Control method for suspension

• US 6,671,596 B2
• Filed: 12/07/2001
• Issued: 12/30/2003
• Est. Priority Date: 12/27/2000
• Status: Expired due to Fees

• Current Assignee: Honda Giken Kogyo Kabushiki Kaisha (Honda Motor Company)
• Original Assignee: Honda Giken Kogyo Kabushiki Kaisha (Honda Motor Company)
• Inventors: Suto, Shinji, Watanabe, Kazuhisa, Kitazawa, Hirokazu, Kawashima, Mitsunori
• Primary Examiner(s): NGUYEN, TAN QUANG
• Application Number:
  US10/013,118
• Publication Number:
  US 20020116104A1
• Time in Patent Office: 753 Days
• Field of Search: 701/37, 701/38, 280/5.5, 280/5.502, 280/5.506, 280/5.507, 280/5.512, 280/5.513, 280/5.514, 280/5.515
• US Class Current: 701/37
• CPC Class Codes: B60G 7/006 Attaching arms to sprung or unsprung part of vehicle, characterised by comprising attachment means controlled by an external actuator, e.g. a fluid or electrical motor B62D7/146 takes precedence

Abstract

A suspension control method for controlling a suspension which includes respective actuators for left and right wheels of a vehicle, and which can apply forces in the upwards and downwards direction to the left and right vehicle wheels via these actuators. While the vehicle is being driven in a straight line, control is performed by giving priority to ride comfort; and, while the vehicle is being driven around a curve, control is performed by giving priority to roll suppression.

Claims

1. A suspension control method for controlling a suspension which comprises respective actuators for left and right wheels of a vehicle, and which can apply forces in the upwards and downwards direction to said left and right vehicle wheels via these actuators, said method comprising:

if an absolute value of steering angle of the vehicle is not more than a predetermined steering angle, an absolute value of a rate of change of the steering angle is not more than a predetermined rate of change of steering angle, and an absolute value of acceleration of the vehicle in forwards and rearwards direction is not more than a predetermined value of the acceleration, then skyhook control is performed for giving priority to ride comfort;

if an absolute value of the steering angle is not more than the predetermined steering angle, and an absolute value of the acceleration in forwards and rearwards direction is greater than the predetermined value of the acceleration, then pitching suppression control is performed so as to suppress pitching of the vehicle; and

if an absolute value of the steering angle is greater than the predetermined steering angle, or an absolute value of the rate of change of the steering angle is greater than the predetermined rate of change of steering angle, then rolling suppression control is performed so as to suppress rolling of the vehicle;

when the skyhook control or the rolling suppression control is performed, the control is performed by multiplying target values by a gain which is determined based upon a vehicle speed; and

when the pitching suppression control is performed, the control is performed based on target values which are not multiplied by the gain.

2. A suspension control method according to claim 1, wherein the acceleration of said vehicle in the upwards and downwards direction is detected, and, if the value of this upwards and downwards acceleration falls outside a predetermined range of values, and has continued to be outside said predetermined value range for longer than a predetermined time period, then control is performed to suppress vibration of said vehicle based upon the value of said upwards and downwards acceleration which is detected.

3. A suspension control method according to claim 1, wherein the acceleration of said vehicle in the upwards and downwards direction is detected, and, if the value of this upwards and downwards acceleration falls within a predetermined range of values, and has continued to be within said predetermined value range for longer than a predetermined time period, then control is not performed to suppress vibration of said vehicle based upon the value of said upwards and downwards acceleration which is detected.

4. A suspension control method according to claim 1, wherein the acceleration in forwards and rearwards direction is detected by an accelerator pedal sensor.

5. A suspension control method according to claim 1, wherein the acceleration in forwards and rearwards direction is detected by a brake pedal sensor.

6. A suspension control method according to claim 1, wherein

when the skyhook control is performed, the acceleration of said vehicle in the upwards and downwards direction is detected, and, if the value of this upwards and downwards acceleration falls outside a predetermined range of values, and has continued to be outside said predetermined value range for longer than a predetermined time period, then control is performed to suppress vibration of said vehicle based upon the value of said upwards and downwards acceleration which is detected, and

if the value of the upwards and downwards acceleration falls within a predetermined range of values, and has continued to be within said predetermined value range for longer than a predetermined time period, then control is not performed to suppress vibration of said vehicle based upon the value of said upwards and downwards acceleration which is detected.

7. A suspension control method according to claim 1, wherein

the actuators are electromagnetic actuators, and the method further comprising:

a step of, when supplying electrical current to said electromagnetic actuator to generate a desired output, calculating a first duty ratio for said electrical current to be supplied to said electromagnetic actuator corresponding to a target electrical current value for said electrical current;

a step of calculating a second duty ratio for said electrical current to converge the actual electrical current value which flows through said electromagnetic actuator to said target electrical current value by proportional integral and differential control; and

a step of supplying electrical current to said electromagnetic actuator according to a third duty ratio which is obtained by adding together said first duty ratio and said second duty ratio.

8. A suspension control method according to claim 1, wherein

in the rolling suppression control, a difference between amounts of movement of left and right wheels of said vehicle in the upwards and downwards direction is detected, and rate of change of steering angle is detected, and actuators are controlled based upon said vehicle wheel movement amount difference and upon said rate of change of steering angle.

9. A suspension control method according to claim 8, wherein

in the rolling suppression control, a stabilizer is provided which mechanically links together said left and right vehicle wheels, and which generates torque according to the difference between the movement amounts of said left and right vehicle wheels in the upwards and downwards direction with respect to said vehicle body;

and wherein deficiency of force to suppress rolling of said vehicle body is, as required, supplemented by said actuators.

10. A suspension control method according to claim 8, wherein

in the rolling suppression control,

when the roll direction of said vehicle and the steering speed direction are the same, control is performed based upon said vehicle wheel movement amount difference with respect to said vehicle body, and upon said rate of change of steering angle;

when the roll direction of said vehicle and the steering speed direction are not the same, control is performed based upon said vehicle wheel movement amount difference with respect to said vehicle body; and

in the central state when the amount of rolling of said vehicle body is small, without any dependence upon whether or not the roll direction of said vehicle and the steering speed direction are the same, control is performed based upon said vehicle wheel movement amount difference with respect to said vehicle body, and upon said rate of change of steering angle.

11. A suspension control method according to claim 10, wherein when determining said central state, the decision is made utilizing hysteresis.

12. A suspension control method according to claim 1, wherein

in the rolling suppression control, sidewise acceleration of said vehicle body is detected, and said actuator is controlled according to the sidewise acceleration and upon rate of change of steering angle.

13. A suspension control method according to claim 12, wherein

in the rolling suppression control,

when the roll direction of said vehicle and the steering speed direction are the same, control is performed based upon said sidewise acceleration and upon said rate of change of steering angle;

and

when the roll direction of said vehicle and the steering speed direction are not the same, control is performed based upon said sidewise acceleration, while,

in the central state when the amount of rolling of said vehicle body is small, without any dependence upon whether or not the roll direction of said vehicle and the steering direction are the same, control is performed based upon the sidewise acceleration of said vehicle wheels with respect to said vehicle body, and upon said rate of change of steering angle.

14. A suspension control method according to claim 13, wherein when determining said central state, the decision is made utilizing hysteresis.

15. A suspension control method according to claim 1, wherein the predetermined steering angle is 5 degrees, the predetermined rate of change of steering angle is 0.5 radians/sec, and the predetermined acceleration in the forwards and rearwards direction is 2 m/s².