A Simple but Robust Impedance Controller for Series Elastic Actuators

This study presents an impedance controller for series elastic actuators (SEAs), using the singular perturbation (SP) theory and time-delay estimation (TDE) technique. While the SP theory attenuates the requirement for states to be measured, the TDE technique eliminates the requirement for identifying system parameters. Through a numerical analysis and experimental validation, we demonstrate that the proposed controller produces satisfactory tracking performance while–at the same time–pursues wider operational bandwidth and lower driving-point impedance.