Linear control of an automobile suspension

1. A vehicle suspension system comprising:

a cylinder;

a rod inserted within said cylinder;

a piston coupled to said rod;

a piston valve coupled to said piston, wherein said piston valve has an input piston current (i p );

a base coupled to said cylinder;

a base valve coupled to said base, wherein said base valve has an input base current (i b ); and

a controller coupled to said piston valve and said base valve, said controller adapted to generate said input piston current and said input base current based on a generated virtual current (i v );

wherein said input piston current and said input base current are generated from said virtual current based substantially on the following equation:

i

b

=

{

i

-

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i

v

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(

i

+

-

i

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i

v

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0

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i

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.

2. The vehicle suspension system of claim 1 , wherein said piston valve and said base valve are current controlled continually variable semi-active valves.

3. The vehicle suspension system of claim 1 , further comprising a pump coupled to said cylinder.

4. The vehicle suspension system of claim 1 , further comprising a piston check valve coupled to said piston and a base check valve coupled to said base.

5. The vehicle suspension system of claim 1 , wherein said virtual current is generated based on a vertical acceleration of a vehicle and a wheel.

6. The vehicle suspension system of claim 1 , wherein said virtual current is generated based on a linear model.

7. A method of controlling an active shock absorber of a vehicle, said shock absorber having a current controlled piston valve and a current controlled base valve, said method comprising:

receiving a vertical acceleration of the vehicle;

calculating a virtual current based on the acceleration; and

calculating a piston valve current (i p ) and a base valve current (i b ) based on the virtual current (i v );

wherein said piston valve current and said base valve current are calculated using substantially the following equation:

i

b

=

{

i

-

-

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v

⁡

(

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+

-

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i

v

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.

8. The method of claim 7 , wherein said virtual current is calculated based on a linear model.

9. The method of claim 7 , wherein said virtual current is calculated by a μ-synthesis designed controller.

10. The method of claim 7 , said controller is further adapted to calculate the virtual current based on a vertical wheel acceleration.

11. A controller for controlling an active shock absorber of a vehicle, said shock absorber having a current controlled piston valve and a current controlled base valve, said controller adapted to:

receive a vertical acceleration of the vehicle;

calculate a virtual current based on the acceleration; and

calculate a piston valve current (i p ) and a base valve current (i b ) based on the virtual current (i v );

wherein said piston valve current and said base valve current are calculated using substantially the following equation:

i

b

=

{

i

-

-

i

v

⁡

(

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+

-

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v

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0

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12. The controller of claim 11 , wherein said virtual current is calculated based on a linear model.

13. The controller of claim 11 , comprising a μ-synthesis design.

14. The controller of claim 11 , said controller is further adapted to calculate the virtual current based on a vertical wheel acceleration.