Linear-acting controllable pneumatic actuator and motion control apparatus including a field responsive medium and control method therefor

Abstract

A controllable pneumatic apparatus including a pneumatic actuator coupled with a linear-acting brake including a field responsive medium. The pneumatic actuator has a housing with a gas cavity, a first piston slidably disposed in the gas cavity subdividing the gas cavity into first and second gas chambers, and an output member coupled to the first piston. The linear-acting controllable brake includes a medium containing cavity subdivided into a first and second chambers, and a second piston rigidly interconnected with, and longitudinally aligned with, the first piston. A passageway interconnects the first and the second chambers and a field responsive medium (e.g., a magnetic fluid) is contained in the passageway. A field generator produces a field to change a rheology of the medium and cause a braking force to be applied to the output member to control motion thereof. A preferable control method implements motion control based upon the kinetic energy and the braking force in the system.