Decentralized Control For Interconnected Lagrange System With Nonlinear Input

With the socialization and systematization of modern society, a variety of complexlarge-scale systems have been widely used in all walks of the society, espescially theLagrange system has attracted the researchs’ attentions at home and abroad. Consideringthe properities of the Lagrange system, such as high dimension, strong nonlinearity andhigh interconnection, the development tendency for its control is to combine moderncontrol theory with decentralized control. Besides the nonlinearities shown in the actuatorsproduce an big effect on system control in the practical application.Therefore,interconnected Lagrange system with nonlinear inputs is discussed in this paper, and itsdecentralized control strategies are studied.Firstly, the Lagrange system, which contains the disturbances of its own and theinterconnection bounded by high order polynomial, is investigated in this paper. And thecase with non-symmetric dead-zone input is taken into consideration. Combined withneural network strategy, a decentralized adaptive controller is proposed for theinterconnected Lagrange system with dead-zone input. So the limitation arising from thedead-zone is eliminated, meanwhile the stability and robustness are guaranteed.Secondly, the control problem for the same systems with input saturation is studied.Considering the limitation of actuator, an auxiliary controller associated with the input isproposed for each subsystem. Then, a decentralized control algorithm based on slidingmode strategy and adaptive control is presented for the interconnected Lagrange systems.Thus the purpose of trajectory tracking is achieved.Finally,3-DOF Phantom robotic system Premium1.5HF is used to verify theeffectiveness of the proposed decentralized methods for the interconnected Lagrangesystem with dead-zone input.