Control of Flexible Payloads Grasped by Actuated Grippers Undergoing Large Rigid-Body Motions: Part I — Dynamics

Abstract

This paper is Part I of a preliminary study to simultaneously control vibration and static shape deformation in flexible payloads. In Part I, the dynamics of a flexible payload grasped by an actuated gripper, which is attached to a rigid link robotic manipulator, is investigated using the component mode synthesis (CMS) method. Robot and actuator dynamics are also added to the system dynamic model to fully define the rigid body motion and elastic motion of the flexible payload. The CMS method is employed to explicitly model the coupling between the payload and actuators, and to reduce the system order. With the addition of fixed-interface quasi-static modes to fixed-interface vibration normal modes and actuator constraint modes an improved component mode representation is defined. Here, it is found that the inclusion of quasi-static modes in the CMS formulation results in increased ac curacy for simulation of dynamic behaviour of flexible payloads subject to both gravity and robot motion induced forces. Numerical examples are presented to demonstrate the effectiveness of the new component mode representation for the given robotics problem. In Part II [9], the two-time scale modeling (TSM) technique is used taking advantage of two-time scale behavior between the quasi-static modes and vibration modes in the dynamic model.