JP2009101774A - Steering device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make parallel parking easier by a simple constitution. <P>SOLUTION: A steering device distinguishes approach patterns of a vehicle on the basis of variations of distances a, b, c and d at approaching a parking space PS of a vehicle head VF, and calculates an approach angle θ toward the parking space PS by using a calculation formula matched to the distinguished approach pattern. Also, the device selects a determination condition for the propriety of parking to be set according to the approach pattern and determines whether the vehicle can park in parallel or not in the parking space PS following the determination condition. When the vehicle is determined so as to be possible to park in parallel, the vehicle is turned with the left front corner A of the vehicle head VF as a turning center. When the vehicle is determined so as to be impossible to park in parallel, a message of the restart of parking is announced to the driver. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a steering device having a function of supporting a parallel parking operation by controlling a turning angle of a wheel.

  Conventionally, for example, as proposed in Patent Document 1, the distance sensor mounted on the vehicle detects the size of the parking space and the distance to the vehicle relative to the parking space, and puts the vehicle in the parking space in the back There is known a device that determines whether or not it is possible and informs the driver of the determination result. In the device proposed in Patent Document 1, when a vehicle passes through a passage facing a parking space, a wall of the parking space is detected by a distance sensor, and the vehicle is stopped at a position past the parking space. Then, when the vehicle is moved backward from the stop position with the minimum turning radius, it is determined whether or not the parking space can be parked, and the determination result is displayed on the display unit.

In addition, a turning control technology for turning a vehicle in a narrow space by turning the front, rear, left and right wheels independently is also known. For example, in the device proposed in Patent Document 2, information on the surroundings of the vehicle is acquired, an optimal turning center is sequentially calculated so as to avoid surrounding obstacles, and the vehicle is turned at the calculated turning center. The steering angle of the front, rear, left and right wheels is controlled so that Parking driving operation is supported by automatic driving using such turning control technology.
JP-A-9-180100 JP2007-30808

  However, the device proposed in Patent Document 1 displays whether or not the driver can park when putting the vehicle in the garage in the back, and is not applicable to parallel parking. In particular, it is impossible to perform parallel parking in the parking space from the top of the vehicle. In addition, the device proposed in Patent Document 2 needs to change the turning center from moment to moment according to the surrounding conditions of the vehicle, and the calculation for sequentially calculating the turning center becomes complicated. Therefore, the calculation load of the microcomputer is large, and high specifications are required, leading to an increase in cost.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a steering device that is made to cope with the above-described problem and that can easily perform parallel parking from the front portion of a vehicle with a simple configuration.

  In order to achieve the above object, the present invention is characterized by a steering actuator that independently adjusts the steering angles of the front, rear, left, and right wheels, and a steering angle detection that detects the steering angles of the front, rear, left, and right wheels, respectively. And a steering control device that drives and controls the steering actuator so that the turning angle detected by the turning angle detection means becomes a target turning angle. When the selection operation means for selecting the support mode and the parallel parking support mode are selected, the target turning angle is set to the parallel parking steering so that the vehicle turns around the left and right sides of the vehicle head. There is a parking turning angle setting means for setting a corner.

  In the present invention, when the driver operates the selection operation means to select the parallel parking assistance mode, the parking turning angle setting means sets the target turning angle to the parallel parking turning angle. This parallel parking turning angle is a turning angle for turning the vehicle around a left and right one side end (one of the left and right ends and the turning direction side) of the vehicle head. The turning control means drives and controls the turning actuator so that the turning angle of each wheel detected by the turning angle detection means becomes the parallel parking turning angle.

  Therefore, the driver can turn the vehicle around the top corner by allowing the vehicle head to enter the parking space and operating the selection operation means to select the parallel parking support mode. It can be done easily. Further, since the turning center of the vehicle is set in advance, it is not necessary to sequentially calculate the turning center and the target turning angle during parking operation, and can be realized with a simple system.

  In addition, although it is preferable that one side end of the vehicle head part used as the turning center can be selected from right and left, it may be fixed to either one side so that selection is impossible.

  Another feature of the present invention is that, when the parallel parking support mode is selected, vehicle entry position detection means for detecting an entry position of the vehicle with respect to the parking space in a state where the vehicle head portion has entered the parking space; Based on the vehicle entry position and the vehicle body size with respect to the detected parking space, when the vehicle is turned from the vehicle entry position around the left and right sides of the vehicle head, the vehicles are parked in parallel in the parking space. A parking availability determining unit that determines whether or not it is possible, and a notification unit that notifies a driver when it is determined by the parking availability determination unit that parallel parking is not possible. When the parking possibility determining means determines that parallel parking is possible, the target turning angle is set to parallel parking so that the vehicle turns around the left and right side ends of the vehicle head. It is to set the steering angle.

  In the present invention, when the parallel parking support mode is selected, the vehicle entry position detection means detects the entry position of the vehicle with respect to the parking space in a state where the vehicle head has entered the parking space. For example, the driver thrusts the vehicle head into the parking space to stop the vehicle, and the vehicle position (vehicle head position) relative to the parking space in this state is detected. Then, when the parking permission / inhibition judging means turns the vehicle around the left and right side ends of the vehicle head from the approach position based on the approach position and the vehicle body size of the vehicle with respect to the parking space, the vehicle becomes the parking space. It is determined whether or not parallel parking is possible. In this case, since the vehicle entry position with respect to the parking space is detected in a state where the vehicle leading portion has entered the parking space, the position detection can be easily performed. Further, since the turning center of the vehicle is set at the left and right side ends of the vehicle head, the turning trajectory is constant when the vehicle is turned. Therefore, it becomes easy to determine whether the vehicle can be parked in parallel in the parking space.

  If it is determined that the vehicle can be parked in parallel in the parking space, the parking turning angle setting means sets the target turning angle to the parallel parking turning angle. Thus, the driver can easily perform parallel parking in the parking space without operating the steering wheel. On the other hand, when it is determined that the vehicle cannot be parked in parallel in the parking space, the notifying means notifies the driver to that effect. Therefore, unreasonable parallel parking can be prevented.

  Another feature of the present invention is that the vehicle entry position detection means includes means for detecting distances from separate positions at the left and right of the vehicle head portion to the parking space boundary in the vehicle front direction, and the parking availability determination means. Is to calculate the approach angle of the vehicle to the parking space based on the difference between the detected distances, and to determine whether or not the vehicle can be parked in parallel by taking into account the calculated approach angle of the vehicle. .

  In the present invention, the distances from the left and right separate positions of the vehicle head to the parking space boundary in the vehicle front direction (front in the vehicle front-rear direction) are detected. The parking space boundary refers to, for example, a wall that partitions the parking space or an obstacle such as another vehicle. When the vehicle enters the parking space obliquely with respect to the parallel parking direction (the longitudinal direction of the vehicle when parallel parking is performed), the distance to the parking space boundary in the vehicle front direction is different between the left and right detection positions. Therefore, the approach angle of the vehicle to the parking space can be estimated from this distance difference. Therefore, the parking permission / inhibition determining means calculates the approach angle of the vehicle from the difference between the left and right distances, and determines whether or not the vehicle can be parked in parallel by using this approach angle (used as one of the determination elements). . As a result, the determination accuracy of the parking availability determination unit is increased.

  Another feature of the present invention is that the vehicle approach position detecting means includes a left front distance from the left end of the vehicle head to the parking space boundary in the front direction of the vehicle and a right end of the vehicle head to the parking space boundary in the direction of the front of the vehicle. Distance detection to detect the right front distance of the vehicle, the left side distance from the left end of the vehicle head to the left parking space boundary, and the right side distance from the right end of the vehicle head to the right parking space boundary And a means for determining whether or not the parking is possible when the vehicle is turned around the left and right ends of the vehicle head based on the distance detected by the distance detection means and the vehicle body size. Is to determine whether or not parallel parking is possible.

  In the present invention, distance detection means is provided as vehicle entry position detection means. The distance detection means is the distance from the vehicle head to the parking space boundary in the front direction (front in the vehicle longitudinal direction), left side direction (left direction in the vehicle width direction), and right side direction (right direction in the vehicle width direction). Is detected. As for the front direction, the distance is detected from the left end and the right end of the vehicle head. Thereby, the approach position of the head part of the vehicle with respect to the parking space divided in the U shape by the parking space boundary can be detected satisfactorily. In this case, the approach angle with respect to the parallel parking direction of the vehicle can also be calculated based on each detection distance. As a result, the determination accuracy by the parking availability determination means is improved.

  Another feature of the present invention is that the parking permission / inhibition determining means is configured such that the vehicle head relative to the parking space is based on a change in each distance detected by the distance detecting means when the vehicle head enters the parking space. An approach pattern discriminating means for discriminating an approach pattern of the vehicle, an approach angle calculating means for calculating an approach angle to the parking space of the vehicle by a calculation formula corresponding to the discriminated approach pattern, and the discriminated approach pattern And a determination condition selection means for selecting a parking permission / inhibition determination condition including the approach angle.

  In this invention, an approach pattern discriminating means discriminates an approach pattern of the vehicle head portion with respect to the parking space based on a change in each detection distance when the vehicle head portion enters the parking space. The change in the detection distance can be represented by a change amount of the detection distance with respect to the approach distance to the parking space of the vehicle.

  For example, when the vehicle head portion enters a parking space where the parking space boundary is formed in a U-shape, depending on the vehicle entry angle, the right front distance measured from the right end of the vehicle head portion in the vehicle front direction, In some cases, the left front distance measured in the vehicle front direction from the left end of the front of the vehicle is not a measurement of the distance to the same linear parking space boundary. In such a case, the vehicle approach angle cannot be calculated from the difference between the right front distance and the left front distance. Therefore, the approach pattern at the head of the vehicle is determined by detecting changes in the measurement distances on the front and side surfaces of the left and right sides of the vehicle.

  When the approach pattern at the head of the vehicle is determined, the approach angle calculation means calculates the approach angle to the parking space of the vehicle using a calculation formula corresponding to the determined approach pattern. Then, the determination condition selection means selects a parking availability determination condition set according to the determined approach pattern. This parking permission / inhibition determination condition includes an approach angle of the vehicle. As a result, the accuracy of determining whether to park is further improved.

  Another feature of the present invention resides in that the informing means informs the driver of a request for re-insertion into the parking space at the head of the vehicle when it is determined that the parallel parking is not possible by the parking possibility determining means. . In this case, based on the requirement which did not satisfy | fill the parking availability determination conditions, it is good to alert | report the change method of the approach position to the parking space of a vehicle head part with respect to a driver | operator.

  In this invention, when it is determined that the vehicles cannot be parked in parallel in the parking space, the notification means notifies the driver of the request for re-insertion into the parking space at the head of the vehicle. At this time, the driver is informed of a method of changing the approach position to the parking space at the head of the vehicle based on the requirements that did not satisfy the parking availability determination condition. Therefore, the driver can reinsert the vehicle head at the appropriate position of the parking space according to this notification. As a result, parallel parking is possible.

  Another feature of the present invention resides in that the parking permission / inhibition determining means is determined in consideration of a space for getting off the passenger.

  In this invention, when determining whether or not the vehicle can be parked in parallel in the parking space, a more appropriate determination can be obtained because the determination is made taking into account the space for getting off the passenger (used as one of the determination requirements). It is done.

  Hereinafter, a steering apparatus according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram illustrating the steering device according to the first 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 steering device of the present embodiment is mounted includes a wheel drive actuator (for example, the drive motor 14) that rotationally drives each wheel W, and a wheel drive control unit that independently drives and controls each wheel drive actuator. 4 wheel independent drive means having (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, the steering wheel steering angle sensor 23, the operation input unit 25, and the distance sensors 24a, 24b, 24c, and 24d are connected. Further, the steering ECU 50 has motor drive circuits 13a, 13b, 13c, and 13d and an audio announcement device 16 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 tire outer peripheral 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 employ a configuration that detects and calculates the wheel rolling distance from the rotation angle and the tire outer peripheral 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 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 parallel parking support mode selection switch 25a (hereinafter referred to as a support mode selection switch 25a), a turning direction selection switch 25b, A boarding / alighting space selection switch 25c. The support mode selection switch 25a is an operation switch for selecting the parallel parking support mode by operating when the driver wants to obtain parallel parking support described later. When the driver is turned on, the support mode selection switch 25a is operated with respect to the steering ECU 50. To output a parallel parking assistance mode selection signal. The support mode selection switch 25a corresponds to the selection operation means of the present invention.

  The turning direction selection switch 25b is an operation switch for selecting a turning direction at the time of parallel parking assistance, and outputs a turning direction selection signal to the steering ECU 50. The boarding / alighting space selection switch 25c is an operation switch for setting a boarding / alighting space that is at least secured when parallel parking is performed by parallel parking support control.

  The operation input unit 25 may be provided exclusively, but an information terminal device can also be used. For example, a touch panel display of a navigation device can be used also. In this case, the mode selection screen for selecting the parallel parking assistance mode, the turning direction selection screen for selecting the turning direction, and the boarding / exiting space selection screen for selecting the boarding / exiting space are displayed on the touch panel display. Each screen may be configured such that the selection button can be touch-operated on the screen.

  The distance sensors 24a, 24b, 24c, and 24d correspond to the distance detecting means of the present invention, and measure the distance from the vehicle body to the obstacle. As the distance sensors 24a, 24b, 24c, and 24d, for example, a clearance sonar can be used. The clearance sonar uses ultrasonic waves, and includes a transmitter that transmits ultrasonic waves and a receiver that receives reflected waves. Based on the detection state of the reflected waves in the receiver, the clearance sonar is between the obstacle and the clearance sonar. The distance is detected.

  The distance sensors 24a and 24b are provided at the left end (hereinafter referred to as the left front corner) of the vehicle leading portion, and the distance sensors 24c and 24d are provided at the right end (hereinafter referred to as the right front corner) of the vehicle leading portion. The distance sensor 24a detects the distance from the left front corner to an obstacle existing in the vehicle front direction (front in the vehicle front-rear direction). The distance sensor 24b detects the distance from the left front corner to the obstacle present in the left direction of the vehicle (left direction in the vehicle width direction). The distance sensor 24c detects the distance from the right front corner to the obstacle existing in the vehicle front direction. The distance sensor 24b detects the distance from the right front corner to the obstacle present in the vehicle right direction. The distance information detected by the distance sensors 24a, 24b, 24c, and 24d is output to the steering ECU 50. Hereinafter, the distance to the obstacle detected by the distance sensor 24a is the left front distance a, the distance to the obstacle detected by the distance sensor 24b is the left lateral distance b, and the distance to the obstacle detected by the distance sensor 24c is The distance to the obstacle detected by the right front distance c and the distance sensor 24d is called a right lateral distance d.

  The voice announcement device 16 notifies the driver of a plurality of types of messages for parking assistance by voice, and constitutes part of the notification means of the present invention. The voice announcement device 16 includes a storage unit (not shown) that stores voice data for each message, and a voice playback unit that plays back a message specified by the command when a voice generation command is input from the steering ECU 50. (Not shown). Although this voice announcement device 16 may be provided exclusively, for example, the voice announcement function of the navigation device may also be used.

  The wheel driving ECU 100 includes a microcomputer including a CPU, a ROM, a RAM, and the like as a main part, and an accelerator pedal sensor 27, a brake pedal sensor 28, and a shift position sensor 26 are connected to an input interface. . Further, the steering ECU 50 has motor drive circuits 15a, 15b, 15c and 15d connected to the 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 shift position sensor 26 detects the position of a shift lever (not shown) and outputs a signal representing the shift position to the wheel driving ECU 100. The shift position signal detected by the shift position sensor 26 is also output to the steering ECU 50.

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 steering ECU 50 has a parallel parking support function, which will be described later, in addition to a normal steering control function. The steering ECU 50 performs normal steering control when the normal mode is selected by the selection operation of the operation input unit 25, and performs parallel parking support control when the parallel parking support mode is selected. Therefore, the steering ECU 50 separately stores a control program for performing normal steering control and a control program for performing parallel parking support control 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 15a, 15b, 15c, and 15d. 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, parallel parking support control will be described. FIG. 3 shows a vehicle V and a parking space PS where the driver wants to perform parallel parking. This parking space PS is an area surrounded by a wall surface (parking space boundary) in a U-shape and an open surface is adjacent to the passage R. Hereinafter, in the parking space PS, the right wall in the drawing is called the right parking wall WR, the left wall in the drawing is called the left parking wall WL, and the wall between the right parking wall WR and the left parking wall WL is called the front parking wall WC. When the three parking walls WR, WL, and WC are not specified, they are simply referred to as parking walls W. Each parking wall WR, WL, WC is a flat surface, and the right parking wall WR and the left parking wall WL are orthogonal to the front parking wall WC. Moreover, the planar view shape of the vehicle V is assumed to be a rectangle.

  In this parking space PS, the distance from the passage R to the front parking wall WC is shorter than the distance between the walls WR and WL facing left and right. Therefore, the driver parks the vehicle V in accordance with the front-rear direction of the vehicle V in the direction in which the left and right walls WR and WL face each other (the left-right direction in FIG. 3). That is, parallel parking is performed.

  Here, an overview of the overall flow performed by the driver and the steering ECU 50 will be described with reference to the flowchart of FIG. In this flowchart, the driver performs the processes that are filled and displayed.

  The driver turns on the support mode selection switch 25a in advance before the vehicle V enters the parking space PS (S11). Thereby, the ECU 50 for steering starts distance measurement with the obstacle by the distance sensors 24a, 24b, 24c, and 24d (S12). The driver checks the direction in which the vehicle V is turned before turning on the support mode selection switch 25a. If the direction is different from the current setting, the driver selects the turning direction using the turning direction selection switch 25b. Set.

  Subsequently, the driver causes the vehicle head portion VF to enter the parking space PS and stops the vehicle V (S13). At this time, the driver moves the vehicle V forward to a position where the vehicle head portion VF enters the parking space PS without turning the vehicle V. The steering ECU 50 ends the distance measurement in the vehicle front direction and the vehicle left-right direction by the distance sensors 24a, 24b, 24c, 24d (S14). In this case, the steering ECU 50 repeats the distance measurement at a predetermined short period from when the support mode selection switch 25a is turned on until the vehicle V enters the parking space PS and stops.

Subsequently, the steering ECU 50 determines whether or not the vehicle V can be parked in parallel in the parking space PS based on the measurement results measured by the distance sensors 24a, 24b, 24c, and 24d (S15). When it is determined that parking is possible (S16: YES), the voice announcement device 16 announces to the driver that the turning parking operation of the vehicle V is started (S17) and the four wheels W _FL , W _FR , W _RL and W _RR are steered to the parallel parking turning angle (S18). This parallel parking turning angle is an angle set so that the vehicle V turns around the left front corner A (right front corner B in the case of right turn), and is stored in advance in the ROM of the steering ECU 50. Has been. The driver releases the brake stepping force by this announcement and advances the vehicle V in the creep state (S19). As a result, the vehicle V turns around the left front corner A without operating the steering wheel.

  When the right side surface of the vehicle V is parallel to the front parking wall WC of the parking space PS, the voice announcement device 16 announces to the driver that the turn is over (S20). The driver increases the brake depression force by this announcement and stops the vehicle (S21). Thus, parallel parking is completed. FIG. 3 shows a turning locus of the vehicle V at the time of parallel parking with a broken line.

  On the other hand, if it is determined that parking is not possible (S16: NO), the steering ECU 50 instructs the driver to reinsert the vehicle V into the parking space PS by the voice announcement device 16 and performs the reinsertion. Is instructed how to move the vehicle V (S22). In accordance with this announcement, the driver takes the vehicle V out of the parking space PS and enters it again into the parking space PS (S23). Then, the driver operates the support mode selection switch 25a again (S11). Thereby, the process from step S12 mentioned above is restarted.

Therefore, the vehicle head portion VF is entered into the parking space PS to determine whether or not parallel parking can be performed in the parking space PS. When it is determined that parallel parking is possible, the four wheels W _FL and W are automatically selected. The steering angles of _FR , W _RL and W _RR are set as the parallel parking turning angle. Accordingly, the driver can park the vehicle V in the parking space PS without operating the steering wheel. Further, when the approach position of the vehicle head portion VF is inappropriate, an instruction for reinserting the vehicle V and its method are announced, so that the driver can reinsert the steering wheel without hesitation.

  Next, the parallel parking support control process performed on the steering ECU 50 side will be described. FIG. 5 is a flowchart showing a parallel parking support control routine performed on the steering ECU 50 side. This parallel parking support control routine is stored as a control program in the ROM of the steering ECU 50, and is repeatedly executed when an ignition switch (not shown) is in an ON state. This parallel parking support control routine explains in detail the processing performed by the steering ECU 50 in the flowchart of FIG. 4, and even if the processing overlaps with the processing in the flowchart of FIG. 4, another step number is assigned. is doing.

  When the parallel parking assistance control routine is activated, the steering ECU 50 reads the state of the assistance mode selection switch 25a in step S31 and determines whether or not it is turned on. This determination is repeated at a predetermined cycle until the support mode selection switch 25a is turned on. When the driver turns on the support mode selection switch 25a, the steering ECU 50 advances the process to step S32.

  In step S32, the steering ECU 50 performs distance measurement using the distance sensors 24a, 24b, 24c, and 24d. In this case, the distance sensor 24a measures the left front distance a from the left front corner A of the vehicle V to the obstacle existing in the front direction of the vehicle, and the distance sensor 24b measures the obstacle present in the left direction of the vehicle V from the left front corner A. The left lateral distance b is measured, the distance sensor 24c measures the right front distance c from the right front corner B of the vehicle V to the obstacle existing in the front direction of the vehicle, and the distance sensor 24d measures the vehicle from the right front corner B of the vehicle V. The right lateral distance d to the obstacle present in the right direction is measured.

  Subsequently, the steering ECU 50 determines whether or not the vehicle V has stopped in step S33. In this case, it is determined whether or not the vehicle V is in a stopped state from the forward traveling state. In other words, the determination process in step S33 is to determine whether or not the driver has advanced and stopped the vehicle V until the vehicle head portion VF enters the parking space PS after the driver turns on the support mode selection switch 25a. is there. In step S33, the steering ECU 50 reads the wheel speed ω detected by the wheel speed sensor 22 (any one of 22a, 22b, 22c, and 22d), for example, and the wheel speed ω is once increased from zero. After the increase, it is decreased again to zero, and it is determined whether or not zero (stopped state) is maintained for the reference time. The process in step S33 may be determined by reading a vehicle speed signal detected by a vehicle speed sensor (not shown) instead of detecting the wheel speed.

  The steering ECU 50 repeats the process of step S32 while the stop of the vehicle V is not confirmed. At this time, the measurement data of the left front distance a, the left lateral distance b, the right front distance c, and the right lateral distance d measured in step S32 is sequentially stored in a memory such as a RAM, and each measurement distance a, b, A history of c and d is obtained.

  When the stop of the vehicle V is confirmed in step S33, the steering ECU 50 determines the entry pattern of the vehicle V into the parking space PS in step S34. This approach pattern is determined in order to set a determination condition for determining whether or not the vehicle V can be parked in the parking space PS.

  Here, the approach pattern will be described. In this embodiment, the approach pattern with respect to the parking space PS of the vehicle V is classified into four types. 6 represents a first approach pattern, FIG. 7 represents a second approach pattern, FIG. 8 represents a third approach pattern, and FIG. 9 represents a fourth approach pattern. 6 to 9, (A) represents changes in the left front distance a, the left lateral distance b, the right front distance c, and the right lateral distance d detected until the vehicle V stops, with respect to the vehicle approach distance. ) Represents an approach stop position of the vehicle V with respect to the parking space PS. In addition, the pattern demonstrated here is an approach pattern when turning the vehicle V to the left and performing parallel parking.

  As shown in FIG. 6, the first approach pattern is a pattern in which the vehicle V is entered in a direction perpendicular to the parallel parking direction (the direction in which the left and right parking walls WR and WL face each other). In the first pattern, the left front distance a and the right front distance c are equal, and the reduction rate (the reduction amount of the measurement distance that changes with respect to the vehicle approach distance) is constant. Further, the left lateral distance b and the right lateral distance d are kept constant regardless of the vehicle approach distance.

In this first approach pattern, a determination condition formula for determining whether the vehicle V can be parked in parallel in the parking space PS (hereinafter referred to as a first pattern parking permission determination condition formula) can be determined as follows. . That is, when the following three expressions are satisfied, it can be determined that the vehicle V can be parked in parallel in the parking space PS. Here, Lb is the full length of the vehicle, Lt is the full width of the vehicle, α1 is a margin for the left parking wall WL, α2 is a margin for the front parking wall WC, and α3 is a margin for the right parking wall WR. Α2 is necessary to secure a space for the driver to get on and off, and is a value set by a boarding space selection switch 25c provided in the operation input unit 25.
<First pattern parking availability determination conditional expression>

  The second to fourth entry patterns are patterns in which the vehicle V is made to enter obliquely with respect to the front parking wall WC. In the second approach pattern, as shown in FIG. 7B, while the vehicle V is entering and moving into the parking space PS, the distance a to the front parking wall WC by the distance sensor 24a and the distance sensor 24c. c is measured, the distance b from the left parking wall WL is measured by the distance sensor 24b, and the distance d from the right parking wall WR is measured by the distance sensor 24d.

  In the third approach pattern, as shown in FIG. 8B, while the vehicle V is entering and moving into the parking space PS, the distance a to the front parking wall WC by the distance sensor 24a and the distance sensor 24c, c is the same as the second approach pattern in that the distance sensor 24b measures the distance b from the left parking wall WL by the distance sensor 24b, but the distance measurement object by the distance sensor 24d is moving from the right parking wall WR during the approach movement. It differs from the second approach pattern in that it changes to the front parking wall WC.

  In the fourth approach pattern, as shown in FIG. 9B, while the vehicle V is entering and moving into the parking space PS, the distance a to the left parking wall WL by the distance sensor 24a and the distance sensor 24b, b is measured, the distance sensor 24c measures the distance c from the front parking wall WC, the distance sensor 24d measures the distance d from the right parking wall WR at the beginning of the approach, and then the distance d from the front parking wall WC. The Therefore, it differs from the third approach pattern in that the distance sensor 24a measures the distance a from the left parking wall WL.

  In the second approach pattern, as shown in FIG. 7A, the left front distance a is larger than the right front distance c (a> c), and the rate of decrease of the left front distance a and the right front distance c (relative to the vehicle approach distance). The amount of change in the measured distance is the same constant value. Moreover, the decreasing rate of the left lateral distance b is constant. Further, the increase rate of the right lateral distance d (the increase amount of the measurement distance that changes with respect to the vehicle approach distance) is constant.

In this second approach pattern, the difference between the left front distance a and the right front distance c is the vehicle V entry angle θ (the angle between the vehicle V width direction and the parallel parking direction (formation direction of the front parking wall WC)). Can be calculated by the following calculation formula.
tan θ = (ac) / Lt

In the second approach pattern, a determination condition expression for determining whether the vehicle V can be parked in parallel in the parking space PS (hereinafter referred to as a second pattern parking permission determination condition expression) is determined as follows. it can. That is, when the following three expressions are satisfied, it can be determined that the vehicle V can be parked in parallel in the parking space PS.
<2nd pattern parking availability determination conditional expression>

  In the third approach pattern, as shown in FIG. 8A, the left front distance a is larger than the right front distance c (a> c), and the reduction rates of the left front distance a and the right front distance c are the same constant value. Moreover, the decreasing rate of the left lateral distance b is constant. On the other hand, the right lateral distance d increases when the distance d to the right parking wall WR is measured, and starts to decrease when the distance measurement target is switched to the front parking wall WC.

  In the figure, b1 is the distance from the left parking wall WL first detected by the distance sensor 24b when the vehicle head portion VF enters the parking space PS, and b2 is the left parking when the vehicle V stops. The distance from the wall WL. D0 is a distance detected by the distance sensor 24d when the distance measurement target of the distance sensor 24d is switched from the right parking wall WR to the front parking wall WC while the vehicle V is moving. Further, δ12 represents an approach distance until the vehicle V stops after the distance b1 is detected by the distance sensor 24b, that is, an approach distance until the distance b2 is detected. This δ12 is, for example, the difference between the measurement distance a1 of the distance sensor 24a when the distance b1 is detected by the distance sensor 24b and the measurement distance a2 of the distance sensor 24a when the distance b2 is detected by the distance sensor 24b. Can be sought.

In this third approach pattern, the approach angle θ of the vehicle V can be calculated by the following calculation formula.
tan θ = (ac) / Lt or tan θ = (b1−b2) / δ12

In the third approach pattern, a determination condition formula for determining whether the vehicle V can be parked in parallel in the parking space PS (hereinafter referred to as a third pattern parking permission determination condition formula) is determined as follows. it can. That is, when the following three expressions are satisfied, it can be determined that the vehicle V can be parked in parallel in the parking space PS.
<Third pattern parking availability determination conditional expression>

  In the fourth approach pattern, as shown in FIG. 9A, the left front distance a is larger than the right front distance c (a> c), and the decrease rates of the left front distance a and the right front distance c are the same constant value. Moreover, the decreasing rate of the left lateral distance b is constant. On the other hand, the right lateral distance d increases when the distance d to the right parking wall WR is measured, and starts to decrease when the distance measurement target is switched to the front parking wall WC.

  This fourth approach pattern differs from the third approach pattern in that the ratio (a / b) between the distance a and the distance b does not change with the approach movement of the vehicle V. In the fourth approach pattern, both the distance sensor 24a and the distance sensor 24b detect the distance to the left parking wall WL. For this reason, when attention is paid to a triangle connecting the measurement point PL1 of the left parking wall WL by the distance sensor 24a, the measurement point PL2 of the left parking wall WL by the distance sensor 24b, and the left front corner A, this triangle is Maintains a similar relationship, although the size varies with the amount of entry. Therefore, the ratio (a / b) between the distance a and the distance b does not change and is constant.

  On the other hand, in the third approach pattern, the ratio (a / b) between the distance a and the distance b changes with the approach movement of the vehicle V. In the third approach pattern, the distance sensor 24a detects the distance to the front parking wall WC, and the distance sensor 24b detects the distance to the left parking wall WL. For this reason, measurement point PC1 of front parking wall WC by distance sensor 24a, intersection point PCL of front parking wall WC and left parking wall WL, measurement point PL2 of left parking wall WL by distance sensor 24b, and front left corner A Focusing on the quadrilateral connecting the two, the quadrilateral does not have a similar relationship because its shape changes according to the amount of vehicle V entering.

  Therefore, the third approach pattern and the fourth approach pattern can be discriminated by detecting the change state between the distance a and the distance b and detecting the change in the ratio (a / b) between them.

In the fourth approach pattern, the approach angle θ of the vehicle V can be calculated by the following calculation formula.
tan θ = (b1−b2) / δ12

In the fourth approach pattern, a determination condition expression for determining whether the vehicle V can be parked in parallel in the parking space PS (hereinafter referred to as a fourth pattern parking permission determination condition expression) is determined as follows. it can. That is, when the following three expressions are satisfied, it can be determined that the vehicle V can be parked in parallel in the parking space PS.
<Fourth pattern parking availability determination conditional expression>

  Returning to the description of the parallel parking support control routine of FIG. In step S34, the entry pattern of the vehicle V into the parking space PS is determined. As described above, the approach pattern is determined based on the distances a, b, c, d repeatedly detected by the distance sensors 24a, 24b, 24c, 24d when the vehicle V enters the parking space PS. FIG. 10 is a flowchart showing the approach pattern determination process in step S34 as a subroutine.

When this approach pattern determination process is started, the steering ECU 50 determines whether or not all the following first determination conditions are satisfied in step S341. Note that the rate of change (decrease rate, increase rate) of the distances a, b, c, and d is calculated based on the history of measurement data stored in step S32.
1. The distance a is equal to the distance c.
2. The decreasing rate of the distance a and the distance c is constant.
3. The distance b and the distance d are constant.

When the steering ECU 50 satisfies the first determination condition, the steering ECU 50 determines that the first approach pattern is set in step S342. On the other hand, if it is determined in step S341 that the first determination condition is not satisfied (S341: NO), it is determined in step S343 whether or not all the following second determination conditions are satisfied.
1. The distance a is larger than the distance c.
2. The decreasing rate of the distance a and the distance c is constant and the same.
3. The decreasing rate of the distance b is constant.
4). The increasing rate of the distance d is constant.

When the second determination condition is satisfied, the steering ECU 50 determines that the second approach pattern is in step S344. On the other hand, if it is determined in step S343 that the second determination condition is not satisfied (S343: NO), it is determined in step S345 whether or not all the following third determination conditions are satisfied.
1. The distance a is larger than the distance c.
2. The decreasing rate of the distance a and the distance c is constant and the same.
3. The decreasing rate of the distance b is constant.
4). The distance d starts to decrease after increasing.

  When the steering ECU 50 satisfies the third determination condition, subsequently, in step S346, whether or not the ratio (a / b) between the distance a and the distance b is constant as the fourth determination condition. Judging. If the fourth determination condition is satisfied (S346: YES), it is determined in step S347 that it is the fourth approach pattern. On the other hand, if it is determined in step S346 that the fourth determination condition is not satisfied (S346: NO), it is determined in step S348 that it is the third approach pattern.

  Further, when the third determination condition is not satisfied in step S345 (S345: NO), it is determined in step S349 that the approach pattern is unknown. When the steering ECU 50 completes the approach pattern determination process, the steering ECU 50 exits the approach pattern determination subroutine and proceeds to step S35 of the main routine shown in FIG. If it is determined in step S349 that the approach pattern is unknown, parallel parking support is not possible, and the process proceeds to step S44 described later.

  In step S35, the steering ECU 50 sets a calculation formula for the vehicle approach angle θ according to the approach pattern, and calculates the vehicle approach angle θ in step S36. The calculation formula of the vehicle approach angle θ corresponding to this approach pattern is as described above. Further, in the case of the first approach pattern, the calculation of the vehicle approach angle θ is unnecessary and is not performed.

  Subsequently, in step S37, the steering ECU 50 sets a parking availability determination conditional expression corresponding to the entry pattern. That is, the parking condition determination condition formula corresponding to the approach pattern is selected from the above-described first to fourth pattern parking condition determination conditions. Next, in step S38, the steering ECU 50 substitutes variables (measurement distance, vehicle approach angle, margin allowance α2) into the selected parking availability determination conditional expression, and calculates the left side and the right side of each expression.

  Subsequently, in step S39, the steering ECU 50 determines that the vehicle V can be parked in parallel in the parking space PS and satisfies the inequality sign in the parking qualification condition expression when the inequality sign in the parking condition determination condition formula is satisfied. If not, it is determined that the vehicle V cannot be parked in parallel in the parking space PS. The allowance α2 is obtained by reading the set value set by the boarding / alighting space selection switch 25c.

  When the turning ECU 50 determines in step S39 that parallel parking is possible, the turning ECU 50 outputs a turn start announcement command signal to the voice announcement device 16 in step S40. On the basis of this command signal, the voice announcement device 16 reads the turning start announcement data from the voice data stored in advance, and utters a message that the turning can be started. For example, a message such as “You can turn parking. Please release the brake.” Is announced to the driver.

The turning ECU 50 proceeds to step S41 simultaneously with the start of the announcement in step S40, and the turning angles of the wheels W _FL , W _FR , W _RL , W _RR are the parallel parking turning angles δ _FLP , δ _FRP , _Steer so that δ _RLP and δ _RRP .

The parallel parking turning angles δ _FLP , δ _FRP , δ _RLP , and δ _RRP are target turning angles for turning the vehicle V around the left and right ends of the front of the vehicle, and are previously stored in the ROM of the steering ECU 50. Is stored within. In this embodiment, an example in which the vehicle V is turned around the left front corner A is described.

Parallel parking steering angle [delta] _FLP of the left front wheel W _FL, as shown by a broken line in FIG. 3, is set to an angle which is a left front corner A and the left front wheel W _FL orthogonal direction to a straight line connecting the grounding center , parallel parking steering angle δ _FRP of the right front wheel W _FR is set at an angle to the left front corner a and the right front wheel W _FR perpendicular to the direction in a straight line connecting the ground center of, parallel parking of the left rear wheel W _RL The turning angle δ _RLP is set to an angle that is perpendicular to a straight line connecting the left front corner A and the ground center of the left rear wheel W _RL , and the parallel parking turning angle δ _RRP of the right rear wheel W _RR is: The angle is set to an angle that is orthogonal to a straight line connecting the left front corner A and the ground contact center of the right rear wheel _WRR .

In step S41, the turning ECU 50 reads the actual turning angles δ _FL , δ _FR , δ _RL , δ _RR detected by the wheel steering angle sensors 21a, 21b, 21c, 21d, and this actual turning angle δ _FL. , Δ _FR , δ _RL , δ _RR and the deviation of the parallel parking turning angle δ _FLP , δ _FRP , δ _RLP , δ _RRP (δ _FLP −δ _FL , δ _FRP −δ _FR , δ _RLP −δ _RL , δ _RRP steering motor 12a corresponding to -δ _RR), 12b, 12c, and sets a target current to be energized 12d, the control signals (e.g., PWM control signal) to the motor driving circuit 13a corresponding to the target current, 13b, 13c , 13d. As a result, the steering motors 12a, 12b, 12c, and 12d are driven, and the steering angles of the wheels W _FL , W _FR , W _RL , and W _RR are the parallel parking steering angles δ _FLP , δ _FRP , δ _RLP , δ It is controlled to be _RRP .

  The driver advances the vehicle V in the creep state by relaxing the brake stepping force by the announcement uttered in step S40. As a result, the vehicle V turns around the left front corner A without operating the steering wheel.

In step S42, the turning ECU 50 detects the rolling distance D _RL of the left rear wheel W _RL and determines whether the detected rolling distance D _RL has reached the turning end determination distance D0. The rolling distance D _RL of the left rear wheel W _RL reads the wheel speed ω _RL of the wheel W _RL detected by the wheel speed sensor 22c, and the rotation speed ω _RL and the tire outer diameter of the wheel W (to the steering ECU 50). Is stored). Further, the turning end determination distance D0 is calculated by the following equation.
D0 = L _RL · (π / 2−θ)

Here, L _RL is a planar distance from the turning center of vehicle V (left front corner A) to the ground center point of left rear wheel W _RL . (Π / 2−θ) is an angle necessary for turning the vehicle V to the parallel parking position. Therefore, when the rolling distance D _RL reaches the turning end determination distance D0, the vehicle V has turned to the parallel parking position.

In the present embodiment, the turning end timing is determined based on the rolling distance D _RL of the left rear wheel W _RL , but may be based on the rolling distance of other wheels W.

The turning ECU 50 continues the turning angle control in step S41 until the rolling distance D _RL reaches the turning end determination distance D0. When it is determined that the rolling distance D _RL has reached the turning end determination distance D0 (S42: YES), a turning end announcement command signal is output to the voice announcement device 16 in step S43. Based on this command signal, the voice announcement device 16 reads turn completion announcement data from previously stored voice data and utters a message to the effect that the turn is finished. For example, a message such as “End of turn. Please stop the vehicle” is announced to the driver. With this announcement, the driver increases the brake stepping force and stops the vehicle V.

  When the steering ECU 50 makes an announcement in step S43, the parallel parking assist control routine is temporarily terminated. At this time, the support mode selection switch 25a is reset to the off state.

  On the other hand, if it is determined in step S39 that parallel parking is impossible, the process of step S44 is performed. In step S44, the steering ECU 50 outputs an unparkable announcement command signal and an unparkable cause signal to the voice announcement device 16. In step S39, the steering ECU 50 determines whether or not the parking possibility determination conditional expression is satisfied, and outputs a parking impossibility cause signal corresponding to an item that does not satisfy the parking permission determination conditional expression at that time. . For example, if it is determined that the first condition (first expression) in the parking availability determination conditional expression is not satisfied, a parking impossibility cause signal indicating insufficient separation from the left parking wall WL is output to the voice announcement device 16. . In addition, when it is determined that the second condition (second expression) in the parking availability determination conditional expression is not satisfied, a parking impossibility cause signal indicating insufficient separation from the front parking wall WC is output to the voice announcement device 16. . Further, when it is determined that the third condition (third expression) in the parking availability determination conditional expression is not satisfied, a parking impossibility cause signal indicating insufficient separation from the right parking wall WR is output to the voice announcement device 16. .

  Thereby, the voice announcement device 16 reads out the data for reinsertion movement advice according to the cause of the inability to park from the voice data stored in advance, and utters the message specified in the data. For example, if the cause of the inability to park is insufficiently separated from the left parking wall WL, “You are too far to the left. Please try again to enter the right.” If the distance is insufficient, “You are too close to the right. Please try again by approaching to the left.” If the cause of the inability to park is insufficient for the separation from the front parking wall WC, Say a message about how to change the approach position. In addition, if a plurality of causes of parking failure are detected, a message that combines them is uttered.

  If the approach pattern of the vehicle V cannot be determined in step S34, the steering ECU 50 outputs only the unparkable announcement command signal to the voice announcement device 16 in step S44. As a result, the voice announcement device 16 utters a message such as "Please turn it on again."

  Thus, the steering ECU 50 informs the driver of the message including the travel advice if the parallel parking is impossible, and once ends the parallel parking support control routine. The parallel parking support control routine is repeated at a predetermined short cycle. Therefore, the parallel parking assistance control routine is immediately resumed, and the confirmation process of the assistance mode selection switch 25a in step S31 described above is started. When the driver moves the vehicle V according to the advice from the voice announcement device 16 and turns on the support mode selection switch 25a again, distance measurement is started in step S32, and the above-described processing is performed thereafter.

  According to the steering device of the present embodiment described above, the vehicle V is moved to the front left corner A by simply pushing the vehicle head portion VF into the parking space PS and operating the support mode selection switch 25a to select the parallel parking support mode. (Or right front corner B) can be turned in the center to perform parallel parking. Moreover, in order to determine the entry pattern based on the change in the measured distance when the vehicle V enters the parking space PS, and to set the approach angle calculation formula and the parking availability judgment condition formula according to this approach pattern, the vehicle It is possible to accurately determine whether V can park in parallel in the parking space PS. For this reason, the driver can easily perform parallel parking without performing a steering wheel operation.

  Further, since the turning center of the vehicle V is set in advance, there is no need to sequentially calculate the turning center and the target turning angle during parallel parking, and the turning trajectory of the vehicle V is constant. Easy. In particular, when the parking space PS is surrounded by a U-shape by the walls WL, WC, and WR as in the present embodiment, the accuracy of determining whether to park is high even with simple calculations. Therefore, the calculation load of the steering ECU 50 is reduced, and high specifications are not required for the calculation circuit such as a microcomputer.

  In addition, when it is determined that the approach position of the vehicle V is inappropriate and parallel parking is not possible in the parking space PS, the voice announcement device 16 announces a request to the driver to reinsert the vehicle head VF into the parking space PS. . And the movement method (entrance method to the parking space PS of the vehicle head part VF) according to the cause of parking impossibility is announced. Therefore, the driver can reinsert the vehicle head portion VF at the appropriate position of the parking space PS according to the announcement. As a result, parallel parking can be easily performed even in a narrow parking space PS.

  In addition, since the driver's preferred boarding / alighting space (α2) can be set using the boarding / alighting space selection switch 25c, it is possible to prevent a problem that the boarding / alighting space selection switch 25c is too narrow to be able to get on and off.

In addition, since the four-wheel W _FL , W _FR , W _RL , W _RR is applied to a four-wheel independent drive type 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.

  As a result, good parallel parking assistance can be obtained even with a simple parking assistance control system configuration that reduces the computational burden on the steering ECU 50.

  Although this parallel parking support control routine describes an example of turning the vehicle V in the left direction and performing parallel parking, it turns in the direction selected by the turning direction selection switch 25b and performs parallel parking. is there. Therefore, it is only necessary to store the parking availability determination condition formula and the vehicle approach angle calculation formula in the program for each of the right turn and the left turn and use them properly.

Further, when the vehicle V is taken out of the parking space PS, the target turning angle of the wheels W _FL , W _FR , W _RL , W _RR is set to the parallel parking turning angle δ _FLP , δ _FRP , The turning control may be performed by setting to δ _RLP and δ _RRP . For example, the turning end determination distance D0 calculated at the time of execution of the immediately preceding parallel parking support control routine is stored in the nonvolatile memory, and the wheel W _{FL while} the left rear wheel W _RL rolls backward by the turning end determination distance D0. , W _FR , W _RL , W _RR are steered so that the turning angles of the parallel parking turning angles δ _FLP , δ _FRP , δ _RLP , δ _RRP are the same. Then, after the left rear wheel W _RL rolls backward by the turning end determination distance D0, the normal steering control mode may be switched. Even in this case, the start and end of the parallel parking assistance may be announced by the voice announcement device 16.

Second Embodiment
Next, a steering device as a second embodiment will be described. In the first embodiment described above, a configuration is adopted in which the approach pattern of the vehicle V is discriminated, and parking propriety determination is performed using an approach angle calculation formula corresponding to the approach pattern and a parking propriety determination conditional expression. However, the second embodiment employs a simple configuration that does not determine the approach pattern of the vehicle V. That is, as in the first vehicle approach pattern in the first embodiment, parking assistance is performed on condition that the driver enters the vehicle head portion VF in a direction orthogonal to the parallel parking direction.

  The steering device according to the second embodiment is the same as the hardware configuration shown in FIG. 1 except that the parallel parking assistance control routine executed by the steering ECU 50 is different from the first embodiment. Accordingly, the parallel parking support control routine of the second embodiment will be described below. FIG. 11 is a flowchart showing a parallel parking support control routine of the second embodiment. This parallel parking support control routine is stored as a control program in the ROM of the steering ECU 50, and is repeatedly executed when an ignition switch (not shown) is in an ON state. In addition, about the process same as the process in the parallel parking assistance control routine of 1st Embodiment, the same step number is attached | subjected to drawing and only a brief description is given.

  When the vehicle is parked in parallel in the parking space PS, the driver causes the vehicle V to enter from the top and stop until the vehicle top VF enters the parking space PS as shown in FIG. 6B. At this time, the vehicle V is stopped in a direction orthogonal to the parallel parking direction. After stopping the vehicle V, the driver turns on the support mode selection switch 25a.

  When the ignition switch is turned on, the steering ECU 50 starts this parallel parking assistance control routine, and determines whether or not the assistance mode selection switch 25a is turned on in step S31. This determination is repeated at a predetermined cycle until the support mode selection switch 25a is turned on. When the driver turns on the support mode selection switch 25a (S31: YES), the steering ECU 50 uses the distance sensors 24a, 24b, 24c, and 24d in step S32 to measure the left front distance a, the left lateral distance b, The right front distance c and the right lateral distance d are measured.

Subsequently, in step S51, the steering ECU 50 performs parking availability determination calculation. In this parking availability determination calculation, the following parking availability determination conditional expression is used, and variables (distance, margin allowance α2) are substituted into this conditional expression to calculate the left side and the right side of each expression.

This parking availability determination conditional expression is the same as the first pattern parking availability determination conditional expression in the first embodiment. Next, in step S39, the steering ECU 50 determines that the vehicle V can be parked in parallel in the parking space PS and satisfies the inequality sign in the parking qualification condition expression when the inequality sign in the parking condition determination condition expression is satisfied. If not, it is determined that the vehicle V cannot be parked in parallel in the parking space PS. When it is determined that parallel parking is possible (S39: YES), the steering ECU 50 announces the start of turning parking by the voice announcement device 16 in step S40, and in step S41, the wheels W _FL , W _FR , The steering is controlled so that W _RL and W _RR become the parallel parking turning angles δ _FLP , δ _FRP , δ _RLP , and δ _RRP .

Subsequently, in step S42, the steering ECU 50 detects the rolling distance D _RL of the left rear wheel W _RL and determines whether or not the detected rolling distance D _RL has reached the turning end determination distance D0. . Then, until the rolling distance D _RL reaches the end of the turn determination distance D0, and continued turning control, the rolling distance D _RL is determined to have reached the end of the turn determination distance D0 (S42: YES), in Step S43 Then, the voice announcement device 16 utters a message that the turn is finished. With this announcement, the driver increases the brake stepping force and stops the vehicle V.

  On the other hand, if it is determined in step S39 that parallel parking is not possible, in step S44, the voice announcement device 16 is activated to notify the driver of a redo instruction and advice on moving method.

  If the distance a and the distance c measured in step S32 are different, it can be determined that the vehicle V is entering the parking space PS at an angle. I can't make a decision. Therefore, in such a case, it is determined that parking is not possible without performing the calculation process of step S51, and the voice announcement device 16 is operated in step S44 to issue an instruction to cause the vehicle V to enter the parking space PS at a right angle. It is good to.

  The parallel parking support control routine of the second embodiment is temporarily terminated when the process of step S43 or step S43 is performed.

  According to the steering device of the second embodiment described above, in order to determine whether or not parallel parking is possible under the condition that the vehicle head portion VF enters the parking space PS at a right angle to the parallel parking direction, the distance a, There is no need to capture changes in b, c, d. Therefore, it is not necessary to store the distance detection data at a predetermined cycle, and the storage capacity of the storage device can be reduced. In addition, the calculation burden on the microcomputer is further reduced, and it can be implemented at a much lower cost. Of course, as in the first embodiment, the driver does not need to operate the steering wheel and can easily perform parallel parking. In addition, when the approach position of the vehicle V is inappropriate, the driver is notified of the request for re-insertion into the parking space PS and the moving method, so that the vehicle V can be re-entered at an appropriate position.

  As mentioned above, although the steering apparatus 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 driver is notified of redoing using the voice announcement device 16, but may be configured to be visually notified using a screen display or the like.

  In the present embodiment, the notification is made not only at the start of the turn but also at the end of the turn. This is because the driver can easily check the surrounding situation during the turn and thus can easily grasp the vehicle stop timing.

  In this embodiment, the turning direction of the vehicle is set based on the selection setting of the turning direction selection switch 25b. However, the direction indicated by the turn signal (direction indicator) may be used instead of the turning direction selection switch 25b. . In this case, a winker switch signal may be input to the steering ECU 50 so that the direction indicated by the winker is recognized on the steering ECU 50 side. Further, it is not always necessary to have a function of selecting the turning direction, and a configuration in which the turning direction is fixed may be used.

  Moreover, in this embodiment, although the function which determines whether parallel parking is possible in the parking space PS based on the approach position and vehicle body size of the vehicle V is provided, it does not have the parking permission determination function. It may be a configuration.

  Of the processes performed by the steering ECU 50 in the parallel parking assistance control routine, the processing unit performing step S32 corresponds to the vehicle entry position detecting means of the present invention, and the processing unit performing step S34 is the entry pattern discrimination of the present invention. The processing unit that performs steps S35 and S36 corresponds to the means, and the processing unit that performs step S37 corresponds to the determination condition selection unit of the present invention, and the processing that performs steps S34 to S39. The unit corresponds to the parking availability determination unit of the present invention, the processing unit that performs step S41 corresponds to the parking turning angle setting unit of the present invention, and the processing unit that performs step S44 and the voice announcement device 16 include the notification unit of the present invention. It corresponds to.

1 is a schematic configuration diagram illustrating a steering device according to an 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 an embodiment. It is explanatory drawing showing the turning locus | trajectory at the time of the parallel parking of the vehicle concerning embodiment. It is a flowchart showing the flow of the whole process by the driver | operator and steering ECU concerning 1st Embodiment. It is a flowchart showing the parallel parking assistance control routine concerning 1st Embodiment. It is explanatory drawing showing the change of the 1st approach pattern concerning 1st Embodiment, and measurement distance. It is explanatory drawing showing the 2nd approach pattern concerning 1st Embodiment, and the change of a measurement distance. It is explanatory drawing showing the 3rd approach pattern concerning 1st Embodiment, and the change of a measurement distance. It is explanatory drawing showing the 4th approach pattern concerning 1st Embodiment, and the change of a measurement distance. It is a flowchart showing the subroutine for approach pattern determination concerning 1st Embodiment. It is a flowchart showing the parallel parking assistance control routine concerning 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Steering mechanism, 12a, 12b, 12c, 12d ... Steering motor, 13a, 13b, 13c, 13d ... Motor drive circuit, 14a, 14b, 14c, 14d ... Driving motor, 15a, 15b, 15c, 15d DESCRIPTION OF SYMBOLS ... Motor drive circuit, 16 ... Voice announcement device, 21a, 21b, 21c, 21d ... Wheel steering angle sensor, 22a, 22b, 22c, 22d ... Wheel speed sensor, 23 ... Steering wheel steering angle sensor, 24a, 24b, 24c, 24d ... distance sensor, 25 ... operation input unit, 25a ... support mode selection switch, 25b ... turning direction selection switch, 25c ... boarding / exiting space selection switch, 40 ... steering handle, 50 ... steering control unit (steering ECU), 100: Wheel drive control unit (Wheel drive ECU), W _FL , W _FR , W _RL , W _RR ... Wheel, PS ... Parking Car space, R ... passage, V ... vehicle, VF ... vehicle front, WC ... front parking wall, WL ... left parking wall, WR ... right parking wall, A ... left front corner, B ... right front corner.

Claims (8)

A steering actuator that independently adjusts the steering angle of the front, rear, left and right wheels;
Turning angle detection means for detecting the turning angles of the front, rear, left and right wheels respectively;
A steering apparatus comprising: a steering control unit that drives and controls the steering actuator such that the steering angle detected by the steering angle detection unit becomes a target steering angle.
A selection operation means for the driver to select the parallel parking support mode;
A parking turning angle setting means for setting the target turning angle to a parallel parking turning angle so as to turn the vehicle around the left and right side ends of the vehicle head when the parallel parking support mode is selected; A steering apparatus characterized by comprising: When the parallel parking support mode is selected, vehicle entry position detection means for detecting the entry position of the vehicle with respect to the parking space in a state where the vehicle head has entered the parking space;
Based on the vehicle entry position and the vehicle body size with respect to the detected parking space, when the vehicle is turned from the vehicle entry position around the left and right sides of the vehicle head, the vehicles are parked in parallel in the parking space. Parking availability determination means for determining whether or not it is possible;
In the case where it is determined by the parking permission determination means that parallel parking is not possible, a notification means for notifying the driver is provided,
The parking turning angle setting means sets the target turning angle in parallel parking so that the vehicle turns around the left and right sides of the front of the vehicle when it is determined that the parking permission determination means can perform parallel parking. The steering apparatus according to claim 1, wherein the steering angle is set to a turning angle. The vehicle entry position detection means includes means for detecting the distance from the left and right separate positions of the vehicle head to the parking space boundary in the vehicle front direction,
The parking permission / inhibition determining means calculates an approach angle of the vehicle to the parking space based on the difference between the detected distances, and determines whether or not the vehicle can be parked in parallel by taking into account the calculated approach angle of the vehicle. The steering apparatus according to claim 2, wherein the determination is made. The vehicle approach position detecting means is
The left front distance from the left end of the front of the vehicle to the parking space boundary in the front direction of the vehicle, the right front distance from the right end of the front of the vehicle to the parking space boundary in the front of the vehicle, and from the left end of the front of the vehicle to the left of the vehicle Distance detecting means for detecting the left side distance to the parking space boundary and the right side distance from the right end of the vehicle head to the parking space boundary in the right direction of the vehicle,
The parking permission determination means includes:
Based on the distance detected by the distance detection means and the vehicle body size, it is determined whether or not the vehicle can be parked in parallel in the parking space when the vehicle is turned around the left and right side ends of the vehicle head. The steering apparatus according to claim 2 or 3, wherein The parking permission determination means includes:
An entry pattern discriminating unit for discriminating an entry pattern of the vehicle leading part with respect to the parking space based on a change in each distance detected by the distance detecting unit when the vehicle leading part enters the parking space;
An approach angle calculating means for calculating an approach angle to the parking space of the vehicle by a calculation formula corresponding to the determined approach pattern;
The steering apparatus according to claim 4, further comprising: determination condition selection means that is set according to the determined approach pattern and that selects a parking permission / inhibition determination condition including the approach angle.   The said notification means alert | reports the request | requirement of the re-entry to the parking space of a vehicle head part with respect to a driver | operator, when it determines with the said parking permission determination means not being able to carry out parallel parking. The steering device according to claim 5.   When it is determined that the parking permission determination means cannot perform the parallel parking, the notification means changes the entry position to the parking space at the head of the vehicle with respect to the driver based on a requirement that the parking permission determination condition is not satisfied. The steering apparatus according to claim 6, wherein a method is notified.   The steering apparatus according to any one of claims 2 to 7, wherein the parking permission / inhibition determining means is determined in consideration of a space for a passenger to get off the vehicle.

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