טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentClarice Wagner-Nachshoni
SubjectControl of Multi-Link Flexible Structure
DepartmentDepartment of Mechanical Engineering
Supervisor Full Professor Halevi Yoram


Abstract

Control of flexible structures is an important issue from both theory and application points of view. As a result, there are many works investigating the modeling aspects, the achievable performance, and the suitable control methods.

In this work a new method for tracking control of flexible structures governed by the wave equation is proposed. The first step is deriving an exact, infinite dimensional, transfer function, relating the actuation and measurement points, for a link with general boundary conditions. The results were then extended to the multi-link case, where three modeling methods were presented and discussed. A key element of the model is the existence of time delays, due to the wave motion, which play a major role in the controller design. These delays disappear in common finite dimension modeling methods.

The proposed design methodology combines the advantages of both collocated and non-collocated control and enables tight tracking. It consists of two stages. First, the collocated rate loop is closed with a controller that leads to an equivalent open loop transfer function that is delayed, but otherwise finite dimension. The next step is closing the non-collocated loop to achieve the tracking requirements. This controller has the structure of Dead Time Compensator, and it consists of a state observer, a predictor, and predicted state feedback. The overall closed loop transfer function has a rational part with dynamics that can be assigned at will, plus a delay. The entire control design enabled by, and closely related to, the exact, infinite dimension modeling.