Mechanical power factor as performance index of bilateral teleoperation systems

Performance indices are useful as design guidelines of control systems. One of useful performance indices for bilateral teleoperation systems is transparency. It evaluates bilateral teleoperation systems based on a definition of the ideal state of bilateral control. Since the concept is intuitive, it has been widely used in many applications. The evaluation or analysis based on transparency is usually done in frequency domain by using frequency characteristics of the subject control systems. However, in some applications, online performance evaluation methods or performance indices by using experimental or simulation data are more desirable and useful. In this paper, a concept of mechanical power factor (MPF) is studied as an eligible performance index for online performance evaluation of bilateral teleoperation systems. Some fundamental studies on impedance transmission verify the validity of MPF. Moreover, the verification is extended to cases with time delays. The results clarify that MPF is valid as a performance index of bilateral teleoperation systems in the cases with/without time delays.