A simplified approach to admittance-type haptic device impedance evaluation

Evaluating the transparency, or output impedance more generally, of admittance-type haptic devices is challenging due to their inherently non-back-drivable mechanical characteristics. To address this, we describe a new, simplified evaluation approach that eliminates the need for external test fixtures. The simplified approach relies on the easily obtainable closed-loop position control response of the device in combination with a device/system dynamic model. In addition to evaluating output impedance, the approach can be used of evaluate the overall stable rendering range of the device. Finally, the limitations of the approach are discussed.