JP2936975B2 - 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 an auxiliary steering angle control device for a vehicle which drives an electric steering angle actuator by using an auxiliary steering angle feedback operation amount corresponding to a difference between a target value and a detection value of a motion state amount.

[0002]

2. Description of the Related Art Conventionally, as an auxiliary steering angle control device for a vehicle, for example, the one described in Japanese Patent Application Laid-Open No. Sho 62-247979 is known.

[0003] In the above-mentioned conventional publication, when an auxiliary steering angle is applied to at least one of the front and rear wheels, the auxiliary steering angle is applied by feedforward control based on an auxiliary steering angle operation amount for obtaining a target amount of motion, and at the same time, road surface disturbance and the like are provided. When the motion state amount of the vehicle is disturbed, the auxiliary steering angle feedback operation amount corresponding to the difference between the target value and the detection value of the movement state amount is provided so as to correct the amount of the unstable element, and the vehicle is stabilized. A technique for obtaining a desired motion state by control is shown.

[0004]

However, according to the above-mentioned conventional technology, even if the power supply capability is reduced and the power supply voltage is reduced from 14 V to 8 V, for example, the controller can control the vehicle according to the running state of the vehicle. In order to perform the same feedback control as in the case where the power supply has not deteriorated, for example, if an attempt is made to flow a current of 20 A, an actuator in which a voltage drop of 8 V or more occurs due to a power element or a back electromotive voltage, the power supply Is less than or equal to 8 V, a desired current (here, 20 A) cannot be flowed, and a response delay occurs in the actuator, giving the driver an uncomfortable feeling of vehicle behavior.

In addition, when the power supply voltage is lowered due to an excessive load, power cannot be supplied to another system using the same power supply, so that another system is adversely affected. Was.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problem, and an object thereof is to use an auxiliary steering angle feedback operation amount corresponding to a difference between a target value and a detection value of a motion state amount. In a vehicular auxiliary steering angle control device that drives an electric steering angle actuator, when a power supply voltage is reduced, it is possible to suppress a feeling of strangeness to a driver and to prevent an influence on other systems using the same power supply. .

[0007]

In order to achieve the above-mentioned object, a vehicle auxiliary steering angle control device according to the present invention comprises a vehicle state detecting means a for detecting a vehicle state, as shown in the claim correspondence diagram of FIG. A motion state quantity target value calculating means b for calculating a motion state quantity target value by using the vehicle state detection value as an input; an actual motion state quantity detecting means c for detecting a motion state quantity actually occurring in the vehicle; Auxiliary steering angle feedback operation amount determining means d for determining an auxiliary steering angle feedback operation amount according to a difference between the target amount of exercise state amount and the detected actual movement state amount value
And power supply voltage state detection means f for detecting a power supply voltage state of an electric steering angle actuator e for electrically providing an auxiliary steering angle.
And an auxiliary steering angle feedback operation amount correction unit g that monitors the power supply voltage and, when it is determined that the power supply capability of the power supply is insufficient, reduces the auxiliary steering angle feedback operation amount. It is characterized by having.

[0008]

When the power supply voltage detected by the power supply voltage state detection means f is monitored and the power supply capability to the electric steering angle actuator e is determined to be sufficient, the auxiliary steering angle feedback operation amount determination means d determines the motion. Based on the auxiliary steering angle feedback operation amount determined according to the difference between the movement amount target value calculated by the state amount target value calculation means b and the actual movement state amount detection value detected by the actual movement state amount detection means c. As a result, the electric steering angle actuator e is driven.

When it is determined by monitoring the power supply voltage detected by the power supply voltage state detection means f that the power supply capability to the electric steering angle actuator e is insufficient, the auxiliary steering angle feedback operation amount correction means g The electric steering angle actuator e is driven with a value obtained by reducing the auxiliary steering angle feedback operation amount determined by the auxiliary steering angle feedback operation amount determining means d.

Therefore, when the power supply voltage drops, which causes a response delay to the electric steering angle actuator e, the difference between the movement state target value and the actual movement state detection value increases, and this is the auxiliary steering angle feedback operation amount. When the electric steering angle actuator e is driven on the basis of the large auxiliary steering angle feedback operation amount, the vehicle behavior becomes vibrating and gives a sense of incongruity to the driver. When it is determined that the power supply capability to the actuator e is insufficient, a correction for reducing the auxiliary steering angle feedback operation amount is performed, so that the vehicle behavior is reduced, and a sense of discomfort to the driver is suppressed.

Further, when the auxiliary steering angle feedback operation amount is increased when the power supply voltage decreases, the reduction of the power supply voltage is further promoted. However, the correction for reducing the auxiliary steering angle feedback operation amount is performed. Adverse effects on other systems using the same power supply are minimized.

[0012]

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

First, the configuration will be described.

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

In FIG. 2, reference numerals 1 and 2 denote front wheels which are steered by a mechanical link type steering device 3 operated by a steering operation by a driver. Reference numerals 4 and 5 denote rear wheels which are steered by an electric steering angle actuator 6.

Reference numeral 7 denotes a controller, which is configured using a microcomputer or another electric circuit.

The controller 7 includes a steering angle θ from a steering angle sensor (corresponding to vehicle state detecting means a) 8 and a vehicle speed V from a vehicle speed sensor (corresponding to vehicle state detecting means a) 9.
x, a yaw rate dψ from a yaw rate sensor (corresponding to the actual motion state amount detecting means c) 10 and a detection signal of a power supply voltage VB from a voltage sensor (corresponding to the power supply voltage state detecting means f) 11 are inputted. Based on the input, predetermined arithmetic processing is executed to determine the steering angle operation amount δr for the rear wheels 4 and 5, and a drive command for obtaining the auxiliary steering angle operation amount δr is output to the electric steering angle actuator 6.

FIG. 3 shows a block diagram of each processing performed by the controller 7, and the yaw rate target value calculating section (corresponding to the exercise state target value calculating means b).
21, auxiliary steering angle feed forward manipulated variable calculator 22,
Auxiliary steering angle feedback operation amount calculation unit (corresponding to auxiliary steering angle feedback operation amount determination means d) 23, power supply voltage monitoring unit 24, auxiliary steering angle feedback operation amount correction unit (equivalent to auxiliary steering angle feedback operation amount correction means g) 27, an auxiliary steering angle operation amount calculation unit 28 is provided.

The yaw rate target value calculating section 21 receives signals of the steering angle θ detected by the steering angle sensor 8 and the vehicle speed Vx detected by the vehicle speed sensor 9, and based on these inputs, the motion state target value. Yaw rate target value d as
ψM is calculated.

The auxiliary steering angle feedforward manipulated variable calculator 22 calculates an auxiliary steering angle feedforward manipulated variable δrf for the feedforward that obtains the yaw rate target value dψM calculated by the yaw rate target value calculator 21.

The auxiliary steering angle feedback operation amount calculating section 23 receives the yaw rate target value dψM calculated by the yaw rate target value calculating section 21 and the generated yaw rate dψ detected by the yaw rate sensor 10, and calculates the difference e (| dψM−dψ |), and the auxiliary steering angle feedback operation amount δrB is calculated in accordance with the difference e.

In the power supply voltage monitoring section 24, a low pass filter (LPF) 25 changes the power supply voltage VB of the electric steering angle actuator 6 detected by the voltage sensor 11 to a smoothed power supply voltage VBL, and a command correction rate. By the calculation unit 26,
The command correction rate Rs for the smoothed power supply voltage VBL is calculated.

In the auxiliary steering angle feedback operation amount correction section 27, the auxiliary steering angle feedback operation amount calculation section 2
The auxiliary steering angle feedback operation amount δrB calculated in step 3 is corrected by the command correction rate Rs calculated by the power supply voltage monitoring unit 24 to obtain an auxiliary steering angle feedback operation amount correction value δrB.
M is calculated.

The auxiliary steering angle operation amount calculating section 28 corrects the auxiliary steering angle feed forward operation amount δrf calculated by the auxiliary steering angle feed forward operation amount calculating section 22 by the auxiliary steering angle feedback operation amount correcting section 27. The auxiliary steering angle operation amount δr (= δrf + δrBM) is calculated by adding the corrected auxiliary steering angle feedback operation amount correction value δrBM.

Next, the operation will be described.

[Calculation of auxiliary steering angle operation amount for F / F and F / B] Calculation of auxiliary steering angle feedforward operation amount δrf in auxiliary steering angle feedforward operation amount calculation unit 22 and auxiliary steering angle feedback operation amount The calculation of the auxiliary steering angle feedback manipulated variable correction value δrBM in the calculation unit 23 is described in
The calculation is performed by the method described in Japanese Patent No.

[Monitoring of Power Supply Voltage] As shown in FIG. 4A, the power supply voltage VB of the electric steering angle actuator 6 detected by the voltage sensor 11 changes with time t. The cause of this change is that power consumption during operation when duty control such as PWM (pulse modulation) is performed in the electric steering angle actuator 6 is large.

Since it is difficult to accurately measure the power supply voltage VB with such a voltage fluctuation, the power supply voltage VB is smoothed using the low-pass filter 25 as shown in FIG.
For example, as the low-pass filter 25, a filter such as the following equation (1) is used.

VBL / VB = 1 / (1 + τL · s) (1) where τL is a time constant and VBL is a smoothing power supply voltage.

[Method of Adjusting Feedback Operation Amount] The smoothed power supply voltage VBL is input to a command correction rate calculator 26, which uses the map shown in FIG. The value of the command correction rate Rs for VBL is obtained.

The auxiliary steering angle feedback operation amount correction value δrBM is calculated by the following equation (2) using the auxiliary steering angle feedback operation amount δrB in the auxiliary steering angle feedback operation amount calculation section 23 and the command correction rate Rs. You.

ΔrBM = δrB × Rs (2) Here, the map of FIG. 5 has a characteristic that the command correction rate Rs changes as follows depending on the value of the smoothed power supply voltage VBL.

Rs = 1 (VBL ≧ Va) (3) 0 <Rs <1 (Vb <VBL <Va) (4) Rs = 0 (VBL ≦ Vb) (5) where Va and Vb are predetermined. And, in particular, Va
Is determined as a limit value at which the electric steering angle actuator 6 can have a desired frequency response.

[Normal Power Supply Voltage] When the power supply voltage VBL is normal to a certain value or more, VBL ≧ Va, and Rs = 1 according to the above equation (3). Then, δrBM is obtained by the above equation (2).
= ΔrB.

As a result, the auxiliary steering angle feedback operation amount δrB in the auxiliary steering angle feedback operation amount calculation unit 23 is not corrected.

Therefore, when the vehicle is turning without cross-wind disturbance or the like, the rear wheels 4 and 4 are substantially controlled only by the feedforward control.
5 is controlled, and when the yaw motion of the vehicle is disturbed by a cross wind disturbance or the like, the auxiliary steering angle feedforward in the feedforward control is performed by the feedback control using the auxiliary steering angle feedback operation amount δrB. By modifying the manipulated variable δrf, the auxiliary steering angles to the rear wheels 4 and 5 are controlled, and the vehicle behavior is prevented from becoming unstable due to crosswind disturbance or the like.

[Power supply voltage drop] When the power supply voltage is lowered due to an excessive load or the like, when Vb <VBL <Va, 0 <Rs <1 is established by the above equation (4), and when VBL ≦ Vb, According to the above equation (5), Rs = 0.

When 0 <Rs <1, a correction is made to reduce the auxiliary steering angle feedback operation amount δrB by δrBM = δrB × Rs in the above equation (2). Also, R
When s = 0, the auxiliary steering angle feedback operation amount correction value δ
rBM is set to δrBM = 0, and the feedback control is prohibited.

As a result, when the power supply voltage drops causing a response delay to the electric steering angle actuator 6, the difference e between the yaw rate target value dψM and the generated yaw rate dψ increases,
This amount appears in the auxiliary steering angle feedback operation amount δrB,
When the electric steering angle actuator 6 is driven based on the large auxiliary steering angle feedback operation amount δrB, the yaw rate generated in the vehicle vibrates and gives a feeling of strangeness to the driver. When it is determined that the power supply capability to the angular actuator 6 is insufficient, the vehicle behavior is reduced by performing a correction to reduce the auxiliary steering angle feedback operation amount δrB,
The discomfort to the driver is suppressed.

If the auxiliary steering angle feedback operation amount δrB is increased when the power supply voltage is reduced, the reduction of the power supply voltage is further promoted. However, a correction for reducing the auxiliary steering angle feedback operation amount δrB is performed. Thus, adverse effects on other systems using the same power supply can be minimized.

[Simulation Result] FIGS. 6 and 7 are examples obtained by simulation calculation based on the above control method. 6 and 7 show the calculation results in the time axis direction, and the calculation conditions are as follows: traveling at a vehicle speed of 120 km / hr;
A lane change steering input of 30 deg [π / 6 rad] is applied, and the rated current of the electric steering angle actuator 6 is 20 A
When the power supply voltage is the normal voltage (14V) and the low voltage (8
The calculation result at time V) is shown. Here, in the relationship diagram between the power supply voltage VBL and the command correction rate Rs in FIG. 5, in this simulation, Va = 10 V and Vb = 8 V.

First, FIG. 7 shows the calculation result of the conventional example.
When the power supply capability of the power supply decreases and the responsiveness of the electric steering angle actuator 6 deteriorates as shown in FIG. C), the generated yaw rate dψ becomes smaller than the target yaw rate dψM as the movement state quantity target value as shown in FIG. Causes an error. This effect appears on the rear wheel steering angle (δrB) by the feedback (F / B) as shown in FIG. 3D, and the yaw rate becomes oscillating as shown in FIG. This gives the driver an uncomfortable feeling. Also,
An increase in the rear wheel steering angle corresponding to F / B due to a decrease in the power supply capability of the power supply, as shown by a hatched portion in FIG. 3D, is not only meaningless in terms of stability but also promotes deterioration of the power supply. Would.

FIG. 6 shows the calculation results of the present invention. Here, in the present calculation, at the time of the normal voltage, the command correction rate Rs = 1, so that the feedback control is 1
Since the command correction rate Rs = 0 when the voltage is low, the feedback control is not performed.

Therefore, when the voltage is low as shown in FIG. 6d), the rear wheel steering angle is not operated by the feedback control, so that the vibration of the generated yaw rate dψ with respect to the target yaw rate dψM is different from the conventional example of FIG. 7b). It can be seen that it has clearly decreased. Thereby, the discomfort experienced by the driver can be significantly reduced. In addition, when the power supply deteriorates as shown in FIG. 3D, the amount of operation of the meaningless F / B is reduced, so that adverse effects on other systems using the same power supply can be minimized.

Next, the effects will be described.

As described above, in this embodiment, the vehicle auxiliary steering which drives the electric steering angle actuator 6 using the auxiliary steering angle feedback operation amount δrB corresponding to the difference e between the yaw rate target value dψM and the generated yaw rate dψ. In the angle control device, a voltage sensor 11 that detects a power supply voltage state of an electric steering angle actuator 6 that electrically provides an auxiliary steering angle is provided,
The power supply voltage is monitored based on the detection value from the voltage sensor 11, and when it is determined that the power supply capability of the power supply is insufficient, the auxiliary steering angle feedback operation amount correction for reducing the auxiliary steering angle feedback operation amount δrB is performed. Since the device is provided with the unit 27, when the power supply voltage is reduced, the driver can feel uncomfortable and can prevent the influence on other systems using the same power supply.

Although the embodiment has been described with reference to the drawings, the specific configuration is not limited to the embodiment, and even if there are changes and additions without departing from the gist of the invention, the invention is included in the invention. It is.

For example, in the embodiment, an example of application to the rear wheel auxiliary steering angle control system has been described. However, the present invention can also be applied to a front wheel auxiliary steering angle control system and front and rear wheel auxiliary steering angle control systems.

In the embodiment, an example in which the yaw rate is used as the motion state quantity has been described. However, a motion state quantity such as a lateral acceleration, a lateral speed, or a yaw rate + lateral speed may be used.

In the embodiment, the example in which the auxiliary steering angle is controlled by feedforward control + feedback control is described. However, the present invention can be applied to a system in which the auxiliary steering angle is controlled only by feedback control.

[0051]

As described above, according to the present invention, there is provided a vehicle for driving an electric steering angle actuator using an auxiliary steering angle feedback operation amount corresponding to a difference between a target value and a detection value of a motion state amount. In the auxiliary steering angle control device, a power supply voltage state detecting unit that detects a power supply voltage state of an electric steering angle actuator that electrically provides an auxiliary steering angle, and monitors a power supply voltage to determine that the power supply capability of the power supply is insufficient. In this case, the device is provided with auxiliary steering angle feedback operation amount correction means for reducing the auxiliary steering angle feedback operation amount. The effect is obtained that the influence on other systems being used can be prevented.

[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 auxiliary steering angle control device according to the embodiment of the present invention is applied.

FIG. 3 is a block diagram showing an electronic control system centered on a controller of the apparatus according to the embodiment of the present invention.

4A and 4B are diagrams showing the state of the power supply voltage according to the embodiment of the present invention, wherein FIG. 4A shows the voltage fluctuation of the power supply voltage, and FIG. 4B shows the state after passing through a low-pass filter having a predetermined time constant τ. FIG. 5 is a diagram showing power supply voltage fluctuations of FIG.

FIG. 5 is a map diagram for obtaining a command correction rate from a power supply voltage according to the embodiment of the present invention.

FIG. 6 is a diagram showing a simulation result of the embodiment of the present invention.

FIG. 7 is a diagram showing a simulation result of a conventional example.

[Explanation of symbols]

 a vehicle state detection means b movement state quantity target value calculation means c actual movement state quantity detection means d auxiliary steering angle feedback operation amount determination means e electric steering angle actuator f power supply voltage state detection means g auxiliary steering angle feedback operation amount correction means

Continuation of the front page (51) Int.Cl. ⁶ identification code FI B62D 137: 00 (58) Field surveyed (Int.Cl. ⁶ , DB name) B62D 6/00 B62D 5/04 B62D 7/14

Claims (1)

(57) [Claims] 1. A vehicle state detection means for detecting a vehicle state; a movement state quantity target value calculation means for calculating a target value of a movement state quantity by using the vehicle state detection value as an input; Actual movement state amount detection means for detecting a movement state amount; and auxiliary steering angle feedback operation amount determination means for determining an auxiliary steering angle feedback operation amount according to a difference between the movement state amount target value and the actual movement state amount detection value. Power supply voltage state detection means for detecting a power supply voltage state of an electric steering angle actuator that provides an auxiliary steering angle by electric power; monitoring the power supply voltage, and determining that the power supply capability of the power supply is insufficient. An auxiliary steering angle feedback control device for a vehicle, comprising: an auxiliary steering angle feedback operation amount correction unit that reduces the auxiliary steering angle feedback operation amount.