Application of Classical Controller Design Techniques to an Industrial Positioning System
Abstract
A positioning control system for an industrial application is designed and simulated for the use with a PID and loop-shaping controller. Classical design techniques are applied and their control performance under various conditions is assessed. The simulation is carried out under different input and disturbance conditions, as well as resonance mode additions. Keywords: PID controller; loop shaping, frequency response I. INTRODUCTION The methods of classical controller design, such as the celebrated frequency response method, have a well-established theoretical background. But their application in industry has been very sparse, save for the Proportional-Integral-Derivative (PID) controller which accounts for over 90% of all industrial controller applications. Here we use a real-world industrial positioning system to make a comparison between PID and loop-shaping controller design. Our approach is problemoriented, with the main focus on system performance, not the demonstration of what a particular control design is capable of. We want to compare controller performance under various inputs and disturbances, as well as the amount of tuning effort spent in obtaining the desired performance under the different conditions. This will give us a good idea of why the PID controller is so widely used in industry and a glimpse of how to excel it.
II. PLANT MODELING
The plant (figure 1) is based on a belt-and-pulley mechanism, driven by a DC motor. It is to move a load of 235lbs by 12 inches in 0.3 seconds with no overshoot. Plant and control saturations have been included in the model. Figure 1. SIMULINK Model of Plant From the plant model, a closed-loop PID control is constructed (figure 2). All the components in the plant simulation, including the parameters and saturations have been provided by Gao [1]. The closed-loop system design has been modified after Gao’s design. The modifications allow for different inputs and disturbances through simple manual switches. Figure 2. SIMULINK Model of Closed-loop Control
III. PID TUNING The PID
controller was proposed in 1922 by N. Minorsky [2] based on intuitive arguments of error feedback.

Download full report
http://cact.csuohio.edu/index.php?option...ad&gid=125