A Polyurethane-based Compliant Element for Upgrading Conventional Servos into Series Elastic Actuators*

This paper presents a novel compliant spring system designed to be attached to a conventional robotics servo motor, turning it into a series elastic actuator (SEA). The system is composed by only two mechanical parts: a torsional polyurethane spring and a round aluminum support for link attachment. The polyurethane spring, had its design derived from a iterative FEM-based optimization process. A magnetometer based circuit is used to measure angular displacement and communicate it through a RS485 bus protocol.