Enhancing the Force Transparency of the Energy-Reflection-Based Time-Domain Passivity Approach

The time-domain passivity approach (TDPA) was developed and applied to tackle a variety of control challenges such as noncollocated force sensing, authority scaling, or delayed coupling in robotic applications. Specifically for delay, recently, the energy-reflection-based TDPA (TDPA-ER) was proposed to improve position tracking and force-feedback quality. In contrast to the conventional TDPA, the TDPA-ER intrinsically prevents position drift, thus substantially increasing the coupling rigidity. Here, we extend the TDPA-ER to further enhance the force transparency perceived by the operator in teleoperation scenarios. The extension is based on two independent control strategies that, among others, reorganize the energy distribution of TDPA-ER and ensure more continuous force profiles through the deflection-domain passivity approach (DDPA). Experiments confirm the improvement of force-feedback quality and force continuity with regard to TDPA-ER. Furthermore, it is shown that interactions with dynamic objects and active environments can be handled robustly with the proposed teleoperation control strategies.