Design and Experimental Verification of a 3-DOF Spherical Electromagnetic Brake for Haptic Interface

Electromagnetic brake is an efficient device that provides damping to stop the undesired motion of the manipulator. A spherical design of electromagnetic brake is presented with a simple and compact alternative for haptic application. The model exploits coulomb friction to generate fully controllable braking in 3-DOF rotational motion. For miniaturized applications, the design can provide significant torques while rejecting unwanted heat generated in the actuator. In this paper, the analytical models of magnetic force and friction moment are derived, and the brake design is optimized for maximizing the force to input power ratio. The spherical electromagnetic brake is applied for haptic interface and its performance is justified by the experimental results in the virtual reality environment.