Loop shaping controller design using the sbode plot

This paper presents a new concept for assisting control engineers with the design of high performance servo systems. Classical loop shaping concepts are the basis for this new method. The idea is a modification of the traditional Bode plots to provide closed-loop frequency response information graphed as contours along with the usual open-loop magnitude and phase response graphs. The concept can reduce the trial and error needed to obtain a good design by more clearly showing the relationship between the open-loop and closed-loop frequency responses. The paper shows a design example using this method.