Semi-active damper

Abstract

A damper body assembly including: a casing forming therein two mechanically-serial damping fluid mass enclosures; a first and a second piston and a second piston, each housed in separate of the enclosures, each piston having an aperture. First and second damping fluid masses separately filling the enclosures. Sensors producing an electrical output relative to the distance between the pistons. An actuation assembly operable, upon receiving control signals, to independently alter the contribution to the damping coefficient of the damper from each fluid mass as a function of the control signals. A controller including: memory storing a damping policy and instructions implementing a control method based on the policy; and a processor to execute the instructions to receive the sensor output, and transmit a signal to alter the contribution to the damping coefficient of the damper from each fluid mass as a function of the sensor output, policy, and control method.

We claim: 
     
         1 . A damper, comprising:
 a damper body assembly:
 characterized by a longitudinal direction and cross-section direction substantially orthogonal to the longitudinal direction; and 
 comprising:
 a casing forming therein two mechanically-serial damping fluid mass enclosures; 
 a first piston and a second piston, each piston: housed in a separate one of the enclosures, forming therethrough at least one aperture, and movable along the longitudinal direction within the separate enclosure in response to force on each piston; and 
 a first damping fluid mass filling the vacant volume of a first of the enclosures, and a second damping fluid mass filling the vacant volume of a second of the enclosures; 
 
   a set of at least one sensor operative to produce an electrical output relative to the distance between the pistons;   an actuation assembly operable, upon receiving electrical control signals, to independently alter the contribution to a damping coefficient of the damper from each fluid mass as a function of the received electrical control signals; and   a controller,
 in electrical communication with the sensor set and the actuation assembly, and 
 comprising:
 a storage device storing a damping policy and application code instructions implementing a control method based on the damping policy; and 
 a processor communicatively coupled to the storage device, wherein the processor executes the application code instructions to cause the system to:
 receive the sensor set electrical output; and 
 transmit a signal to alter the contribution to the damping coefficient of the damper from each fluid mass as a function of the received sensor set electrical output, the damping policy, and the control method. 
 
 
   
     
     
         2 . The damper of  claim 1 , wherein the damping policy comprises a skyhook policy for the first fluid mass and a ground hook policy for the second fluid mass. 
     
     
         3 . The damper of  claim 1 , wherein the control method is a Lyapunov control method. 
     
     
         4 . The damper of  claim 1 , wherein the damper body assembly comprises one of a mono-tube and the two mechanically-serial damping fluid mass enclosures are separated by a wall in the cross section direction; 
     
     
         5 . The damper of  claim 1 , wherein:
 each damping fluid mass comprises a hydraulic fluid; and   the activation assembly:
 comprises at least one activation assembly valve; and 
 is operable to independently alter the contribution to the damping coefficient of the damper from the first fluid mass and from the second fluid mass as a function of the received electrical control signals using the at least one activation assembly valve to vary an aggregate aperture between a compression chamber on first side of each piston and a rebound chamber on a second side of each piston. 
   
     
     
         6 . The damper of  claim 5 , wherein:
 the activation assembly is external to the damper body assembly; and   altering the contribution to the damping coefficient comprises controlling the flow of damping fluid between a compression chamber on first side of each piston and a rebound chamber on a second side of each piston through an alternate fluid path external to the casing.   
     
     
         7 . The damper of  claim 5 , wherein:
 the activation assembly is internal to the damper body assembly; and   altering the contribution to the damping coefficient comprises controlling the flow of damping fluid between a compression chamber on first side of each piston and a rebound chamber on a second side of each piston through an alternate fluid path internal to the casing.   
     
     
         8 . The damper of  claim 1 , wherein:
 each damping fluid mass comprises a magneto-rheological fluid; and   the activation assembly:
 comprises at least one magnetic field generator; and 
 is operable to independently alter the contribution to the damping coefficient of the damper from the first fluid mass and from the second fluid mass as a function of the received electrical control signals using the magnetic field generator to change the orientation of particles in the magneto-rheological fluid. 
   
     
     
         9 . The damper of  claim 1 , wherein:
 each damping fluid mass comprises an electro-rheological fluid; and   the activation assembly:
 comprises at least one electric field generator; and 
 is operable to independently alter the contribution to the damping coefficient of the damper from the first fluid mass and from the second fluid mass as a function of the received electrical control signals using the electric field generator to change the damping coefficient of the electro-rheological fluid. 
   
     
     
         10 . A damper, comprising:
 a damper body assembly:
 characterized by a longitudinal direction and cross-section direction substantially orthogonal to the longitudinal direction; and 
 comprising:
 a casing forming therein two mechanically-serial damping fluid mass enclosures; 
 a first piston and a second piston, each piston: housed in a separate one of the enclosures, forming therethrough at least one aperture, and movable along the longitudinal direction within the separate enclosure in response to force on each piston; and 
 a first damping fluid mass filling the vacant volume of a first of the enclosures, and a second damping fluid mass filling the vacant volume of a second of the enclosures; and 
 
   an actuation assembly operable, upon receiving electrical control signals, to independently alter the contribution to a damping coefficient of the damper from each fluid mass as a function of the received electrical control signals.   
     
     
         11 . The damper of  claim 10 , wherein the damper body assembly comprises one of a mono-tube and the two mechanically-serial damping fluid mass enclosures are separated by a wall in the cross section direction. 
     
     
         12 . The damper of  claim 10 , further comprising a set of at least one sensor operative to produce an electrical output relative to the distance between the pistons. 
     
     
         13 . The damper of  claim 10 , wherein:
 each damping fluid mass comprises a hydraulic fluid; and   the actuation assembly:
 comprises at least one actuation assembly valve; and 
 is operable to independently alter the contribution to the damping coefficient of the damper from the first fluid mass and from the second fluid mass as a function of the received electrical control signals using the at least one activation assembly valve to vary an aggregate aperture between a compression chamber on first side of each piston and a rebound chamber on a second side of each piston. 
   
     
     
         14 . The damper of  claim 13 , wherein:
 the activation assembly is external to the damper body assembly; and   altering the contribution to the damping coefficient comprises controlling the flow of damping fluid between a compression chamber on first side of each piston and a rebound chamber on a second side of each piston through an alternate fluid path external to the casing.   
     
     
         15 . The damper of  claim 13 , wherein:
 the activation assembly is internal to the damper body assembly; and   altering the contribution to the damping coefficient comprises controlling the flow of damping fluid between a compression chamber on first side of each piston and a rebound chamber on a second side of each piston through an alternate fluid path external to the casing.   
     
     
         16 . The damper of  claim 10 , wherein:
 each damping fluid mass comprises a magneto-rheological fluid; and   the activation assembly:
 comprises at least one magnetic field generator; and 
 is operable to independently alter the contribution to the damping coefficient of the damper from the first fluid mass and from the second fluid mass as a function of the received electrical control signals using the magnetic field generator to change the orientation of particles in the magneto-rheological fluid. 
   
     
     
         17 . The damper of  claim 10 , wherein:
 each damping fluid mass comprises an electro-rheological fluid; and   the activation assembly:
 comprises at least one electric field generator; and 
 is operable to independently alter the contribution to the damping coefficient of the damper from the first fluid mass and from the second fluid mass as a function of the received electrical control signals using the electric field generator to change the damping coefficient of the electro-rheological fluid. 
   
     
     
         18 . A method to dampen forces, comprising:
 providing a damper body assembly, the damper body assembly being characterized by a longitudinal direction and cross-section direction substantially orthogonal to the longitudinal direction, and
 comprising:
 a casing forming therein two mechanically-serial damping fluid mass enclosures; 
 a first piston and a second piston, each piston: housed in a separate one of the enclosures, forming therethrough at least one aperture, and movable along the longitudinal direction within the separate enclosure in response to force on each piston; and 
 a first damping fluid mass filling the vacant volume of a first of the enclosures, and a second damping fluid mass filling the vacant volume of a second of the enclosures; and 
 
   providing an actuation assembly operable, upon receiving electrical control signals, to independently alter the contribution to a damping coefficient of the damper from each fluid mass as a function of the received electrical control signals.   
     
     
         19 . The method of  claim 18 , further comprising providing a controller in electrical communication with a sensor set and the actuation assembly, and comprising:
 a storage device storing a damping policy and application code instructions implementing a control method based on the damping policy; and   a processor communicatively coupled to the storage device, wherein the processor executes the application code instructions to cause the system to:
 receive an electrical output from the sensor set; and 
 transmit a signal to alter the contribution to the damping coefficient of the damper from each fluid mass as a function of the received sensor set electrical output, the damping policy, and the control method. 
   
     
     
         20 . The method of  claim 18 , wherein the control method is a Lyapunov control method.