Abstract
The triple arm mechanism is a simple and basic spatial parallel mechanism with three degree of freedom, which consists of a based platform, a movable platform and three two-link-chains having the actuated prismatic joint. It is important to make clear the kinematics near the limit position for the parallel mechanism. Sensitivities analysis is useful to estimate the transmissibility, but sensitivities do not indicate the force to support the movable platform. In this paper, static analysis is done to make clear the force transmitting through the pair, and instantaneous screw axis indicating the motion of the movable platform is derived, and transmissibility characteristic is shown by means of the forces supporting the movable platform.
