JP2008210036A - Obstacle detection apparatus and obstacle detection method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an obstacle detection apparatus capable of preventing the generation of overflow during coordinate operation even when an absolute coordinate system is used. <P>SOLUTION: The obstacle detection apparatus 1 is provided with an obstacle detection ECU 20 for controlling the whole apparatus. A millimeter wave radar 10, a steering angle sensor 11, a wheel speed sensor 12, etc. are connected to the obstacle detection ECU 20. In the obstacle detection ECU 20, an own vehicle coordinate acquisition part 21 for acquiring the positional coordinates of its own vehicle in the absolute coordinate system, an obstacle coordinate acquisition part 22 for acquiring the positional coordinates of an obstacle existing around the own vehicle in the absolute coordinate system, a storage part 23 for storing the positional coordinates of the own vehicle and the positional coordinates of the obstacle, and an origin reset part 24 for setting the positional coordinates of the own vehicle at prescribed timing as the origin of the absolute coordinate system at the prescribed timing and moving the positional coordinates of the obstacle stored in the storage part 23 in parallel in accordance with origin reset are constructed. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an obstacle detection apparatus and an obstacle detection method using an absolute coordinate system.

Patent Document 1 discloses a parking assistance device that creates an obstacle map using an absolute coordinate system (world coordinate system). That is, in the parking assist device, the position of the host vehicle when the start switch is turned on is set as the origin of the absolute coordinate system, and the absolute value is based on the output signals of the vehicle speed sensor and the steering sensor from the time when the start switch is turned on until the current time. In addition to deriving the yaw angle of the host vehicle in the coordinate system and the current coordinate of the host vehicle, the distance to the obstacles such as other vehicles and road structures around the host vehicle is determined by the corner sensor etc. To derive. An obstacle map in which obstacle candidates are superimposed on a map around the vehicle by registering a point having a distance substantially equal to the distance to the obstacle as a candidate for obstacles around the vehicle in a built-in memory such as a RAM. Have created.
JP 2001-334897 A

  Here, for example, when information processing is performed with a single precision floating point, the range of values that can be handled is ± 8388608, and if the accuracy of the target (obstacle) coordinates is 0.01 m, the value is up to 8338886.08 m. Can only handle. For this reason, when an absolute coordinate system (world coordinate system) is used as the map coordinate system, if the movement distance from the origin becomes long, an overflow may occur during coordinate calculation by the electronic control unit.

  The present invention has been made to solve the above problems, and provides an obstacle detection device capable of preventing overflow during coordinate calculation even when an absolute coordinate system is used. Objective.

  The obstacle detection device according to the present invention acquires own vehicle coordinate acquisition means for acquiring the position coordinates of the own vehicle in an absolute coordinate system, and acquires the position coordinates of an obstacle existing around the own vehicle in the absolute coordinate system. The obstacle coordinate acquisition means, the storage means for storing the position coordinates of the host vehicle and the position coordinates of the obstacle, and at the predetermined timing, the position coordinates of the host vehicle at the timing are set as the origin of the absolute coordinate system. And an initialization means for moving the position coordinates of the obstacle stored in the storage means in response to the resetting.

  The obstacle detection method according to the present invention includes a vehicle coordinate acquisition step for acquiring a position coordinate of the host vehicle in an absolute coordinate system, and a position coordinate of an obstacle existing around the host vehicle in the absolute coordinate system. The obstacle coordinate acquisition step to be acquired, the storage step of storing the position coordinate of the host vehicle and the position coordinate of the obstacle, and at the predetermined timing, the position coordinate of the host vehicle at the timing is set as the origin of the absolute coordinate system, And an initialization step of moving the position coordinates of the obstacle stored in the storage step in response to the resetting of the origin.

  According to the obstacle detection device or the obstacle detection method according to the present invention, the position coordinate of the host vehicle is returned to the origin of the absolute coordinate system at a predetermined timing, and is stored corresponding to such reset of the origin. The position coordinates of the obstacle is also moved. Therefore, the origin can be reset at every predetermined timing while maintaining the positional relationship between the host vehicle and the obstacle on the absolute coordinates. As a result, even when an absolute coordinate system is used, it is possible to prevent overflow during coordinate calculation.

  An obstacle detection apparatus according to the present invention includes a yaw angle detection unit that detects a yaw angle of the host vehicle, the storage unit stores yaw angle information of the host vehicle, and the reset unit includes an origin of an absolute coordinate system. When resetting, it is preferable to hold the yaw angle information of the host vehicle stored in the storage means.

  The obstacle detection method according to the present invention further includes a yaw angle detection step of detecting the yaw angle of the host vehicle. In the storage step, yaw angle information of the host vehicle is stored. In the initialization step, absolute coordinates are stored. When resetting the origin of the system, it is preferable to retain the yaw angle information of the host vehicle stored in the storing step.

  When the yaw angle information of the own vehicle is used to acquire the position coordinates of the own vehicle in the absolute coordinate system, it is conceivable that the yaw angle information is also returned to the initial state when the origin of the absolute coordinate system is reset. However, if the yaw angle information is to be reset, the position coordinates of the obstacle need to be translated and rotated. Here, in order to rotate and move the position coordinates, an operation using a trigonometric function is required, so that an operation cost (operation load) of processing increases. On the other hand, the yaw angle does not exceed 360 degrees and is not integrated like the position information.

  According to the obstacle detection device or the obstacle detection method according to the present invention, when the origin of the absolute coordinate system is reset, the stored yaw angle information of the host vehicle is held without being reset. That is, it is not necessary to perform an operation for rotating the position coordinates of the obstacle at every predetermined timing. Therefore, it is possible to prevent overflow of the position map without increasing the calculation cost (calculation load).

  According to the present invention, at a predetermined timing, the position coordinate of the host vehicle at the timing is set as the origin of the absolute coordinate system, and the position coordinate information of the obstacle stored in the storage means in response to the reset of the origin is obtained. Since the configuration is reset, it is possible to prevent overflow during coordinate calculation even when an absolute coordinate system is used.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In the figure, the same reference numerals are used for the same or corresponding parts.

  First, the overall configuration of the obstacle detection apparatus 1 according to the embodiment will be described with reference to FIG. FIG. 1 is a block diagram showing the overall configuration of the obstacle detection apparatus 1.

  The obstacle detection device 1 acquires and stores the position coordinates of the host vehicle and the obstacles existing around the host vehicle in the absolute coordinate system at a predetermined cycle. Further, the obstacle detection device 1 returns the position coordinates of the host vehicle to the origin of the absolute coordinate system at a predetermined timing, and translates the position coordinates of the obstacle in response to the reset of the origin. The obstacle detection device 1 according to the present embodiment is provided with a collision prediction function for predicting whether or not the host vehicle and the obstacle collide based on a change in position coordinates of the host vehicle and the obstacle. It is a thing.

  For this purpose, the obstacle detection device 1 includes an electronic control device (hereinafter referred to as “obstacle detection ECU (Electronic Control Unit)”) 20 that controls the entire device. The obstacle detection ECU 20 is connected to a millimeter wave radar 10, a steering angle sensor 11, a wheel speed sensor 12, and the like.

  The millimeter wave radar 10 detects the presence or absence of an obstacle such as another vehicle, and detects the direction of the obstacle, the distance to the obstacle, and the relative speed when the obstacle is detected. The millimeter wave radar 10 detects the distance from the obstacle according to the time from the irradiation of the millimeter wave to the detection of the reflected wave, and detects the relative velocity with the obstacle from the change in the frequency of the reflected wave. Also, the direction of the obstacle is detected from the direction of the reflected wave. The detection result by the millimeter wave radar is output to the obstacle detection ECU 20.

  The steering angle sensor 11 is a sensor that detects the steering angle of the steering wheel operated by the driver, and outputs a steering angle signal corresponding to the steering angle to the obstacle detection ECU 20.

  The wheel speed sensor 12 detects the wheel speed of the vehicle, and outputs a wheel speed signal corresponding to the wheel speed to the obstacle detection ECU 20.

  The obstacle detection ECU 20 includes a microprocessor that performs calculations, a ROM that stores a program for causing the microprocessor to execute each process, a RAM that stores various data such as calculation results, and a backup in which the stored contents are held by a battery. It is comprised by RAM etc.

  The obstacle detection ECU 20 executes the program to obtain the vehicle coordinate acquisition unit 21 that acquires the position coordinates of the vehicle in the absolute coordinate system, and the positions of obstacles that exist around the vehicle in the absolute coordinate system. An obstacle coordinate acquisition unit 22 that acquires coordinates, a storage unit 23 that stores the position coordinates of the host vehicle and the position coordinates of the obstacle, and the position coordinate of the host vehicle at the predetermined timing is set as the origin of the absolute coordinate system. In addition, the origin reset unit 24 that translates the position coordinates of the obstacle stored in the storage unit 23 in response to the origin reset, the traveling track of the host vehicle obtained from the steering angle and the vehicle speed, and the position of the obstacle The function of the collision determination unit 25 that determines whether or not the host vehicle and the obstacle collide with each other is realized based on the movement trajectory of the obstacle obtained from the change in coordinates.

  Here, the rudder angle sensor 11, the wheel speed sensor 12, and the own vehicle coordinate acquisition unit 21 correspond to the own vehicle coordinate acquisition means described in the claims. The millimeter wave radar 10 and the obstacle coordinate acquisition unit 22 correspond to the obstacle coordinate acquisition means described in the claims. The storage unit 23 corresponds to a storage unit, and the origin reset unit 24 corresponds to an initialization unit.

  The own vehicle coordinate acquisition unit 21 acquires the position coordinates of the own vehicle in the absolute coordinate system. More specifically, first, the position of the vehicle when the ignition switch is turned on is initially set as the origin (X, Y) = (0, 0) of the absolute coordinate system. In addition, the azimuth (yaw angle) of the vehicle at that time is initially set as azimuth zero. Thereafter, the host vehicle coordinate acquisition unit 21 reads the vehicle speed obtained from the steering angle detected by the steering angle sensor 11 and the wheel speed detected by the wheel speed sensor 12 at a predetermined cycle, and from the steering angle and the vehicle speed. The moving amount and moving direction of the host vehicle (coordinates) are calculated, and the current value of the position coordinates is obtained by adding the calculation result to the previous value of the position coordinates. Also, the change amount of the yaw angle of the host vehicle is calculated from the read steering angle and vehicle speed, and the current value of the yaw angle is obtained by adding the calculation result to the previous value of the yaw angle. The acquired position coordinates and yaw angle of the host vehicle are output to the storage unit 23.

  The obstacle coordinate acquisition unit 22 acquires the position coordinates of an obstacle existing around the host vehicle in the absolute coordinate system. More specifically, in a predetermined cycle, the distance between the host vehicle and the obstacle detected by the millimeter wave radar 10 and the direction of the obstacle with respect to the host vehicle are read, and the position coordinates of the host vehicle on the absolute coordinate system and The coordinates that are separated from the azimuth by the detected distance in the detected azimuth are acquired as the position coordinates of the obstacle. The acquired position coordinates of the obstacle are output to the storage unit 23.

  The storage unit 23 stores a plurality (for example, 10) of the position coordinates of the host vehicle acquired by the host vehicle coordinate acquisition unit 21 and the position coordinates of the obstacle acquired by the obstacle coordinate acquisition unit 22 in time series.

  As shown in FIG. 2, the origin reset unit 24 returns the position coordinates of the host vehicle to the origin of the absolute coordinate system at a predetermined timing, and is stored in the storage unit 23 in response to such reset of the origin. Translate all the position coordinates of the obstacle. At that time, the yaw angle information (rotational component) of the host vehicle is held without being reset. FIG. 2 shows an example of the state before and after the origin reset is executed in order to explain the method of resetting the origin of the absolute coordinate system. In FIG. 2, the state before the origin reset is executed is indicated by a dotted line, and the state after the origin reset is executed is indicated by a solid line. In FIG. 2, V is the host vehicle, B is the other vehicle (obstacle), O is the origin, Vc is the host vehicle coordinate, Bc is the other vehicle (obstacle) coordinate, Lb is the obstacle trajectory prediction line, and Lc is The own vehicle trajectory prediction line, Pc, is a collision prediction point. In addition, “′” is added to each symbol to indicate the state before the origin reset.

  Next, an example of a predetermined timing for resetting the origin will be described. Here, the output period of the millimeter wave radar 10 is 100 msec, and the processing period of the collision determination process using the position coordinates of the own vehicle and the obstacle, that is, the calculation period of the position coordinates of the own vehicle and the obstacle is 70 msec. Assume. Thus, when the position coordinate calculation cycle is shorter than the output cycle of the millimeter wave radar 10, the detection value of the millimeter wave radar 10 is not updated from the value at the previous processing in the position coordinate calculation processing. Cases can arise. In the present embodiment, the origin reset is executed when the detection value of the millimeter wave radar 10 is not updated (predetermined timing).

  The collision determination unit 25 is based on the traveling trajectory of the host vehicle obtained from the change in the position coordinate of the host vehicle in the absolute coordinate system and the movement trajectory of the obstacle obtained from the change in the position coordinate of the obstacle such as another vehicle. To determine whether the vehicle and the obstacle collide

  Next, operation | movement of the obstruction detection apparatus 1 is demonstrated using FIG. FIG. 3 is a flowchart showing a processing procedure of the origin reset processing by the obstacle detection device 1. This process is performed by the obstacle detection ECU 20, and is repeatedly executed at a predetermined cycle (for example, 70 msec) from when the obstacle detection apparatus 1 is turned on until it is turned off.

  In step S100, the detection result by the millimeter wave radar 10 is read. Here, it is assumed that the output period of the millimeter wave radar 10 is 100 msec. In step S102, the value of the millimeter wave counter is read. Here, the millimeter wave counter is a counter that is incremented every time the detection result of the millimeter wave radar 10 is updated (that is, every 100 msec), and the detection result is updated when the value of the millimeter wave counter is incremented. When the value of the millimeter wave counter is not incremented, it indicates that the detection result is not updated.

  Subsequently, in step S104, it is determined whether or not the value of the millimeter wave counter is the same as the value at the previous processing, that is, whether or not the detection result of the millimeter wave radar 10 has been updated from the previous time. Is called. Here, when the value of the millimeter wave counter is incremented from the value at the time of the previous process, it is determined that the detection result of the millimeter wave radar 10 has been updated, and the process is temporarily exited. Then, this process is executed again at a predetermined cycle. On the other hand, when the value of the millimeter wave counter is the same as the value at the time of the previous process, it is determined that the detection result of the millimeter wave radar 10 has not been updated, and the process proceeds to step S106.

  In step S106, the position coordinates of the host vehicle are returned to the origin of the absolute coordinate system, and all the position coordinates of the obstacle stored in the storage unit 23 are translated in response to the reset of the origin. Information such as an obstacle trajectory prediction line, an own vehicle trajectory prediction line, and a collision prediction point is also translated. However, at that time, the yaw angle information (rotation component) of the host vehicle is held without being reset (see FIG. 2).

  According to this embodiment, when the detection result of the millimeter wave radar 10 is not updated, the position coordinate of the host vehicle is returned to the origin of the absolute coordinate system, and stored in response to such reset of the origin. The position coordinate of the obstacle is translated. Therefore, the origin can be reset at every predetermined timing while maintaining the positional relationship between the host vehicle and the obstacle on the absolute coordinates. As a result, even when an absolute coordinate system is used, it is possible to prevent overflow during coordinate calculation.

  Further, according to the present embodiment, when the origin of the absolute coordinate system is reset, the stored yaw angle information of the host vehicle is retained without being reset. That is, it is not necessary to perform an operation for rotating the position coordinates of the obstacle at every predetermined timing. Therefore, it is possible to prevent overflow of the position map without increasing the calculation cost (calculation load).

  Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications can be made. For example, in the above embodiment, the present invention is applied to the collision prediction for predicting whether or not the host vehicle and the obstacle collide on the absolute coordinates, but the scope of the present invention is not limited to the collision prediction, For example, the present invention can also be applied to other devices that handle the position coordinates of the host vehicle and obstacles in an absolute coordinate system, such as parking assistance.

  In the above embodiment, the origin reset is executed when the value of the millimeter wave counter is not changed, but the predetermined timing for performing the origin reset is not limited to this.

  Furthermore, in the above embodiment, the millimeter wave radar is used to detect the direction of the obstacle, the distance to the obstacle, and the relative speed. However, for example, a laser radar or a stereo camera is used instead of the millimeter wave radar. You can also.

It is a block diagram showing the whole obstacle detection device composition concerning an embodiment. It is a figure for demonstrating the reset method of the origin of an absolute coordinate system. It is a flowchart which shows the process sequence of the origin reset process by the obstruction detection apparatus which concerns on embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Obstacle detection apparatus, 10 ... Millimeter wave radar, 11 ... Rudder angle sensor, 12 ... Wheel speed sensor, 20 ... Obstacle detection ECU, 21 ... Own vehicle coordinate acquisition part, 22 ... Obstacle coordinate acquisition part, 23 ... Storage unit, 24 ... origin reset unit.

Claims (4)

Own vehicle coordinate acquisition means for acquiring the position coordinates of the own vehicle in an absolute coordinate system;
Obstacle coordinate acquisition means for acquiring position coordinates of an obstacle present around the host vehicle in the absolute coordinate system;
Storage means for storing the position coordinates of the host vehicle and the position coordinates of the obstacle;
Initially moving the position coordinates of the obstacle stored in the storage means in response to resetting the origin, with the position coordinates of the own vehicle at the timing as the origin of the absolute coordinate system at a predetermined timing And an obstacle detection device. Yaw angle detection means for detecting the yaw angle of the host vehicle,
The storage means stores yaw angle information of the host vehicle,
2. The obstacle detection according to claim 1, wherein the initialization unit retains yaw angle information of the host vehicle stored in the storage unit when the origin of the absolute coordinate system is reset. apparatus. An own vehicle coordinate acquisition step for acquiring the position coordinates of the own vehicle in an absolute coordinate system;
An obstacle coordinate acquisition step of acquiring position coordinates of an obstacle existing around the host vehicle in the absolute coordinate system;
A storage step of storing the position coordinates of the host vehicle and the position coordinates of the obstacle;
Initialization of moving the position coordinates of the obstacle stored in the storing step in response to reset of the origin, with the position coordinates of the own vehicle at the timing as the origin of the absolute coordinate system at a predetermined timing An obstacle detection method comprising the steps of: A yaw angle detection step of detecting the yaw angle of the host vehicle,
In the storing step, yaw angle information of the host vehicle is stored,
4. The obstacle detection method according to claim 3, wherein in the initialization step, when the origin of the absolute coordinate system is reset, the yaw angle information of the host vehicle stored in the storage step is retained. .

Images