JP2992357B2 - Vehicle motion characteristic correction device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle for pulling back within limits by performing control equivalent to that of a skilled driver when the vehicle exceeds a normal motion limit such as spin, drift, and understeer. The present invention relates to a motion characteristic correction device.

[0002]

2. Description of the Related Art A US patent "Adaptive Vehicle" filed by GM (US Pat. No. 4,829,434R7)
4,789, registered on May 9, 1989) detects the driver's "operation" state, "environment" state such as weather and inter-vehicle distance, and "running" state such as vehicle speed and acceleration with sensors. A knowledge base is constructed for the three basic states, the optimal conditions are determined using the knowledge base, and integrated feedback control is performed on the vehicle.

[0003]

The control disclosed in the above-mentioned U.S. Patent is a system for improving a turning limit of a vehicle, and for some reason, the vehicle slips over the limit and starts spinning. , Control effect cannot be expected.

Here, in the vehicle kinematics, when the vehicle skids beyond the turning limit and spins, the steering wheel is returned to the neutral position in the opposite direction to the turning direction, or the steering wheel is moved further in the direction opposite to the neutral position. It is a well-known advanced operation to reduce side slips by increasing the number of wheels (counter steer), and to lock the rear wheel only by turning the side brake and turning with a small radius (spin turn) when cornering can not be completed due to understeer Technology. However, it is very difficult to precisely control the required amount of counter steer and spin turn, and it is difficult for anyone except specially trained people to do it.

[0005] It is an object of the present invention to provide a vehicle motion characteristic correction device that performs control equivalent to that of a skilled driver without disturbing the driver's intention.

[0006]

Means for Solving the Problems In order to achieve this object,
The vehicle dynamics characteristic correcting device according to the present invention is disclosed in claims.
It is characterized by what is described in each claim of
Is a vehicle according to the invention of claim 1 as an independent claim.
The motion characteristic correction device stores a steering angle detection unit, a brake hydraulic pressure detection unit, a throttle opening degree detection unit, a vehicle motion state detection unit, and a vehicle motion characteristic serving as a reference. A reference vehicle movement characteristic state storage means, a steering angle detected by the steering angle detection means, a brake oil pressure detected by the brake oil pressure detection means, a throttle opening detected by the throttle opening detection means, and a detection of the vehicle movement state. Means for predicting the next vehicle motion state based on the vehicle motion state detected by the means, the steering angle detected by the steering angle detection means, the brake oil pressure detected by the brake oil pressure detection means, and the throttle opening The throttle opening detected by the detection means, the vehicle movement state detected by the vehicle movement state detection means, and the reference vehicle movement characteristic state storage means are stored. Reference vehicle motion characteristics, and reference vehicle motion state prediction means for predicting the next reference vehicle motion state, steering angle control means, brake oil pressure control means, throttle opening degree control means, and gear position and control means, in a vehicle for chromatic and control means, the maximum differential limiting torque of the differential of the drive wheel, the norms vehicle motion Laid
The reference vehicle motion characteristics stored in the sexual state storage means are as follows:
Various steering angles and various brake fluids corresponding to arbitrary initial values
Pressure and various throttle opening degrees
If the vehicle motion state predicted by the vehicle motion state prediction means is expected to significantly deviate from the reference vehicle motion state predicted by the reference vehicle motion state prediction means, In order to reduce the deviation between the vehicle motion state and the vehicle motion state detected by the vehicle motion state detection means, in addition to the driver's steering, braking, and throttle operation, the steering angle control means and the brake hydraulic pressure control means One or more than one or more of the steering angle, brake oil pressure, throttle opening, gear position, and maximum differential limiting torque of the drive wheel differential device are controlled by the throttle opening control means and the gear position control means. Characterized in that the user is controlled . Also
Similarly, a vehicle motion characteristic correction device according to the invention according to claim 7 is provided.
Location includes means for detect the steering angle, to detect the brake hydraulic pressure
, Means for detecting a throttle opening, and vehicle motion
State detection means and memorized vehicle motion characteristics as a reference
Reference vehicle motion characteristic state storage means,
The brake oil pressure detected by the oil pressure detecting means and the slot
Throttle opening detected by the throttle opening detecting means and the vehicle operation.
The vehicle motion state detected by the motion state detection means and the reference vehicle
Reference vehicle motion characteristics stored in the motion characteristics state storage means
Reference vehicle motion to predict the reference vehicle motion state
State prediction means, steering angle control means, and brake hydraulic pressure
Control means, throttle opening degree control means, and gear position.
And the maximum differential limiting torque of the drive wheel differential.
And control means for the vehicle.
The reference vehicle motion characteristics stored in both motion characteristic state storage means
The characteristics refer to various steering angles and various brakes corresponding to any initial value.
Standard for rake hydraulic pressure and various throttle openings
Response of various vehicle motion states of the vehicle,
The vehicle movement state detected by the state detection means is based on the reference vehicle operation.
The reference vehicle motion state predicted by the motion state prediction means and significant deviation
If there is a difference, the reference vehicle motion state and the vehicle motion
Reduce the deviation from the vehicle motion state detected by the state detection means
Driver steering, braking, throttle
In addition to the operation, the steering angle control means and the brake hydraulic pressure control
Means, throttle opening control means and gear position control means
The steering angle, brake oil pressure, throttle opening, gear
Maximum differential control of the positioning or drive wheel differential
One or more than one person with limited torque or all persons
Is controlled.

[0007]

According to the above-mentioned feature, when the vehicle exceeds the motion limit such as spin, drift, and understeer, it can be returned to the limit by performing the same control as a skilled driver, thereby avoiding danger. Connect.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment in which the present invention is applied to a front engine, rear drive, automatic transmission vehicle with front two-wheel steering will be described with reference to the drawings.

FIG. 1 is a diagram showing the overall configuration of the apparatus of this embodiment. This device includes an engine 1, a right front wheel 2a,
Left front wheel 2b, right rear wheel 2c, left rear wheel 2d, wheel speed sensors 3a, 3b, 3d for each wheel, brakes 4a for each wheel,
4b, 4c, 4d, a steering mechanism 5, each wheel suspension mechanism 6a, 6b, 6c, 6d, a control differential 7, a steering 8, an accelerator pedal 9,
It comprises a brake petal 10, a steering angle control unit 11, a throttle control unit 12, a brake oil pressure control unit 13, a transmission control unit 14, a 6-DOF motion sensor 15, and a control unit 16.

The wheel speed sensors 3a, 3b, 3c, 3d are:
It is composed of a detection gear that rotates with each wheel and a magnetic pickup. The magnetic pickup outputs a pulse train corresponding to the wheel rotation angle. By measuring the pulse interval, the wheel speed at each rotation angle of the wheel can be detected.

The brakes 4a, 4b, 4c, 4d of each wheel
Provides a braking force to each wheel and also serves as a sensor for the brake line pressure during operation.

The suspension mechanism 6a includes a stroke sensor 61a (not shown) in a damper or the like (not shown), and can detect a stroke amount of the wheel suspension mechanism during traveling. Other suspension mechanism 6
b, 6c and 6d also have similar stroke sensors. Thus, the roll angle and the pitch angle of the vehicle can be detected. At the same time, the camber angle between the tire and the road surface changes,
An alignment change such as a toe change can be detected.

The control differential 7 is a differential gear in which a hydraulic differential wet multiple disc clutch for limiting a differential is incorporated in a differential gear, and is capable of controlling the maximum differential limiting torque of the right and left rear wheels by electronic control. Are known. Thereby, regardless of the wheel speed difference and the driving torque of the left and right rear wheels, the control can be freely performed from the state of the differential gear without the normal differential limitation to the lockup state in which the left and right rear wheels are directly connected.

FIG. 2 is a diagram showing the configuration of the steering angle control unit 11. As shown in FIG. The steering angle control unit 11 includes an actual steering angle encoder 111 that detects an actual steering angle, a gear box 112 that reduces the rotation of the steering motor 113, and a wet multi-plate clutch 114.
A gear box 116 for reducing the rotation of the steering feel correction motor 115, a steering angle encoder 117 for detecting the steering angle of the driver, an actual steering angle control unit 118, and a steering feel correction unit 119. It is configured. Hereinafter, the operation will be described. When the driver turns the steering 8, the steering angle encoder 117 is turned on.
Detects the steering angle by the control unit 1
Enter 6 The control unit 16 combines the steer steering angle and various information and outputs a steering angle command to the actual steering angle control unit 118. The steering motor 113 is a kind of a servomotor composed of an electric motor, and makes the detection value of the actual steering angle encoder 111 follow the steering angle command of the control unit 16. The steering mechanism 5 has a rack and pinion structure, and when the steering shaft 5 'rotates, the tire angle changes. The actual steering angle control unit 118 includes an actual steering current detection sensor 1182 in addition to a power transistor 1181 for current control. Generally, the output torque of a motor (electric motor) is proportional to the flowing current.
Now, by detecting the current input from the battery to the steering motor 113 with the actual steering current detection sensor 1182, the torque required for causing the actual steering angle to follow the steering angle command, that is, the reaction force from the road surface can be detected. . In accordance with the detected reaction force from the road surface, the control unit 16 feeds back an appropriate steering feel to the driver through the steering feel correction unit 119, the steering feel correction motor 115, and the steering 8. In addition, the steering angle control unit 11 includes a wet multi-plate clutch 114.
When each motor fails, the clutch is connected to directly connect the steering shaft 5 ′, and the driver can directly control the steering angle by the steering 8. At this time, the gear ratios of the gear boxes 112 and 116 must be set so that the driver can easily turn the steering wheel.

FIG. 3 is a diagram showing the structure of the throttle control unit 12, and FIG. 4 is a diagram showing the structure of the differential mechanism in FIG. Wire 1 connected to accelerator petal 9
Reference numeral 20 is fixed to the differential structure 122 as shown in FIG. Now, when the accelerator petal 9 is depressed, if the servomotor 124 is stopped, the throttle valve 121 rotates together with the differential structure 122, and performs a movement equivalent to that of a normal throttle structure. The throttle opening is detected by the throttle position sensor 123,
Is input to Next, a case where the servo motor 124 rotates will be described. Now, when the accelerator petal 9 is fixed and the servo motor 124 rotates counterclockwise, the throttle valve 121 is rotated clockwise (servo motor 1) by the differential structure constituted by the bevel gear of FIG.
When the servo motor 124 rotates clockwise, the slot valve 121 rotates counterclockwise. Therefore, by controlling the rotation angle of the servomotor 124, the throttle opening can be controlled independently of the driver's accelerator operation. The control unit 16 combines the throttle opening detected by the throttle position sensor 123 with various kinds of information, and controls the throttle opening accurately using the servomotor 124. In the unlikely event that the servomotor fails, the throttle valve 121 can be operated by the accelerator petal 9, so that normal operation is not hindered.

FIG. 5 is a diagram showing a configuration of one wheel of the brake hydraulic control unit 13. As shown in FIG. The brake oil pressure control unit includes a servo motor 132 connected to the brake petal 10 by a link mechanism 131, a master cylinder 133, a master oil pressure sensor 134, a brake oil pressure control valve 135, and each wheel oil pressure sensor 136. . The link mechanism 131 is configured to reliably transmit the input from the brake petal 10 and the servo motor 132 to the master cylinder 133 and not transmit the input from the servo motor 132 to the brake petal side. The control unit 16 includes a master oil pressure sensor 13 provided on the master cylinder 133.
From 4, the deceleration required by the driver is estimated. In the present embodiment, the deceleration is estimated based on the hydraulic pressure of the master cylinder generated when the driver depresses the brake pedal 10. However, a brake petal position sensor is provided on the brake petal, and the deceleration required by the driver is determined from the displacement. It can also be estimated. The control unit 16 further combines various kinds of information with the deceleration required by the driver, calculates independent hydraulic control commands for the four wheels necessary to obtain the estimated deceleration, and The brake hydraulic pressure of each wheel is controlled so that each wheel brake pressure detected by the hydraulic pressure sensor follows this command. Even when the driver does not step on the brake, if the control unit 16 determines that a braking force is necessary, for example, by entering a corner at an overspeed, the servo motor 132 operates the link mechanism 131.
To transmit the force to the master cylinder 132 so that the same state as when the driver depresses the brake pedal 10 can be created.

FIG. 6 shows the configuration of the six-degree-of-freedom motion sensor 15. The six-degree-of-freedom motion sensor 15 is disposed on the vehicle as shown in FIG. Acceleration sensors (linear acceleration sensors) 151
a, 151b, 151c, 151d, 151e, 151
f, a multiplier 152, a conversion circuit 153, two-stage integration circuits 154 and 155, and a differentiation circuit 156. As is generally well known, the degrees of freedom in the vehicle motion include the translational motion in the x-axis direction, the y-axis direction, and the z-axis direction, as well as the rotational motion (rolling) around the x-axis and the rotational motion (rolling) around the y-axis. Pitching) and rotational movement (yaw) around the z-axis. Since these movements are formed by being coupled with each other, the information actually measured by the acceleration sensor includes all components having six degrees of freedom. Therefore acceleration a _x in the x-axis direction, speed v _x, acceleration a _y in the y-axis direction, speed v _y, the acceleration in the z-axis direction a _z,
The velocity is v _z , the rotation (rolling) angular acceleration around the x axis is α _x , the angular velocity is ω _x , the rotation (pitching) angular acceleration around the y axis is α _y , the angular velocity is ω _y , and the rotation around the z axis (yaw) ) Angular acceleration is α _z , angular velocity is ω _z, and six acceleration sensors 151a, 151b, 151c, 151d, 1
The detected values detected by 51e and 151f are G _a , G
_{b, G c, G d,} G e, when the G _f, for example, an acceleration a _x in the x-axis direction, the following relationship for rotation (pitching) angular acceleration alpha _y of y-axis around.

[0018]

(Equation 1)

[0019]

(Equation 2)

In the six-degree-of-freedom motion sensor 15, the multiplier 1
52, the conversion circuit 153, and the integration circuit 154 make such calculation possible. The output from the integration circuit 154 becomes speed and angular velocity information, the output from the integration circuit 155 becomes position information, and the output from the differentiation circuit 156 becomes jerk information, which is output to the control unit 16. The control unit 16 uses these pieces of information to
By grasping the vehicle motion state and adding driving operation information such as the driver's steering angle, throttle opening, and brake oil pressure, and solving the motion equation specific to the target vehicle, predicting future vehicle motion and controlling at the same time By solving the inherent motion equation of the target vehicle (reference vehicle) to follow the vehicle, the reference vehicle motion is also predicted.

FIG. 8 shows a vehicle trajectory when the vehicle makes a high-speed turn, causes a sudden change in behavior, and falls into a spin state.
This shows the steering angle. FIG. 9 shows the vehicle trajectory and steering angle when the vehicle makes a high-speed turn at the same corner as in FIG. 8 and changes behavior, but avoids spin using counter steer and escapes from the corner.
8 and 9, the states of (a) and (b) are the same. FIG. 10 shows a two-dimensional mechanical balance when the vehicle is turning without skidding, and FIG. 11 shows a two-dimensional mechanical balance when the vehicle is skidding while turning. FIG. 12 shows the dynamic balance in two dimensions during countersteering.
Shown in

[0022] The vehicle, left and right front wheels, the cornering force C _fl occurring rear left and right _{wheels, C fr, C rl, C} rr and the driving force F acting on the rear left and right wheels in the case of increasing the throttle opening
_arl, F _arr and, the left and right front wheels when the brakes are applied, the braking force F _bfl acting on the rear left and right wheels, F _bfr, F _br1, F
_{The brr} and the centrifugal force acting on the center of gravity of the vehicle act to balance the translational motion in the y-axis direction and the rotational motion about the z-axis. Now, the vehicle is turning at a constant speed V, the weight of the vehicle is m, the moment of inertia around the center of gravity is I, the effective length from the center of gravity of the vehicle to the front wheels is l _f , and the effective length from the rear wheels to l is l. _r , the front wheel tread is l _ft , the rear wheel tread is l _rt , the vehicle center-of-gravity skid angle defined by tan β = v _y / v _x is β, and the steering angle is δ, the motion in this state is as follows. Can be described.

Y-axis direction

[0024]

(Equation 3)

Around the z axis

[0026]

(Equation 4)

The cornering force is determined by the sideslip angle of the wheels with respect to the traveling direction of the vehicle (the direction of the speed V), and is controlled by the driver at the front wheels by the steering angle. Now, the cornering power of the front left and right wheels K _fl, K _fr, the cornering power of the rear wheels K _rl, K _rr
Then

[0028]

(Equation 5)

[0029]

(Equation 6)

[0030]

(Equation 7)

[0031]

(Equation 8)

## EQU1 ## β _fl , β _fr , β _rl , and β _rr are the sideslip angles of the front left and right wheels and the rear left and right wheels, respectively. Here, for simplicity, it is assumed that the sideslip angles of the front left and right wheels are equal, and the sideslip angles of the rear left and right wheels are equal.

The braking / driving force (general term for braking force and driving force, the same applies hereinafter) is controlled by the driver by means of a brake and an accelerator. As is well known, the sum of the absolute value of the cornering force and the absolute value of the braking / driving force at which the tire can generate at the time of the limit running is constant unless the friction coefficient between the road surface and the tire changes. Now, assuming that the fixed values of the front left and right wheels are F _l and F _r , and that of the rear wheels are R _l and R _r , the following formula is established at the time of running at the limit.

[0034]

(Equation 9)

[0035]

(Equation 10)

[0036]

[Equation 11]

[0037]

(Equation 12)

[0038]

(Equation 13)

[0039]

[Equation 14]

[0040]

(Equation 15)

[0041]

(Equation 16)

In FIG. 10, the traveling direction of the vehicle (direction of the speed V) coincides with the x-axis direction, and the vehicle does not have a velocity component v _y in the y-axis direction. That is, β = 0. Next, FIG. 11 shows a state where β <0.
The reason why the rear wheel is swung out of the corner is to obtain a wheel side slip angle for obtaining a cornering force commensurate with the centrifugal force because the steering wheel has no steering mechanism. From this state, if the absolute value of the braking / driving force of the rear wheel is increased by further stepping on the access or applying a brake only to the rear wheel, the rear wheel exceeds the limit state before the front wheel. The equations of motion of the translational motion in the y-axis direction and the rotational motion about the z-axis at this time are as follows.

[0043]

[Equation 17]

Around the z axis

[0045]

(Equation 18)

Is as follows. The third and sixth terms of (Equation 18) represent the difference between the braking and driving forces of the front left and right wheels and the difference between the braking and driving forces of the rear left and right wheels, respectively. Therefore, as described above, the braking force of the front left and right wheels is independently controlled by the brake hydraulic control unit 13, and the braking / driving force of the rear left and right wheels is controlled by the brake hydraulic control unit 13 and the control differential 7. , The rotation about the z-axis can be positively controlled.

As can be seen from ( _Equation 17), when the left and right rear wheel braking / driving force (F _arl −F _brl ) and (F _arr −F _brr ) are increased, the third and fourth terms of ( _Equation 17) become And the sideslip angle β increases. Furthermore, the fourth and fifth terms of (Equation 18) increase, the rotational angular acceleration dω _z / dt about the z-axis also increases, and a spin state occurs. Here, in order to avoid this spin, as can be seen from (Equation 17) and (Equation 18), the braking / driving force is controlled so as not to be excessive, and at the same time, the steering angle δ is reduced and the negative region (turning direction) is reduced. Opposite to
In other words, it is effective to perform control up to counter-steering) to make the rotational moment about the z-axis by the cornering force generated by the front wheels zero or negative (reverse) (FIG. 12).

FIG. 13 shows a method of realizing the above control in the present invention for the front wheel having a steering function, and then for the rear wheel. In (Equation 5) and (Equation 6),
_{β + 1 f · ω z /} V is lateral slip angle of the front wheels tread central, can be detected by processing the information from the 6 DOF motion sensor 15 in the control unit 16. now,
Taking the sideslip direction of the center of the front wheel tread on the vertical axis, taking the cornering force on the horizontal axis, and taking the angle between the sideslip angle vector at the center of the front wheel tread and the front wheels as δ ′, and considering the steering angle vector as shown in FIG. 'Is the steering angle that produces the actual cornering force. An orthographic projection of this steering angle vector onto the cornering force axis is considered to be a cornering force. Now, the steering angle δ '
When the steering angle increases, the cornering force reaches a maximum value at a certain steering angle, and thereafter decreases, so that the steering angle vector draws a locus as shown in FIG. In FIG. 13, the state (a) is a case where the normal state is controlled, and the steering angle δ ′ is positive and the cornering force is also positive. The state in which the steering angle is controlled between the states (b) and (c) is a characteristic of the present invention.
δ ′ is controlled to zero, and the cornering force is set to zero. Further, in (c), by making δ 'negative, a cornering force opposite to the turning direction is generated. This is equivalent to realizing countersteering, which is one of the driving operations that can be performed only by a skilled driver.

Next, the rear wheel will be described. In the normal driving states (d) and (e), the driving force _Fa or the braking force _Fb
The cornering force decreases with an increase in the wheeling force (f) in which the tire driving force is excessive, and the wheel locking state (g) in which the tire braking force is excessive, and the cornering force becomes zero. In the present invention, the vehicle speed detected by the six-degree-of-freedom motion sensor 15 and the wheel speed sensor
The braking / driving force is controlled by the brake hydraulic pressure control unit 13 and the throttle control unit 12 using the wheel speeds of the respective wheels detected by the control, and the cornering force is controlled. The method of controlling the cornering force by controlling the braking force is as follows.
Needless to say, it can be applied to the front wheel having a brake.

In the present invention, the control unit 16 controls the vehicle motion information obtained from the six free motion sensors 15, the respective wheel speeds obtained from the wheel speed sensors 3 of the respective wheels, and the steering angle information obtained from the steering angle control unit 11. , Throttle control unit 1
2 using the throttle opening information obtained from the second control unit and the brake oil pressure information obtained from the brake oil pressure control unit 13. As described above, the counter steer is actively used, the brake is applied only to the rear wheel, and the throttle is excessively opened. By controlling the cornering force of each wheel independently by rotating the drive wheels, the rotational moment about the z-axis is controlled and the motion state of the vehicle is controlled. Of course, the control differential 7 and the transmission control means 1
Needless to say, 4 is used.

Referring to FIG. 14, control unit 1
The process of estimating the vehicle motion inside 6 will be described. When the control unit 16 detects the rotational acceleration ω _z of the six-degree-of-freedom motion sensor 15 around the z-axis (when turning starts), the control unit 16 resets the integration circuit of the six-degree-of-freedom motion sensor 15 and starts the detection at the same time. 6 DOF motion sensor 15
From the translation speed v _{x in} the x-axis direction and the translation speed v _{y in the} y-axis direction, the vehicle center-of-gravity skid angle β = arctan
(V _x / v _y ) is calculated. Furthermore the rotational speed omega _z of the z-axis around the steering angle inputted through the steering 8 by the driver (which is detected from the steering angle control unit 11 which also serves as a steering angle sensor) and subjected to a slip angle of each wheel To detect. On the other hand, the rotation angle around the x-axis (roll angle) and the rotation angle around the y-axis (pitch angle) are detected by the six-degree-of-freedom motion sensor 15 to detect a change in the attitude of the vehicle, and the load applied to each wheel is determined. To detect. Further, each wheel suspension mechanism 6a, 6
b, 6c, 6d stroke sensors 61a, 61b, 6
6-DOF motion sensor 15 based on information from 1c and 61d
The vehicle posture change information detected in step is corrected. A change in the alignment such as a change in the camber angle and a change in the toe angle is detected from the change in the posture of the vehicle body thus obtained and the design data of the suspension link mechanism. At the same time, the wheel speed of each wheel is detected by a wheel speed sensor and is compared with the vehicle speed detected by the six-degree-of-freedom motion sensor 15 to detect the slip ratio of each wheel. The driving force and the brake estimated from the driver's throttle opening detected by the throttle control unit 12 and the gear position detected by the transmission control unit 14 together with the sideslip angle, load, alignment change, and slip ratio of each wheel described above. Information on the braking force estimated from the driver's brake line pressure detected by the hydraulic control unit 13, the maximum differential limiting torque of the rear wheels detected from the control differential 7, and various other information such as tire non-linearity. Calculate the cornering force for each wheel. Then, a motion equation having six degrees of freedom is solved by using the obtained cornering force, braking force, and driving force of each wheel to estimate the vehicle motion. In addition, in the same manner as above, using the cornering force, braking force, and driving force of each wheel, six degrees of freedom in which the motion characteristics of the reference vehicle as the control target stored in the control unit 16 in advance are described. Solve the equation of motion and set it as the control target for vehicle motion.

FIG. 15 shows that the vehicle is turning at the limit speed.
The control process of the control unit 16 when the vehicle motion is represented by the rotation speed around the z-axis and neutral steer (a vehicle whose motion state is determined only by the steering angle and the speed) is selected as the reference vehicle is shown. The rotation speed ω about the z-axis of the reference vehicle estimated by the procedure as shown in FIG.
_z0 and is compared with the rotational speed omega _z of the z-axis around the vehicle. now,
If ω _z −ω _z0 > ξ (ξ is an arbitrary constant that satisfies ξ> 0), the control unit 16 determines that the vehicle has over-steered compared to the reference vehicle, and provides this information to the driver. It may be presented and called for attention. The control unit 16 issues a correction command to the steering angle control unit 11 to set the steering angle δ to δ−Δδ. If this at a reduced rotational speed omega _z of the z-axis around the, omega _z continue to correction so as to follow the omega _z0. However, the steering angle to be reduced rotational speed omega _z also z-axis around reduces .DELTA..delta, the throttle control unit 12 and the brake pressure control unit 13 while decreasing the steering angle, as in the steering angle [delta], the throttle The opening θ and the brake line pressure ζ are reduced, and the transmission control unit 14 and the control differential 7 are used to correct the braking force and the driving force of the right and left rear wheels so as to decrease appropriately, thereby increasing the load on the front wheels. At the same time, the cornering force of the rear wheel is increased, and the rotational moment about the z-axis is relatively reduced. Further, the steering angle is cut (counter-steering) until the turning direction is opposite to that of the turning direction, and correction is made so that a moment opposite to the current rotating direction is positively applied around the z-axis. In this way, the ω _z is corrected control so as to follow the ω _z0. However, if you really ω _z is not reduced, the cuts in the counter-steering direction to further full lock the steering angle in order to avoid danger, while maintaining the brake hydraulic pressure to the relationship between the front wheel> rear wheel, the center of gravity of the vehicle slip angle β is π / The vehicle may be stopped so that the vehicle approaches the second position.

Next, when ω _z0 −ω _z <ξ ′ (ξ ′ is an arbitrary constant satisfying _{を 満 た す} ′> 0), the control unit 16
May determine that an understeer has occurred in the vehicle as compared to the reference vehicle, present this information to the driver, and warn the driver. The control unit 16 issues a correction command to the steering angle control unit 11 to set the steering angle δ to δ + Δδ. If This increases the rotational speed omega _z of the z-axis around, omega _z
Continue the correction so as to follow ω _z0 . However, if the rotational speed omega _z of the z-axis around even when the steering angle is increased Δδ is increased is regarded as the front wheel cornering force has reached the limit, and throttle control unit 12, a brake pressure control unit 13, The transmission control unit 14 and the control differential 7 are used to correct the braking force and the driving force of the right and left rear wheels so as to increase appropriately, thereby increasing the load on the front wheels, increasing the cornering force of the front wheels, and increasing the front wheel cornering force. reducing the cornering force increases the rotational moment of relative z-axis around, omega _z can be corrected so as to follow the omega _z0. If ω _z still does not increase, it is considered completely uncontrollable, the throttle opening is fully closed, the gear position is lowered, and while applying engine braking, brake oil pressure is applied until the rear wheels idle, and Control similar to a so-called spin turn may be performed in which the cornering force of the wheel is set to zero and the rotational moment about the z-axis is increased at a stretch. Here, when the rotation speed around the z-axis suddenly increases, the above-described control during oversteer may be performed.

In general, the steering characteristics of a vehicle are often designed to be understeered. Therefore, the occurrence of oversteer as described above occurs when the road surface is a road having an extremely low friction coefficient such as a frozen road and when the driver intentionally applies a large braking / driving force to each wheel (particularly, the rear wheels). To induce oversteer. In the former case, the control shown in FIG. 15 may be used. However, in the latter case, it is considered that the skid angle of the center of gravity of the vehicle is positively increased and the vehicle is going to perform a so-called drift running in which the vehicle turns while the counter steer is applied. In such a case, the control unit 16 determines the rotational speed ω about the z-axis.
_It is desirable to control the vehicle center-of-gravity skid angle β in accordance with the driver's operation at the same time as controlling _z, that is, to change the kinetic characteristics of the reference vehicle to be controlled in accordance with the driver's operation without giving the driver a sense of incongruity. .

FIG. 16 shows an example of a driver's operation when the side slip angle of the center of gravity is actively increased in a general vehicle, and FIG. now,
At the time when oversteer is detected, the side slip angle of the vehicle center of gravity is β0, the steering angle is δ0, the throttle opening is θ0, and the brake line pressure is ζ0. In FIG. 16, the steering angle δ at the time of occurrence of oversteer is accurately reduced, and the throttle opening θ is increased correspondingly. That is,
The steering angle is reduced until it is opposite to the turning direction (counter steering), so that a moment opposite to the current rotation direction is positively applied around the z-axis, and at the same time, the rear wheel driving force is increased. By performing the opposing operations of decreasing the cornering force of the rear wheel and increasing the rotational moment around the z-axis relatively, the balance control is performed so that the rotational moment around the z-axis becomes zero. It is. On the other hand, in FIG. 17, the brake is depressed due to unexpected oversteer, and z
As a result, the rotational moment about the axis is increased, and the vehicle center-of-gravity skid angle β is increased. Furthermore, the operation timing of the steering angle δ as a correction for the vehicle center-of-gravity sideslip angle β is delayed, causing a so-called Dutch roll phenomenon. As is apparent from a comparison between FIG. 16 and FIG. 17, by detecting the vehicle center-of-gravity skid β, the steering angle δ, the throttle opening θ, and the brake line pressure の during oversteer, the driver's Can estimate the will.

FIG. 18 shows the operation of the control unit 16 when oversteer occurs when the throttle opening θ is evaluated as the driver's will. First, the throttle opening θ0 at the time of occurrence of oversteer is detected, and
Let it be 1. After a lapse of time Δt, the throttle opening θ2
And the translation speed v _{x in the} x-axis direction, the rotation speed ω _z about the z-axis,
The vehicle center-of-gravity point sideslip angle β1 is detected. Where dθ / dt
If dθ / dt> 0, it is considered that the driver is about to induce oversteer, and the reference vehicle motion characteristic is changed to the pseudo oversteer characteristic according to the driver's intention. Specifically, the accepted rotation speed ω _z around the z-axis is increased, and the vehicle center-of-gravity skid angle β is set to β
1 is multiplied by a value obtained by multiplying the time change dθ / dt of the throttle opening by an appropriate proportional constant K, and β = β1 +
For example, the set value is changed to K · dθ / dt. Here, the control unit 16 sets the reference steering angle control curve f (θ, v _x) with the throttle opening θ, the translation speed v _{x in the} x-axis direction, the rotation speed ω _z about the z-axis, and the vehicle center-of-gravity point side slip angle β as variables. ,
ω _z , β) is determined (for the sake of simplicity, the right curve is targeted here and only v _x is a parameter). In the reference steering angle control curve f (θ, v _x , ω _z , β), the throttle opening at which the steering angle becomes full lock is θmax.
And This throttle opening is the maximum value that can avoid spin in the steering angle control including the counter steering. When the driver opens the throttle beyond this value, the control unit 16 corrects to θ2 = θmax and issues a control command to the engine 1 via the throttle control unit 12. θ2 <θ
When the max, the steering angle _{δ = f (θ2, v x} , ω z,
β). Hereinafter make this repetition, so as to follow the intention of the driver, updates the norm steering angle control curve, continues to control so as to follow the vehicle motion thereto, the rotational speed omega _z of the z-axis around becomes zero At this point, it is considered that the vehicle has escaped from the corner, and the correction control is completed.

FIG. 18 shows an example in which the driver intends to perform drift travel. However, in other cases, various types of maneuvering amounts (steering angle, throttle opening, brake oil pressure, etc.) attributable to the driver's will can be used. ) Is detected, the driver's will is inferred, the reference motion characteristic is updated so as to follow the driver's will, and control is performed so that the vehicle motion follows the reference motion characteristic.

When such control is performed, the control unit 16 displays the correction control values of the steering angle, the brake pressure, and the throttle opening to the driver in real time, so that the operation of the driver and the actual operation can be performed. A difference in the operation amount for causing the vehicle to move or a difference in the timing may be indicated. When it is determined that the difference between the operation amounts and the difference between the timings is small, the driver may arbitrarily select whether to perform control or not.

In the above-described embodiment of the present invention, a vehicle with front two wheels steering front engine and rear drive has been described. However, a method of detecting vehicle motion with six degrees of freedom and a cornering force of each wheel are controlled. It goes without saying that the control by controlling the driving force and the positive control of the steering angle in the direction opposite to the normal turning can be applied to all vehicles such as electric vehicles.

[0060]

According to the present invention, when the vehicle exceeds the motion limit such as spin, drift, understeer, etc., it can be returned to the limit by performing the same control as a skilled driver, thereby avoiding danger. There is a connecting effect.

[Brief description of the drawings]

FIG. 1 is an overall control configuration diagram showing an embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a steering angle control unit.

FIG. 3 is a diagram showing a configuration of a throttle control unit.

FIG. 4 is a diagram showing a structure of a differential mechanism of a throttle control unit.

FIG. 5 is a diagram showing a configuration of a brake hydraulic control unit.

FIG. 6 is a diagram showing a configuration of a 6-DOF motion sensor.

FIG. 7 is a diagram showing an arrangement of an acceleration sensor.

FIG. 8 is a diagram illustrating a trajectory of a vehicle that has entered a spin state.

FIG. 9 is a diagram showing a vehicle trajectory using counter steer.

FIG. 10 is a diagram showing a two-dimensional dynamic balance of the vehicle when there is no skidding of the center of gravity of the vehicle.

FIG. 11 is a diagram showing a two-dimensional dynamic balance of the vehicle when there is a skid of the vehicle center of gravity.

FIG. 12 is a diagram showing a two-dimensional dynamic balance of the vehicle when counter-steering is used when there is a vehicle center-of-gravity skidding.

FIG. 13 is a diagram showing a method for controlling a cornering force in the embodiment of the present invention.

FIG. 14 is a diagram showing a process of predicting a vehicle motion according to the embodiment of the present invention.

FIG. 15 is a diagram showing a control process in the embodiment of the present invention.

FIG. 16 is a diagram showing a driver's operation when the side slip angle of the center of gravity is actively increased in a general vehicle.

FIG. 17 is a diagram showing a driver's operation when the side slip angle of the center of gravity is not actively increased in a general vehicle, and is a diagram showing the driver's operation during oversteer.

FIG. 18 is a diagram showing a process of modifying reference vehicle characteristics.

[Explanation of symbols]

Reference Signs List 1 engine 2a right front wheel 2b left front wheel 2c right rear wheel 2d left rear wheel 3a right front wheel speed sensor 3b left front wheel speed sensor 3c right rear wheel speed sensor 3d left rear wheel speed Sensor 4a: right front wheel brake 4b: left front wheel brake 4c: right rear wheel brake 4d: left rear wheel brake 5: steering mechanism 6a: right front wheel suspension mechanism 6b: left front wheel suspension mechanism 6c: right rear wheel suspension mechanism 6d: left rear Wheel suspension mechanism 7 Control differential 8 Steering 9 Accelerator pedal 10 Brake petal 11 Steering angle control unit 111 Actual steering angle encoder 112 Gear box 113 Steer motor 114 Wet multi-plate clutch 115 Steer feel correction motor 116: gear box 117: steering angle encoder 118: actual steering Control section 1181 Power transistor 1182 Actual steering current detection sensor 119 Steer feel correction section 1191 Power transistor 1192 Steer feel current detection sensor 12 Throttle control section 120 Wire 121 Throttle valve 122 Differential mechanism 123 Throttle position Sensor 124 Servo motor 13 Brake oil pressure control unit 131 Link mechanism 132 Servo motor 133 Master cylinder 134 Master oil pressure sensor 135 Brake oil pressure control valve 136 Each wheel oil pressure sensor 14 Mission control unit 15 6 degrees of freedom Motion sensor 16 ... Control unit

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-63-315374 (JP, A) JP-A-2-200031 (JP, A) JP-A-3-1255061 (JP, A) JP-A-1- 270635 (JP, A) JP-A-63-306934 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B60K 41/28

Claims (8)

(57) [Claims] A means for detecting a steering angle, a means for detecting a brake oil pressure, a means for detecting a throttle opening,
Means for detecting a vehicle movement state, reference vehicle movement characteristic state storage means for storing a reference vehicle movement characteristic, a steering angle detected by the steering angle detection means, and a brake oil pressure detected by the brake oil pressure detection means. A vehicle movement state prediction means for predicting a next vehicle movement state based on a throttle opening detected by the throttle opening degree detection means and a vehicle movement state detected by the vehicle movement state detection means; The steering angle obtained, the brake oil pressure detected by the brake oil pressure detection means, the throttle opening detected by the throttle opening detection means, the vehicle motion state detected by the vehicle motion state detection means, and the reference vehicle motion characteristic state storage means. Reference vehicle motion state prediction means for predicting the stored reference vehicle motion characteristics and the next reference vehicle motion state,
Vehicle to chromatic and control means of the steering angle, the control means of the brake hydraulic pressure, and control means of the throttle opening, the control means of the gear position, the control means of the maximum differential limiting torque of the differential of the drive wheel, the , Wherein the reference vehicle motion characteristic state storage means stores
Vehicle motion characteristics are defined as various types of steering
Angle, various brake oil pressure, various throttle opening,
A response of various vehicle motion states of a reference vehicle, in which the vehicle motion state predicted by the vehicle motion state prediction means is expected to significantly deviate from the reference vehicle motion state predicted by the reference vehicle motion state prediction means. In addition to steering, braking and throttle operation of the driver, the steering angle control means and the steering angle control means reduce the deviation between the reference vehicle movement state and the vehicle movement state detected by the vehicle movement state detection means. One or more of the steering angle, brake oil pressure, throttle opening, gear position, and maximum differential limiting torque of the driving wheel differential device by the brake hydraulic pressure control means, the throttle opening control means, and the gear position control means. Multiple
A vehicle motion characteristic correction device characterized in that it is configured to control a person or all persons. In the vehicle motion characteristic correction apparatus according to claim 2 according to claim 1, wherein the vehicle and the motion state vehicle motion state detected by the detecting means, the wheel speeds, the vehicle front-rear direction of the jerk, the vehicle longitudinal acceleration, Vehicle longitudinal speed, vehicle lateral jerk, vehicle lateral acceleration, vehicle lateral speed, vehicle vertical jerk, vehicle vertical acceleration,
Vehicle vertical speed, vehicle roll angle jerk, vehicle roll angular acceleration, vehicle roll angular speed, vehicle roll angle, vehicle
Pitch angle jerk, vehicle pitch angle acceleration, the vehicle pitch angular velocity, vehicle pitch angle, the vehicle yaw angle jerk, vehicle yaw angular acceleration, vehicle yaw rate, 1 person Moshiku of the vehicle yaw angle
Is a vehicle motion characteristic correction apparatus characterized by two or more persons or all persons. 3. The vehicle dynamics characteristic correcting device according to claim 1, wherein said brake hydraulic pressure control means comprises:
The brake oil pressure of the wheel is locked independently from the wheel unlocked state.
A vehicle dynamics characteristic correcting device for controlling up to a parking state . 4. The vehicle motion characteristic correcting device according to claim 1, wherein said vehicle motion state predicting means.
Predicted vehicle motion state is the reference vehicle motion state prediction
Significant deviation is expected from the reference vehicle motion state predicted by the means
Display the deviation to the driver to warn the driver
Vehicle motion characteristic correction device being characterized in that the. 5. The vehicle dynamics characteristic correcting device according to claim 1, wherein the driving operation of the driver and the vehicle
Display difference of control operation of motion characteristic correction device to driver
Vehicle motion characteristic correction device being characterized in that the like. 6. The vehicle dynamic characteristic correction device according to claim 1 , wherein the control is arbitrarily performed by a driver.
A vehicle dynamics characteristic correction device characterized in that the vehicle dynamics characteristic can be selected . 7. A means for detecting a steering angle, and a brake oil pressure
Means for detecting the throttle opening, means for detecting the throttle opening,
Means for detecting the vehicle motion state and a vehicle motion characteristic
Reference vehicle motion characteristic state storage means for storing
The brake oil pressure detected by the brake oil pressure detecting means
Throttle opening detected by throttle opening detection means and the front
The vehicle motion state detected by the vehicle motion state detection means and the
The reference vehicle stored in the reference vehicle motion characteristic state storage means.
Motion characteristics and next norms. Norms for predicting vehicle motion status.
Vehicle motion state predicting means, steering angle control means,
Control means for the hydraulic pressure, control means for the throttle opening,
Maximum difference between positioning control means and drive wheel differential
Norms Te vehicle odor and a control means of the dynamic limit torque, the norms vehicle motion characteristic state storage means stores
Vehicle motion characteristics are defined as various types of steering
Angle, various brake oil pressure, various throttle opening,
Responses of various vehicle motion states of the reference vehicle,
The vehicle motion state detected by the vehicle motion state detection means is
Reference vehicle motion state predicted by the reference vehicle motion state prediction means
If there is a significant deviation from the
The deviation from the vehicle motion state detected by the vehicle motion state detection means.
In order to reduce the difference, steering, braking,
In addition to the throttle operation, the steering angle control means and the brake
Hydraulic pressure control means, throttle opening control means and gear position
Steering angle, brake oil pressure, slot
Opening, gear position or drive wheel differential
One or more persons with the maximum differential torque limit
Or a vehicle dynamics characteristic correcting device configured to control everyone . 8. The vehicle motion characteristic correction device according to claim 7, wherein
The vehicle motion detected by the vehicle motion state detecting means.
The states are each wheel speed, jerk in the vehicle front-rear direction, and vehicle front.
Rearward acceleration, vehicle longitudinal speed, vehicle lateral direction
Jerk, vehicle lateral acceleration, vehicle lateral speed
Degree, vertical jerk, vehicle vertical acceleration,
Vehicle vertical speed, vehicle roll angle jerk, vehicle low
Angle acceleration, vehicle roll angular velocity, vehicle roll angle, vehicle
Pitch angle jerk, vehicle pitch angular acceleration, vehicle pitch angular velocity
Degree, vehicle pitch angle, vehicle yaw jerk, vehicle yaw angle
One of speed, vehicle yaw speed, vehicle yaw angle
Is a vehicle motion characteristic correction apparatus characterized by two or more persons or all persons .