Speed estimation improvement using full order state observer for a haptic interface

A haptic system is an articulated mechanical structure with motors, sensors as well embedded electronics allowing force feedback. It enables the user to interact with virtual reality through the sense of touch and sight. Speed control of such systems usually becomes unstable at low speed range due to the imposed speed by the operator's hand. This paper describes implementation of full order state speed observer for a single degree of freedom haptic interface driven by permanent magnet synchronous motor. This method allows accurate speed estimation. The observer design criteria for haptic interface are analyzed in this paper. In addition, its influence on system stiffness is illustrated.