Electro-rheological fluid damped actuator

An electro-rheological fluid damped actuator for controlling the orientation and displacement of a control surface with respect to a control surface axis, said actuator comprising:

• a cylindrical housing defining at least two interior chambers;
• a piston and rod assembly movably disposed in said interior chambers further isolating and defining separate hydraulic chambers and pneumatic chambers, said piston and rod assembly further operatively connected to said control surface such that any movement of said piston and rod assembly causes a corresponding movement of said control surface to a commanded position with respect to said control surface axis;
• a plurality of pneumatic inlet valves in communication with said pneumatic chambers and further adapted for accepting a supply of pressurized gases for moving said piston and rod assembly to a predetermined position;
• a position sensor which generates a signal corresponding to the position of said control surface with respect to said control surface axis;
• a electro-rheological fluid valve disposed between the hydraulic chambers and in communication therewith, said electro-rheological fluid valve adapted for restricting the flow between said hydraulic chambers;
• an electro-rheological fluid disposed in said hydraulic chambers and in said electro-rheological fluid valve, said electro-rheological fluid flow further provides an active and variable damping force on said piston and rod assembly;
• and
• an electrical circuit having a plurality of input signals and an output signal, said input signals include said position sensor signal and another signal corresponding to said commanded position to which said actuator is commanded, said output signal creates an electric field proximate said electro-rheological fluid valve whereby the viscosity of said electro-rheological fluid exposed to said electric field is varied in accordance with the magnitude of said electric field.

A method for damping an actuator, said actuator comprising a cylindrical housing defining at least two interior chambers and further having moveable elements disposed in each said chamber further isolating and defining separate hydraulic chambers and pneumatic chambers, the movement of said moveable elements in response to pneumatic forces controls the orientation and displacement of a control surface with respect to a control surface axis, and method of damping comprising the steps of:

• placing a position sensor proximate said control surface which generates a signal corresponding to a position of said control surface with respect to said control surface axis;
• inserting a electro-rheological fluid valve between the hydraulic chambers and in communication therewith, said electro-rheological fluid valve adapted for restricting the flow between said hydraulic chambers;
• filling said hydraulic chambers and said electro-rheological fluid valve with an electro-rheological fluid whereby said electro-rheological fluid flow provides an active and variable damping force on said moveable elements;
• and
• connecting an electrical circuit having a plurality of input signals and an output signal to said electro-rheological fluid valve, said input signals include said position sensor signal and another signal corresponding to a position to which said actuator is commanded, said output signal creates an electric field proximate said electro-rheological fluid valve whereby the viscosity of said electro-rheological fluid exposed to said electric field is varied in accordance with a magnitude of said electric field, which in turn restricts and hydraulic flow through said electro-rheological fluid valve to achieve a damping effect.