Study on subspace control based on modal analysis (1st report, application to swing-up control of inverted pendulum system)

As a new control technique, subspace control method is developed in an effort to carry out the finely-tuned control easily and efficiently for a complicated and large-scale mechanical system. In the subspace control method, the minimum and optimum subspace suited for the control specification is extracted from the whole state space by applying the concept of modal analysis and the feedback control based on the modal coordinate is carried out in the subspace. It is a feature of the subspace control method to make positive use of the dynamical characteristics of the controlled object in the design of control system. In addition, decreasing the dimension of controlled object based on the dynamical characteristics leads to simplification of the design of control system, reduction of mechanical overload caused by the control and saving in consumed electric power. For the clarification of the fundamental concept, in this report, the subspace control method is formulated for swing-up and stabilizing controls of an inverted pendulum system. The effectiveness is verified from the numerical simulation and the experiment.