Control of a Biomimetic Robotic Finger Using Antagonistic Twisted and Coiled Polymer Actuators: Simulation and Experimental Validation

The advancement of smart materials has con-tributed to their expanded role in robotics, despite their typically low operational frequency. Examples of these materials include SMA wires and TCPs, which are activated by heat and require cooling to return to their original state without external forces. This study introduces a new mechanism for the Surena- V humanoid robot's finger, inspired by the function of the human hand. The design incorporates two TCP actuators and tendons to control the flexion and extension motion of the finger joint. The force to voltage transfer function of the TCP actuators were established. Additionally, a PD controller was implemented to regulate the joint angle, with real-time angle measurements recorded via a potentiometer. The resulting data demonstrated that utilizing two antagonistic actuators can effectively control the joint angle without steady-state error or oscillations, without the need to provide cooling or spring return.