Damping force control device and method

• US 6,366,841 B1
• Filed: 04/18/2000
• Issued: 04/02/2002
• Est. Priority Date: 04/20/1999
• Status: Expired due to Fees

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Ohsaku, Satoru
• Primary Examiner(s): ARTHUR JEANGLAUDE, GERTRUDE
• Application Number:
  US09/551,647
• Time in Patent Office: 714 Days
• Field of Search: 701/37, 701/38, 701/39, 280/5.5, 280/5.507, 280/5.515, 248/550
• US Class Current: 701/37
• 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 2400/0511 Roll angle
• CPC Class Codes: B60G 2400/0512 Pitch angle
• CPC Class Codes: B60G 2400/102 vertical
• CPC Class Codes: B60G 2400/252 vertical
• CPC Class Codes: B60G 2400/52 in tyre
• CPC Class Codes: B60G 2400/94 Deformation of a vehicle part
• CPC Class Codes: B60G 2800/012 Rolling condition
• CPC Class Codes: B60G 2800/014 Pitch; Nose dive

Abstract

A damping force control device and method controls damping forces of dampers at locations of respective wheels. A first target damping force that inhibits vibrations of a vehicle body in the heave direction is calculated for each of the wheels, based on a single wheel model of the vehicle which employs the skyhook theory. A second target damping force that inhibits vibrations of the vehicle body in the pitch direction is calculated for each of the wheels, based on a model of front and rear wheels of the vehicle. A third target damping force that inhibits vibrations of the vehicle body in the roll direction is calculated for each of the wheels, based on a model of left and right wheels of the vehicle. One of the first through third target damping forces that has the greatest absolute value is selected for each of the wheels. The damping force exerted by the damper at the location of each wheel is set to the selected target damping force. Such a damping force control device inhibits the vehicle from making pitch or roll movements without damaging the control performance for attenuating vertical vibrations of the vehicle body.

Claims

1. A damping force control device for controlling damping forces of dampers disposed between a vehicle body and respective wheels of a vehicle, comprising a controller that:

calculates, for each of the wheels, a first target damping force that inhibits vibrations of the vehicle body in a heave direction, based on a single wheel model of the vehicle;

calculates, for each of the wheels, a second target damping force that inhibits vibrations of the vehicle body in a pitch direction, based on a model of front and rear wheels of the vehicle;

determines an ultimate target damping force for each of the wheels, based on the calculated first and second target damping forces; and

outputs a control signal corresponding to the determined ultimate target damping force to each of the dampers such that a damping force exerted by each of the dampers is set to the determined ultimate target damping force.

2. The damping force control device according to claim 1, wherein the controller:

calculates the first target damping force in accordance with a vertical kinetic state quantity of the vehicle body; and

calculates the second target damping force in accordance with a kinetic state quantity of the vehicle body in the pitch direction.

3. The damping force control device according to claim 1, wherein the controller:

determines the ultimate target damping force by selecting the greater one of the calculated first and second target damping forces for each of the wheels.

4. The damping force control device according to claim 3, wherein the controller:

calculates the first target damping force in accordance with a vertical kinetic state quantity of the vehicle body; and

calculates the second target damping force in accordance with a kinetic state quantity of the vehicle body in the pitch direction.

5. The damping force control device according to claim 1, wherein the controller:

judges a relation in degree of magnitude of absolute values of the first and second target damping forces;

weights the target damping force of the greater absolute value with a greater weight; and

summatively synthesizes the respectively weighted first and second target damping forces, and thereby determines the ultimate target damping force.

6. A damping force control device for controlling damping forces of dampers disposed between a vehicle body and respective wheels of a vehicle, comprising a controller that:

calculates, for each of the wheels, a first target damping force that inhibits vibrations of the vehicle body in a heave direction, based on a single wheel model of the vehicle;

calculates, for each of the wheels, a second target damping force that inhibits vibrations of the vehicle body in a roll direction, based on a model of left and right wheels of the vehicle;

determines an ultimate target damping force for each of the wheels, based on the calculated first and second target damping forces; and

outputs a control signal corresponding to the determined ultimate target damping force to each of the dampers such that a damping force exerted by each of the dampers is set to the determined ultimate target damping force.

7. The damping force control device according to claim 6, wherein the controller:

calculates the first target damping force in accordance with a vertical kinetic state quantity of the vehicle body; and

calculates the second target damping force in accordance with a kinetic state quantity of the vehicle body in the roll direction.

8. The damping force control device according to claim 6, wherein the controller:

determines the ultimate target damping force by selecting the greater one of the calculated first and second target damping forces for each of the wheels; and

outputs the selected control signal to each of the dampers such that the damping force exerted by each of the dampers is set to the selected target damping force.

9. The damping force control device according to claim 8, wherein the controller:

calculates the first target damping force in accordance with a vertical kinetic state quantity of the vehicle body; and

calculates the second target damping force in accordance with a kinetic state quantity of the vehicle body in the roll direction.

10. The damping force control device according to claim 6, wherein the controller:

judges a relation in degree of magnitude of absolute values of the first and second target damping forces;

weights the target damping force of the greater absolute value with a greater weight; and

summatively synthesizes the respectively weighted first and second target damping forces, and thereby determines the ultimate target damping force.

11. A damping force control device for controlling damping forces of dampers disposed between a vehicle body and respective wheels of a vehicle, comprising a controller that:

calculates, for each of the wheels, a first target damping force that inhibits vibrations of the vehicle body in a heave direction, based on a single wheel model of the vehicle;

calculates, for each of the wheels, a second target damping force that inhibits vibrations of the vehicle body in a pitch direction, based on a model of front and rear wheels of the vehicle;

calculates, for each of the wheels, a third target damping force that inhibits vibrations of the vehicle body in a roll direction, based on a model of left and right wheels of the vehicle;

determines an ultimate target damping force for each of the wheels, based on the calculated first, second and third target damping forces;

outputs a control signal corresponding to the determined ultimate target damping force to each of the dampers such that a damping force exerted by each of the dampers is set to the determined ultimate target damping force.

12. The damping force control device according to claim 11, wherein the controller:

calculates the first target damping force in accordance with a vertical kinetic state quantity of the vehicle body;

calculates the second target damping force in accordance with a kinetic state quantity of the vehicle body in the pitch direction; and

calculates the third target damping force in accordance with a kinetic state quantity of the vehicle body in the roll direction.

13. The damping force control device according to claim 11, wherein the controller:

selects the greatest one of the calculated first, second and third target damping forces for each of the wheels; and

outputs a control signal corresponding to the selected target damping force to each of the dampers and performs control such that the damping force exerted by each of the dampers is set to the selected target damping force.

14. The damping force control device according to claim 13, wherein the controller:

calculates the first target damping force in accordance with a vertical kinetic state quantity of the vehicle body;

calculates the second target damping force in accordance with a kinetic state quantity of the vehicle body in the pitch direction; and

calculates the third target damping force in accordance with a kinetic state quantity of the vehicle body in the roll direction.

15. The damping force control device according to claim 11, wherein the controller:

judges a relation in degree of magnitude of absolute values of the first, second and third target damping forces;

increases weights with which the target damping forces are weighted as the absolute values increase; and

summatively synthesizes the respectively weighted first, second and third target damping forces, and thereby determines the ultimate target damping force.

16. The damping force control device according to claim 11, wherein the controller:

judges a relation in degree of magnitude of absolute values of the first, second and third target damping forces;

chooses the target damping forces of the greatest two absolute values; and

summatively synthesizes the chosen target damping forces, and thereby determines the ultimate target damping force.

17. The damping force control device according to claim 11, wherein the controller:

judges a relation in degree of magnitude of absolute values of the first, second and third target damping forces;

chooses the target damping forces of the greatest two absolute values;

weights one of the chosen target damping forces that has the greater absolute value with a greater weight; and

summatively synthesizes the chosen target damping forces, and thereby determines the ultimate target damping force.

18. A damping force control method for controlling damping forces of dampers disposed between a vehicle body and respective wheels of a vehicle, comprising:

calculating, for each of the wheels, a first target damping force that inhibits vibrations of the vehicle body in a heave direction, based on a single wheel model of the vehicle;

calculating, for each of the wheels, a second target damping force that inhibits vibrations of the vehicle body in a pitch direction, based on a model of front and rear wheels of the vehicle;

determining an ultimate target damping force for each of the wheels, based on the calculated first and second target damping forces; and

outputting a control signal corresponding to the determined ultimate target damping force to each of the dampers such that a damping force exerted by each of the dampers is set to the determined ultimate target damping force.

19. A damping force control method for controlling damping forces of dampers disposed between a vehicle body and respective wheels of a vehicle, comprising:

calculating, for each of the wheels, a first target damping force that inhibits vibrations of the vehicle body in a heave direction, based on a single wheel model of the vehicle;

calculating, for each of the wheels, a second target damping force that inhibits vibrations of the vehicle body in a roll direction, based on a model of left and right wheels of the vehicle;

determining an ultimate target damping force for each of the wheels, based on the calculated first and second target damping forces; and

outputting a control signal corresponding to the determined ultimate target damping force to each of the dampers such that a damping force exerted by each of the dampers is set to the determined ultimate target damping force.

20. A damping force control method for controlling damping forces of dampers disposed between a vehicle body and respective wheels of a vehicle, comprising:

calculating, for each of the wheels, a first target damping force that inhibits vibrations of the vehicle body in a heave direction, based on a single wheel model of the vehicle;

calculating, for each of the wheels, a second target damping force that inhibits vibrations of the vehicle body in a pitch direction, based on a model of front and rear wheels of the vehicle;

calculating, for each of the wheels, a third target damping force that inhibits vibrations of the vehicle body in a roll direction, based on a model of left and right wheels of the vehicle;

determining an ultimate target damping force for each of the wheels, based on the calculated first, second and third target damping forces; and

outputting a control signal corresponding to the determined ultimate target damping force to each of the dampers such that a damping force exerted by each of the dampers is set to the determined ultimate target damping force.