JPH0569839A - Steering angle control device - Google Patents

Abstract

PURPOSE:To prevent under-steer and over-steer in turning braking and to improve round turning performance and running stability by reversing the modification direction at loose braking and rapid braking at modification of an auxiliary steering angle of a vehicle for auxiliary steering at least one of front and rear wheels according to deceleration at turning braking. CONSTITUTION:For auxiliary steering of a front wheel 2 and a rear wheel 2 through actuators 5 and 6, signals on a steering wheel turning angle theta, a car speed V, a stroke L, a lateral acceleration g and fore and aft acceleration G and ON/OFF of a brake are put into a controller 16 from each of sensors 17 to 22. The controller 16 executes a predetermined control program respectively for the front and rear wheels, and in the rear wheel auxiliary steering, an auxiliary steering angle is controlled on the same phase side as the front wheel at loose braking and on the opposite phase side at rapid braking (controlled reversely for the front wheel auxiliary steering) to improve steering characteristics of a vehicle in turning braking.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steering angle control device for optimizing a steering characteristic during turning braking in a vehicle having an auxiliary steering mechanism.

[0002]

2. Description of the Related Art As a conventional example of this type of steering angle control device, for example, there is one disclosed in Japanese Patent Laid-Open No. 60-92977. This conventional example has a hydraulic mechanism that operates during steering of the front wheels and assists the rear wheels by steering the rear wheels in the same steering direction as the front wheels when the vehicle is decelerated due to braking or the like. It is configured to steer in the phase direction, and by this rear wheel assist steering, it is possible to prevent oversteering of the steering characteristics of the vehicle and prevent tuck-in during turning braking.

By the way, in the above-mentioned conventional example, when the driver steps on the brake during turning, the magnitude of the braking force (deceleration) and the magnitude of the load movement between the front and rear wheels at that time are described in detail below. Depending on the relationship with the vehicle, the steering characteristics of the vehicle may become understeer or oversteer and may not be constant. That is, as shown by the solid line in FIG. 8, during cornering with high lateral acceleration in which both front and rear wheels have large slip angles, a large cornering force is generated in the tire and the cornering force reduction amount during braking becomes large. As indicated by the dotted line in Fig. 4, during low lateral acceleration turning with small front and rear wheels, a small cornering force is generated on the tire and the cornering force decrease during braking becomes smaller than during high lateral G turning. At that time, the size of the friction circle shown by the solid line and the dotted line in FIG. 8 greatly changes depending on the ground load of the tire, and the front wheel load increases and the rear wheel load decreases during deceleration. The size of the circle will change. When these requirements are summed up, when the brake pedal is operated during turning, the steer characteristic of the vehicle is oversteered with the increase of the front wheel load and the decrease of the rear wheel load during the slow braking with a small deceleration. At the time of large sudden braking, the slip angle of the front wheels becomes large and the tire lateral force of the front wheels is greatly reduced as shown by the solid line in FIG. 8, resulting in understeering.

[0004]

However, in the above-described conventional example, the rear wheel steering angle control is always performed to correct the rear wheel steering angle to the inside of the turning regardless of the magnitude of the deceleration during braking during the turning. Therefore, during slow braking, oversteering due to the braking can be prevented, but understeering is promoted during sudden braking, and the steer characteristic of the vehicle becomes strong understeer, which makes it difficult to secure turning performance during turning.

An object of the present invention is to solve the above-mentioned problem by determining the correction direction of the auxiliary steering angle according to the deceleration during turning braking.

[0006]

To this end, the first structure of the steering angle control device of the present invention is, as the concept is shown in FIG. 1, an auxiliary steering mechanism for auxiliary steering the rear wheels and a reduction of the vehicle. In a vehicle including deceleration detecting means for detecting a speed and steering angle control means for performing a rear wheel steering angle control for the auxiliary steering mechanism according to the detected deceleration, the vehicle is turning. Turning detection means for detecting, brake detection means for detecting braking operation by the driver, and when the driver performs a braking operation during turning, when the deceleration is slower than a predetermined value, the rear wheel steering angle is turned inward. 2 and the steering angle correction means for correcting the rear wheel steering angle to the outside of the turning at the time of sudden braking with the deceleration larger than a predetermined value. Further, the second configuration of the present invention is shown in FIG. As shown in the concept, an auxiliary steering mechanism for auxiliary steering the front wheels, In a vehicle including deceleration detection means for detecting both decelerations and steering angle control means for performing front wheel steering angle control for the auxiliary steering mechanism according to the detected decelerations, the vehicle is turning. When the driver's brake operation is performed while the vehicle is turning, the front wheel steering angle is set outside the turning range during slow braking with a deceleration smaller than a predetermined value. It is characterized by comprising steering angle correcting means for correcting the front wheel steering angle to the inward of the turning at the time of sudden braking that is corrected to one side and the deceleration is larger than a predetermined value.

[0007]

According to the first aspect of the present invention, when the driver makes a brake operation during turning, the steering angle correction means determines the steering angle control means based on the deceleration information from the deceleration detection means. Auxiliary steering mechanism for the rear wheels The rear steering angle of the rear wheel is corrected inward when the vehicle is gently braking, and outward when the vehicle is braking suddenly. At the same time, it is possible to prevent understeer from occurring during sudden braking, which improves turning performance and traveling stability during turning braking. Further, according to the second configuration of the present invention, when the driver performs a brake operation during turning, the steering angle correction means,
The steering angle control means determines the front wheel steering angle of the auxiliary steering mechanism for the front wheels, which is determined based on the deceleration information from the deceleration detection means. Therefore, understeering at the time of slow braking and at the same time oversteering at the time of sudden braking can be prevented, and the turning performance and traveling stability at the time of turning braking are improved.

[0008]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 3 shows an embodiment of the steering angle control device of the present invention.
Indicates front wheels and 2 indicates rear wheels, respectively. The front wheels 1 can carry out main steering as usual by transmitting steering inputs to the steering wheels (handles) 3 via the steering gears 4, and the case of the steering gears 4 can be stroked by the actuators 5 to make the main steering angle. It is possible to perform auxiliary steering up to α degrees. Further, the rear wheel 2 enables the auxiliary steering up to β degree by the stroke of the actuator 6 in the rear wheel steering mechanism. here,
In this embodiment, it is assumed that α degrees> β degrees. In addition to the actuators 5 and 6, the front / rear wheel auxiliary steering system is provided with an oil pump 7 as a pressure source common to both systems, and further with a flow dividing valve 12 and steering angle control valves 14 and 15. The oil pump 7 sucks the oil in the reservoir 8 and discharges it to the main circuit 9, and the flow dividing valve 12 thereby distributes the oil on the main circuit 9 to the front wheel auxiliary steering circuit 10 and the rear wheel auxiliary steering circuit 11.

The flow dividing valve 12 is constructed by elastically supporting a shuttle spool 12a at a neutral position by springs 12b and 12c, and pressure chambers 12d and 12e are defined at both ends of the spool 12a. These pressure chambers 12d and 12e are communicated with the main circuit 9 through the orifices 12f and 12g having different diameters formed in the spool 12a, and the lateral holes 12 also formed in the spool 12a.
Auxiliary steering circuit 1 via h, 12i and output ports 12j, 12k
Make them familiar with 1, 10. Therefore, the lateral holes 12h and 12i are adjusted in the degree of communication with the output ports 12j and 12k according to the stroke of the spool 12a that responds to the pressure in the pressure chambers 12d and 12e, respectively.
The following diversion function shall be fulfilled.

That is, focusing on, for example, the circuit 10, the required flow rate Q _f of the circuit 10 is determined as follows:
Q of the piston pressure receiving area S _A and the piston moving speed v
_f = S represented by _A × v, further, if the stroke of the actuator 5 d, the front-wheel steering frequency is f, since the moving velocity is v = 2π × f × d, the required flow rate of the circuit 10 Q
_f becomes Q _f = S _A × 2π × f × d. Further, the required flow rate Q _r of the circuit 11 is similarly obtained, and when the discharge amount Q _o of the pump 7 is Q _o = Q _f + Q _r , the distribution ratio for obtaining the required required flow rates Q _f and Q _r is the above-mentioned orifice. 12g, the diameter of the 12f Q _f / Q _o, obtained by set corresponding to the Q _r / Q _o. The shunt valve 12 can thus distribute the pump discharge amount Q _o to the circuits 10 and 11 to supply the required flow rates Q _f and Q _r . Further, when the circuit 10 or the circuit 11 has a pressure drop due to a change in the flow rate, the spool 12a of the shunt valve 12 moves rightward or leftward in the figure to reduce the opening degree of the lateral holes 12i or 12h, and the flow rate distribution ratio is disrupted. It is possible to prevent the pressure fluctuation of one system from affecting the other system. The rudder angle control is performed by controlling the rudder angle control valves 14 and 15 under the above-described configuration in which the pressure fluctuations of both systems do not interfere with each other.

The steering angle control valves 14 and 15 are pressure control valves, respectively, which are interposed between the auxiliary steering circuits 10 and 11 and the common drain circuit 13 and the actuators 5 and 6. The steering angle control valve 14 for front wheel auxiliary steering is a solenoid 14a,
The circuit is in the neutral position shown when 14b is off (not energized).
The entire amount of oil from 10 is returned to the drain circuit 13, and both chambers 5a and 5b of the actuator 5 are kept in a pressureless state. At this time, the actuator 5 is set to the neutral position by the built-in springs 5c and 5d,
The steering gear 4 is kept at a position where the front wheels 1 are not assisted by the steering. When solenoid 14a is on (energized), valve 14 is in chamber 5a
Is pressurized, the chamber 5b is drained, the actuator 5 is extended, and the steering gear 4 is moved to the right in the figure, whereby the front wheel 1 is assisted in the left turning direction within the α degree. Further, the valve 14 pressurizes the chamber 5b, drains the chamber 5a to cause the actuator 5 to contract when the solenoid 14b is on (energized), and causes the steering gear 4 to move to the left in the drawing, whereby the front wheel 1 Assist steering in the right-turning direction within α degrees.

The configurations of the steering angle control valve 15 and the actuator 6 for auxiliary steering of the rear wheels and their functions are similar to those of the steering angle control valve 14 and the actuator 5. That is, the rudder angle control valve 15 includes the solenoids 15a and 15b.
And the actuator 6 includes a chamber 6a, 6b and a built-in spring 6
It is equipped with c and 6d. A stroke sensor 19 for detecting the stroke L of the rear wheel side actuator 6 is also provided.
When both solenoids 15a and 15b are off (when not energized), valve 15 keeps both chambers 6a and 6b in a non-pressurized state, and when solenoid 15a is on (when energized), chamber 6a is pressurized. As a result, and when the solenoid 15b is turned on (when energized), the rear wheel 2 is steered in the corresponding direction within the β degree by the pressurization of the chamber 6b. The rear wheels 2 are steered by the mechanism for steering the rear wheels as described above.

Each of the solenoids 14a of the steering angle control valves 14, 15
14b, 15a, 15b are controlled by a controller 16 to be turned on / off, and this controller 16 includes a steering wheel 3
Steering angle sensor 17 to detect the steering angle (steering angle) θ
From the vehicle speed sensor 18 that detects the vehicle speed V, the signal L from the stroke sensor 19, the signal from the lateral acceleration sensor 20 that detects the lateral acceleration g, and the longitudinal acceleration sensor 21 that detects the longitudinal acceleration G. Traffic lights and brakes
The signals from the strap lamp switch 22 indicating ON and OFF are input respectively. The signals from the sensors 20 and 21 are filtered to remove noise.

The controller 16 includes an input detection circuit and
Arithmetic processing circuit and steering angle control executed by the arithmetic processing circuit
Circuit for storing programs and calculation results for computer
And an output circuit that supplies control signals to the steering angle control valves 14 and 15.
And the control of FIG. 4 described later based on the above input information.
Run a program to calculate the front and rear wheel steering angles and control the steering angle
Turn solenoids 14a, 15a and 15b of valves 14 and 15 on and off.
Signal I for controlling_Fa, I _Fb, I_RaAnd I_RbAnd output
The front and rear wheels are individually steered so that the steering angles are calculated. Note that
The target steering angle control of this example by this controller 16
Is being carried out on both the front and rear wheels.
You may make it implement | achieve only in any one of these.

FIG. 4 is a control program of a main routine in the controller 16, which is subjected to a timed interrupt processing at predetermined intervals by an operating system (not shown). First, the rear wheel assist steering will be described with reference to FIG. 4. In step 101, the state of the flag FLAG1 is checked. Prior to this check of FLAG1, FLAG1 is reset only during the first control of this program (FLAG1 =
0) so that step 101 always selects step 102 in the first time. In step 102, it is determined whether or not the stop lamp switch 22 is ON. When the determination is YES, the control advances to step 103 and thereafter. Note that when the above determination is NO, that is, when the vehicle is not braked, it does not correspond to the turning braking that is the target of the steering angle control according to the present program, so the control ends as it is.

By the way, the FLAG 1 sets the steering angle control of this embodiment to O as shown in the timing charts of FIGS. 7 (a) and 7 (b).
This flag indicates the area to be N (executed), and this FLAG1
1 becomes ₁ from the instant t 1 at which the driver depresses the brake to the instant t ₃ at which the longitudinal acceleration G generated by this depression becomes almost zero. FLAG1 is 0
Is when the brake is off and the longitudinal acceleration G is 0,
That is, before the instant t ₁ and after the instant t _{3 in} FIGS. 7 (a) and 7 (b). Therefore, when braking is determined to be YES in step 102, FLAG1 is set in the next step 103 (FLAG1 = 1).
Then, in step 104, the gain g ₁ is read by referring to the map of FIG.

As illustrated in FIG. 5, the gain g ₁ is determined based on the magnitude of the lateral acceleration g at the start of the brake operation (stepping on) (instant t _{1 in} FIGS. 7 (a) and 7 (b)). In the region where the lateral acceleration g is a predetermined value G ₁ or less, the gain g ₁
= 0, g is set to a positive value that linearly increases in response to an increase in lateral acceleration g in the region where G exceeds G ₁ .
Take a value in the range of 0 ≦ g ₁ ≦ 1. In the map of FIG. 5, when the lateral acceleration g in one of the right turn and the left turn of the vehicle is set to be positive, the other becomes negative. Therefore, the absolute value of g as the lateral acceleration on the horizontal axis = | g | Shall be used.

In the next step 105, the gain g ₂ is read by referring to the map of FIG. Where gain g
₂ is determined based on the magnitude of the longitudinal acceleration G, for example, as shown by the solid line in FIG. 6, and in the region where the longitudinal acceleration G is a predetermined value G ₂ or less, the gain g ₂ = 0 and G is G ₂ A positive value in the range of 0 <g ₂ ≦ 1 is exceeded in the area until the predetermined value G ₃ is exceeded, and 0> g ₂ ≧ − in the area in which G exceeds G _3.
The value is set to be a negative value in the range of 1, and the gain g ₂ eventually takes a value in the range of −1 ≦ g ₂ ≦ 1. Note that FIG.
It is desirable to appropriately set the map of the gain g ₂ in accordance with the steer characteristic of the vehicle to be applied. For example, the longitudinal acceleration G which gives the maximum value 1 of the gain g ₂ shown by the solid line in FIG.
Set to.

Based on the gains g ₁ and g ₂ obtained as described above, in the next step 106, the rear wheel auxiliary steering angle δ _rB
Is calculated by δ _rB = g ₁ · g ₂ · δ _rB0 / (1 + T _S ) ---- (1) (where δ _rB0 ; the maximum value of the rear wheel auxiliary steering angle determined by mechanical constraints, T _S ; Delay time constant).
As is clear from the equation (1), the gain g ₁ takes a positive or zero value, the gain g ₂ takes a positive, 0 or negative value, and δ _rB0 / (1 + T _S ) becomes a constant. , The rear wheel steering angle δ _rB will take a positive, zero or negative value. Note that
The reason for providing the delay time constant T _S in the equation (1) is to prevent the driver from feeling a sense of discomfort by preventing the vehicle behavior from picking up when the counter steer is operated. The rear wheel steering angle δ _rB thus obtained is output in step 107, and the rear wheel assist steering based on this δ _rB is performed.

In the control of the second and subsequent times in this program, since the FLAG1 = 1 since execution of step 103, the determination in step 101 is YES and step 108 is selected. In step 108, it is determined whether or not the stop lamp switch 22 is ON, and the stop lamp switch 22 is turned on, as shown in FIGS.
Since the depression of the brake continues for a certain period of time as indicated by the instants t _{1 to} t ₂ of, the determination is YES until the instant t ₃ . In that case, the control advances to step 105, where the gain g ₂ is read based on the longitudinal acceleration G at that time with reference to the map of FIG. Further, the instants t _{2 to} t in FIGS. 7 (a) and 7 (b)
_{During 3 as} well, since the determination of whether or not G = 0 executed in step 109 following the ON of step 108 is NO, the control advances to step 105, and in any of the above cases, step 105
Then, based on the gain g ₂ read this time and the gain g ₁ (default value) already read in step 104, step 10
In step 6, the rear wheel steering angle δ _rB is calculated, and in step 107 δ _rB is output.

Note that the determination in step 109 is YES because the longitudinal acceleration G becomes 0 and the stop lamp switch 22 becomes OF as in the moment t ₃ in FIGS. 7 (a) and 7 (b).
If it becomes F, in other words, it is during non-braking. In that case, in step 110 FLAG1 is reset (FLAG1 = 0), then in step 111 the rear wheel steering angle δ _rB is _set to 0, and δ _rB
Is output in step 107.

The operation of the rear wheel steering angle control will be described in detail with reference to FIGS. 7 (a) and 7 (b). Here, FIG. 7 (a) shows an example in which the longitudinal acceleration G, which is a physical quantity corresponding to the deceleration of the vehicle, is smaller than a predetermined value G ₃ , and this is the case during slow braking when the deceleration is smaller than the predetermined value. Correspondingly, similarly, FIG. 7B corresponds to the case of sudden braking in which the longitudinal acceleration G is larger than the predetermined value G ₃ . First, at the time of slow braking in FIG. 7A, the lateral acceleration g exceeds the predetermined value G ₁ before the instant t ₁ while the vehicle is turning due to the driver's operation of the steering wheel, but at the instant t ₁
Since the braking operation is not performed until then, NO of step 101-NO of step 102 of FIG. 4 is executed, the control of this example is not applied, and the rear wheel steering angle δ _rB becomes zero. When the stop lamp switch 22 is turned on by the braking operation at the instant t ₁ , the gain g ₁ read in step 104 after the flag FLAG1 is set in step 103 is as shown in FIG. The value has a value corresponding to the absolute value of the hour g. Therefore, this gain g ₁ has a positive value of 0 when the vehicle is not turning and 0 <g ₁ ≦ 1 when the vehicle is turning, and the step 104 for obtaining this g ₁ functions as a turning state detecting means. Since the longitudinal acceleration G generated by the braking operation at the instant t ₁ corresponds to the deceleration of the vehicle, the gain g ₂ is read based on this longitudinal acceleration G Step 10
5 functions as a deceleration detecting means. In addition, step 102 for checking ON / OFF of the stop lamp switch 22
It goes without saying that step 108 and step 108 function as brake detection means.

Using the above gains g ₁ and g ₂ , step 106
The rear-wheel steering angle δ _rB calculated in step (1) becomes 0 because at least one of the gains g ₁ and g ₂ becomes 0 until the instant t _{1 in} the case of slow braking in FIG. NO-102 YES-
The loop of 103-104-105-106-107 is executed, and thereafter, until the instant t ₂ when the stop lamp switch 22 is turned off, the loop of YES-105-106-107 of YES-108 of step 101 is executed and FLAG1 Is reset until the instant t ₃ when is reset
Since the loop of 101 YES-108 NO-109 NO-105-106-107 is executed, the gains g ₁ and g ₂ are both positive, so a positive value is obtained from instant t ₁ to t _3. After the instant t ₃ , YES-110 of step 101, NO-109 of step 101, YES-110-111-107.
Is executed and the gain g ₂ becomes 0, and thus becomes 0. Thus, giving a positive rear wheel steering angle at the time of gentle braking during turning between instants t ₂ and t ₃ means steering the rear wheels in the same phase direction as the front wheels, and the rear wheel steering angle δ _rB Is corrected inward of the turn, and this step 106 functions as a rudder angle correction means. By such rear wheel steering angle control, it is possible to prevent oversteering of the steer characteristic of the vehicle during slow braking.

Meanwhile, at the time of sudden braking of FIG. 7 (b), although the rear-wheel steering angle [delta] _rB in the same manner as when to time t ₁ and instant t ₃ thereafter light braking becomes zero, instant t ₁ ~t The rear wheel steering angle control between ₃ becomes different from that at the time of the above slow braking. That is, from the instant t _{1 in} FIG. 7 until the instant t _{11 at} which the longitudinal acceleration G reaches the predetermined value G ₃ , the gain g ₂ takes a positive value as shown by the solid line in FIG. _rB = g ₁ · g ₂ · δ _rB0 / (1 + T _s ) _-The rear wheel steering angle δ _rB obtained by (1) has a positive value, but the instant t ₁₁
After that, until the instant t ₁₂ when G becomes G ₃ again, the gain g _2
Takes a negative value, so δ _rB becomes a negative value. Therefore, the change of the rear wheel steering angle δ _rB between the instants t _{1 to} t ₃ is the instant t _{1 to} t _3.
Between ₁₁ and the instants t _{12 to} t ₃ , the rear wheels are corrected inward so as to steer in the same phase direction as the front wheels, but at instant t ₁₁
During the sudden braking between t _{12 and} t ₁₂ , the rear wheels are corrected to the outside of the turning so as to steer in the opposite phase direction to the front wheels, and this step 106 functions as a steering angle correction means (note that in this way, be given a wheel steering angle after the phase direction, and FIG. 7 (b) to the instant t ₁₁ the rear wheel steering angle [delta] _rB since the instant t ₁₁ are steered rear wheels on the phase side as shown ~t It becomes a positive value between ₁₂ , so the rear wheels are not steered in reverse phase). By such rear wheel steering angle control, it is possible to prevent the steer characteristic of the vehicle at the time of sudden braking from being understeered as in the conventional example described above. The steering characteristics of the vehicle are improved during both sudden braking, and the turning performance and traveling stability can be improved.

Regarding the front wheel assist steering, δ _fB in steps 107 and 111 in the control program of FIG. 4 is replaced with the front wheel assist steering angle δ _fB , and the arithmetic expression in step 106 is δ _fB = g ₁ · g ₂ · δ _fB0 / (1 + T _S ) ---- (2) (where δ _{fB0 is} the maximum front steering wheel angle determined by mechanical constraints, T _{S is the} delay time constant), and the gain g ₂ is indicated by the dotted line in Fig. 6. As described above, the characteristics are set to be the same as those of the rear wheels with the positive and negative (polarity) reversed, and the other configurations are the same as those of the rear wheels. In this way, the front wheel steering angle δ _fB is corrected outward during turning during gentle braking during turning, preventing understeer of the steering characteristics of the vehicle, and the front wheel steering angle δ _fB is corrected inside during turning during sudden braking. Oversteering of the steerability of the vehicle is prevented, and in any case, the steerability of the vehicle is improved and the turning performance and traveling stability are improved.

[0026]

As described above, in the steering angle control device of the present invention, in the first configuration as described above, the auxiliary steering mechanism for the rear wheels is used when the correction direction of the auxiliary steering angle is determined according to the deceleration during turning braking. Since the rear wheel steering angle is corrected to the inside of the turn during gentle braking and to the outside of the turn during sudden braking, the above-described oversteer during slow braking is prevented and understeer during sudden braking is also prevented. Can also be prevented,
The turning performance and running stability during turning braking are improved. Further, in the second configuration of the present invention, when determining the correction direction of the auxiliary steering angle, the front steering angle of the auxiliary steering mechanism of the front wheels is corrected to the outside of the turning when the braking is slow, and the turning is performed when the braking is suddenly applied. Since the correction is made inward, it is possible to prevent understeer during slow braking and also prevent oversteer during sudden braking, thereby improving turning performance and running stability during turning braking.

[Brief description of drawings]

FIG. 1 is a conceptual diagram of the present invention.

FIG. 2 is a conceptual diagram of the present invention.

FIG. 3 is a system diagram showing an embodiment of a steering angle control device of the present invention.

FIG. 4 is a flowchart showing a control program for front and rear wheel steering angle control by the controller in the example.

FIG. 5 is a diagram illustrating a characteristic of a gain g ₁ used in the same example.

FIG. 6 is a diagram illustrating a characteristic of a gain g ₂ used in the same example.

7A and 7B are timing charts for explaining the operation of the example.

FIG. 8 is a diagram for explaining steer characteristics of the vehicle.

[Explanation of symbols]

 1 front wheel 2 rear wheel 3 steering wheel (handle) 5 actuator 6 actuator 16 controller 17 steering angle sensor 18 vehicle speed sensor 20 lateral acceleration sensor 21 longitudinal acceleration sensor 22 stop lamp switch

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location B62D 113: 00 137: 00

Claims (2)

[Claims] 1. An auxiliary steering mechanism for assisting steering of a rear wheel, a deceleration detecting means for detecting a deceleration of a vehicle, and a rear wheel steering angle control for the auxiliary steering mechanism according to the detected deceleration. In a vehicle equipped with a steering angle control means, a turning detection means for detecting that the vehicle is turning, a brake detection means for detecting a brake operation of the driver, and a braking operation of the driver during turning. A steering angle correction means for correcting the rear wheel steering angle inward when the deceleration is slower than a predetermined value, and for correcting the rear wheel steering angle outward when the braking is faster than the predetermined value. A rudder angle control device, which is characterized in that 2. An auxiliary steering mechanism for assisting steering of the front wheels, a deceleration detecting means for detecting a deceleration of a vehicle, and a steering angle for performing front wheel steering angle control for the auxiliary steering mechanism according to the detected deceleration. In a vehicle equipped with a control means, a turning detection means for detecting that the vehicle is turning, a brake detection means for detecting a braking operation of a driver, and a braking operation performed by a driver during a turning operation are reduced. A steering angle correcting means for correcting the front wheel steering angle to the outside of the turning when the speed is slower than a predetermined value, and for correcting the front wheel steering angle to the inward of the turning when the deceleration is faster than the predetermined value. A characteristic steering angle control device.