Four-State Rotary Joint Control: Results With a Novel Programmable Brake

This paper outlines the development of a new programmable rotary brake which can restrict motion in one direction while allowing free rotation in the opposite direction. The design, implementation, and performance of a fully functional prototype are described, followed by the development of control schemes which allow different operational modes. A number of unique performance parameters for the brake are identified and analytical methods for their evaluation are proposed. The prototype, which was developed using commercially available miniature brakes, has a cylindrical shape and is characterized by a compact, modular, and cost-effective design which can be implemented into man–machine interfaces to restrict undesired user motion without the need for an explicit force sensor. The programmable brake concept proposed here is advantageous in these applications, where close cooperation with humans poses significant safety risks, due to the inherent safety of a mechanism which is not able to move autonomously in the event of a malfunction.