JPS6167665A - Car steering controller - Google Patents

Abstract

PURPOSE:To modify the motion performance easily by obtaining a target motion variable of target car different from that of one's own car and operating the target steering angles of front and rear wheels to realize said target level as the motion variable of one's own car. CONSTITUTION:In accordance to a motion formula employing features of target car different from those of one's own car, the target motion variable M of car corresponding with detected values thetas and V from steering amount detecting means 100 and car speed detecting means 101 is obtained through target motion variable operating means 102. Then, on the basis of said target variable M and the features of one's own car, target steering angle operating means 103 will obtain the target front wheel steering angle deltaf and the target rear wheel steering angle deltar. On the basis of said values deltaf, deltar, front and rear steering means 104, 105 will control steering of front and rear wheels.

Description

Detailed Description of the Invention (Industrial Utilization Public Funds) The present invention can be applied to a steering system for a four-wheel steering vehicle capable of steering front and rear wheels, and is particularly applicable to the steering system for a four-wheel steering vehicle capable of steering front and rear wheels. The present invention relates to a vehicle steering control device that can freely control the vehicle.

(Prior art) A conventional vehicle equipped with a mechanical link type steering device is configured to steer the front wheels in response to the amount of turning of the steering wheel, and the interlocking variables associated with steering are , is uniformly determined by the vehicle specifications of the vehicle, and the driving performance is unique to each vehicle type.

(Problems to be Solved by the Invention) However, as described above, in conventional vehicles, in order to change the driving performance, it is necessary to change the vehicle specifications.
For example, it has been difficult to make a sedan car have the driving performance of a sports car.

This is because the vehicle specifications of a sports car are determined by the car/body structure and tire characteristics of the sports car, so the car ends up with a body structure that cannot be called a sedan car.

Furthermore, in the case of competition vehicles (rally cars), both acceleration performance and steering response are required to be excellent.
In order to improve acceleration performance, the engine displacement is increased, which increases the vehicle weight, resulting in a decrease in steering response. Therefore, if an attempt is made to improve the steering response by reducing the vehicle body size and reducing the yaw inertia, the large engine cannot be mounted on the tower and the acceleration performance cannot be improved.

As described above, conventional vehicles in which the driving performance of the vehicle is uniformly determined by the vehicle specifications have various disadvantages.

(Means for Solving the Problems) In order to solve the above problems, the present invention, as shown in FIG. 101 and
1i of a vehicle using vehicle specifications different from the own vehicle specifications
! A motion variable target value calculation means 10s+ calculates a motion variable target value M of the vehicle corresponding to the steering wheel steering amount θ5 and the vehicle iV using the imperial equation, and calculates the motion variable target value calculated based on the vehicle specifications of the host vehicle. , comprises a steering angle target value calculation means IQ3 for calculating a front wheel steering angle target value δf and a rear wheel steering angle target value for realizing the motion variable target value M, and roughly calculates the determined front wheel steering angle target value δf. The vehicle is equipped with a front wheel steering means 104 for steering the front wheels according to the determined rear wheel steering angle target value, and a rear wheel steering means 105 for steering the rear wheels according to the obtained rear wheel steering angle target value.

(Function) The motion variable target value M obtained by the motion variable target value calculation means 102 is a value different from the interlocking variable of the own vehicle,
For example, in the case of a sedan, the motion variables of a Smets car are set as target values.

Then, steering angle target values for the front and rear wheels are determined so as to realize the determined motion variable target value M as a motion variable of the own vehicle, and the wheels are steered to this steering angle target value.

Therefore, for example, even if the vehicle body structure is of a sedan type, it is possible to provide the same driving performance as a sports car.

(Example) The configuration of one embodiment of the present invention is shown in FIG.

The microcomputer 1 inputs the vehicle speed V detected by the vehicle speed sensor 8 and the steering tθ8 of the steering wheel 8 detected by the steering wheel steering amount sensor 2, and calculates a motion variable target value and calculates the front wheel steering angle and front wheel turning. The device 4 is a device that performs steering control of the front wheels 9 and 10 based on the data of the front wheel steering angle target value δf given from the microcomputer 1. This device controls the steering of the rear wheels 11 and II based on the data of the rear wheel steering angle target value δ1.

Front wheel9. It is the hydraulic steering devices 6 and 7 that actually steer the lO and the rear wheels 11,12.

The front wheel steering means, the rear wheel steering device 5, and the hydraulic steering device 6, 7 are configured as shown in FIG. 3, for example.

Hydraulic steering device 1Q? is two pistons 8
The wheels are rotated by moving the shirt 31, which is equipped with Z and 33 and whose both ends are connected to tie rods (shown in the diagram), in the axial direction by creating a difference in the working pressure of the left and right hydraulic chambers 34 and 35. Do the rudder.

In addition, a repulsion play (38.3°9) biased in left and right opposite directions by a spring 36 is loosely fitted into the shaft 31 in the center shaft 37, and this is attached to the left and right hydraulic chambers 34.85. This is for returning the shaft 81 to its original neutral position when the hydraulic oil is removed.

The front/rear wheel steering system R114.5 uses solenoid driver 2.
1, a control pulp 22, an oil pump 26, and an oil tank 27.

The Huntroll pulp 22 is equipped with a hydraulic staking ring device rr.
t6, ? Leading to the left and right hydraulic chambers 34.35 i:'
It is equipped with circuits 28 and 29, and a spool pulp 25 that adjusts the flow of hydraulic oil flowing into these oil passages 28 and 29. The left and right ends of this spool pulp 25 are '! ! E.R.
1 solenoid 23.24, and moves in the axial direction depending on the magnitude of the magnetic force of the electromagnetic slide/id 23.24 to adjust the pressure applied to the left and right hydraulic chambers a4.85.

The solenoid driver 21 receives front and rear wheel steering angle target values if given from the microcomputer 1.

A current signal proportional to
B, supplies to 2+. In this case, will the current be applied depending on the steering direction of the wheel? The fcBi solenoid is controlled by switching between left and right.

FIG. 4 is a flowchart showing the processing executed by the microcomputer l. The operation of this embodiment will be explained below along with the explanation of this flowchart.

The process shown in FIG. 4 is repeatedly executed every predetermined time period Δ, and initialization is performed when the ignition switch is turned on and power is supplied.

In the process of step 41, the data of the steering wheel steering amount θ8 and the data of the vehicle speed V input from the steering wheel steering amount sensor 2 and the vehicle speed sensor 8 to the microcomputer 1 are read.

In the process of step 42, the target vehicle specifications stored in the memory in advance are read out. As the target vehicle specifications, vehicle specifications of a vehicle (this is referred to as a "target vehicle") different from the vehicle (own vehicle) on which the present example device is mounted are used. For example, when the own vehicle is a sedan car, the vehicle specifications of a sports car are Jf7 as the target vehicle specifications. That is,
The target vehicle is a sports car.

In this embodiment, the following vehicle and both specifications are used as target vehicle specifications.

Yaw inertia of the target vehicle M: Vehicle weight of the target vehicle L: Wheel pace of the target vehicle LFl 'Distance between the target vehicle's front axle and center of gravity LR: Distance between the target vehicle's rear axle and center of gravity IKl' Target #, inertia around the kingpin Ks□: fQ +j [both steering stiffness DK□: #*steering thread viscosity coefficient ξ of both
, : Target vehicle's trail number: Target vehicle's steering gear ratio, □: Target vehicle's front wheel cornering power KR1'
Cornering power of the rear wheels of the target vehicle ~ Then, in the next step 48, the target motion variables (in this embodiment, yaw angular acceleration and centripetal G (centripetal acceleration)) are determined using the target vehicle specifications. An operation is performed. This calculation is performed according to the following formula.

Kx'fx = 'IK31(θS-'lδfl)-
DKl"fl""ξICFt---(1)
M (V "PV) = 20F, +2OR, ---
f2) 1.1 工z1ψl:""FICFl-2LRIORI
−−−+31βFl ”δf1−(9+Ly divination)
/ V ---f41βR1= −(1, −
LR1'P1) / "I---(5
1'Fl = KFlβF1 --- (6) CR□ =
KR engineering β8,--one digit) π... ψ=ψ1-- (8) YG =: "1+ψ, V
---(9) Here, δfl' Front wheel steering angle of the target vehicle (assuming that the target vehicle is a two-wheel steered vehicle) ψ, : Yaw rate ψ of the target vehicle, : Yaw angular acceleration y of the target vehicle: Lateral speed y of the target vehicle: Lateral acceleration βFl of the target vehicle 'Slip angle βR of the front wheels of the target vehicle: Side slip angle CFl of the rear wheels of the target vehicle 'Cornering force OR of the front wheels of the target vehicle
Y: Cornering force of the rear wheels of the target vehicle φ: Yaw angular acceleration giant value YG: Centripetal G target value.

The above equations (1) to (3) are equations of motion for the target vehicle. To solve these equations, four integral operations are required for each Δ. This integral operation is, for example, A(t+Δt
)=A(t)+Δt-A(t), or the Runge-Kutta method, an appropriate integration method is used depending on the required integration precision.

In this way, the obtained yaw angle ff0t4 degree target value ψ and centripetal G target value YG are determined by the steering wheel steering amount θ8 and the vehicle speed V
These are the yaw angular acceleration and centripetal G of the target vehicle corresponding to the target vehicle, and the aim of this embodiment is to make the own vehicle realize the motion variables of the vehicle that are different from those of the own vehicle.

Next, in the process of step 44, the vehicle specifications of the own vehicle stored in the memory in advance are read out. In this embodiment, the following vehicle specifications are used.

Engineering Zs' Yaw inertia of own vehicle M3: Vehicle weight and weight of own vehicle: Wheel pace of own vehicle? , F, : Distance between the front axle and the center of gravity of the own vehicle LR2' Distance between the rear axle and the center of gravity of the own vehicle KF2 'Cornering power of the front wheels of the own vehicle KRi'
Cornering power of the rear wheels of the own vehicle Then, in the next step 45, based on the vehicle specifications of the own vehicle and obtained in step 43, the steering angle target value a of the front and rear wheels of the own vehicle is determined.
An operation is performed to obtain f, J. This operation is performed according to the following formula.

OFg = 沁(M2LRfiYG+工Z!φ)
-(101"" = 2L "s"y!YG-ENGz!
φ) ---Qυβmouth='Fl /KFl
=-(2)・βR11” OR1/
KRl = -αj where: Cornering force of the front wheel of CFz' own 1f [0R1
1' Cornering force βFg of the rear wheels of the own vehicle 'Slip angle βRffi of the front wheels of the own vehicle' Side slip angle ψ of the rear wheels of the own vehicle, : Yaw rate y of the own vehicle, : Lateral speed of the own vehicle.

The front/rear wheel steering angle eye friction value δf + 'r obtained by such calculation is determined by the process of the next step 46.
Each is input into the front wheel steering bag [4] or the rear wheel steering bag [5.

The front wheel steering bag RTT4 and the rear wheel steering device 5 supply the hydraulic pressure necessary to steer the front wheels 9, 10 or the rear wheels 11, 12 to a given steering angle target value δf or δ1 using a hydraulic steering device. 6.7, and as a result, the front wheel 9
, 10 and the rear wheels 11, 12 are steered.

Through the above operations, the yaw angular acceleration of the host vehicle and the centripetal G of the host vehicle become the same values as those of the target vehicle, and as a result, the host vehicle has the same dynamic performance as the target vehicle. That is, for example, if your car is a sedan car,
If the target vehicle is a sports car, the vehicle body structure, etc. of the own vehicle can remain the same, and the driving performance can be made to be that of a sports car.

Furthermore, in reality: ・We specifically show how much change in exercise performance can be obtained.

Now, the vehicle (own vehicle) equipped with the device of this embodiment has a displacement of zo
oocc, yaw inertia I, = 240 kgf-m-
A vehicle with the same displacement and yaw inertia Iz = 120119f-m-8'' is set as the vehicle s2 and as the target vehicle.

It is assumed that other vehicle specifications are the same between the host vehicle and the target vehicle.

Figure 5 shows the above settings, j + (?EV = s o
b, /h Notoki, 120° steering wheel Q, I
FIG. 6 is a diagram showing a change in yaw rate when the yaw rate is changed in steps between 3 and 3, and FIG. 6 is a diagram showing a change in centripetal G in a similar state.

In addition, FIGS. 7 and 8 show the vehicle speed V with the above settings:
I Q OKm/h),! : *1±80°F)
A/Changes in late gain/steering amount and centripetal G/steering amount when steering is applied in a sinusoidal manner and the steering frequency is varied from 0.1 to 2 Hz (these are referred to as "frequency response") In addition, the characteristics shown by the solid line in the above-mentioned FIGS. This shows the characteristics when a mechanical link type steering device is installed.

As shown in FIGS. 5 and 6, when this first example device is mounted on a tower, the steering response is significantly improved compared to the conventional one. For example, the occurrence of yaw rate is 90% of steady state.
By the time it reaches , the conventional OJ7 B has been reduced to about 0.178.

Furthermore, as shown in FIGS. 7 and 8, when the device of this embodiment is mounted on a tower, the frequency response performance is also improved compared to the conventional one. The effect of improving frequency response performance is particularly large when the frequency is high. At the same time, phase delay can also be reduced.

In addition, in the above embodiment, an example was shown in which a specific vehicle (for example, a sports car) is set as the target vehicle and control is performed using the vehicle specifications of the target vehicle. Instead of setting the target vehicle as the target vehicle, a low-altitude vehicle with the ideal or required maneuverability may be used as the target vehicle.For example, in a rally car, a large engine is installed and the steering response is improved. It is also possible to improve sex.

Furthermore, it is also possible to set a midship vehicle as the target vehicle, and even a vehicle that is not a T-radish type vehicle can be given the same driving performance as a midship vehicle.

Furthermore, the vehicle specifications of the target vehicle may be stored and included, and the target vehicle may be freely selected according to the driver's preference.

Further, in the above embodiment, an example was shown in which the yaw angular acceleration and the centripetal G are determined as the motion variable target values, but motion variables other than these, such as cornering force and sideslip angle, may be determined as the target values. Furthermore, instead of two target values, there may be one, or three or more target values.

(Effects of the Invention) As explained in detail above, the present invention has the advantage that, whereas in conventional vehicles, the dynamic performance is determined by the JE and JE specifications of the vehicle, it is determined by the vehicle specifications. The dynamic performance, which is different from the dynamic performance, can be freely changed without changing the vehicle body structure or the like.

This makes it possible, for example, to provide a normal vehicle with the same dynamic performance as a mid-engine vehicle, or to provide a rally vehicle with high steering response even though it is equipped with a large engine.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of the present invention, FIG. 2 is a configuration diagram of an embodiment of the present invention, and FIG. 8 is a front wheel steering device, a rear wheel steering device, and a hydraulic steering device shown in FIG. 2. 1441m is a flowchart showing the processing executed by the microcomputer in FIG. 2, and FIGS. 5 to 8 are characteristic diagrams specifically showing the steering response of a vehicle equipped with the device of the present invention. It is. 100...Handle steering amount detection means 101...Vehicle speed detection means 102...Motion variable target value calculation means 10+1...Steering angle target value calculation means 1G4...Front wheel steering means 105...Rear wheel rotation Rudder means 1...Microcomputer 2...Handle steering amount sensor 8...Vehicle speed sensor 4...Front wheel steering device 5.
... Rear wheel steering device 6.7 ... Hydraulic steering device 8 ... Steering handle 9.10 ... Front wheel 11.12 ... Rear wheel patent applicant Nissan Motor Co., Ltd. Figure 1 Figure 3 Figure 4 Figure 5 Time (S) Figure 7

Claims (1)

[Claims] 1. A steering wheel steering amount detecting means for detecting a steering amount of a steering wheel, a vehicle speed detecting means for detecting a vehicle speed, and a motion of a vehicle using vehicle specifications different from vehicle specifications of the own vehicle. a motion variable target value calculation means for calculating a target value of a motion variable of the vehicle corresponding to the detected steering wheel steering amount and vehicle speed using an equation; , steering angle target value calculation means for calculating target values of a front wheel steering angle and a rear wheel steering angle to realize the determined motion variable target value, and steering the front wheels to the determined front wheel steering angle target value. A vehicle steering control device comprising: a front wheel steering device; and a rear wheel steering device that steers the rear wheels to the determined rear wheel steering angle target value.