The muscle spindle, that is a sensor in vivo, has an interesting structure. To combine an actuator and a sensor develop a unique sensor system, a linear stage and a tensiometer was combined for a prototype tensiometer. But it was not perfect muscle spindle mimeties, and it had necessity, to compare both the control theory of the muscle spindle and artificial muscle spindle. So the control block diagram difference between the tensiometer and the muscle spindle was compared in this study.