Benchmark problem solution by quantitative feedback theory

Quantitative feedback theory is used to synthesize compensators satisfying various design specifications stipulated in the "benchmark problem" statement. The primary goal in this design technique is to keep the cost of feedback, as measured by the controller bandwidth, as low as possible while realizing the specified performance specifications in the presence of plant uncertainty (parametric in the low frequencies and unstructured in the high frequencies) and external disturbances. The order of the compensators is directly related to the performance objectives and bandwidth limitations. A fifth-order compensator for design 1 and a ninth-order compensator for design 2 were obtained for satisfying the performance specifications with finite controller bandwidth. If sensor noise is not considered, then these compensator orders can be reduced.