MODELLING AND CONTROL OF A TWO-LINK FLEXIBLE MANIPULATOR

Abstract

Industrial robots have lumped flexibility at the joints as well as distributed flexibility due to the elasticity of their arms. Because of the flexibility, undesirable vibration occurs during the motion. If the robot’s flexibility is suitably modelled and advanced control strategies are formulated, the robot performance can be improved. In this paper, a certain class of robots is considered, namely an anthropomorphic two-link flexible manipulator. The links’ flexibility is represented by discretizing the links into a series of masses and springs. Using this model, the equations of motion for the robot are derived using Lagrangian dynamics. Motor torques should be controlled in such a way that the required response of the robot is achieved with minimum vibration. For observing the state variables, accelerometers are attached at the tip of each link. Simulation results of two control techniques show success in controlling the tip vibration.