Robust and Optimal PID Controller Synthesis for Linear Time Invariant Systems
Abstract
We dealt with new approaches to the design of Proportional-Integral-Derivative (PID) controllers and solved three important open problems: 1) Optimal design of H∞ continuous time controllers 2) Optimal design of H∞ discrete time controllers and 3) Design of PID controllers for prescribed settling time. We also deal with optimal Dynamic Compensator design for controllable and observable systems.
The main result of the first problem is a constructive determination of the set Sγ of stabilizing continuous PI and PID controllers achieving an H∞ norm bound of γ on the error transfer function. This result utilizes the computation of the complete stabilizing set S. We also point out connections between this H∞ design and Gain and Phase Margin designs.
The main result of the second problem is a constructive characterization of the set Sγ of stabilizing digital controllers achieving a prescribed bound γ on the error transfer function. This is accomplished by utilizing the computation of S, the set of all PID stabilizing controllers. The minimum achievable γ, denoted γ∗ is also determined.
The main result of the third problem is a constructive determination of the set S(σ) of stabilizing PI and PID controllers with closed loop poles having real parts less than −σ. The signature method is applied to obtain the set S(σ) in the controller parameter space. The maximum achievable σ for a given plant is also determined.
The main result of the last problem is a new approach to design an optimal dynamic compensator. The system is augmented with a proper number of integrators and the state feedback of the augmented system is considered with a design parameter. The dynamic compensator is then designed such that the eigenvalues of the augmented system is identical to the closed loop specboundtrum of the implemented system with the compensator. By sweeping over the design parameter, multiple design specifications are compared within achievable boundary of performances.
Subject
Proportional-Integral-Derivative ControlPID
Stabilizing set
Linear Control System
Computer-aided design
H-infinity optimal control
Optimal settling time
Optimal Dynamic Compensator
Citation
Han, Sangjin (2019). Robust and Optimal PID Controller Synthesis for Linear Time Invariant Systems. Doctoral dissertation, Texas A&M University. Available electronically from https : / /hdl .handle .net /1969 .1 /187160.