A novel dynamic evaluation method and its application to a 4-DOF parallel manipulator

Abstract

Taking into account that the velocity and acceleration limits of the end-effector are specified rather than the physical limits of the actuators in the design purpose of a robot, this paper proposes a novel method to evaluate the dynamic performance of the robot along joint-space directions. Based on the given ranges of end-effector velocity and acceleration in task space, the required torque along all joint-space directions are obtained based on the velocity term and the acceleration term in dynamic model, respectively. Furthermore, the actual torque range of each actuator is derived to produce the required torque along all joint-space directions. Considering all the effects of the acceleration term, the velocity term and the gravitational term, two global dynamic performance indices that reflect the minimum range of actuator torque and the ratio of the required torque range to the actual torque range in the whole workspace are presented. This method is validated by utilizing it to evaluate the dynamic performance of a novel 4-DOF parallel manipulator with translational and rotational motion for FSW. This method conforms with the design process of robotic manipulators and would be useful for optimum design, dynamic performance evaluation and actuator selection of a robot.