A multivariable controller, applicable to coupled multi-channel servosystems, is described. The controller is designed from an estimated matrix fraction description plant model, and allows the channels to be decoupled with individually specified pole positions. The controller is applied to a two-channel electro-hydraulic servosystem, and demonstrates a significant reduction in interaction compared to non-decoupling controllers.
Plummer, A. R., & Vaughan, N. D. (1997). Decoupling pole-placement control with application to a multi-channel electro-hydraulic servosystem. Control Engineering Practice, 5(3), 313-323. https://doi.org/1016/S0967-0661(97)00008-7