Stony Brook University

MEC 411

MEC 411 Lab # 1
Digital PID Speed Control of a Turntable
Sung Min Park ID 107047894
Jae Young Jang ID 108887378
Ki-Hoon Kim ID 106750344
Department of Mechanical Engineering
Stony Brook University
October 2, 2013
Table of Contents
Abstract
Introduction
Origin of PID Controller
Closed Loop Feedback Transfer Function
PID Turntable Speed Control system and the PID Transfer Functions
Experimental Procedure
Results
Discussion
Conclusions
Reference
Appendix
Abstract
In this laboratory experiment, an implementation of PID turntable speed
control system that satisfies certain performance specifications has been studied
and approached. The targeted objective specifications in the design are: Percentage
overshoot is to be less than 10%, Settling time to within 2% of the final value is to
be less than 500ms, and Rise time is to be less than 200ms. To satisfy such
specification, the input parameters, P, Ti, Td, (proportional, integral, and derivative
parameters) where adjusted manually to achieve the targeted state. This system
implementation required a building of an analog circuit of the PID controller
connected to a waveform generator and the DC motor with tachometer. Then, the
actual speed of the turntable was measured by the tachometer, which then its data
was collected through the DAQ to the computer. Finally, the experimental data
through manual controlling was observed and compared to the theoretical values
produced by MATLAB.
Introduction
Origin of PID Controller
A proportional-integral-derivative controller, as known as the PID controller, is
a generic control loop feedback mechanism widely used in industrial control
systems. As the name implies, a PID controller is a controller that includes elements
with those three functions. The proportional element is referred to as the “P
element,” the integral element as the “I element,” and the derivative element as
the “D element.” The PID controller was first placed on the market in 1939 and has
remained the most widely used controller in process control because of its
simplicity, cost-friendly, and the great usage in the industrial background. An
investigation performed in 1989 in Japan indicated that more than 90% of the
controllers used in process industries are PID controllers and advanced versions of
the PID controller. [1]
The way how it works is that it uses a feedback control method to analyze the
data, feed it back to the control, and analyze it more, and feed it again to the
control to maximize the stability.
Figure 1. Conventional Feedback Control System[1]
The basic structure of conventional feedback control system is shown in the
figure above using a black diagram representation. The Process (or called Plant) is
the object to be controlled. The purpose of control is to make the process variable y
to follow the set-point value r. To acquire this purpose, the variable u is changed as
the controller manipulates the input, r (in our case, the