Download Speed control of a DC motor - UTC Engineering Lab

Paper No: 349b
Web-based Unit Operations and Process Control Experiments
Jim Henry (speaker),
University of Tennessee at Chattanooga,
TN 37377
Eric Nuttall, Lomesh Dutta and Nader Vadiee
University of New Mexico,
Albuquerque, NM 87122
Keywords: Virtual laboratory, process control, MIMO systems, nonlinear control
Prepared for presentation at the Session 349 of Annual AICHE conference,
Nov 16-21, 2003
Copyright © 2003 Jim Henry, University of Tennessee at Chattanooga
Eric Nuttall, Lomesh Dutta and Nader Vadiee, University of New Mexico
AIChE shall not be responsible for statements or opinions contained in papers or printed in its publications
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Abstract:
What did we adopt from the Summer School? This paper describes the collaboration established between
the University New Mexico (UNM) and the University of Tennessee (UTC) at Chattanooga for the
development of internet operated chemical engineering labs. The close working collaboration developed
directly from contacts made at the Summer School. This paper describes how our School of Engineering
has developed an interdisciplinary web-based process control laboratory called the Coordinated Systems
and Control Laboratory. The CSC Laboratory provides lecture demonstrations for undergraduate systems
and control courses offered at EECE, ME and CHNE engineering school departments. This lab also offers
design and development projects for advanced undergraduate students in those departments. The CSC
laboratory helps students familiarize themselves with such software as MATLAB, MATHEMATICA,
CONTROL STATION, SIMULINK, and LabVIEW. The CSC Laboratory’s 8 Stations include:
* Rotary Pendulum system – Position Control
* Speed control of a DC motor
* Translational Inverted Pendulum System
* Three Tank System
* Magnetic Levitation System
* Rhino Robot Module
* LabVIEW Set-up
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Introduction
What did we adopt from the Summer School?
Laboratories are historically a key part of the chemical engineering curriculum but present many challenges
to fund, maintain and upgrade. I along with many Summer School faculty attended the sessions on
innovative laboratories and toured the modern laboratory facilities at the University of Colorado. It was at
the innovative laboratories sessions that I was first introduced to web based experiments and Professor Jim
Henry who is a leader in this technology and was presenting his work on web based laboratory
experiments. From Prof. Henry’s presentations, I was convinced that this approach was a true advancement
in how we operate laboratory experiments and students gain a laboratory experience. The ability of student
to access, operate, and control experiments at any location and at any time provides a unique learning
opportunity and takes us from the traditional fixed laboratory period to a new level and opportunity in
teaching the basic principles provided through the laboratory experience.
Hence the question for me was how to take this new laboratory approach back to the University of New
Mexico (UNM) where like many universities funds and resources for new efforts are limited. UNM was
fortunate to have a NASA funded project within our School of Engineering The NASA Pursue program
was committed to developing integrated laboratories primarily in process control that could be shared by
multiple departments. The NASA Pursue program became the home for my development of a three-tank
web based process control experiment and during the past year many web based process control
experiments have been developed. This was the start of extensive collaborations with Prof. Jim Henry.
This paper describes how the NASA purse program provided a basis for developing web base experiments
and details on the three-tank web based process control experiment which was developed as a collaborative
effort between the University of New Mexico (Eric Nuttall) and the University of Tennessee (UTC) (Jim
Henry)
Description of the NASA Pursue Program and the Web Based Laboratory
PURSUE is a program funded by NASA at the University of New Mexico (UNM) and its collaborating
higher education institutions, to build upon their funded research to augment the quality undergraduate
education in the fields of Mathematics, Science, Engineering and Technology (MSET) .The program aims
at strengthening the hands on research experience for undergraduates and high school students in these
fields and integrate the cutting-edge science and technology concepts into undergraduate curriculum , as
well as introductory-level courses and laboratories for majors and non-majors.
PURSUE engages all five School of Engineering Departments: Chemical and Nuclear Engineering, Civil
Engineering, Computer Science, Electrical and Computer Engineering, and Mechanical Engineering. Also
the program has participation from the departments of Biology, Chemistry, Earth and Planetary Sciences
(with the Institute of Meteoritics), Mathematics and Physics and Astronomy. The program has involved
more than 300 students, who have gained research experience in a multitude of projects. PURUSE also
hosts summer programs for high school students selected by NASA from all over the country where they
find an opportunity to be involved in research related activities.
The Coordinated Systems and Control Laboratory (CSC) has been developed as an innovative shared effort
between the NASA PURSUE program at UNM, its affiliated schools and the University of Tennessee at
Chattanooga (UTC) to capitalize on the synergism resulting from our similar interests. The approach
demonstrates an opportunity to share infrastructure and experimentation strategies amongst schools and
thus being able to enhance communication and collaborative research connecting them.
The CSC laboratory is an interdisciplinary web based process control laboratory that provides lecture
demonstrations for undergraduate systems and control courses offered at EECE, ME and CHNE
engineering school departments. This lab also offers design and development projects for advanced
undergraduate students in those departments. The CSC laboratory helps students familiarize themselves
with such software as MATLAB, MATHEMATICA, CONTROL STATION, SIMULINK, WINCON and
LabVIEW.
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The CSC includes the following experiments which are related to department outside of chemical
engineering but may in the future be of interest to chemical engineers.
Rotary Pendulum System-Position Control:
This experiment serves as an educational and research tool for a multitude of engineering fields. On one
hand where some simple experiments could be used to demonstrate important concepts of engineering
dynamics and the application of control systems in engineering design, on the other hand several advanced
experiments which cater the curriculum in frequency domain and state space control system analysis, real
time programming, linear and nonlinear control and intelligent control could be developed. The apparatus
is interfaced to the computer using WINCONTM real time. The system is fully compatible with
MATLAB, Simulink and Real-Time workshop. Currently, the web based control capabilities of the
system are being examined at both UNM and UTC.
Speed control of a DC motor:
The apparatus for this system consists of a Canon CKT26-T5 motor with tachometer, and is driven by an
Apex PA26 high power op-amp. This experiment is designed to help students of EECE and ME get
familiar with a variety of DC motor applications including conveyor belts, robotics, etc., where it is
important to maintain a constant speed under load variations. The experiment provides user the ability to
design control algorithms and compare their results with MATLAB simulations over the web.
Linear Inverted Pendulum:
The experiment is intended for students in Electrical Engineering to design and test their control algorithms
and attempt to stabilize an inverted pendulum mounted on a motor driven cart. This system stands as a
classical model of a nonlinear and unstable plant. Discrete time and fuzzy logic controllers for this system
were designed in LabVIEW that allow the students to input the parameters calculated by them and test the
stability of their own controller. The simulations were performed in MATLAB
Magnetic Levitation system:
The purpose of the experiment is to provide students a platform to design their controllers that could
levitate the ball from the post and to track the ball position to a desired trajectory. The posts also provide
repeatable initial conditions for control system performance evaluation. The apparatus was interfaced via
the MultiQ- PCI DAQ board and is controlled by WINCONTM real time software supplied by quansar, the
manufacturer of the system.
Rhino Robot:
The Rhino Robot provides a means for engineering students to develop controller systems capable of
directing each movement of the arm and thus use the robot in their respective tailored applications . The
system serves the curriculum targets each of CHNE, EECE and ME departments. Currently, several
improvements in the robot function including pressure sensing devices on the robot’s fingers for precision
controls, and visual sensing devices to distinguish between different objects for complex instructions are
being tested. The ability to control the robot over the internet is also being examined.
LabVIEW station:
Provides freshmen level undergraduate students an ability to familiarize themselves with LabVIEW using
instrument simulator cards.
Currently the status of the CSC is:

The laboratory is still being development. Though the three-tank system development, testing and
implementation is complete. Development and testing required about one year.
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 The NASA funding for this program is in final stage.
 The costs for hardware and software maintenance are hardware and software is high.
The lab also requires at least two assigned Teaching Assistants to manage the lab equipments and online
facilities.
Description of the Three-Tank Process Control Experiment
The control of non linear systems, particularly multi-variable systems, plays a very significant part in the
advancement of automation of technical processes. One of the classic examples of such systems is a “Three
Tank System” as illustrated in Figure 1. This experiment presents an excellent test bed for nonlinear system
decoupling and control.
The basic apparatus consists of three interconnected plexi-glass tanks numbered from left to right as tank 1,
tank 3 and tank 2. All three tanks are connected with the third tank in series, tank 2, which drains to the
system exit. Liquid is pumped into the first and the third tanks to maintain their levels. The level in the
middle tank affects the level in the two end tanks. Each tank is fitted with a static pressure sensor, which
gives a voltage output proportional to the level of liquid in the tank.
.
Figure 1 Schematic diagram of the three tank system
There are six manual valves v1, v2...v6 that can be used to vary the configuration of the process or to
introduce disturbances or faults. Two variable speed pumps driven by DC motor are used in this apparatus.
These pumps are designed to give an accurate well defined flow per rotation. Thus, the flow rate provided
by each pump is proportional to the voltage applied to its DC motor. Q1 and Q 2 are the flow rates of liquid
into tank1 and tank2. The apparatus is interfaced to a computer using the National Instruments, DAQ 6024E data acquisition card. This DAQ card allows for sampling of 16 separate differential analog inputs and
provides with 2 analog outputs. With this setup it is possible to control the apparatus via any computer on
the internet thus enabling students to have round the clock access to the experiment.
This experiment serves as an excellent test bed for non linear multivariable process control problems. The
control of liquid levels in such systems is particularly common in chemical process industries. The
experimental procedures are designed according to the curriculums of the Chemical, Mechanical and
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Electrical engineering as the apparatus provides the capability of level control, nonlinear system decoupling
and designing of control algorithms and thus holds special interests to each of these fields. The basic
apparatus consists of three interconnected plexi-glass tanks connected in series. Two variable speed
diaphragm pumps capable of providing an accurate well defined flow per rotation are used to feed the two
tanks on the either side. The middle tank helps in controlling their levels to the desired set point as
specified by the user. Each tank is fitted with a static pressure sensor, which gives a voltage output
proportional to the level of liquid in the tank. Each tank is fitted with a static pressure sensor, which gives a
voltage output proportional to the level of liquid in the tank. The students in LabVIEW TM environment
performed the data acquisition and the implementation of a PI controller as illustrated in Fig. 2 showing the
web based controller window. The experiment also allows the user to compare the results obtained with the
simulation program developed in SimulinkTM and MathematicaTM.
Figure 2: Three tank system in PI control mode on the web
Summary
The Summer School provided an opportunity to learn about a new approach to laboratories and
collaboration with a colleague that had many years of experience in this area. Several web based process
control experiments have subsequently been developed and are being integrated into the undergraduate
curriculum. We are still learning how to introduce students to these experiments and maximize their
educational benefits.
Challenges of continued funding and staffing of the Coordinated Systems and Control Laboratory are
being addressed through the Dean of Engineering and the Department Chairs.
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References
1. Franklin, G.F., J.D. Powell, and A. Emami-Naeini, Feedback Control of Dynamic Systems, 4th ed., NJ:
Prentice-Hall, 2002.
2. Phillips .L., and R.D. Harbor, Feedback Control Systems, 2nd ed., NJ: Prentice-Hall,
1991.
3. Three-Tank System, DTS200 Practical Instructions, 1996
4. PI Control of the "Three tank System" Alireza Naddaf, Lomesh Dutta, (submitted to IEEE, Summer,
2003)
5. PI control of "Three tank System" -- Alireza Naddaf, Lomesh Dutta et al report submitted to NASA
pursue, April 2003
Acknowledgements
We wish to thank the organizers, sponsors and hosts of the ASEE Chemical Engineering Summer School
2002.
UNM work in the Coordinated Systems and Control Laboratory has been supported in part under the
PURSUE Project at UNM with grants from NASA.
UTC's Center of Excellence for Computer Applications has supported this effort with a generous grant.
Other support has been received from the UTC College of Engineering and Computer Science and National
Instruments. Partial support for this work in the lab is being provided by the National Science Foundation's
Division of Undergraduate Education, Instructional Laboratory Improvement (ILI) grant DUE #97-51024.
Biographical Information
ERIC NUTTALL
Eric Nuttall is Professor of Chemical and Nuclear Engineering at the University of New Mexico. He directs
graduate student research on in situ bioremediaiton as well as teaches an annual course on bioremediation.
NADER VADIEE
Nader Vadiee is the director of the PURSUE Program in the Engineering College at UNM. He is an
associate professor in the Department of Electrical and Computer Engineering at the University of New
Mexico. He was also a consultant for New Mexico Engineering research institute (NMERI) at the
University of New Mexico, responsible for the "Standby power plant study" project conducted for
Cheyenne Mountain Air Force base (CMAFB), Colorado Springs, Colorado.
LOMESH DUTTA
Lomesh Dutta is a graduate student in the Chemical and Nuclear Engineering Department at UNM.
JIM HENRY
Jim Henry is Professor of Chemical and Environmental Engineering at the University of Tennessee at
Chattanooga. He has also taught at Tulane University, Prairie View A&M University, the University of
Jordan in Amman and the University of Edinburgh. Dr. Henry received his Ph.D. from Princeton
University. His B.S.Ch.E. was received from Rice University. He completed a postdoctoral year at Yale
University. Dr. Henry has also worked for a U.S. Department of Energy research lab, DuPont Company
and Chevron Oil. For the past 12 years, he has focused on developing data acquisition and control
application in laboratories for controls systems, chemical and environmental engineering. He also teaches
the courses in principles and in design of chemical and environmental engineering processes. His research
is in the area of applied control systems and distillation control.
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