite to the turning direction is the rear right corner of the vehicle, and the counter traveling direction side corner of the vehicle opposite to the turning direction is the vehicle front portion. It becomes the right end. In addition, when turning backward in the right direction, the traveling direction side corner of the vehicle opposite to the turning direction is the left rear end of the vehicle, and the counter traveling direction side corner of the vehicle opposite to the turning direction is the vehicle front portion. It becomes the left end.

  Therefore, of the front and rear corners on the right or left side of the vehicle, the corners in the traveling direction move linearly from the initial position to the vehicle width direction, and the opposite corners straight from the initial position to the vehicle longitudinal direction. The direction of the vehicle is controlled to move. Thus, the vehicle can turn without protruding the straight line extending in the vehicle width direction and the straight line extending in the vehicle front-rear direction at the initial position outward in the turning radial direction.

  For this reason, according to this invention, a vehicle can be put in a narrow parking lot, without setting the turning center of a vehicle sequentially. For example, when the width of the parking lot is narrow and the passage for entering the parking lot is perpendicular to the parking direction and is narrow, the approach path to the parking lot becomes a narrow L-shaped course. Even in such a case, according to the present invention, the vehicle is started to turn with the position where the corner of the vehicle is brought close to the corner of the L-shaped course as the initial position. The vehicle can be turned and parked on the character course. Therefore, garage entry into a narrow parking lot becomes very easy.

  In addition, by setting the target turning angle uniquely with respect to the rolling distance of the wheels, the vehicle always turns from the initial position with a constant target trajectory, so there is no need to sequentially set the turning center of the vehicle. Not complicated. Therefore, high processing capability is not required for an arithmetic processing circuit such as a microcomputer. Also, the development man-hours can be reduced.

  In addition, since the vehicle can turn without extending the straight line extending in the vehicle width direction and the straight line extending in the vehicle front-rear direction at the initial position of the vehicle, the driver should mainly pay attention to the inside of the vehicle turning direction. It is possible to omit or simplify the periphery monitoring sensor. As a result, parking assistance can be implemented at low cost.

  The turning actuator independently adjusts at least the turning angles of the front and rear wheels. Preferably, the turning angles of the front and rear wheels and the left and right wheels are preferably adjusted independently. In this case, the turning angle detection means detects the turning angles of the front, rear, left and right wheels, the wheel rolling distance detection means detects the turning distances of the front, rear, left and right wheels, and the target turning angle setting means The target turning angle of each wheel corresponding to the rolling distance of the front, rear, left and right wheels from the initial position of the vehicle is set. Further, in a configuration in which the steering actuator independently adjusts the steering angles of the front and rear wheels, that is, a configuration in which the left and right wheels are not independently steered, the steering angle detection means at least turns the front and rear wheels. The steering angle is detected, the wheel rolling distance detection means detects the rolling distance of the front, rear, left and right wheels, and the target turning angle setting means corresponds to the rolling distance of the front, rear, left and right wheels from the initial position of the vehicle. Set the target turning angle of at least the front and rear wheels.

  Another feature of the present invention is that the target turning angle setting means assumes that the vehicle is rectangular in plan view, and the first vertex of the rectangle that is the corner in the traveling direction of the vehicle on the opposite side to the turning direction is the initial one. It moves along a straight line extending in the vehicle width direction through the first apex at the position, and the second apex of the rectangle that is the opposite corner of the vehicle in the opposite direction to the turning direction is the second apex at the initial position. The target turning angle of each wheel corresponding to the rolling distance of each wheel is set so as to move along a straight line extending in the vehicle longitudinal direction.

  In the present invention, the vehicle is assumed to be rectangular in plan view, the two corners of the vehicle are regarded as the vertices of the rectangle, and the target rotation of the wheel is made so that the movement trajectory of the two corners is a straight line and orthogonal. The rudder angle is set. Therefore, it becomes easy to set the target turning angle of each wheel corresponding to the rolling distance of the wheel.

  Further, another feature of the present invention is provided with a turning instruction means for instructing the driver to start support for the parking driving operation, and the steering control means is configured to start support for the parking driving operation by the turning instruction means. When instructed, drive control of the steering actuator is started so that the turning angle of each wheel becomes the target turning angle set by the target turning angle setting means.

  In this invention, when the driver uses the turning instruction means to instruct the start of parking driving operation support, the turning control means controls the turning actuator to set the turning angle of each wheel to the target turning angle. . Therefore, the position of the vehicle when the driver gives an instruction to start assisting the parking driving operation becomes the initial position, and the vehicle is controlled to turn along the target locus from the initial position. According to this, the turning angle of each wheel is automatically controlled to the target turning angle corresponding to the rolling distance in accordance with the driver's instruction, and the vehicle can be turned with a constant trajectory.

  For example, when a vehicle enters a parking lot along an L-shaped narrow approach course, the vehicle is stopped parallel to the course by bringing the front corner or rear corner of the vehicle close to the corner of the L-shaped course. In this state, the turning instruction means instructs the start of assistance for the driving operation for parking, whereby the turning angle of the wheel is set to the target turning angle corresponding to the rolling distance from the stop position. For this reason, the driver can turn the vehicle along a narrow L-shaped course without operating the steering wheel.

  Another feature of the present invention includes wheel position movement control means for moving the ground contact center position of the wheel in the vehicle width direction with respect to the vehicle body in accordance with the turning angle of the wheel, and the target turning angle setting means includes: The target turning angle is set in consideration of the movement in the vehicle width direction of the ground contact center position of the wheel.

  The narrower L-shaped course can be turned as the vehicle is moved all the way to the one side of the passage, but the wheel steered at the start of turning may protrude outward from the vehicle body and hit an obstacle such as a wall at the end of the passage. In such a case, it is necessary to bring the vehicle inward from the end of the passage as much as the wheel protrudes, making it impossible to make a turn with the maximum use of the passage width.

  Therefore, in the present invention, the wheel position moving means moves the ground contact center position of the wheel inward in the vehicle width direction with respect to the vehicle body according to the turning angle of the wheel, so that the wheel does not protrude from the vehicle body. can do. For example, the greater the turning angle of the wheel, that is, the farther the wheel is from the neutral position (the position that advances in the straight direction), the more the wheel ground contact center position is moved inward in the vehicle width direction.

  At this time, the target turning angle setting means sets the target turning angle in consideration of the movement in the vehicle width direction of the ground contact center position of the wheel. The other corner can be moved in the vehicle longitudinal direction. As a result, the vehicle can enter and park on an L-shaped course that is narrow to the limit of the vehicle body size.

  Another feature of the present invention is that the wheel position movement control means is configured so that the outer end in the vehicle width direction of the wheel is positioned on the same vertical plane extending in the vehicle front-rear direction regardless of the change in the turning angle. The wheel center contact position is moved in the vehicle width direction with respect to the vehicle body in accordance with the turning angle.

  According to the present invention, the amount of movement of the ground contact center position of the wheel is set so that the outer end in the vehicle width direction of the wheel is positioned on the same vertical plane extending in the vehicle front-rear direction regardless of the change in the turning angle. Accordingly, the wheels can be positioned as far as possible in the vehicle width direction as long as the wheels do not protrude outside the vehicle body. Therefore, stable turning traveling can be maintained.

  Another feature of the present invention is that the wheel position movement control means includes a movement actuator that moves the grounding center position of the wheel in the vehicle width direction with respect to the vehicle body, and a movement amount that detects a movement amount of the grounding center position of the wheel. There is provided detection means and movement control means for driving and controlling the movement actuator so that the detected movement amount becomes a target movement amount set in accordance with the turning angle of the wheel.

  In the present invention, the movement control means detects the movement amount of the ground contact center position of the wheel, and the movement control means sets the detected movement amount to a target movement amount set according to the turning angle of the wheel. Drive and control the moving actuator. Accordingly, the ground contact center position of the wheel can be accurately moved to the target position.

  Another feature of the present invention is that it is applied to a vehicle provided with four-wheel independent drive means for independently rotating the front, rear, left and right wheels.

  In this invention, since the wheel driving means gives independent rotational driving force to the front, rear, left and right wheels, the vehicle can be turned well with the wheels kept at a large steering angle.

  Another feature of the present invention is that when the target turning angle of the wheel exceeds the steerable range by the turning actuator, the turning angle obtained by reversing the target turning angle by 180 ° to the left and right is set as the target turning angle. And a reversing control means for outputting a reversing command so as to reverse the rotational driving direction of the wheel with respect to the four-wheel independent driving means.

  According to this invention, even if the target turning angle of the wheel exceeds the steerable range of the turning actuator, the wheel can be rolled in the target travel direction.

  Hereinafter, a vehicle parking assistance apparatus according to an embodiment of the present invention will be described with reference to the drawings. The vehicle parking assistance device of the present invention is configured to also serve as a steering device, and can be said to have a function of assisting a parking driving operation in the steering device. FIG. 1 is a schematic configuration diagram illustrating the vehicle parking assistance apparatus according to the embodiment together with a four-wheel independent drive unit.

This vehicle is a four-wheel independent-steering vehicle, and includes a left front wheel W _FL , a right front wheel W _FR , a left rear wheel W _RL , and a right rear wheel W _RR that can be steered independently. As shown in FIG. 4, the wheel for turning the left front wheel W _FL , the right front wheel W _FR , the left rear wheel W _RL , and the right rear wheel W _RR (hereinafter collectively referred to as the wheel W if not specified). A rudder mechanism 10 is provided.

  The steering mechanism 10 provided on each wheel W includes a knuckle 11 and a steering motor 12. The knuckle 11 is connected to the inside of the wheel W and rotatably supports the wheel W. The knuckle 11 extends upward from the inner side of the wheel W, and is bent in the vehicle width direction outside in the middle of the knuckle 11 to be connected to the steering motor 12. The steering motor 12 is fixed to the vehicle body via a suspension device (not shown), and the rotation output shaft thereof is arranged on a vertical line passing through the ground contact center point of the tire of the wheel W. The steered motor 12 includes a reduction gear inside, and transmits this reduced rotational torque to the knuckle 11. Accordingly, the knuckle 11 rotates around the vertical line passing through the ground contact center point of the tire of the wheel W by the rotation of the steering motor 12 to steer the wheel W.

  For this reason, the steering mechanism 10 is set so that the steering angle can be increased and the wheels W can be steered up to 90 ° in the left-right direction. That is, the position at which the wheel W is oriented parallel to the longitudinal direction of the vehicle body is defined as a neutral position, and the turning angle, which is the direction of the wheel W with respect to the neutral position as a reference, can be changed to 90 ° to the right and left, respectively. Is set.

Incidentally, the steering motor 12 provided in each turning mechanism 10 to be driven and controlled independently, hereinafter steering motor 12a of the motor for steering the left front wheel W _FL, a right front wheel W _FR the steering motor 12b a motor for steering, the steering motor 12c to the motor for steering the left rear wheel W _RL, a motor for steering the right rear wheel W _RR and steering motor 12d is referred to. The steering motor 12 corresponds to the steering actuator in the present invention.

  As shown in FIG. 1, each of the steering motors 12a, 12b, 12c, and 12d is connected to motor drive circuits 13a, 13b, 13c, and 13d, respectively. The motor drive circuits 13a, 13b, 13c, and 13d (hereinafter simply referred to as the motor drive circuit 13 when collectively referred to) include a bridge circuit or the like (for example, an inverter circuit) configured by a plurality of switching elements. The steering motors 12a, 12b, 12c, and 12d are freely reversible at a voltage corresponding to a control signal (for example, a PWM control signal) output from the steering control unit 50 (hereinafter referred to as the steering ECU 50). To rotate. Therefore, the turning ECU 50 and the motor drive circuit 13 constitute the turning control means in the present invention.

Inside the wheels W _FL , W _FR , W _RL , W _RR , there are drive motors 14 a, 14 b, 14 c, 14 d (hereinafter simply referred to as the drive motor 14 when collectively referred to) as knuckle 11. Fixed and built-in. The drive motor 14 is a so-called in-wheel motor, and applies rotational torque generated by energization to the wheels W via a speed reducer such as a planetary gear.

  The drive motors 14a, 14b, 14c, and 14d are connected to motor drive circuits 15a, 15b, 15c, and 15d, respectively. The motor drive circuits 15a, 15b, 15c, and 15d (hereinafter simply referred to as the motor drive circuit 15 when collectively referred to) include a bridge circuit or the like (for example, an inverter circuit) configured by a plurality of switching elements. The drive motors 14a, 14b, 14c, and 14d are freely reversible at a voltage corresponding to a control signal (for example, PWM control signal) output from the wheel drive control unit 100 (hereinafter referred to as the wheel drive ECU 100). Rotation drive.

  Therefore, the vehicle on which the vehicle parking assistance device of the present embodiment is mounted has a wheel drive actuator (for example, the drive motor 14) that rotationally drives each wheel W and a wheel that independently drives and controls each wheel drive actuator. Four-wheel independent drive means having drive control means (for example, motor drive circuit 15 and wheel drive ECU 100) is provided.

  The steering ECU 50 is configured with a microcomputer including a CPU, ROM, RAM, and the like as a main part. Wheel steering angle sensors 21a, 21b, 21c, 21d and wheel speed sensors 22a, 22b, 22c, 22d, a steering wheel angle sensor 23, a steering torque sensor 24, an operation input unit 25, and a shift position sensor 26 are connected. Further, the steering ECU 50 has motor drive circuits 13a, 13b, 13c, and 13d connected to an output interface. The steering ECU 50 is provided so as to be able to exchange data with the wheel driving ECU 100.

Wheel steering angle sensors 21a, 21b, 21c, and 21d (hereinafter simply referred to as wheel steering angle sensor 21 when collectively referred to) detect the steering angles of the wheels W _FL , W _FR , W _RL , W _RR. Is. For example, a rotation angle sensor (not shown) that is incorporated in each steering motor 12 and detects a motor rotation angle (rotation position) can be used. That is, since the rotation angle of the steering motor 12 and the steering angle of the wheel W correspond one-to-one, the steering angle is detected from the motor rotation angle detected by the rotation angle sensor used for motor rotation control. It is. Each wheel rudder angle sensor 21a, 21b, 21c, 21d has a steered angle when the wheels W _FL , W _FR , W _RL , W _RR are facing the neutral position as 0 °, and the wheel W _FL , Signals representing the steering angles δ _FL , δ _FR , δ _RL , and δ _RR of W _FR , W _RL , and W _RR are output to the steering ECU 50. In the present embodiment, the leftward turning angle is represented by a positive value, and the rightward turning angle is represented by a negative value. The wheel steering angle sensors 21a, 21b, 21c, and 21d correspond to the steering angle detection means in the present invention.

The wheel speed sensors 22a, 22b, 22c, and 22d detect the rotational speeds of the wheels W _FL , W _FR , W _RL , and W _RR and determine the rotational speeds of the wheel speeds ω _FL , ω _FR , ω _RL , and ω _RR . The signal to represent is output to steering ECU50. The rolling distance of the wheel W is obtained from the outer diameter of the wheel W (stored in the steering ECU 50) and the wheel speed. Therefore, in this embodiment, the wheel rolling distance detection means is constituted by the wheel speed detection by the wheel speed sensor 22 and the steering ECU 50 that calculates the wheel rolling distance using the wheel speed. The wheel speed signals ω _FL , ω _FR , ω _RL , and ω _RR detected by the wheel speed sensors 22 a, 22 b, 22 c, and 22 d are also output to the wheel drive ECU 100. The wheel rolling distance can also be detected using a rotation angle sensor (not shown) that detects the rotation angle of the drive motor 14. That is, since the rotation angle of the drive motor 14 and the rotation angle of the wheel W correspond one-to-one, the rotation angle of the wheel W is determined from the motor rotation angle detected by a rotation angle sensor (not shown) used for motor rotation control. It is possible to adopt a configuration that detects and calculates the wheel rolling distance from the rotation angle and the outer diameter of the wheel W.

  The steering wheel steering angle sensor 23 detects a rotation angle with respect to the neutral position of the steering wheel 40 as a steering wheel steering angle, and outputs a signal representing the steering wheel steering angle θh to the steering ECU 50.

  The steering torque sensor 24 detects torque input to the steering shaft 41 when the driver rotates the steering handle 40 as steering torque, and outputs a signal representing the steering torque Th to the steering ECU 50.

  The operation input unit 25 is an operation unit provided near the driver's seat and input by the driver. The operation input unit 25 is a mode selection switch 25a for selecting a turning parking support mode, a start switch 25b for instructing the start of turning parking support control, and a turning parking. A turning direction selection switch 25c for selecting a turning direction in the assist control is provided. The operation input unit 25 may be provided exclusively, but an information terminal device can also be used. For example, a mode selection screen for selecting a turning parking support mode, a start screen for instructing the start of turning parking support control, and a turning direction selection screen for selecting a turning direction in the turning parking support control using the touch panel display of the navigation device May be displayed so that a touch operation can be performed on the screen for each display screen. Note that the start switch 25b of the present embodiment corresponds to the turning instruction means in the present invention.

  The shift position sensor 26 detects the position of a shift lever (not shown) and outputs a signal representing the shift position to the steering ECU 50. The shift position signal detected by the shift position sensor 26 is also output to the wheel driving ECU 100.

  The wheel driving ECU 100 is configured with a microcomputer including a CPU, a ROM, a RAM, and the like as a main part. The wheel speed sensors 22a, 22b, 22c, and 22d, an accelerator pedal sensor 27, and a brake pedal sensor 28 are input interfaces. And the shift position sensor 26 are connected. In addition, the wheel driving ECU 100 has motor drive circuits 15a, 15b, 15c, and 15d connected to an output interface. The wheel driving ECU 100 is provided so as to be able to exchange data with the steering ECU 50.

  The accelerator pedal sensor 27 detects a depression amount (depression angle) of an unillustrated accelerator pedal, and outputs an accelerator pedal signal representing the depression amount to the wheel drive ECU 100. The brake pedal sensor 28 detects a depression amount (depression angle) of a brake pedal (not shown), and outputs a brake pedal signal representing the depression amount to the wheel driving ECU 100.

The wheel drive ECU 100 outputs a control signal to the motor drive circuits 15a, 15b, 15c, 15d based on the accelerator pedal signal, the brake pedal signal, the shift position signal, and the wheel speed signal, and the drive motors 14a, 14b, 14c. 14d, a predetermined torque is generated and the wheels W _FL , W _FR , W _RL , W _RR are independently driven and controlled.

  The turning ECU 50 has a turning parking support function to be described later in addition to a normal turning control function. The turning ECU 50 performs normal turning control when the normal mode is selected by the selection operation of the operation input unit 25, and performs turning parking support control when the turning parking support mode is selected. Therefore, the steering ECU 50 stores a control program for performing normal steering control and a control program for performing turning parking support control separately in the ROM.

During normal turning control, the turning motors 12a, 12b, and 12c are set so that the turning angles of the wheels W _FL , W _FR , W _RL , and W _RR become the target turning angles corresponding to the steering wheel steering angle θh. , 12d are controlled. When performing the normal steering control, the steering ECU 50 performs target steering angles δ _FL *, δ _FR *, δ _RL * of the wheels W _FL , W _FR , W _RL , W _RR corresponding to the steering angle θh of the steering wheel. , Δ _RR * are stored in advance in the ROM as a target turning angle table, and the wheel W _FL , W _FR , W _RL , W _RR target turning angles δ _FL *, δ _FR *, δ _RL *, δ _RR * are calculated sequentially. Then, the actual turning angles δ _FL , δ _FR , δ _RL , δ _RR detected by the wheel steering angle sensors 21a, 21b, 21c, 21d and the target turning angles δ _FL *, δ _FR *, δ _RL *, [delta] _RR * and the deviation _{(δ FL * -δ FL, δ} FR * -δ FR, δ RL * -δ RL, δ RR * -δ RR) steering motor 12a in response to, 12b, 12c, to 12d A target current to be energized is set, and a control signal (for example, a PWM control signal) corresponding to the target current is output to the motor drive circuits 13a, 13b, 13c, and 13d. As a result, the steering motors 12a, 12b, 12c, and 12d are driven, and the turning angles of the wheels W _FL , W _FR , W _RL , and W _RR are the target turning angles δ _FL *, δ _FR *, δ _RL *. , Δ _RR *.

The target turning angles δ _FL *, δ _FR *, δ _RL *, and δ _RR * are set to a larger angle as the steering wheel steering angle θh increases, but the characteristics are changed according to the vehicle speed. It may be.

  Next, turning parking support control will be described. The turning ECU 50 switches from the normal turning control to the turning parking assistance control when the turning parking assistance mode is selected by the selection operation of the operation input unit 25. In the turning parking assist control, the steering angle of the wheel W is automatically set so that the vehicle does not require a steering operation and the vehicle advances along a predetermined turning locus.

  First, the turning operation of the vehicle by turning parking assistance control will be described with reference to FIG. Here, a case will be described in which the vehicle C is turned leftward and is put in the parking lot P from the top. The parking lot P is provided adjacent to the passage R, and is set to have vertical and horizontal sizes so that the direction orthogonal to the passage direction (the left-right direction in the drawing) is the vehicle front-rear direction. Hereinafter, the straight line including the boundary line on the right side of the parking lot P is referred to as a line L1, and the boundary line on the lower side of the passage R in the drawing is referred to as a line L2. Further, assuming that the outer shape of the vehicle C is rectangular in plan view, the right end of the vehicle front surface is called a right front corner portion A, and the right end of the rear end surface is called a right rear corner portion B.

  When the lateral width of the parking lot P and the lateral width of the passage R are narrow, as shown in FIG. 3B, the right rear corner portion B of the vehicle C is set so that the right front corner portion A of the vehicle C is along the line L1. When the vehicle is turned along the line L2, it is possible to enter the garage through a narrow entry space that is the limit of entry. Therefore, in the present embodiment, the vehicle C is turned so that such a vehicle turning locus is obtained.

  As shown in FIG. 3B, the driver matches the head surface of the vehicle C with the line L1, and also matches the right side surface (side surface opposite to the turning direction) of the vehicle C with the line L2. Stop C. The position of the vehicle C is an initial position for performing turning parking support control. In this case, the driver arranges the vehicle C inside the lines L1 and L2 with a certain margin so that the vehicle C does not cross the lines L1 and L2 outward (from the turning center to the outer diameter direction). Also good. In the following description, it is assumed that the leading surface of the vehicle C coincides with the line L1, and the right side surface (side surface opposite to the turning direction) of the vehicle C coincides with the line L2.

When the driver stops the vehicle C at this position, the driver operates the mode selection switch 25a of the operation input unit 25 to select the turning parking support mode. Then, turning parking support control is started by turning on the start switch 25b. By turning on the start switch 25b, the steering ECU 50 controls the steering motors 12a, 12b, 12c, and 12d so that the right front corner A of the vehicle C is along the line L1 and the vehicle C the right rear corner portion B along the line L2 as the vehicle C is turning, the wheels _{W FL, W FR, W RL} , the steering angle of W _RR, wheels _{W FL, W FR, W RL} , W RR The target turning angle is controlled according to the rolling distance.

That is, the right front corner portion A of the vehicle moves along a straight line (line L1) extending in the vehicle width direction through the right front corner portion A at the initial position, and the right rear corner portion B of the vehicle is the right rear corner at the initial position. The turning angles of the wheels W _FL , W _FR , W _RL , W _RR are adjusted so that the wheels W _FL , W _FR , W _RR , and W _RR move along a straight line (line L2) extending in the vehicle longitudinal direction through the part B. It is set as the target steering angle corresponding to the rolling distance W _RR.

  When the vehicle C is stopped inward from the lines L1 and L2, the right front corner A and the right rear corner B of the vehicle C are the lines L1 and L2 drawn inward from the lines L1 and L2 correspondingly. It moves on parallel straight lines.

During the turning parking assist control, the driver loosens the depression force of the brake pedal, advances the vehicle in a creep state, and does not perform any steering wheel operation. When the vehicle C turns 90 °, the steering ECU 50 returns the wheels W _FL , W _FR , W _RL , W _RR to the neutral position and ends the turning parking assist control. As a result, the right side surface of the vehicle C is aligned in parallel with the line L1.

In order to realize such a turning movement of the vehicle, the steering ECU 50 sets the target turning angle δ with respect to the rolling distances D _FL , D _FR , D _RL , D _RR of the wheels W _FL , W _FR , W _RL , W _RR. Calculate _FL *, δ _FR *, δ _RL *, and δ _RR *. The relationship of the target turning angles δ _FL *, δ _FR *, δ _RL *, δ _RR * with respect to the rolling distances D _FL , D _FR , D _RL , D _RR of the wheels W _FL , W _FR , W _RL , W _RR It is set in advance and stored in storage means such as a ROM. Hereinafter, the wheels _{W FL, W FR, W RL} , rolling distance D _FL of _{W RR, D FR, D RL} , the target steering angle [delta] _FL * for _{D RR, δ FR *, δ} RL *, the [delta] _RR * This will be described with reference to FIG.

Consider XY coordinates where the position of the right rear corner B at the initial position of the vehicle is the origin (0, 0), the longitudinal direction of the vehicle at the initial position is the X direction, and the vehicle width direction is the Y direction. Assuming that the coordinates of the right front corner A when the right rear corner B moves by the distance x in the X direction is (x _A , y _A ) and the angle of the vehicle longitudinal axis with respect to the x axis is θ, the following equation Is derived. In the formula, L represents the total length of the vehicle (see FIG. 5).

右前輪接地中心点ＦＲの初期位置からの転動距離をＤ_FRとし、右前輪Ｗ_FRのｘ軸となす角度、つまり、右前輪接地中心点ＦＲの移動していく方向に右前輪Ｗ_FRを向けた場合の右前輪Ｗ_FRのｘ軸とのなす角度をθ_FRとすると、以下の式が導き出される。

If the coordinates of the right front wheel ground contact center point FR are (x _FR , y _FR ), the following formula is derived. In the equation, L represents the total length of the vehicle, W represents the full width of the vehicle, WB represents the wheel base, TR represents the tread, FOH represents the front overhang, and ROH represents the rear overhang (see FIG. 5).

The rolling distance from the initial position of the right front wheel contact center point FR and D _FR, angle between x-axis of the right front wheel W _FR, that is, the right front wheel W _FR in a direction moves the right front wheel contact center point FR when the angle between x-axis of the right front wheel W _FR when directed to theta _FR, the following equation is derived.

Because the actual rolling distance from the wheel speed omega _FR of the right front wheel W _FR detected by the wheel speed sensor 22b of the right front wheel W _FR can be calculated, since the actual rolling distance and wherein the right front wheel W _FR (1) x is calculated, and θ _FR is calculated by substituting the calculated x into equation (2).
In this case, the target turning angle δ _FR * of the right front wheel W _FR can be calculated as δ _FR * = θ _FR −θ. Therefore, it is possible to uniquely set a target steering angle [delta] _FR * from rolling distance D _FR of the right front wheel W _FR.

Left front wheel W _FL, the right rear wheel W _RR, similarly for the left rear wheel W _RL, left front wheel W _FL, the right rear wheel W _RR, rolling distance D _FL of the left rear wheel W _RL, D _RR, from D _RL The target turning angle δ _FL *, δ _RR *, δ _RL * can be calculated.

また、左前輪接地中心点ＦＬの初期位置からの転動距離をＤ_FL、左前輪Ｗ_FLのｘ軸となす角度をθ_FLとすると以下の式が導き出される。

これにより、左前輪Ｗ_FLの転動距離Ｄ_FLから目標転舵角δ_FL＊（＝θ_FL−θ）を一義的に設定することができる。 For the left front wheel W _FL , if the coordinates of the left front wheel ground contact center point FL are (x _FL , y _FL ), the following equations are derived.

Further, when the rolling distance from the initial position of the left front wheel ground contact center point FL is D _FL and the angle between the left front wheel W _{FL and} the x axis is θ _FL , the following equation is derived.

Thereby, the target turning angle δ _FL * (= θ _FL −θ) can be uniquely set from the rolling distance D _FL of the left front wheel W _FL .

また、右後輪接地中心点ＲＲの初期位置からの転動距離をＤ_RR、右後輪Ｗ_RRのｘ軸となす角度をθ_RRとすると以下の式が導き出される。

これにより、右後輪Ｗ_RRの転動距離Ｄ_RRから目標転舵角δ_RR＊（＝θ_RR−θ）を一義的に設定することができる。 For the right rear wheel W _RR , if the coordinates of the right rear wheel ground contact center point RR are (x _RR , y _RR ), the following equations are derived.

Further, when the rolling distance from the initial position of the right rear wheel ground contact center point RR is D _RR and the angle between the right rear wheel W _{RR and} the x axis is θ _RR , the following equation is derived.

Thereby, the target turning angle δ _RR * (= θ _RR −θ) can be uniquely set from the rolling distance D _RR of the right rear wheel W _RR .

また、左後輪接地中心点ＲＬの初期位置からの転動距離をＤ_RL、左後輪Ｗ_RLのｘ軸となす角度をθ_RLとすると以下の式が導き出される。

これにより、左後輪Ｗ_RLの転動距離Ｄ_RLから目標転舵角δ_RL＊（＝θ_RL−θ）を一義的に設定することができる。 Further, for the left rear wheel W _RL , when the coordinates of the left rear wheel ground contact center point RL are (x _RL , y _RL ), the following formula is derived.

Further, when the rolling distance from the initial position of the left rear wheel ground contact center point RL is D _RL and the angle between the left rear wheel W _{RL and} the x axis is θ _RL , the following expression is derived.

Thereby, the target turning angle δ _RL * (= θ _RL −θ) can be uniquely set from the rolling distance D _RL of the left rear wheel W _RL .

Thus, the target turning angles δ _FL *, δ _FR *, δ _RL *, δ with respect to the rolling distances D _FL , D _FR , D _RL , D _RR of the wheels W _FL , W _FR , W _RL , W _{RR Since RR} * is uniquely determined, reference is made in advance to associate the rolling distances D _FL , D _FR , D _RL , D _RR with the target turning angles δ _FL *, δ _FR *, δ _RL *, δ _RR *. The table may be stored in the ROM, and the target turning angles δ _FL *, δ _FR *, δ _RL *, δ _RR * may be obtained from this reference table during turning parking support control.

FIG. 6 shows the movement trajectory of the wheel ground contact center points FR, FL, RR, RL when the vehicle is turned 90 ° by the turning parking assist control. In the figure, the movement locus of the ground center point of the solid line left front wheel W _FL, movement locus of the broken line grounding the center point of the right front wheel W _FR, the movement locus of the ground center point of the one-dot chain line is the left rear wheel W _RL, 2 Dotted lines represent the movement trajectories of the contact center point of the right rear wheel _WRR .

Further, FIG. 7, the wheels _{W FL, W FR, W RL} , rolling distance D _FL of _{W RR, D FR, D RL} , D RR and the target steering angle _{δ FL *, δ FR *,} δ RL *, This represents the relationship with δ _RR *. In the figure, the solid line indicates the target turning angle δ _FL * with respect to the rolling distance D _FL of the left front wheel W _FL , and the broken line indicates the target turning angle δ _FR * with respect to the rolling distance D _FR of the right front wheel W _FR. The target turning angle δ _RL * with respect to the rolling distance D _RL of the left rear wheel W _RL * The two-dot chain line represents the target turning angle δ _RR * with respect to the rolling distance D _RR of the right rear wheel W _RR . Therefore, the characteristics shown in FIG. 7 are stored in the ROM as a reference table, and the target turning angles δ _FL *, δ _FR *, δ _RL *, δ _RR * are obtained from this reference table during turning parking support control. Can be.

  Next, turning parking support control processing executed by the steering ECU 50 will be described. FIG. 8 shows a turning parking assistance control routine executed by the steering ECU 50. This turning parking assist control routine is stored as a control program in the ROM of the steering ECU 50.

  When the driver enters the parking lot, the driver stops the vehicle at a position where the front surface of the vehicle is parallel to the line L1 and the right side surface of the vehicle is parallel to the line L2, and the mode of the operation input unit 25 is The turning switch assist mode is selected by operating the selection switch 25a. At this time, the turning direction (right or left) of the vehicle is selected by the turning direction selection switch 25c. When the turning parking assistance mode is selected, the turning parking assistance control routine is activated. When the vehicle is retracted and put into the garage, the vehicle is stopped at a position where the rear end of the vehicle is parallel to the line L1 and the left side of the vehicle is parallel to the line L2. It is only necessary to operate the 25 mode selection switch 25a to select the turning parking support mode.

  When this control routine is started, the steering ECU 50 reads the input status of the start switch 25b of the operation input unit 25 in step S11, and determines whether or not the start switch 25b is in an on state in step S12. . The processes in steps S11 and S12 are repeated until the start switch 25b is turned on.

  When the driver turns on the start switch 25b, the determination in step S12 is “YES”, and the steering ECU 50 advances the process to step S13. After turning on the start switch 25b, the driver weakens the stepping force of the brake and gradually moves the vehicle in the creep state.

  In step S13, the steering ECU 50 reads the setting signal set by the turning direction selection switch 25c of the operation input unit 25 and the shift position signal detected by the shift position sensor 26.

Subsequently, the steering ECU 50 reads the wheel speeds ω _FL , ω _FR , ω _RL , and ω _RR detected by the wheel speed sensors 22a, 22b, 22c, and 22d in step S14, and the vehicle initial position in step S15. The rolling distances D _FL , D _FR , D _RL , D _RR of the wheels W _FL , W _FR , W _RL , W _RR from (the vehicle position when the start switch 25b is turned on) are calculated. The rolling distances D _FL , D _FR , D _RL , D _RR are obtained from the outer diameter of the tire and the wheel speeds ω _FL , ω _FR , ω _RL , ω _RR .

Subsequently, in step S16, the steering ECU 50 determines the respective targets corresponding to the rolling distances D _FL , D _FR , D _RL , D _RR of the wheels W _FL , W _FR , W _RL , W _RR as described above. Calculate the turning angle δ _FL *, δ _FR *, δ _RL *, δ _RR *. The target turning angles δ _FL *, δ _FR *, δ _RL *, δ _RR * may be obtained from the above-described calculation formula, or may be obtained from a reference table storing characteristics as shown in FIG. Good. The turning ECU 50 that executes step S16 corresponds to the target turning angle setting means in the present invention.

In this case, target turning angles δ _FL *, δ _FR *, δ _RL *, δ _RR * are set according to the turning direction and the shift position read in step S13. That is, since the target turning trajectory is symmetrical between the right turn and the left turn, the target turning angles δ _FL *, δ _FR *, δ _RL *, and δ _RR * are set correspondingly. For example, when turning right, the target turning angle of the right wheels W _FR and W _RR when turning right is the same size (absolute value) as the turning angle of the left wheels W _FL and W _RL when turning left. The target turning angles of the left wheels W _FL and W _RL are set to the same magnitude (absolute value) as the target turning angles of the right wheels W _FR and W _RR when turning left. In addition, the forward turn that enters the garage from the front of the vehicle and the reverse turn that enters the garage from the rear of the vehicle travel in the opposite direction on the same trajectory, so the initial position in the forward turn is the end position in the reverse turn, and the forward turn The target turning angles δ _FL *, δ _FR *, δ _RL *, and δ _RR * are set so that the end position at is the start position for reverse turning.

Subsequently, in step S17, the turning ECU 50 turns the wheels W _FL , W _FR , W _RL , W _RR turning angles δ _FL , δ _FR , detected by the wheel rudder angle sensors 21a, 21b, 21c, 21d. Read δ _RL and δ _RR . Hereinafter, the detected turning angles δ _FL , δ _FR , δ _RL , δ _RR are referred to as actual turning angles δ _FL , δ _FR , δ _RL , δ _RR .

Subsequently, in step S18, the turning ECU 50 calculates the target turning angle δ _FL *, δ _FR *, δ _RL *, δ _RR * and the actual turning angle δ _FL , δ _FR , δ _RL , δ _RR . Based on the deviation Δδ (δ _FL * −δ _FL , δ _FR * −δ _FR , δ _RL * −δ _RL , δ _RR * −δ _RR ), the steering motors 12 a, 12 b, 12 c and 12 d should be energized. A target current is set, and a control signal (for example, a PWM control signal) corresponding to the target current is output to the motor drive circuits 13a, 13b, 13c, and 13d. Thus, the directions of the wheels W _FL , W _FR , W _RL , W _RR are controlled so as to become the target turning angles δ _FL *, δ _FR *, δ _RL *, δ _RR *.

In the steering ECU 50, the magnitude (absolute value) of the target turning angles δ _FL *, δ _FR *, δ _RL *, δ _RR * exceeds 90 °, which is the steerable range of the steering mechanism 10. In this case, the steering angle obtained by reversing the steering direction 180 degrees to the left and right is set as the target steering angle of the wheel W. For example, when the target turning angle is 100 ° to the left, the target turning angle is reversed 180 ° to the right and the final target turning angle is set to 80 ° to the right. When the steered ECU 50 is set so that the target steered angle is reversed 180 ° to the left and right in this way, the steered motor 12 is driven and controlled in step S18, and at the same time, the wheel drive ECU 100 is controlled. An inversion command for inverting the rotation driving direction of W is output. When the inversion command is input, the wheel driving ECU 100 inverts the rotational driving direction of the wheel W.

  Therefore, even when the calculated target turning angle exceeds the steerable range of the turning mechanism 10, the wheel can be rolled along the target traveling direction. The target turning angle shown in the reference table of FIG. 7 is set by reversing the turning direction left and right by 180 ° when the calculated target turning angle exceeds 90 °. The steering ECU 50 that performs such inversion processing corresponds to the inversion control means of the present invention. In the case where the steering mechanism 10 is configured to be able to steer the wheel W over the entire range of the target turning angle, it is not necessary to perform the reversing process.

  Subsequently, the steering ECU 50 determines in step S19 whether or not the 90 ° turn of the vehicle has been completed. For example, it is determined whether or not the rolling distance D of a specific wheel W has reached the end distance (the rolling distance of the wheel required for the vehicle to turn 90 °). If the turning of the vehicle is not completed, the process returns to step S13.

Thus, the steering ECU 50 repeats the processing from step S13 to step S19 at a predetermined short period until the turning of the vehicle is completed. Thus, the vehicle has wheels W _FL , W _FR , W _RL , W _RR whose target turning angles δ _FL *, δ _FR *, δ _RL correspond to the rolling distances D _FL , D _FR , D _RL , D _RR. *, Δ _RR *, and as shown in FIG. 3B, the right front corner A moves along the line L1 in the parking direction, and the right rear corner B moves right along the line L2. Turn to move. When the vehicle turns 90 ° from the initial position, the steering ECU 50 determines that the turn is completed in step S19, and advances the process to step S20.

In step S20, the steering ECU 50 drives the steering motors 12a, 12b, 12c, and 12d to direct the wheels W _FL , W _FR , W _RL , and W _RR to the neutral position (0 °). That is, the control signals are output to the motor drive circuits 13a, 13b, 13c, and 13d so that the actual turning angles δ _FL , δ _FR , δ _RL , and δ _RR become 0 °, thereby turning the steering motors 12a, 12b, and 12c. , 12d.

The turning parking assist control routine ends when the steering to the neutral position of the wheels W _FL , W _FR , W _RL , W _RR is completed. The turning ECU 50 switches to the normal turning control mode when the turning parking support control routine ends. At the end of the turning parking support control routine, the vehicle has the right side surface parallel to the line L1, as shown in FIG. The driver can complete the garage entry by moving the vehicle forward from this state to the back of the parking lot. In addition, it is good to provide the alerting | reporting apparatus which announces that the turning parking assistance mode was complete | finished with respect to a driver | operator at the time of completion | finish of this turning parking assistance control routine.

  In addition, when taking out a vehicle from a parking lot, a vehicle is made to reverse | retreat to the completion | finish position of the turning parking assistance control mentioned above. That is, the vehicle is stopped at a position where the right side surface of the vehicle is aligned parallel to the line L1 and the rear end surface of the vehicle is aligned parallel to the line L2. At this time, the shift lever is kept in the retracted position. Then, the turning parking support mode is selected by the mode selection switch 25a of the operation input unit 25, and the start switch 25b is turned on to move the vehicle in the opposite direction on the same turning locus as when the garage is put by turning parking support control. Can be made.

  During the execution of the turning parking assist control routine, the steering control of the wheels W is performed regardless of the operation of the steering handle 40. However, when the steering handle 40 is suddenly rotated halfway, the driving is performed. The turning parking support control routine may be terminated assuming that the person has made some kind of intention display. For example, an end means is provided for reading the steering torque Th detected by the steering torque sensor 24 and ending the turning parking assistance control routine when the read steering torque Th is a large value exceeding the reference value Th0. When the driver finds an obstacle or the like during the turn, the driver may strongly rotate the steering handle 40 in a reflective manner. Therefore, the operation performed by the driver can be detected and automatically switched to the normal mode. Further, instead of the configuration in which the driving assistance for parking is stopped by the driver's steering and the mode is switched to the normal mode, control may be made to return the route that has just been taken so that the vehicle surely returns to the original position.

According to the turning parking assist control routine described above, the vehicle traveling direction side corner (right front corner A) opposite to the turning direction passes through the traveling direction side corner (right front corner A) at the initial position. The vehicle travels along a straight line extending in the direction (line L1), and the counter-traveling direction side corner (right rear corner B) of the vehicle opposite to the turning direction is the counter-traveling direction side corner (right rear) at the initial position. A target corresponding to the rolling distance of each wheel W _FL , W _FR , W _RL , W _RR so as to move toward the vehicle traveling direction side along a straight line (line L2) extending in the vehicle longitudinal direction through the corner B). The turning angle δ _FL *, δ _FR *, δ _RL *, δ _RR * is set. Therefore, even when the approach path to the parking lot is a narrow L-shaped course, the vehicle can be easily put into the parking lot. That is, the vehicle can be steered only by placing the vehicle parallel to the passage so that the right front corner A of the vehicle is positioned at the corner of the L-shaped course (the intersection of the line L1 and the line L2). It can be left to the turning parking assistance control which ECU50 for vehicles performs. Accordingly, it is possible to park the vehicle by entering the narrow L-shaped course close to the limit of the vehicle body size without operating the steering wheel. As a result, garage entry into a narrow parking lot is very easy.

  Of course, it is not necessary for the head and the side of the vehicle to coincide with the lines L1 and L2, and the vehicle may be arranged inside the lines L1 and L2 with a certain margin. In this case, the right front corner portion A and the right rear corner portion B of the vehicle move on a straight line parallel to the lines L1 and L2 drawn inward from the lines L1 and L2.

Further, the target turning angles δ _FL *, δ _FR *, δ _RL * are uniquely determined with respect to the rolling distances D _FL , D _FR , D _RL , D _{RR of} the wheels W _FL , W _FR , W _RL , W _RR . , Δ _RR * is set to always turn the vehicle from the initial position with a constant trajectory, so that it is not necessary to sequentially set the turning center of the vehicle and the control is not complicated. Therefore, a high processing capacity is not required for the microcomputer used in the steering ECU 50. Also, the development man-hours can be reduced.

  In addition, since the vehicle can turn without protruding outward from the straight line extending in the vehicle width direction and the straight line extending in the vehicle front-rear direction at the initial position of the vehicle, the driver is mainly focused on the inner side of the vehicle turning direction. The periphery monitoring sensor can be omitted or simplified. As a result, parking assistance can be implemented at low cost.

Also, since the four-wheel W _FL , W _FR , W _RL and W _RR are applied to a four-wheel independent drive system vehicle that independently rotates, the steering angle of the wheel W is maintained at a large steering angle. Thus, the vehicle can be turned well.

  The first embodiment described above is applied to a vehicle equipped with a four-wheel independent steering type steering device, but the left and right wheels cannot be independently turned, and only the turning angles of the front and rear wheels are independently adjusted. The present invention can also be applied to a vehicle including a front and rear wheel independent steering type steering device. The setting of the target turning angle in this case will be described.

As shown in FIG. 9, a virtual front wheel W _F (hereinafter referred to as a virtual front wheel W _F ) and a virtual rear wheel W _R (hereinafter referred to as a virtual rear wheel W _R ) are considered on the vehicle center axis. The vehicle is similar to the first embodiment, along the front right corner portion A is the line L1 of the vehicle, and the virtual wheel W _F as the right rear corner B of the vehicle vehicle turns along a line L2 target steering angle for rolling distance, calculates a target steering angle for rolling distance of the virtual rear wheel W _R.

Consider XY coordinates where the position of the right rear corner B at the initial position of the vehicle is the origin (0, 0), the longitudinal direction of the vehicle at the initial position is the X direction, and the vehicle width direction is the Y direction. When the coordinates of the right front corner A when the right rear corner B moves by the distance x is (x _A , y _A ) and the angle of the vehicle longitudinal axis with respect to the x axis is θ, the following equation is derived. . In the formula, L represents the total length of the vehicle (see FIG. 5).

仮想前輪Ｗ_Fの接地中心点Ｆの初期位置からの転動距離をＤ_Fとし、仮想前輪Ｗ_Fのｘ軸となす角度、つまり、仮想前輪接地中心点Ｆの移動していく方向に仮想前輪Ｗ_Fを向けた場合の仮想前輪Ｗ_Fのｘ軸とのなす角度をθ_Fとすると、以下の式が導き出される。

従って、第１実施形態と同様に、仮想前輪Ｗ_Fの転動距離Ｄ_Fに対する目標転舵角δ_F（＝θ_F−θ）を設定することができる。 Further, coordinates (x _F, y _F) of the ground center point F of the virtual front wheel W _F When the following equation is derived. In the equation, L represents the total length of the vehicle, W represents the full width of the vehicle, WB represents the wheel base, FOH represents the front overhang, and ROH represents the rear overhang (see FIG. 5).

The rolling distance from the initial position of the ground center point F of the virtual front wheel W _F and D _F, the angle formed between the x-axis of the virtual front wheel W _F, that is, the virtual wheel in the direction moves the virtual front wheel contact center point F when the angle between x-axis of the virtual front wheel W _F where with its W _F and theta _F, the following equation is derived.

Therefore, as in the first embodiment, it is possible to set the virtual wheel W target turning angle for rolling distance D _F of the _{F δ F (= θ F -θ} ).

In turning the parking assist control in, the average value of the rolling distance D _FR of the rolling distance D _FL and the right front wheel W _FR of the left front wheel W _FL, a right front wheel target steering angle [delta] _F corresponding to the mean value The steering control may be performed by setting the target turning angles δ _FL and δ _FR of W _FL and W _FR .

また、仮想後輪接地中心点Ｒの初期位置からの転動距離をＤ_R、仮想後輪Ｗ_Rのｘ軸となす角度をθ_Rとすると以下の式が導き出される。

従って、仮想後輪Ｗ_Rの転動距離Ｄ_Rに対する目標転舵角δ_R（＝θ_R−θ）を設定することができる。 Similarly, for the virtual rear wheel W _R , if the coordinates of the virtual rear wheel ground contact center point R are (x _R , y _R ), the following formula is derived.

Further, when the rolling distance from the initial position of the virtual rear wheel ground contact center point R is D _R and the angle between the virtual rear wheel W _{R and} the x axis is θ _R , the following equation is derived.

Therefore, the target turning angle δ _R (= θ _R −θ) with respect to the rolling distance D _R of the virtual rear wheel W _R can be set.

In turning the parking assist control in, the average value of the rolling distance D _FR of the rolling distance D _RL and the right rear wheel W _RR of the left rear wheel W _RL, a target steering angle [delta] _R corresponding to the average value The left and right rear wheels W _RL and W _RR may be set as target turning angles δ _RL and δ _RR to perform the turning control.

Second Embodiment
Next, a vehicle parking assistance apparatus as a second embodiment will be described. In the first embodiment described above, when turning parking support control is started, the vehicle enters a narrower course so that one side surface (right side surface in the example of FIG. 3) of the vehicle is brought to the outside line (line L2) of the passage. However, when the turning parking support control is started, the wheels W protrude from the vehicle body as shown in FIG. For this reason, when there is an obstacle such as a wall surface on the line L2, it is necessary to stop the vehicle on the inner side of the line L2 by the amount that the wheel W protrudes.

For example, it can be said that the parking approach course shown in FIG. However, turning the parking assist to be steered to the right front wheel W _FR is approximately 90 ° when the control was started, as shown in FIG. 11 (B), asked by an amount vehicle protrude wheels W inward of the line L2 When the vehicle starts turning, the left side of the vehicle hits the entrance end of the parking lot during the turn (G portion in the figure) and parking is impossible.

  Therefore, in the second embodiment, in order to prevent the wheels W from protruding outward from the vehicle body, the steering mechanism 10 is moved in the vehicle width direction for each wheel W as shown in FIG. A wheel retractor 30 for retracting the wheel W is provided.

  The wheel retracting device 30 is provided directly above the steering motor 12, a slide holding housing 31 that holds the steering motor 12 slidably in the vehicle width direction, and a ball screw provided in the slide holding housing 31. A mechanism 32 and an electric motor 33 (hereinafter referred to as a retracting motor 33) for driving the ball screw mechanism 32 are provided.

  The slide holding housing 31 is a box that is fixed to a suspension device (not shown) and is long in the vehicle width direction. A slide hole 31a is formed on the lower surface in the vehicle width direction, and the steering motor 12 is moved along the slide hole 31a. And keep it movable.

  The ball screw mechanism 32 includes a ball screw 32a that is rotatably supported by the slide holding housing 31, and a ball screw nut 32b having a female screw portion that engages with a male screw portion formed on the ball screw 32a. The ball screw 32a is connected to the output shaft of the retracting motor 33 via a reduction gear (not shown). On the other hand, the ball screw nut 32b is connected to the steering motor 12 via a connecting member 32c that passes through the slide hole 31a.

  In the wheel retractor 30, the rotational motion of the ball screw 32a is converted into linear motion in the vehicle width direction of the ball screw nut 32b. Since the ball screw nut 32b and the steering motor 12 are integrally connected, the position of the steering mechanism 10 is changed in the vehicle width direction with respect to the vehicle body by controlling the rotation of the pull-in motor 33. Can do. Therefore, the wheel W can be drawn in the vehicle width direction with respect to the vehicle body.

Incidentally, the pull motor 33 provided in each wheel retraction apparatus 30 to be driven and controlled independently, hereafter referred to as motor 33a for attracting the motor for displacing the left front wheel W _FL, to displace the right front wheel W _FR motor a pull-in motor 33b, motor 33c for attracting the motor for displacing the left rear wheel W _RL, referred to as a motor 33d for attracting the motor for displacing the right rear wheel W _RR.

  As shown in FIG. 14, the retracting motors 33a, 33b, 33c, and 33d are connected to motor drive circuits 16a, 16b, 16c, and 16d, respectively. The motor drive circuits 16a, 16b, 16c, and 16d (hereinafter simply referred to as the motor drive circuit 16 when collectively referred to) include a bridge circuit or the like (for example, an inverter circuit) configured by a plurality of switching elements. The retracting motors 33a, 33b, 33c, and 33d are rotationally driven in a forward / reverse manner with a voltage corresponding to a control signal (for example, a PWM control signal) output from the rudder ECU 50.

Further, the steering ECU 50 is connected to movement amount sensors 29 a, 29 b, 29 c, and 29 d that detect the amount of pulling movement of the steering mechanism 10 in each wheel pulling device 30. In the present embodiment, a rotation angle sensor (not shown) that detects a motor rotation angle (rotation position) is used as the movement amount sensors 29a, 29b, 29c, and 29d. The movement amount sensors 29a, 29b, 29c, and 29d are incorporated in the pulling motors 33a, 33b, 33c, and 33d, and signals representing the pulling movement amounts i _FL , i _FR , i _RL , and i _RR of the respective steering mechanisms 10. Output to the steering ECU 50. Hereinafter, the pull-in movement amounts detected by the movement amount sensors 29a, 29b, 29c, and 29d are referred to as actual pull-in movement amounts i _FL , i _FR , i _RL , i _RR . The pull-in movement amount represents the distance that the steering mechanism 10 has moved inward in the vehicle width direction from the normal position, with the state where the steering mechanism 10 is positioned on the outermost side in the vehicle width direction.

  In the wheel retracting device 30, the amount of retracting movement is set according to the turning angle of the wheel W. In the present embodiment, the pull-in movement amount is set so that the outer end of the wheel W (tire) in the vehicle width direction is positioned on the same vertical plane extending in the vehicle front-rear direction regardless of the change in the turning angle. . FIGS. 13A and 13B are schematic plan views for explaining the moving operation of the steering mechanism 10 that is displaced inward in the vehicle width direction as the turning angle of the wheel W increases. FIG. 13A is a neutral position, and FIG. A steering angle of 20 °, (C) represents a positional relationship between the wheel W and the steering mechanism 10 at a steering angle of 90 °.

  The steered mechanism 10 is disposed at the outermost position in the vehicle width direction in the neutral position. At this time, the sidewall surface WS, which is the outer end of the wheel W (tire), is positioned on the same plane as the outer surface BS of the vehicle body. When the wheel W is steered from the neutral position, as shown in (B), the corner portion WC serving as the outer end in the vehicle width direction of the wheel W (tire) The steering mechanism 10 is pulled inward in the vehicle width direction so as to be positioned on a plane formed by the sidewall surface WS. Further, when the wheel W is steered and the turning angle becomes 90 °, as shown in (C), the tread portion WT serving as the outer end in the vehicle width direction of the wheel W (tire) becomes the wheel W ( The steering mechanism 10 is drawn inward in the vehicle width direction so as to be positioned on a plane formed by the sidewall surface WS of the tire). By the way, when the turning angle is (90 ° −φ), the turning mechanism 10 is at the position where it is drawn inwardly in the vehicle width direction. In addition, φ is an angle determined by the tire outer diameter d and the tire width e by a calculation formula described later.

  Thus, since the outer end in the vehicle width direction of the wheel W is located on the same vertical plane (outer side surface BS of the vehicle body) extending in the vehicle front-rear direction regardless of the change in the steering angle, the wheel W is outside the vehicle body. Does not protrude. Further, the wheel W can be positioned as far as possible in the vehicle width direction as long as it does not protrude outside the vehicle body.

  In the second embodiment, the turning angle is controlled according to the rolling distance of the wheel W, and the pull-in movement amount of the wheel W is controlled according to the turning angle. Therefore, the relationship among the rolling distance of the wheel W, the turning angle, and the pulling movement amount will be described.

但し、φは次式のように表される角度である。

As shown in FIG. 16, the outer diameter of the tire is d, the width of the tire is e, and the horizontal section at the center position of the tire is a rectangle. When the turning angle is 0 ° (neutral position), the sidewall surface WS of the tire is located on the same plane as the outer side surface BS of the vehicle body, and always in the vehicle width direction of the tire with respect to the change of the turning angle. When the pull-in movement amount is set so that the outer end is located on the same plane as the outer surface BS of the vehicle body, the pull-in movement amount i is obtained by the following equation.

However, φ is an angle represented by the following equation.

As shown in FIG. 15, the position of the right rear corner B at the initial position of the vehicle is the origin (0, 0), the front-rear direction of the vehicle at the initial position is the X direction, and the vehicle width direction is the Y direction. Consider the coordinates. Assuming that the coordinates of the right front corner A when the right rear corner B moves by the distance x in the X direction is (x _A , y _A ), and θ is the angle with respect to the x axis of the vehicle, the following equation is derived. Note that L, W, TR, FOH, and ROH in the following expressions are used in the same meaning as in the first embodiment.

右前輪接地中心点ＦＲの初期位置からの転動距離をＤ_FRとし、右前輪Ｗ_FRのｘ軸となす角度、つまり、右前輪接地中心点ＦＲの移動していく方向に右前輪Ｗ_FRを向けた場合の右前輪Ｗ_FRのｘ軸とのなす角度をθ_FRとすると、以下の式が導き出される。

右前輪Ｗ_FRの転舵角δ_FRは、θ_FR−θとして表すことができるため、式（４）から

If the coordinates of the right front wheel ground contact center point FR are (x _FR , y _FR ), the following equations are derived.

The rolling distance from the initial position of the right front wheel contact center point FR and D _FR, angle between x-axis of the right front wheel W _FR, that is, the right front wheel W _FR in a direction moves the right front wheel contact center point FR when the angle between x-axis of the right front wheel W _FR when directed to theta _FR, the following equation is derived.

Since the turning angle δ _FR of the right front wheel W _FR can be expressed as θ _FR −θ, from the equation (4)

Equation (5), since the equation for the unknowns [delta] _FR, solving this [delta] _FR is obtained. The rolling distance D _FR is also obtained by substituting the obtained δ _FR into the equation (3). Since the tire shape is known in advance, the pull-in movement amount i is also obtained. Therefore, the target turning angle δ _FR * corresponding to the rolling distance D _FR of the right front wheel W _FR and the target pulling movement amount i _FR * can be set in advance.

Similarly, the right rear wheel W _RR, it is possible to calculate the right rear wheel W rolls distance D target steering angle from the _RR [delta] _RR * and the target of the _RR pull movement amount i _RR *. Note that the wheel W in the turning direction (in this example, the left front wheel W _FL and the left rear wheel W _RL ) does not need to be pulled in to the vehicle body side, so the target pull-in movement amount is zero, which is the same setting as in the first embodiment. It becomes.

また、右後輪接地中心点ＲＲの初期位置からの転動距離をＤ_RR、右後輪Ｗ_RRのｘ軸となす角度をθ_RRとすると以下の式が導き出される。

ここで、右後輪Ｗ_RRの転舵角δ_RRは、θ_FR−θとして表すことができるため、

これら式を解くことにより、右後輪Ｗ_RRの転動距離Ｄ_RRに応じた目標転舵角δ_RR＊、および、目標引き込み移動量ｉ_RR＊を予め設定しておくことができる。 With respect to the right rear wheel W _RR , when the coordinates of the right rear wheel ground contact center point RR are (x _RR , y _RR ), the following equations are derived.

Further, when the rolling distance from the initial position of the right rear wheel ground contact center point RR is D _RR and the angle between the right rear wheel W _{RR and} the x axis is θ _RR , the following equation is derived.

Here, since the turning angle δ _RR of the right rear wheel W _RR can be expressed as θ _FR −θ,

By solving these equations, the target turning angle δ _RR * and the target pulling movement amount i _RR * corresponding to the rolling distance D _RR of the right rear wheel W _RR can be set in advance.

Thus, the wheels _{W FL, W FR, W RL} , W RR rolling distance D _FL of, D _FR, D _RL, for D _RR, the target steering angle _{δ FL *, δ FR *,} δ RL *, δ RR * In addition, the relationship between the target pulling movement amounts i _RL *, i _FR *, i _RL *, and i _RR * is uniquely determined. Therefore, this correspondence is stored in the ROM as a reference table, and the target turning angles δ _FL *, δ _FR *, δ _RL *, δ _RR * are referred to by referring to the reference table during the execution of the turning parking support control. In addition, the target pulling movement amounts i _RL *, i _FR *, i _RL *, i _RR can be obtained.

  Next, turning parking support control processing executed by the steering ECU 50 in the second embodiment will be described. FIG. 17 shows a turning parking assistance control routine executed by the steering ECU 50 according to the second embodiment. This turning parking support control routine adds steps S21 to S23 between step S18 and step S19 of the turning parking support control routine (FIG. 8) in the first embodiment, and replaces step S20 with step S20. S24 is performed. Hereinafter, the same processes as those in the turning parking support control routine of the first embodiment are denoted by the same step symbols in the drawings, and only a brief description will be given, and different portions will be described in detail.

When the turning ECU 50 detects that the start switch 25b is turned on (S12: YES), the turning ECU 50 reads the turning direction setting signal and the shift position signal (S13), and then the wheel speed sensors 22a, 22b, 22c, 22d. The rolling distances D _FL , D _FR , D _RL , D _RR of the wheels W _FL , W _FR , W _RL , W _RR are calculated from the wheel speeds ω _FL , ω _FR , ω _RL , ω _RR detected by S (S14). , S15). Subsequently, target turning angles δ _FL *, δ _FR *, δ _RL *, and δ _RR * corresponding to the rolling distances D _FL , D _FR , D _RL , D _RR are set (S16). These target turning angles δ _FL *, δ _FR *, δ _RL *, δ _RR * are values calculated by taking in the amount of pulling movement as described above, and are reference tables corresponding to the turning direction and the shift position. Sought with reference to

Subsequently, the turning ECU 50 detects the actual turning angles δ _FL , δ _FR , δ _RL , δ _RR and the target turning angles δ _FL *, δ _FR detected by the wheel steering angle sensors 21a, 21b, 21c, 21d. *, Δ _RL *, δ _RR * Deviation Δδ (δ _FL *-δ _FL , δ _FR *-δ _FR , δ _RL *-δ _RL , δ _RR *-δ _RR ) , 12b, 12c, 12d are controlled (S17, S18).

Subsequently, in step S21, the steering ECU 50 calculates a target pulling movement amount i _FR *, i _RR * (or i _FL *, i _RL *) of the front and rear wheels opposite to the turning direction. For example, when turning left, the target pulling movement amounts i _FR * and i _RR * of the right front and rear wheels W _FR and W _RR are calculated. This calculation is calculated from the turning angle δ and the tire shape (d, e) as described above. In this case, either the target turning angle or the actual turning angle may be used as the turning angle δ. Alternatively, a reference table in which a correspondence relationship between the turning angle and the target pull-in movement amount is set may be stored in the ROM, and the target pull-in amount may be obtained with reference to the reference table.

Subsequently, in step S22, the steering ECU 50 detects the actual pulling movement amounts i _FR and i _RR (or i) detected by the front and rear wheel movement amount sensors 29b and 29d (or 29a and 29c) opposite to the turning direction. _FL , _iRL ).

Subsequently, in step S23, the steering ECU 50 determines the target pulling movement amount i _FR *, i _RR * (or i _FL *, i _RL *) and the actual pulling movement amount i _FR , i _RR (or i _FL , i _RL ) based on the deviation Δi ((i _FR * −i _FR , i _RR * −i _RR ) or (i _FL * −i _FL , i _RL * −i _RL )), the retracting motors 33b and 33d ( Alternatively, a target current to be supplied to 33a, 33c) is set, and a control signal (for example, a PWM control signal) corresponding to the target current is output to the motor drive circuits 16b, 16d (or 16a, 16c). As a result, the amount of movement of the wheels W _FR , W _RR (or W _FL , W _RL ) with respect to the vehicle body is controlled to be the target amount of movement i _FR *, i _RR * (or i _FL *, i _RL *). Is done.

  The steering ECU 50 repeats such processing at a predetermined cycle until the turning of the vehicle is completed. This control cycle is set very short. Therefore, the steering operation and the pull-in operation of the wheel W are performed substantially simultaneously, and the pull-in resistance of the wheel W is reduced.

When the steering ECU 50 determines that the vehicle has turned 90 ° from the initial position (S19), the process proceeds to step S24. In step S24, the steering motors 12a, 12b, 12c, and 12d are driven to return the wheels W _FL , W _FR , W _RL , and W _RR to the neutral position, and the retracting motors 33b, 33d (or 33a, 33c) is driven to release the retracted state of the wheels _WFR , _WRR (or _WFL , _WRL ) and return to the normal position (the outermost position in the vehicle width direction).

In returning the wheels W _FR , W _RR (or W _FL , W _RL ) to the normal position, the actual pulling movement amounts i _FR , i _RR (or i) detected by the movement amount sensors 29b, 29d (or 29a, 29c). _A control signal is output to the motor drive circuits 16b and 16d (or 16a and 16c) so that _FL , _iRL ) becomes zero.

  This turning parking assistance control routine ends when the process of step S24 is completed. As in the first embodiment, the steering ECU 50 switches to the normal steering control mode when the turning parking support control routine ends.

  According to the second embodiment described above, in addition to the effects of the first embodiment, it is possible to prevent the wheels W from protruding outward from the vehicle body. First, the vehicle can be parked by entering the narrow L-shaped course that is the limit of the vehicle body size. In addition, since the wheel W can be positioned as far as possible in the vehicle width direction as long as it does not protrude from the outside of the vehicle body, stable turning can be performed.

  Also in the second embodiment, a modification similar to that in the first embodiment can be applied. For example, you may provide the alerting | reporting apparatus which announces that the turning parking assistance mode was complete | finished with respect to a driver | operator at the time of completion | finish of a turning parking assistance control routine. Further, when the steering handle 40 is suddenly rotated during execution of the turning parking support control routine, the turning parking support control routine may be terminated. Further, the left and right wheels may be applied to a vehicle equipped with a front and rear wheel independent steering system steering device that can not be independently steered and that can independently adjust only the steering angle of the front and rear wheels.

  The wheel retractor 30 in the second embodiment corresponds to the movement actuator in the present invention, the movement amount sensor 29 corresponds to the movement amount detection means in the present invention, and the steering ECU 50 and the motor drive circuit 16 in the present invention. It corresponds to a movement control means.

  As mentioned above, although the parking assistance apparatus for vehicles of this embodiment was demonstrated, this invention is not limited to the said embodiment, A various change is possible unless it deviates from the objective of this invention. For example, in the present embodiment, the target turning angle or the target pull-in movement amount with respect to the wheel rolling distance is set on the assumption that the shape of the vehicle is rectangular in plan view, but the roundness of the corner portion of the vehicle is taken into account. Then, the target value may be set. Moreover, although the example which puts a vehicle into a garage from the head part is shown in this embodiment, it can be garaged by retreating. In this case, for example, in the example shown in FIG. 3, the corner portion on the vehicle traveling direction side is the corner portion A on the vehicle rear end portion, and the corner portion on the opposite side of the vehicle is the corner portion B on the vehicle head portion.

  Moreover, although the electric motor is employ | adopted as an actuator which steers a wheel, it is also possible to employ | adopt other actuators, such as a solenoid.

  In the present embodiment, the turning direction is selected by the turning direction selection switch 25c. However, the turning direction instruction means may be configured to set a direction indicated by a winker (not shown) as the turning direction. In this case, a winker switch signal is input to the steering ECU 50, and the direction specified by the winker switch is set as the turning direction in the turning parking assistance mode.

  Further, in the present embodiment, the mode selection switch 25a for selecting the turning parking support mode and the start switch 25b for instructing the start of the turning parking support control are provided separately. Also good.

  Moreover, in 2nd Embodiment, although it comprised so that the ground contact center position of the wheel W might be moved to a vehicle width direction with respect to a vehicle body by the motor 33 for drawing in, it act | operates in conjunction with the change of a turning angle, for example. A mechanical link mechanism may be provided, and the ground contact center position of the wheel W may be moved by this link mechanism.

  In this embodiment, the present invention is applied to a four-wheel independent drive system vehicle. However, any four-wheel drive system that can apply rotational driving force to four wheels may be used. There is no.

1 is a schematic configuration diagram illustrating a vehicle parking assistance device according to a first embodiment of the present invention together with a four-wheel independent drive unit. It is a rear view explaining the outline of the steering mechanism concerning a 1st embodiment. It is explanatory drawing explaining the turning parking locus of the vehicle concerning 1st Embodiment. It is coordinate explanatory drawing used for calculation description of the target turning angle concerning 1st Embodiment. It is explanatory drawing showing each dimension of the vehicle concerning 1st Embodiment. It is a graph showing the movement locus | trajectory of the wheel ground contact center point concerning 1st Embodiment. It is a characteristic view showing the target turning angle corresponding to the rolling distance concerning 1st Embodiment. It is a flowchart showing the turning parking assistance control routine concerning 1st Embodiment. It is coordinate explanatory drawing used for calculation calculation of the target turning angle concerning the modification of 1st Embodiment. It is explanatory drawing explaining the protrusion state of a wheel. It is explanatory drawing showing the turning parking locus of a vehicle. It is a partial cross section rear view explaining the outline of the wheel drawing-in apparatus and steering mechanism concerning 2nd Embodiment. It is operation | movement explanatory drawing of the wheel drawing-in apparatus concerning 2nd Embodiment. It is a schematic block diagram showing the parking assistance apparatus for vehicles concerning 2nd Embodiment with the 4 wheel independent drive part. It is coordinate explanatory drawing used for calculation description of the target turning angle concerning 2nd Embodiment. It is explanatory drawing showing the relationship between the turning angle of the wheel concerning 2nd Embodiment, and the amount of pulling-in movement. It is a flowchart showing the turning parking assistance control routine concerning 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Steering mechanism, 11 ... Knuckle, 12a, 12b, 12c, 12d ... Steering motor, 13a, 13b, 13c, 13d ... Motor drive circuit, 14a, 14b, 14c, 14d ... Drive motor, 15a, 15b , 15c, 15d ... motor drive circuit, 16a, 16b, 16c, 16d ... motor drive circuit, 21a, 21b, 21c, 21d ... wheel steering angle sensor, 22a, 22b, 22c, 22d ... wheel speed sensor, 23 ... handle steering Angle sensor, 24 ... steering torque sensor, 25b ... start switch, 25a ... mode selection switch, 25c ... turning direction selection switch, 25 ... operation input unit, 26 ... shift position sensor, 27 ... accelerator pedal sensor, 28 ... brake pedal sensor , 29a, 29b, 29c, 29d ... movement amount sensor, 40 ... steering hand , 30 ... Wheel retractor, 31a ... Slide hole, 31 ... Slide holding housing, 32b ... Nut, 32 ... Ball screw mechanism, 33a, 33b, 33c, 33d ... Retraction motor, 50 ... Steering control unit, 100 ... Wheel drive control unit, A ... Advance direction side corner, B ... Non-advance direction side corner, C ... Vehicle, _DFL , _DFR , _DRL , _DRR ... Rolling distance, FR, FL, RR, RL ... wheel contact point, i _FL , i _FR , i _RL , i _RR ... pull-in travel, L1, L2 ... line, P ... parking lot, R ... passage, W _FL , W _FR , W _RL , W _RR ... wheel , Δ _FL , δ _FR , δ _RL , δ _RR ... actual turning angle, δ _FL *, δ _FR *, δ _RL *, δ _RR * ... target turning angle, θh ... steering wheel steering angle, ω _FL , ω _FR , Ω _RL , ω _RR … wheel speed.

Claims (8)

A steering actuator that independently adjusts the steering angles of at least the front and rear wheels;
A turning angle detection means for detecting the turning angle of each wheel;
Wheel rolling distance detecting means for detecting the rolling distance of each wheel,
Target turning angle setting means for setting the target turning angle of each wheel corresponding to the rolling distance of each wheel from the initial position of the vehicle;
Steering control means for driving and controlling the steering actuator so that the detected turning angle becomes the target turning angle, and for parking so that the vehicle turns along the target locus from the initial position. In a vehicle parking assistance device that supports driving operations,
The target turning angle setting means moves along a straight line extending in the vehicle width direction through the traveling direction side corner portion of the vehicle on the opposite side to the turning direction and passing through the traveling direction side corner portion at the initial position. Each corner corresponding to the rolling distance of each wheel is such that the opposite side corner of the vehicle on the opposite side of the vehicle moves along a straight line extending in the vehicle front-rear direction through the opposite corner in the initial position. A vehicle parking assistance apparatus, wherein a target turning angle of a wheel is set.   The target turning angle setting means assumes that the vehicle is rectangular in plan view, and the first vertex of the rectangle that is the corner in the traveling direction of the vehicle on the opposite side to the turning direction passes through the first vertex at the initial position. A straight line that moves along a straight line extending in the vehicle width direction and that extends in the vehicle front-rear direction through a second vertex of the rectangle that is the opposite corner of the vehicle on the opposite side of the turning direction and passes through the second vertex at the initial position. The vehicle parking assistance apparatus according to claim 1, wherein a target turning angle of each wheel corresponding to a rolling distance of each wheel is set so as to move along the wheel. The vehicle is provided with a turning instruction means for instructing a driver to start support for the parking driving operation,
The steering control means is configured such that the turning angle of each wheel becomes a target turning angle set by the target turning angle setting means when the start of parking operation support is instructed by the turning instruction means. The vehicle parking assistance apparatus according to claim 1, wherein drive control of the steering actuator is started as described above. Wheel position movement control means for moving the ground contact center position of the wheel in the vehicle width direction with respect to the vehicle body according to the turning angle of the wheel,
The said target turning angle setting means sets the said target turning angle in consideration of the part for the vehicle width direction movement of the grounding center position of the said wheel, The any one of Claim 1 thru | or 3 characterized by the above-mentioned. The parking assistance apparatus for vehicles as described.   The wheel position movement control means is configured so that the outer end of the wheel in the vehicle width direction is positioned on the same vertical plane extending in the vehicle front-rear direction regardless of the change in the turning angle, according to the turning angle of the wheel. 5. The vehicle parking assist apparatus according to claim 4, wherein the grounding center position is moved in the vehicle width direction with respect to the vehicle body. The wheel position movement control means includes:
A moving actuator that moves the ground contact center position of the wheel in the vehicle width direction with respect to the vehicle body;
A moving amount detecting means for detecting a moving amount of the ground contact center position of the wheel;
6. A movement control means for drivingly controlling the movement actuator so that the detected movement amount becomes a target movement amount set in accordance with a turning angle of a wheel. The parking assistance apparatus for vehicles as described.   The vehicle parking assistance apparatus according to any one of claims 1 to 6, which is applied to a vehicle including four-wheel independent driving means for independently rotating front, rear, left and right wheels.   When the target turning angle of the wheel exceeds the steerable range by the turning actuator, the turning angle obtained by reversing the target turning angle 180 ° to the left and right is set as the target turning angle, and the four wheels 8. The vehicle parking assistance apparatus according to claim 7, further comprising a reversing control unit that outputs a reversing command so as to reverse the rotational driving direction of the wheel with respect to the independent driving unit.

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