Motion Generation of a Casting Manipulator With a Large Working Space

Casting manipulator has a potential to achieve far larger working space with simple mechanism by casting its gripper than the conventional types of robot. In order to enlarge the working space of the manipulator, the gripper must be cast at a high-speed. In casting the gripper at a high-speed, the motion of the manipulator must be generated which makes the best use of the actuator power while the posture of the gripper is kept stable. The present paper proposes new methods to cast the gripper at higher-speed. In proposed methods, transient swinging motion of which amplitude ranges from 90° to 180° or rotating motion of the manipulator are generated before casting the gripper by modifying the method previously proposed by Arisumi et al.. For generating a rotating motion, a new approach is also proposed that varies the length of the flexible link while generating the motion. Numerical simulations have been carried out to evaluate the methods from the criteria of the casting speed of the gripper, the required time for generating motion, and the stability of the posture of the gripper.