JPH09304423A - Behavior detector for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve a highly accurate detection of the behavior of a vehicle during running with a simple structure, in a behavior detector of the vehicle which is designed to start the detection of the behavior of vehicle with the supply of power. SOLUTION: A normally closed switch 42 detects the insertion of a key into a key cylinder and a power input circuit 23 supplies power from a battery 41 to an exciting circuit 21 and an output circuit 22 in response to the detection. Both the circuits 21 and 22 start operation with the supply of the power and a yaw exciting circuit 21 starts the excitation of a vibrator 11 of a yaw rate sensor 10 in the direction of the X axis while the output circuit 22 outputs a voltage signal indicating vibration in the direction of the Y axis picked up to an electronic control unit 30, which provides sufficient time to the starting of a vehicle from the insertion of the key into the key cylinder. Thus, the electronic control unit 30 works to stabilize the vibration of the vibrator 11 and to determine a zero point drift voltage and thereafter, the zero point drift voltage can be used to detect a yaw rate with higher accuracy during the running of the vehicle.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle behavior detection device for starting vehicle behavior detection by supplying electric power.

[0002]

2. Description of the Related Art Conventionally, it has been well practiced to detect the behavior of a vehicle and control the traveling state of the vehicle in accordance with the detected behavior. Some of the detection devices that detect the behavior of the vehicle require time from the start of power supply until the detection output stabilizes, or the zero-point drift amount due to changes in the environment must be taken into consideration. . Therefore, as disclosed in, for example, Japanese Patent Application Laid-Open No. 4-295714, in a vehicle behavior detection device configured to detect a yaw rate as a vehicle behavior, the change state of the zero point drift amount after the start of power supply is changed. Is measured over time, and the measured value is stored as a correction value in a memory in advance, and in actual use, the detection signal is corrected according to the elapsed time from the power supply using the correction value. I am trying.

[0003]

However, the above-mentioned conventional device requires a memory for storing in advance a correction value representing the change state of the zero point drift amount from the start of power supply, and It is necessary to make corrections over time using the correction values. On the other hand, immediately after the start of the engine and while the vehicle speed is zero, the zero point drift amount is measured, and each measured value when the vehicle is traveling is corrected using the zero point drift amount. Can also be considered. However, in this case, if the vehicle is started immediately after the start of the engine, the zero point drift amount measurement accuracy may be low, and the yaw rate detection accuracy, which is the behavior when the vehicle is running, may deteriorate.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a vehicle behavior detecting device for starting the detection of the vehicle behavior by supplying electric power when the vehicle is running. The purpose is to be able to detect the behavior of in a high precision.

[0005]

In order to achieve the above object, a structural feature of the present invention is to detect a vehicle start preparation operation before engine start such as insertion of a key into a key cylinder and closing of a driver's seat door. The operation detecting means and the power input means for starting the input of electric power in response to the detection of the vehicle start preparation operation are provided in the vehicle behavior detecting device.

[0006]

According to the present invention, the behavior detecting device of the vehicle is supplied with electric power in response to the preparatory operation for starting the vehicle before the engine is started, and the behavior detecting device starts its operation. It is possible to secure sufficient time from the start of the vehicle to the start of the vehicle. Therefore, it takes time for the detection output from the start of power supply to stabilize, and even in a vehicle behavior detection device that requires detection of the zero point drift amount due to environmental changes, the detection output is stable before starting the vehicle. Alternatively, since the accurate measurement of the zero point drift amount is completed, the behavior detection accuracy of the vehicle during traveling becomes good with a simple configuration.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 schematically shows a yaw rate detecting device as a vehicle behavior detecting device and peripheral circuits thereof. The yaw rate detection device includes a yaw rate sensor 10 and a yaw rate sensor unit 2 mounted on a vehicle.
0 and electronic control unit 30.

The yaw rate sensor 10 has a vibrating body 11 fixed to the vehicle body. The vibrating body 11 has piezoelectric elements 12 and 12 for excitation and piezoelectric elements 13 and 13 for vibration detection attached thereto. The piezoelectric elements 12 and 12 excite the vibrating body 11 in the X-axis direction, which is one direction in a plane orthogonal to the vertical axis Z. The piezoelectric elements 13 and 13 pick up vibration (Coriolis force) of the vibrating body 11 in the Y-axis direction that is in the plane and perpendicular to the X-axis direction, and output the picked-up signal.

The yaw rate sensor unit 20 includes an excitation circuit 21 and an output circuit 22. Excitation circuit 21
Is composed of an oscillator, an amplifier, etc., and outputs an excitation signal of a predetermined frequency to the piezoelectric elements 12, 12. The output circuit 22 is
It consists of an amplifier, a filter circuit, etc.
The signal from 3 is amplified, filtered, and output. A power input circuit 23 including a resistor, a transistor, and a diode is connected to the excitation circuit 21 and the output circuit 22. The power input circuit 23 is connected to the battery 41 and also to the normally closed switch 42, and shuts off the power supply from the battery 41 to the excitation circuit 21 and the output circuit 22 when the switch 42 is in the ON state. The power supply is allowed when the switch 42 is off.

The normally-closed switch 42 detects a start preparation operation of the vehicle before the engine is started. The normally-closed switch 42 is in an on state when the key is not inserted, is turned off by inserting the key, and is kept off until the key is pulled out. maintain. On the other hand, the ignition switch 43 is turned on with the key inserted and rotated, and the switch 43 is an engine start control circuit (not shown) for starting the engine with the electric power from the battery 41 in the on state. Supply to. The normally closed switch 42 is also connected to a power input circuit 51 in the tilt and telescopic control unit 50 for controlling the tilt operation and the telescopic operation of the steering wheel. This power input circuit 51 is also connected to the battery 41 and functions similarly to the power input circuit 23 in the yaw rate sensor unit 20. When the normally closed switch 42 is in the on state, the tilt and telescopic control unit is operated from the battery 41. Switch off the power supply to 50
When 2 is in the off state, it allows the power supply.

The electronic control unit 30 includes an A / D converter,
It is composed of a microcomputer. The electric power from the battery 41 is constantly supplied to the electronic control unit 30, and the unit 30 waits until the signal from the output circuit 22 becomes stable and determines the zero-point drift voltage. While continuing to detect the corrected yaw rate, the traveling state of the vehicle is controlled using the detected yaw rate.

Next, the operation of the embodiment configured as described above will be described. When the key is not inserted in the key cylinder, the power input circuits 23 and 51 are in the off state, and the power from the battery 41 is the other circuits in the yaw rate sensor unit 20 and the tilt and telescopic control unit 50. Not supplied to both units 2
0,50 does not work.

In this state, when the driver inserts a key into the key cylinder as a starting preparation operation for the vehicle, the normally closed switch 42 is turned off and the power input circuits 23, 51 are turned on.
As a result, electric power starts to be supplied from the battery 41 to the yaw rate sensor unit 20 and the other circuits in the tilt and telescopic control unit 50. In the yaw rate sensor unit 20, the excitation circuit 21 starts operating and starts supplying the excitation signal of a predetermined frequency to the piezoelectric elements 12 and 12, so that the vibrating body 11 starts to vibrate in the X-axis direction at a predetermined frequency. Since the vehicle is stopped in this state, the yaw rate should be zero, and the piezoelectric element 1
The voltage picked up by 3 and 13 is also output circuit 2
The voltage output from 2 should also be zero. However, in reality, the output circuit 22 outputs a non-zero voltage signal as shown in FIG. 2 due to unstable vibration of the vibrating body 11 and environment such as ambient temperature. In this case, the voltage signal that fluctuates from the insertion of the key is based on the unstable vibration of the vibrating body 11, and the stable voltage thereafter is the zero-point drift voltage.

Further, each circuit in the tilt and telescopic control unit 50 also operates to start controlling the tilt operation and the telescopic operation of the steering wheel, but since these operations are not directly related to the present invention, detailed description thereof will be omitted. To do.

When the voltage signal from the output circuit 22 is supplied to the electronic control unit 30, since the unit 30 is constantly operating, a process using the voltage signal is executed by a program process (not shown). In this process,
The electronic control unit 30 waits for a predetermined time T1 (for example, 1 second) until the voltage signal from the output circuit 22 stabilizes, and then calculates the average of the voltage signals for a predetermined time T2 (for example, 1 second) to calculate the same. The average value is stored as the zero point drift voltage. After that, the electronic control unit 30 operates the output circuit 2
The voltage signal from 2 is corrected by the zero point drift voltage, and the yaw rate generated in the vehicle is continuously detected.

On the other hand, when the key is rotated in this state to turn on the ignition switch 43, electric power from the battery 41 is supplied to an engine start control circuit (not shown) via the switch 43, and the control circuit operates. Start the engine. After that, the driver starts the vehicle and the vehicle shifts to a normal traveling state. When the vehicle turns and the yaw rate is generated in the vehicle, the electronic control unit 30 calculates the yaw rate by correcting the voltage signal from the output circuit 22 with the stored zero point drift voltage as described above. The traveling state of the vehicle is controlled based on the calculated yaw rate.

As can be understood from the above description, according to the above embodiment, the yaw rate sensor is activated before the ignition switch 43 is turned on and the engine is started and the key is inserted into the key cylinder. The vibration of the yaw rate sensor 10 becomes stable and the zero point drift voltage is determined in a short time thereafter, and the zero point drift voltage is used to correct the detected yaw rate when the vehicle is running. As a result, before the vehicle starts, a sufficient time for the preparatory operation required for yaw rate detection during traveling of the vehicle is secured, and the yaw rate measurement accuracy during traveling of the vehicle is improved with a simple configuration.

In the above embodiment, the insertion of the key into the key cylinder is detected as a preparatory operation for starting the vehicle before the engine is started.
The vehicle start preparation operation may be detected by detecting the closing of the driver's seat door.

In the above embodiment, the yaw rate is detected as the behavior of the vehicle and the present invention is applied to the yaw rate detecting device. However, the present invention is not limited to the longitudinal acceleration, the lateral acceleration, and the slip of the vehicle. The present invention is applicable to other behavior detection devices as long as it is a device that detects a behavior of a vehicle such as a corner when the vehicle is running, and the detection operation is started by supply of electric power.

[Brief description of drawings]

FIG. 1 is a block diagram schematically showing a yaw rate detecting device and peripheral circuits thereof.

FIG. 2 is a signal waveform diagram output from the output circuit of FIG.

[Explanation of symbols]

10 ... Yaw rate sensor, 11, 12 ... Piezoelectric element, 20
... Yaw rate sensor unit, 21 ... Excitation circuit, 22
... output circuit, 23 ... power input circuit, 30 ... electronic control unit, 41 ... battery, 42 ... normally closed switch, 43 ... ignition switch, 50 ... tilt and telescopic control unit, 51 ... power supply input circuit.

Claims (1)

[Claims] 1. A vehicle behavior detection device for starting vehicle behavior detection by supplying electric power, and an operation detection means for detecting a vehicle start preparation operation before engine start, and a response to the detection of the vehicle start preparation operation. And a power input means for starting the input of power.