JPH066426B2 - Vehicle braking control device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle braking control device, and more particularly, to optimally control a braking pressure during vehicle braking based on a dynamic model of a system relating to vehicle braking. The present invention relates to a braking control device for a vehicle.

[Prior Art] Conventionally, there is a decrease in safety due to wheel locking during vehicle braking, that is, vehicle front wheel locking causes the vehicle to become uncontrollable,
In order to prevent the tail swing phenomenon (skid) from occurring due to the locking of the rear wheels of the vehicle, the slip ratio S [(vehicle body speed-wheel rotational speed) / body speed] of each vehicle wheel is set to 1
There is known a vehicle braking control device, a so-called anti-skid control device, which controls the rotational speed of wheels so that the frictional force between the tire and the road surface is maximized by controlling the friction force between 5 and 20% (for example, Japanese Patent Laid-Open No. 58-58). 122248, etc.). In this type of anti-skid control device, the wheels are not locked when the vehicle is braked, and moreover, the frictional force between the tire and the road surface is maximized so that the vehicle can be stopped quickly, normally, the rotational speed is detected for each wheel, The rotation speed is, for example, the vehicle body speed Vs.
Based on the following equation V = Vs (1-S) (where S is a slip ratio of 0.15 to 0.2), the brake hydraulic pressure is controlled to increase or decrease when the reference speed V is increased or decreased. The rotation speed of the wheels is controlled to be the reference speed. That is, for example, as shown in FIG. 2, when the rotation speed V1 of the wheel is lower than the reference speed V, the brake pressure of the wheel is reduced, and then the rotation speed V1 is reduced.
By repeating the brake pressure control such that the brake pressure is increased when exceeds the reference speed V, the rotational speed of the wheels is made to approach the reference speed.

[Problems to be Solved by the Invention] However, in the above-described conventional anti-skid control device, the rotation speed of each wheel is controlled by individually controlling the brake hydraulic pressure of each wheel based on the so-called classical feedback control theory. Therefore, there is a problem in that the braking balance is lost due to variations in the wheels due to wear of the tires, etc., and the vehicle shifts laterally or cannot be stopped immediately. Further, even with respect to each wheel, it is extremely difficult to control the rotation speed thereof to the reference speed, and it is possible to control the rotation speed to be close to the reference speed. Therefore, the braking distance cannot be minimized.

Therefore, the present invention has been made for the purpose of providing a vehicle braking control device for controlling the braking pressure of each wheel based on the so-called modern control theory so that the vehicle braking control can be executed more quickly and stably. It has the following configuration.

[Means for Solving the Problems] That is, according to the present invention, as illustrated in FIG. 1, a rotation speed detecting means M4 for detecting the rotation speed of each wheel M3 of the vehicle M1, and a drive signal supplied thereto, Brake pressure adjusting means M6 for adjusting the brake pressure transmitted to the braking member M5 of each wheel M3, target rotation speed setting means M8 for setting the target rotation speed of each wheel M3 of the vehicle M1, and each of the detected above The brake pressure of the braking member M5 for controlling the rotation speed of the wheel M3 to the set target rotation speed of each wheel M3 is determined, and a drive signal corresponding to the brake pressure is output to the brake pressure adjusting means M6. A braking control device for a vehicle comprising: a braking control means M9 for controlling the braking control means M9, and the braking control means M9 is preset based on a dynamic model of a system relating to braking of the vehicle M1. By using the parameter, the rotational speed of each wheel M3 detected by the rotational speed detecting means M4 and the brake fluid force of the braking member M5 adjusted by the brake pressure adjusting means M6 are used to determine the system concerned. A state observing unit M11 that estimates a state variable amount of an appropriate degree that represents a dynamic internal state, a rotation speed detected by the rotation speed detecting unit M4, and the target rotation speed setting unit M8 for each wheel M3. The accumulator M12 that obtains a deviation from the target rotation speed set in step S6 and calculates an integral value or an accumulated value of the deviation, the estimated state variable amount, the calculated integrated value or the accumulated value, and A brake pressure determining unit M13 that determines the brake pressure of the braking member M5 based on the set optimum feedback gain, and an additional integral type optimum regulator. It is characterized by that.

[Operation] In the vehicle braking control device of the present invention configured as described above, the brake pressure adjusting means M6 is the braking control means M.
By the drive signal output from 9, the rotation speed of each wheel M3 is controlled to be the target rotation speed.

The braking control means M9 is configured as an additional integral type optimum regulator, and in the state observing section M11, the braking pressure of the braking member M5 serving as a control input and the rotation speed of each wheel M3 serving as a control output are used to determine the vehicle. The state variable amount indicating the dynamic internal state of the system relating to braking is estimated, and the cumulative value M12 calculates the integrated value or cumulative value of the deviation between the rotation speed of each wheel M3 and the target rotation speed, and the brake pressure determination unit. At M13, a target optimum control input (that is, the braking pressure of the braking member) is determined by using a preset optimum feedback gain based on the state variable amount and the integrated value or the accumulated value.

As described above, in the present invention, unlike the conventional feedback control, only the deviation between the rotation speed of each wheel and the target rotation speed is not used as the parameter for calculating the control input, but the dynamics of the system relating to the braking of the vehicle Such internal state is estimated as a state variable amount, and this state variable amount is also used as a parameter for control input calculation. Therefore, it is possible to control the brake pressure of the braking member of each wheel to an optimum brake pressure for bringing the rotation speed of each wheel close to the target rotation speed while taking the state of the braking system of the vehicle into consideration.

[Examples] Hereinafter, examples of the present invention will be described. Before the description of specific examples to which the present invention is applied, an outline of the present invention configured as described above will be described.

First, the rotation speed detecting means M4 is provided for each wheel in order to detect the rotation speed of each wheel M3 of the vehicle, and is a conventionally known power generation type rotation sensor, Hall element type rotation sensor, photoelectric sensor. A rotational speed sensor or the like may be used to detect the rotation speed of the wheel rotation shaft. The braking member M5 is also provided on each wheel M3 of the vehicle, but a conventional brake such as a so-called air brake driven by gas pressure or a hydraulic brake driven by hydraulic pressure can be used as it is, The pressure is adjusted and transmitted by the brake pressure adjusting means M6.

Next, the target rotation speed setting means M8 sets the target rotation speed of each wheel M3, and detects the vehicle body speed using a vehicle speed sensor, an acceleration sensor, etc., like a conventional anti-skid control device, for example. The target rotation speed of each wheel M3 may be set based on the detected vehicle body speed and slip ratio so that the slip ratio of each wheel M3 during vehicle braking becomes a predetermined value. Further, the slip ratio when setting the target rotation speed is, for example, according to the depression amount of the brake pedal, when the depression amount of the brake pedal is large, it is determined that the driver is requesting a large braking force, and the vehicle is The slip ratio is set to 15 to 20% so that the vehicle stops at the shortest distance, and when the brake pedal depression amount is small,
It may be determined that the driver desires gentle deceleration and the slip ratio may be set to a small value of about 5%.

Next, the braking control means M9 receives a signal from the rotation speed detection means M4 provided on each wheel M3, and receives each signal from each wheel M3.
To output a drive signal to the brake pressure adjusting member M6 so that the rotation speed of the wheel becomes the target rotation speed set by the target rotation speed setting means M8, and adjusts the brake pressure of each wheel. It is realized by using a microcomputer configured with peripheral elements such as ROM and RAM and input / output circuits. The braking control means M9 of the present invention differs from the conventional control circuit used for the anti-skid control in that the optimum feedback gain determined in advance according to the dynamic model of the system relating to the braking of the vehicle. The brake pressure of each braking member M5 is obtained based on the above, and a control signal is output to the brake pressure adjusting member M6.

That is, the braking control means M9 is the target rotation speed setting means M.
It is configured as an additional integral type regulator that determines the optimum control amount from the target rotation speed of each wheel determined in step 8 and the actual rotation speed of each wheel detected by the rotation speed detection means M4.

Here, the method of constructing the optimum integral regulator is described in detail in, for example, Katsuhisa Furuta, "Linear System Control Theory" (Showa 51) Shoshodou, etc. We will give a street perspective.

Another system, wherein the state observer (hereinafter, referred to as an observer) that the amount covered in, y ^* of such signals ^*
Indicates that each is a target value.

In the braking control of the controlled object, here the vehicle, the dynamic behavior of this controlled object is It is known from modern control theory that it is described as. Equation (1) is called the equation of state and equation (2) is called the output equation. Is a state variable quantity that represents the internal state of the system related to vehicle braking, Is each wheel M controlled by the brake pressure adjusting member M6
Vector consisting of 3 brake pressures, Is each wheel M3 of the vehicle detected by the rotation speed detecting means M4.
Is a vector consisting of the rotation speed of. Also, equation (1),
(2) is described in a discrete system, and the subscript k indicates that it is the value at the present time, and k-1 indicates that it is the value at the time of the sampling one time before.

State variable quantity that indicates the internal state of the vehicle braking system Shows information about the history of the system that is necessary and sufficient for predicting the future influence of the control system. Therefore, a dynamic model of the system related to vehicle braking becomes clear, and the vector of equations (1) and (2) is obtained. If we can determine Thus, the braking of the vehicle can be optimally controlled by using.

However, it is difficult to theoretically and accurately obtain a dynamic model of a complex controlled object such as vehicle braking control, and it is necessary to experimentally determine it in some form. This is a so-called system identification method for model building. When the vehicle is brake-controlled under a predetermined condition, linear approximation is established in the vicinity of the state, and the state equations of equations (1) and (2) are expressed as The model is constructed accordingly. Therefore, even if the dynamic model related to the braking is non-linear like a vehicle, it is possible to perform linear approximation by separating into a plurality of stationary conditions, and determine each dynamic model. It is possible.

Here, for example, if the controlled object can construct a physical model relatively easily like a unicycle, system identification is performed by a method such as a frequency response method or a spectrum analysis method, and a dynamic system model ( Vector here ) Can be defined, it is difficult to create a physical model of a multi-dimensional system having a plurality of wheels M3, such as an automobile, to a degree of approximation. In this case, the least squares method or the auxiliary variable method is used. Alternatively, a dynamic model is constructed by an online identification method.

Brake pressure adjusting member M for controlling the brake pressure of the wheel
Various driving conditions of 6 The controlled variable of is theoretically optimally determined. In a normal vehicle braking control system, various amounts directly related to vehicle braking include, for example, load applied to each wheel M3, acceleration, moving speed of oil or gas transmitted to the braking member M5, dynamic behavior of the control member M5, and the like. The state variable amount However, it is extremely difficult to directly observe most of these quantities.

Therefore, in the present invention, the state observing unit M11 is provided in the control means M9.
Is provided, and the state variable amount of the vehicle is estimated from the brake pressure of each wheel and the actual rotation speed.

The state observation unit M11 is an observer in modern control theory, and various observers and their designing methods are known. These are described in detail in, for example, "Mechanical System Control" by Katsuhisa Furuta (Showa 59), Ohm Co., Ltd., etc., and the minimum dimensional observer and It may be designed as a finite set observer.

Next, in the braking control means M9, the state observing part M11 as such an observer is used to measure the state variable amount. And the cumulative value of the deviation between the rotational speed of each wheel M3 and the target rotational speed is calculated by the accumulating unit M12, and the brake pressure determining unit M13 determines both of them and a predetermined optimum feedback. An optimum feedback amount is determined from the gain and the brake pressure adjusting member M
Control 6

Here, the integrated value or the accumulated value of the deviation obtained by the accumulator M12 is an amount required because the target rotation speed changes depending on the operating state of the vehicle such as the vehicle body speed.

That is, generally, in the control of the servo system, it is necessary to perform control to eliminate the steady deviation between the target value and the actual control value.
It is said that it is necessary to include 1 / S ^l (integral of order ¹ ) in the transfer function, and when the transfer function of the system is determined by the system identification as described above and the state equation is constructed from this. It is desirable to include such an integrated amount in terms of noise stability.

Therefore, in the present invention, the control system is expanded to a so-called servo system by adding the integrated value or the accumulated value of the deviation obtained by the accumulating unit M12 to the state variable amount estimated by the state observing unit M11, and both of them are combined. The feedback amount, that is, the brake pressure of each wheel M3 is determined by the predetermined optimum feedback gain.

Next, the optimum feedback gain will be described. In the optimal regulator to which the integral amount is added as described above, it has been clarified how to obtain the control input (here, various amounts of the brake pressure of each braking member M5) that minimizes the evaluation function J, and the optimal feedback gain. Of the solution of the Riccati equation and the state equation (1) and the output equation (2) It is known that it can be obtained from the matrix and the weight parameter matrix used for the evaluation function (supra, etc.). Here, the weight parameter is initially given arbitrarily, and the evaluation function J changes the weight that restricts the behavior of the brake hydraulic pressure of the system that controls the braking of the vehicle. It is possible to determine an optimum value by giving a weighting parameter arbitrarily and performing a simulation by a large computer, changing the weighting parameter by a predetermined amount from the obtained behavior of the brake hydraulic pressure and repeating the simulation. As a result, the optimum feedback gain Is also defined.

Therefore, the braking control means M9 of the braking control device of the present invention is
It is configured as an additional integral type optimum regulator using a dynamic model of the system related to vehicle braking determined in advance by system identification, etc., and observer parameters and optimum feedback gain inside the regulator are added. Are all determined in advance by simulation.

In the above explanation, the state variable amount Has been described as a quantity that represents the internal state of the vehicle, but this need not be a variable quantity that corresponds to an actual physical quantity, but can be designed as a vector quantity of an appropriate order that represents the state of the vehicle.

The outline of the present invention has been described above. Next, a braking device of an embodiment to which the present invention is actually applied will be described.

First, FIG. 3 is a schematic configuration diagram showing the entire braking device of the present embodiment.

In the figure, reference numeral 1 denotes a vehicle to be subjected to braking control, and each wheel 3 to 6 of the vehicle is provided with an electromagnetic pickup type rotation sensor 7 to 10 for detecting its rotation speed. The rotation sensors 7 to 10 correspond to the rotation speed detecting means M4. Further, hydraulic brake devices 13 to 16 corresponding to the braking member M5 are attached to the wheels 3 to 6, respectively, and the brake hydraulic pressure generator 1 is provided.
The rotation of each wheel 3 to 6 can be braked by the brake hydraulic pressure generated from 8. Further, 20 is a depression amount sensor for detecting the depression amount of the brake pedal 21, 22
Is an acceleration sensor that detects the acceleration / deceleration of the vehicle 1. Then, the detection signals from the respective sensors are input to the control circuit 30, and the control circuit 30 calculates the optimum brake hydraulic pressure of each of the brake devices 13 to 16 for vehicle braking based on the detected signal, and the brake hydraulic pressure generator 18 Control signal is output to.

The wheels 3 to 6 are the left front wheels (F
L), right front wheel (FR), left rear wheel (RL), right rear wheel (R)
R), and hereinafter, the rotation speeds of the wheels 3 to 6 detected by the rotation sensors 7 to 10 are Vfl, Vfr, respectively.
It is written as Vrl and Vrr.

Next, the brake hydraulic pressure generator 18 corresponds to the brake hydraulic pressure adjusting member M6, which can be configured as shown in FIG. That is, the brake hydraulic pressure generator 18 transmits the hydraulic pump 33 for pumping up the oil stored in the reservoir 32, the oil pumped by the hydraulic pump 33 to the oil supply pipe 34, and the oil supply pipe 34.
An adjustment valve 35 for adjusting the oil pressure in the oil supply pipe, an accumulator 37 connected to the oil supply pipe via a normally open solenoid valve 36 for preventing the pulsation of the oil in the oil supply pipe 34, and the oil in the oil supply pipe 34. An electromagnetic system that adjusts the brake oil pressure of each hydraulic brake device 13-16 by transmitting the oil to each hydraulic brake device 13-16 and returning the oil in each hydraulic brake device 13-16 to the reservoir 32 via the oil drain pipe 38. And switching valves 41 to 44. Therefore, the oil pressure in the oil supply pipe 34 is always maintained at a predetermined oil pressure, and the pressure in the oil discharge pipe 38 becomes atmospheric pressure. Therefore, a control signal is output to each electromagnetic switching valve 41 to 44 to switch the valve position. The brake hydraulic pressure of the hydraulic brake devices 13 to 16 can be adjusted.

Next, FIG. 5 is a block diagram showing the configuration of the control circuit 30 shown in FIG. As shown in the figure, the control circuit 30 includes an input unit 51 for inputting detection signals from the above-mentioned sensors, a CPU 52 for executing arithmetic processing described later, data used for executing arithmetic processing by the CPU 52, a control program, and the like. RA in which various data are temporarily read and written when the arithmetic processing of the CPU 53 and the ROM 53 in which
An output for outputting a drive signal to each electromagnetic switching valve 41 to 44 shown in FIG. 3 in order to control the hydraulic pressure of each hydraulic brake device 13 to 16 shown in FIG. 3 based on M54 and the calculation processing result thereof. It is composed of a section 55, a data bus 56 which connects the above sections and serves as a passage for various data, and a power supply circuit 57.

In the control circuit 30 configured as above, the vehicle 1 obtained based on the detection results of the rotation speed sensors 9 to 10
Of the vehicle speed immediately before braking and acceleration / deceleration detected by the acceleration sensor 22 from the vehicle speed Vs during braking of the vehicle 1.
Detects the, to each wheel 3 to set the slip ratio S corresponding to the amount of depression of the vehicle driver's brake pedal 21 6 target rotation speed ^{Vfl *, Vfr *, Vrl *} , set the Vrr ^*, each Actual rotation speeds of wheels 3 to 6 Vfl, Vfr, V
rl, Vrr the respective target rotational speed ^{Vfl *, Vfr *, Vrl *} ,
The braking hydraulic pressures Pfl, Pfr, Prl, Prr of the respective hydraulic braking devices 13 to 16 are calculated so as to be Vrr ^*, and a series of braking control is performed to drive and control the electromagnetic switching valves 41 to 44, respectively. Next, FIG. 6 shows a control system diagram of the control circuit 30, and the control system of the braking circuit 30 will be described. Note that this control system is actually executed according to the control program shown in the flowchart of FIG. 9 described later, and does not show a hardware configuration.

As shown in the figure, to unlikely each wheel 3 6 of the target rotational speed ^{Vfl *, Vfr *, Vrl *} , Vrr * are set by the target rotational speed setting unit P1 that corresponds to the target rotational speed setting means M8. The integrator P2 is the set target rotational speed ^{Vfl *, Vfr *, Vrl *} , Vrr * and the actual rotational speed Vfl detected by the rotation sensors 7 to 10, Vfr,
The deviations Sfl, Sfr, Srl, and Srr from Vrl and Vrr are accumulated, and the accumulated values Zfl, Zfr, Zrl, and Zrr are obtained.

Next, the observer P3 receives the detected wheels 3 to 6 from each other.
Rotation speeds Vfl, Vfr, Vrl, and Vrr of each of the hydraulic brake devices 13 to 16 and the brake hydraulic pressures Pfl, Pfr, Prl, and P
rr and the internal state of the vehicle In the quantity determining unit P4, the calculated state variable quantity And the cumulative values Zfl, Zfr, Zrl obtained by the integrator P2,
Optimal feedback gain preset to Zrr And the hydraulic pressures Pfl and P of the hydraulic cylinders 21 to 24 are integrated.
Calculate fr, Prl, and Prr. The drive signal output unit P5 outputs drive signals Tfl, Tfr, Trl, Trr for the electromagnetic switching valves 41-44 corresponding to the calculated hydraulic pressures Pfl, Pfr, Prl, Prr of the hydraulic brake devices 13-16. It is a thing.

The configuration of this control system has been briefly described above. Next, the construction of a dynamic model by actual system identification, the design of the observer P3, and the optimal feedback gain How to give is explained.

First, we build a dynamic model of the vehicle height system.

FIG. 7 is a diagram in which the control system of this embodiment, that is, the system of four inputs and four outputs is described by transfer functions G1 (Z) to G16 (Z). Note that Z indicates Z conversion of the sampled value of the input / output signal, and G
1 (Z) to G16 (Z) have an appropriate order. Therefore the whole transmission It is represented by.

The method of system identification is introduced, for example, in Setsuo Sagara et al., "System Identification" (1981), The Society of Instrument and Control Engineers, etc. Here, the identification is performed by the least square method.

The vehicle is run under predetermined conditions, the brake hydraulic pressure Pfl is applied only to the hydraulic brake device 13 for the left front wheel 3, and the brake hydraulic pressure Pfl is changed. The rotational speed data of the left front wheel 3 at that time is repeated N times. To sample. Input data series {u (i)} = {Pfl (i)}, output data series {y (i)} = {Vfl (i))} (where i = 1, 2, 3
When expressed as N), the system can be regarded as one input and one output, and the transfer function G1 (Z) of the system is G1 (Z) = B (Z ^-1 ) / A (Z ^-1 ) ... (3) That is, G1 (z) = (b0 + b1 · z ⁻¹ + ... + bn · z ⁻¹ ) / (1 + a1 · z ⁻¹ + a2 · z ⁻² + ... + an ·
z− ⁿ ) (4) Here, z ⁻¹ is a unit transition operator and means z ⁻¹ · x (k) = x (k−1).

The transfer function G1 (z) of the system can be obtained by determining the parameters a1 to an and b0 to bn of the equation (4) from the input / output data series {u (i)}, {y (i)}. In system identification by the method of least squares, these parameters a1 to an, b0
~ Bn Is set to be the minimum. For example, when n = 2 and each parameter is calculated, the signal flow diagram of the system is as shown in FIG. 8, and the state variable amount is [x1 (k) × 2
(K)] Taking ^T , the state / output formula is Can be expressed as Therefore, it is regarded as a system with one input and one output. Becomes

In this way, the transfer functions G1 (Z) to G16
(Z), and system parameters for each Next, a method of designing the observer P6 will be described. There are Gopinas design methods in the design of the observer, and Katsuhisa Furuta and Akira Sano "Basic System Theory" (1978).
Although detailed in Corona, etc., this embodiment is designed as a finite set observer.

The observer P2 has the rotational speeds Vfl, V of the wheels 3 to 6 respectively.
fr, Vrl, Vrr, and hydraulic brake devices 13 to 16
The amount of state variables inside the vehicle from the brake hydraulic pressures Pfl, Pfr, Prl, Prr of Is estimated by the observer P2. The rationale for being able to do is in the following points. Now of Suppose you have configured it.

is there. By transforming from equations (1), (2), and (9), You can

Now, the system equation is identified by the method of least squares and is determined. The equation of state (1) and the output equation (2) are calculated. It can be transformed into a canonical form.

From equations (13), (14) and (15), And it is possible to design a finite set observer. Although this is a similar transformation, the correctness of control by the state equation is also guaranteed by this operation.

Above, the vector of the state equation (1) etc. obtained by system identification I designed the observer P3, but after that, I changed the output of this observer to Since the method to be obtained is detailed in, for example, “Linear System Control Theory” (supra), the detailed explanation is omitted here and only the result is shown.

For (k) and And the optimum control input that minimizes the following evaluation function J, that is, the drive condition of the brake hydraulic pressure generation unit 18. Obtaining (specifically, the brake hydraulic pressure of each hydraulic brake device 13 to 16) solves the control problem as the additional integral type optimum regulator for the main braking control system.

Shows the number of samplings when the control start time is 0. This is a so-called secondary type expression.

Is the solution. Incidentally, here, the meaning of the evaluation function J of the equation (19) means various quantities as the control input to the vehicle, that is, various quantities of the vehicle state as the control output while restricting the brake oil pressures Pfl, Pfr, Prl and Prr. , Here, the rotation speeds Vfl, Vfr, V of the respective wheels 3 to 6
Target value of rl and Vrr , I.e. the target rotation speed ^{Vfl *, Vfr *, Vrl *} , is intended attempts to minimize the deviation from Vrr ^*. The weighting of the constraint on each rotation speed Vfl, Vfr, Vrl, Vrr It can be changed by the value of. Therefore, the dynamic model, that Because it is required To obtain the optimum feedback gain by repeating the above simulation until the optimum control characteristics are obtained. Was asked.

As described above, the dynamic model of the braking control system of the vehicle is constructed by the system identification by the least square method, the design of the finite set observer, the optimal feedback gain. I explained the calculation of
Inside the control circuit 30, actual control is performed using only the result.

Therefore, the control actually performed by the control circuit 30 will be described below with reference to the flowchart of FIG. In the following description, the amount handled in actual processing will be denoted by the subscript (k), and the amount handled last time will be denoted by the subscript (k-1).

When the vehicle driver gives a braking instruction by depressing the brake pedal 21 while the vehicle is running, the CPU 52 starts the braking control process shown in FIG. 9 and performs this process until the brake pedal 21 is no longer depressed. Repeat.

When the process is started, step 100 is first executed to perform an initialization process for clearing flags, registers and the like used in the process execution described later. In the following step 100, the wheels 3 to 6 detected by the sensors are
Rotation speeds Vfl (k), Vfr (k), Vrl (k), Vrr
(K), the amount of depression of the brake pedal 21, the deceleration g of the vehicle
Enter (k).

In step 120, it is determined whether or not the flag F is cleared. If the flag F is in the clear state (indicating immediately after the main braking control is started), the process proceeds to the next step 130 and the vehicle speed Vs ( k) is calculated as an average value of the rotational speeds Vrl (k) and Vrr (k) of the left and right rear wheels 5 and 6. Then, the flag F is set in step 140, and the process proceeds to the following step 150.

On the other hand, when it is determined in step 120 that the value of the flag F is in the set state (in the case of the second and subsequent processes after the start of this control process), the process proceeds to the next step 160 and the vehicle body speed Vs (k) , Vs (k) ← Vs (k-), which has the vehicle speed Vs (k-1) obtained at the time of the previous processing and the elapsed time t therebetween, and the deceleration g (k) of the vehicle as parameters. 1) -g (k) · t is used for the calculation, and the process proceeds to step 150. The processes of steps 120 to 140 or steps 120 and 160 correspond to the vehicle body speed detecting means M2.

In step 150, the slip ratio S corresponding to the braking request of the vehicle body driver is set by using the map or the arithmetic expression in which the depression amount of the brake pedal 21 input in step 110 is used as a parameter, and the process proceeds to next step 170. To do. Then, at step 170, the target rotation speed Vfl of each of the wheels 3 to 6 is set using the set slip ratio S and the calculated vehicle body speed Vs as parameters.
^{(K) *, Vfr (k} ) *, Vrl (k) *, Vrr (k) *
Is set, and the process proceeds to the subsequent step 180.

In step 180, the set target rotational speed ^{Vfl (k) *, Vfr (} k) *, Vrl (k) *, Vrr
Deviations Sfl (k), Sfr (k), Srl (between (k) ^* and the actual rotation speeds Vfl (k), Vfr (k), Vrl (k), Vrr (k) input in step 110. k), Srr (k)
Is calculated, and the process proceeds to the next step 190. Then, in step 190, the deviations Sfl (k), Sfr obtained above are obtained.
(K), Srl (k), Srr (k) and accumulated deviation values Zfl (k), Zfr (k), Zrl (k), Z up to the previous process.
Accumulated values Zfl (k) and Zfr by adding rr (k) and
Calculation processing of (k), Zrl (k), and Zrr (k) is executed. This process corresponds to the integrator P2 shown in FIG. Further, step 170 is the slip ratio setting means M7, and step 180 is the target rotation speed setting means M8.
They correspond to (target rotation speed setting unit P1 in FIG. 6), respectively.

In the following step 200, the value obtained by the method described above and stored in the ROM 53 in advance is stored. Actual rotation speed Vfl (k), V read at step 110
fr (k), Vrl (k), Vrr (k) and the previous time [X1 (k-1) X2 (k-1) ... X6 (k-1)] and the brake hydraulic pressures Pfl (k-1) and Pfr (k-1) of the hydraulic brake devices 13 to 16 obtained last time. , Prl (k-1), Vrr (k
-1) and a new state estimator from Is calculated. This processing corresponds to the observer P3 in FIG. 6, but in this embodiment, the observer P3 is configured as a finite settling observer as described above. Is calculated.

In the following step 210, the state estimation amount obtained in the above step 200 And the cumulative value Zfl (k) obtained in step 190,
Zfr (k), Zrl (k), Zrr (k) and optimum feedback gain stored in advance in the ROM 53 By vector multiplication of Thus, the processing for obtaining the brake oil pressures Pfl (k), Pfr (k), Prl (k), Prr (k) of the respective hydraulic brake devices 13 to 16 is executed. This corresponds to the feedback amount determination unit P4 in FIG.

Next, at step 220, the hydraulic brake devices 13 to 1
Brake hydraulic pressure of 6 Pbr hydraulic pressure Pfl obtained above
(K), Pfr (k), Prl (k), Prr (k) drive signals Tfl (k), Tfr (k), Trl (k), Trr for driving the electromagnetic switching valves 41 to 44. (K)
The following equation Tfl (k) = T · (Pfl (k) −Pa) / (Pb−Pa) Tfr (k) = T · (Pfr (k) −Pa) / (Pb−Pa) Trl (k) = T -(Prl (k) -Pa) / (Pb-Pa) Trr (k) = T * (Prr (k) -Pa) / (Pb-Pa), and it transfers to step 230.

In the above equation, Pa represents the oil discharge pipe pressure (atmospheric pressure), Pb represents the oil supply pipe pressure, and T represents the preset control cycle of the electromagnetic switching valves 41 to 44.

That is, in the present embodiment, the drive control of each of the electromagnetic switching valves 41 to 44 is configured to be executed by so-called duty control. For example, as shown in FIG. 10, when a drive signal is output within a predetermined time T for Tx time, The average hydraulic pressure P of the hydraulic brake device is P = (Tx / T) (Pb-Pa) + Pa, and if the average hydraulic pressure P is the target hydraulic pressure, the driving time Tx per predetermined time T is given by the following equation Tx = T. (P- Pa) / (Pb-Pa).

Next, at step 230, the drive signals Tfl (k), Tfr (k), Trl (k), and Trr (k) thus obtained are output to the electromagnetic switching valves 41 to 44, and the routine proceeds to step 240. Then, in step 240, a process of incrementing k indicating the number of times of sampling by 1 is performed, and the process proceeds to step 110 again.

By controlling the brake hydraulic pressure during vehicle braking in this way, the vehicle can be decelerated or stopped with a slip ratio corresponding to the instruction of the vehicle driver during vehicle braking, and the vehicle is stopped at the shortest distance during sudden braking. Will be able to. Therefore, if the braking device of the present embodiment is mounted on a vehicle, the running stability and safety during vehicle braking can be improved very well.

Here, in the above-described embodiment, the braking device of the present invention is realized by completely separating the brake 21 and the brake oil pressure generation unit 18, but it is also conceivable that the brake oil pressure generation unit 18 may malfunction. For this reason, it is desirable that the brake hydraulic pressure is generated by the depression of the brake pedal 21 at the time of failure, and the brake hydraulic pressure is transmitted to each of the hydraulic brake devices 13 to 16.

In the above embodiment, the target rotation speed V of each wheel 3 to 6 is set.
Although fl, Vfr, Vrl, and Vrr have been described as being the same values obtained by using the vehicle body speed Vs and the slip ratio S as parameters, for example, the target rotation of the left and right wheels depending on the steering angle of the steering wheel or the like. If you set the speed to a different value,
The braking of the vehicle when traveling on a sharp curve can be controlled more precisely, and the safety is further improved.

[Effects of the Invention] As described above, in the vehicle braking control device of the present invention, the system related to vehicle braking estimated from the braking pressure of the braking member that serves as a control input and the rotation speed of each wheel that serves as a control output. Using the state variable amount indicating the dynamic internal state, the integrated value or the cumulative value of the deviation between the rotation speed of each wheel and the target rotation speed, and the preset optimum feedback gain, the rotation speed of each wheel is calculated. The brake pressure for controlling to the target rotation speed is determined, and the brake pressure adjusting member is drive-controlled.

Therefore, according to the present invention, the rotation speed of each wheel can be quickly converged to the target speed without a response delay. Further, in particular, in the present invention, since the dynamic internal state of the system relating to the braking of the vehicle is estimated as the state variable amount and the brake hydraulic pressure as the feedback amount is determined, braking of each wheel is performed as in the conventional device. The brake pressure of each wheel can always be optimally controlled without the control becoming unstable due to variations in the system or changes with time. Therefore, if this braking control device is used, the traveling stability and safety during vehicle braking can be improved very well.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of the present invention, FIG. 2 is an explanatory view for explaining a conventional anti-skid device, FIGS. 3 to 10 show an embodiment of the present invention, and FIG. 4 is a schematic configuration diagram showing an overall configuration of a braking control device of an embodiment, FIG.
FIG. 7 is a hydraulic system diagram showing the configuration of the brake hydraulic pressure generating member 18, FIG. 5 is a block diagram showing the configuration of the control circuit, FIG. 6 is a control system diagram showing the control system of this embodiment, and FIG. 7 is a control system. 8 is a block diagram for explaining the identification method of the above, FIG. 8 is a diagram showing an example of a signal flow diagram used in obtaining a system parameter from a transfer function, and FIG. 9 is a control program for braking control of this embodiment. The flowchart and FIG. 10 are graphs for explaining the drive signal of the electromagnetic switching valve. DESCRIPTION OF SYMBOLS 1 ... Vehicle 3,4,5,6 ... Wheel 7,8,9,10 ... Rotation sensor 13,14,15,16 ... Hydraulic brake device 18 ... Brake hydraulic pressure generating part 20 ... Stepping amount sensor 21 ... Brake pedal 22 ... Acceleration sensor 41, 42, 43, 44 ... Electromagnetic switching valve

Claims (1)

[Claims] 1. A rotation speed detecting means for detecting a rotation speed of each wheel of a vehicle, a brake pressure adjusting means for adjusting a brake pressure transmitted to a braking member of each wheel according to a given drive signal, and a vehicle. Target rotation speed setting means for setting the target rotation speed of each wheel, and determining the brake pressure of the braking member for controlling the detected rotation speed of each wheel to the set target rotation speed of each wheel. A braking control means for outputting a drive signal according to the brake pressure to the brake pressure adjusting means, the braking control means for the vehicle comprising: Using the parameters preset based on the dynamic model, the rotation speed of each wheel detected by the rotation speed detecting means and the brake pressure adjusting means adjusted by the brake pressure adjusting means. A state observing section that estimates a state variable amount of an appropriate order that represents a dynamic internal state of the system from the brake hydraulic pressure of the braking member, and a rotation speed detected by the rotation speed detecting means for each wheel. An accumulator that calculates a deviation from the target rotation speed set by the target rotation speed setting means and calculates an integrated value or an accumulated value of the deviation, the estimated state variable amount, and the calculated integration value. Alternatively, a brake pressure determining unit that determines the brake pressure of the braking member from a cumulative value and a preset optimum feedback gain, and an additional integral type optimum regulator including: Braking control device.