1992 Volume 28 Issue 1 Pages 59-66
In the tracking control problems, e. g. robotic arms, tracking performance with high speed and high accuracy has been required. The feedforward controller by which the controlled output is driven to the desired one with no error may cause undesirable pole/zero cancellation.
To avoid undesirable pole/zero cancellation, the feedfoward controller based on phase cancellation has been proposed. The phase cancellation implies that the overall frequency response exhibits zero phase shift for all the frequencies. This is termed Zero Phase Error Tracking Controller (ZPETC) and is a discrete-time preview controller.
This paper presents a general form of ZPETC and the explicit parametrization. The contributions are as follows: (1) The synthesis of ZPETC with minimum preview steps which makes the gain of the overall controlled system equal to unit at zero frequency is presented. The controlled output is driven to a step and ramp desired one in a finite steps. (2) The synthesis of ZPETC by which the controlled output is driven in a finite steps to the desired output consisting of a time polynomial is presented.
