JPH05112233A - Brake control method - Google Patents

Abstract

PURPOSE:To enhance the accuracy of callipers pressure in a brake control including anti-lock control by correcting the torque constant of an actuator with the temp. prior to anti-lock, calculating the torque, and by calculating the braking force from this torque and the sensed position of an expander piston. CONSTITUTION:A control unit 72 is equipped with a function to correct the torque constant of a DC motor 24 in compliance with the temp. change in the DC motor itself and a function to calculate the callipers pressure (braking pressure) on the basis of the motor torque acquired from the terminal amperage of the motor 24 and the corrected torque constant and the position of an expander piston 46. A wheel speed sensor 76 is connected with a disc plate 66. In this constitution, the motor current is measured, motor coil temp. is calculated, and torque constant is determined. The actuator torque is determined from this torque constant, and callipers pressure is calculated from the sensed position of the expander piston 46, and a drive signal is given to a motor controller 70.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake control for performing antilock control by calculating a braking force from the position of an expander piston which constitutes an antilock modulator and the torque of an actuator which drives this expander piston. Regarding the method.

[0002]

2. Description of the Related Art For example, in automobiles and motorcycles, a brake control device is used to perform antilock control of a brake.

This brake control device calculates a slip ratio between a wheel and a road surface from the speed of a running vehicle and the rotational speed of a wheel, and based on the calculated slip ratio, an optimum braking force (caliper) for the vehicle body is calculated. It is known that pressure is calculated to perform antilock control.

In this case, the slip ratio between the wheel and the road surface and the friction coefficient (μ) in the rotational direction of the wheel and in the lateral direction orthogonal to this rotational direction generally have the relationships shown in FIGS. 7 and 8. This characteristic is called a μ-S curve, and on a road surface with a low friction coefficient (hereinafter referred to as a low μ road) such as ice burn, a road surface with a high friction coefficient such as an asphalt road surface (hereinafter referred to as a high μ road). Compared with, the value of μ also decreases for the same slip ratio.

On the other hand, the lock speed and the return speed of the wheel with respect to the caliper pressure also greatly vary depending on the road surface μ, and on the high μ road, the lock speed is slow and the return speed is fast, while on the low μ road. , The return speed is slow and the lock speed is fast.

Therefore, it is considered to estimate and control μ from the actual deceleration of the vehicle body, the wheel speed, and the like.

[0007]

However, in the above method, there is a possibility that the value of μ varies considerably due to, for example, a change in the braking state due to braking of the front wheels and / or the rear wheels. Therefore, in order to estimate μ more accurately, it is possible to directly measure the caliper pressure, but an expensive and heavy hydraulic pressure sensor is required, and there is a problem in manufacturing cost and weight. Not used conventionally.

The present invention solves this kind of problem and provides a brake control method capable of highly accurately calculating caliper pressure with a simple structure without the need for using a dedicated sensor or the like. The purpose is to

[0009]

In order to achieve the above object, the present invention performs antilock control by driving an expander piston which constitutes an antilock modulator by an actuator to control the braking force of a wheel. A brake control method, which comprises:
A step of correcting the torque constant of the actuator in response to a temperature change; a step of calculating the torque of the actuator based on the corrected torque constant; a step of detecting the position of the expander piston; And a step of calculating the braking force of the wheel from the position of the panda piston and the calculated torque of the actuator at this position.

[0010]

In the brake control method according to the present invention, since the torque constant of the actuator is constantly corrected in accordance with the temperature change, the accurate torque constant can be obtained based on the corrected torque constant without being affected by the change in the operating temperature. The torque can be calculated. Therefore, the braking force can always be calculated with high accuracy from the torque and the position of the expander piston, and optimal brake control can be performed even in a cold region or a severe heat region.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The brake control method according to the present invention will be described in detail below with reference to the accompanying drawings in connection with an embodiment for implementing the same.

In FIG. 2, reference numeral 10 indicates a motorcycle, which has a main body portion 12, a handle portion 14, a front wheel portion 16 and a rear wheel portion 18.

A brake control device 20 for implementing the brake control method according to the present embodiment on the motorcycle 10.
As shown in FIG. 1, the brake control device 20 includes an antilock modulator 22, a DC motor 24 constituting the modulator 22 has a pinion 26 attached thereto, and the pinion 26 has a gear. 28 meshes. The gear 28 is axially supported by the crankshaft 30,
One end of a crank pin 34 is eccentrically connected to the crank shaft 30 via a crank arm 32. At the other end of the crank pin 34, a crank arm 36
A potentiometer 38 for detecting the position of an expander piston (described later) is attached via the.

A cam bearing 4 is attached to the crank pin 34.
0 is rotatably mounted, and the lower end side of the cam bearing 40 is constantly pressed toward the upper limit position under the action of the return spring 44 accommodated in the spring accommodating portion 42. An expander piston 46 abuts on the upper end side of the cam bearing 40, and the expander piston 46 is vertically displaced as the cam bearing 40 moves up and down to open and close the cut valve 48.

Above the expander piston 46,
A cut valve housing 50 having a built-in cut valve 48 is provided, and the cut valve housing 50 has an input port 5
A master cylinder 56 is connected to 2 via a passage 54, while a wheel braking caliper cylinder 62 is connected to an output port 58 of the cut valve housing 50 via a passage 60. The master cylinder 56 and the caliper cylinder 62 are provided with a passage 54, a modulator 22 and a passage 60.
Are connected to each other via and the hydraulic oil is filled in this path. The master cylinder 56 adjusts hydraulic pressure under the action of the brake lever 64, drives the caliper cylinder 62 via the cut valve 48, and operates the front wheel unit 1.
A braking force is applied to the disc plate 66 disposed on the rear wheel portion 6 and / or the rear wheel portion 18.

Potentiometer 38 and DC motor 2
A motor controller 70 is connected to 4. The motor controller 70 includes a forward / reverse control circuit 71 for rotating the direct-current motor 24 in the forward and reverse directions, and also provides angle information of the crank pin 34 from the potentiometer 38, that is, the position of the expander piston 46 and the terminal of the direct-current motor 24. And the current value are supplied to the control unit 72.

The control unit 72 obtains the function of correcting the torque constant of the DC motor 24 in response to the temperature change of the DC motor 24 itself, the terminal current value of the DC motor 24 and the corrected torque constant. And a function of calculating a caliper pressure (braking force) based on the motor torque and the position of the expander piston 46. The control unit 72 is connected to a wheel speed detection sensor 76 mounted on the disc plate 66. Has been done.

Next, the operation of the brake control device 20 thus constructed will be described in connection with the brake control method according to this embodiment.

During normal braking, the return spring 44
The crank pin 34 is held at a preset upper limit position by the resilience of the cam bearing 40, and the cam bearing 40 mounted on the crank pin 34 is maintained with the expander piston 46 pushed up. As a result, the cut valve 48 is pushed up by the expander piston 46, and the input port 52 and the output port 58 are in communication.

Then, the master cylinder 56 is urged by gripping the brake lever 64, and the brake hydraulic pressure generated by the master cylinder 56 is passed through the passage 5
4, the force is transmitted to the caliper cylinder 62 via the input port 52, the output port 58, and the passage 60, and the braking force is applied to the disc plate 66.

On the other hand, during normal traveling (or when the vehicle is stopped with the ignition activated), the control unit 72 controls the forward / reverse control circuit 7 of the motor controller 70.
1, a drive signal is supplied to the DC motor 24, and a constant voltage is applied to the DC motor 24 at constant time intervals and for a constant time. As shown in FIG. 3, the voltage applied to the DC motor 24 has a polarity (-voltage) opposite to the direction in which the crank pin 34 is biased toward the upper limit position, that is, the pressure reducing direction (+ voltage). is doing.

As a result, a motor current is obtained from the DC motor 24, and this motor current is as shown in FIG.
The temperature decreases as the temperature of the DC motor 24 itself increases. That is, the coil resistance value R and the temperature change ΔT at room temperature
The coil resistance value R'when there is a relation has the relationship of the following equation (1).

R ′ = R (1 + ΔT · k / 100) (1) where k is the resistance change rate (% / ° C.), and the motor current is measured to calculate the coil resistance value R ′. ) Is used to calculate the temperature of the motor coil of the DC motor 24. Furthermore, the motor torque constant K corresponding to this change in the motor coil temperature
T is corrected using the following equation (2) to obtain the motor torque constant KT '.

KT ′ = KT (1−ΔT · a / 100) (2) where a: Demagnetization rate (% / ° C.) Next, a drive signal is sent from the control unit 72 to the motor controller 70 to perform antilock control. When supplied, the rotation direction and rotation amount of the DC motor 24 are controlled. Therefore, the pinion 26 rotatably attached to the rotating shaft (not shown) is rotated to rotate the gear 28 meshing with the pinion 26 and the crank arm 32 fixed to the gear 28 via the crank shaft 30. The crank pin 34 attached to 32 is displaced from the upper limit position toward the lower limit position. The cam bearing 40 descends due to the deviation of the crank pin 34, and the brake oil pressure acting on the expander piston 46 is applied to the DC motor 24.
The expander piston 46 presses the cam bearing 40 and quickly descends because the expander piston 46 works to be added to the torque.

When the expander piston 46 descends by a predetermined amount, the cut valve 48 is seated, which disconnects the input port 52 and the output port 58. Therefore, when the expander piston 46 is further lowered by itself, the volume on the output port 58 side increases and the hydraulic pressure applied to the caliper cylinder 62 decreases.
The braking force of is reduced.

Here, the position of the expander piston 46 is detected as a crank angle via the potentiometer 38 by the deviation of the crank pin 34, and the output value of this potentiometer 38 is introduced into the motor controller 70. Then, the output value and the terminal current value of the DC motor 24 are supplied from the motor controller 70 to the control unit 72. In the control unit 72, the motor torque (TM) of the DC motor 24 is first calculated from the terminal current value according to the following equations,
Further, the caliper pressure (PC) is calculated.

TM = KT ′ · (IM-IO) (3) TP = (Z · J · JM + JC) · ω−TM + TS ± TF (4) PC = 4 · TP / (π · D · D · e -Sin θc) (5) TM: Motor torque KT ': Corrected motor torque constant IM: Motor current IO: Motor no-load current TP: Caliper pressure torque Z: Reduction ratio JM: Motor inertia mass JC: Crank inertia mass ω : Crank angular acceleration TS: B / USPG torque TF: Friction torque D: Expander piston diameter e: Crank eccentricity θc: Crank angle In this case, in this embodiment, the motor current value of the DC motor 24 is detected. A change in the motor coil temperature of the DC motor 24 is detected, and the motor torque is corrected in accordance with the temperature change using the equation (2). Constant KT 'is produced. Then, the motor torque TM is calculated based on the corrected motor torque constant KT ', and the caliper pressure (PC) is calculated based on the result.
Therefore, even when the environmental conditions change to about -20 ° C to 100 ° C as in the case of actually using it in a cold area or a severely hot area, it is not affected by this and is always highly accurate. The effect that the caliper pressure is calculated is obtained. This makes it possible to perform optimum antilock control.

That is, as shown in FIG. 5 and FIG.
When the temperature of the motor coil of the DC motor 24 becomes high, the motor torque constant TK 'is corrected to be larger than the motor torque constant TK at room temperature. The result was obtained that the caliper pressure close to the caliper pressure can be calculated and estimated.

Further, in FIG. 4, if the range of the current value corresponding to the actually used temperature range is set in advance (see the shaded area in the figure), disconnection occurs when no current flows when voltage is applied. On the other hand, it is detected that there is a short circuit when a current exceeding this current value range flows when a voltage is applied. Therefore, there is an effect that a defect of the DC motor 24 can be detected easily and accurately.

In this embodiment, the disc plate 6
The case where the caliper pressure of the caliper cylinder 62 that applies the braking force to 6 is calculated has been described, but it is also possible to cope with the braking of the drum brake. At this time, there is a brake shoe that is pressed against the drum brake as the one corresponding to the caliper cylinder 62, and the caliper pressure (PC) corresponding to the opening of the brake shoe is calculated from the crank angle and the terminal current value.

Further, in the above embodiment, the front wheel portion 1
Although the case of 6 has been described as an example, the same can be applied to the case of the rear wheel portion 18.

[0032]

In the brake control method according to the present invention, since the torque constant of the actuator is corrected in accordance with the temperature change before the antilock control, the change in the operating temperature of the actuator itself is not affected. Accurate torque can be calculated based on the corrected torque constant. Therefore, it is possible to always calculate a highly accurate braking force from the torque and the position of the expander piston, and optimal antilock control is performed even in a cold region or a severe heat region.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an apparatus for implementing a brake control method of the present invention.

FIG. 2 is a schematic external view of a motorcycle incorporating the brake control device.

FIG. 3 is an explanatory diagram when a voltage is applied to a DC motor.

FIG. 4 is an explanatory diagram of a current value obtained by applying the voltage.

FIG. 5 is a relationship diagram between each torque and current calculated from a motor torque constant at room temperature and a corrected motor torque constant at high temperature.

FIG. 6 is a relationship diagram between each caliper pressure and the measured caliper pressure depending on whether or not the motor torque constant is corrected.

FIG. 7 is a relational diagram between a friction coefficient in a rotational direction of a wheel and a slip ratio.

FIG. 8 is a relationship diagram between a lateral friction coefficient of a wheel and a slip ratio.

[Explanation of Codes] 20 ... Brake Control Device 22 ... Modulator 24 ... DC Motor 34 ... Crank Pin 38 ... Potentiometer 46 ... Expander Piston 56 ... Master Cylinder 62 ... Caliper Cylinder 70 ... Motor Controller 72 ... Control Unit

Claims (3)

[Claims] 1. An expander piston that constitutes an anti-lock modulator is driven by an actuator,
A braking control method for controlling anti-lock control by controlling a braking force of wheels, comprising a step of correcting a torque constant of the actuator in response to a temperature change before the anti-lock control, and the corrected torque constant. Calculating the torque of the actuator based on the above, detecting the position of the expander piston, and calculating the braking force of the wheel from the position of the expander piston and the calculated torque of the actuator at this position. And a brake control method. 2. The brake control method according to claim 1, wherein a constant voltage is applied to the actuator at constant time intervals to detect a current value of the actuator, and a change in the current value is taken as a temperature change to determine a torque constant of the actuator. A brake control method characterized by: 3. The brake control method according to claim 2, wherein when the detected current value of the actuator is outside the preset current value range, the actuator is determined to be defective. Brake control method.