Motion Control

Abstract

The general-purpose jointed-arm robot is first introduced together with a model that applies also to other mechanisms whose motion is to be controlled. A generalised feedback linearising control law is then given. Modelling simplifications applicable to geared mechanisms are then developed.

Dynamic lag pre-compensation is presented, including a polynomial controller with inbuilt derivative feedforward to aid the implementation of the pre-compensation..

Next, the important topic of frictional energy minimisation is introduced, which if implemented on a large scale can drastically reduce the carbon footprint. The optimal control strategy is first formulated with the aid of Pontryagin’s method. This is used to derive an optimal reference input function that can be followed using a controller with a dynamic lag pre-compensator to implement optimal feedback control. The performance improvement over traditional control methods is assessed.

The appendix presents reference input function planning using cubic and quintic splines, a method enabling exact derivatives to be computed for dynamic lag pre-compensator implementation.