Fundamental Design Limitations in the General

Feedback Configuration


Professor James Freudenberg


Department of Electrical Engineering

and Computer Science


University of Michigan


Why another talk on fundamental design limitations? Because questions concerning limitations continue to arise in applications, and new developments in the theory are often required to obtain answers. In this talk we will describe a theory of fundamental limitations applicable to the so-called general control configuration, in which the performance output,  z, may differ from the measured output, y, and the disturbance input, w,  enters the system differently than does the control signal, u. At first glance, this control configuration does not look amenable to analysis because it is so general. Yet applications as diverse as elevation control for a military tank, active noise control, and control of advanced technology powertrains fall naturally into this framework. We develop a theory of design tradeoffs imposed upon the ability of control to attenuate the effect of a disturbance upon the performance output. We will also illustrate design tradeoffs that may exist between disturbance attenuation and stability margin in the general control architecture that do not exist in single loop control.

Friday, March 15, 2002

3:30 - 5:00 p.m.

1500 EECS