Electro-rheological fluid brake and actuator devices and orthotic devices using the same

An electro-rheological fluid actuator for generating a torque or force output and for providing resistance to a torque or force input, comprising:

• a housing comprising an insulative case, an input/output shaft rotatably mounted in the case;
• a plurality of rotatable members disposed arcuately within the case and coupled to the shaft;
• a plurality of rotatable electrodes formed as segments of a cylinder, each electrode mounted to an associated rotatable member for rotation therewith;
• a cylindrical ground electrode fixed to the case and concentric with the rotatable electrodes, a gap disposed between the ground electrode and the rotatable electrodes;
• an electro-rheological fluid disposed within the gap;
• and
• a plurality of linear actuator elements disposed within and motively coupled to an associated rotatable member to actuate rotation of the associated rotatable member.