Pneumatic muscle(PM) is the research focus of bionic robot. Therefore, the fiber knitted sleeve of PM is replaced
with shape memory alloy(SMA) and the mechanism is designed. Through equivalent translation to deformable cylinder, static
driving force model is established. Through equivalent analysis of contraction, damping and elastic element of PM, dynamics
driving force model is derived. An impedance control scheme with inner position PID loop is designed for active compliant
in Cartesian space. And impedance adjustment target is built based on damping-spring model. By Laplase transform and
frequency domain analysis, stable condition of impedance control is given. On Matlab, the control simulations of varying
impedance parameters are done to analyzing impact of parameters to compliant character. Simulation results show that
generalized rigid is the main impact factor of contact force, and impedance control proposed can achieve harmony complain
of force and position.