JPH042558A - Traction steering gear - Google Patents

Abstract

PURPOSE:To prevent lowering of riding comfort caused by frequent increase/ decrease of driving force by offsetting the detection value of at least one of a steering angle and the actual yaw rate related quantity toward phi by a quantity corresponding to its drift quantity, while ignoring the other one of small fluctuation. CONSTITUTION:A traction steering gear is provided with a traction steering means 4 for controlling the driving force of a wheel in such a way as to minimize the difference between the target yaw rate related quantity, determined on the basis of the body speed and a steering angle detected by a body speed detecting means 1 and a steering angle detecting means 2, and the actual yaw rate related quantity detected by an actual yaw rate related quantity detecting means 3. This traction steering gear is further provided with a drift detecting means 5 for detecting the drift quantity of at least one of the steering angle and the actual yaw rate related quantity in the rectilinear state of a vehicle, and an offsetting means 6 for offsetting at least one detected value toward phiby the quantity corresponding to the detected drift quantity.

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF INDUSTRIAL APPLICATION The present invention relates to a traction steer system for an automobile, and particularly to prevention of deterioration in riding comfort due to fluctuations in target values and actual measured values.

BACKGROUND OF THE INVENTION Traction steer devices that control the traveling direction of a vehicle by controlling wheel drive forces are already known. For example, Japanese Patent Application Laid-Open No. 60-248466 discloses a traction steer device that prevents drift and spin from occurring when braking is applied during a turn. During braking, the cornering force decreases due to the occurrence of slip in the wheels, so when turning when the product of the steering angle and the vehicle speed is large, the sideslip of the wheels increases, which may cause drift or spin. The traction steer device sets a target yaw rate based on the vehicle speed steering angle and actual yaw rate at the start of braking, and the vehicle body speed and steering angle during braking, and adjusts the front and rear wheels so that the actual yaw rate is equal to the target yaw rate. This system independently controls the brake fluid pressure for the wheels.

In addition, Japanese Patent Application Laid-Open No. 63-203456 discloses that during a turn in a non-braking state, the vehicle is decelerated while avoiding forward load transfer as much as possible, suppressing sideways slip of the rear wheels and preventing the occurrence of spin. A traction steer device is disclosed. This device applies rear wheel brakes to decelerate the vehicle with a relatively small forward load shift when the actual yaw rate or lateral acceleration exceeds a set value while turning in a non-braking state. This prevents spin from occurring by reducing sideslip of the rear wheels, and in a desirable mode where only the rear wheels on the outside of the turn are braked, it generates a yawing moment to the outside of the turn to further ensure the occurrence of spin. This is to prevent

Problems to be Solved by the Invention In order to perform traction steering, actual yaw rate related quantities (includes not only the yaw rate itself, but also all quantities that are closely related to the yaw rate, such as lateral acceleration, and indirectly represent the yaw rate) and steering It is necessary to detect corners, but these detected values usually include fluctuations due to road noise, equipment play, etc. If the steering angle includes wander, the target yaw rate that is set based on it will fluctuate, resulting in unnecessary wheel drive force control, and the amount of control will fluctuate frequently, causing vibrations in the vehicle body. This causes the ride to become uncomfortable. The same applies when the actual yaw rate related amount includes wander.

The present invention has been made with the object of providing a traction steer device that can reduce the reduction in ride comfort caused by fluctuations in the actual yaw rate-related quantities and steering angle.

Means for Solving the Problems As shown in FIG. The actual yaw rate related amount detection means 3 detects the related amount, the target yaw rate related amount determined based on the vehicle speed and steering angle detected by the vehicle speed detection means and the steering angle detection means, and the actual yaw rate related amount detection means. A traction steer device that controls the traveling direction of a vehicle, including a traction steer means 4 that controls the driving force of the wheels so that the difference from the detected actual yaw rate related quantity becomes small,
Wobble detection means 5 detects the wobble amount of at least one of the steering angle and the actual yaw rate related quantity when the vehicle is traveling straight; This can be solved by providing an offset means 6 for offsetting toward 0.

The above-mentioned "amount according to the amount of fluctuation" may be the maximum value of the amount of fluctuation, or may be a value obtained by averaging such as smoothing processing.

Alternatively, any one of the off-moment 1 to amount determined in a plurality of stages may be a value selected based on the detected amount of wobbling. In any case, the offset amount is set according to the detected amount of wobbling, but it cannot be changed along with the wobbling of the steering angle and actual yaw rate-related amounts, and once it is set, it remains unchanged for at least a certain period of time. It is kept at a constant value.

Effect As described above, if the detected value of at least one of the steering angle and actual yaw rate related quantities is offset toward 0 by an amount corresponding to the amount of wobbling of at least one of them, small fluctuations in the other will be ignored. Therefore, it is avoided that the wheel driving force is frequently increased or decreased and the riding comfort is deteriorated as in the case where the vehicle is not ignored.

Effects of the Invention As described above, according to the present invention, it is possible to reduce the reduction in riding comfort caused by frequent unnecessary increases and decreases in wheel driving force.

Moreover, since the magnitude of the fluctuation to be ignored is determined based on the actual wobbling detected by the wobbling detection means, the sensitivity of the traction steer device does not become overly sensitive or excessively reduced. Although it is possible to reduce ride comfort by always offsetting the steering angle and actual yaw rate by a certain amount, the fluctuation of the steering angle and actual yaw rate varies depending on the vehicle and driver as well as the condition of the road surface during driving. If the offset amount is always set to a constant value, it is inevitable that the offset amount will be too large or too small. If the offset amount is too large, the sensitivity of the traction steer device becomes poor and a sufficient traction steer effect cannot be obtained, and if it is too small, unnecessary increases and decreases in wheel driving force cannot be sufficiently avoided.

In contrast, in the present invention, the offset amount is set based on the actual amount of wobbling, so the sensitivity of the traction steer device can always be maintained at an appropriate level.

EXAMPLE Hereinafter, an example of the present invention will be described in detail based on the drawings.

In FIG. 2, the brake pedal lO is connected to a mask cylinder 14 via a booster 12. The mask cylinder 14 is a tandem cylinder with two pressurized chambers,
The hydraulic pressure generated in one pressurizing chamber is transmitted to the brake 20 of the left front wheel 18 and the brake 24 of the right front wheel 22 through the main liquid passage 16, and the hydraulic pressure generated in the other pressurizing chamber is transmitted to the main liquid passage 26.
The signal is transmitted to the brake 30 of the left rear wheel 28 and the brake 34 of the right rear wheel 32. A provisioning/high-pass valve 36 is provided in the middle of the main liquid passage 16.26, and when the liquid pressure in the main liquid passage 16 increases normally, the liquid pressure in the main liquid passage 26 is reduced, and the main liquid If the hydraulic pressure in the passage 16 does not rise normally, the hydraulic pressure in the main liquid passage 26 is not reduced.

Proportioning of main liquid passage 26/bypass valve 3
A cylinder cut valve 40, which is an electromagnetic opening/closing valve for mask cylinder cutting, is provided downstream of the mask cylinder cut valve 6, and a hydraulic control valve 40, which is an electromagnetic directional switching valve with three positions, is provided in each of the two bifurcated portions of the main liquid passage 26. Valves 42,44 are provided. Hydraulic control valves 42.44 are connected to reservoir 48 by return passages 46, and hydraulic control valves 42.44
A check valve 54. is provided in the bypass passage 50.52 that bypasses the
56 are provided.

Cylinder cut valve 40 and hydraulic pressure control valve 42 in main liquid passage 26
．． An accumulator 60 is connected to the portion between the accumulator 44 and the accumulator cut valve 62 . Brake fluid pumped up from the reservoir 48 by the pump 64 is stored in this accumulator 60 at high pressure, and when the accumulator cut valve 62 is opened, the hydraulic pressure control valve 42
．． 44 to the brake 30.34. 66 is a relief valve.

These cylinder cant valves 40. Hydraulic pressure control valve 42°44,
Return passage 46. Check valves 54, 56. Accumulator 60
．． Accumulator cut valve 62. Pump 64. The relief valve 66 and the like constitute an actuator 68 for performing anti-skid control, and the traction steer device of this embodiment uses this actuator 68 to control the direction of movement of the vehicle.

The front wheels 18,22 are steered wheels and are steered by a steering device 76 consisting of a steering wheel 70, a steering gearbox 72, a steering link 74, etc.

The steering angle θ and the steering torque τ of the steering wheel 70 are detected by the steering angle sensor 80 and the steering torque sensor 81, respectively, the depression of the brake pedal 10 is detected by the pedal switch 82, and each wheel 18, 22 .
The rotational speed of 28.32 is the rotation sensor 84 and 86 respectively.
, 88, 90, and the yaw rate of the vehicle body 92 is detected by a yaw rate sensor 94 fixed to the vehicle body 92. These output signals are provided to main controller 96.

The main control device 96 is mainly a computer, and has an input interface 100. Output interface 10
2. CPU104. It includes a ROM 106 and a RAM 108. The ROM 106 stores control programs represented by flowcharts shown in FIGS. 3, 4, 5, 6, and 7 and a road surface μ related quantity table 109.

There is a relationship shown in FIG. 8 between the friction coefficient μ of the road surface and the road surface μ related amount M. In addition, vehicle speed ■ and steering torque τ
There is also a certain relationship between the coefficient of friction μ and the relationship determined through experiments and the relationship shown in FIG. A road surface μ related quantity table 109 is created, and the RO
It is stored in M106. On the other hand, RAM 1
0B is provided with various memories including a vehicle speed memory 110 shown in FIG.

Hereinafter, the operation of the present traction steer device will be explained with reference to a flowchart.

Traction steer is executed according to the main routine shown in FIG. In step Sl (hereinafter simply referred to as 81; the same applies to other steps), initial settings are performed, the traction steer flag FF, the previous right control flag XRR, the previous force control flag XRL, etc. are turned OFF, and the update time counter RC, left and right pressure increase remaining time counter TACC, L, TACCR, pressure reduction remaining time counter TB
D Left and right opposite side decompression remaining time counters TLD, TRD,
Yaw rate difference memory 138. This time brake fluid pressure memory 1
40 etc. are cleared, and the cylinder cut valve 40
is opened, the accumulator cut valve 62 is closed, the left and right hydraulic pressure control valves 42, 44 are brought into a pressure increasing state, and the pump 64 is brought into a stopped state.

Subsequently, in S2, the steering angle θ and the actual yaw rate Y,
The offset amount of l is determined, the brake fluid pressure is determined in S3, the start/stop of brake fluid pressure control is performed in S4, and the brake fluid pressure is controlled in S5.

The offset amount in S2 is determined by executing a program shown in the flowchart of FIG. First, Sl.
At 1, the vehicle speed 2 is calculated based on pulse signals from the rotation sensors 84, 86°88.90. for example,
The vehicle speed ■ is calculated from the pulse signal representing the second largest speed among the pulse signals from each rotation sensor, and is stored in the vehicle speed memory 110. Next, in steps 313 to 18, it is determined whether the conditions for offset determination are met. The offset amount is determined while traction steer control is not being performed and the vehicle is traveling straight. Specifically, (1) traction steer is not being executed, (2) the vehicle speed ■ is above a certain value, and (3) the rotational speed difference between the left and right front wheels 18.22 is below a certain value. , (4) the steering angle θ is below a certain value, and (5)
This is carried out only while the condition that the amount of change in the steering angle θ is equal to or less than a certain value is met.

While the traction steer is being executed, the actual yaw rate Y, 1, etc. fluctuates, so it is not suitable for determining the offset amount, and it is determined whether the traction steer is being executed depending on whether the traction steer flag FF is turned on in S12. Ru. In addition, if there is a substantial difference in the rotational speed of the left and right front wheels 18.22 or if the steering wheel 70 is not in a substantially neutral position, the vehicle is not in a straight-ahead state, so in S14 and 315 and S16 and S17, It is determined whether the absolute value of the difference between the speeds VWFL and VWFR of the left and right front wheels and the absolute value of the steering angle θ are each larger than a certain value KK2. When reading the steering angle θ in S16, the value stored in the current steering angle memory 112 is transferred to the previous steering angle memory 113, and the newly read value of the steering angle θ is stored in the current steering angle memory 112. Si2 judgment is based on the left and right front wheels 1 while the vehicle speed ■ is small.
8,22 rotational speed V. This is done to prevent S'14 and S'15 from being executed during that time since FL and VWFI+ cannot be detected accurately. Also, the current steering angle θ of 31B
The determination as to whether the absolute value of the difference between (1) and the previous steering angle θ(t-1) is larger than a constant value of 3 is made when the vehicle is turned This is done to prevent the offset amount from being determined in the shaded area when transitioning to a straight-ahead state or from a straight-ahead state to a turning state.

If even one of the conditions (1) to (5) above is not satisfied, the execution after 518a is skipped, and in S32 the update time counter RC and the offset amount - time memory 1 are
22, 124, 126, and 128 are cleared, and the execution of one offset amount determination routine ends. If all the conditions are satisfied, the actual yaw ray 1-YR is read from the yaw rate sensor 94 at 518a. After being stored in the actual yaw rate memory 136, the offset amount is determined in step S19.

Offset amount determination is performed in S23 to S31 every update time RC, while the above conditions are satisfied, and when the end of update time RC is detected in 319 and S20, in S22, the steering angular force offset amount until then is determined. Memory 114. Steering angle cloth offset amount memory 116. Each offset amount stored in the yaw rate left offset amount memory 118 and the yaw rate 1-right offset amount memory 120 is changed to the newly determined offset amount.

In S23, the steering wheel 7 is
It is determined whether the 0 is turned to the right or to the left, and based on each determination result, at 324 to 27 and 328 to 31, the offset amount θ0FFL+ YOFFL+ θ of the left and right steering angles θ and the actual yaw rate YR, respectively.
0FFR, YOFFI+ are determined. Above (1) to (
While the condition 5) is satisfied, the maximum detected values of the steering angle θ and the actual yaw ray l-Y are offset amount-time memories 122, 124, 1 as shown in the lower part of FIG.
26 and 128. When the value of these hour memories is 320 and it is determined that the update time RC has passed, the corresponding offset amount memory 1141
16. Stored at 118 and 120. The offset amount is updated every update time RC in this way.
This is because the appropriate offset amount varies depending on the vehicle and driver, and also varies depending on the road surface condition.

The brake fluid pressure of S3 is determined by the flowchart 1 of the 5th leap.
It is carried out according to the following. First, in S41, it is determined whether the steering angle θ currently stored in the steering angle memory 112 is turning left or turning right, based on the sign or negative of the steering angle θ currently stored in the steering angle memory 112, and in S42. S
43 or 344.45, the steering angle θ and the actual yaw rate Y7 are each offset amount θ determined in S2 above. 4. L.

YOFFL or θ. F□+ "0FFR is offset toward O. If the steering angle θ and the actual yaw rate YR are larger than each offset amount, the steering angle θ and the actual yaw rate YR are simply reduced by the offset amount. If they are smaller than the offset amount, the steering angle θ and the actual yaw rate YR are Yolei l-Y.

is taken to be O.

Next, in S46, the steering torque τ is read from the steering torque sensor 81 and stored in the steering torque memory 130. Then, in S47, the vehicle speed memo IJ 11
The road surface μ is calculated from the road surface μ related quantity table 109 using the vehicle body speed V of 0 and the steering torque τ of the steering torque memory 130.
A related quantity M is determined and stored in the road surface μ related quantity memory 132. The offset amounts of the steering angle θ and the actual yaw ray h Y * are determined while driving straight, whereas the road surface μ related amount M is determined at all times, and the value during turning is actually used for brake fluid pressure control. That's why. Next, S4
In step 8, the target yaw rate Y is calculated from the vehicle speed ■, the steering angle θ, the road surface μ-related amount M, and the following formula (%). Stored. In this example,
If the vehicle speed ■ and the steering angle θ are the same, the smaller the friction coefficient μ of the road surface (in this case, the smaller the road surface μ related amount M), the smaller the target yaw rate Y0 is set.

After setting the target yaw rate Ya, the yaw rate difference DV is calculated using the following equation Dy-1Ya1-YR and stored in the yaw rate difference memory 138 in S49. Subsequently, in S50, the contents of the current brake fluid pressure memory 140 are transferred to the previous brake fluid pressure memory 1.42, and in S51, the current brake fluid pressure P(t) is determined by the following formula %, where G is $11? It is calculated based on the wholesale gain and stored in the current brake fluid pressure memory 140.

This completes the determination of the brake fluid pressure, and then start/stop control of the brake fluid pressure is performed according to the flowchart in FIG.

First, in S60, it is determined whether or not the brake pedal 10 has been depressed based on the output signal of the pedal switch 82. If the brake pedal 10 has not been depressed, the yaw rate difference DV is equal to the reference value in S61. It is determined whether the value is greater than or not. It is determined whether there is a difference of more than a certain value between the target yaw rate Y1 and the actual yaw ray I-Y, and if so, the end processing remaining time counter EC is cleared in S62.
In S63, the traction steer flag FF is set to O in order to start the traction steer by the action of the brake.
In step S64, the cylinder cut valve 40 is closed, the accumulator cut valve 62 is opened, and the pump 64 is closed.
operation will begin.

On the other hand, if there is no difference greater than a certain level between the target yaw rate Y1 and the actual yaw rate YR, it is determined in S65 whether traction steer flag FF is ON or not, and whether or not traction steer is currently being executed. If it is, after the end processing waiting time KTE has elapsed by executing S66 to S69, 370. The termination process of S71 is performed, and if it is not currently being executed, the termination process of S70.71 is simply performed.

Next, brake fluid pressure control for traction steering is performed according to the flowchart in FIG.

First, in S81, it is determined whether brake fluid pressure control should be performed depending on whether the traction steer flag FF is turned on or not. If control is not necessary, the end processing of 5117 and 5108 is performed. At 5117, both the left and right brake hydraulic pressure control valves 42 and 44 are set to the pressure increasing state, and the previous cloth control flag XRR and the previous left control flag XRL are turned OFF, and at 8108, the left and right pressure increase remaining time counter TACCR is set. , TACCL decompression remaining time counter TBD and left and right opposite side decompression remaining time counters TRD and TLD are cleared.

On the other hand, if the traction steer flag F is ON at the time of determination in S81, it is determined in S82 whether the count value of the end processing remaining time counter EC is O, and if it is 0, the count value is increased according to the determination result in S83. Pressure, depressurization, or holding control is executed. This time brake fluid pressure P (t
) is higher than the previous brake fluid pressure P (t-1), 384
Pressure increase control is performed at ~104, and if it is low, 8111
-116, pressure reduction control is performed, and if the current brake fluid pressure PD) and the previous brake fluid pressure P(t-1) are equal, holding control is performed at 5107.108.

While the difference D between the actual yaw rate YR and the target yaw rate Yr is increasing, the current brake fluid pressure P(t) is set to a higher value than the previous brake fluid pressure P(tl) in S50 and S52. In steps 384 to 104, pressure increase control is performed on the brake of the rear wheel on the inside of the turn, holding control is performed while the yaw rate difference D7 is constant, and pressure reduction control is performed when the yaw rate difference D7 starts to decrease. Note that the current brake fluid pressure P(t) is the previous brake fluid pressure P(t-1
) is actually determined by whether the difference between the two is between a relatively small negative value and a positive value, and the determination of the magnitude of both is performed in the same way. .

As a result of the determination in S83, if pressure increase is necessary, first proceed in S8.
4, it is determined whether the vehicle is turning to the right based on the current steering angle θ stored in the steering angle memory 112. If turning left, the pressure increase control of the brake 30 of the left rear wheel 28 is performed in steps 385-94, and if turning right, pressure increase control of the brake 34 of the right rear wheel 32 is performed in steps 595-104. It will be done. Since the pressure increase control on either side is the same, the pressure increase control on the left brake 30 will be described as a representative example.

First, 385 is calculated using the following formula (% formula %)) However, A is a constant that calculates the left pressure increase remaining time TACCL, that is, the time to increase the hydraulic pressure of the left brake 30, and the right pressure increase. The remaining time TACCR is cleared.

Subsequently, in S86, it is determined whether the previous brake fluid pressure control was performed on the right brake based on the previous right control flag XRR, and if the result of the determination is NO, S92,
At 93.94, the pressure on the left side is increased while holding the right side. S9
In S93, the right hydraulic pressure control valve 44 is held in the holding state and the previous right control flag XRR is turned OFF, and in S93 the left hydraulic pressure control valve 42 is put in the pressure increasing state, The flag XRL is turned ON, and the remaining pressure increase time T A
, CCL is decremented, and this control is repeated until the left pressure increase remaining time T A CCL becomes O.

On the other hand, the previous brake fluid pressure control was on the right and S8
If the judgment result in step 6 is YES, there is a possibility that there is fluid pressure remaining in the right brake 34, so 387-9
1, while the right brake 34 is being depressurized, 39
At step 3, the pressure of the left brake 30 is increased. S86
If 387 is executed for the first time after the determination result becomes YES, the determination result is YES, and in 388, the opposite side decompression time KDB is changed to the opposite side (right side) remaining decompression time TRD.
, and the opposite side decompression remaining time TRD is decremented in S89. Then, the remaining decompression time on the other side TR
Until D becomes O and the determination result of 390 becomes YES, the right hydraulic pressure control valve 44 is kept in a reduced pressure state in S91,
Further, in S93, the left hydraulic pressure control valve 42 is brought into a pressure increasing state.

If the determination result in S90 is YES, the previous right control flag XRR is turned OFF in S92, and thereafter, from 387 to
90 is skipped and only the left pressure increase control is performed.

Next, the pressure reduction control of 5111 to 116 will be explained.

First, in step 5111, the remaining pressure reduction time TBD, the time during which the hydraulic pressure of the Zunawaji brake 30 or 34 should be reduced, is calculated using the following formula %(). continue,
At 5112, it is determined whether the vehicle is turning to the right or to the left. If the vehicle is turning to the left, the left hydraulic pressure control valve 42 is set to a reduced pressure state at Sl 13.
51 if the right hydraulic pressure control valve 44 is held and the previous left control flag XRL is turned ON and a right turn is being made.
14, the situation is reversed. Then, the remaining decompression time TBD is decremented in 5115, and the remaining decompression time TBD is elapsed and the determination result in 5116 becomes YES.
2 to 115 are repeated.

Furthermore, if it is determined that it is necessary to maintain the brake fluid pressure as a result of the determination in S83, the left and right hydraulic pressure control valves 42 and 44 are held in the retained state by executing step 5107, and then step 8108 is executed.
The remaining pressure increase time TACCR etc. are cleared.

By repeating any of the above pressure increase control, pressure decrease control, and holding control, the left and right brakes 30.3
4 is controlled, the brake on the inside of the turn is applied with appropriate braking force to compensate for the lack of yawing moment, and the actual yaw rate YR is brought closer to the target yaw rate Y□ determined based on the steering angle θ. .

And the difference between the two ■)Y is the standard value. If it is below, the end processing time KTE is set in the end processing remaining time counter EC at 367 in FIG. 6, the determination result at S82 becomes No, and step 5109 is executed. While the content of the end processing remaining time counter EC is greater than the pre-end retention time KTB, the determination result in 5109 is YES, and 3107
．． Holding control is performed in 108, and if the hold time before termination is smaller than the holding time before termination KTB, the remaining pressure increase time TACCL etc. are cleared in 5110, and the pressure reduction time before termination KTDE is set as the remaining pressure reduction time TBD, and the pressure reduction time before termination KTDE is set in 3112 to 116. Decompression takes place for a period of time. After the end of this pressure reduction, the determination result of 369 becomes YES in the flowchart [. of FIG.
The determination result at 810 is NO, and at 8117 the left and right hydraulic pressure control valves 42 and 44 are put into the pressure increasing state, and at 5108 the remaining pressure increase time T A CCL etc. are cleared and the execution of the series of traction steers is completed.

Also, while performing traction steer, brake pedal 1
0 is pressed, the determination result of S60 in FIG. 6 becomes YES, and 370.71 and 5117,10B
The termination process is performed, and the execution of traction steer is terminated.

In this embodiment, as described above, in S2, while the vehicle is traveling straight, the steering angle θ and the actual yaw rate Y, I
The maximum value of the amount of wobbling is determined as the offset amount, and in S3, the detected steering angle θ and actual yaw rate Y are offset toward O by the offset amount, and then the brake fluid pressure is determined. As a result, fluctuations in the steering angle θ and actual yaw ray I''Y* are ignored, and the brake fluid pressure is increased/decreased frequently, causing vibrations in the vehicle body and causing discomfort to the driver. be done.

As is clear from the above explanation, in this embodiment, the rotation sensors 84, 86, 88, 90 and the S of the main controller 96
The vehicle body speed detection means 1 is constituted by the parts that execute 1.ll, and the steering angle detection means 2. An actual rate-related amount detection means 3 is constructed. Also, brake 3034
Actuator 68. The portion of the main control device 96 that executes S46-51, S60-71 and S81-117 constitutes the traction steer means 4, and the portion of the main control device 96 that executes S13-32 constitutes the wobbling amount detection means 5. , S42 to S45 of the main controller 96
The offset means 6 is constituted by the part that executes this.

Additionally, in this embodiment, as described above, the target yaw rate YT is set to a smaller value as the friction coefficient μ of the road surface becomes smaller, so that the occurrence of spin-out can be effectively avoided. Although it is difficult to generate a large actual yaw rate when the friction coefficient μ of the road surface is small, if the target yaw rate YT is set regardless of the size of the friction coefficient The target yaw rate 1-YT is set, and the actual yaw rate Y
In order to bring R closer to the excessively high target yaw rate Yy, excessive braking force is applied to the rear wheel on the inside of the turn, which may cause a spin-out, but in this example, the smaller the friction coefficient μ, the more Since the target yaw rate Ya is set to a small value, the occurrence of spin-out can be effectively avoided. However, in cases where the target yaw rate Ya is mainly set based on a road surface with a low friction coefficient μ, it is not essential to include the road surface μ related amount M in the formula for determining the target yaw rate Ya.

In addition, in this embodiment, the rear wheel 28.3 which is the driving wheel
Turning control is performed by the action of the brakes 30 and 34 of No. 2, and if the rotation of one drive wheel is suppressed in this way, the rotation of the other drive wheel is promoted by the action of the differential device. , actual yaw rate Y,l delays are particularly well avoided.

In this sense, when the front wheels are the driving wheels, it is desirable to perform turning control by applying brakes on the front wheels. However, when applying the brakes on the rear wheels, the nose dive of the vehicle body is usually smaller than when applying the brakes on the front wheels, so if the front wheels are the driving wheels, apply the brakes on the rear wheels. Turning control may also be performed by causing the vehicle to rotate. moreover,
By applying the front and rear brakes together, the delay in actual yaw ray can be more effectively avoided.

Although not illustrated in detail, it goes without saying that the present invention can be implemented with various improvements and changes based on the knowledge of those skilled in the art.

[Brief explanation of drawings]

FIG. 1 is a diagram conceptually showing the configuration of the present invention. FIG. 2 is a system diagram showing a traction steer device according to an embodiment of the present invention, and FIGS. 3 to 7 are flowcharts 1 and 7 showing a control program of a main control device thereof. FIG. 8 is a graph showing the relationship between the friction coefficient ll of the road surface and the road surface μ related quantity M, and FIG.
FIG. 2 is a diagram conceptually showing the configuration of AM. FIG. 10 is a graph for explaining the determination of the offset amount in the traction steer device. 18: Left front wheel 20 Ni brake 22: Right front wheel
24 Ni brake 28: Left rear wheel 30 Ni brake 32: Right rear wheel 34 Ni brake 40 Ni cylinder cut valve 42.44: Hydraulic pressure control valve 62: Accumulator cut valve 68: Actuator 76: Steering device 80: Steering angle sensor 81: Steering torque sensor 84 .86,88.9
0: Rotation sensor 92: Vehicle body 94: Yaw rate sensor 96:
Main control device

Claims (1)

[Scope of Claims] Vehicle speed detection means for detecting the vehicle body speed of an automobile; steering angle detection means for detecting the steering angle of a steering device; and actual yaw rate detection means for detecting an actual yaw rate related amount related to the actual yaw rate of the vehicle body. a related quantity detection means, a target yaw rate related quantity determined based on the vehicle speed and steering angle detected by the vehicle speed detection means and the steering angle detection means, and an actual yaw rate related quantity detected by the actual yaw rate related quantity detection means. traction steer means for controlling the driving force of the wheels so that the difference between the steering angle and the actual yaw rate when the vehicle is traveling straight ahead; and an offset means for offsetting at least one of the detected values toward 0 by an amount corresponding to the amount of wobble detected by the wobble detection means. Features a traction steer device.