Abstract: The stable range of a 1 degree-of-freedom haptic system in admittance display is discussed. The human operator is regarded as a combination of passive impedance and active input in the system. And the virtual environment is assumed to be passive. Through analogous treatment between the haptic system and electrical network system, the port theory is used to analyze the system. Considering a simple but typical virtual environment of a pure mass, the stable boundary of the virtual mass is derived. Matlab simulation proves the validity of the proposed method. The method can be applied for performance evaluation in the device design.

Key words: auto-control technology, force reflection, admittance display, stability, transparence, two-port