טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentGudin Roman
SubjectRobust Control Using Dead-Time Compensators
DepartmentDepartment of Mechanical Engineering
Supervisor Professor Leonid Mirkin
Full Thesis textFull thesis text - English Version


Abstract

Dead-time systems are control systems containing time delays in the feedback loop. One widely used scheme for the control of dead-time systems is the so-called dead-time compensation (DTC) controller configuration (the Smith predictor and its modifications). It is known that DTCs may be very sensitive to uncertainty in the loop delay (weak dead-time tolerance) and troublesome in implementation. Yet the underlying mechanisms of these problems are still not well understood.

This research examined the aforementioned two problems associated with DTCs. First, it was shown that the reasons for the high sensitivity to delay uncertainty can be revealed using standard Nyquist criterion arguments. In particular, it was argued that this phenomenon is caused by proliferation of crossover frequencies, which, in turn, is facilitated by the use of DTCs. This conclusion leads to somewhat more conscious guidelines for the design of DTC-based controllers. Second, existing approaches to the numerical implementation of DTC-based controllers were studied using laboratory experiments. It was shown that the out-of-the-box use of these approaches may not be feasible for the implementation even on relatively powerful real-time control hardware. Some remedies for these problems are proposed and experimentally validated.