Choice of Decoupled Control Law of Large-Scale Mechanical Systems

Abstract

The decoupled control of large-scale mechanical nonlinear systems is discussed. The system is considered as a set of subsystems each associated to one degree of freedom of the system. For each subsystem local control is chosen in order to stabilize it. Since the destibilising influence of coupling among subsystems could be too strong the nominal-programmed control and the global control are introduced. The global control can be introduced in the form of force-feedback since in mechanical systems coupling among degrees of freedom is represented by forces. The problem of redistribution between the local and the global control is discussed, from the standpoint of global system stability and suboptimality of the chosen control law. Also the problem of redistribution between the part of the model associated to the subsystem and the part of the model associated to the coupling among subsystems is considered. The analysis is demonstrated on an example of an industrial-manipulator with six degrees of freedom.