Mike gave a presentation on Admittance-based Haptic Interface Performance Evaluation and Associated Challenges in a Worshop on Hardware Evaluation Practices held at the IEEE Haptics Symposium in March 2012 at Vancouver, Canada.
The presentation gives an overview of the differences between the impedance based and the admittance based haptic devices and the challenges associated in the evaluating each of these type of devices. The commonly used performance metrics for the evaluation of haptic devices and the challenges encountered in applying them across device types was also presented.
Simplified Device Model
Device Output Impedance
Admittance-based systems require feedback to overcome the non-backdrivable nature due to the high reflected inertia of the device. Figure shows a virtual admittance based control architecture with an inner position loop.