JPH0642898Y2 - Traction control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION << Industrial Application Field >> The present invention relates to a traction control device.

<< Prior Art >> As a conventional traction control device, as shown in FIG. 7, speeds of driving wheels 1 and non-driving wheels 2 are measured by speed sensors 3 and 4, and a control means 5 drives them based on these measurement signals. The speed of the wheel 1, that is, the wheel speed and the speed of the non-driving wheel 2, that is, the vehicle speed are measured, and the slip ratio of the tire is obtained from the difference between these two speeds.

Further, the control means 5 controls the opening degree of the throttle valve 7 of the engine 6 in order to adjust the driving force of the driving wheels 1 so that the vehicle can be effectively accelerated without causing tire slip, and the driving is performed. The brake hydraulic pressure is controlled to adjust the braking force of the wheel 1.

<< Problems to be Solved by the Invention >> In the above-mentioned conventional traction control device, the opening of the throttle valve during traction control is in small increments (see FIG. 6 described later), and the throttle valve control system However, there is a drawback in that the engine speed changes unnecessarily, causing a howling, or feeling acceleration in the front and rear, and further vibrating the vehicle.

<Purpose of Invention> The present invention has been made to solve the above problems, and an object thereof is to provide a traction control device capable of smooth traction control.

<< Means for Solving Problems >> The present invention is configured as shown in FIG. 1 in order to achieve the above-mentioned object, and includes a speed measuring means a for measuring a wheel speed and a vehicle body speed, and a throttle valve opening degree. Adjustable throttle opening operating means b, brake hydraulic pressure operating means c for controlling the brake hydraulic pressure, and a slip state of the drive wheel obtained based on the calculation result from the speed measuring means a. In a traction control device having a control means d for controlling the throttle opening operation means b and the brake hydraulic pressure operation means c so as to suppress the throttle opening characteristic, the throttle opening characteristic is at least the wheel speed and the first derivative of the wheel speed. , Verifies the suitability of each language control law by using the membership function corresponding to the language control law, which is defined by the qualitative language control law corresponding to the slip ratio of the driving wheels and the vehicle speed. A fuzzy inference means e for calculating a throttle opening output from a balance value of a plurality of control rules is provided, and a gain when the throttle is closed by the control means d is such that a first-order differential value of wheel speed is a predetermined value or more, Further, the traction control device is characterized in that the membership function is determined so as to be maximum when the slip ratio of the driving wheels is equal to or less than a predetermined value.

<< Operation >> In the present invention, the wheel speed and the vehicle body speed are measured by the speed measuring means, the opening of the throttle valve can be adjusted by the throttle opening operation means, and the brake oil pressure is controlled by the brake oil pressure operation means. The power is adjustable, and the control means controls the throttle opening operation means and the brake oil pressure operation means so as to suppress the slip state of the drive wheels obtained based on the calculation result from the speed measurement means.

Then, the fuzzy reasoning means determines the throttle opening characteristic by at least a wheel speed, a first-order differential value of the wheel speed, a slip ratio of the driving wheels, and a qualitative language control law corresponding to the vehicle speed, and corresponds to the language control law. The degree of conformity of each language control law is verified using the membership function described above, and the throttle opening output is calculated from the balance value of the plurality of control rules.
In particular, in this invention, the gain when the throttle is closed by the control means is maximized when the first-order differential value of the wheel speed is a predetermined value or more and the slip ratio of the driving wheels is a predetermined value or less. The membership function is defined as follows.

<< Description of Embodiments >> FIG. 2 is a schematic view showing a configuration of an embodiment according to the present invention. It should be noted that the same components as those of the related art will be described with the same reference numerals.

In the figure, 1 is a driving wheel of the vehicle and 2 is a driven wheel, and their respective rotation speeds are detected by speed sensors 3 and 4.

Reference numeral 5 is a control means for inputting signals from the speed sensors 3 and 4 and outputting control signals to a throttle valve and a brake hydraulic actuator described later.

Reference numeral 6 denotes an engine, and the opening of the throttle valve 7 (hereinafter referred to as "throttle opening") is adjusted by a control signal of the control means 5 to adjust the driving force. Further, reference numerals 8 and 9 denote a brake hydraulic actuator for the driving wheel 1 and a brake hydraulic actuator for the non-driving wheel 2, and the hydraulic pressure (hereinafter referred to as "brake hydraulic pressure") is adjusted by a control signal of the control means 5 to increase the braking force. It is supposed to be adjusted.

Reference numeral 10 is a fuzzy inference means, which is a control means 5.
Is a part having a function of determining the operation amount when controlling the throttle valve 7 and the like and having a characteristic configuration of the present invention.

This fuzzy inference describes the control characteristics by a control law in a qualitative language, and verifies the degree of conformity of the control law, the so-called certainty value (CF value) using the membership function corresponding to this control law. In addition, it is a means for determining the final manipulated variable by obtaining the harmony of the CF value of each control law.

FIG. 3 shows each control law and membership function used in the fuzzy control means 10. The control law shown here is made in consideration of the relationship between the traction control and the throttle opening and the relationship between the brake hydraulic pressure and the throttle opening, which have been empirically known in the past, and Verification of membership function corresponding to each control law and
The CF value is created by using a simulation model so that the control can be performed continuously and smoothly and the optimum effect can be realized.

In particular, these membership functions give a large throttle opening change when the throttle opening is limited by the first slip after opening the throttle, and then suppress the throttle opening change sufficiently in harmony with the brake hydraulic pressure. It is configured so as to have the characteristic.

3 (1) to (18), the wheel speeds of the driving wheels, the wheel speeds of the non-driving wheels 2, that is, the vehicle body speeds, the difference between these two wheels, that is, the tire slip ratio and the throttle opening control. The membership functions corresponding to the law and its control law are shown.

In addition, (19) to (22) in FIG.
A control law of the slip ratio and the throttle opening and a membership function corresponding to the control law are shown.

Hereinafter, the process in which the fuzzy reasoning means 10 determines the manipulated variable is shown in FIG. 4 in which the control law (LCR) 1 and LCR 10 are represented, and further in FIG.
A description will be given using a flowchart showing the procedure of the figure.

Now, the vehicle speed Vk and the wheel speed Vωk at time k are measured by the speed sensors 3 and 4 (step 100). From each speed described above, the slip ratio λk at that time, the first-order differential values ΔVk, ΔVωk and the second-order differential values Δ ² Vk, Δ ^{2 of} each speed
Vωk is calculated (step 102), and the probability value (CF value) is calculated in the next step 104 based on these values.
This method is to find the above measured value on the horizontal axis of the membership function of the antecedent of each membership, draw a vertical line from this point, and draw a horizontal line from the point intersecting the membership diagram. Obtain the CF value from the point where the horizontal line intersects the vertical axis.

This is explained by applying it to LCR1 in FIG. 4 (1). If ΔVωk is calculated on the horizontal axis of the membership of the antecedent proposition, the CF value of ψ ₁ is obtained on the vertical axis. That is, it shows the degree to which the ψ _{1 of} this CF value satisfies the antecedent proposition.

Next, the membership function of the consequent proposition is clamped by the CF value of the antecedent proposition (step 106). That is, C in LCR1
Clamping the membership function of the consequential proposition with the F value of ψ ₁ , we get the membership function with the shape shown on the right. This is a candidate for the operation of LCR1, that is, the operation of the throttle opening.

In the same way as above, also in LCR10 in FIG. 4 (2), if ΔVωk and ΔVk are obtained in the membership function of the antecedent proposition, CF values of ψ ₂ and ψ ₃ are obtained. Of these, when the CF value is lower, that is, when the membership of the consequential proposition is clamped by ψ ₂ , the membership function shown on the right is obtained, which is LC
It becomes a candidate for the operation of R10. Clamping with a low CF value is to prioritize safety.

When the clamped membership function of each control law is obtained as described above, the harmony of these is obtained and the final manipulated variable is determined (step 108).

As a method for obtaining this harmony, there is a weighted average method or a centroid method, and FIG. 4 (3) shows an example of finding the harmony by the centroid method. Here, in order to simplify the description, a case where three clamped membership functions are shown is shown, and the centers of gravity of these areas (hatched portions) are determined, and this center of gravity position is the final position. Is determined as a proper operation amount (step 110).

The control means 5 is based on the operation amount determined as described above.
Is output so as to control the throttle valve 7 and the brake hydraulic actuator 8.

According to the above-mentioned embodiment, the fuzzy inference using the membership function is used as the operation amount for the throttle opening adjustment and the brake hydraulic pressure adjustment, and the membership opening is limited by the first slip after opening the throttle. When changing the throttle opening, a large change in throttle opening is applied, and after that, the characteristic is that the change in throttle opening is suppressed in harmony with the brake oil pressure. The advantage is that smooth traction control is possible.

FIG. 6 is a control characteristic diagram showing the relationship among the slip ratio during acceleration, vehicle speed, brake oil pressure, throttle opening and accelerator pedal opening of the present invention. For comparison, the change in throttle opening in the conventional control device is also shown.

As is clear from this figure, the change in throttle opening in this embodiment is much smoother than in the prior art.

<Effect> As described above, according to the present invention, the fuzzy inference means determines the throttle opening characteristic to be a qualitative language control law corresponding to at least the wheel speed, the first derivative of the wheel speed, the slip ratio of the driving wheel, and the vehicle speed. According to the present invention, the membership function corresponding to the language control law is used to verify the degree of conformity of each language control law, and the throttle opening output is calculated from the balance value of the plurality of control rules. Then, the gain when closing the throttle by the control means,
When the first derivative value of the wheel speed is equal to or higher than a predetermined value and the slip ratio of the driving wheels is equal to or lower than the predetermined value, the membership function is determined so as to be maximized. Despite being small, since the wheel acceleration is large, the throttle opening can be closed with a high gain, and excessive traction can be quickly reduced. Since the opening and closing of the throttle opening is performed with a gain, vibration of the vehicle body due to sudden opening and closing control of the throttle opening can be suppressed, and smooth traction control can be performed. Further, the control of the throttle opening / closing gain can be achieved only by defining the membership function as described above by the fuzzy inference means without performing strict tuning such as tuning of the non-linear gain or tuning of the filter.

[Brief description of drawings]

FIG. 1 is a claim correspondence diagram, FIG. 2 is a schematic diagram showing the configuration of the present invention, FIG. 3 is an explanatory diagram showing a control law and a membership function, and FIG. 4 is a membership for explaining an operation amount. FIG. 5 is an explanatory diagram showing a function, FIG. 5 is a flowchart showing a procedure for determining the manipulated variable, FIG. 6 is a control characteristic diagram, and FIG. 7 is a schematic diagram showing a configuration of conventional traction control. a: speed measuring means b: throttle opening operation means c: brake hydraulic pressure operation means d: control means e: fuzzy reasoning means

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location F02D 45/00 312 M 7536-3G 370 B 7536-3G

Claims (1)

[Scope of utility model registration request] 1. A speed measuring means for measuring a wheel speed and a vehicle body speed, a throttle opening operation means for adjusting an opening of a throttle valve, and a brake oil pressure operation for controlling a brake oil pressure to adjust a braking force. And a control means for controlling the throttle opening operation means and the brake hydraulic pressure operation means so as to suppress the slip state of the drive wheels obtained based on the calculation result from the speed measurement means. , The throttle opening characteristic is determined by a qualitative language control law corresponding to at least the wheel speed, the first-order differential value of the wheel speed, the slip ratio of the driving wheel, and the vehicle speed, and the membership function corresponding to the language control law is used. The fuzzy inference means for verifying the degree of conformity of each language control law and calculating the throttle opening output from the balance value of a plurality of control rules, The membership function is determined so that the gain at the time of closing the throttle by the control means is maximized when the first-order differential value of the wheel speed is a predetermined value or more and the slip ratio of the driving wheels is a predetermined value or less. A traction control device characterized in that