ACTIVE SUSPENSION AND METHOD FOR CONTROLLING VEHICLE ATTITUDE CHANGE

• US 20090037051A1
• Filed: 07/30/2008
• Published: 02/05/2009
• Est. Priority Date: 08/03/2007
• Status: Abandoned Application

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Ono, Hitoshi, SHIMIZU, Naoshige
• Application Number:
  US12/182,733
• Publication Number:
  US 20090037051A1
• Time in Patent Office: Days
• US Class Current: 701/38
• CPC Class Codes: B60G 17/0162 mainly during a motion involving steering operation, e.g. cornering, overtaking B60G17/0164 takes precedence
• CPC Class Codes: B60G 17/0164 mainly during accelerating or braking
• CPC Class Codes: B60G 17/018 characterised by the use of a specific signal treatment or control method
• CPC Class Codes: B60G 17/04 fluid spring characteristics
• CPC Class Codes: B60G 17/056 Regulating distributors or valves for hydropneumatic systemsB60G17/044 - B60G17/048, B60G17/0416 take precedence; Fluid interconnection systems to control vehicle inclination B60G21/06, B60G21/10; valves per se F16K
• CPC Class Codes: B60G 2202/12 Wound spring
• CPC Class Codes: B60G 2202/413 Hydraulic actuator
• CPC Class Codes: B60G 2400/05 Attitude
• CPC Class Codes: B60G 2400/0511 Roll angle
• CPC Class Codes: B60G 2400/0512 Pitch angle
• CPC Class Codes: B60G 2400/0531 Roll acceleration
• CPC Class Codes: B60G 2400/0532 Pitch acceleration
• CPC Class Codes: B60G 2400/0533 Yaw acceleration
• CPC Class Codes: B60G 2400/102 vertical
• CPC Class Codes: B60G 2400/104 lateral or transversal with regard to vehicle
• CPC Class Codes: B60G 2400/106 longitudinal with regard to vehicle, e.g. braking
• CPC Class Codes: B60G 2400/252 vertical
• CPC Class Codes: B60G 2400/302 Selected gear ratio; Transmission function
• CPC Class Codes: B60G 2400/33 Throttle position
• CPC Class Codes: B60G 2400/34 Accelerator pedal position
• CPC Class Codes: B60G 2400/41 : Steering angle
• CPC Class Codes: B60G 2400/62 : Seat occupation; Passenger presence
• CPC Class Codes: B60G 2400/63 : Location of the center of gravity
• CPC Class Codes: B60G 2500/104 : continuous
• CPC Class Codes: B60G 2500/203 : Distributor valve units comprising several elements, e.g. valves, pump or accumulators
• CPC Class Codes: B60G 2600/02 : Retarders, delaying means, dead zones, threshold values, cut-off frequency, timer interruption
• CPC Class Codes: B60G 2600/182 : Active control means
• CPC Class Codes: B60G 2600/1873 : Model Following
• CPC Class Codes: B60G 2600/26 : Electromagnets; Solenoids
• CPC Class Codes: B60G 2600/70 : Computer memory; Data storage, e.g. maps for adaptive control
• CPC Class Codes: B60G 2800/012 : Rolling condition
• CPC Class Codes: B60G 2800/014 : Pitch; Nose dive
• CPC Class Codes: B60G 2800/70 : Estimating or calculating vehicle parameters or state variables
• CPC Class Codes: B60G 2800/912 : Attitude Control; levelling control

Abstract

An active suspension system has a plurality of actuators which are respectively installed between a wheel and a vehicle body and individually produce a control force, and a control unit which controls an attitude change of a vehicle by controlling the each control force of the plurality of actuators. The control unit sets first and second virtual control lines which extend along a front-and-rear direction of the vehicle and a width direction of the vehicle respectively and are changed so that the first and second virtual control lines follow expected pitching and rolling that would occur to the vehicle, and then controls the vehicle attitude so that the vehicle attitude is brought closer to the virtual control line.

Claims

1. An active suspension system comprising:

a plurality of actuators which are respectively installed between a wheel and a vehicle body and individually produce a control force; and

a control unit which controls an attitude change of a vehicle by controlling the each control force of the actuators, and

the control unit setting a virtual control line that is changed according to a vehicle driving condition and controlling the vehicle attitude in a direction in which an inclination of the vehicle with respect to the virtual control line becomes small.

2. The active suspension system as claimed in claim 1, wherein:

the control unit sets, as the virtual control line, at least one virtual control line of a first virtual control line that extends along a front-and-rear direction of the vehicle and a second virtual control line that extends along a width direction of the vehicle, and controls the vehicle attitude to bring the vehicle attitude closer to the virtual control line.

3. The active suspension system as claimed in claim 1, wherein:

the virtual control line is changed on the basis of an expected vehicle attitude.

4. The active suspension system as claimed in claim 3, wherein:

the virtual control line is changed by moving the virtual control line with a predetermined speed.

5. The active suspension system as claimed in claim 3, wherein:

the control unit sets a reference virtual control line as a reference position of the virtual control line, and

when judged that the expected vehicle attitude is within a predetermined range, the virtual control line is set to the position of the reference virtual control line or the change of the virtual control line is halted.

6. The active suspension system as claimed in claim 3, wherein:

the control unit sets, as the virtual control line, a first virtual control line that extends along a front-and-rear direction of the vehicle, and wherein

the control unit has

an expected pitch angle calculating section which calculates an expected pitch angle of pitching that would occur to the vehicle, as information of the expected vehicle attitude; and

a first virtual control line changing section which changes an inclination, viewed from a side of the vehicle, of the first virtual control line to become closer to the expected pitch angle calculated by the expected pitch angle calculating section.

7. The active suspension system as claimed in claim 3, wherein:

the control unit sets, as the virtual control line, a second virtual control line that extends along a width direction of the vehicle, and wherein

the control unit has

an expected roll angle calculating section which calculates an expected roll angle of rolling that would occur to the vehicle, as information of the expected vehicle attitude; and

a second virtual control line changing section which changes an inclination, viewed from a front-and-rear direction of the vehicle, of the second virtual control line to become closer to the expected roll is angle calculated by the expected roll angle calculating section.

8. A method for suppressing an attitude change of a vehicle, wherein the vehicle includes a plurality of actuators respectively installed between a wheel and a vehicle body and individually producing a control force, the method comprising:

setting a virtual control line that is changed according to a vehicle driving condition; and

controlling the each control force of the actuators to bring the vehicle attitude closer to the virtual control line.

9. The method for suppressing the attitude change of the vehicle as claimed in claim 8, wherein:

the virtual control line is at least one virtual control line of a first virtual control line that extends along a front-and-rear direction of the vehicle and a second virtual control line that extends along a width direction of the vehicle.

10. The method for suppressing the attitude change of the vehicle as claimed in claim 9, wherein:

the first virtual control line is changed so that an inclination of the first virtual control line becomes closer to an expected pitch angle of pitching that would occur to the vehicle, and

the second virtual control line is changed so that an inclination of the second virtual control line becomes closer to an expected roll angle of rolling that would occur to the vehicle.

11. An active suspension system comprising:

a plurality of actuators which are respectively installed between a wheel and a vehicle body and individually produce a control force; and

control means for controlling an attitude change of a vehicle by controlling the each control force of the actuators, and

the control means having;

setting means for setting a virtual control line that is changed according to a vehicle driving condition; and

control means for controlling the vehicle attitude in a direction in which an inclination of the vehicle with respect to the virtual control line becomes small.