JPH0774619B2 - Vehicle acceleration slip prevention device - Google Patents

Description

Description: [Object of the Invention] (Field of Industrial Application) The present invention relates to an acceleration slip prevention device for a vehicle that improves the turning performance of the vehicle.

(Prior Art) Conventionally, there is known an acceleration slip prevention device (traction control device) that prevents slippage of drive wheels that occurs when an automobile is suddenly accelerated. In such a traction control device, when the acceleration slip of the driving wheels is detected, the slip ratio S is controlled so that the friction coefficient μ between the tire and the road surface falls within the maximum range (hatched range in FIG. 15). Here, the slip ratio S is [(VF-VB) / V
F] × 100 (percent), VF is the wheel speed of the driving wheel, and VB is the vehicle speed. That is, when the slip of the driving wheel is detected, the wheel speed VF of the driving wheel is controlled by controlling the engine output so that the slip ratio S is in the shaded range, and the friction coefficient μ between the tire and the road surface is maximum. The range is controlled so that the drive wheels do not slip during acceleration and the acceleration performance of the vehicle is improved.

(Problems to be Solved by the Invention) By the way, a lateral force (side force) generated in a tire is one of the factors that improve the turning performance of a vehicle during turning. By increasing the lateral force, a large cornering force can be obtained and the turning performance can be improved. This lateral force is gradually reduced as the slip ratio S increases, as shown by A in FIG. Therefore, at the position where the friction coefficient μ is in the maximum range, the lateral force is still insufficient, so that there is a problem that the turning performance cannot be sufficiently exhibited.

The present invention has been made in view of the above points, and an object of the present invention is to accelerate a lateral force at the time of turning so as to suppress slippage at the time of turning and improve turning performance of a vehicle. It is to provide an anti-slip device.

[Configuration of the Invention] (Means and Actions for Solving the Problem) The driving wheel speed and the driven wheel speed are detected, a slip amount is calculated according to the difference between the driving wheel speed and the driven wheel speed, and the slip amount is calculated according to the slip amount. In an acceleration slip prevention device for a vehicle configured to reduce the output torque of a driving wheel, a first wheel speed sensor for detecting a wheel speed of one driven wheel of the vehicle and a wheel of the other driven wheel of the vehicle. A second wheel speed sensor for detecting a speed, a third wheel speed sensor for detecting a wheel speed of one driving wheel of the vehicle, and a fourth wheel speed sensor for detecting a wheel speed of the other driving wheel of the vehicle. A turning degree detecting means for detecting a turning degree of the vehicle, and one of the first wheel speed sensor for detecting the turning of the vehicle based on the turning degree detected by the turning degree detecting means. Driven wheel And the wheel speed of the other driven wheel detected by the second wheel speed sensor, whichever is smaller, is VR, and the wheel speed of one driving wheel detected by the third wheel speed sensor and the above Of the wheel speeds of the other drive wheels detected by the fourth wheel speed sensor, the larger wheel speed is VF, and the slip amount calculating means for calculating the slip amount according to the wheel speed VF-wheel speed VL; An acceleration slip prevention device for a vehicle, comprising: an engine output calculation unit that determines an engine output according to a slip amount calculated by a slip amount calculation unit.

(Embodiment) Hereinafter, an acceleration slip prevention device for a vehicle according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing an acceleration slip prevention device for a vehicle. The figure shows a front-wheel drive vehicle. WFR is the front right wheel, W
FL is the front left wheel, WRR is the rear right wheel, and WRL is the rear left wheel. Further, 11 is a wheel speed sensor for detecting the wheel speed VFR of the front right wheel (driving wheel) WFR, 12
Is a wheel speed sensor for detecting the wheel speed VFL of the front left wheel (driving wheel) WFL, 13 is a wheel speed sensor for detecting the wheel speed VRR of the rear right wheel (driven wheel) WRR, and 14 is a rear left wheel (driven). Theory) A wheel speed sensor for detecting the wheel speed VRL of WRL. The wheel speeds VFR, VFL, VRR, VRL detected by the wheel speed sensors 11 to 14 are traction controllers.
Entered in 15. The traction controller 15 sends a control signal to the engine 16 to perform control to prevent the drive wheels from slipping during acceleration. This engine 16 is a main throttle valve whose opening is operated by an accelerator pedal.
In addition to THm, a sub throttle valve whose opening is controlled by a control signal Θs from the traction controller 15 described above.
It has THs, and controls the driving force of the engine 16 by controlling the opening of the sub-throttle valve THs by a control signal from the traction controller 15.

Further, 17 is a wheel cylinder for braking the right front wheel WFR, and 18 is a wheel cylinder for braking the front left wheel WFL. Normally, pressure oil is supplied to these wheel cylinders via a master bag and a master cylinder (not shown) by operating a brake pedal (not shown). When the traction control is activated, pressure oil can be supplied from another route described below. Supply of pressure oil from the hydraulic pressure source 19 to the wheel cylinder 17 is performed via the inlet valve 17i.
Discharge pressure oil from 7 to reservoir 20 by outlet valve 1
Done through 7o. Further, the supply of pressure oil from the oil pressure source 19 to the wheel cylinder 18 is performed via the ellet valve 18i, and the discharge of pressure oil from the wheel cylinder 18 to the reservoir 20 is performed via the outlet valve 18o. . The traction controller 15 controls the opening and closing of the inlet valves 17i and 18i and the outlet valves 17o and 18o.

Next, referring to FIG. 2, the traction controller described above.
The detailed configuration of 15 will be described. Wheel speeds VFR and VFL of the driving wheels detected by the wheel speed sensors 11 and 12
Is sent to the high vehicle speed selection unit (SH) 31, and the higher wheel speed of the wheel speed VFR and the wheel speed VFL is selected and output. At the same time, the wheel speeds VFR and VFL of the drive wheels detected by the vehicle speed sensors 11 and 12 are averaged by the averaging section 32 to calculate the average wheel speed (VFR + VFL) / 2. The wheel speed output from the high vehicle speed selection unit 31 is multiplied by the variable KG in the weighting unit 33, and the average wheel speed output from the averaging unit 32 is changed by the variable (1-
KG) and then sent to the adder 35 to be added together to obtain the drive wheel speed VF. The variable KG is a variable that changes according to the centripetal acceleration GY as shown in FIG. As shown in FIG. 3, the centripetal acceleration GY has a predetermined value (for example, 0.1 g,
However, g is proportional to centripetal acceleration up to heavy acceleration, and is set to "1" when it is more than that.

Further, the wheel speeds of the driven wheels detected by the wheel speed sensors 13 and 14 are input to the low vehicle speed selection section 36, and the smaller wheel speed is selected. Further, the wheel speed sensor 13,1
The wheel speed of the driven wheels detected in 4 is input to the high vehicle speed selection unit 37, and the larger wheel speed is selected. And
The smaller wheel speed selected by the low vehicle speed selection unit 36 is multiplied by a variable Kr in the weighting unit 38, and the high vehicle speed selection unit
The weighting unit 39 multiplies the larger wheel speed selected at 37 by a variable (1-Kr). This variable Kr changes between "1" and "0" according to the centripetal acceleration GY as shown in FIG.

The wheel speeds output from the weighting section 38 and the weighting section 39 are added in an adding section 40 to obtain a driven wheel speed VR, and the driven wheel speed VR is multiplied by (1 + α) in a multiplying section 40 '. The target drive wheel speed VΦ is set.

Then, the drive wheel speed VF output from the adder 35 and the target drive wheel speed VΦ output from the multiplier 40 'are subtracted by a subtractor 41 to obtain a slip amount DVi' (= VF-V
Φ) is calculated. The slip amount DVi 'is further corrected in the adder 42 according to the centripetal acceleration GY and the rate of change G of the centripetal acceleration GY. That is, the slip correction amount Vg that changes according to the centripetal acceleration GY as shown in FIG. 5 is set in the slip amount correction unit 43, and the centripetal acceleration as shown in FIG. 6 is set in the slip amount correction unit 44. Slip correction amount that changes according to the change rate G of GY
Vd is set. Then, in the addition unit 42, the slip correction amounts VVi and Vg are added to the slip amount DVi ′ output from the subtraction unit 41 to obtain the slip amount DVi.

This slip amount DVi is, for example, a sampling time T of 15 ms.
Is sent to the calculation unit 45a in the TSn calculation unit 45, and the slip amount DV
The correction torque TSn is obtained by integrating i while being multiplied by the coefficient KI. That is, the correction torque obtained by integrating the slip amount DVi, that is, the integral correction torque TSn is obtained as TSn = ΣSn = ΣKI · DVi (KI is a coefficient that changes according to the slip amount DVi).

Further, the slip amount DVi is TPn at every sampling time T.
The correction torque TPn proportional to the slip amount DVi is sent to the calculation unit 46a of the calculation unit 46 and is calculated. That is, the correction torque proportional to the slip amount DVi, that is, the proportional correction torque TPn is obtained as TPn = DVi · Kp (Kp is a coefficient).

The driven wheel speed VR output from the adder 40 is input to the reference torque calculator 47 as the vehicle body speed VB. The reference torque calculation unit 47 calculates the reference torque TG that can be transmitted without causing slip on the road surface having the friction coefficient μ based on the driven wheel speed VR.

Then, the reference torque TG and the integral type correction torque TSn
Is subtracted in the subtraction unit 48, and further subtraction with the proportional correction torque TPn is performed in the subtraction unit 49.
In this way, the target torque TΦ is calculated as TΦ = TG-TSn-TPn.

Then, the target torque TΦ is converted by the torque / throttle opening conversion unit 50 into an engine torque for generating the target torque TΦ and converted into an auxiliary throttle valve opening for generating the engine torque. It Then, by adjusting the opening Θ of the sub-throttle valve, the output torque of the engine is reduced to the target engine torque TΦ.
Controlled to be.

In addition, the wheel speeds VRR and VRL of the driven wheels are calculated by the centripetal acceleration calculation unit 53.
The centripetal acceleration GY ′ is sent to determine the turning degree.
Is required. This centripetal acceleration GY 'is the centripetal acceleration correction unit.
54, the centripetal acceleration GY ′ is corrected according to the vehicle speed.

That is, GY = Kv · GY ′, and the coefficient Kv is shown in FIGS.
As shown in FIG. 12, the centripetal acceleration GY is corrected according to the vehicle speed by changing Kv according to the vehicle speed.

By the way, from the wheel speed VFR of the driving wheels, the high vehicle speed selection unit 3
The wheel speed of the 7-output driven wheel having the larger value is subtracted by the subtracting unit 55. Further, the subtracting unit 56 subtracts the wheel speed of the driven wheel having the larger value from the high vehicle speed selecting unit 37 output from the driving wheel wheel speed VFL.

The output of the subtraction unit 55 is multiplied by KB in the multiplication unit 57 (0 <KB <
1), and the output of the subtraction unit 56 is (1
-KB) and then added by the adder 59 to obtain the slip amount DVFR of the right drive wheel. At the same time, the output of the subtraction unit 56 is multiplied by KB in the multiplication unit 60, and the subtraction unit 55
The output of is multiplied by (1-KB) in the multiplication unit 61 and then added
It is added at 62 to be the slip amount DVFL of the left drive wheel. The variable KB changes according to the elapsed time from the start of control of the traction control as shown in FIG. 13, and is set to "0.5" at the start of control of the traction control. Is set to approach.
For example, when KB is set to "0.8", when one drive wheel slips, the other drive wheel recognizes that only 20% of one drive wheel slips and brake control is performed. ing. This is because if the brakes on the left and right drive wheels are made completely independent, when only one drive wheel is braked and rotation is reduced, the drive wheel on the other side slips and the brake is applied due to the action of the differential. Is repeated, which is not preferable. The slip amount DVFR of the right drive wheel is differentiated in a differentiator 63 to calculate its temporal change amount, that is, the slip acceleration GFR, and the slip amount DVFL of the left drive wheel is differentiated in a differentiator 64 to obtain its time. The dynamic change amount, that is, the slip acceleration GFL is calculated. Then, the slip acceleration GFR is sent to the brake fluid pressure change amount (ΔP) calculating section 65, and the brake fluid for suppressing the slip acceleration GFR is referred to by referring to the GFR (GFL) -ΔP conversion map shown in FIG. The pressure change amount ΔP is obtained. Similarly, the slip acceleration GFL is sent to the brake fluid pressure change amount (ΔP) calculation unit 66, and the slip acceleration GFL is suppressed by referring to the GFR (GFL) -ΔP conversion map shown in FIG. The change amount ΔP of the brake fluid pressure is calculated.

In FIG. 14, when the brake is applied at the time of turning, the inner wheel side at the time of turning is indicated by a broken line a in order to strengthen the braking of the drive wheels on the inner wheel side.

Next, the operation of the vehicle acceleration slip prevention device according to the embodiment of the present invention configured as described above will be described. In FIGS. 1 and 2, the wheel speed sensors 13 and 14 are shown.
The wheel speeds of the driven wheels (rear wheels) output from are input to the high vehicle speed selection unit 36, the low vehicle speed selection unit 37, and the centripetal acceleration calculation unit 53. In the low vehicle speed selection unit 36, the smaller wheel speed is selected from the left and right driven wheels, and the high vehicle speed selection unit 37 is selected.
In, the larger wheel speed of the left and right driven wheels is selected. During normal straight running, if the wheel speeds of the left and right driven wheels are the same, the low vehicle speed selection unit 36
The same wheel speed is selected from the high vehicle speed selection unit 37.
Further, in the centripetal acceleration calculation unit 53, the wheel speeds of the left and right driven wheels are input, and the turning degree when the vehicle is turning from the wheel speeds of the left and right driven wheels, that is, how sharp a turn is made. The degree of whether or not it is calculated is calculated.

Hereinafter, how the centripetal acceleration calculation unit 53 calculates the centripetal acceleration will be described. Since the rear wheels of the driven vehicle are the driven wheels, the vehicle speed at that position can be detected by the wheel speed sensor regardless of the slip caused by driving, so Ackermann geometry can be used. That is, in the steady turn, the centripetal acceleration GY ′ is calculated as GY ′ = v ² / r (1) (v = vehicle speed, r = turn radius).

For example, when the vehicle is turning to the right as shown in FIG. 16, the turning center is Mo, the distance from the turning center Mo to the inner wheel side (WRR) is r1, the tread is Δr, and the inner wheel is When the wheel speed on the side (WRL) is v1 and the wheel speed on the outer wheel side is v2, v2 / v1 = (Δr + r1) / r1 (2).

Then, the above equation (1) is modified to be 1 / r1 = (v2-v1) / Δr · v1 (3). Then, the centripetal acceleration GY ′ based on the inner ring side
Is calculated as GY ′ = v1 ² / r1 = v1 ² · (v2-v1) / Δr · v1 = v1 · (v2-v1) / Δr (4).

That is, the centripetal acceleration GY 'is calculated by the equation (4). By the way, since the wheel speed v1 on the inner wheel side is smaller than the wheel speed v2 on the outer wheel side during turning, the centripetal acceleration GY ′ is calculated using the wheel speed v1 on the inner wheel side.
Y'is calculated smaller than the actual value. Therefore, the weighting unit 3
The coefficient KG multiplied by 3 has a smaller value as the centripetal acceleration GY ′ is estimated to be smaller. Therefore, since the drive wheel speed VF is estimated to be small, the slip amount DV '(VF-VΦ)
Is underestimated. As a result, the target torque TΦ is largely estimated, and the target engine torque is largely estimated, so that a sufficient driving force is applied even during turning.

By the way, in the case of extremely low speed, as shown in FIG.
The distance from the inner wheel side to the center of turning M0 is r1, but in vehicles that understeer as speed increases,
The center of turning turns to M, and the distance is r (r> r1). Even when the speed is increased in this way, since the turning radius is calculated as r1, the centripetal acceleration GY ′ calculated based on the equation (1) is calculated as a value larger than the actual value. Therefore, the centripetal acceleration GY ′ calculated by the centripetal acceleration calculation unit 53 is sent to the centripetal acceleration correction unit 54 so that the centripetal acceleration GY becomes small at high speed.
The centripetal acceleration GY 'is multiplied by the coefficient Kv in FIG. This variable Kv is set to decrease according to the vehicle speed,
It may be set as shown in FIG. 8 or FIG. In this way, the centripetal acceleration GY corrected by the centripetal acceleration correction unit 54 is output.

On the other hand, as the speed increases, oversteering (r <
r1) In the vehicle, the centripetal-acceleration correction unit 54 performs a correction that is completely opposite to the above-described understeering vehicle. That is, any one of the variables Kv in FIG. 10 to FIG. 12 is used to correct the centripetal acceleration GY ′ calculated by the centripetal acceleration calculation unit 53 as the vehicle speed increases.

By the way, the smaller wheel speed selected by the low vehicle speed selection unit 36 is multiplied by a variable Kr in the weighting unit 38 as shown in FIG. 4, and the high wheel train selected by the high vehicle speed selection unit 37 is weighted by the weighting unit. At 39 is multiplied by the variable (1-Kr). The variable Kr is set to "1" at the time of turning such that the centripetal acceleration GY becomes larger than 0.9 g, for example, and the centripetal acceleration GY
When is less than 0.4g, it is set to "0".

Therefore, for turning in which the centripetal acceleration GY is larger than 0.9 g, the vehicle speed of the low speed among the driven wheels output from the low vehicle speed selection unit 36, that is, the wheel speed on the inner wheel side during steering is selected. It Then, the weighting units 38 and 39
The wheel speed output from the addition section 40 adds the wheel speed to the driven wheel speed VR, and the driven wheel speed VR is the multiplication section.
At 40 ', the target drive wheel speed VΦ is multiplied by (1 + α).

In addition, after the wheel speed of the larger one of the wheel speeds of the drive wheels is selected by the high vehicle speed selection unit 31, the weighting unit 33 multiplies the variable KG by a variable KG as shown in FIG. Further, the average vehicle speed of the drive wheels calculated by the averaging unit 32 (VFR + VF
L) / 2 is multiplied by (1-KG) in the weighting unit 34, and is added to the output of the weighting unit 33 and the adding unit 35 to obtain the driving wheel speed VF. Therefore, the centripetal acceleration GY is, for example, 0.
When the weight is 1g or more, KG = 1, so the high vehicle speed selection unit 31
The wheel speed of the larger drive wheel of the two drive wheels output from is output. That is, when the turning degree of the vehicle is increased and the centripetal acceleration GY is, for example, 0.9 g or more, “KG = Kr = 1” is satisfied, so that the driving wheel side drives the wheel speed of the outer wheel side, which has a large wheel speed, to the driving wheel side. Speed VF, and the wheel speed on the inner wheel side with the smaller wheel speed on the driven wheel side is the driven wheel speed.
VR, and the slip amount DVi ′ calculated by the subtraction unit 41
Since (= VF-VΦ) is set, the slip amount DVi 'is largely estimated. Therefore, since the target torque TΦ is underestimated, the output of the engine is reduced, the slip ratio S can be reduced, and the lateral force A can be increased as shown in FIG. You can increase the force and make a safe turn.

In the slip amount correcting unit 43, the slip amount correcting unit 43 adds the slip correcting amount Vg as shown in FIG. 5 only when the turning occurs when the centripetal acceleration GY is generated.
At 44, the slip amount Vd as shown in FIG. 6 is added. For example, assuming that a curve turns at a right angle, the centripetal acceleration GY and its temporal change rate G have positive values in the first half of the turn, but the temporal change rate of the centripetal acceleration GY in the latter half of the curve. G has a negative value. Therefore, in the first half of the curve, the slip correction amount VVi (> 0) and the slip correction amount Vd (> 0) shown in FIG.
i, and the slip correction amount Vg in the latter half of the curve
(> 0) and the slip correction amount Vd (<0) are added to obtain the slip amount DVi. Therefore, by estimating the slip amount DVi in the second half of the turn as smaller than the slip amount DVi in the first half of the turn, the engine output is reduced in the first half of the turn to increase the lateral force and improve the turning performance. In the above, the engine output is recovered more than in the first half so as to improve the accelerating property of the vehicle after the turning is completed.

In this way, the corrected slip amount DVi is, for example, 15 m.
It is sent to the TSn calculator 45 at the sampling time T of s. In the TSn calculator 45, the slip amount DVi is multiplied by the coefficient KI and integrated to obtain the correction torque TSn.
That is, the correction torque obtained by integrating the slip amount DVi, that is, the integral correction torque TSn is obtained as TSn = ΣKI · DVi (KI is a coefficient that changes according to the slip amount DVi).

Further, the slip amount DVi is TPn at every sampling time T.
The correction torque TPn is sent to the calculation unit 46 and is calculated. That is, the correction torque proportional to the slip amount DVi, that is, the proportional correction torque TPn is obtained as TPn = DVi × Kp (Kp is a coefficient).

The driven wheel speed VR output from the adder 40 is input to the reference torque calculator 47 as the vehicle body speed VB. Then, in the reference torque calculation unit 47, the vehicle speed VB
The reference torque TG that can be transmitted to the road surface having the friction coefficient μ without slipping is calculated based on

Then, the reference torque TG and the integral type correction torque TSn
Subtraction with and is performed in the subtraction unit 48, and the proportional correction torque TPn is further performed in the subtraction unit 49. In this way, the target torque TΦ is calculated as TΦ = TG-TSn-TPn.

Then, this target torque TΦ is sent to the torque / throttle opening conversion unit 50 and converted into a sub-throttle valve opening Θs for generating the target torque TΦ, and the sub-throttle according to the sub-throttle valve opening Θs. The valve THs is controlled to open and close.

By the way, from the wheel speed VFR of the driving wheels, the high vehicle speed selection section is selected.
The wheel speed of the 37-output driven wheel having the larger value is subtracted by the subtraction unit 55. Further, the subtracting unit 56 subtracts the wheel speed of the driven wheel having the larger value from the high vehicle speed selecting unit 37 output from the driving wheel wheel speed VFL. Therefore, the subtraction unit 55
By estimating the outputs of 56 and 56 to be small, even if a difference in the left and right driven wheel speeds occurs due to the difference in the inner wheels during turning, braking operation due to false detection of slip is prevented, and running stability is improved.

The output of the subtraction unit 55 is multiplied by KB in the multiplication unit 57 (0 <KB <
1), and the output of the subtraction unit 56 is (1
-KB) times and then added in the adder 59 to obtain the slip amount DVFR of the right drive wheel. At the same time, the output of the subtraction unit 56 is multiplied by KB in the multiplication unit 60, and the subtraction unit 55
The output of is multiplied by (1-KB) in the multiplication unit 61 and then added
It is added at 62 to be the slip amount DVFL of the left drive wheel. The variable KB changes according to the elapsed time from the start of control of the traction control as shown in FIG. 13, and is set to "0.5" at the start of control of the traction control. Is set to approach.
That is, when the slip of the driving wheels is reduced by the brakes, both brakes can be simultaneously applied at the start of braking to reduce an uncomfortable steering wheel shock at the start of brake braking on a split road, for example. . Brake control is continued and KB is 0.8.
If so, the operation will be described. In this case, when the slip occurs in only one drive wheel, the brake control is performed by recognizing that the other drive wheel also slips by 20% of the one drive wheel. This is because if the brakes on the left and right drive wheels are made completely independent, the brake will be applied to only one drive wheel and the rotation will decrease. This is because it is repeated, which is not preferable. The slip amount DVFR of the above right drive wheel is calculated by the differential unit 63
Is differentiated to calculate the temporal change amount, that is, the slip acceleration GFR, and the slip amount DVFL of the left drive wheel is differentiated in the differentiating section 64 to calculate the temporal change amount, that is, the slip acceleration GFL. . Then, the slip acceleration GFR is the brake fluid pressure change amount (Δ
P) It is sent to the calculation unit 65 and GFR (GFL) -shown in FIG.
The change amount ΔP of the brake fluid pressure for suppressing the slip acceleration GFR is obtained by referring to the ΔP conversion map. Similarly, the slip acceleration GFL is sent to the brake fluid pressure change amount (ΔP) calculation unit 66, and GFR (GF) shown in FIG.
L) -ΔP conversion map is referred to, slip acceleration GF
A change amount ΔP of the brake fluid pressure for suppressing L is obtained.

In FIG. 14, when the brake is applied during turning, in order to strengthen the braking of the drive wheels on the inner wheel side, the inner wheel side during turning is indicated by a broken line a. In this way, when the vehicle is turning, the load is moved to the outer wheel side and the inner wheel side is more likely to slip. By making the change amount ΔP of the brake fluid pressure larger on the inner wheel side than on the outer wheel side, At times, it is possible to prevent the inner ring side from slipping.

Although the centripetal acceleration GY ′ in the centripetal acceleration computing unit 56 in the above-described embodiment is based on the wheel speed x1 on the inner wheel side, the invention is not limited to this, and the wheel speed v1 on the inner wheel side and the wheel speed v2 on the outer wheel side are compared. May be used as a reference, or the wheel speed v2 on the outer wheel side may be used as a reference.

For example, a case where the centripetal acceleration GY ′ is calculated based on the average of the wheel speed v1 on the inner wheel side and the wheel speed v2 on the outer wheel side will be described. In this case, the centripetal acceleration GY ′ is substituted by v = v2 + v1 / 2, r = (r1 + Δr) / 2 into the first expression, and is transformed using the expression (2), GY ′ = (v2 ² − v1 ² ) / 2 · Δr (5)

On the other hand, when the wheel speed v2 on the outer wheel side is used as a reference, substituting v = v2, r = r1 + Δr into the first equation above and transforming using equation (2), GY ′ = (v2-v1) v2 / Δr (6)

Therefore, the centripetal acceleration G is based on the wheel speed v2 on the outer wheel side.
When Y ′ is calculated, the centripetal acceleration GY ′ is estimated to be larger than the actual value. Therefore, the target torque TΦ is estimated to be small by estimating the slip amount DV ′ to be larger than the actual value, and the wheel speed v1 on the inner wheel side is used as a reference. The engine output torque is reduced and the lateral force is increased to improve turning performance. When the centripetal acceleration GY ′ is calculated based on the average of the wheel speed v1 on the inner wheel side and the wheel speed v2 on the outer wheel side, the centripetal acceleration GY ′ is based on the wheel speed v1 on the inner wheel side as described above. In this case, since the output control of the engine is performed intermediate between the case and the wheel speed v2 on the outer wheel side, it is possible to obtain an intermediate characteristic that places a specific weight on both the driving force and the turning performance during turning. .

[Advantages of the Invention] As described in detail above, according to the present invention, it is possible to provide an acceleration slip prevention device for a vehicle that can effectively suppress the occurrence of slip during turning and can safely turn.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of a vehicle acceleration slip prevention device according to an embodiment of the present invention, and FIG. 2 is a block diagram showing control of the traction controller of FIG. 3 shows the relationship between the centripetal acceleration GY and the variable KG, FIG. 4 shows the relationship between the centripetal acceleration GY and the variable Kr, and FIG. 5 shows the relationship between the centripetal acceleration GY and the slip correction amount Vg. 6 and 6 are diagrams showing the relationship between the rate of change G in centripetal acceleration over time and the slip correction amount Vd, and FIGS. 7 to 12 are diagrams showing the relationship between the vehicle body speed VB and the variable Kv, respectively.
FIG. 14 is a diagram showing the change over time of the variable KB from the start of the brake control, FIG. 14 is a diagram showing the relationship between the time variation GFR (GFL) of the slip amount and the variation ΔP of the brake fluid pressure, and FIG. 15 is FIG. 16 is a diagram showing a relationship between a slip ratio S, a friction coefficient μ between a tire and a road surface, and a lateral force (side force). FIG. 16 is a diagram showing turning radii r1, r and tread Δr when the vehicle is making a right turn. Is. 11-14 Wheel speed sensor, 15 Traction controller, 45 TSn calculation unit, 46 TPn calculation unit, 47 Reference torque calculation unit, 50 Torque / throttle opening conversion unit, 53 ... … Centripetal acceleration calculation unit, 54 …… Centripetal acceleration correction unit.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP 62-265428 (JP, A) JP 62-91324 (JP, A) JP 62-91325 (JP, A) JP 63- 38064 (JP, A)

Claims (1)

[Claims] 1. A drive wheel speed and a driven wheel speed are detected, and a slip amount is calculated according to a difference between the drive wheel speed and the driven wheel speed,
In an acceleration slip prevention device for a vehicle configured to reduce the output torque of a drive wheel according to this slip amount, a first wheel speed sensor that detects a wheel speed of one driven wheel of the vehicle and the other of the vehicle Second wheel speed sensor for detecting the wheel speed of the driven wheel of the vehicle, a third wheel speed sensor for detecting the wheel speed of one driving wheel of the vehicle, and a third wheel speed sensor for detecting the wheel speed of the other driving wheel of the vehicle. No. 4, a wheel speed sensor, a turning degree detecting means for detecting a turning degree of the vehicle, and the first wheel speed sensor when the turning of the vehicle is detected by the turning degree detected by the turning degree detecting means. The smaller wheel speed of the detected wheel speed of one driven wheel and the wheel speed of the other driven wheel detected by the second wheel speed sensor is VR, and is detected by the third wheel speed sensor. one The wheel speed of the larger one of the wheel speed of the driving wheel and the wheel speed of the other driving wheel detected by the fourth wheel speed sensor is VF, and the slip amount is calculated according to the wheel speed VF-wheel speed VL. An acceleration slip prevention device for a vehicle, comprising: a slip amount calculating means for controlling the engine and an engine output calculating means for determining the output of the engine according to the slip amount calculated by the slip amount calculating means.