A novel 3-DOF sensing methodology for spherical actuator

Ensuing the advancement of new technologies in the manufacturing sector, there is an increasing demand for dexterous, multi-degree-of-freedom (MDOF) robotics manipulators or actuators. 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 presents an innovative approach in 3-DOF motions sensing leveraging on contactless sensing of Anisotropic Magneto-Resistive (AMR) sensors. The theory and design methodology of this novel sensing method is being discussed and detailed in the paper. Experimentation was also conducted for conceptual verification on existing spherical actuator. The uniqueness of this method lies in the exploitation of existing magnetic field generated from the rotor design and correlating them to the sensors output. The test platform being established is expected to lay the foundation for optimizing key parameters for this configuration. With the successful implementation of this new sensing system, future development will be focusing on real-time measurement and control.