Magnitude and symmetric optimum criterion for the design of linear control systems - what is it and does it compare with the others?

The magnitude and symmetric optimization techniques are two related methods for designing optimal linear control systems in the frequency domain. Both methods have been used in industry for some time, yet they do not appear to have been well documented in the English control engineering literature. The development of the criterion is examined, including general solutions for typical controllers. As a basis for comparison, time-domain response optimization techniques such as minimizing the integral time absolute error, along with state-space techniques, i.e., pole placement, are briefly reviewed. Personal computer simulation results for a normalized position control system are given to illustrate these methods.