Alignment control unit and control method for an automotive suspension

• US 5,438,515 A
• Filed: 10/13/1993
• Issued: 08/01/1995
• Est. Priority Date: 10/14/1992
• Status: Expired due to Fees

• Current Assignee: Mitsubishi Jidosha Kogyo Kabushiki Kaisha
• Original Assignee: Mitsubishi Jidosha Kogyo Kabushiki Kaisha
• Inventors: Tanaka, Tadao, Harara, Mitsuhiko, Miichi, Yoshiki
• Primary Examiner(s): Teska, Kevin J.
• Assistant Examiner(s): NGUYEN, TAN QUANG
• Application Number:
  US08/134,894
• Time in Patent Office: 657 Days
• Field of Search: 364/424.05, 364/426.04, 364/559, 364/571.02, 364/571.04, 364/571.07, 33/203.18, 33/645, 280/840, 280/707, 280/94, 280/91, 280/661, 180/140, 180/234, 180/79.1
• US Class Current: 701/36
• CPC Class Codes: B60G 17/0152 characterised by the action on a particular type of suspension unit B60G17/01941 takes precedence
• CPC Class Codes: B60G 2200/10 Independent suspensions
• CPC Class Codes: B60G 2200/46 camber angle
• CPC Class Codes: B60G 2200/462 Toe-in/out
• CPC Class Codes: B60G 2202/40 Type of actuator
• CPC Class Codes: B60G 2204/11 Mounting of sensors thereon
• CPC Class Codes: B60G 2206/1116 Actively adjustable during driving
• CPC Class Codes: B60G 2400/104 lateral or transversal with regard to vehicle
• CPC Class Codes: B60G 2400/204 Vehicle speed
• CPC Class Codes: B60G 2400/25 Stroke; Height; Displacement
• CPC Class Codes: B60G 2400/302 Selected gear ratio; Transmission function
• CPC Class Codes: B60G 2800/24 Steering, cornering
• CPC Class Codes: B60G 3/26 Means for maintaining substantially-constant wheel camber during suspension movement ; Means for controlling the variation of the wheel position during suspension movement B60G3/202, B60G3/22, B60G7/003, B60G7/006 take precedence; means for adjusting camber, castor, or toe-in B62D17/00
• CPC Class Codes: B60G 7/003 of adjustable length
• CPC Class Codes: B62D 17/00 Means on vehicles for adjusting camber, castor, or toe-in

Abstract

An alignment control unit and method for an automotive suspension are provided in which a basic control amount is determined in accordance with a detected steering angle, and the alignment is controlled in accordance with a product value obtained by multiplying the determined basic control amount by a control gain. The control gain may be set such that an actual control amount of an actuator is changed to be increased when the detected steering angle exceeds a specified value or may be set in accordance with a detected lateral acceleration such that it increases as the lateral acceleration increases. The toe angle or camber angle of a wheel may be controlled in accordance with the basic control amount.

Claims

1. An automotive suspension alignment control unit for a vehicle for controlling toe angle of a right wheel and a left wheel, respectively, comprising:

first actuator for controlling a toe angle of said right wheel;

second actuator for controlling a toe angle of said left wheel;

a steering angle sensor for detecting a steering angle and a steering direction of the vehicle;

a car speed sensor for detecting car speed of said vehicle; and

a controller including,

basic control amount establishing means for establishing a toe angle correction value for said right and left wheels, respectively, in accordance with said steering angle and the steering direction detected by said steering angle sensor,

a toe angle correction amount establishing means for establishing a toe angle correction amount for said right and left wheels, respectively, in accordance with the car speed detected by said car speed sensor,

control gain setting means for setting a control gain that increases as said steering angle detected by said steering angle sensor increases,

actual control amount establishing means for establishing an actual control amount of said first and second actuators, respectively, by adding said toe angle correction amount and said toe angle correction value, and multiplying by said control gain set by said control gain setting means, and

control means for controlling said first and second actuators in accordance with said actual control amount.

2. The automotive suspension alignment control unit of claim 1, wherein said control gain setting means changes the control gain such that said actual control amount of said first and second actuators increase when the detected steering angle detected by said steering angle sensor exceeds a specified value.

3. The automotive suspension alignment control unit of claim 2, wherein the control gain is set to a fixed value when the detected steering angle is equal to or less than a specified value, said control gain being set to a value which gradually increases from said fixed value as the detected steering angle increases after the detected steering angle exceeds said specified value.

4. The automotive suspension alignment control unit of claim 1, wherein, said basic control amount establishing means establishes said toe angle correction value such that said toe angle of one of said right and left wheels in an outer side of a turning circle of the vehicle increases towards a toe-in direction, and said toe angle of the other wheel increases towards a toe-out direction, in accordance with an increase of said detected steering angle.

5. The automotive suspension alignment control unit of claim 1, wherein, said toe angle correction amount establishing means establishes said toe angle correction amount such that said toe angle of one of said right and left wheels in an outer side of a turning circle of the vehicle increases towards a toe-in direction, and said toe angle of the other wheel increases towards a toe-out direction, in accordance with an increase of said detected car speed.

6. An automotive suspension alignment control unit for a vehicle for controlling camber angle of a right wheel and a left wheel, respectively, comprising:

first actuator for controlling a camber angle of said right wheel;

second actuator for controlling a camber angle of said left wheel;

a steering angle sensor for detecting a steering angle and a steering direction of the vehicle;

a car speed sensor for detecting car speed of said vehicle; and

a controller including,

basic control amount establishing means for establishing a camber angle correction value for said right and left wheels, respectively, in accordance with said steering angle and said steering direction detected by said steering angle sensor,

a camber angle correction amount establishing means for establishing a camber angle correction amount for said right and left wheels, respectively, in accordance with the car speed detected by said car speed sensor,

control gain setting means for setting a control gain that increases as said steering angle detected by said steering angle sensor increases,

actual control amount establishing means for establishing an actual control amount of said first and second actuators, respectively, by adding said camber angle correction amount and said camber angle correction value, and multiplying by said control gain set by said control gain setting means, and

control means for controlling said first and second actuators in accordance with said actual control amount.

7. The automotive suspension alignment control unit of claim 6, wherein said control gain setting means changes the control gain such that said actual control amount of said first and second actuators increase when the detected steering angle detected by said steering angle sensor exceeds a specified value.

8. The automotive suspension alignment control unit of claim 7, wherein the control gain is set to a fixed value when the detected steering angle is equal to or less than a specified value, the control gain being set to a value which gradually increases from said fixed value as the detected steering angle increases after the detected steering angle exceeds said specified value.

9. The automotive suspension alignment control unit of claim 6, wherein, said basic control amount establishing means establishes said camber angle correction value such that said camber angle of one of said right and left wheels in an outer side of a turning circle of the vehicle increases towards a negative-camber direction, and said camber angle of the other wheel increases towards a positive-camber direction, in accordance with an increase of said detected steering angle.

10. The automotive suspension alignment control unit of claim 6, wherein, said camber angle correction amount establishing means establishes said camber angle correction amount such that said camber angle of one of said right and left wheels in an outer side of a turning circle of the vehicle increases towards a negative-camber direction, and said toe angle of the other wheel increases towards a positive-camber direction, in accordance with an increase of said detected car speed.

11. An automotive suspension alignment control unit for a vehicle for controlling toe angle of a right wheel and a left wheel, respectively, comprising:

first actuator for controlling a toe angle of said right wheel;

second actuator for controlling a toe angle of said left wheel;

a steering angle sensor for detecting a steering angle and a steering direction of the vehicle;

a car speed sensor for detecting car speed;

a lateral acceleration sensor for detecting lateral acceleration acting on the vehicle in a lateral direction thereof; and

a controller including,

basic control amount establishing means for establishing a toe angle correction value for said right and left wheels, respectively, in accordance with said steering angle and said steering direction detected by said steering angle sensor,

a toe angle correction amount establishing means for establishing a toe angle correction amount for said right and left wheels, respectively, in accordance with the car speed detected by said car speed sensor,

control gain setting means for setting a control gain in accordance with said detected lateral acceleration;

actual control amount establishing means for establishing an actual control amount of said first and second actuators based on said basic control amount and said control gain; and

control means for controlling said first and second actuators in accordance with said actual control amount.

12. The alignment control unit according to claim 11, wherein said controller controls toe angles of the associated wheels in accordance with the set alignment control amount.

13. The automotive suspension alignment control unit of claim 11, wherein said control gain is set to a value which increases as the detected lateral acceleration increases.

14. An automotive suspension alignment control unit for a vehicle for controlling camber angle of a right wheel and a left wheel, respectively, comprising:

first actuator for controlling a camber angle of said right wheel;

second actuator for controlling a camber angle of said left wheel;

a steering angle sensor for detecting a steering angle and a steering direction of the vehicle;

a car speed sensor for detecting car speed,

a lateral acceleration sensor for detecting lateral acceleration acting on the vehicle in a lateral direction thereof; and

a controller including,

basic control amount establishing means for establishing a camber angle correction value for said right and left wheels, respectively, in accordance with said steering angle and said steering direction detected by said steering angle sensor,

a camber angle correction amount establishing means for establishing a camber angle correction amount for said right and left wheels, respectively, in accordance with the car speed detected by said car speed sensor,

control gain setting means for setting a control gain in accordance with said detected lateral acceleration;

actual control amount establishing means for establishing an actual control amount of said first and second actuators based on said basic control amount and said control gain; and

control means for controlling said first and second actuators in accordance with said actual control amount.

15. The automotive suspension alignment control unit of claim 14, wherein said control gain is set to a value which increases as the detected lateral acceleration increases.

16. An automotive suspension alignment control method for controlling toe angle of a right wheel and a left wheel of a vehicle, comprising the steps of:

detecting a steering angle and a steering direction;

determining a toe angle correction value for said right wheel and said left wheel in accordance with the detected steering angle and the steering direction;

detecting car speed;

setting a toe angle correction amount for said right wheel and said left wheel in accordance with the detected car speed;

determining a control gain in accordance with the detected steering angle such that the control gain is set to have a value which increases as the steering angle increases;

determining an actual control amount of said toe angle by adding said toe angle control correction value and said toe angle correction amount, and multiplying by said control gain; and

controlling said toe angle of said right and said left wheel in accordance with said actual control amount.

17. The automotive suspension alignment control method of claim 16, wherein said control gain is set such that the actual control amount increases when the detected steering angle exceeds a specified value.

18. The alignment control method of claim 17, wherein said control gain is set to a fixed value when the detected said steering angle is equal to or less than said specified value and gradually increases from said fixed value as the detected said steering angle exceeds said specified value.

19. The alignment control method of claim 17, wherein said control gain is set such that said actual control amount increases when the detected steering angle exceeds a specified value.

20. The alignment control method of claim 19, wherein said control gain is set to a fixed value when the detected said steering angle is equal to or less than said specified value and gradually increases from said fixed value as the detected said steering angle exceeds said specified value.

21. The automotive suspension alignment control method of claim 16, wherein said step for determining a toe angle correction value comprises the substep of,

increasing said toe angle of one of said right and left wheels in an outer side of a turning circle of the vehicle towards a toe-in direction and increasing said toe angle of the other wheel towards a toe-out direction, in accordance with an increase of said detected steering angle.

22. The automotive suspension alignment control method of claim 16, wherein said step for setting a toe angle correction amount comprises the substep of,

increasing said toe angle of one of said right and left wheels in an outer side of a turning circle of the vehicle towards a toe-in direction and increasing said toe angle of the other wheel towards a toe-out direction, in accordance with said detected car speed.

23. An automotive suspension alignment control method for controlling toe angle of a right wheel and a left wheel of a vehicle, comprising the steps of:

detecting a steering angle and a steering direction;

determining a camber angle correction value for said right wheel and said left wheel in accordance with the detected steering angle and the steering direction;

detecting car speed;

setting a camber angle correction amount for said right wheel and said left wheel in accordance with the detected car speed;

determining a control gain having a value which is set to a fixed value when the detected said steering angle is equal to or less than a specified value and which gradually increases from said fixed value as the detected said steering angle exceeds said specified value;

determining an actual control amount of said camber angle by adding said camber angle control correction value and said camber angle correction amount, and multiplying by said control gain; and

controlling said toe angle of said right and said left wheel in accordance with said actual control amount.

24. The automotive suspension alignment control method of claim 23, wherein said step for determining a camber angle correction value comprises the substep of,

increasing said camber angle of one of said right and left wheels in an outer side of a turning circle of the vehicle towards a negative-camber direction and increasing said toe angle of the other wheel towards a positive-camber direction, in accordance with an increase of said detected steering angle.

25. The automotive suspension alignment control method of claim 23, wherein said step for setting a camber angle correction amount comprises the substep of,

increasing said camber angle of one of said right and left wheels in an outer side of a turning circle of the vehicle towards a negative-camber direction and increasing said toe angle of the other wheel towards a positive-camber direction, in accordance with an increase of said detected car speed.

26. An automotive suspension alignment control method for controlling toe angle of a right wheel and a left wheel of a vehicle, comprising the steps of:

detecting a steering angle and a steering direction;

determining a toe angle correction value for said right wheel and said left wheel in accordance with the detected steering angle and the steering direction;

detecting car speed;

setting a toe angle correction amount for said right wheel and said left wheel in accordance with the detected car speed;

detecting lateral acceleration acting on the vehicle in a lateral direction of the vehicle;

determining a control gain in accordance with the detected lateral acceleration;

determining an actual control amount of said toe angle by adding said toe angle control correction value and said toe angle correction amount, and multiplying by said control gain; and

controlling said toe angle of said right and said left wheel in accordance with said actual control amount.

27. The alignment control method of claim 26, wherein said control gain is set to a value which increases as the lateral acceleration increases.

28. An automotive suspension alignment control method for controlling camber angle of a right wheel and a left wheel of a vehicle, comprising the steps of:

detecting a steering angle and a steering direction;

determining a camber angle correction value for said right wheel and said left wheel in accordance with the detected steering angle and the steering direction;

detecting car speed;

setting a camber angle correction amount for said right wheel and said left wheel in accordance with the detected car speed;

detecting lateral acceleration acting on the vehicle in a lateral direction of the vehicle;

determining a control gain in accordance with the detected lateral acceleration such that the control gain is set to a value which increases as the lateral acceleration increases;

determining an actual control amount of said camber angle by adding said toe angle control correction value and said camber angle correction amount, and multiplying by said control gain; and

controlling said camber angle of said right and said left wheels in accordance with said actual control amount.

29. The alignment control method of claim 28, wherein said control gain is set to a value which increases as the lateral acceleration increases.

30. The alignment control method of claim 29, wherein said control gain is set to a value which increases as the lateral acceleration increases.

31. An automotive suspension alignment control unit for a vehicle for controlling a toe angle and a camber angle of a right wheel and a left wheel, respectively, comprising:

first actuator for controlling a toe angle and a camber angle of said right wheel;

second actuator for controlling a toe angle and a camber angle of said left wheel;

a steering angle sensor for detecting a steering angle and a steering direction of the vehicle;

a car speed sensor for detecting car speed of said vehicle; and

a controller including,

basic control amount establishing means for establishing a toe angle correction value and a camber angle correction value for said right and left wheels, respectively, in accordance with said steering angle and said steering direction detected by said steering angle sensor,

correction amount establishing means for establishing a toe angle correction amount and a camber angle correction amount for said right and left wheels, respectively, in accordance with the car speed detected by said car speed sensor,

control gain setting means for setting a control gain that increases as said steering angle detected by said steering angle sensor increases,

actual control amount establishing means for establishing an actual toe control amount of said first and second actuators, respectively, by adding said toe angle correction amount and said toe angle correction value, and multiplying by said control gain set by said control gain setting means, and an actual camber control amount of said first and second actuators, respectively, by adding said camber angle correction amount and said camber angle correction value, and multiplying by said control gain set by said control gain setting means, and

control means for controlling said first and second actuators in accordance with said actual toe control amount and said actual camber control amount.

32. The automotive suspension alignment control unit of claim 31, wherein said control gain is set such that the actual control amount increases when the detected steering angle exceeds a specified value.

33. The alignment control unit of claim 32, wherein said control gain is set to a fixed value when the detected said steering angle is equal to or less than said specified value and gradually increases from said fixed value as the detected said steering angle exceeds said specified value.

34. An automotive suspension alignment control method for controlling toe angle and camber angle of a right wheel and a left wheel of a vehicle, comprising the steps of:

detecting a steering angle and a steering direction;

determining a toe angle correction value and a camber angle correction value for said right wheel and said left wheel in accordance with the detected steering angle and the steering direction;

detecting car speed;

setting a toe angle correction amount and a camber angle correction amount for said right wheel and said left wheel in accordance with the detected car speed;

determining a control gain in accordance with the detected steering angle such that the control gain is set to a value which increases as the steering angle increases;

determining an actual toe angle control amount by adding said toe angle control correction value and said toe angle correction amount, and multiplying by said control gain, and an actual camber angle control amount by adding said camber angle control correction value and said camber angle correction amount; and

controlling said toe angle and said camber angle of said right and said left wheels in accordance with said actual toe control amount and said actual camber control amount.

35. The alignment control method of claim 34, wherein said control gain is set such that said actual control amount increases when the detected steering angle exceeds a specified value.

36. The alignment control method of claim 35, wherein said control gain is set to a fixed value when the detected said steering angle is equal to or less than said specified value and gradually increases from said fixed value as the detected said steering angle exceeds said specified value.

37. An automotive suspension alignment control unit for a vehicle for controlling toe angle and camber angle of a right wheel and a left wheel, respectively, comprising:

first actuator for controlling a toe angle and a camber angle of said right wheel;

second actuator for controlling a toe angle and a camber angle of said left wheel;

a steering angle sensor for detecting a steering angle and a steering direction of the vehicle;

a car speed sensor for detecting car speed of said vehicle; and

a controller including,

basic control amount establishing means for establishing a toe angle correction value and a camber angle correction value for said right and left wheels, respectively, in accordance with said steering angle and said steering direction detected by said steering angle sensor,

correction amount establishing means for establishing a toe angle correction amount and a camber angle correction amount for said right and left wheels, respectively, in accordance with the car speed detected by said car speed sensor,

a lateral acceleration sensor for detecting lateral acceleration acting on the vehicle in a lateral direction thereof;

control gain setting means for setting a control gain in accordance with the detected lateral acceleration such that the control gain is set to a value which increases as the lateral acceleration increases;

actual control amount establishing means for establishing an actual toe control amount of said first and second actuators, respectively, by adding said toe angle correction amount and said toe angle correction value, and multiplying by said control gain set by said control gain setting means, and an actual camber control amount of said first and second actuators, respectively, by adding said camber angle correction amount and said camber angle correction value, and multiplying by said control gain set by said control gain setting means, and

control means for controlling said first and second actuators in accordance with said actual toe control amount and said actual camber control amount.

38. An automotive suspension alignment control method for controlling toe angle and camber angle of a right wheel and a left wheel of a vehicle, comprising the steps of:

detecting a steering angle and a steering direction;

determining a toe angle correction value and a camber angle correction value for said right wheel and said left wheel in accordance with the detected steering angle and the steering direction;

detecting car speed;

setting a toe angle correction amount and a camber angle correction amount for said right wheel and said left wheel in accordance with the detected car speed;

detecting lateral acceleration acting on the vehicle in a lateral direction of the vehicle;

determining a control gain in accordance with the detected lateral acceleration;

determining an actual toe angle control amount by adding said toe angle control correction value and said toe angle correction amount, and multiplying by said control gain, and an actual camber angle control amount by adding said camber angle control correction value and said camber angle correction amount; and

controlling said toe angle and said camber angle of said right and said left wheel in accordance with said actual toe control amount and said actual camber control amount.

39. The alignment control method of claim 38, wherein said control gain is set to a value which increases as the lateral acceleration increases.