Turning control apparatus for vehicle

• US 5,276,624 A
• Filed: 11/23/1992
• Issued: 01/04/1994
• Est. Priority Date: 01/25/1990
• Status: Expired due to Term

• Current Assignee: Mitsubishi Jidosha Kogyo Kabushiki Kaisha
• Original Assignee: Mitsubishi Jidosha Kogyo Kabushiki Kaisha
• Inventors: Yoshida, Hiroshi, Otake, Katsunori, Isoda, Keiji, Shigehara, Toshio, Miyata, Yasunobu, Hashiguchi, Masayuki, Yuasa, Hiroo, Osaki, Masayoshi, Yoshida, Hiroaki, Yamada, Kiichi, Ito, Masayoshi, Tanaka, Tadao, Tani, Masanori
• Primary Examiner(s): Black, Thomas G.
• Assistant Examiner(s): PARK, COLLIN
• Application Number:
  US07/980,425
• Time in Patent Office: 407 Days
• Field of Search: 364/424.05, 364/426.01, 364/426.02, 364/426.03, 180/197, 180/282
• US Class Current: 701/72
• CPC Class Codes: B60K 28/16 responsive to, or preventing, skidding of wheels brake control systems for vehicle drive stability B60T8/1755; arrangements responsive to a speed condition for adjusting wheel braking force B60T8/32; control of vehicle driving stability otherwise than by controlling the propulsion unit only B60W30/02; preventing wheel slippage by reducing power in rail vehicles B61C15/00
• CPC Class Codes: B60T 2201/16 Curve braking control, e.g. turn control within ABS control algorithm
• CPC Class Codes: B60T 2210/12 Friction
• CPC Class Codes: B60T 8/172 Determining control parameters used in the regulation, e.g. by calculations involving measured or detected parameters B60T8/17551 takes precedence
• CPC Class Codes: B60T 8/175 Brake regulation specially adapted to prevent excessive wheel spin during vehicle acceleration, e.g. for traction control safety devices for propulsion unit control responsive to, or preventing, skidding of wheels B60K28/16
• CPC Class Codes: B62D 15/02 Steering position indicators ; Steering position determination; Steering aids

Abstract

In a turning control apparatus for a vehicle, a torque calculation unit calculates a target lateral acceleration of the vehicle according to detection signals from a steering angle sensor for detecting the direction of a steering wheel and a vehicle speed sensor for detecting the speed of the vehicle. It then sets target driving torque of the engine according to the target lateral acceleration. An electronic control unit controls the operation of a torque control device for reducing driving of the engine so that the driving torque of the engine is a target driving torque independent of manipulation by the driver. This thereby rapidly estimates lateral acceleration applied to the vehicle during turning and prevents control delay to enable stable and positive traveling through a curved road.

Claims

1. A turning control apparatus for a vehicle comprising:

torque control means for controlling a driving torque of a vehicle engine independent of manipulation by the driver;

a steering angle sensor for detecting a steering angle of a vehicle steering wheel;

a vehicle speed sensor for detecting traveling speed of the vehicle;

a torque calculation unit for setting a target lateral acceleration of the vehicle as a lateral acceleration, estimated as traveling on a road having a predetermined frictional coefficient according to said steering angle detected by said steering angle sensor and said vehicle speed detected by said vehicle speed sensor, and for converting said target lateral acceleration to a target driving torque of the vehicle engine according to a preset relation using solely said target lateral acceleration as a lateral acceleration of the vehicle only upon detecting a steering angle by said steering angle sensor; and

an electronic control unit for controlling operation of said torque control means so that the driving torque of the vehicle engine is equal to said target driving torque set by said torque calculation unit.

2. The turning control apparatus for a vehicle of claim 1 wherein said torque calculation unit limits the varying of the setting of said target driving torque to a value below a predetermined variance from said previously set target driving torque.

3. The turning control apparatus for a vehicle of claim 1 wherein said electronic control unit interrupts control of the operation of the torque control means when the detected traveling speed is less than a predetermined value.

4. The turning control apparatus for a vehicle of claim 1 wherein said electronic control unit controls operation of said torque control means when said calculated target lateral acceleration is greater than a predetermined value.

5. The turning control apparatus for a vehicle of claim 1 further comprising:

lateral acceleration detection means for detecting lateral acceleration applied to the vehicle, wherein said torque calculation unit sets the target driving torque of the vehicle engine according solely to an actual lateral acceleration detected by said lateral acceleration detection means as the lateral acceleration of the vehicle in place of the target lateral acceleration only upon the steering angle sensor failing to detect a steering angle, and further alternatively sets the target driving torque of the vehicle engine according solely to the target lateral acceleration as the lateral acceleration of the vehicle only upon detecting a steering angle by the steering angle sensor.

6. The turning control apparatus for a vehicle of claim 1 further comprising:

a pair of wheel speed sensors for detecting right and left driven wheel speeds;

steering angle neutral position determination means for determining a neutral steering angle according to said detected right and left wheel speeds and said detected steering angle; and

lateral acceleration detection means for detecting actual lateral acceleration applied to the vehicle, wherein said torque calculation unit sets the target driving torque of the vehicle according to the actual lateral acceleration detected until the neutral steering angle is determined, and sets the target driving torque of the vehicle according the target lateral acceleration after the neutral steering angle is determined.

7. The turning control apparatus for a vehicle of claim 6 further comprising:

learning correction interruption means for interrupting determining of the neutral steering angle while said electronic control unit is controlling operation of said torque control means, after determining said neutral steering angle.

8. The turning control apparatus for a vehicle of claim 1 further comprising:

slip condition detection means for detecting a slip condition of right and left driving wheels of the vehicle; and

a slip prevention torque calculation unit for calculating a slip prevention target driving torque of the vehicle engine for slip prevention according to said detected slip condition, wherein said electronic control unit controls operation of said torque control means so that driving torque of the vehicle engine is equal to any one of the target driving torque, according to target lateral acceleration, set by said torque calculation unit and the slip prevention target driving torque set by said slip prevention torque calculation unit.

9. A turning control apparatus for a vehicle comprising:

torque control means for reducing a driving torque of a vehicle engine independent of manipulation by a vehicle driver;

a steering angle sensor for detecting a steering angle of a vehicle steering wheel;

a vehicle speed sensor for detecting traveling speed of the vehicle;

acceleration calculation means for setting a target lateral acceleration of the vehicle as a lateral acceleration, estimated as traveling on a road having a predetermined frictional coefficient according to said steering angle detected by said steering angle sensor and said vehicle traveling speed detected by said vehicle speed sensor, and for converting said target lateral acceleration to a target longitudinal direction acceleration of the vehicle according to a preset relation using solely said target lateral acceleration as a lateral acceleration of the vehicle only upon detecting a steering angle by the steering angle sensor;

a torque calculation unit for setting a target driving torque according to said target longitudinal direction acceleration converted by said acceleration calculation means; and

an electronic control unit for controlling operation of said torque control means so that the driving torque of the vehicle engine is equal to the target driving torque set by said torque calculation unit.

10. The turning control apparatus for a vehicle of claim 9 wherein said target lateral acceleration GYO is calculated by the following equation:

##EQU24## wherein l is a wheel base of the vehicle, A is a stability factor, V is the detected vehicle traveling speed, and δ

is the detected steering angle.

11. The turning control apparatus for a vehicle of claim 9,

wherein said target driving torque is set lower as the set target lateral acceleration increases.

12. The turning control apparatus for a vehicle of claim 9 wherein said target driving torque is set lower as the detected vehicle speed increases.

13. The turning control apparatus for a vehicle of claim 9 wherein said torque calculation unit sets target driving torque according to the calculated target longitudinal direction acceleration and a road-load torque.

14. The turning control apparatus for a vehicle of claim 13 wherein said road-load torque includes a rolling drag component and a cornering drag component of the vehicle.

15. The turning control apparatus for a vehicle of claim 14 further comprising:

lateral acceleration detection means for detecting actual lateral acceleration applied to the vehicle, wherein said cornering drag component varies with the detected actual lateral acceleration of the vehicle.

16. The turning control apparatus for a vehicle of claim 9 further comprising:

longitudinal direction acceleration detection means for detecting actual longitudinal direction acceleration applied to the vehicle, wherein said electronic control unit sets the target driving torque according to a deviation between the calculated target longitudinal direction acceleration and an actual longitudinal direction acceleration applied to the vehicle.

17. The turning control apparatus for a vehicle of claim 9 further comprising:

stability factor calculation means for calculating a stability factor of the vehicle according to said detected steering angle and said detected vehicle traveling speed, wherein said acceleration calculation means calculates target lateral acceleration of the vehicle according to said stability factor and calculates target longitudinal direction acceleration of the vehicle according to said calculated target lateral acceleration.

18. A turning control apparatus for a vehicle comprising:

torque control means for controlling a driving torque of a vehicle engine independent of manipulation by a vehicle driver;

a vehicle speed sensor for detecting traveling speed of the vehicle;

a steering angle sensor for detecting a steering angle of a vehicle steering wheel;

lateral acceleration detection means for detecting actual lateral acceleration applied to the vehicle during turning of the vehicle;

lateral acceleration calculation means for setting a target lateral acceleration of the vehicle as a lateral acceleration, estimated as traveling on a road having a predetermined friction coefficient according to said steering angle detected by said steering angle sensor and said vehicle speed detected by said vehicle speed sensor;

friction coefficient estimation means for estimating a friction coefficient of a road surface by comparing said target lateral acceleration set by said lateral acceleration calculation means and the actual lateral acceleration detected by said lateral acceleration detection means;

a plurality of graphs indicating a relationship between target lateral acceleration set by said lateral acceleration calculation means and a target driving torque relative to the friction coefficient of the road surface;

a torque calculation unit for selecting one of said plurality of graphs corresponding to the friction coefficient estimated by said friction coefficient estimation means and for converting said target lateral acceleration set by said lateral acceleration calculation means to a target driving torque according to said selected one of a plurality of graphs using solely said target lateral acceleration set by said lateral acceleration calculation means as a lateral acceleration of the vehicle only upon detecting a steering angle by said steering angle sensor; and

an electronic control unit for controlling operation of said torque control means so that the driving torque of the vehicle engine is equal to the target driving torque set by said torque calculation unit.

19. A method of turning control for a vehicle comprising the steps of:

(a) detecting a steering angle of a vehicle steering wheel;

(b) detecting a traveling speed of the vehicle;

(c) setting a target lateral acceleration of the vehicle as a lateral acceleration, estimated as traveling on a road having a predetermined friction coefficient according to the steering angle and the vehicle speed detected respectively in steps (a) and (b);

(d) converting said target lateral acceleration set in step (c) to a target driving torque of a vehicle engine using solely said target lateral acceleration as a lateral acceleration of the vehicle according to a preset relation only upon detecting a steering angle in step (a); and

(e) controlling a driving torque of the vehicle engine equal to said target driving torque set in step (d).

20. The turning control method of claim 19 wherein the reduction of the driving torque of the vehicle engine is limited to a value below a predetermined variance from the previous driving torque.

21. The turning control method of claim 19 wherein reduction of the driving torque does not occur when the detected traveling speed is less than a predetermined value.

22. The turning control method of claim 19 wherein reduction of the driving torque of the vehicle engine does not occur when the calculated target lateral acceleration is greater than a predetermined value.

23. The turning control method of claim 19 further comprising the step of:

(f) detecting lateral acceleration applied to the vehicle, wherein the target driving torque of the vehicle is set according solely to the actual lateral acceleration as a lateral acceleration of the vehicle in place of the target lateral acceleration only upon failure to detect a steering angle in step (a), and the target driving torque of the vehicle is alternatively set according solely to the target lateral acceleration as a lateral acceleration of the vehicle only upon detecting a steering angle in step (a).

24. The turning control method of claim 19 further comprising the steps of:

(f) detecting right and left wheel speeds;

(g) determining a neutral steering angle according to said detected right and left wheel speeds and said detected steering angle; and

(h) detecting actual lateral acceleration applied to the vehicle, wherein the target driving torque of the vehicle is set according to the actual lateral acceleration detected until the neutral steering angle is determined, and the target driving torque of the vehicle is set according to the target lateral acceleration after the neutral steering angle is determined.

25. The turning control method of claim 24 further comprising the step of:

(i) interrupting the determining of the neutral steering angle while the driving torque is being reduced, after determining the neutral steering angle.

26. The turning control method of claim 19 further comprising the steps of:

(f) detecting a slip condition of right and left driving wheels of the vehicle; and

(g) calculating a slip prevention target driving torque of the vehicle engine for slip prevention according to the detected slip condition, wherein driving torque of the vehicle engine is equal to any one of the set target driving torque, according to target lateral acceleration, and the set slip prevention target driving torque.

27. A method of turning control for a vehicle comprising the steps of:

(a) detecting a steering angle of a vehicle steering wheel;

(b) detecting traveling speed of the vehicle;

(c) setting a target lateral acceleration of the vehicle as a lateral acceleration, estimated as traveling on a road having a predetermined friction coefficient according to said steering angle and said vehicle traveling speed detected respectively in steps (a) and (b);

(d) converting said target lateral acceleration set in step (c) to a target longitudinal direction acceleration of the vehicle according to a preset relation using solely said target lateral acceleration as a lateral acceleration of the vehicle only upon detecting a steering angle in step (a);

(e) setting a target driving torque of a vehicle engine according to said target longitudinal direction acceleration converted in step (d); and

(f) controlling driving torque of the vehicle engine equal to said target driving torque set in step (e).

28. The turning control method of claim 27 wherein target lateral acceleration GYO is calculated by the following equation:

##EQU25## wherein l is a wheel base of the vehicle, A is a stability factor, V is the detected vehicle traveling speed, and δ

is the detected steering angle.

29. The turning control method of claim 27 wherein target driving torque is set lower as the set target lateral acceleration increases.

30. The turning control method of claim 27 wherein target driving torque is set lower as detected vehicle speed increases.

31. The turning control method of claim 27 wherein said target driving torque is set according to the calculated target longitudinal direction acceleration and a road-load torque.

32. The turning control method of claim 31 wherein the road-load torque includes a rolling drag component and a cornering drag component of the vehicle.

33. The turning control method of claim 32 wherein the cornering drag component varies with actual lateral acceleration of the vehicle.

34. The turning control method of claim 27 wherein the target driving torque is set according to a deviation between the calculated target longitudinal direction acceleration and an actual longitudinal direction acceleration applied to the vehicle.

35. The turning control method of claim 27 further comprising the step of:

(g) calculating a stability factor of the vehicle according to said detected steering angle and said detected vehicle speed, wherein the target lateral acceleration of the vehicle is calculated according to the stability factor and the target longitudinal direction acceleration of the vehicle is calculated according to the calculated target lateral acceleration.

36. A method of turning control for a vehicle comprising the steps of:

(a) detecting a steering angle of a vehicle steering wheel;

(b) detecting traveling speed of the vehicle;

(c) detecting actual lateral acceleration applied to the vehicle during turning of the vehicle;

(d) setting a target lateral acceleration of the vehicle as a lateral acceleration, estimated as traveling on a road having a predetermined friction coefficient according to said steering angle and said vehicle speed detected respectively in steps (a) and (b);

(e) estimating a friction coefficient of a road surface by comparing the target lateral acceleration set in step (d) with said actual lateral acceleration detected in step (c);

(f) storing a plurality of relations between target lateral acceleration set in step (d) and target driving torque of a vehicle engine relative to the friction coefficient of the road surface;

(g) selecting one of the stored plurality of relations between said target lateral acceleration and said target driving torque of the vehicle engine stored in step (f) corresponding to the friction coefficient of the road surface estimated in step (e);

(h) converting said target lateral acceleration set in step (d) to a target driving torque of the vehicle engine according to the relation selected in step (g) using solely said target lateral acceleration set in step (d) as a lateral acceleration of the vehicle; and

(i) controlling a driving torque of the vehicle engine to said target driving torque set in step (h).