Stability and performance of human-robot interaction

In the work presented, extenders are defined as a class of robot manipulators worn by humans to increase human mechanical strength, while the wearer´s intellect remains the central control system for manipulating the extender. The human, in physical contact with the extender, exchanges power and information signals with the extender. The author gives a summary of the ongoing research work on human-machine interaction in the sense of the transfer of power and information signals. A single-degree-of-freedom extender has been built for theoretical and experimental verification of the extender dynamics and control. System performance is defined as amplification of human force. It is shown that the greater the required amplification, the smaller the stability range of the system is. A condition for stability of the closed-loop system (extender, human and environment) is derived, and, through both simulation and experimentation, the sufficiency of this condition is demonstrated