Abstract: The method and system employ strings of tension actuators in opposed relationship for controlling motions or deflections of jointed members: for example, for controlling the motions of arms, legs and elephant trunks or flexible antennae in robots and for controlling the deflections of beams and columns in frames and structures. These opposed tension actuators are inflated with controlled air pressures which are oppositely varied from a predetermined common-mode pressure P.sub.o (initial fluid pressure level P.sub.o). In other words, as one tension actuator is being inflated with pressure increasing above P.sub.o, the opposed tension actuator is being inflated with pressure decreasing below P.sub.o for producing motion or deflection of the jointed member in one direction, and conversely for producing motion or deflection in the other direction. The opposed tension actuators have their ends anchored to rigid movable plates or struts containing sockets for the respective joints.