JP2947040B2 - Auxiliary steering angle control device for vehicles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicular auxiliary steering angle control device for providing an auxiliary steering angle by feed forward control + yaw rate feedback control or the like.

[0002]

2. Description of the Related Art Conventionally, as an auxiliary steering angle control device for a vehicle for giving an auxiliary steering angle to rear wheels by feedforward control and yaw rate feedback control, for example, Japanese Patent Application Laid-Open No.
An apparatus described in Japanese Patent No. 18168 is known.

This conventional source has a reference model that is a desired yaw rate response model, determines a yaw rate target value using a vehicle speed, a steering angle, and a reference model, and obtains the yaw rate target value by interposing a delay element. A technique has been disclosed in which a value obtained as a yaw rate estimated value used in a yaw rate feedback system allows the feedback system to operate only when mainly absorbing disturbances and parameter fluctuations.

[0004]

However, in the above-described conventional auxiliary steering angle control device for a vehicle, the dynamic characteristics of the actuator steered by the feedforward component and the dynamic characteristics of the yaw rate sensor are not taken into account. Due to these dynamic characteristics, a deviation occurs between the yaw rate estimated value and the yaw rate detected value by the yaw rate sensor, and the yaw rate feedback system is activated.
There remains a problem that high-accuracy yaw rate feedback control cannot be performed.

That is, the gain of the electric actuator
Looking at the frequency response characteristic of the phase, as shown in FIG. 6, the characteristic decreases as the frequency increases, and as shown in FIG. 12, the frequency response characteristic of the gain / phase of the yaw rate sensor decreases as the frequency increases. It shows a decreasing characteristic. Therefore, the more suddenly the auxiliary steering angle is given, and the more rapidly the yaw rate changes occurring in the vehicle,
These dynamic characteristics cause errors in the yaw rate estimation value.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and a first object of the present invention is to provide an auxiliary steering angle control for a vehicle which provides an auxiliary steering angle by feedforward control + yaw rate feedback control or the like. It is an object of the present invention to achieve highly accurate feedback control that is not affected by the dynamic characteristics of an auxiliary steering angle actuator.

A second object is to achieve highly accurate feedback control which is not affected by the dynamic characteristics of the auxiliary steering angle actuator and the dynamic characteristics of the motion state amount detecting means.

[0008]

According to the first aspect of the present invention, a vehicle speed detecting means a and a steering angle detecting means are provided as shown in FIG. Means b, an auxiliary steering angle feedforward target value calculating means c for calculating an auxiliary steering angle feedforward target value based on the vehicle speed detection value and the steering steering angle detection value,
Exercise state quantity estimating means d for estimating the exercise state quantity generated in the own vehicle, exercise state quantity detection means e for detecting the same kind of exercise state quantity as the estimated exercise state quantity, exercise state quantity detection value and exercise state quantity An auxiliary steering angle feedback target value calculating means f for calculating an auxiliary steering angle feedback target value by compensation based on a deviation from the estimated value; and an auxiliary steering angle based on the sum of the auxiliary steering angle feedforward target value and the auxiliary steering angle feedback target value. An auxiliary steering angle for a vehicle comprising an auxiliary steering angle target value calculating means g for calculating a target value and an auxiliary steering angle control means i for outputting a control command for obtaining the auxiliary steering angle target value to an auxiliary steering angle actuator h. In the control device, the motion state amount estimating means d
Is actually calculated by the auxiliary steering angle feedforward target value using the actuator dynamic characteristic.
An actuator model d1 for estimating the amount by which
It is characterized by having a vehicle model d2 for estimating a motion state quantity using the auxiliary steering angle estimated value, the detected vehicle speed value, the detected steering angle value, and the linear two-degree-of-freedom plane vehicle model.

In order to achieve the second object, in the second invention according to the second aspect, as shown in the claim correspondence diagram of FIG. 1, in the vehicle auxiliary steering angle control device according to the first aspect,
The motion state quantity estimating means d includes an actuator model d
1 and a vehicle model d2, and a motion state quantity detection means model d3 for correcting a motion state quantity estimated value output from the vehicle model d2 using dynamic characteristics of the motion state quantity detection means e is provided. And

[0010]

The operation of the first invention will be described.

When the vehicle is running, the auxiliary steering angle feed forward target value calculating means c calculates the auxiliary steering angle feed forward based on the detected vehicle speed from the vehicle speed detecting means a and the detected steering angle from the steering angle detecting means b. A target value is calculated.

On the other hand, the motion state quantity estimating means d estimates the motion state quantity generated in the own vehicle, and the motion state quantity detecting means e detects the same motion state quantity as the estimated motion state quantity, and Angle feedback target value calculating means f
In, the auxiliary steering angle feedback target value is calculated by compensation based on the deviation between the motion state amount detection value and the motion state amount estimation value.

The auxiliary steering angle target value calculating means g calculates an auxiliary steering angle target value based on the sum of the auxiliary steering angle feedforward target value and the auxiliary steering angle feedback target value. A control command for obtaining the auxiliary steering angle target value is output to the auxiliary steering angle actuator h.

In estimating the motion state amount generated in the own vehicle by the motion state amount estimating means d, in the actuator model d1, the auxiliary steering angle actuator h is actually calculated by the auxiliary steering angle feedforward target value using the actuator dynamic characteristic. Is estimated and the vehicle model d
In 2, the motion state amount is estimated using the estimated auxiliary steering angle, the detected vehicle speed, the detected steering angle, and the linear two-degree-of-freedom plane vehicle model.

Therefore, since the motion state quantity is estimated by using the actuator model d1 in addition to the vehicle model d2, highly accurate feedback control not affected by the dynamic characteristics of the auxiliary steering angle actuator h is achieved. You.

The operation of the second invention will be described.

In estimating the motion state amount generated in the own vehicle by the motion state amount estimating means d, in the actuator model d1, the auxiliary steering angle actuator h is actually determined by the auxiliary steering angle feedforward target value using the actuator dynamic characteristic. The amount of operation is estimated, and in the vehicle model d2, the motion state amount is estimated using the auxiliary steering angle estimated value, the vehicle speed detected value, the steering steering angle detected value, and the linear two-degree-of-freedom plane vehicle model. In the means model d3, the estimated motion state value output from the vehicle model d2 is corrected using the dynamic characteristics of the motion state amount detection means e.

Therefore, by estimating the motion state quantity using the actuator model d1 and the motion state quantity detection means model d3 in addition to the vehicle model d2, the dynamic characteristic and the motion state quantity of the auxiliary steering angle actuator h are detected. A highly accurate feedback control not affected by the dynamic characteristics of the means e is achieved.

[0019]

Embodiments of the present invention will be described below with reference to the drawings.

The configuration will be described.

FIG. 2 is an overall system diagram showing a four-wheel steering vehicle to which the vehicle auxiliary steering angle control device according to the embodiment of the present invention is applied.

In FIG. 2, the front wheels 1 and 2 are steered by a steering handle 3 and a mechanical link type steering mechanism 4.
Done by This includes, for example, a steering gear, a pitman arm, a relay rod, side rods 5, 6, knuckle arms 7, 8, and the like.

The steering of the rear wheels 9, 10 is performed by an electric steering device 11 (corresponding to an auxiliary steering angle actuator h). The rear wheels 9, 10 are connected by a rack shaft 12, side rods 13, 14, and knuckle arms 15, 16, and a rack tube 17 in which the rack 12 is inserted has a speed reduction mechanism 18 and a motor 19.
The motor 19 and the fail-safe solenoid 20 are provided with a vehicle speed sensor 21 (corresponding to a vehicle speed detecting means a) and a front wheel steering angle sensor 22.
(Corresponding to the steering angle detecting means b), the rear steering angle sub-sensor 23, the rear steering angle main sensor 24, the yaw rate sensor 25 (corresponding to the motion state amount detecting means e) and the like. You.

FIG. 3 is a sectional view showing a specific structure of the electric steering apparatus 11.

In FIG. 3, the rack tube 17 in which the rack 12 is inserted is fixed to the vehicle body via a bracket. Side rods 13 and 14 are connected to both ends of the rack 12 via ball joints 30 and 31. The reduction mechanism 18 includes a motor pinion 32 connected to the motor shaft of the motor 19, a ring gear 33 meshing with the motor pinion 32, and a rack pinion 35 fixed to the ring gear 33 and meshing with the rack gear 12a. Have been. Therefore, when the motor shaft of the motor 19 rotates, the rotation is transmitted to the motor pinion 32 → the ring gear 33 → the rack pinion 35, and the rack shaft 12 moves in the axial direction due to the engagement between the rotating rack pinion 35 and the rack gear 12a. The rear wheels 9, 10 are steered. This rear wheel 9,10
Is proportional to the amount of movement of the rack shaft 12, that is, the amount of rotation of the motor shaft.

The rack pinion 35 is provided with a rear steering angle main sensor 24 having a potentiometer structure for detecting the rear wheel steering angle based on the rotation amount.

The fail-safe solenoid 20 includes:
The lock pin 20a is provided so as to be able to advance and retreat, and when the electronic control system or the like fails, the lock shaft 20a is fitted into a lock groove 12b formed in the rack shaft 12 so that the rack shaft 12 and the rear wheels 9, 10 can be moved. It is fixed at a position to maintain the neutral steering angle position.

The operation will be described.

[Rear Wheel Steering Angle Control Operation] FIG. 4 is a flowchart showing the flow of the rear wheel steering angle control operation performed by the controller 26. Each step will be described below.

In step 40, the vehicle speed V, the steering angle θ, the actual yaw rate ψ's, and the rear steering angle main sensor value δ
rs is read.

Here, the actual yaw rate ψ's is calculated based on the yaw rate sensor value Vψ 'from the yaw rate sensor 25 and the latest yaw rate zero correction memory value V obtained by the detected yaw rate correction processing for removing the influence of the temperature drift.
Calculated by ψ'om.

In step 41, the rear wheel steering angle feedforward target value δRFF is calculated by the following equation based on the phase inversion delay control method using the vehicle speed V and the steering angle θ.
^* (Hereinafter, * indicates a target value) is calculated (corresponding to the auxiliary steering angle feedforward target value calculating means c).

ΔRFF ^* = Kθ + τθ + τ′θ In step 42, when the rear wheel steering angle feedforward target value δRFF ^* is given using the actuator model, the rear wheel steering angle actuator is the amount by which the rear wheel actually steers the rear wheels. A wheel steering angle estimated value δRFF ^# (hereinafter, # represents an estimated value) is calculated (corresponding to the actuator model d1). As will be described in detail later, the actuator model is
It is given by the transmission characteristic of the actual rear wheel steering angle obtained by driving the actual actuator with respect to the rear wheel steering angle command value.

In step 43, a vehicle model is used to calculate an estimated yaw rate ψ '^# when the vehicle is assumed to run with the vehicle speed V, the steering angle θ and the estimated rear wheel steering angle δRFF ^#. Corresponding to model d2). Although described in detail later, a linear two-degree-of-freedom plane vehicle model is used as the vehicle model.

In step 44, an estimated yaw rate ψ's ^# is calculated from the estimated yaw rate ψ '^# using the yaw rate sensor model (corresponding to the motion state amount detecting means model d3). As will be described in detail later, the yaw rate sensor model is given by a transfer function based on an experimental result of a sensor dynamic characteristic such as a frequency response of the sensor.

Steps 42 to 44 correspond to the motion state amount estimating means d.

In step 45, the yaw rate deviation ψ'e is calculated from the difference between the actual yaw rate ψ's and the estimated yaw rate ψ's ^# .

In step 46, the high-frequency noise included in the output of the yaw rate sensor 25 is removed by the feedback compensator-1 constituting a first-order lag filter.

The input signal of the feedback compensator-1 is ψ'e, and the output signal is ψ'ec1.

In step 47, the transient response of the vehicle to the disturbance is adjusted by the feedback compensator-2 constituting a first-order / first-order filter.

The input signal of the feedback compensator-2 is ψ'ec1 and the vehicle speed V, and the output signal is ψ'ec2.

In step 48, the feedback rear wheel steering angle command value δRFBO ^{* is} obtained by the feedback proportional gain Kp ^.
Is calculated.

The input signal of the proportional gain is ψ'ec2 and the vehicle speed V, and the output signal is δRFBO ^* .

[0044] At step 49, depending on the vehicle speed V, the following feedback was smoothly limits the maximum value of the feedback rear wheel steering angle command value DerutaRFBO ^* wheel steering angle limit command value DerutaRFBL ^* is calculated.

The input signals of the steering angle limiter are δRFBO ^* and the vehicle speed V, and the output signal is δRFBL ^* .

[0046] At step 50, a hysteresis is provided in a feedback rear wheel steering angle limit command value DerutaRFBL ^*, feedback rear wheel steering angle limit command value to remove the vibration of minute yaw rate by feedback DerutaRFBH ^* is calculated.

The input signal of this small change absorber is δRFBL ^*
And the rear wheel steering angle feedback target value ΔRFB ^* , and the output signal is ΔRFBH ^* .

In step 51, the transfer characteristic set in the actuator control system is changed to a desired transfer characteristic by the actuator phase compensator constituting the secondary / secondary filter, and the rear wheel steering angle feedback target value δRFB ^* Is calculated.

The input signal of this actuator phase compensator is δRFBH ^* , and the output signal is δRFB ^* .

Steps 45 to 51 correspond to the auxiliary steering angle feedback target value calculating means f.

In step 52, the rear wheel steering angle feed forward target value δRFF ^* and the rear wheel steering angle feedback target value δ
The rear wheel steering angle target value δR ^* is calculated from the sum of RFB ^* and RFB ^* (corresponding to auxiliary steering angle target value calculating means g).

In step 53, a command (motor control current by PWM) for obtaining the rear wheel steering angle target value δR ^* is output using the rear steering angle main sensor value δrs and the robust model matching method (auxiliary steering angle control). Means i).

[Estimated Yaw Rate Calculation Processing] FIG. 5 is a block diagram showing a yaw rate estimated value calculation unit. The yaw rate estimated value calculation unit is composed of an actuator model 60, a vehicle model 61, and a yaw rate sensor model 62. Hereinafter, each model will be described.

* Actuator Model The actuator model receives the rear wheel steering angle feedforward target value δRFF ^* and estimates the amount by which the electric steering device 11, which is the rear wheel steering angle actuator, actually steers the rear wheels 9, 10. I do.

The solid line characteristics in FIG. 6 indicate the electric steering device 11 driven by the robust model matching control.
Is a frequency characteristic of the actual rear wheel steering angle δR with respect to the rear wheel steering angle command value δR ^# , and the following transfer function G approximated to this characteristic:
ACT (S) is used as the actuator model.

GACT (S) = δR / δR ^# = (ω ² nACT) /
(S ² + 2ζACT · ωnACT + ω ² nACT) Accordingly, when the rear wheel steering angle feedforward target value δRFF ^* is given to the above transfer function as the rear wheel steering angle command value δR ^# , the dynamic characteristics of the electric steering device 11 The rear wheel steering angle estimated value ΔRFF ^{# from} which the influence is removed can be calculated.

* Vehicle Model The vehicle model receives the vehicle speed V, the steering angle θ, and the estimated rear wheel steering angle δRFF ^# , and calculates the estimated yaw rate ψ ′ ^# .

As shown in FIG. 7, this vehicle model includes a high-lateral G nonlinear map 61a, a linear two-degree-of-freedom plane vehicle model 61b, a steering neutral vicinity gain adjuster 61c, a vehicle speed yaw rate gain adjuster 61d. It comprises a dead time adjuster 61e. Then, basically, the yaw rate estimation value ψ '^# is calculated using the linear two-degree-of-freedom plane vehicle model 61b, but the influence of high-frequency dynamics such as the dynamic characteristics of the steering mechanism and tires is approximated by dead time. In addition, adjustment is performed by various steady-state characteristic adjusters 61a, 61c, and 61d so as to remove the influence of the nonlinear characteristic of the actual vehicle.

(High-lateral G nonlinear map 61a) The yaw rate estimation value output from the linear two-degree-of-freedom plane vehicle model has a medium-low steering response even in a high-lateral G region where the cornering force of the tire is saturated. It is not different from the horizontal G area. Therefore, in the high lateral G region, a deviation occurs between the yaw rate of the actual vehicle and the yaw rate of the vehicle model, and the rear wheel steering angle feed forward target value δRFF ^* is greatly corrected by the rear wheel steering angle feedback target value δRFB ^* .
The driver may feel uncomfortable.

Therefore, an estimated steady-state linear lateral acceleration Go is calculated from the vehicle speed V and the steering angle θ, and the steering angle θ and the estimated rear wheel steering angle δRFF ^# are limited based on the estimated lateral acceleration Go. The yaw rate nonlinearity in the high lateral G region can be represented by a vehicle model. Less than,
The restriction method will be described.

[0061] ^{Go = {V 2 / (1} + AM · V 2) · LM}
{(Θ / NM) -Kθ} However, K [theta; a rear wheel steering angle feedforward target value DerutaRFF ^* calculation coefficient (proportional term); a rear wheel steering angle feedforward target value DerutaRFF ^* constant values K.

[0062] The calculated steady lateral G estimated correction value G ₁ corresponding to Go from one variable map shown in FIG. 8, calculates the steering angle limit value θLIM by the following equation.

Θ LIM = {G ₁ · (1 + AM · V ² ) LM} /
{(1 / NM−K) V ² } Next, the rear wheel steering angle estimation limit value δRFFL ^# is calculated by δRFFL ^# = (θLIM / θ) δRFF ^# .

The one-variable map shown in FIG. 8 includes two regions, a linear region and a non-linear region. The linear region is represented by Go = G ₁
And does not impose any restrictions. In the nonlinear region, G corresponding to Go
₁ is G ₁ = G ₁₁ + (G ₁₂ −G ₁₁ ) {1-exp [− (Go −
G ₁₁ ) / (G ₁₂ −G ₁₁ )]｝, and are calculated so as to be smoothly connected by a logarithmic function curve, and the steering angle and the estimated value of the rear wheel steering angle are limited.

(Linear two-degree-of-freedom plane vehicle model 61b) The linear two-degree-of-freedom plane vehicle model 61b is composed of the yawing motion of the vehicle and the lateral direction, and can be linearized and expressed by the following equation.

IZMψ '^# = 2LFMFMCFM-2LRM ・ CRM MM ・ V'yM ^# =-MM ・ Vψψ'^# + 2CFM + 2CRM where CFM = eKFM ｛θLIM / NM- (VyM ^# + LFMψ '^# ) /
V｝ CRM = KRM ｛δRFFL ^# − (VyM ^# · θLIM −LRMψ '^# ) /
V｝ IZM: Yaw moment of inertia LFM: Distance between center of gravity and front axle LRM: Distance between center of gravity and rear axle CFM: Front wheel cornering force CRM: Rear wheel cornering force MM: Vehicle model mass V'yM ^# : Lateral acceleration V : Lateral speed ψ '^# : Estimated yaw rate eKFM: Front-wheel equivalent cornering power KRM: Rear-wheel equivalent cornering power (gain adjuster near steering neutral 61c)
In the vicinity of steering neutral (± 10 ° or less), the yaw rate gain differs from the middle steering area frequently used in ordinary running due to the influence of wheel alignment and the like. If the vehicle model does not adjust the yaw rate gain in the vicinity of the steering neutral, a yaw rate deviation occurs at the start of steering turning or the like, and the following problem may occur.

1) The vehicle becomes sensitive due to road surface disturbance and the like, and the straightness is deteriorated.

2) The response of yaw and lateral G to steering deteriorates.

3) The balance of yaw and lateral G and the roll mode are broken.

Therefore, a one-variable map shown in FIG. 9 is created so that the yaw rate gain Kψ'S corresponding to the steering angle can be set.

Therefore, the output of the adjuster 61c is calculated from the estimated yaw rate value ψ '^# from the vehicle model 61b and the yaw rate gain Kψ'S by the following equation.

Ψ'STR ^# = Kψ'S × ψ '^# (vehicle speed yaw rate gain adjuster 61d) The yaw rate gain of the vehicle model can be adjusted by the vehicle speed for the following reason.

1) Correspondence to Stability Factor Change In a vehicle model, the stability factor is constant irrespective of the vehicle speed. However, in an actual vehicle, the stability factor generally changes slightly depending on the vehicle speed.

2) Correspondence for executing digital operation of a stable vehicle model At a vehicle speed of 20 km / h or less, the natural frequency of the vehicle is very high, and the simple two-degree-of-freedom vehicle model is obtained by simple Euler integration with a sampling time of 5 ms. May diverge instead of converging. Therefore, at a vehicle speed of 20 km / h or less, the vehicle speed input to the linear two-degree-of-freedom vehicle model is 20 km
/ h, so that the yaw rate gain Kψ'V is corrected according to the vehicle speed.

Although the above 1) and 2) are completely different requirements, FIG.
The map shown in FIG.

(Dead Time Adjuster 61e) The response of the yaw rate to the steering angle is delayed in the actual vehicle due to the influence of high-frequency dynamics that cannot be considered in the linear two-degree-of-freedom plane vehicle model. In the vehicle model, the delay of the yaw rate is approximately expressed by a dead time.

As shown in the yaw rate-steering angle frequency response comparison result of FIG. 11, the “linear two-degree-of-freedom plane vehicle model +
The calculated value based on the "dead time" and the experimental value agree very well in both the gain and the phase, and it is understood that it is appropriate to approximate the delay of the yaw rate by the dead time.

[0078] * yaw rate sensor model yaw rate sensor model, in which dynamic characteristics of the yaw rate sensor 25 is set when a not negligible with respect to the dynamic characteristics of the vehicle, enter the yaw rate estimated value [psi ^'#, estimated Calculate yaw rate ψ's ^# .

The solid line characteristics in FIG. 12 are the results of a frequency response experiment of the yaw rate sensor 25 used in this control system, and the following transfer function GSEN (S) of the first-order lag identified by curve fitting is used as the yaw rate sensor model. And

GSEN (S) = ψ ′s ^# (S) / ψ ′ ^# (S) = 1 / (TSEN · S + 1) Therefore, when the yaw rate estimated value ψ ′ ^# is given to the above transfer function equation, the yaw rate sensor 25 Estimated yaw rate ψ's ^# excluding the influence of the dynamic characteristic of can be calculated.

[Rear Wheel Steering Angle Control Action] The rear wheel steering angle control action during traveling is executed according to the flowchart shown in FIG.

That is, in step 41, the vehicle speed V
The rear wheel steering angle feedforward target value ΔRFF ^* is calculated by an equation based on a phase inversion delay control method using the steering angle θ and the steering angle θ.

On the other hand, in steps 42 to 44, the estimated yaw rate に 's ^#
In steps 45 to 51, rear wheel steering angle feedback is performed by compensation based on a yaw rate deviation ψ'e which is a difference between the actual yaw rate ψ's based on the yaw rate sensor value V 値 'from the yaw rate sensor 25 and the estimated yaw rate ψ's ^#. The target value ΔRFB ^* is calculated.

Then, in step 52, the rear wheel steering angle target value δR ^* is calculated by the sum of the rear wheel steering angle feedforward target value δRFF ^* and the rear wheel steering angle feedback target value δRFB ^*. A control command for obtaining the wheel steering angle target value δR ^* is output to the motor 19 of the electric steering device 11.

In estimating the estimated yaw rate ψ's ^# generated in the own vehicle in steps 42 to 44,
In the actuator model 60 in step 42, the estimated rear wheel steering angle δRFF ^# is calculated by removing the influence of the dynamic characteristics of the electric steering device 11 from the rear wheel steering angle feedforward target value δRFF ^*, and the vehicle model 6 in step 43 is calculated.
In step 1, the estimated yaw rate ψ ′ ^# is calculated using the rear wheel steering angle estimated value δRFF ^# , the vehicle speed V, the steering angle θ, and the linear two-degree-of-freedom plane vehicle model. Yaw rate sensor 2
The estimated yaw rate ψ ′s ^{# obtained} by correcting the yaw rate estimated value ψ ′ ^# output from step 43 using the dynamic characteristic of ^{No. 5} is calculated.

Therefore, by calculating the estimated yaw rate ψ's ^# using the actuator model 60 and the yaw rate sensor model 62 in addition to the vehicle model 61, the dynamic characteristics of the rear wheel steering device 11 and the dynamic characteristics of the yaw rate sensor 25 are calculated. A highly accurate feedback control not affected by the above is achieved. In other words, since the estimated yaw rate ψ's ^# is accurately calculated, the feedback control does not work during normal driving unless it is affected by disturbance.

The effect will be described.

(1) In a vehicular auxiliary steering angle control device that provides a rear wheel steering angle by feedforward control and yaw rate feedback control, when estimating an estimated yaw rate 推定 's ^# generated in the own vehicle, a rear wheel steering angle feedforward target value is used. An actuator model 60 for calculating an estimated rear wheel steering angle δRFF ^# by removing the influence of the dynamic characteristics of the electric steering device 11 from δRFF ^*, and an estimated rear wheel steering angle δ
Since the system is performed using the RFF ^# , the vehicle speed V, the steering rudder angle θ, and the vehicle model 61 for calculating the yaw rate estimated value ψ ′ ^# using the linear two-degree-of-freedom plane vehicle model, the dynamic characteristics of the electric steering device 11 A highly accurate feedback control not affected by the above can be achieved.

(2) Estimated yaw rate に 's ^# generated in own vehicle
In estimating the, applied to the actuator model 60 and the vehicle model 61, as an apparatus for performing with a yaw rate sensor model 62 to calculate the estimated yaw rate [psi's ^# obtained by correcting the yaw rate estimated value [psi ^'# using the dynamic characteristic of the yaw rate sensor 25 The electric steering device 1
1 and high-accuracy feedback control that is not affected by the dynamic characteristics of the yaw rate sensor 25 can be achieved.

(3) Since the vehicle model 61 is provided with a dead time adjuster 61f in addition to the linear two-degree-of-freedom plane vehicle model 61b, the influence of high-frequency dynamics such as the dynamic characteristics of the steering mechanism and tires is reduced. Can be removed.

(4) The vehicle model 61 includes various linear characteristic adjusters 61 in addition to the linear two-degree-of-freedom plane vehicle model 61b.
Since the apparatus is provided with a, 61c, and 61d, it is possible to remove the influence of the non-linear characteristics of the actual vehicle near the steering neural or in the high lateral G region.

Although the embodiments have been described with reference to the drawings, the specific configuration is not limited to the embodiments, and any changes or additions without departing from the gist of the present invention are included in the present invention. It is.

For example, in the embodiment, the example of the auxiliary steering angle control device for giving the auxiliary steering angle only to the rear wheel has been described, but the auxiliary steering angle control device for giving the auxiliary steering angle only to the front wheel or the front and rear wheels may be used. Can be applied.

In the embodiment, the example in which the yaw rate is used as the motion state amount has been described. However, the lateral speed, the lateral acceleration, or the yaw momentum expressing these in a complex manner may be used.

In the embodiment, the example in which the electric steering device is used as the auxiliary steering angle actuator has been described. However, the present invention can be applied to a hydraulic or pneumatic steering device.

[0096]

According to the first aspect of the present invention,
In a vehicular auxiliary steering angle control device for providing an auxiliary steering angle by feed forward control + yaw rate feedback control, etc., a motion state amount estimating means is realized by actually using an auxiliary steering angle feed forward target value using an actuator dynamic characteristic to obtain an auxiliary steering angle actuator. Means having an actuator model for estimating the amount of operation of the vehicle, and a vehicle model for estimating the motion state amount using the auxiliary steering angle estimated value, the vehicle speed detected value, the steering steering angle detected value, and the linear two-degree-of-freedom plane vehicle model. As a result, it is possible to achieve an effect that highly accurate feedback control that is not affected by the dynamic characteristics of the auxiliary steering angle actuator can be achieved.

According to a second aspect of the present invention, in the vehicle auxiliary steering angle control device according to the first aspect, the motion state amount estimating means is added to the actuator model and the vehicle model, and the motion state amount is detected. The dynamic state of the auxiliary steering angle actuator and the dynamic state of the dynamic state amount detecting means are provided because the dynamic state amount detecting means model for correcting the moving state amount estimated value output from the vehicle model using the dynamic characteristics of the means is provided. The effect is obtained that highly accurate feedback control not affected by the dynamic characteristics can be achieved.

[Brief description of the drawings]

FIG. 1 is a diagram corresponding to a claim showing an auxiliary steering angle control device for a vehicle according to the present invention.

FIG. 2 is an overall system diagram showing a four-wheel steering vehicle to which the vehicle auxiliary steering angle control device of the embodiment is applied.

FIG. 3 is a cross-sectional view of the electric steering device of the embodiment device.

FIG. 4 is a flowchart illustrating a flow of a rear wheel steering angle control operation performed by a controller of the embodiment device.

FIG. 5 is a block diagram illustrating a yaw rate estimated value calculation unit of the embodiment device.

FIG. 6 is a frequency characteristic diagram of an electric steering device used in setting an actuator model.

FIG. 7 is a block diagram showing a detailed configuration of a vehicle model.

FIG. 8 is a high-lateral G nonlinear map.

FIG. 9 is a diagram showing a yaw rate gain map with respect to a steering angle.

FIG. 10 is a diagram showing a yaw rate gain map with respect to a vehicle speed.

FIG. 11 is a diagram showing a yaw rate-steering angle frequency response comparison result.

FIG. 12 is a diagram showing a frequency response experiment result of the yaw rate sensor.

[Explanation of symbols]

 a vehicle speed detecting means b steering rudder angle detecting means c auxiliary steering angle feedforward target value calculating means d motion state quantity estimating means d1 actuator model d2 vehicle model d3 motion state quantity detecting means model e motion state quantity detecting means f auxiliary steering angle feedback Target value calculation means g Auxiliary steering angle target value calculation means h Auxiliary steering angle actuator i Auxiliary steering angle control means

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-3-7666 (JP, A) JP-A-5-229443 (JP, A) JP-A-2-18168 (JP, A) JP-A-5-208 185946 (JP, A) (58) Field surveyed (Int. Cl. ⁶ , DB name) B62D 6/00 B62D 7/14

Claims (2)

(57) [Claims] 1. A vehicle speed detecting means, a steering steering angle detecting means, an auxiliary steering angle feedforward target value calculating means for calculating an auxiliary steering angle feedforward target value based on a vehicle speed detected value and a steering steering angle detected value, Exercise state quantity estimation means for estimating the exercise state quantity generated in the own vehicle, exercise state quantity detection means for detecting the same exercise state quantity as the estimated exercise state quantity, exercise state quantity detection value and exercise state quantity estimation value An auxiliary steering angle feedback target value calculating means for calculating an auxiliary steering angle feedback target value by compensation based on a deviation from the target steering angle, and an auxiliary steering angle target value based on the sum of the auxiliary steering angle feedforward target value and the auxiliary steering angle feedback target value. An auxiliary steering angle target value calculating means for calculating, and an auxiliary steering angle control means for outputting a control command for obtaining the auxiliary steering angle target value to the auxiliary steering angle actuator. In the vehicle auxiliary steering angle control device, the motion state amount estimating means, an actuator model that estimates the actual amount of operation of the auxiliary steering angle actuator by the auxiliary steering angle feed forward target value using the actuator dynamic characteristics, An auxiliary steering angle control device for a vehicle, comprising: a vehicle model for estimating a motion state amount by using the estimated auxiliary steering angle value, the detected vehicle speed value, the detected steering angle value, and the linear two-degree-of-freedom plane vehicle model. . 2. The vehicle auxiliary steering angle control device according to claim 1, wherein the motion state quantity estimating means outputs from the vehicle model using dynamic characteristics of the motion state quantity detecting means in addition to the actuator model and the vehicle model. A vehicle auxiliary steering angle control device, comprising: a motion state quantity detection means model for correcting the estimated motion state quantity.