Torque characteristics of antagonistic pneumatic muscle actuator with an oval cam

Abstract

The current equipment for generating of the rotational motion by antagonistic pneumatic muscle actuator is standardly solved with a circular pulley, on which a flexible strip is strung and its ends are connected with artificial muscles. However, in this solution, torque and stiffness of such actuator decrease with increasing rotation of the actuator arm. This is due to the nonlinear decrease of muscles forces according to their contraction. By application of the oval cam, a smaller decrease in torque and thus the greater and symmetrical stiffness of the actuator with pneumatic artificial muscles can be obtained.