A parallel-link robot prototype driven by pneumatic actuators with variable inclination mechanisms

Parallel-link robots, in general, possess high power and high precision owing to the parallel arrangement of actuators; however, their workspace is smaller than that of serial-link robots. In this paper, we develop a parallel-link robot prototype with pneumatic actuators in which a mechanism for varying the actuator inclination is incorporated for the purpose of enlarging the workspace. Our parallel-link robot realizes the rotational and translational motions of the end effector principally by the linear reciprocating motions of pneumatic linear drives mounted on the base. Auxiliary pneumatic actuators are used to adjust the inclination angles of those main pneumatic linear drives. The use of pneumatic actuators to realize the proposed parallel-link robot results in lightweight, compact, and low-cost construction. The workspace and motion transmissibility of our parallel-link robot are analyzed through simulations based on kinematics; then, experimental investigations are carried out using the prototype.