A new two-degree-of-freedom internal model decoupling control of three-motor drive system

Multi-motor drive is a multi-input multi-output (MIMO), nonlinear and strong-coupling system. Its high precision coordinated control performance can meet the requirements of many drive applications, such as urban rail transit, paper making, electric vehicle drive, and steel rolling. To decouple the velocity and the tension of the three-motor drive system, a new control strategy is proposed by incorporating two-degree-of-freedom internal model control (IMC) with back-propagation (BP) neural network generalized inverse (NNGI). Firstly, the composite pseudo-linear system is formed by making NNGI connect in series with the original system. Secondly, a two-degree-of-freedom IMC method is introduced to this pseudo-linear system. Finally, the simulation results are given, verifying that the proposed strategy can not only effectively attain decoupling towards velocity and tension, but also transform this MIMO nonlinear system into a number of SISO linear subsystems with open-loop stability, so as to improve the dynamic characteristic of the system.