Improving the Energy Efficiency by Using Quasi-Passive-Dynamics-Based Elastic Actuator

Electric actuators are commonly used in machines and the optimal energy efficiency can be achieved only at certain speeds. This letter introduces the Quasi-Passive-Dynamics-based Elastic Actuator (QPD-EA), which enhances energy efficiency by leveraging passive dynamics and energy recycling. Instead of directly linking the motor to the robot arm, the motor charges a spring at its optimal energy efficiency speed, and a clutch mechanism controls energy transfer between the spring and the robot arm, enabling efficient movement in any desired direction. The design, modeling, prototype, and experimental validation are described in detail, showing that the QPD-EA consumes 86% less energy than conventional actuators for the same motion, reducing energy use from 154 mJ to 21 mJ. This approach can significantly improve the energy efficiency of actuators in pick-and-place operations.