JPH089319B2 - Anti-skidding control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Outline] In an anti-skid control device that calculates a vehicle body speed using an acceleration sensor (hereinafter referred to as a G sensor), when the vehicle body acceleration exceeds a positive reference value during braking, the vehicle body stops. To determine.

[Industrial application field]

The present invention relates to an antiskid control device using a G sensor.

[Prior Art] An anti-skid control device that detects a wheel lock from a difference between a vehicle speed and a wheel speed and adjusts a brake hydraulic pressure determines the vehicle speed by various methods. For example, there is a method of estimating and calculating the vehicle body speed from the output of the wheel speed sensor, and a method of directly calculating the vehicle body speed from the output of the ground speed sensor. Moreover, in the anti-skid control device using the G sensor, the stop SW (brake
The vehicle body speed during braking is obtained by integrating the vehicle body G after the switch SW is turned on and subtracting that value (corresponding to the change in speed) from the vehicle speed immediately before the stop switch is turned on.
The G sensor used is constructed as shown in FIG. 3, for example, and generates a positive or negative output voltage depending on the direction of acceleration.
The G sensor shown in the figure is called a servo type, and a displacement detector detects a deviation from the center position of a swingable movable pendulum with a coil for a torquer fixed, and a current corresponding to the deviation is coiled from a servo amplifier. Through the read resistance R _L. The detection current is passed through the resistor R _L to generate the output voltage, while the detection current is passed through the coil to return the pendulum to the center position by the torque of the torquer. There are various other methods for the G sensor.

It is also necessary for the anti-skid controller to know when the vehicle is stopped. This is to prevent the anti-skid control from reaching after the vehicle stops. Conventionally stop SW
When the integrated value of the vehicle body G after turning on becomes equal to the vehicle speed immediately before turning on the SW, in other words, when the current vehicle speed calculated as the difference between the two becomes 0 Km / h, it is determined that the vehicle is stopped. . However, this is a calculation and may differ from the actual vehicle stop time.

[Problems to be solved by the invention]

If the vehicle body stop determination timing based on the vehicle body speed calculation described above lags behind the actual vehicle body stop timing, the anti-skid control device determines that the vehicle body has not stopped yet and continues control, and if a sudden drop in wheel speed due to vehicle body stop is detected, The brake is loosely controlled.

The present invention aims to detect the vehicle stop time more appropriately than the integration method by capturing the rolling back phenomenon of the vehicle that occurs when the vehicle stops.

[Means for solving problems]

FIG. 1 is a basic configuration diagram showing the principle of the present invention. 1 is a G sensor for detecting a vehicle body G, 2 is a switch for passing its output only during a braking period, and 3 is a comparison for comparing the vehicle body G with a positive reference G. It is a vessel.

[Action]

The output of the G sensor 1 is a voltage having a polarity proportional to the size of the vehicle body G and corresponding to the direction of G as shown in FIG. When the vehicle body G being braked is observed by the G sensor 1, a negative G is always detected until the vehicle body stops as shown in FIG. On the other hand, immediately after the vehicle stops, the suspension mechanism causes the vehicle to swing back. This is a vibration phenomenon in which braking is applied so as to stop the rotation of the wheels on the lower part of the vehicle body, so that the passenger compartment and the like on the upper part of the vehicle body go too far in the traveling direction due to inertia and return in the opposite direction due to the reaction. When such swinging back (usually about 1 second) occurs, a portion of the vehicle body G going from negative to positive appears temporarily.

In other words, when it is detected that the vehicle body G is inverted from negative to positive, it is determined that the vehicle body is stopped and it does not matter. The comparator 3 is for this purpose and uses a positive value for the reference G.

〔Example〕

FIGS. 4 to 6 are flowcharts for realizing the configuration of FIG. 1 by software. The steps in FIG. 4 correspond to the switch 2 in FIG. 1, and the steps correspond to the comparator 3. DVS is the vehicle body G, KG1 is the reference G (for example, 0.
1G). When the step becomes DVS> KG1, the vehicle speed VS
Is a process of setting the vehicle speed to 0 by integrating the vehicle body G.
This corresponds to resetting the integrator for calculating VS with the vehicle body stop detection signal output from the comparator 3 in FIG. When the vehicle speed VS becomes 0, the anti-skid control device ends the control, so if the brake hydraulic pressure is being reduced, it is returned to the original state and the wheel is locked.

In the example of FIG. 5, a step is added between the step and the vehicle body stop detection of the step is performed only when the vehicle body speed VS is a constant value KV1. This is a fail-safe function that prevents the vehicle body from being mistakenly stopped due to braking when the vehicle is not intended to stop.

In the example of FIG. 6, the value of the reference value KG1 is switched according to the road surface condition. The friction coefficient (μ) of the road surface is judged in the step, and if it is a high μ road, the high μ reference value KGHi is set in the step. If it is a low μ road, the low μ reference value KGLo is introduced in steps. On a high μ road where KGHi> KGLo and the braking effect is high, the reference value KG1 is increased. This is because a high μ road appears locally during braking on a low μ road, and a temporary acceleration state when entering the low μ road is not mistakenly considered as a vehicle stop.

Obviously, the steps of FIG. 5 may be inserted after the steps of FIG.

〔The invention's effect〕

As described above, according to the present invention, it is possible to properly determine the vehicle body stop timing in the anti-skid control device using the G sensor.

[Brief description of drawings]

FIG. 1 is a basic configuration diagram of the present invention, FIG. 2 is an operation explanatory diagram of the present invention, FIG. 3 is an explanatory diagram of an acceleration sensor, and FIGS. 4 to 6 are flowcharts showing different embodiments of the present invention. is there.

Claims (1)

[Claims] 1. An anti-skid control device comprising means for detecting a vehicle body acceleration during braking by an acceleration sensor, and determining that the vehicle body is stopped when the acceleration exceeds a negative to positive reference value.