Multivariable QFT control of coaxial double brushless DC motors system

On the basis of underwater table, a pre-controller and an internal model reference loop controller are designed using multivariable quantitative feedback theory (QFT) for the uncertain MIMO system after analyzing the coaxial double brushless DC motors system. The two controllers cause the coupled system to behave like the uncoupled system with properly choosing pre-controller and the reference model. To realize robust disturbance rejection and robust tracking, an outer-loop controller is designed in the well-known sequential design. The final results indicate that the request of system performance is satisfied, at the same time, the applicability and effectiveness of the proposed method is verified