# Digital Control 2000: Past, Present and Future of PID Control

**Proceedings of the IFAC Workshop, 5-7 April 2000, Terrassa, Spain**

**By**

- J. Quevedo
- T. Escobet, Automatic Control Department, Universitat Politecnica de Catalunya, Campus de Terrassa, Rambla de Sant Nebridi 10, 08222 Terrassa, Spain

At the beginning of the new millennium the PID controller continues to be a key component of industrial control. During this century many different structures of control have been proposed to overcome the limitation of the PID controllers. Because of their simplicity and usefulness, they give a very useful solution to an important part of the industrial processes.

The present-day structure of PID controllers is quite different from the original analog PID controllers. Now the implementation of the PID is based on digital design, these digital PIDs include many algorithms such as anti-wind-up, auto-tuning, adaptive, and fuzzy fine tuning to improve their performances, but the basic actions remain the same.

During the last two decades, the general reluctance of researchers to use PID controllers has begun to disappear. Many of the new capabilities of digital PID controllers have been introduced by the research community. The industrial control users apply these innovations easily, even enthusiastically. PID control has become one of the most important ways for the scientific specialist in control and the users of industrial control to work together.

This workshop was organized so that the scientific world and the industrial control world could meet and discuss the present and future use of PID controllers - the successes and failures of their use and how to determine the limits of performances. This workshop was also useful for learning about control history, since the origin and evolution of PID control can provide us with keys for new development and designs.

### Audience

For researchers working towards industrial applications of PID controllers and technologists interested in applying PID controllers in novel situations.

### Book information

- Published: October 2000
- Imprint: PERGAMON
- ISBN: 978-0-08-043624-1

### Table of Contents

**Keynote Papers**. The Past of PID Controllers (S. Bennett). PID-Deadtime Control of Distributed Processes (F.G. Shinskey). The Future of PID Control (K.J. Åstrom, T. Hägglund).

**New Structures And Design of PID Controllers I**. A Repetitive-PD Controller for a Low Order Industrial Plant (R. Costa-Castelló, R. Griñó). PID Robust Model Following Control (S. Skoczowski, S. Domek). A Different Approach to PID Design (K.A. Stillman). On Fractional PID Controllers: A Frequency Domain Approach (B.M Vinagre et al.). A Neuro PID Controller for Complex Dynamic Plants (Q.M. Zhu, K. Warwick). Design of PID Controllers via Frequency Response Approximation (S. Pegel, S. Engell).

**Tuning Rules for PID Controllers**. A Reference Guide to PID Controllers in the Nineties (M. Lelić, Z. Gajić). Automatic Tuning of PID Controllers for MIMO Processes (H. Ono et al.). Control Design for PID Controllers Auto-Tuning Based on Improved Identification (R.R. Pecharromán, F.L. Pagola). Two-Degree-of-Freedom PID Controllers - Their Functions and Optimal Tuning (H. Taguchi, M. Araki). A Complement to Autotuning Methods on PID Controllers (R.F. Garcí, F.J.P. Castelo).

**Electrical Applications of PID Controllers**. Design and Tuning of PI Velocity Regulators for High Performance Drives (J.M. Guerrero et al.). Nonlinear Multivariable Speed and Flux PI Control of Induction Motors (M.K. Maaziz et al.). Modelling and PID Control of a Rotary Dryer (F.R. Rubio et al.). The Generalized PID Controller and Its Application to Control of Ultrasonic and Electric Motors (I. Rusnak). Digital Servo IC for Optical Disc Drives (T.H. Akkermans, S.G. Stan).

**Tuning Methods of PID Controllers**. Nonmodel-Based Explicit Design Relations for PID Controllers (R. Gorez, P. Klàn). Robust Automatic Tuning of an Industrial PI Controller for Dead-Time Systems (A. Ingimundarson, T. Hägglund). Methodologies for the Tuning of PID Controllers in the Frequency Domain (F. Morilla, S. Dormido). Auto-Tuning PID Controllers in Terms of Relative Damping (F. Morilla et al.).

**Poster Papers**. A Summary of PI and PID Controller Tuning Rules for Processes with Time Delay. Part 1: PI Controller Tuning Rules (A. O'Dwyer). Benchmark Systems for PID Control (K.J. Åstrom, T. Hägglund). Self-Tuning PID Controllers Based on Dynamics Inversion Method (V. Bobál et al.). DIRAC: A Direct Adaptive Controller (R. De Keyser). Co-Evolutionary Design of PID Control Structures (P.B. de Moura Oliveira, A.H. Jones). Alternative to Adjust the Rule Base on Rule Based Controllers (R.F. García et al.). Bifurcation Analysis of Indirect Field-Oriented Control of Induction Motors (F. Gordillo et al.). Adaptive Design of PID Controllers Based on an Alternative Method to Root Locus (M. Martínez et al.). Plant Driven Design of a Nonlinear PID Controller (R. Neves Da Silva). A Summary of PI and PID Controller Tuning Rules for Processes with Time Delay. Part 2: PID Controller Tuning Rules (A. O'Dwyer). Fuzzy PD Control of an Unstable System (M. Olivares, P. Albertos). Cross-Optimization Aspects Concerning the Extended Symmetrical Optimum Method (S. Preitl, R.-E. Precup). Discrete-Time Model Reference Feedback and PID Control for Interval Plants (F. Takemori, Y. Okuyama). Oxygen Control of Bioreactor Model Using Fuzzy Processed PID Controller Outputs (D. Vrečko et al.). Understanding the PID and Its Tuning (E.H. Bristol). Some Considerations About the Refinements and the Accuracy of PID-Controllers (D. Popescu et al.). Controller Tuning for Controlled Plants with Time Delay (M. Vítečková et al.). Simple PI and PID Controllers Tuning for Monotone Self-Regulating Plants (M. Vítečková et al.).

**New Structures and Design of PID Control II**. PID Tuning for Loop Decoupling of Multivariable Systems with Uncertainty (I. Egaña, M. García-Sanz). A New Tuning of PID Controllers Based on LQR Optimization (R. Argelaguet et al.). Design of PID Controllers Using Multiobjective Genetic Algorithms (A. Herreros et al.). PID Controller and LQ Control Design (J. Mikleòš et al.). Robust PID-Like Controllers - Design and Tuning (R. Prokop et al.).

**Supervision of PID Controllers**. Relay Feedback Experiment for Coulomb Friction Identification (A. Besançon-Voda, P. Blaha). Software Enhancements Improve Usefulness of a PI(D) Self-Tuning Application (A.F. Doonan et al.). Fault-Tolerant PID Controllers Using a Passive Robust Fault Diagnosis Approach (V. Puig, J. Quevedo). Model Fault Detection of Feedback Systems: How and Why to Use the Output of the PID Controller? (J. Quevedo et al.). Near Optimal Tuning Rules for PI and PID Controllers (B. Kristiansson, B. Lennartson).

**Industrial Control Applications I**. A Distributed PID Controller for an Injector Powered Transonic Wind Tunnel (F. Corrarou et al.). A PID Control Scheme for Trajectory Simulation in High Enthalpy Test Facilities (M. Naddei et al.). PID and Non-Linear Controllers for Power Hydraulic Turbines (O. Quiroga et al.). Reuse- and Object-Oriented Development of Standard Control Algorithms (J. Schäfer, L. Litz). Control of a Cryogenic Process Using a Fuzzy PID Scheduler (M. Santos et al.). Optimal Control Strategies for Imaging Using Formation Flying Spacecraft (F.Y. Hadaegh, M. Mesbahi).

**Optimal Tuning of PID Controllers**. Tuning of PID Controllers: An Optimization-Based Method (C.A. Neto, M. Embiruçu). Derivation and Tuning of PID Controller via Output Tracking Direct Gradient Descent Control (K. Shimizu, E. Denda). Interval PI Velocity Control of a Non-Holonomic Mobile Robot (J. Vehí et al.). Magnitude Optimum Tuning Using Non-Parametric Data in the Frequency Domain (D. Vrančiz et al.). A General Approach to PID Optimal Design: Achievable Designs and Generation of Stabilizing Controllers (R. Vilanova et al.).

**Industrial Control Applications II**. PID Dual Loop Control for Industrial Processes (R.M. De Santis). From Adaptive PBC to PI Nested Control for STATCOM (G. Escobar et al.). LS-3000 Digital PID Controller (J. Pi-Mira et al.). Returning PID Temperature Controller for an Unstable Gas-Phase Polyolefin Reactor (H. Seki et al.). Tuning of a pH Control Loop in a Kaolin Mining Process (B.S. Torres et al.).

**Adaptive and Tuning of PID Controllers**. Robust Adaptive PID Controller Tuning for Unmeasured Load Rejection (P.D. Hansen). Adaptive PID Controller with On-Line Identification (J. Macháček, V. Bobál). A New On-Line PID Tuning Method Using Neural Networks (A.B. Rad et al.). Tuning of a Adaptive Power System Stabilizer by a Fuzzy Logic Based Supervisor from a Local Model Network (C.T. da Costa Jr. et al.). Adaptive Tuning of Fuzzy Set-Point Weighting for PID Controllers (A. Visioli).

**Complex Systems and New Structures of PID Controllers**. FIR Differentiator Based on a Polynomial Least Squares Estimation. Application to PID Control (J. Colomer, J. Meléndez). From PID to Model Predictive Control: A Flatness Based Approach (R. Marquez, M. Fliess). Model Reference PI Control of a Multivariable System with Saturation - A Case Study (P. Stewart, V. Kadirkamanathan).

**Tuning and Self-Tuning of PID Controllers**. Simulation and Pilot Plant Trials Aid Commissioning of Neuro Self-Tuning PI Controller (T.J. Böhme et al.). Relay Feedback Identification Under Imperfect Actuator (Y.C. Cheng, C.C. Yu). PID Self Tuning Algorithm for Industrial Compact Controllers (J. Hücker, H. Rake). PID Control for a Distributed System with a Smart Actuator (D. Lee et al.). PID - Gain Scheduling Controller for a Robot Manipulator (C. Pérez et al.). Self-Tuning PID Controllers Based on the Strongly Stable Generalized Minimum Variance Control Law (T. Sato et al.).

**Performances of PID Controllers**. Describing Function Method for Stability Analysis of PD and PI Fuzzy Controllers (J. Aracil, F. Gordillo). On Optimizing PID Controllers for Uncertain Plants Using Horowitz Bounds (C-M. Fransson et al.). A Comparison of Stability and Performance Robustness of Multivariable PID Tuning Methods (M.R. Katebi et al.). Robust Design of PID Controllers Through the Randomised Approach (J. Serrano et al.). Implementation of High-Performance PID Controllers Using RNS and Field-Programmable Devices (L. Parrilla et al.).

**Learning and Tuning of PID Controllers**. Iterative Feedback Tuning of a PID in a Pilot Plant (R. Mazaeda, C. de Prada). Design and Experimental Evaluation of Self-Tuning PID Controller Using Evolutionary Computation (Y. Mitsukura et al.). Robust PID Tuning. Application to a Mobile Robot Path Tracking Problem (J.E. Normey-Rico et al.). A Design of Self-Tuning PID Controller with a Time-Delay Compensator (Y. Ohnishi et al.). Tuning Fuzzy PI Controllers by Iterative Learning (V. Villagrán, D. Sbarbaro). Fuzzy Logic Based Tuning of PID Controllers for Plants with Under-Damped Response (A. Visioli).

**General Contributions to PID Control**. A New Ratio Control Structure (T. Hägglund). Optimal-Tuning PID Control for Industrial Systems (G.P. Liu, S. Daley). RaPID: The End of Heuristic PID Tuning (P. Van Overschee, B. De Moor). Tuning PID Controllers for Minimizing ISE and Satisfying Specified Gain and Phase Margins (J.-H. Hwang et al.).

**Author Index**.