Auto-tuning of PID controllers Mini course at Danfoss A/S Henrik Rasmussen Department of Control Engineering Aalborg University 11/13/2018 Auto-tuning of PID controllers

Auto-tuning of PID controllers Content The Satt Control auto-tuner in a distributed control system The Self-tuning Regulator concept PID-algorithm – textbook and modifications Ziegler-Nichols frequency response method Relay tuning in closed loop Bump-less transfer and anti integrator windup Gain scheduling Choice of controller type 11/13/2018 Auto-tuning of PID controllers

Auto-tuning of PID controllers References Automatic tuning of PID controllers, Åstrøm & Hägglund Adaptive Control, Åstrøm & Wittenmark Automatic tuning of PID-regulators, H. Rasmussen URL, http://www.control.auc.dk/~hr 11/13/2018 Auto-tuning of PID controllers

Auto-tuning of PID controllers 11/13/2018 Auto-tuning of PID controllers

Distributed control system 11/13/2018 Auto-tuning of PID controllers

SattControl Auto-tuner 11/13/2018 Auto-tuning of PID controllers

Auto-tuning of PID controllers Self Tuning Regulator 11/13/2018 Auto-tuning of PID controllers

Textbook and modified PID-algorithm The ''textbook'' version of the PID controller can be described by the equation Modification of ''textbook'' version 11/13/2018 Auto-tuning of PID controllers

Controller Parameters 11/13/2018 Auto-tuning of PID controllers

Ziegler-Nichols ultimate period method 11/13/2018 Auto-tuning of PID controllers

Auto Tuning based on relay feedback 11/13/2018 Auto-tuning of PID controllers

Auto-tuning of PID controllers Nyquist plot 11/13/2018 Auto-tuning of PID controllers

Phase and amplitude margin 11/13/2018 Auto-tuning of PID controllers

Auto-tuning of PID controllers 1. Break 11/13/2018 Auto-tuning of PID controllers

Auto-tuning of PID controllers Relay with hysteresis 11/13/2018 Auto-tuning of PID controllers

Auto-tuning of PID controllers Stable limit cycle 11/13/2018 Auto-tuning of PID controllers

Auto-tuning of PID controllers Offset 11/13/2018 Auto-tuning of PID controllers

Auto tuning of PID regulators Ziegler-Nichols tuning Spec. phase and amplitude margin 11/13/2018 Auto-tuning of PID controllers

Auto-tuning of PID controllers Actuator Saturation 11/13/2018 Auto-tuning of PID controllers

Auto-tuning of PID controllers Integrator windup 11/13/2018 Auto-tuning of PID controllers

Regulator modified to avoid windup 11/13/2018 Auto-tuning of PID controllers

Regulator modified to avoid windup 11/13/2018 Auto-tuning of PID controllers

Anti windup for PID controller 11/13/2018 Auto-tuning of PID controllers

Discrete time PI controller 11/13/2018 Auto-tuning of PID controllers

Auto-tuning of PID controllers p and q operators 11/13/2018 Auto-tuning of PID controllers

Discrete Time PID-controller 11/13/2018 Auto-tuning of PID controllers

Integrator windup and bumpless transfer 11/13/2018 Auto-tuning of PID controllers

Auto-tuning of PID controllers 2. Break 11/13/2018 Auto-tuning of PID controllers

Open loop step response 11/13/2018 Auto-tuning of PID controllers

Closed loop with PI control ?!? 11/13/2018 Auto-tuning of PID controllers

Anti integrator windup Measured actuator output Estimated actuator output 11/13/2018 Auto-tuning of PID controllers

Observer: A=1-exp(-Ts/(0.1*Ti)) 11/13/2018 Auto-tuning of PID controllers

Observer: A=1-exp(-Ts/Ti)) 11/13/2018 Auto-tuning of PID controllers

PI controller and a nonlinear valve 11/13/2018 Auto-tuning of PID controllers

Step response for different levels 11/13/2018 Auto-tuning of PID controllers

PI controller with gain scheduling 11/13/2018 Auto-tuning of PID controllers

Step response for different levels 11/13/2018 Auto-tuning of PID controllers

Gain scheduling principle 11/13/2018 Auto-tuning of PID controllers

Bumpless transfer between controllers y u y ref 1 A1 T1 G A1-R1 -S1 1 A2 T2 A2-R2 -S2 11/13/2018 Auto-tuning of PID controllers

Auto-tuning of PID controllers Choice of Controller 11/13/2018 Auto-tuning of PID controllers

Auto-tuning of PID controllers Conclusions The Self-tuning Regulator concept Relay experiment gives ultimate period and gain Ziegler-Nichols tuning Tuning based on phase and amplitude margin Bump-less transfer and anti integrator windup PID-algorithm – textbook and modifications Gain scheduling Choice of controller type 11/13/2018 Auto-tuning of PID controllers