Synthesis of uncertain cascaded multiple loops systems with time delay

This paper presents a frequency domain design method for uncertain cascaded multiple loops systems with time delays. It is shown that the plant uncertainties and time delays can be transferred to the values of equivalent external disturbances at the plant output. Thus, the control design problem coping with parametric and time delay uncertainties can be treated as an equivalent external disturbance attenuation problem. An example is provided to illustrate the proposed design method.