Abstract:
This thesis develops and demonstrates the research complemented by theory and
applications carried out in ensuring stability of actuator constrained linear control
systems. The work focuses the posteriori approach in the design of controller dealing
with saturation effect. Anti-windup compensator is therefore explicitly synthesized for
ensuring stability of constrained state delay systems and constrained cascade control
systems. Having gone through a detailed study of contemporary research literature, it has
been devised that constrained state delay systems and constrained cascade control
systems are the areas need to be addressed significantly using anti-windup compensator
technique.
Therefore the first prong of research focused stability of constrained state delay systems
using Lyapunov-Krasovskii functionals. Anti-windup compensation is incorporated in
Linear Matrix Inequality (LMI) based formulations in varied conditions of state delay
systems. First, the research taps the stability of constrained multiple state delays system.
This work broadly envisages mixed delay-dependent / delay-independent multiple state
delays, delay-independent multiple state delays, delay-dependent multiple state delays,
delay-independent single state delay and delay-dependent single state delay linear control
systems. Second, the research devises a novel approach of dealing with saturation
problem using two-controller anti-windup design for enlarging domain of stability of
constrained state delay systems. This approach is yet not found in the literature surveyed.
Third, the research addresses an improved asymptotic and exponential stability of
constrained state delay systems by removing the inherent system steady state delay with
higher delay bounds. Lastly, the research concerns stability issue in constrained uncertain
state delay systems.
In the second prong of research a modified full order and static low order anti-windup
compensators are successfully designed for decoupled architecture based actuator
constrained cascade control systems. Besides, the same compensator is designed for rate
limiter incorporated actuator constrained control systems. The design parameters are
based on LMIs and solved using optimization techniques. To validate the design, detailed
experimental results are also generated while successfully applying on temperature and
motor speed control process variables.
It is said that the thesis is a heuristic compendium of inferring the core significance of
anti-windup compensators in overcoming the wind-up effect in PID based process control.
Keywords - Anti-Windup Compensator, Time-Delay Systems, Linear Matrix Inequalities,
Domain of Stability, Pole-Constraints, Cascade Control, Norm-Bounded Uncertainty,
Multi-loop Compensation, Amplitude-Rate Limiter, Motor Speed Control, Cascade-loop
Compensation, Block Diagonal Quadratic Lyapunov, Lyapunov-Krasovskii Functional
and System Identification.