JP2006335239A - Parking support device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a parking support device for enabling a driver to properly acquire surrounding circumstances, and for shortening a moving time. <P>SOLUTION: An obstacle in a direction set according to a route when supporting parking is detected (steps S11, S12), and an upper limit speed is set according to the detection result of an obstacle (step S13). In this case, the upper limit speed is set so as to be lower according as the obstacle is close to the vehicle compared with such a case that the obstacle is far from the vehicle. Then, the upper limit speed is set so as to be high during a brake operation (steps S14, S15). The set upper limit speed is compared with a vehicle speed (step S16), and when the vehicle speed exceeds the set upper limit speed, warning is issued to the driver (step S17). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a parking assistance device that supports movement to a target parking position set by automatic steering or steering assistance.

  As a device that supports a driver's parking operation, a parking support device that sets a target parking position, sets a route to the set parking position, and performs automatic steering and steering support so that movement along this route can be performed is known. (For example, refer to Patent Document 1).

As the vehicle speed increases, the turning radius of the vehicle increases due to centrifugal force, and the amount of steering per hour is required even when moving on the same route. In order to suppress the deviation of the vehicle trajectory from the set route, the vehicle speed is limited.
JP 2001-1929 A

  By the way, when parking, there are many cases of approaching obstacles such as surrounding parked vehicles, pedestrians, utility poles, guardrails, garages and parking poles. The range to be grasped is wider than that during normal driving. This range changes depending on the amount of steering, vehicle speed, and surrounding conditions, but if the vehicle speed at which the driver can properly grasp the situation under severe conditions is set as the upper limit vehicle speed, the time required for parking operation becomes longer. End up. On the other hand, if the upper limit vehicle speed is set high, a driver who is not accustomed cannot reliably grasp the surrounding situation.

  Then, this invention makes it a subject to provide the parking assistance apparatus which enabled the driver | operator to grasp | ascertain the surrounding condition appropriately, and also shortened travel time.

  In order to solve the above problems, a parking support device according to the present invention detects a vehicle speed and a distance to an object around the vehicle in a parking support device that supports movement of the vehicle to a target parking position. And vehicle speed limiting means for limiting the vehicle speed of the host vehicle at the time of parking assistance to the upper limit vehicle speed or less according to the detected distance to the object, the vehicle speed limiting means, the farther the distance to the object is The upper limit vehicle speed is increased.

  The support for moving the vehicle to the target parking position is, for example, setting a route to the target parking position, and performing automatic steering or a steering instruction so that movement along the route can be performed. At this time, the vehicle speed is controlled to be equal to or lower than the upper limit vehicle speed. Then, an object (obstacle) and a distance around the vehicle are detected by a radar, a sonar, a camera, and the like, and the upper limit vehicle speed is increased as the object is further away. Thereby, when approaching an obstacle and contact is expected, the vehicle speed is lowered to make it easier for the driver to recognize the approach to the obstacle. On the other hand, when the distance from the obstacle is sufficient, the upper limit vehicle speed is increased so that the vehicle can move on the route set in a short time.

  Storage means for storing the relationship between the detected distance to the object and the upper limit vehicle speed is further provided, and the vehicle speed limiting means may change the upper limit vehicle speed based on the relationship stored in the storage means. For example, there is a method in which the relationship between the upper limit vehicle speed is defined according to the direction / distance of the obstacle and the moving direction of the vehicle and stored in the storage means, and the upper limit vehicle speed is changed by combining these.

  The vehicle may further include a unit that detects a brake operation amount of the driver, and the vehicle speed limiting unit may change the upper limit vehicle speed according to the detected brake operation amount. That is, when the brake operation amount is 0, the upper limit vehicle speed is set, and the braking system and the drive system are controlled so as to decelerate according to the brake operation amount.

  When the vehicle speed exceeds the upper limit vehicle speed, it is preferable that alarm means for notifying the driver is further provided. As alarm means, there are a buzzer, sound, meter display, a device that vibrates the steering wheel and seat, an automatic braking device, a support release, and the like.

  According to the present invention, since the upper limit vehicle speed is changed according to the distance to the obstacle, the upper limit vehicle speed is set to a higher value when there is a margin in the distance to the obstacle. On the other hand, when the distance to the obstacle is close, the upper limit vehicle speed is set low, so that the vehicle speed is reduced to prevent inadvertent approach to the obstacle, and to promote obstacle recognition and contact avoidance. it can.

  In particular, the relationship between the upper limit vehicle speed and the distance to the detected object is stored in the storage means, and the upper limit vehicle speed is appropriately set according to the vehicle speed, distance, and direction, so that it is appropriate for the positional relationship between the obstacle and the vehicle. Control can be performed.

  Further, by controlling the vehicle speed below the upper limit vehicle speed set according to the amount of brake operation, the driver can adjust the vehicle speed only by the brake operation, and the parking operation can be simplified.

  When a notification means for notifying the driver that the upper limit vehicle speed has been exceeded is provided, the approach to the obstacle can be reliably suppressed to improve safety, and the reliability of the parking assistance device is also improved. .

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the accompanying drawings. In order to facilitate the understanding of the description, the same reference numerals are given to the same components in the drawings as much as possible, and duplicate descriptions are omitted.

  FIG. 1 is a block diagram of a parking assistance apparatus 100 according to the present invention. The parking assistance device 100 according to the present embodiment includes a travel control device 110 and an automatic steering device 120, and is controlled by a parking assistance ECU 1 that is a control device. The parking assist ECU 1 includes a CPU, a ROM, a RAM, an input signal circuit, an output signal circuit, a power supply circuit, and the like, and a travel control unit 10 that controls the travel control device 110 (also serves as a vehicle speed control unit according to the present invention). And a steering control unit 11 for controlling the automatic steering device. The travel control unit 10 and the steering control unit 11 may be separated in hardware in the parking assist ECU 1, but are separated in software using the same CPU, ROM, RAM, and the like in hardware. Also good.

  The travel control device 110 includes the travel control unit 10 described above, a braking system, and a drive system. The braking system is an electronically controlled brake (ECB) system in which the braking force applied to each wheel is electronically controlled by the brake ECU 31, and the brake hydraulic pressure applied to the wheel cylinder 38 of the hydraulic brake disposed on each wheel is controlled by the actuator 34. By adjusting, it has the function to adjust independently the braking force given to each wheel.

  The brake ECU 31 is disposed in each wheel and disposed in a wheel speed sensor 32 that detects the respective wheel speeds, an acceleration sensor 33 that detects vehicle acceleration, and an actuator 34, and is added to the inside and the wheel cylinder 38. Output signals of a master cylinder (M / C) oil pressure sensor 36 for detecting the oil pressure of a master cylinder 35 connected between the brake pedal 37 and the actuator 34. Is entered.

  The engine 22 constituting the drive system is controlled by the engine ECU 21, and the engine ECU 21 and the brake ECU 31 communicate with each other and perform cooperative control with the travel control unit 10. Here, the output of the shift sensor 12 that detects the shift state of the transmission is input to the engine ECU 21.

  The automatic steering device 120 includes a drive motor 42 that also serves as a power steering device disposed between the steering wheel 40 and the steering gear 41, and a displacement sensor 43 that detects a displacement amount of the steering, and the steering control unit 11 is driven. While controlling the drive of the motor 42, the output signal of the displacement sensor 43 is input.

  The parking support ECU 1 including the travel control unit 10 and the steering control unit 20 includes an input unit 16 that receives an image signal acquired by the rear camera 15 for acquiring an image behind the vehicle and a driver's operation input for parking support. Are connected to a monitor 13 that displays information by an image to a driver and a speaker 14 that presents information by voice. The monitor 13 and the speaker 14 constitute alarm means according to the present invention.

  Further, sonars 17 for detecting obstacles around the vehicle are arranged at the front, rear and four corners of the vehicle 5, and the output of the sonar 17 (distance from the obstacles) is input to the parking assist ECU 1. . FIG. 2 shows an arrangement example of the sonar 17 on the vehicle. Hatching indicates the sensing area of each sonar 17, and the number is indicated by a number in a circle. For example, the sonar 17 determines the distance to an obstacle when the presence or absence of the obstacle exists based on the time until the ultrasonic wave is periodically transmitted and the reflected wave is received. is there. A radar may be used in place of the sonar 17, and the presence / absence of an obstacle and the distance to the obstacle may be determined by performing image processing on an image acquired by a camera.

  Next, the parking assistance process using this parking assistance apparatus is demonstrated concretely. FIG. 3 is a flowchart for explaining the parking assistance process, and FIG. 4 is a diagram for explaining the route of the own vehicle in the parking assistance. Hereinafter, the case where the vehicle 5 is parked in the garage 7 facing the road 6 will be described as an example.

First, after moving the vehicle 5 to the position shown in FIG. 4, the driver operates the input unit 16 while viewing the image captured by the rear camera 15 displayed on the monitor 13, thereby entering the parking assistance mode. The target parking position is set by setting and moving the parking frame displayed on the screen to the position 5t in FIG. Hereinafter, the center of gravity of the vehicle is P (x, y), and the center of gravity of the target parking position 5t is represented by Pt (x _t , y _t ).

  When the setting of the target parking position 5t is completed, the parking assist ECU 1 starts the process shown in FIG. First, in step S1, an initial value of 0 is set in the route setting completion flag Xset to the parking position. When this Xset is 1, it means that the route to reach the target position 5t is set, and when it is 0, it means that the setting has not been completed.

Subsequently, in step S2, determined from the current position P (x, y) target parking position Pt (x _t, y _t) the route to. More specifically, first, the position of Pt (x _t , y _t ) is obtained in advance by image recognition processing. Here, the target position Pt (x _t , y _t ) may be obtained as relative coordinates with the current vehicle position P (x, y) as the origin, for example. Next, the parking assist ECU1 finds the path 51 of the optimum vehicle center of gravity leading to P (x, y) from the target position _{Pt (x t, y t)} . At this time, the rudder angle and the rudder angle operation amount with respect to the route position are calculated so as to fall within the rudder angle and rudder angle operation amount that can be set by the automatic steering device 120. If the current initial steering angle cannot set the movement route to the target parking position Pt (x _t , y _t ), the initial steering angle may be changed or the initial position may be changed. Good. If the route can be set, 1 is set in Xset. If the route cannot be set, for example, if the change of the initial steering angle and the initial position is urged, 0 is set in Xset.

  Subsequently, the value of Xset is checked in step S3, and the process proceeds to the next step S4 only when it is 1, and when it is 0, when the rudder angle change or initial position change is waited until the change is completed, then step Return to S2. As a result, a route to reach the target position is set.

  In step S4, the driver is stepped on the brake pedal 37 to instruct to operate the shift lever to set the vehicle in reverse, and waits until the condition is satisfied. In step S5, the travel control unit 10 of the parking assist ECU 1 instructs the engine ECU 21 to torque up the engine 22, and starts automatic steering. Due to the torque increase, the engine 22 rotates at a higher rotational speed than during normal idling, thereby shifting to a torque-up state with a high driving force. For this reason, the vehicle speed range that can be adjusted only by the brake pedal 37 without performing the accelerator operation is expanded, and the controllability of the vehicle is improved.

  Here, when the driver operates the brake pedal 37, the wheel cylinder hydraulic pressure (brake hydraulic pressure) applied to the wheel cylinder 38 is adjusted by the actuator 34 according to the pedal opening, and the braking force applied to each wheel is adjusted. By adjusting, the vehicle speed is adjusted by changing the balance between the braking force and the driving force. If there are obstacles, pedestrians, etc. on the path, when the driver depresses the brake pedal 37, the braking force corresponding thereto is applied to the wheel cylinder 38 via the actuator 34 under the control of the brake ECU 31, which is safe. You can slow down and stop.

  In step S6, based on the vehicle speed change obtained from the wheel speed obtained from the wheel speed sensor 32, the acceleration change obtained from the acceleration obtained from the acceleration sensor 33, and the steering angle change obtained from the displacement sensor 43, Calculate the position.

  The steering control unit 11 controls the drive motor 42 and operates the steering gear 41 while monitoring the output of the displacement sensor 43 so that the steering angle becomes the steering angle displacement corresponding to the position obtained by the parking assist ECU 1. Control (step S7).

  In step S8, it is determined whether or not the current position P has reached the target position Pt. In this determination, it may be determined whether or not the current position P has reached a predetermined area near the target position Pt. The size of this area should be set based on the accuracy of image recognition of the image acquired from the rear camera 15, the accuracy of determination of the current position obtained from the vehicle speed, acceleration, etc., the steering accuracy of the automatic steering device 120, etc. Good.

  If it is determined that the target position has not been reached, the process returns to step S6 and the process is repeated to move the vehicle 5 along the route set to the target position Pt without the driver performing a steering wheel operation. Thus, the driver can concentrate on the safety confirmation on the road and the vehicle speed adjustment, and the parking operation is simplified.

  If it is determined that the vicinity of the target position Pt has been reached, the process proceeds to step S9, where the traveling control unit 10 instructs the engine ECU 21 to decrease the rotational speed of the engine 22, performs torque reduction, and the steering control unit. 11 ends the automatic steering control. In step S10, the driver is informed through the monitor 13 and the speaker 14 that the target parking position has been reached, and the shift lever is set to the parking position, prompting the engine to stop, and the process ends. To do.

  Next, the vehicle speed adjustment described above will be specifically described. FIG. 5 is a flowchart showing the vehicle speed adjustment control process. This process is repeatedly executed at a predetermined timing in parallel with the processes of steps S6 to S8 in FIG.

  First, the sonar 17 that should read the detection result is set according to the route (step S11). For example, when entering the garage by turning left, there is a possibility that the rear and right front of the vehicle may come into contact with an obstacle. On the other hand, when entering the garage by turning right, there is a possibility that the rear and left front of the vehicle may come into contact with an obstacle. Therefore, the sonar 17 of No. 1, No. 2, No. 7 to No. 10 is set as the target sensor. Since parallel parking can express a route as a combination of a right turn backward and a left turn backward, while targeting sonar 17 of No. 7 to No. 10 on all routes, depending on the position of the route (whether it is turning right or left), Switch between No. 2 and 5 and 6 sonars 17. When the vehicle is moving straight forward, only the 7th to 10th sonars 17 may be targeted.

  When the target sonar 17 is determined, the detection results of those sonars 17 are read (step S12). Next, an upper limit vehicle speed is set according to the route position (whether on a curve or a straight road) and the detection result of each sonar 17 (step S13). For example, on the curve, it is necessary to consider not only the rear but also the front end opposite to the turning direction. Therefore, the upper limit vehicle speed is set to be lower than that when the vehicle is traveling straight ahead and only needs to pay attention to the rear. When an obstacle is detected by the same sonar 17, the upper limit vehicle speed is set lower than when the obstacle is closer, as compared with the case where the obstacle is farther away.

  When the sonar 17 that detected the obstacle is different, that is, when the positional relationship between the obstacle and the vehicle is different, the following setting is made. For example, since the obstacle detected by the rear sonar 17 is an obstacle on the course, it is necessary to make the object to be decelerated even when it is relatively far away, but the obstacle detected by the sonar 17 at the left and right ends has a distance. If it is sufficiently far away, the possibility of contact is low. Therefore, when the distance of the obstacle detected by the sonar 17 at the left and right ends is a predetermined distance or more, it may be handled in the same manner as when no obstacle is detected. Further, the way of lowering the upper limit vehicle speed may be varied depending on the position of the sonar 17 that is detected even for an obstacle at a short distance. When obstacles in different directions are detected simultaneously by a plurality of sonars 17, the upper limit vehicle speed is lowered with reference to the nearest obstacle, and the lowest upper limit vehicle speed among the upper limit vehicle speeds set for each obstacle is set. A method such as selection may be used. Furthermore, in consideration of the presence of a plurality of obstacles, the upper limit vehicle speed may be lowered as compared with the case of one obstacle. These settings may be performed by storing the settings in a nonvolatile RAM or other storage device in the parking assist ECU 1 in a map format and reading the settings.

  When the upper limit vehicle speed is set, it is further determined whether or not the brake is being operated (step S14). Here, it is determined that the brake is being operated when the brake pedal 37 is operated with a depressing force of a predetermined level or more from the output of the M / C hydraulic sensor 36. If the brake is being operated, the upper limit vehicle speed set in step S13 is increased (step S15). When the driver is actively operating the brake while assisting, there is a high possibility that the driver has already recognized the obstacle and is decelerating. In this case, as will be described later, if a warning that the upper limit vehicle speed has been exceeded is given, the driver may feel that the warning is troublesome. By setting the upper limit vehicle speed higher during braking operation than when not operating, this type of warning is less likely to occur and the occurrence of warnings contrary to the driver's expectations is suppressed. After the upper limit vehicle speed is set, the process proceeds to step S16, and the current vehicle speed is compared with the upper limit vehicle speed. On the other hand, if it is determined in step S14 that the brake is not being operated, the process proceeds to step S16 as it is.

  When the current vehicle speed exceeds the upper limit vehicle speed, the monitor 13 and the speaker 14 notify that the upper limit vehicle speed is exceeded (step S17), prompts the driver to decelerate, and ends the process. In this case, the brake ECU 31 may further adjust the braking force so that a predetermined deceleration is applied. Specifically, control is performed to increase the hydraulic pressure supplied to the wheel cylinder 38 of each wheel. In this way, when the vehicle speed exceeds the upper limit vehicle speed, the necessary deceleration can be automatically performed.

  If it is determined in step S17 that the upper limit vehicle speed has not been exceeded, the processing ends. In this case, if an alarm is already being issued, the alarm is canceled. The warning when the upper limit vehicle speed is exceeded may be given when the state where the upper limit vehicle speed is exceeded continues for a predetermined time, and the release may be performed after the state where the upper limit vehicle speed is lower than the upper limit vehicle speed continues for a predetermined time. preferable. If the alarm is started and canceled only at the temporary vehicle speed at the time of the judgment, the alarm may be started and canceled frequently when traveling near the upper limit vehicle speed, which is annoying to the driver. This is because there is a risk of deteriorating the reliability of alarms.

  In addition, after reaching a predetermined position on the parking route, the change in the upper limit vehicle speed may be limited to the direction in which the upper limit vehicle speed is changed, and may not be changed in the increase direction (prohibition of the upper limit vehicle speed return). Even in this case, when the parking support operation is ended or canceled, the prohibition of the upper limit vehicle speed return is canceled. When reaching the vicinity of the target parking position, it is preferable to refrain from the acceleration operation from the viewpoint of safety. By prohibiting the return of the upper limit vehicle speed, the acceleration operation near the target parking position can be suppressed.

  According to the present embodiment, an appropriate upper limit vehicle speed can be set according to the route position and the positional relationship between the vehicle and the obstacle, so that the movement to the target parking position is shortened and the obstacle is close. Can encourage the driver to slow down and allow the driver to grasp the obstacle. For this reason, contact with an obstacle can be prevented.

  In the above description, the case where automatic steering is performed has been described as an example. However, the steering amount may be instructed by voice or the like, and actual steering may be steering assistance that the driver performs. Although an example in which the driving force is increased from the normal time has been described here, the driving force is not changed from the normal time, and the present invention is also suitable when the vehicle speed control is performed by the driver operating the brake and the accelerator. Applicable to.

It is a block block diagram of the parking assistance apparatus 100 which concerns on this invention. The vehicle arrangement example of the sonar 17 in the vehicle carrying the apparatus of FIG. 1 is shown. It is a flowchart explaining a parking assistance process. It is a figure explaining the path | route of the own vehicle in parking assistance. It is a flowchart which shows the process of vehicle speed setting control.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Parking assistance ECU, 5 ... Vehicle, 5t ... Target parking position, 6 ... Road, 7 ... Garage, 10 ... Driving control part, 11 ... Steering control part, 12 ... Shift sensor, 13 ... Monitor, 14 ... Speaker, 15 ... rear camera, 16 ... input means, 17 ... sonar, 20 ... steering control unit, 21 ... engine ECU, 22 ... engine, 31 ... brake ECU, 32 ... wheel speed sensor, 33 ... acceleration sensor, 34 ... actuator, 35 ... Master cylinder, 36 ... hydraulic sensor, 37 ... brake pedal, 38 ... wheel cylinder, 40 ... steering wheel, 41 ... steering gear, 42 ... drive motor, 43 ... displacement sensor, 51 ... path, 100 ... parking assist device, 110 ... Travel control device, 120 ... automatic steering device.

Claims (4)

In the parking assistance device that supports the movement of the vehicle to the target parking position,
Means for detecting the vehicle speed;
Means for detecting a distance to an object around the vehicle;
Vehicle speed limiting means for limiting the vehicle speed of the host vehicle at the time of parking assistance to an upper limit vehicle speed or less according to the distance to the detected object,
The parking assist device according to claim 1, wherein the vehicle speed limiting means increases the upper limit vehicle speed as the distance to the object increases.   The apparatus further comprises storage means for storing the relationship between the detected distance to the object and the upper limit vehicle speed, wherein the vehicle speed limiting means changes the upper limit vehicle speed from the relationship stored in the storage means. The parking assistance device according to claim 1.   3. The vehicle according to claim 1, further comprising means for detecting a driver's brake operation amount, wherein the vehicle speed limiting means changes the upper limit vehicle speed according to the detected brake operation amount. The parking assistance device described. The parking assist device according to any one of claims 1 to 3, further comprising alarm means for notifying a driver when the vehicle speed exceeds the upper limit vehicle speed.

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