Seamless control of spring stiffness in a liquid spring system

Abstract

A vibration control system for a structure having a first structural member and a second structural member. The vibration control system having a liquid spring operably interposed between the first structural member and the second structural member. The liquid spring uses a compressible liquid to seamlessly generate spring and/or damping forces in the suspension system in response to relative displacement between the first structural member and the second structural member. A second volume of compressible liquid is located in a second chamber. The second volume is removably connected to the liquid spring by a fluid passage. A valve is coupled to the fluid passage, the valve selectively operable to place the second volume in communication with the liquid spring. A controller is electrically coupled to the valve. The controller emitting a control signal to control the valve.

1 . A suspension control system for a vehicle having a frame and a plurality of wheels, the suspension control system comprising:
 a plurality of liquid springs, wherein one of the plurality of liquid springs is operably interposed between the frame and a respective one of the plurality of wheels and uses a compressible liquid to generate spring forces in response to relative displacement between the frame and the respective one of the plurality of wheels;   a plurality of second volumes of compressible liquid, the plurality of second volumes in at least one second chamber and removably connected to a respective one of the plurality of liquid springs by a respective fluid passage;   a plurality of valves, each of the plurality of valves coupled to the respective fluid passage and selectively operable to place a respective one of the plurality of second volumes in communication with a respective one of the plurality of liquid springs;   a turning motion sensor; and   a controller electrically coupled to the turning motion sensor and to the plurality of valves, the controller receiving signals from the turning motion sensor and emitting a control signal to control the plurality of valves;   wherein the controller alters the control signal to change at least one of the group consisting of a pressure, a volume, and a rate of flow of compressible liquid in at least of the plurality of liquid springs.   
   
   
       2 . The suspension control system of  claim 1 , wherein the plurality of second volumes are combined in one or more second chambers. 
   
   
       3 . The suspension control system of  claim 1  further comprising a vehicle speed sensor electrically coupled to the controller, wherein roll control by the controller is only adjusted for certain predetermined vehicle speeds. 
   
   
       4 . The suspension control system of  claim 1 , wherein the turning motion sensor is a steering position sensor and the controller adjusts at least one of the plurality of valves to increase spring stiffness during a turn. 
   
   
       5 . The suspension control system of  claim 1 , wherein the turning motion sensor is a tilt sensor and the controller adjusts at least one of the plurality of valves to increase spring stiffness to counteract tilting of the vehicle. 
   
   
       6 . The suspension control system of  claim 1 , wherein the turning motion sensor is a tilt sensor producing signals indicative of the vehicle tilting about its center of gravity. 
   
   
       7 . A suspension control system for a vehicle having a frame and a plurality of wheels, the suspension control system comprising:
 a plurality of liquid springs, wherein one of the plurality of liquid springs is operably interposed between the frame and a respective one of the plurality of wheels and uses a compressible liquid to generate spring forces in response to relative displacement between the frame and the respective one of the plurality of wheels;   a plurality of second volumes of compressible liquid, the plurality of second volumes in at least one second chamber and removably connected to a respective one of the plurality of liquid springs by a respective fluid passage;   a plurality of valves, each of the plurality of valves coupled to the respective fluid passage and selectively operable to place a respective one of the plurality of second volumes in communication with a respective one of the plurality of liquid springs;   a brake sensor; and   a controller electrically coupled to the brake sensor and to the plurality of valves, the controller receiving signals from the brake sensor indicative of a brake application of the vehicle and emitting a control signal to control the plurality of valves;   wherein the controller alters the control signal to change at least one of the group consisting of a pressure, a volume, and a rate of flow of compressible liquid in at least one of the plurality of liquid springs.   
   
   
       8 . The suspension control system of  claim 7 , wherein the plurality of wheels includes two front wheels and wherein, in response to signals from the brake sensor, the controller adjusts respective valve of the plurality of vales at each of the two front wheels to increase spring stiffness and to counteract vehicle dive. 
   
   
       9 . The suspension system of  claim 7 , wherein the plurality of second volumes are combined in one or more second chambers. 
   
   
       10 . A suspension control system for a vehicle having a frame and a plurality of wheels, the suspension control system comprising:
 a plurality of liquid springs, wherein one of the plurality of liquid springs is operably interposed between the frame and a respective one of the plurality of wheels and uses a compressible liquid to generate spring forces in response to relative displacement between the frame and the respective one of the plurality of wheels;   a plurality of second volumes of compressible liquid, the plurality of second volumes in at least one second chamber and removably connected to a respective one of the plurality of liquid springs by a respective fluid passage;   a plurality of valves, each of the plurality of valves coupled to the respective fluid passage and selectively operable to place a respective one of the plurality of second volumes in communication with a respective one of the plurality of liquid springs;   a sensor from which acceleration of the vehicle can be determined; and   a controller electrically coupled to the sensor and to the plurality of valves, the controller receiving signals from the sensor indicative of the acceleration of the vehicle and emitting a control signal to control the plurality of valves; wherein the controller alters the control signal to change at least one of the group consisting of a pressure, a volume, and a rate of flow of compressible liquid in at least one of the plurality of liquid springs.   
   
   
       11 . The suspension control system of  claim 10 , wherein the plurality of wheels include two rear wheels and wherein, in response to signals from the brake sensor, the controller adjusts a respective valve of the plurality of vales at each of the two rear wheels to increase spring stiffness and to counteract vehicle squat. 
   
   
       12 . The suspension system of  claim 10 , wherein the plurality of second volumes are combined in one or more second chambers. 
   
   
       13 . The suspension control system of  claim 10 , wherein the sensor from which acceleration of the vehicle can be determined is an accelerometer.