TRAJECTORY CONTROL THROUGH PERIODIC LINEARIZATION OF ROBOT DYNAMIC MODEL

Abstract

Industrial robots are serial link manipulators whose dynamic characteristics are highly nonlinear. The robot advance control systems which covers methods based on adaptive control theory, reduces the manipulator control problem from non-linear to controlling a linear system about a nominal trajectory. In this dissertation work, trajectory control of two link manipulators through linearization of manipulator dynamics is studied. The joint control scheme consists of two independent multivariable feedforward and feedback controllers. The feedforward controller is the minimal inverse of the linearized model of robot dynamics and contains only proportional double derivative (PD2) terms; implying feedforward from the desired position, velocity and acceleration. This control ensures that the.manipulator joint angles track any reference trajectories. The feedback controller is of the proportional, derivative type to achieve pole-placement. Finally,an attempt is made for control of two-link manipulator based on the linearized model by, simulating on a computer. The result so obtained for tracking the reference trajectories by joint angles are satisfactory.