Increasing the impedance range of a haptic display by adding electrical damping

This work examines electrical damping as a means for improving haptic display performance. Specifically, electrical damping, like its mechanical counterpart, can significantly reduce the occurrences of limit cycle oscillations at high impedance boundaries in virtual environments. Furthermore, electrical damping has a number of advantages including its simplicity of design and the ease at which it can be made frequency dependent so that it does not adversely affect a device´s low impedance range. This work examines the theoretical behavior and practical application of frequency dependent electrical damping as it applies to haptic displays. Data is presented illustrating a significant increase in the range of virtual wall behaviors that a one degree-of-freedom device is capable of displaying when electrical damping is added.