Robust analytical scheme for linear non-square systems

This paper proposes an analytical design method for the linear multivariable non-square systems with multiple time delays and nonminimum-phase zeros. Based on Internal Model Control (IMC) theory, a multivariable non-square controller of full matrix form is designed for the non-square processes. In the controller design procedure, a simple method is presented to factor the transfer function matrix of the processes into minimum-phase and nonminimum-phase portions. In order to improve the robustness of the control system, a filter is designed in the control structure. To guarantee the robust stability of the system, an analytical calculation method is also proposed to obtain the low bounds of the control parameters. Simulation is illustrated to demonstrate the validity of the proposed control schemes.