JPS61175177A - Steering angle control device for vehicle - Google Patents

Abstract

PURPOSE:To widen the width of maneuverability control by dividing a yawing motion and a lateral motion, setting their target values separately, and performing the steering angle control of wheels so as to realize the target values. CONSTITUTION:Front and rear wheel steering devices 4, 5 are constituted with a solenoid driver 21, a control valve 22, and an oil pump 26. The control value 22 is provided with oil paths 28, 29 communicated to the right and left hydraulic chambers 34, 35 of hydraulic steering devices 6, 7 and has a spool valve 25 adjusting the operating oil flowing into these oil paths 28, 29. The solenoid driver 21 feeds an electric current signal proportional to the front and rear steering angle target values deltaF, deltaR provided by a microcomputer 1 to one of the right and left solenoids 23, 24, thereby the spool valve 25 is switched, and steering devices 6, 7 are operated.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a steering angle control device for a vehicle that can freely control the dynamic performance of a vehicle during steering, and in particular, to a steering angle control device for a vehicle that can freely control the dynamic performance of a vehicle during steering, and in particular, to The present invention relates to a steering angle control device for a vehicle that appropriately controls yawing motion and lateral motion.

(Conventional Technique) Vehicles equipped with conventional mechanical link steering devices are configured to steer the front wheels in response to the amount of steering from the steering wheel, and the dynamic performance associated with steering is dependent on the vehicle's The tI:W is uniformly determined depending on the specifications, and the dynamic performance is unique to each vehicle type.

On the other hand, the applicant of the present application first assumed a target vehicle model provided in Japanese Patent Application No. 1983, and based on the vehicle specifications and equation of motion regarding the target vehicle model, the applicant proposed a motion corresponding to the steering wheel turning amount and vehicle speed. The target value of the variable, that is, the kinematic variable value representing the kinematic performance exhibited by the target vehicle model, is determined, and the wheels of the own vehicle (front wheels and We are proposing a device that controls the steering angle of the rear wheels.

In other words, if you use this device, for example, even if your vehicle is a sedan type vehicle, if you set the target vehicle model to a sports car type vehicle, it will be possible to create a sports car model even though the body structure etc. are of the sedan type. It is possible to freely control exercise performance, such as maintaining exercise performance.

(Problems to be Solved by the Invention) By the way, the inventors of the present application discovered the following improvement point while conducting further research on the above device.

That is, since the apparatus according to the above-mentioned prior application sets only one target vehicle model, the target values of the motion variables found by calculations regarding this target vehicle model have a correlation. For example, when determining target values for yaw rate and lateral acceleration as motion variable target values, even if it is attempted to control only the yaw rate, the lateral acceleration will also change as the yaw rate changes.

For this reason, the range of motion performance control becomes narrow, and more flexible control cannot be performed.

(Means for Solving the Problems) In order to solve the above problems, the present invention includes means shown in FIG.

The yawing movement target value calculation means 102 calculates the steering wheel steering angle θ8 detected by the steering wheel angle detection means 100 and the vehicle speed detection means 101 by calculation regarding a first target vehicle model having a preset desired movement performance. The lateral motion target value calculation means 108 calculates the target value A of the yawing motion corresponding to the vehicle speed V detected at A target value Y in the lateral direction corresponding to the steering wheel steering angle θ8 and the vehicle speed V is determined.

The steering angle target value calculating means 104 calculates a target value (■) of the wheel steering angle of at least one of the front wheels or the rear wheels from the above-mentioned eyeing movement target value A, the lateral movement target value Y1, and the vehicle specifications of the host vehicle. demand.

Then, the wheel steering means 105 controls the wheel steering angle target value 7.
Then, the corresponding front and rear wheels are steered.

(Function) The yawing motion target value calculation means 102 and the lateral motion target value calculation means 108 separately determine the yawing motion target value 7 and the lateral motion target value Y based on different target vehicle models. A steering angle target value 1 of the wheels is determined in order to realize the motion variable target values 7 and Y in the own vehicle, and the wheels are steered to this steering angle target value ■.

Therefore, the host vehicle exhibits the same dynamic performance as the first target vehicle model with respect to yawing motion, and the same dynamic performance as the second target vehicle model with respect to increasing direction motion. Moreover, since the yawing movement target value 7 and the lateral movement target value Y have no correlation, they can be freely controlled separately and independently.
Increased freedom of control.

(Example) FIG. 2 shows the configuration of an embodiment of the present invention.

The microcomputer 1 inputs the vehicle speed V detected by the vehicle speed sensor a and the steering angle θS of the steering wheel 8 detected by the steering wheel angle sensor 2, and calculates the motion variable target value and calculates the front wheel steering angle target value T7. Then, a rear wheel steering angle target value TR is calculated.

The front wheel steering device 4 controls the front wheels 9, 9, and 9 based on the data of the front wheel steering angle target value TF given from the microcomputer 1.
Similarly, the rear wheel steering device 5 performs steering control of the rear wheels 11 and 12 based on the data of the rear wheel steering angle target value TR given from the microcomputer 1. It is a device.

It is the hydraulic steering devices 116 and 7 that actually steer the front wheels 9, 10 and the rear wheels 11t12.

The front wheel steering device 4, the rear wheel steering device 5, and the hydraulic steering device 6. For example, the structure is as shown in FIG.

Hydraulic steering device6. There are two pistons 82
．． The wheels are steered by moving a shaft 81 having a shaft 88 connected at both ends to tie rods (shown in the figure) in the axial direction by creating a difference between the working oil pressures of the left and right hydraulic chambers 34,85.

In addition, in the center chamber 87, repulsion plays (88, 89) biased in opposite left and right directions by a spring 86 are loosely fitted onto the shaft 81, which actuate the left and right hydraulic chambers 84,35. This is for returning the shaft 81 to its original neutral position when the oil pressure is removed.

The front and rear wheel steering devices 4 and 5 are composed of a solenoid driver 21, a control valve 22, an oil pump 26, and an oil tank 2.

The hunt roll valve 22 is connected to the hydraulic steering device 6
．． Oil passages 28 and 29 leading to the left and right hydraulic chambers 34 and 85 of the
A spool valve 25 is provided to adjust the amount of hydraulic oil flowing into these oil passages 28 and 29. This spool valve 25 has electromagnetic solenoids 28 and 24 at the left and right ends.
It is loosely fitted into the left and right hydraulic chambers 84, and moves in the axial direction depending on the magnitude of the magnetic force of the electromagnetic solenoids 28 and 24.
Adjust the amount of hydraulic oil given to 35.

The solenoid driver 21 sends a current signal proportional to the front/rear wheel steering angle target value 11FF"H given from the microcomputer 1 to either the left or right electromagnetic solenoid 28.24.
supply to. In this case, control is performed by switching the electromagnetic solenoid that applies current to the left or right depending on the steering direction of the wheels.

FIG. 4 is a flowchart showing the processing executed by the microcomputer 1. 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 angle θS and the data of the vehicle speed V, which are input to the microcomputer 1 from the steering wheel steering angle sensor 2 and the vehicle speed sensor 8, are read.

Next, in the process of step 42, vehicle specifications regarding the first target vehicle model (hereinafter referred to as "first target vehicle specifications") stored in advance in the memory are read out.

The first target vehicle specifications are obtained by assuming a vehicle having target characteristics regarding yawing motion, and storing the vehicle specifications of this assumed vehicle in a memory.

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

E: Yaw inertia I of the first target vehicle Mo: Body rental of the i-th target vehicle L7□: Distance between the front axle and center of gravity of the first target vehicle LR1" Distance between the rear axle and center of gravity of the first target vehicle N□ : to the steering gear ratio of the first target vehicle! Using the specifications, a calculation is performed to obtain a target value for the yawing movement (in this embodiment, the target value of the yaw rate and the yaw angular acceleration i:).This calculation is performed according to the following formula.

Ml (Vyl “PIV)” 20yl
+ 20RI ”・・”” (') 工, □P□==
2 L, 10. Knee 2” RI CR1・・・・・・
...(2)'IFI =KFl 4L-(vyl
” LIFI P,)/V
)'R1="" KRl (vyl -LRl 5',
)/V −−−−−−−−−−−(4) P =
PI ” song---------(
5) To = Yu, ・・・・・・
...(6) Here, ? : Yaw rate P0 of the first target vehicle = Yaw angular acceleration of the first target vehicle ■, □: @1 Speed of the target vehicle in the y-axis direction ■9, : Side slip acceleration in the y-axis direction of the first target vehicle C Ayu: First target Front wheel cornering force CR of the vehicle: This is the rear wheel cornering force of the first target vehicle.

Equations (1) and (2) above are equations of motion for the first target vehicle, and to solve these equations, two integral operations are required for each Δ. An appropriate integration method is used depending on the required integration precision, such as the rectangular integration method expressed by A(t+Δt)=A(t)+Δt−5(1), or the Runge-Kutta method.

During the above calculation, an equation of motion regarding lateral motion is also calculated, but since this first target vehicle is a target vehicle regarding yawing motion, the variables of lateral motion (vy□, ty□ ) is not used in the calculation of the steering angle target value T7, which will be described later.

Next, in the process of step 44, vehicle specifications regarding the second target vehicle model (hereinafter referred to as "second target vehicle specifications"), which are also stored in advance in the memory, are read out. The second target vehicle specifications are based on the assumption that a vehicle has target characteristics regarding lateral motion, and the vehicle specifications of this assumed vehicle are stored in the memory.

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

Work 2□: Yaw inertia M2 of the second target vehicle: Body mass LIFI of the second target vehicle! ! 'Distance L between the front axle and center of gravity of the second target vehicle
II 'Distance N between the rear axle and the center of gravity of the second target vehicle: Second
Target vehicle steering gear ratio KIF! 'The cornering power of the front wheels of the second target vehicle KRil! 'The cornering power of the rear wheels of the second target vehicle.Then, in the process of the next step 45, the target value of the lateral movement (in this example, the target value of the lateral acceleration α) is calculated using the second target vehicle specifications. 10,000). This calculation is performed according to the following formula.

M2<? , ＋? , v ) = 20. , +2
0R,・・・・・・・・・・・・(7) Engineering Zg '2
:2LIHC? 2°-2LR2CR1°----
---- (8) CR1= -KRz (Vys -L
ua '/'*)/V "・"...α groan a
= Vys + p 2 V ””
Song (11) where: Extra: Yaw rate of the second target vehicle P2: Yaw angular acceleration of the second target vehicle V: Speed of the second target vehicle in the y-axis direction Chi2: Side slip of the second target vehicle in the y-axis direction Acceleration C72
: Front wheel cornering force of the second target vehicle CR2'' is the rear wheel cornering force of the second target vehicle.

Equations (7) and (8) above are equations of motion for the second target vehicle, and are subjected to the same integral calculation as the equations of motion (1) and (2) for the first target vehicle.

During the above calculation, the equation of motion regarding the yawing motion is also calculated, but since this second target vehicle is a target vehicle regarding the lateral movement, the variable (P1*Pg ) is not used in the calculation of the steering angle target value δa, which will be described later.

In this way, the present embodiment calculates the yaw rate target value -, the yaw angular acceleration target value 11, and the lateral acceleration target value i from the first target vehicle and the second target vehicle, which have mutually independent motion performance. , the target value for the yawing motion (-1V) and the target value for the lateral motion (7i) are independent and have no correlation with each other.

Next, the processing in steps 46, 47, and 48 includes the target values P of the motion variables obtained from the separate target vehicles as described above.
, P and α are controlled as the motion characteristics of the own vehicle by controlling the front and rear wheel steering angles of the own vehicle (vehicle equipped with this embodiment).

That is, in the process of step 46, the vehicle specifications of the own vehicle stored in the memory in advance are read out, and the process is performed in step 4.
Through the process in step 7, the vehicle specifications of the own vehicle and the above motion variable target value P are determined.
, Pyα, the front and rear wheel steering angle target values J, , JR
is determined and outputted to the front wheel steering device @4 and the rear wheel steering device 5 in the process of step 48.

The vehicle specifications of the own vehicle read out in step 46 are shown below.

Engineering 2. : Own vehicle's yaw inertia M, : Own vehicle's body mass LA, : Distance between own vehicle's front axle and center of gravity LR8' Distance between own vehicle's rear axle and center of gravity, : Own vehicle's wheel pace KIP8: Cornering force of the front wheels of own vehicle KR8'
Cornering force of the rear wheels of your vehicle and step 4
The operation executed in &7 is as follows.

+y8=α−PV Song...Song/(
b) Vya = completedvy8a t
−−−−−−−−−−−03) CI'8=
('8LR8α Juku, -) ・・・・・・・・・・・・
(2L barrel.

CR8=21. ('8LFISα-I2.W
> −−−−−−−−−−−(15) 17g =
CIF5/KF8 ・・・・・・
...06) βR8= ORa/KR8...
・・・・・・α′I)su=βIFg”(vya−L
731')/V...JR)TR-β
Re + (Vy, -LR,?) /v ・-
-----------(19) Where, ■, 3: Speed of the own vehicle in the y-axis direction *y8: Internal sliding acceleration of the own vehicle in the y-axis direction 'IF8' Front wheel cornering power of the own vehicle CRB 'My car's rear wheel cornering power β? 3: Side slip angle of the front wheels of the own vehicle βRa 'This is the sideslip angle of the rear wheels of the own vehicle.

In the above calculation, the steering angle target value δ7. The lateral motion variable vy, necessary to derive δ, is found from α and −. This Vya is generally the above-mentioned vy, except for some special layers.
yo and vy have different values.

Then, the front wheel steering angle target value δ and the rear wheel steering angle target value δ obtained by the above equations (E) and (B) are outputted by the process A of step 48, and the front wheel steering device 4 and the rear wheel steering Device 5
is the front wheel 9, given the given steering angle target value δa or δ.
10 or the rear wheels 11, 12 is supplied to the hydraulic steering devices 6, 7, thereby steering the front wheels 9, 10 and the rear wheels 11, 12.

Through the above control operations, the yawing motion of the own vehicle is controlled by the first
The yaw motion characteristic at the target vehicle is equal to the yaw motion characteristic, and the lateral motion of the host vehicle is equal to the lateral motion characteristic at the second target vehicle.

Further, the yawing motion and lateral motion of the own vehicle controlled in this manner have independent characteristics that are not related to each other, and can be freely controlled without being restricted by each other.

Therefore, for example, when a sudden steering is performed as shown in FIG. The response is better than the characteristics shown in the figure (already shown).

Here, in a vehicle in which only one target vehicle is set in the prior application and a device for controlling the steering angle is installed, the tube rate change will be as shown in characteristic a as in the vehicle equipped with the device of this embodiment. However, looking at the lateral acceleration, as shown in Figure 7, the change characteristics of the lateral acceleration in the vehicle equipped with the device of the prior application are as shown by characteristic d in the figure. , compared to the characteristics of the conventional vehicle (indicated by characteristic e in the figure), it is non-vibratory, but compared to the characteristic of the vehicle equipped with the device of this embodiment (indicated by characteristic C in the figure), the occurrence is somewhat slow. It is.

This is because if the device of the prior application performs control with emphasis on the yaw rate, the lateral acceleration, which has a correlation with the yaw rate, will be affected and change.

On the other hand, the device of this embodiment can perform control that emphasizes the me-rate and control that emphasizes lateral acceleration independently of each other, so the yaw rate responsiveness and the Both the steep generation of lateral acceleration as shown in FIG. 7 can be realized.

Furthermore, by selecting a second target vehicle having characteristics related to lateral motion, it is also possible to make the sideslip angle zero, as shown in characteristic f shown in FIG. This kind of control is applicable not only to conventional vehicles (as shown by the characteristics in the figure), but also to vehicles equipped with the device of the prior application that emphasizes yaw rate responsiveness (
This control is also impossible for the characteristic g shown in the figure).

In addition, in the above embodiment, the front wheels 9, 10 and the rear wheels 11,
An example in which the present invention is applied to a four-wheel steering vehicle in which both front wheels 9 and 12 are steered using a hydraulic steering device 6°7 has been shown. It is also possible to apply the present invention to vehicles that are steered using a link type steering device.

In this case, as shown in FIG. 9, the rear wheels 11 and 12 are steered using the hydraulic steering system fi7, similar to the above embodiment, and the front wheels 9 and 10 are steered using a mechanical link steering system. The device 14 allows the steering handle 8
In addition, an auxiliary steering device 18 is provided to correct the front wheel steering angle so that it matches the front wheel steering angle target value aF for controlling the motion characteristics. is possible.

The correction amount Δδa of the front wheel steering angle at this time is determined by the following calculation such as the calculation of equation (16) and equation (to) among the calculations executed in step 47 in FIG. 4 in the above embodiment. ) and Ql) in the arithmetic expression.

βami=OF8/exa, ・
・・・・・・・・・・・・■Here, eKIP, : Own vehicle's front equivalent cornering power N8: Own vehicle's steering gear ratio, 8KF8 is when steering 1 stiffness is Ks1 trail is ξ , is expressed as .

If this is done, it will be equivalent to performing the same operation as in the above embodiment, and the same effect will be obtained.

(Effects of the Invention) As described above in detail, the present invention divides the target maneuverability into yawing motion and lateral motion, separately sets target vehicle models for each, and sets the target vehicle model for each separately. By controlling the steering angle of the vehicle's wheels so that the vehicle achieves the target values for yawing motion and lateral motion determined by calculation, the meowing motion characteristics and lateral motion characteristics can be improved. It becomes possible to properly control both independently.

Therefore, the range of motion performance control is widened and can be set freely, making it possible to control the sideslip angle to always be zero.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of the present invention, Fig. 2 is a block diagram of an embodiment of the present invention, and Fig. 8 is a block diagram of the front wheel steering device, rear wheel steering device, and hydraulic steering device in Fig. 2. , FIG. 4 is a flowchart showing the processing executed by the micro combinator in FIG. 2, and FIGS. 5 to 8 show the dynamic characteristics of the vehicle equipped with the embodiment shown in FIG. A characteristic diagram shown in comparison with a vehicle equipped with the device. FIG. 9 is a configuration diagram of another embodiment of the present invention. 100...Handle steering angle detection means 101...Vehicle speed detection means 102...Yawing motion target value calculation means 108...
- Lateral motion target value calculating means 104... Steering angle target value calculating means 105... Wheel steering means 1... Microcomputer 2... Handle steering amount sensor 8... Vehicle speed sensor 4... Front wheel steering device 6... Rear wheel steering device 6, F... Hydraulic steering device 8... Steering handle 9.10... Front wheels 11, 12... Rear wheel remainder... Yaw rate target value V... Yaw angle acceleration target value d... Lateral acceleration target value δ A... Front wheel steering angle target value δ8... Rear wheel steering angle target value Patent applicant Nissan Motor Co., Ltd. Figure 3 Figure 4 Figure 5 L ( Figure 6

Claims (1)

[Scope of Claims] 1. A steering wheel angle detection means for detecting a steering angle of a steering wheel; a vehicle speed detection means for detecting a vehicle speed; and a calculation regarding a first target vehicle model having a preset desired motion performance. yawing movement target value calculation means for calculating a target value of yawing movement corresponding to the steering angle of the steering wheel and the vehicle speed; a lateral motion target value calculation means for calculating a lateral motion target value corresponding to the steering angle of the steering wheel and the vehicle speed; and from the determined yawing motion target value, the lateral motion target value, and the vehicle specifications of the host vehicle; steering angle target value calculating means for calculating each target value of the steering angle of the front wheels and the rear wheels; and wheel steering means for steering each corresponding wheel of the front wheels and the rear wheels to the determined respective wheel steering angle target values. A steering angle control device for a vehicle, comprising: