Rejection of fixed direction disturbances in multivariable electromechanical motion systems

This work discusses rejection of disturbances with known directions in multivariable motion systems. It is shown how frequency domain tradeoffs in multivariable control motivate a design based on disturbance directions. A multivariable design method is presented to design centralized controllers that reject disturbances only in relevant directions. A model of an industrial motion system is used to demonstrate the theory. It is shown how the proposed design method resembles the solution of a competing H∞ design and offers the ability to interpret H∞ centralized control solutions, and understand the tradeoffs inherent in such a design.