JP2011120393A - Electric vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric vehicle for avoiding collision when a front vehicle recedes and approaches an own vehicle. <P>SOLUTION: When a stop state of the own-vehicle is detected, a distance LFR with a front obstacle is a prescribed distance L1 or below, a distance LRR with a rear obstacle is a second prescribed distance L2 or above, and an absolute value of a steering angle θSTR of a steering wheel is a prescribed steering angle θS or below, the own-vehicle is controlled to be receded at low speed. When a front-vehicle recedes and approaches the own-vehicle, collision with the front vehicle can reliably be avoided while collision with the rear obstacle is avoided without receding of the own-vehicle to a direction which a driver does not intend. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an electric vehicle driven by a motor, and particularly to a vehicle having a collision prevention function.

  Patent Literature 1 discloses an inter-vehicle distance control device that appropriately maintains an inter-vehicle distance between a vehicle traveling in front of the host vehicle and the host vehicle.

Japanese Patent Laid-Open No. 4-193631

  However, the inter-vehicle distance control device disclosed in Patent Document 1 is based on the assumption that the preceding vehicle travels forward, and is not considered when the preceding vehicle moves backward and approaches the host vehicle, for example, on an uphill. .

  The present invention has been made paying attention to this point, and it is an object of the present invention to provide an electric vehicle capable of avoiding a collision when a forward vehicle moves backward and approaches the host vehicle.

  In order to achieve the above object, the invention according to claim 1 is a forward distance calculating means (11, 1) for calculating a distance to a front obstacle in an electric vehicle having a steering wheel and driven by a motor (23). A rear distance calculating means (12, 1) for calculating a distance to the rear obstacle, a steering angle detecting means (14) for detecting a steering angle (θSTR) of the steering wheel, and detecting a stop state of the host vehicle The vehicle stop state detecting means (13, 1), the motor control means for controlling the drive of the motor (23), and the vehicle stop state detecting means detect the vehicle stop state and the distance to the front obstacle Collision avoiding means for reversing the host vehicle when the distance to the rear obstacle is equal to or greater than a predetermined rear distance and the steering angle is equal to or less than a predetermined angle. Characterized in that it comprises a.

  The invention according to claim 2 is characterized in that the electric vehicle according to claim 1 is configured to be able to change the traveling direction by changing the direction of the current to the motor.

  According to a third aspect of the present invention, in the electric vehicle according to the first or second aspect, during the backward movement by the collision avoidance means, the output of the motor is limited according to the distance to the rear obstacle. Features.

  According to the first aspect of the present invention, the vehicle stop state is detected, the distance to the front obstacle is not more than the predetermined front distance, the distance to the rear obstacle is not less than the predetermined rear distance, and the steering angle is When the vehicle is less than a predetermined angle, the vehicle is controlled to move backward. Therefore, when the vehicle ahead moves backward and approaches the vehicle, the vehicle moves backward in a direction not intended by the driver. Therefore, it is possible to reliably avoid a collision with a preceding vehicle while avoiding a collision with a rear obstacle.

  According to the second aspect of the present invention, since the traveling direction can be changed by changing the direction of the current to the motor, the traveling can be performed in a shorter time than when the reverse gear is selected by the transmission. Thus, quick avoidance is possible.

  According to the third aspect of the present invention, since the output of the motor is limited in accordance with the distance to the rear obstacle during the backward movement by the collision avoidance means, the vehicle following the host vehicle based on the driver's accelerator operation Access to can be restricted.

It is a block diagram which shows the structure of the principal part of the electric vehicle concerning one Embodiment of this invention. It is a flowchart of the collision avoidance process performed by the control part shown in FIG. It is a flowchart of the reverse control process performed by the process of FIG. It is a figure which shows the table referred by the process of FIG. FIG. 4 is a flowchart of a reverse release process executed in the process of FIG. 3.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a block diagram showing a configuration of a main part of an electric vehicle according to an embodiment of the present invention. This electric vehicle includes a steering wheel, an accelerator pedal, a brake pedal, a side brake lever, a transmission, a shift lever (not shown) that switches the operating range of the transmission, and the like, which are basic components as an automobile, A motor 23 as a drive source, a horn 24 that emits a warning sound, a display unit 21 for performing a warning display and the like, a shift actuator 22 for switching the operating range of the transmission, a brake pedal, and a side brake lever The brake actuator 25 for performing a brake release operation at the time of reverse control, which will be described later, and a control unit that performs drive control of the display unit 21, the transmission actuator 22, the motor 23, the horn 24, and the brake actuator 25. 1 is provided.

  The electric vehicle includes an ultrasonic sensor 11 for detecting a distance (hereinafter referred to as “front distance”) LFR from a front obstacle (for example, another automobile) of the own vehicle to the own vehicle, and an obstacle behind the own vehicle. An ultrasonic sensor 12 for detecting a distance (hereinafter referred to as “rear distance”) LRR (for example, another automobile) to the host vehicle, a vehicle speed sensor 13 for detecting the vehicle speed VP, and a steering angle θSTR of the steering wheel A steering angle sensor 14 to detect, an accelerator pedal sensor 15 to detect an operation amount (depression amount) AP of an accelerator pedal, and a brake sensor 16 to detect that a brake pedal is depressed or a side brake lever is operated. And the detection signals of these sensors are supplied to the control unit 1. The steering angle θSTR takes a positive value when operated clockwise from a neutral position (straight forward position), for example, and takes a negative value when operated counterclockwise.

  The control unit 1 shapes input signal waveforms from various sensors, corrects a voltage level to a predetermined level, converts an analog signal value into a digital signal value, a central processing unit (hereinafter “ CPU ”), a storage circuit for storing a calculation program executed by the CPU, a calculation result, and the like, and an output circuit for supplying a drive signal to the display unit 21, the transmission actuator 22, and the like.

  The control unit 1 calculates the front distance LFR and the rear distance LRR based on the detection signals of the ultrasonic sensors 11 and 12.

FIG. 2 is a flowchart of the collision avoidance process performed by the CPU of the control unit 1 and is executed at predetermined time intervals.
In step S11, it is determined whether or not the emergency flag FEMG is “1”. The emergency flag FEMG is a flag that is set to “1” in the reverse control process (FIG. 3) in step S21, and a process in which the front obstacle approaches when the host vehicle is stopped and the host vehicle is moved backward is performed. Is set to “1”. If the answer to step S11 is affirmative (YES), the process immediately proceeds to step S15.

  If the answer to step S11 is negative (NO), that is, FEMG = 0, it is determined whether or not the emergency flag FEMG was “1” at the previous execution of this process (step S12). If the answer to step S14 is negative (NO), the process immediately proceeds to step S14. If the emergency flag FEMG was previously set to “1”, the reverse release process (FIG. 5) is performed to end the reverse of the host vehicle. Is executed (step S13). Thereafter, the process proceeds to step S14.

  In step S14, it is determined whether or not the vehicle speed VP is “0”, more specifically, whether or not the vehicle speed VP is equal to or lower than a predetermined low vehicle speed VPL (for example, 2 km / h). If the answer is negative (NO), that is, if the vehicle is running, the process proceeds to step S16, the emergency flag FEMG is set to “0”, and the horn is leveled and a warning is displayed (ie, step S16). When S21 or S22 and S23 are executed), the horn is stopped and the warning display is turned off (steps S17 and S18).

  If the answer to step S14 is affirmative (YES), that is, if the host vehicle is stopped, it is determined whether or not the front distance LFR is equal to or less than a first predetermined distance L1 (for example, 0.5 m) (step S15). . If this answer is negative (NO), the process proceeds to step S16. When the front distance LFR is not more than the first predetermined distance L1 in step S15, it is determined whether or not the rear distance LRR is not less than the first predetermined distance L2 (for example, 0.5 m) (step S19).

  If the answer to step S19 is negative (NO), the host vehicle is too close to the rear obstacle, so the host vehicle is not moved backward, the horn is sounded, and the warning display is turned on (steps S22 and S23). Further, the emergency flag FEMG is set to “0” (step S24).

  When the answer to step S19 is affirmative (YES), that is, when the front distance LFR is equal to or smaller than the first predetermined distance L1 and the rear distance LRR is equal to or larger than the second predetermined distance L2, the absolute value of the steering angle θSTR is equal to the predetermined steering angle θS ( For example, it is determined whether it is 10 degrees or less (step S20). If this answer is negative (NO), the process proceeds to step S22 without performing backward movement.

  If the answer to step S20 is affirmative (YES), that is, if the absolute value of the steering angle θSTR is equal to or smaller than the predetermined steering angle θS, the reverse control process shown in FIG. 3 is executed (step S21).

FIG. 3 is a flowchart of the reverse control process executed in step S21 of FIG.
In step S31, a warning display indicating that the vehicle is to be moved backward is turned on, and the shift lever is operated to the R (reverse) range (step S32).

  In step S33, the ID table shown in FIG. 4 is searched according to the rear distance LRR, and the motor drive current ID is calculated. The ID table is set to a constant value ID0 (for example, a current value corresponding to a speed of 10 km / h) in the range of the third predetermined distance L3 or less, and in the range exceeding the third predetermined distance L3, the rear distance LRR increases. The motor drive current ID is set to increase. The motor drive current ID is normally set according to the accelerator pedal operation amount AP. However, in step S33, the motor drive current ID is set to the table search value regardless of the accelerator pedal operation amount AP, and therefore based on the driver's accelerator operation. It is possible to limit the approach of the host vehicle to the rear obstacle (following vehicle).

  In step S34, the motor drive current ID calculated in step S33 is supplied to the motor 23, and the emergency flag FEMG is set to “1” (step S35). In step S36, it is determined whether or not the brake operation flag FBR is “1”. The brake operation flag FBR is set to “1” when the brake sensor 16 detects the operation of the brake pedal or the side brake lever.

If the answer to step S36 is negative (NO), the process immediately ends. If the answer is affirmative (YES), the operated brake is released (step S37).
With the process of FIG. 3, the host vehicle moves backward at a low speed.

FIG. 5 is a flowchart of the backward release process executed in step S13 of FIG.
In step S41, the shift lever is operated to the D range (drive range), then the motor output restriction during reverse control is released (step S42), the current supply to the motor 23 is stopped (step S43), and the brake flag is set. When FBR is “1”, the corresponding brake operation is validated (steps S44 and S45).
The reverse of the own vehicle started in step S21 is completed by the process of FIG.

  As described above, in this embodiment, the stop state of the host vehicle is detected, the front distance LFR is equal to or smaller than the first predetermined distance L1, the rear distance LRR is equal to or larger than the second predetermined distance L2, and the steering angle θSTR is set. When the absolute value is equal to or smaller than the predetermined steering angle θS, control for moving the host vehicle backward is performed. Therefore, when the front vehicle moves backward and approaches the host vehicle, the driver moves in a direction not intended by the driver. It is possible to reliably avoid a collision with a preceding vehicle while avoiding a collision with a rear obstacle without the vehicle moving backward.

  In the present embodiment, the steering angle sensor 14 corresponds to a steering angle detection unit, the vehicle speed sensor 13 and the control unit 1 constitute a vehicle stop state detection unit, and the ultrasonic sensors 11 and 12 and the control unit 1 calculate a forward distance. The transmission actuator 22, the motor 23, the brake actuator 25, and the control unit 1 constitute a collision avoidance unit, and the control unit 1 constitutes a motor control unit.

  The present invention is not limited to the embodiment described above, and various modifications can be made. For example, in the above-described embodiment, the shift lever is operated to the R range when the host vehicle is moved backward. However, the direction of the current supplied to the motor 23 is reversed so that the vehicle can move backward. In the process of FIG. 3, a current in the direction opposite to the forward direction may be supplied to the motor 23 without moving the shift lever. As a result, it is possible to retreat in a shorter time than when the reverse gear is selected by the transmission, and quick avoidance is possible.

1 Control unit (vehicle stop state detection means, forward distance calculation means, backward distance calculation means, motor control means, collision avoidance means)
11, 12 Ultrasonic sensor (forward distance calculating means, backward distance calculating means)
14 Steering angle sensor (steering angle detection means)
22 Variable speed actuator (collision avoidance means)
23 Motor (collision avoidance means)
25 Brake actuator (collision avoidance means)

Claims (3)

In an electric vehicle equipped with a steering wheel and driven by a motor,
Forward distance calculating means for calculating the distance to the front obstacle;
A rear distance calculating means for calculating a distance to the rear obstacle;
Steering angle detecting means for detecting the steering angle of the steering wheel;
Vehicle stop state detecting means for detecting the stop state of the host vehicle;
Motor control means for controlling drive of the motor;
The vehicle stop state detecting means detects the vehicle stop state, the distance to the front obstacle is not more than a predetermined front distance, the distance to the rear obstacle is not less than a predetermined rear distance, and the steering angle is predetermined. An electric vehicle comprising: a collision avoiding means for retracting the host vehicle when the angle is equal to or smaller than the angle.   The electric vehicle according to claim 1, wherein the electric vehicle is configured to be able to change a traveling direction by changing a direction of a current to the motor.   3. The electric vehicle according to claim 1, wherein during the backward movement by the collision avoidance unit, the output of the motor is limited according to a distance to the rear obstacle.

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