An alternative approach in sensing simultaneous 3-DOF motions

Due to the proliferation of new technologies and demands for dexterous robotics manipulators, multi-degree-of-freedom (MDOF) actuators are widely sought after. These actuators are utilized primarily in the assembly sectors, precision machining and active tracking devices. Prior to realizing a feasible MDOF actuator for any practical use, positional closed loop feedback is of paramount importance. To date, commercially available encoders are mainly limited to single-DOF sensing. Furthermore, integration of these sensors inherently introduces mechanical linkages that compromise the overall performance of the system. This paper introduces an alternative approach in 3-DOF motions sensing leveraging on contactless sensing of Anisotropic Magneto-Resistive (AMR) sensors. The theory and design methodology of this sensing method is being discussed and presented. Experimentation was also conducted for conceptual verification on existing spherical actuator. The uniqueness of this technique lies in the exploitation of existing magnetic field generated from the rotor. The test platform being established is expected to lay the foundation for optimizing key parameters. With the successful implementation of this new sensing system, future development will be focusing on real-time measurement and control.