JPH0796823A - Vehicular controller - Google Patents

Abstract

PURPOSE:To improve the control precision of a vehicular controller by assuming the rotary speed of a belt side part considering the relative revolution between the rim side part and the belt side part of a wheel with a tyre and carrying out an anti-lock control based thereon. CONSTITUTION:A rim side part angular speed is detected by an electro-magnetic pickup 12, etc., and a belt side part angular speed and the real radius of a tyre are assumed by a computer 47, constituting a disturbance observer based on the detection value, rim side part inertia moment, belt side part inertia moment and twist spring constant. Further, a belt side part rotary speed is calculated by a controller 144 as a product of the assumed belt side part angular speed and the real radius and anti-lock control is carried out through electro- magnetic valves 122, 132 based on that value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for controlling the motion of a vehicle by using the rotational speed of a wheel with a tire (hereinafter also referred to as a wheel) of the vehicle, and more particularly to improving the control accuracy thereof. Is.

[0002]

2. Description of the Related Art For example, the following devices are already known as devices for controlling the motion of a vehicle using the rotational speed of wheels.
As described in Japanese Patent Laid-Open No. 56-34551, it is an anti-lock control device that prevents the braking wheels from excessively slipping when the vehicle is braked, or the driving wheels have excessive slipping when the vehicle is driven. A traction control device that prevents the generation of the drive torque, and a drive torque distribution control that controls the distribution ratio of the drive torque to the front and rear wheels so that the drive torque of the vehicle engine is effectively transmitted to the front and rear wheels respectively. It is a device.

The rotational speed of the wheel should essentially match the rotational speed at the belt side of the wheel with tire, that is, the peripheral speed of the contact portion. However, it is relatively difficult to directly detect the belt side rotation speed itself. On the other hand, it is relatively easy to directly detect the rim side angular velocity itself. Therefore, conventionally, both the assumption that the rim side portion and the belt side portion of the wheel with a tire always rotate integrally, and the assumption that the radius of the tire, that is, the radius of the belt side portion, is always constant at the same time. The belt side rotation speed is adopted from the rim side angular velocity detected by the sensor and the standard radius of the tire.

However, such an assumption does not always hold. Since the rim side part and the belt side part are connected by an elastic body, the twist between the rim side part and the belt side part may fluctuate. This is because the radius may change.

In addition to the above-mentioned conventional techniques, the following techniques have already been proposed. This is the actual Kaihei 2-4546
As described in Japanese Patent Publication No. 1, it is a technique of estimating the actual radius of the tire and estimating the belt side rotation speed. Specifically, it is assumed that the product of the average value of the rim side angular velocities between all the wheels of the vehicle and the standard radius (fixed value) of the tire in the straight running state of the vehicle matches the true belt side rotational speed. It is estimated that the value divided by the rim side angular velocity of each wheel represents the actual radius of each wheel, and the belt side rotational speed of each wheel is calculated from this actual radius and the rim side angular velocity when the vehicle is not straight. It is a technology to estimate.

On the other hand, the anti-lock control device disclosed in Japanese Patent Laid-Open No. 56-34551 sequentially detects the friction coefficient μ between the tire and the road surface, and the brake pressure of the tire is adjusted so that the detected value becomes as large as possible. It is a form of controlling. Here, the detection of the friction coefficient mu, the equation of motion is established on a wheel during vehicle braking, i.e. carried out with a _{Jω '+ T E + T B} = μ · F Z · R becomes equation. However, J: moment of inertia of wheel ω ': wheel angular acceleration (= time derivative of wheel angular velocity ω) T _E : braking torque by engine brake T _B : braking torque by brake device F _Z : wheel load (= wheel grounding) Load) R: tire radius (= distance between tire rotation axis and ground contact surface)

[0007]

According to the belt side portion rotation speed estimation technique described in the above publication, the deterioration of the estimation accuracy due to the variation of the actual radius of the tire is suppressed. However, since the assumption that the rim side and the belt side always rotate integrally is adopted, when the twist between the rim side and the belt side fluctuates, the belt side rotation speed is changed. It cannot be estimated with sufficient accuracy.

On the other hand, according to the friction coefficient detecting technique described in the later publication, it is assumed that the rim side portion and the belt side portion always rotate integrally, the wheel angular velocity ω is detected, and the wheel angular acceleration is detected. ω ′ is detected, and the assumption that the radius R of the tire is always constant is also adopted, and the friction coefficient μ is detected based on the tire radius R, the wheel angular acceleration ω ′, and the like. That is, the above equation of motion is the equation of motion that holds when the wheels are assumed to be rigid. Therefore, the friction coefficient μ cannot be accurately detected when the twist between the rim side portion and the belt side portion changes or when the actual radius of the tire changes.

In summary, in any of the above-mentioned publications, the assumption that the rim side portion and the belt side portion always rotate integrally is adopted to estimate the belt side rotational speed and detect the friction coefficient. Therefore, the estimation
There is a problem that it is difficult to sufficiently increase the detection accuracy, and it is also difficult to sufficiently increase the vehicle motion control accuracy.

In view of these circumstances, the invention of claim 1 improves the estimation accuracy by estimating the belt side rotation speed in consideration of the relative rotation between the rim side portion and the belt side portion, As a result, the problem is to improve the control accuracy of the vehicle motion.

A second aspect of the present invention is intended to improve the detection accuracy of the friction coefficient between the tire and the road surface by using the belt side rotational speed estimated by the first aspect of the invention. .

[0012]

In order to solve each of the problems, the invention of claim 1 is directed to a vehicle control device as shown in FIG. 1, and (a) detects a rim side angular velocity of a wheel with a tire of a vehicle. Rim side angular velocity detecting means 1, and (b) the detected rim side angular velocity, the rim side moment of inertia of the wheel with the tire, the belt side moment of inertia and the torsion spring between the rim side and the belt side. Belt side rotation speed determining means 2 for estimating the belt side rotation speed of the wheel with the tire based on the constant, and determining the belt rotation speed based on the estimated belt side rotation speed and the tire radius.
And (c) a motion control mechanism 3 for controlling the motion of the vehicle,
(d) A controller 4 that controls the movement of the vehicle via the movement control mechanism 3 based on the determined belt side rotation speed.

The invention of claim 2 further includes (e) a friction coefficient detecting means 5 for detecting a friction coefficient between the tire and a road surface with which the tire is in contact, based on at least the determined belt side rotational speed. Further, the controller 4 controls the movement of the vehicle based on at least the friction coefficient detected by the friction coefficient detecting means 5.

The inventions of the respective claims are applied to a vehicle control device of a type in which the belt side rotation speed is a control target, such as the antilock control device, the traction control device, and the drive torque distribution control device. Of course, the present invention can be applied to a vehicle control device of a type in which the belt side rotation speed is not a control target, such as a rear wheel steering control device. Then, for example, when the invention of claim 1 is applied to the rear wheel steering control device, the friction coefficient of the road surface is estimated based on the time differential value of the belt side rotation speed, and the corresponding influence is applied to the rear wheel steering angle. Can be implemented in a mode in which it is added to the control characteristics (for example, control gain).

[0015]

In the vehicle control device according to the first aspect of the present invention, the rim side angular velocity detecting means 1 detects the rim side angular velocity of the tire-equipped wheel, and the belt side rotational speed determining means 2 detects it. The belt side angular velocity of the wheel with tires is estimated based on the rim side angular velocity, the rim side moment of inertia of the tire-equipped wheel, the belt side inertia moment, and the torsion spring constant between the rim side-belt side. To be done. When it is considered that the wheel with tire has a structure in which the rim side part and the belt side part are connected by a torsion spring, a certain relationship is established between the rim side part, the belt side part and the torsion spring, and that relationship is used. By doing so, the belt side angular velocity is estimated. This relationship will be described in detail in Examples.

In this vehicle control device, the belt side rotation speed determining means 2 further determines the belt side rotation speed based on the estimated belt side angular speed and the tire radius. Here, as the "tire radius", a standard value may be adopted as a fixed value, but it is desirable to estimate the actual radius and adopt that value. And
The controller 4 controls the movement of the vehicle via the movement control mechanism 3 based on the determined belt side rotation speed.

Particularly, in the vehicle control device according to the second aspect of the present invention, at least the
The friction coefficient between the tire and the road surface is detected based on the determined belt side rotation speed, and the controller 4 controls the motion of the vehicle based on at least the detected friction coefficient.

[0018]

Therefore, according to each of the first and second aspects of the present invention, the belt side rotation speed of the tire-equipped wheel is accurately estimated to control the motion of the vehicle, so that the control accuracy is improved. The effect is obtained.

Particularly, according to the invention of claim 2, the tire is
Since the friction coefficient between the road surfaces is accurately estimated to control the movement of the vehicle, it is possible to obtain the effect that the movement of the vehicle is controlled with a characteristic that accurately matches the actual friction coefficient.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An antilock control device will be described in detail with reference to the drawings as an embodiment common to the inventions of claims 1 and 2.

In FIG. 3, reference numeral 110 indicates a brake pedal. This brake pedal 110 is a booster 1
It is linked to the master cylinder 114 via 12. The master cylinder 114 is a tandem type, and generates a pressure having a height corresponding to the pedaling force of the brake pedal 110 in two pressurizing chambers independent of each other. The brake pressure generated in one pressure chamber is transmitted to the wheel cylinder of the left front wheel brake and the wheel cylinder of the right rear wheel brake, respectively, and the brake pressure generated in the other pressure chamber is the wheel wheel of the right front wheel. It is transmitted to the cylinder and the wheel cylinder of the left rear wheel brake. That is, this brake system includes a first brake system for the right front wheel and the left rear wheel and a second brake system for the left front wheel and the right rear wheel.
It is an X piping type with the brake system of. Hereinafter, the first brake system will be described as a representative of the second brake system.
The description of the brake system is omitted.

One pressurizing chamber of the master cylinder 114 is connected to the wheel cylinder 126 of the right front wheel through the passage 120, the solenoid valve 122 and the passage 124.
It is also connected to the wheel cylinder 136 of the left rear wheel via 30, the solenoid valve 132 and the passage 134. Each solenoid valve 1
22 and 132 are always wheel cylinders 126 and
Isolate 136 from reservoir 140 to remove master cylinder 1
14 is in a pressure-increased state in which the wheel cylinders 12 are in communication with each other.
6, 136 from the reservoir 140 to the master cylinder 11
It is possible to appropriately switch between a pressure holding state in which the pressure is also shut off from No. 4 and a pressure reduction state in which the master cylinder 114 is shut off to communicate with the reservoir 140.

The reservoir 140 is connected to the passage 120 via a pump 146. The pump 146 is the motor 1
Driven by 48, the brake fluid in the reservoir 140 is pumped up and collected in the master cylinder 114 via the passage 120. The motor 148 is also controlled by the controller 144.

As shown in FIG. 4, the controller 144 has a CPU 150, a ROM 152 (see FIG. 5), and a RAM.
154 (see FIG. 6), an input port 156 and an output port 158 are included. A brake switch 160 for detecting the depression of the brake pedal 110 is connected to the input port 156, while the solenoid valves 122 and 132 and the motor 148 are connected to the output port 158.
And are connected.

The controller 144 is a ROM 152.
The anti-lock control routine (represented by the flowchart in FIG. 7) is stored in advance, and the slip ratio of each wheel is excessive during vehicle braking while monitoring the relationship between the wheel speed V _{W of} each wheel and the estimated vehicle speed V _S0. Anti-lock control is performed to prevent this from happening.

As shown in FIG. 8, each wheel 14 is a wheel with a tire having a tire 26 attached to the outer periphery of the wheel 24. However, as shown in FIG. It can be considered that the portion 30 and the portion 30 are connected by the torsion spring 32. In the present embodiment, the wheel speed V _W means the rotational speed of the belt side portion 30, and is calculated as the product of the angular speed ω _B of the belt side portion 30 and the actual radius R of the tire 26. Therefore, the input port 156 of the controller 144 is further provided with
As shown in FIG. 5, an auxiliary computing device 170, which will be described in detail later, is also connected, from which the belt side angular velocity ω _B and the actual radius R
And are to be supplied respectively. The supplied belt side angular velocity ω _B and the real radius R are stored in the RAM 154.

On the other hand, the estimated vehicle speed V_S0Is the controller 14
Estimated vehicle speed calculation rules stored in advance in the ROM 152 of No. 4
4 wheel speeds for the front left and right wheels and the rear left and right wheels
Degree V _WIs calculated based on. Specifically, those 4
Individual wheel speed V_WThe largest of these and the previous estimated car
Speed V_S0Estimated maximum speed and the previous estimated vehicle speed V
_S0Of the three candidate speeds consisting of the minimum speed assumed from
Estimated vehicle speed V this time for medium size_S0Is determined
Is calculated. Estimated vehicle speed V calculated_S0Is
It is stored in the RAM 154.

Here, the "maximum speed" is the upper limit acceleration G.
_ACC (fixed value) and the sampling cycle α of the estimated vehicle speed V _S0 are used to _express V _S0 + G _ACC · α, while the “minimum speed” is the upper limit deceleration G
It is expressed using the equation V _S0 −G _DEG · α using _DEG (fixed value) and the sampling period α.

The controller 144 detects the friction coefficient μ between the tire and the road surface prior to each antilock control. The friction coefficient μ is detected by using a motion equation that is established for each of the left and right front wheels that are non-driving wheels when the vehicle is being braked, that is, an expression of J _R ω _R '+ J _B ω _B ' + T ₁ = μF _Z R Be seen.

Where J _{R is the} moment of inertia of the rim side portion 28 J _{B is the} moment of inertia of the belt side portion 30 ω _R ': Angular acceleration of the rim side portion 28 (time differential value of the angular velocity ω _R ) ω _B ': Belt Angular acceleration of the side portion 30 (time differential value of the angular velocity ω _B ) T ₁ : Braking torque applied to the rim side portion 28 F _Z : Load acting on the wheel 14 in the vertical direction from the ground contact surface (hereinafter referred to as wheel load) R : Real radius of the wheel 14 (= distance between the rotation center of the wheel 14 and the contact surface)

When considering the establishment of the equation of motion, the left and right front wheels which are non-driving wheels are selected instead of the left and right rear wheels which are driving wheels. This is because not only the braking torque by the brake but also the braking torque by the engine brake is applied to the portion 28, and the calculation becomes complicated.

Of the various variables in the above equation of motion, the inertia moments J _R and J _B of the rim side portion 28 and the belt side portion 30 are both fixed values, but all other variables are variable values. ing. The inertia moments J _R and J _B can also be calculated as variable values by applying a disturbance observer described later, which is described in detail in Japanese Patent Application No. 5-190204 of the present applicant. There is.

[0033] The controller 144, the angular acceleration omega _R of the rim 28 and the belt side 30 ', ω _B' angular velocity of each omega _R, is computed as the time differential value of omega _B, they angular velocity omega _R, omega _B Is calculated by the auxiliary arithmetic unit 170 and supplied to the controller 144.

The controller 144 also applies a braking torque to each front wheel by a braking torque detection routine (not shown) stored in advance in the ROM 152 based on the brake pressure in the pressurizing chamber of the master cylinder 114 connected to the front wheel. Calculate the torque T ₁ . A brake pressure sensor 172 is connected to the input port 156 for detecting the brake pressure. The calculated braking torque T ₁ is stored in the RAM 154.

Further, the controller 144 has the ROM 1
The 52 previously stored wheel load detection routine (not shown), for detecting a wheel load F _Z acting on the front wheels. A wheel load sensor 174 for the left front wheel and a wheel load sensor 176 for the right front wheel are connected to the input port 156 for detecting the wheel load. Controller 1
44 detects the wheel loads F _Z of the left and right front wheels,
The wheel load F _Z of each front wheel is detected as the average value thereof. The detected wheel load F _Z is stored in the RAM 154.

The friction coefficient μ calculated by the above equation of motion represents the friction coefficient between the tire and the road surface to the last, and does not always match the friction coefficient of the road surface. Because the friction coefficient between the tire and the road surface is a relative value that fluctuates in relation to the slip ratio of the wheels, whereas the friction coefficient of the road surface is an absolute value that is determined independently of the slip ratio of the wheels. Is. On the other hand, it can be estimated that the peak value of the coefficient of friction between the tire and the road surface represents the coefficient of friction of the road surface, and at the time when the coefficient of friction between the tire and the road surface shows the peak value, the slip ratio of the wheels is in the proper range. It is a time close to the upper limit value of, and if it is left as it is, there is a possibility that it will deviate from the appropriate range, so that it substantially coincides with the time when it is determined that it is necessary to start the antilock control. Therefore, in this embodiment, the value of the friction coefficient μ in the RAM 154 is sequentially updated until the antilock control is started, but once the antilock control is started, the calculation of the friction coefficient μ is stopped. The value of the friction coefficient μ is fixed and functions as a road surface friction coefficient.

Here, the auxiliary arithmetic unit 170 will be described in detail. The auxiliary computing device 170 is provided on each of the four wheels, and each is configured as shown in the functional block diagram of FIG. 10 and the configuration block diagram of FIG. 11.

In FIG. 11, 10 is a rotor and 12 is an electromagnetic pickup. The rotor 10 rotates together with the wheels 14 and has a large number of teeth 16 on its outer circumference. The electromagnetic pickup 12 generates a voltage that changes periodically as the teeth 16 pass. This voltage is shaped into a rectangular wave by the waveform shaper 18, and the computer 2
0 I / O port 22. Since the rotor 10 is mounted so as to rotate integrally with the wheel 24, the electromagnetic pickup 12 is, strictly speaking, the rim side portion 2.
The angular velocity ω _R of 8 will be detected.

The computer 20 is C as shown in FIG.
It has a PU 40, a ROM 42 and a RAM 44,
By storing an angular velocity calculation routine (not shown) in the ROM 42, the rotor 10 and the electromagnetic pickup 1 are stored.
2 and the waveform shaper 18 together with the angular velocity detector 4 of FIG.
6 is composed.

The computer 20 calculates the rotation speed V _R of the rim side portion 28 of the wheel 14 based on the signals supplied from the electromagnetic pickup 12 and the waveform shaper 18.
The rotation speed V _R is calculated from the average of the rising time intervals of the rectangular wave from the waveform shaper 18 within a predetermined fixed sampling time.

First, within a predetermined sampling time
And end of the first and last rise of a square wave in
The number of rises within the ring time is detected.
Each time a rising edge occurs, the interrupt routine
When the time indicated by the timer built into the data 20 is read
Anyway, the number of rises is counted. Continued
The average rotation speed of the wheels 14 within the sampling time
The degree is calculated. All the samples within the sampling time
The average time interval between rises is calculated, and that value is calculated on the rim side.
Rim side 28 by dividing by the radius of 28 (fixed value)
Angular velocity ω _RIs calculated and stored in the angular velocity memory of RAM44.
It is stored.

This computer 20 is connected to another computer 47 as shown in FIG. The computer 47 also includes a CPU 48, a ROM 49, a RAM 50, and an I / O port 51, and various controls such as a routine for performing calculations of equations described later in the ROM 49 and a correlation calculation routine shown in the flowchart of FIG. By storing the program, the disturbance observer 52, the correlation calculator 56, the normalizer 58, the tire pressure calculator 60, and the real radius determiner 61 shown in FIG. 10 are configured.

The disturbance observer 52 is constructed based on the model of the wheel 14 shown in FIG. The configuration of the disturbance observer 52 will be described below. Wheels 14
If the inertia moment J _R of the rim side portion 28 and the inertia moment J _B of the belt side portion 30 are modeled as connected by a torsion spring 32 having a spring constant K, the following equation of state is obtained.
(1) to (3) are satisfied. J _R ω _R ′ = −K (θ _R −θ _B ) + T ₁・ ・ ・ (1) J _B ω _B ′ = K (θ _R −θ _B ) −T _d・ ・ ・ (2) θ _RB = θ _R− θ _B・ ・ ・ (3)

Where ω _R : angular velocity of the rim side portion 28 ω _R ′: angular acceleration of the rim side portion 28 ω _B : angular velocity of the belt side portion 30 ω _B ′: angular acceleration of the belt side portion 30 _RB : rim side Torsion angle between the portion 28 and the belt side portion 30 (difference between the rim side rotation angle θ _R and the belt side rotation angle θ _B ) T ₁ : Braking torque applied to the rim side portion 28 T _d : Torque from road surface (The sum of the disturbance torque and the rotational load torque) Although a damper is actually present between the inertia moment J _R of the rim side portion 28 and the inertia moment J _B of the belt side portion 30, the influence is compared. Because it is small, it can be ignored.

If the above equation of state is expressed using a vector and a matrix, the following equation (4) is obtained.

[0046]

[Equation 1]

Here, the movement of the wheel 14 when the air pressure of the tire 26 changes and the spring constant of the torsion spring 32 changes from K to K + ΔK is expressed by the following equation (5).

[0048]

[Equation 2]

That is, the change of the spring constant K by ΔK is equivalent to the disturbance torque represented by the final term of the equation (5) being applied to the normal tire 26. This disturbance torque includes information on the amount of change ΔK of the spring constant K, and changes according to the air pressure of the tire 26. Therefore, by estimating the disturbance torque, the amount of change of the air pressure of the tire 26 is estimated. can do. The disturbance observer method is used to estimate this disturbance torque, and the disturbance torque to be estimated is expressed by the following equation (6).

[0050]

[Equation 3]

However, since only one element in the vector [w] can be theoretically estimated, the second element w ₂ is estimated. If the disturbance torque is defined by the following formula (7) w ₂ = (− 1 / J _B ) T _d + (ΔK / J _B ) θ _RB (7), the state equation of the wheel 14 is Since the equation (8) is obtained, the disturbance observer 52 is constructed based on this equation.

[0052]

[Equation 4]

The disturbance observer 52 estimates the disturbance torque as one of the state variables of the system. Therefore, in order to include the disturbance torque w ₂ of the above equation (7) in the system state, the dynamics of the disturbance torque w ₂ is given by the following (9)
It approximates with a formula. w ₂ ′ = 0 (9) This means that the disturbance torque that continuously changes as shown in FIG. 13 is approximated stepwise (zero-order approximation), and the estimated disturbance velocity of the disturbance observer 52 is This approximation is well tolerated if it is sufficiently fast compared to the change in disturbance torque to be estimated. From the above equation (9), when the disturbance torque is included in the state of the system, the extended system of the following equation (10) is constructed.

[0054]

[Equation 5]

[Ω _B θ _RB w ₂ ] in the above equation (10)
^T cannot be detected. Therefore, if the disturbance observer 52 is configured based on this system, the disturbance torque w ₂ and the undetectable state variables ω _B and θ _RB can be estimated. To simplify the description, the vector and matrix in Eq. (10) are decomposed and expressed as follows.

[0056]

[Equation 6]

At this time, the state [z] = [ω _R θ _RB w
₂ ] The configuration of the minimum dimensional observer for estimating ^T is given in (11) below.
It is represented by a formula. [Z _p ′] = [A ₂₁ ] [x _a ] + [A ₂₂ ] [z _p ] + [B ₂ ] [u] + [G] {[x _a ′] − ([A ₁₁ ] [x _a ] + [A ₁₂ ] [z _p ] + [B ₁ ] [u])} = ([A ₂₁ ] − [G] [A ₁₁ ]) [x _a ] + ([A ₂₂ ] − [G] [ _{A 12]) [z p]} + [G] [x a '] + ([B 2] - [G] [B 1]) [u] ··· (11) However, [z _p]: [z ] Estimated value [z _p ′]: change rate of estimated value [z _p ] [G]: gain that determines the estimated speed of the disturbance observer 52 [u]: braking torque T ₁ [B ₁ ]: 1 / J _R [ B ₂ ]: [0 0 0] ^T This is shown in a block diagram in FIG. 14.

If the error [e] between the true value and the estimated value is set as [e] = [z]-[z _p ] and the rate of change of the error [e] is [e '], then Obtain the relation of equation (12). [E ′] = ([A ₂₂ ] − [G] [A ₁₂ ]) [e] ... (12) This represents the estimated characteristics of the disturbance observer 52, and the matrix ([A ₂₂ ] − [G ] [A ₁₂ ]) is the pole of the disturbance observer 52. Therefore, the estimated speed of the disturbance observer 52 becomes faster as the eigenvalue is farther from the origin on the left half surface of the s-plane. The observer gain [G] may be determined so as to have a desired estimated speed.

Disturbance observer 5 constructed as described above
2, the angular velocity ω _R of the rim side portion 28 calculated by the angular velocity detector 46 and the braking torque T ₁ are input, and the spring constant K of the torsion spring 32 is expressed by the equation (7) when the spring constant K changes by ΔK. The disturbance torque w ₂ is estimated, and the disturbance torque estimated value w _2p is acquired, but the angular velocity ω _B of the belt side portion 30 and the twist angle θ between the rim side portion and the belt side portion which cannot be detected together with the disturbance torque w _2p are acquired. _{RB is} also estimated, and the estimated values ω _Bp and θ _RBp are obtained, respectively.

Estimated values w of the above disturbance torque and torsion angle
Correlation calculation is performed in the correlation calculation unit 56 using _2p and θ _RBp , and normalization is performed in the normalization unit 58 to obtain the change in the spring constant K of the torsion spring 32.

First, the correlation calculation unit 56 executes the correlation calculation routine represented by the flowchart of FIG. In step S21 (hereinafter, simply referred to as S21; the same applies to other steps), the integer i is reset to 1, and the disturbance torque w represented by the equation (7) is set.
₂ estimate w _2p cross-correlation value between the estimated torsion angle value _{θ RBp C (w 2p, θ} RBp) and estimated torsion angle value theta _RBp of the autocorrelation values C (θ _RBp, θ _RBp) and is reset to 0 To be done. The contents of the cross-correlation value memory and the auto-correlation value memory are set to zero.

Subsequently, in step S22, the current estimated disturbance value w
_2pi and estimated torsion angle value theta _rBPI is read, S23
In the operation the product of the estimated torsion angle value theta _rBPI the estimated disturbance value w _2pi, the cross-correlation value C (w _2p, θ _RBp) is added to.
However, when S23 is executed for the first time, the cross-correlation value C
(W _2p, θ _RBp) since it is 0, it is only the product of the cross-correlation value memory and the estimated disturbance value w _2pi and estimated torsion angle value theta _rBPI is stored. Similarly, in S24, the estimated twist angle θ
The square of _RBpi is calculated and added to the autocorrelation value C (θ _RBp , θ _RBp ) in the autocorrelation value memory.

In S25, it is determined whether or not the integer i has become equal to or greater than the predetermined integer M. However, the determination is initially NO, so the integer i is incremented by 1 in S26, and S22 to S24 are executed again. To be executed. When this execution is repeated M times, the determination in S25 becomes YES, and one execution of the correlation calculation routine for acquiring the spring constant change ends.

As described above, the correlation calculating unit 56 calculates the cross-correlation value C (w _2p , θ _RBp ) and the autocorrelation value C.
After (θ _RBp , θ _RBp ) is obtained, the following equation (13) L _k = C (w _2p , θ _RBp ) / C (θ _RBp , θ _RBp ) ... (13) ), The L _K value is obtained and stored in the L _K value memory of the RAM 50. This L _K value is expressed by the following equation (14) L _k = (− 1 / J _B ) C ₀ + ΔK / J _B (14) where C ₀ is C (T _dp , θ _RBp ) / C (θ _RBp , θ
_RBp ), which is independent of the change in the spring constant K, and can be compensated by _obtaining the tire pressure p in advance under normal conditions.

[0065] In the tire pressure calculating unit 60, more than to be acquired as, L _K stored in the L _K value memory
Change amount ΔK of the spring constant K of the torsion spring 32 based on the value
Is calculated. The L _K value is (-1 / J _B ).
Since it is a value corresponding to C ₀ + ΔK / J _B , there is a fixed relationship between the L _K value and the spring constant change amount ΔK, and between this spring constant change amount ΔK and the tire pressure change amount Δp. Since there is also a constant relationship, there is a constant relationship between the L _K value and the tire pressure change amount Δp. This relationship is stored in advance in the ROM 49 as a tire pressure change amount table, and the tire pressure change amount Δp is obtained from the L _K value based on this table. Since this tire pressure variation Delta] p is the change amount from the tire pressure p ₀ of the normal value from the tire pressure p ₀ of the normal minus the tire pressure variation Delta] p p =
p ₀ −Δp is calculated as the current tire pressure p, RAM
Stored in 50 tire pressure memory.

The tire pressure p calculated as described above by the tire pressure calculation unit 60 is supplied to the real radius determination unit 61 of FIG. The real radius determination unit 61 does not show the real radius table in which the relationship between the tire pressure p and the real radius R is tabulated in the ROM 49, and the real radius R is determined based on the tire pressure p and the real radius table (not shown). And a real radius determination routine. Deformation of the tire 26 increases as the tire pressure p decreases, and the actual radius R
Becomes smaller. The relationship between the tire pressure p and the real radius R is measured in advance and stored in the ROM 49 as a real radius table.

Based on the information including the rim side angular velocity ω _R , the belt side angular velocity ω _B and the actual radius R calculated as described above, the controller 144 executes the antilock control routine of FIG.

The contents of this antilock control routine will be described in detail below. It should be noted that this routine is repeatedly executed by setting each wheel as an execution target wheel in order,
Hereinafter, a case where one of the left and right front wheels is the execution target wheel will be representatively described, and description of the other cases will be omitted. When the controller 144 is powered on, a control flag F _ABS used in this routine, which will be described later, is initialized to 0, and the control mode executed for the brake pressure is initialized to the normal brake mode. Also, the number of continuous pulse pressure increases is initialized to zero.

First, in S41, from the RAM 154
Belt side angular velocity ω_BThis time value and the actual radius R of the tire 26
This time's value and are read respectively. Next, in S42
And those belt side angular velocity ω_BAnd product of real radius R
Belt side rotation speed V _BThe current value of
This is the wheel speed V_WThis time it will be the value. Then, to S43
From the RAM 154, the wheel speed V_WRead the previous value of
Wheel speed V _WSubtract the previous value from the current value of
The wheel acceleration V_WThe current value of 'is calculated.

Next, at S44, the control flag F
It is determined whether _ABS is 1. Assuming that the current execution of this routine is the first time after the controller 144 is powered on, the in-control flag F _ABS is currently 0. Therefore, the determination in S44 is NO, and the process proceeds to S45.

In S45, the RAM 154
, Rim side angular velocity ω_RCurrent value and previous value and belt
Lateral angular velocity ω_BThe current value and the previous value of
And subtract the previous value from the current value for each
This adds corners to the rim side portion 28 and the belt side portion 30.
Speed ω_R’, Ω_BThe current value of 'is calculated. Then S
46, from the RAM 154, the braking torque T₁， Real
Radius R and wheel load F _ZAre read respectively, and next
Then, in S47, they and the angular acceleration ω_R’And
Ω_B’And by substituting into the above equation of motion,
The present value of the friction coefficient μ between the tire and the road surface is calculated.

Thereafter, in S47, the control reference speed difference ΔV ₁ is calculated. In this anti-lock control, the control mode of the brake pressure is the normal brake mode, the pressure reduction mode, and the maintenance mode based on the wheel speed difference ΔV and the wheel acceleration V _W ′, which are the values obtained by subtracting the wheel speed V _W from the estimated vehicle speed V _S0. Either the pressure mode or the pulse pressure increasing mode is appropriately determined. A control reference speed difference ΔV ₁ exists as a comparison target of the wheel speed difference ΔV.
₁ is calculated as the product of the control reference speed difference ΔV ₀ , which is a fixed reference value, the friction coefficient μ, and the correction coefficient k.

Subsequently, in S48, it is determined whether or not the current value of the wheel acceleration V _W 'is less than or equal to the negative reference acceleration G ₁ . It is determined whether or not there is a strong increasing tendency in the locking tendency of the wheels. Assuming that there is no strong increasing trend this time, the determination is NO and S
At 49, it is determined whether or not the control flag F _ABS is 1. Since it is currently assumed to be 0, the determination is NO, and the normal brake mode is executed in S50. The solenoid valves 122 and 132 are put into a pressure-increased state, and the brake pressure of the wheel cylinders 126 and 136 is made to increase in accordance with the pedaling force of the brake pedal 110, so that a normal braking state is brought about. Thus, one execution of this routine is completed.

After that, if it is assumed that the stepping force of the brake pedal 110 becomes excessive in relation to the friction coefficient of the road surface while the execution of S41 to 50 is repeated and a strong increasing tendency appears in the wheel lock tendency, The judgment is YE
In S51, the present value of the wheel speed difference ΔV is calculated by subtracting the present value of the wheel speed V _W from the present value of the estimated vehicle speed V _S0 in S51. Then, in S52, it is determined whether or not the wheel speed difference ΔV is larger than the current value of the control reference speed difference ΔV ₁ . It is determined whether or not the reduction amount of the wheel speed V _W with respect to the estimated vehicle speed V _S0 becomes excessive. Assuming it is not oversized this time,
The determination is NO. Thus, one execution of this routine is completed. In this execution of this routine, the control mode of the brake pressure is not updated, the control mode of the last time is maintained, and this time, the normal brake mode is subsequently executed this time.

After that, if it is assumed that the decrease amount of the wheel speed V _W with respect to the estimated vehicle speed V _S0 becomes excessive while the execution of S41 to 48, 51 and 52 is repeated, it is necessary to start the antilock control. Is determined, the determination in S52 is YES, and in S53, the control flag F
_ABS is set to 1, whereby the fact that the antilock control has been started is stored in the RAM 154. After that, S5
4, the depressurization mode is executed and the solenoid valves 122, 1
32 is continuously switched to the depressurized state, the brake pressure of the wheels is rapidly reduced, and the increase of the lock tendency is suppressed. Thus, one execution of this routine is completed.

At the next execution of this routine, since the control flag F _ABS is 1, the determination in S44 is YE.
S becomes, and S45 to 47, that is, mainly the friction coefficient μ
The step group relating to the calculation of is skipped and the process proceeds to S48. That is, the friction coefficient μ is updated every time the routine is executed until the antilock control is started, but when the antilock control is started, the update is prohibited and fixed. The value of the friction coefficient μ after the start of control accurately represents the friction coefficient of the road surface.

After that, if the wheel acceleration V _W 'becomes larger than the reference acceleration G ₁ due to the reduction of the brake pressure and the determination in S48 becomes NO, the process proceeds to steps S49 and below. Since the control-in-progress flag F _ABS is currently 1, the determination in S49 is YES, and in S55, it is determined whether or not the wheel acceleration V _W 'is larger than the positive reference acceleration G ₂ . It is determined whether or not a strong decrease tendency appears in the wheel lock tendency. Assuming that the strong decreasing tendency does not appear this time, the determination is NO, and the above is the end of one execution of this routine. In this execution of this routine, the control mode of the brake pressure is not updated, the previous control mode is maintained, and this time, the depressurization mode is subsequently executed this time.

Thereafter, assuming that the wheel acceleration V _W 'has become greater than the reference acceleration G ₂ while the execution of S41 to 44, 48, 49 and 55 is repeated, S55
Is YES, and in S56, the wheel speed difference Δ
The current value of V is calculated. Then, in S57, it is determined whether or not the wheel speed difference ΔV is less than or equal to the control reference speed difference ΔV ₁ . It is determined whether the wheel speed V _W tends to be too close to the estimated vehicle speed V _S0 . If this is not the case this time, the determination is no, and in S58, the pressure holding mode is executed for the brake pressure. Thus, one execution of this routine is completed.

After that, S41 to 44, 48, 49, 55
If it is assumed that the wheel speed difference ΔV becomes equal to or smaller than the control reference speed difference ΔV ₁ while the execution of steps 58 to 58 is repeated, S5
The determination result in 7 is YES, and in S59, the pulse pressure increasing mode is executed for the brake pressure. Solenoid valve 12
The brake pressure is gradually increased by alternately supplying the pressure increasing signal and the pressure maintaining signal to 2, 132, whereby the wheel speed V _W approaches the estimated vehicle speed V _S0 too much and the braking force is increased. Occurrence of shortage is avoided. Then, in S60, it is determined whether or not the pulse pressure increasing mode has been executed a predetermined number of times.

Here, the "number of times of the pulse pressure increasing mode" means the number of times the pulse pressure increasing mode is executed when the pulse pressure increasing mode is continuously and repeatedly executed.
This corresponds to the number of times this routine is executed when a series of pulse pressure increasing modes is executed. That is, the number of times of the pulse pressure increasing mode means the continuous time of a series of pulse pressure increasing modes. The number of times of the pulse pressure increasing mode is monitored in this manner in order to prevent the braking distance from being unnecessarily increased by the antilock control. The reason why the pulse pressure increasing mode is continuously executed for a long time is that the friction coefficient of the road surface is not effectively used, which means that the braking pressure is insufficient, that is, the braking force is insufficient. Assuming that the pulse pressure increasing mode has not been executed a predetermined number of times this time, the determination becomes NO, and one execution of this routine ends.

After that, S41 to 44, 48, 49, 55
If it is assumed that the pulse pressure increasing mode has been executed a predetermined number of times while the execution of ~ 57, 59, 60 is repeated, S6
The determination of 0 is YES, the in-control flag F _ABS is set to 0 in S61, and the control mode of the brake pressure is restored to the normal brake mode in S50. As a result, the brake pressure is allowed to be increased according to the depression force of the brake pedal 110. Thus, one execution of this routine is completed.

As is apparent from the above description, in the present embodiment, the angular velocity detecting section 46 constitutes one aspect of the "rim side angular velocity detecting means 1" in the invention of each claim, and the computer 47 and the controller 144. S4 in Figure 7
The portion that executes steps 1 and 42 constitutes one aspect of the "belt side rotation speed determining means 2", and the solenoid valves 122 and 132 constitute one aspect of the "motion control mechanism 3". Further, S44 to S46 of FIG. 7 of the controller 144, a portion that executes the braking torque detection routine and the wheel load detection routine, the brake pressure sensor 172, and the wheel load sensor 17
4, 176 constitute one mode of the "friction coefficient detecting means 5", and execute the estimated vehicle speed calculation routine of the controller 144 except the steps S41, 42, 44 to 46 in the antilock control routine. The part to do constitutes one aspect of the "controller 4".

In the above embodiment, the friction coefficient μ is detected based not only on the belt side angular velocity ω _B but also on the rim side angular velocity ω _R. It is also possible to carry out the invention of each claim such that the friction coefficient μ is detected only based on the angular velocity ω _B.

Although one embodiment common to the inventions of claims 1 and 2 has been described in detail with reference to the drawings, the invention is applied to various vehicle controls other than the antilock control. It can be implemented in a modified form.

[Brief description of drawings]

FIG. 1 is a block diagram conceptually showing the structure of the invention of claim 1. FIG.

FIG. 2 is a block diagram conceptually showing the structure of the invention of claim 2.

FIG. 3 is a system diagram showing a brake system including an anti-lock control device, which is an embodiment common to the inventions of claims 1 and 2.

FIG. 4 is a functional block diagram of the antilock control device.

5 is a diagram conceptually showing the structure of the ROM of the controller in FIG.

6 is a diagram conceptually showing the structure of the RAM of the controller in FIG.

7 is a flowchart showing an antilock control routine in FIG.

FIG. 8 is a cross-sectional view showing a part of a wheel.

FIG. 9 is a diagram showing a dynamic model of the wheel.

10 is a functional block diagram showing details of an auxiliary arithmetic unit in FIG.

FIG. 11 is a configuration block diagram showing details of the auxiliary arithmetic device.

12 is a flowchart showing a correlation calculation routine stored in a ROM of the controller shown in FIG.

FIG. 13 is a diagram for explaining the approximation of the dynamics of a disturbance torque in a disturbance observer which is a part of the auxiliary computing device.

FIG. 14 is a block diagram showing the disturbance observer.

[Explanation of symbols]

 10 rotor 12 electromagnetic pickup 14 wheel (= wheel with tire) 20 computer 24 wheel 26 tire 28 rim side part 30 belt side part 32 torsion spring 46 angular velocity detection part 47 computer 144 controller 170 auxiliary computing device 172 brake pressure sensor 174, 176 wheel Load sensor

Claims (2)

[Claims] 1. A rim side angular velocity detecting means for detecting a rim side angular velocity of a tire wheel of a vehicle, a detected rim side angular velocity, and a rim side moment of inertia and a belt side inertia of the tire wheel. Based on the moment and the torsion spring constant between the rim side portion and the belt side portion, the belt side angular velocity of the tire-equipped wheel is estimated, and the belt side is estimated based on the estimated belt side angular velocity and the radius of the tire-equipped wheel. The belt side rotation speed determining means for determining the section rotation speed, the movement control mechanism for controlling the movement of the vehicle, and the movement of the vehicle through the movement control mechanism based on the determined belt side rotation speed. A vehicle control device comprising: a controller for controlling. 2. Further, based on at least the determined belt side rotation speed,
It includes a friction coefficient detecting means for detecting a friction coefficient between the tire and a road surface with which the tire is in contact, and the controller controls the movement of the vehicle based on at least the friction coefficient detected by the friction coefficient detecting means. The vehicle control device according to claim 1, which controls the vehicle.