The article concerns the actuator with one pneumatic artificial muscle and spring which is acting again the direction of pull force of the pneumatic artificial muscle. This solution needs only one inlet and one outlet of the electromechanical pneumatic valve. The article concerns also the actuator with two McKibben´s type pneumatic artifical muscles in the antagonistic configuration. They are acting again the force of the other artificial muscle. The actuator is realized by using of two artifical muscles of Shadow Air Muscle type. This solution needs two inlets and two outlets of the electromechanical proportional or on – off pneumatic valves. At last cause it is suitable for the solving of low cost bioservosystems. The paper contents the mathematic descriptions, static characteristics of the parts of actuator and characteristics of the all mechanism.