Abstract
On-Off control of the controlled object with static behavior, in other words the controlled object which has no pole at origin, is discussed in this paper. The amplitude of the limit cycle can be made arbitrarily small when the loop transfer function of linear parts besides the relay element takes equivalently the form of first order lag by the properly designed compensator. The transient response of the system depends on the time constant T0 of the first order lag obtained by the above mentioned way. The magnitude of T0 is so determined that the ISE becomes minimum for the step change of the reference value. By this method, such an optimal time constant denoted by Tm depends generally on the magnitude of change of the reference value. When the controlled object is expressed by a dead time plus first order lag of Tp, the optimal value Tm, of the time constant T0 becomes equal to Tp, and does not depend on the reference value. In the latter part of this paper a method for approximating e-Les/1+Tes to the transfer function of controlled objects with higher order lag is also described.
