抄録
A design method will be useful if it calls for the minimum amount of knowledge about the controlled process, since identification of the state equation is not an easy task especially in the field of process control. From this point of view, the author previously developed a general design principle which allows one to design control systems based upon partial knowledge about controlled process dynamic characteristics.
The principle is firstly to represent the dynamic characteristics of the controlled object, the compensator and/or the controller, the control system, and the desired reference model by sequences of parameters, and secondly to match the control system parameters to the desired ones from the beginning of the sequence to so far as some parameters remain adjustable.
The principle has been successfully applied to single-input single-output continuous-time and discrete-time control systems, taking the sequence of the moments of the impulse response for the representing sequence of parameters.
In this paper a design formula for I-PD type decoupled control systems is derived according to the principle. The system to be designed here is to meet the following requirements: (C1) Each decoupled subsystem has zero steady-state error.
(C2) Each decoupled subsystem has adequate damping characteristics.
(C3) Each decoupled subsystem has the shortest rise-time on satisfying (C1) and (C2).
(C4) The remnant coupling due to imperfect decoupling among the subsystems is as small as possible.
The formula obtained is quite simple and is direct extention from the single-input single-output case. It should be stressed that the formula has a kind of matching property, so that the simpler the decoupling and controlling mode is with small number of adjustable parameters, the less the number of controlled process parameters to be known becomes.
Some response curves of a designed control system are demonstrated which show the effectiveness of the method.
