- Email: [email protected]
Mechatronics Education at the University of Illinois
MECHATRONICS EDUCATION AT THE UNIVERSITY OF ILLINO...
14th World Congress ofIFAC
Copyright © 1999 IFAC 14th Triennial World Congress, Beijing, P_R_ China
M-6a-Ol ~l
MECHATRONICS EDUCATION AT THE UNIVERSITY OF ILLINOIS Mark W. Spong and Tsu-Chin Tsao
lJniverS'ity of Illinois at Urbana-Champaign, Coordinated Science Laboratory, 1308 Ut~. Afain Str"cct, Urbana, lL~ 61801, [13...4 , [email protected]
Abstract. This paper describes the development of the College of Engineering ~VIecha tronics Labora.tory at the "Cniversity of Illinois and an associated course~ Introduction to A1echatronicB. The Jvlechatronics Laboratory is a shared facility in our College of E,ngineering~ part of the network of shared laboratories that we have developed to support courses in dynamics and control systems at the University of Illinois. The course a.nd laboratory are designed to give students practical experience in computer interfacing, real-time prograrnming, sensing, actuation, and control system design, as well as to serve as a springboa.rd to higher level concepts in dynamics and intelligent control~ such aH nonlinear and hybrid control, Inachine learning, fuzzy logic, neural networks, and discrete-event systems. Copyright © 1999 IFA(~
Keywords. mechatronics, control
education~ real-time
1. INTRODUCTION
rv1echatronics is often described as the synergistic integration of electrical engineering, COlllputer science, electronics~ rnechanical enginecring~ and control engineering (Fraser and Milne, 1994; Bolton, 1995). One may also think of IVlechatronics more concisely as '~putting intelligence onto physical systems." It is this second definition that drives our philosophy in the developInent of the IVlechatronics Lahoratory and the course, Introduction to Mechatronics. Definitions of '"intelligence" often include phrases like "the ability to learn" and Hthe ability to cope with new situations. (Webster's New \Vorld Dictionary, 1990). The advancements in microprocessor and sensor technology, occurring at an ever increasing pace, allow engineers to design electra-mechanical systClns that collect and process sensory data and respond in conlplex ways that can be said to mimic biological intelligence. l\1echatronics involves the design of such electro-mechanical systems.
Copyright 1999 IFAC
systems, embedded systems
Applications of Inechatronics engineering are myriad, including robotics and lllanufacturing systems, automotive and aerospace systems, everl household appliances and consumer electronics. The Mechatronic design engineer must be able to integrate diverse disciplines of engineering and must adapt to the rapidly changing technology that is continuously opening up new application areas. For example, the relatively new field of !\1E,!v[S (I\t1icro-Eleetro-!vlechanical Systems) offers tremendous potential for new applications but, at the same time, requires mechanical engineers to understand design issues at scales where quantum effects are important, and requires electricaJ engineers to understand new developments in materials science and so Oll.
This paper describes the development of a Mechatronics Laboratory and a course, Introduction to Mechatronics at the lTniversity of Illinois. The course and laboratory are designed to give students pract.ical experience in cornputer interfacing, real-time programrning, sensing~ actuation, and control system design, as well as to
6359
ISBN: 0 08 043248 4
MECHATRONICS EDUCATION AT THE UNIVERSITY OF ILLINO...
14th World Congress ofIFAC
serve as a springboard to higher level concepts in dy-
nalnics and intelligent control) such as nonlinear and hybrid control, machine learning, fuzzy logic neural net",,"orks, and discrete-event systerns. 1
2. THE LABORATOR).r NETWORK The rv1echatronics Laborat.ory is part of the network of shared laboratories that we have developed to support courses in dynamics and c.ontrol systems at the University of Illinois. In addition to the lVlechatronics Laboratory, our laboratory network consists of
The Mechatronics Laboratory contains eight funy equipped Vv·orkbenches to enable the design and realization of mechatronics projects. The laboratory also contains an active noise cancellation system and an active vibration control system, both produced by Digisonix, Inc.
4. THE COURSE DESCRIPTIC)N The course, Introduction to Mechatronics.. was offered during the Spring semester 1998 and cross-listed in the Departments of General Engineering (GE 393), and IVIechanical & Industrial Engineering (lE 393). The course is also listed as part of our ~lan\lfacture Engineering degree option program as MfgE 330, Interfacing .Alethods for Manufacturing Systems. Thirty students students eompleted the class in Spring, 1998.
(1) The College of E,ngineering Control Systems Laboratory, which we refer to as The Core Lab, (2) The Robotics and Automation Laboratory, (3) The Fluid Po~ver Laboratory, and (4) The Flight Control Syst.ems Laboratory. The Core Lab Vlas developed starting in 1994 to serve as a centralized facility replacing exisiting departmental laboratories and servicing all of the basic courses in feedback control systenls in the College of Engineering. By elevating our laboratory instruction froln the Departrnent level to the College level~ v.re are able to eliminate v..~aste and duplication~ hire a full-time lab manager, and keep the hard\vare and software up-to-date, while allowing the individual Departments to retain autonomy of their curricula. The four additional labs are referred to as Satellite Labs and are viewed as second-level laboratories to service courses in the various Departments that follow the introductory controls courses, such as courses in R,obotics, Mechatronics, Hydraulics~ and Flight ControL All of the labs are shared by the va.rious Departments in the College and are supervised by a committee of faculty whose interests lie in dynamics and control. Our shared laboratory concept is described more fully in Alleyne, et.al.~ (1996).
4.1 Topical Outline: The class consists of a single lecture section meeting twice per week together v;tith multiple laboratory sections~ each. meeting once per v.reek. The lectures are primarily devoted to the "higher level" issues such as system modeling and design, sensor and actuator dynamics~ and intelligent control theory, while the laboratory sections provide hands-on exposure to issues of computer interfacing) including interrupts, timing, real-time programming, and signal conditioning and include final design projects involving teams of students. The topical outline of the course i~ as follows:
L~-\B
3. THE 1\1ECHATRONICS
(3) $125,000 allocated from a $l~OOOlOOO grant by the General Motors Leadership Enterprise in "VIrtual Education Research (G~I-LE\'ER) PrograIIl (19972002).
The Mechatronics Laboratory \vas made possible by COIUbining resources {roln existing facilities new initiati ves ~ t
and generous external support. This includes" (I) Equipment from an existing course on Interfaeing ~1et.hods for Nlanufacturing Systems (i\1FG330j IE393) established in 1990 with support from General 1\110tors Computer Integrated Nlanufacturing: Education Program, (2) A $125~OOO gift from John Deere (1995-2000) to support ne\v initiatives in real-time control and mcchatronics education,
(1) Introduction (a) 'Vhat is l\1echatronics? (b) Mechatronics Design Philosophy (c) Examples of l\1echatronic Systems (2) Sensors (a) sensor terminology (b) static and dynarnic characteristics (c) position sensing (d) velocity and acceleration nH~al;urelnent (e) proximity sensing (f) strain gauges (g) force and pressure sensing (h) temperature sensing (i) filtering and signal eonditioning (3) Electric .Actuators (a) DC-motors (b) AC-motors
6360
Copyright 1999 IFAC
ISBN: 0 08 043248 4
MECHATRONICS EDUCATION AT THE UNIVERSITY OF ILLINO...
(c) Stepper rIlotorR (d) Brushless DC-motors Cc) motor control (4) Hydraulic and Pneuluatie Actuators (a) basics of hydraulic and pneumatic systems (b) control valves (r:) electro-hydraulic systems (cl) electra-pneumatic systems (5) Analog and Digital Electronics (a) transistor and diode circuits {b) operational amplifiers (c) inst rumentation anl plifiers (d) AID and D/.L~ converters (e) Power Rupplie~ (6) Computer Interfacing (a) Hardware and software organization Cb) Computer interfacing for analog and digital input/output devices (7) Real-time Systems (a) Soft and hard real-time systems (h) COluputer interrupts (c) Prioritized preemptive multi-tasking (cl) CPU timing diagram and loading factor (e) Progralnlnahle interval timers (f) System behavioral analysis: state transition di. agram and state chart (8) Systenl ~1odeling
assignrnents. The laboratory and project topics are as follows: Lab 1: Getting Started with C: An introduction to the computer and instrumentation, software environlnent~ and C prograrnming. Lab 2: Digital I/O: Cornpllter int.erfacing, LED and mechanical s\\Titches. Project 1: Simulation of a bank teller machine operator interface in C. Lab 3: .A.nalog I/O: AID and D/..~ interfacing, micromachined strain gage force and pressure sensors~ and signal conditioning circuits_ Lab 4: DC Motor Speed Control- Proportional Control Lab 5: Timer Interrupt~: cornputer interrupt generation and thermoelectric heat pump actuators Project 2: E·mulation of an automotive cruise control using a DC motor and I/O rnodule. Project 2 requires rnodification and integration of Labs 2-4. Lah 6: DC motor PI control using a timer interrupt. Incremental encoders and encoder interfaces. Lab 7: l\1ultiple soft~rare tinlers and external interrupts. piezoelectric switch, optical switch, and debouncing circuits for triggering external interrupts. . Lab 8: Stepper motor control: stepper motor operatIng principles, motor wiring~ pulse/frequeney generation software, and testing of maximum start-up torque and slewing speed. Project 3: Real-time monitoring and control of a machine tool spindle, emulated on the DC motor and I/O module. Project 3 requires modification and integration of Labs 5-7. Lab 9: Binarv state actuators and pO~'er control: clectromagneti~solenoids, shape memory alloy actuators, and power s,\\'itching lllodules. The software used for timer interrupt and lllultiple software timer is adopted from Auslander and Tham (1990).
(a) li near a.nd non] inear systems (b) cq uilibria and stability (c ) lincarization (9) Classical and ~1odern Control (a) transfer functions and block diagrauls (b) state space systems and realizations (c) Controllability and 0 bservabili ty (d) Digital Control (e) Pole Assignment and Optima.] Control (f) Observers (g) Duality and the Separation Principal (10) Intelligent Control Ca) Fuzzy Logic and Fuzzy Control
6. FIN.A.L PROJECTS
(b) Neural ~ctworks (c) Dis~rete Event SystelDS
Students form teams of t\vo or three persons and create their ov.rn final projects. The final project guidelines require that. the soft.ware nlllst have a real-time comput~ng component and the hard\vare must explore somethIng not covered in the regular labs. For the Spring 98 class, the projects chosen by the students were:
(cl) Logic-Based S\vitching Control
5.
L.tI\B()RATOR:Y~
INST'RUC'TION
The laboratorv instruction consists of nine laboratories and three regular projects during the first 11 weeks of the semester, and a final project during the last 5 weeks of the seInester. The three regular projects are designed such that students must modify and integrate softwarejhard\vare components covered in the previous weekly laboratory nlaterials to accomplish the project
Copyright 1999 IFAC
14th World Congress ofIFAC
(1) (2) (3) (4) (5) (6) (7)
.Lo\ 2-D light tracking system. A ski-jump ball bearing catcher. .A. programmable length paper cutter. An electronic cam motion system. .LA-. smart traffic c:.ontroller. An automatic guitar tuner. A robotic material sorter based on height.
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ISBN: 0 08 043248 4
MECHATRONICS EDUCATION AT THE UNIVERSITY OF ILLINO...
(8) A ball and beam balancing system. (9) .A. noise and vibration cancellation DSP module using the Digisonix hard\varc.
14th World Congress ofIFAC
C~-program
6.1 Selected Project Abstr'act.s BeloVv~ are reproduced a subset of the projec.t. abstracts fronl the student final reports together "\vith photos of SOlnc of the projects. For the complet~ liRt of projects and their abstracts, the reader may consult the, class ,,""ebsite at http;l/robotO.ge.uiuc.edu/~spong/mechatronics~
• Project 1: Ball Bearing Catcher Fig. 2. Electronic Cam Profile Generator paper on Vv"hich the ca:rn 1S being drawIl~ The different angular positions of the paper ca.n be aehieved using a stepper lnotor. l)he different radial positions of the peneil ean be achieved by at.taching the pencil to a linear motor. Thus a suitable soft~ ware control has to be developed to control a linear motor, and hardware caonfiguration is to be set up for canl profile generation. The HysteIll has to be flexible for different types of cam profile generation. This includes variations in rise, fall 7 dwell angle, as well as rise and fall profileH, i.e. linea.r, parabolic, etc. R,obust implementation is required so as to bH able to generate cam profile at high speeds (60 rpm) . • Project 3: 'I'he Dalancing.~et
Fig. 1. Ball Bearing (jatcher ~ ()nly the ramp is sho\vn here. Not. sho\vn is the cart. vvhieh IllOVPS along the floor to catch the ball rolling off the ramp. Ab8t'l"(lCl: l.'his project involves the design of a ramp and a ball bearing catcher. Jot\. steel ball rolls do~~n a ski-jump shaped ra-nlp and thp tinH~ it takes for the ball to pass bet,veen two switches on thf: dov,rn\vard ~dope is llleasured. rfhe ball flies off the end of the ramp and a cart at the end is llloved to a position to catch it calculated in real tirrle. T\vo optical sv.ritches are used as hardware interrupts and are switched \vhen the ball passes by thelTI. l'he cart is mounted on a belt which iH controlled by a stepper InotOl". 'I'his project involves the use of hardvlare interrupts, digital i/o~ analog output~ and
open-loop control. • Project 2: Electronic Canl Profile Generator using Linear Actuator & L\/D'l' .Abstract: The nlain objective of this project is to develop an electronic cam profile generator..A. ca.n) can be generated by moving a penf:il raJiially to different positions at different angular positions of the
Copyright 1999 IFAC
,Fig. 3. Ball and Bealu Systerll
Abstract: l he 109S American Cont.rols Confernee CA.CC) presented the following design project as student competit.ion: balance a ball on abeam by changing the angle of the bearn under the ball. The 1
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ISBN: 0 08 043248 4
MECHATRONICS EDUCATION AT THE UNIVERSITY OF ILLINO...
14th World Congress ofIFAC
design project ~~as entirely theoretical. Each student received a SIl\.1UI.lINK rTlodel of the phyHical system, and the. controller design and testing \vas based entirel~'( on this oroclel. Because 'vc already had the ban, motor, a.nd sensors available, we decided to physically implement this design. Our goal in designing and building this system was to pro~ vide a t(-~stbed for future students to develop their o\vn controllers or sensors. • Project 4: Real-Time Control Sinlulation of an r\ntiLock Braking Systenl (ABS)
Fig. 5. 2-D Light 'Tracking System
axeH. The ohjective here \vas to achieve tracking in real time. 'I'hus, systern response tilnp, for sensing the light and subsequent control of the motors to track the light are of vital inlportancc. Four light sensors v.rere used in this project and they ~~ere oriented perpendicualr to each other in such a way that the relative magnitude of any two sensors deterlnineH the direction in which a particular OlD--tor needs to be moved to track the light HourCf~. A setup like this could find applicatinos in solar panels where the orientation of the panels needs to be ehanged during t.he course of the day to ensure that light al\vays falls .normal t.o the panels~ thereby ensuring the rnaximum energy is generated by the panels. Fronl L,an1bert~s cosine law~ v\"e kno\v that thp., intenHity of light falling on a surface is proportional to the cosine of the angle bet,~.reen the Ilorrnal
Fig. 4 ..A.BS sirnulatoI'. The t~r() Inotors Hlust be synchronized in such a way that the basketball rolls about a single axis \\rithout "\vobbling.
This project entails the shnulation of an antilock braking systenl (A•.BS) cllrrently available on a grov,ring nunlber of passenger cars and commercial vehicles. 'I'he ABS will ensure that during severe braking the wheel velociti8g are at all tilnes p,quiva.lent in order to prevent the ocurence of ","'heel lockup~ skidding 1 or s\vaying. In this project., t"vo nlOt.on~ are utilized for th8 indiyidual control of a set of wheels. Eaeh wheel is equipped with a proportional plus integral (PI) controller as is the velocity regulator ~ intended to equilibrate the wheel velocities upon initialization of a situaitioIl resembling lock-up. The performance of the A.BS systerrl IIlay be adjudged by either the real-tinle visualization of a ball-rotating apparatus, or throu~h graphical d(-~piction subsequent to data acquisition. Both opt.ical encoders and t.achometers are Inounted to the two motors to facilitate feedbaek control. • Project 5: Autonlated Light rrracking Systenl Ab"dr·act: The ainl of this project "vas to develop a light, tracking system by t,vo axis Inotor eontrol. ~t\ny light source present in a hernispher~ can be tracked by 180 degree rnotion of t\VO perpendicular
to the plane and the light source. Thus~ irnproper alignrnent of t.he panels could lead to drastic red llCtion in the energy that is captured by the panels. One could also think of other applications for this simple t\VO axis control in which the signal source is SOlllething other than light, e.g;. tculpcrature or Illagnetic field as in radars or other navigat.ional equipment where one needs to trak a given energy source by continuously ll1onitoring the sig;nal and orienting an axis \vith respect to the current position of the energy source. • Project 6: Simulation of Smart Traffic Lights .4 bstract: T'he goal of this project is to simulate "~rnart" traffic lights. ,~ SInarf~ lights are traffic .s-ignals that are able to sense the f}(HV of traffic, and thus can cont.rol the length of their varjous traffic commands. In this simula.tion, steel balls rolling down t~TO intersecting tracks simulate various traffie. eonditions on lnterspcting road"vays. T\vo pic~~o-
6363
Copyright 1999 IFAC
ISBN: 0 08 043248 4
MECHATRONICS EDUCATION AT THE UNIVERSITY OF ILLINO...
14th World Congress ofIFAC
electric sensors are used to sense the approach of the traffic (balls), and et C prograrrl controls the traffic si?;oals. The project is also augmented ~~ith additional features, such as an emergency vehicle s'\Jrritch. The prograIn is conlpatible with the IB!vIPC hardware platform. The team successfully developed and implemented a system for the simulation of thfl ~'Slllart" lights. The traffic lights are triggered by the balls rolling throught the piezo-eleetric switches. A stepper motor is also used to st.op the balls in the direction of the red light. Finally, there are LED lights that indicate \\I'hich traffic light is red.
7.
.L~SSESS-rvlE~T
The student responsps to the course and lab ~'ere ove1'"7helmingly positive. Since the final projects in many cases were at the level of capstone senior design projects~ the student,s were challenged to a..~similate and to put into practice all of the theory they had learned. The blend of theoretical lectures followed by hands-on labs is an excellent course structure from a motivational standpoint. On the one hand the students do not becolne bored with the theory as they imnlediately see its applications. ()n the other hand, the students gain practical experience in the lab that cannot be adequately addressed in leetures ~ frUIIl the problenl of sensor noise and the importance of noise filters to seemingly mundane bits of knowledge such as the need for flexible shaft
rection of Professor Shiv Kapoor. This support is gratefully ackno"vlcdged.
REFERENCES Alleyne, et. aL,(1996) A Col1egewide Laboratory-Based Program in Control Systenls Technology at The University of Illinois at lTrbana-Champaign, Proc. 35th IEEE CDC, Kobe~ Japan. Auslander, D. !vI. a.nd Tham~ C. H.,(I990), Real-TiTue Software for Control, Prentice-Hall, Englewood Cliffs, NJ. Auslander, DJv1. and Kempf, C.J., (1996)~ lVfechat1·onics: Mechanical Systems Interfacing, Prentice-Hall, l,lpper Saddle River, NJ. Bolton, \\7., (1995), M echatronics: Electroni c Control Systems in l\fechanical Engineering, Longluan Scientific & Technical Publishing~ Essex, England. FTaser~ JVL and Milne, .1., (1994)~ Electra-Mechanical Engineering: An Integrated i4ppr-oach, IEEE Press, Pist
catavlay, NJ. Horowitz., P. and Hill, ""l., (1989) The Art of Electronics, Cambridge University Press, CaInbridge~ England. Spong1 l\.1w\\Tw, (1996) Undergraduate Research in Robotics and Automation at the Universi ty of Illinois at l,-rbanaChampaign, 35th IEEE CDC, Kobe~ Japan. Hrt3bster's Ne,",~ "'orId Dictiona.rj:-, (1990), \Varner Books,
New York, NY.
couplers.
From an instructor~s viewpoint, Meehatronies is not an easy course to teach for the simple reason that it is extrerIlely broad and encompasses nearly all aspects of engineering. In addition, instructors face a constant struggle to maintain the laboratory at a state-of-the-art lp-vel, both because of the rapid pace of technology and also because of the increasing technological sophistication of students ,","ho demand t.he latest computer techno]ogy in the lab. For this reason, :tvlechatronics is best taught as an tearIl effort across departnlcntaI boundaries.
8. }\.CKNO\\TLEDGE:L\.1ENTS The ).Jlechatronics Laboratory \vould not be possible \vithout the encoura.gement and financial support of the Departments of General Engineering and Mechanical & Industrial Engineering at the ~ niversity of Il1inois~ the John Deere Corporation, and the College of Engineering rvlanufacturing E,ngineering Prograrn under the di-
6364
Copyright 1999 IFAC
ISBN: 0 08 043248 4
14th World Congress ofIFAC
Copyright © 1999 IFAC 14th Triennial World Congress, Beijing, P_R_ China
M-6a-Ol ~l
MECHATRONICS EDUCATION AT THE UNIVERSITY OF ILLINOIS Mark W. Spong and Tsu-Chin Tsao
lJniverS'ity of Illinois at Urbana-Champaign, Coordinated Science Laboratory, 1308 Ut~. Afain Str"cct, Urbana, lL~ 61801, [13...4 , [email protected]
Abstract. This paper describes the development of the College of Engineering ~VIecha tronics Labora.tory at the "Cniversity of Illinois and an associated course~ Introduction to A1echatronicB. The Jvlechatronics Laboratory is a shared facility in our College of E,ngineering~ part of the network of shared laboratories that we have developed to support courses in dynamics and control systems at the University of Illinois. The course a.nd laboratory are designed to give students practical experience in computer interfacing, real-time prograrnming, sensing, actuation, and control system design, as well as to serve as a springboa.rd to higher level concepts in dynamics and intelligent control~ such aH nonlinear and hybrid control, Inachine learning, fuzzy logic, neural networks, and discrete-event systems. Copyright © 1999 IFA(~
Keywords. mechatronics, control
education~ real-time
1. INTRODUCTION
rv1echatronics is often described as the synergistic integration of electrical engineering, COlllputer science, electronics~ rnechanical enginecring~ and control engineering (Fraser and Milne, 1994; Bolton, 1995). One may also think of IVlechatronics more concisely as '~putting intelligence onto physical systems." It is this second definition that drives our philosophy in the developInent of the IVlechatronics Lahoratory and the course, Introduction to Mechatronics. Definitions of '"intelligence" often include phrases like "the ability to learn" and Hthe ability to cope with new situations. (Webster's New \Vorld Dictionary, 1990). The advancements in microprocessor and sensor technology, occurring at an ever increasing pace, allow engineers to design electra-mechanical systClns that collect and process sensory data and respond in conlplex ways that can be said to mimic biological intelligence. l\1echatronics involves the design of such electro-mechanical systems.
Copyright 1999 IFAC
systems, embedded systems
Applications of Inechatronics engineering are myriad, including robotics and lllanufacturing systems, automotive and aerospace systems, everl household appliances and consumer electronics. The Mechatronic design engineer must be able to integrate diverse disciplines of engineering and must adapt to the rapidly changing technology that is continuously opening up new application areas. For example, the relatively new field of !\1E,!v[S (I\t1icro-Eleetro-!vlechanical Systems) offers tremendous potential for new applications but, at the same time, requires mechanical engineers to understand design issues at scales where quantum effects are important, and requires electricaJ engineers to understand new developments in materials science and so Oll.
This paper describes the development of a Mechatronics Laboratory and a course, Introduction to Mechatronics at the lTniversity of Illinois. The course and laboratory are designed to give students pract.ical experience in cornputer interfacing, real-time programrning, sensing~ actuation, and control system design, as well as to
6359
ISBN: 0 08 043248 4
MECHATRONICS EDUCATION AT THE UNIVERSITY OF ILLINO...
14th World Congress ofIFAC
serve as a springboard to higher level concepts in dy-
nalnics and intelligent control) such as nonlinear and hybrid control, machine learning, fuzzy logic neural net",,"orks, and discrete-event systerns. 1
2. THE LABORATOR).r NETWORK The rv1echatronics Laborat.ory is part of the network of shared laboratories that we have developed to support courses in dynamics and c.ontrol systems at the University of Illinois. In addition to the lVlechatronics Laboratory, our laboratory network consists of
The Mechatronics Laboratory contains eight funy equipped Vv·orkbenches to enable the design and realization of mechatronics projects. The laboratory also contains an active noise cancellation system and an active vibration control system, both produced by Digisonix, Inc.
4. THE COURSE DESCRIPTIC)N The course, Introduction to Mechatronics.. was offered during the Spring semester 1998 and cross-listed in the Departments of General Engineering (GE 393), and IVIechanical & Industrial Engineering (lE 393). The course is also listed as part of our ~lan\lfacture Engineering degree option program as MfgE 330, Interfacing .Alethods for Manufacturing Systems. Thirty students students eompleted the class in Spring, 1998.
(1) The College of E,ngineering Control Systems Laboratory, which we refer to as The Core Lab, (2) The Robotics and Automation Laboratory, (3) The Fluid Po~ver Laboratory, and (4) The Flight Control Syst.ems Laboratory. The Core Lab Vlas developed starting in 1994 to serve as a centralized facility replacing exisiting departmental laboratories and servicing all of the basic courses in feedback control systenls in the College of Engineering. By elevating our laboratory instruction froln the Departrnent level to the College level~ v.re are able to eliminate v..~aste and duplication~ hire a full-time lab manager, and keep the hard\vare and software up-to-date, while allowing the individual Departments to retain autonomy of their curricula. The four additional labs are referred to as Satellite Labs and are viewed as second-level laboratories to service courses in the various Departments that follow the introductory controls courses, such as courses in R,obotics, Mechatronics, Hydraulics~ and Flight ControL All of the labs are shared by the va.rious Departments in the College and are supervised by a committee of faculty whose interests lie in dynamics and control. Our shared laboratory concept is described more fully in Alleyne, et.al.~ (1996).
4.1 Topical Outline: The class consists of a single lecture section meeting twice per week together v;tith multiple laboratory sections~ each. meeting once per v.reek. The lectures are primarily devoted to the "higher level" issues such as system modeling and design, sensor and actuator dynamics~ and intelligent control theory, while the laboratory sections provide hands-on exposure to issues of computer interfacing) including interrupts, timing, real-time programming, and signal conditioning and include final design projects involving teams of students. The topical outline of the course i~ as follows:
L~-\B
3. THE 1\1ECHATRONICS
(3) $125,000 allocated from a $l~OOOlOOO grant by the General Motors Leadership Enterprise in "VIrtual Education Research (G~I-LE\'ER) PrograIIl (19972002).
The Mechatronics Laboratory \vas made possible by COIUbining resources {roln existing facilities new initiati ves ~ t
and generous external support. This includes" (I) Equipment from an existing course on Interfaeing ~1et.hods for Nlanufacturing Systems (i\1FG330j IE393) established in 1990 with support from General 1\110tors Computer Integrated Nlanufacturing: Education Program, (2) A $125~OOO gift from John Deere (1995-2000) to support ne\v initiatives in real-time control and mcchatronics education,
(1) Introduction (a) 'Vhat is l\1echatronics? (b) Mechatronics Design Philosophy (c) Examples of l\1echatronic Systems (2) Sensors (a) sensor terminology (b) static and dynarnic characteristics (c) position sensing (d) velocity and acceleration nH~al;urelnent (e) proximity sensing (f) strain gauges (g) force and pressure sensing (h) temperature sensing (i) filtering and signal eonditioning (3) Electric .Actuators (a) DC-motors (b) AC-motors
6360
Copyright 1999 IFAC
ISBN: 0 08 043248 4
MECHATRONICS EDUCATION AT THE UNIVERSITY OF ILLINO...
(c) Stepper rIlotorR (d) Brushless DC-motors Cc) motor control (4) Hydraulic and Pneuluatie Actuators (a) basics of hydraulic and pneumatic systems (b) control valves (r:) electro-hydraulic systems (cl) electra-pneumatic systems (5) Analog and Digital Electronics (a) transistor and diode circuits {b) operational amplifiers (c) inst rumentation anl plifiers (d) AID and D/.L~ converters (e) Power Rupplie~ (6) Computer Interfacing (a) Hardware and software organization Cb) Computer interfacing for analog and digital input/output devices (7) Real-time Systems (a) Soft and hard real-time systems (h) COluputer interrupts (c) Prioritized preemptive multi-tasking (cl) CPU timing diagram and loading factor (e) Progralnlnahle interval timers (f) System behavioral analysis: state transition di. agram and state chart (8) Systenl ~1odeling
assignrnents. The laboratory and project topics are as follows: Lab 1: Getting Started with C: An introduction to the computer and instrumentation, software environlnent~ and C prograrnming. Lab 2: Digital I/O: Cornpllter int.erfacing, LED and mechanical s\\Titches. Project 1: Simulation of a bank teller machine operator interface in C. Lab 3: .A.nalog I/O: AID and D/..~ interfacing, micromachined strain gage force and pressure sensors~ and signal conditioning circuits_ Lab 4: DC Motor Speed Control- Proportional Control Lab 5: Timer Interrupt~: cornputer interrupt generation and thermoelectric heat pump actuators Project 2: E·mulation of an automotive cruise control using a DC motor and I/O rnodule. Project 2 requires rnodification and integration of Labs 2-4. Lah 6: DC motor PI control using a timer interrupt. Incremental encoders and encoder interfaces. Lab 7: l\1ultiple soft~rare tinlers and external interrupts. piezoelectric switch, optical switch, and debouncing circuits for triggering external interrupts. . Lab 8: Stepper motor control: stepper motor operatIng principles, motor wiring~ pulse/frequeney generation software, and testing of maximum start-up torque and slewing speed. Project 3: Real-time monitoring and control of a machine tool spindle, emulated on the DC motor and I/O module. Project 3 requires modification and integration of Labs 5-7. Lab 9: Binarv state actuators and pO~'er control: clectromagneti~solenoids, shape memory alloy actuators, and power s,\\'itching lllodules. The software used for timer interrupt and lllultiple software timer is adopted from Auslander and Tham (1990).
(a) li near a.nd non] inear systems (b) cq uilibria and stability (c ) lincarization (9) Classical and ~1odern Control (a) transfer functions and block diagrauls (b) state space systems and realizations (c) Controllability and 0 bservabili ty (d) Digital Control (e) Pole Assignment and Optima.] Control (f) Observers (g) Duality and the Separation Principal (10) Intelligent Control Ca) Fuzzy Logic and Fuzzy Control
6. FIN.A.L PROJECTS
(b) Neural ~ctworks (c) Dis~rete Event SystelDS
Students form teams of t\vo or three persons and create their ov.rn final projects. The final project guidelines require that. the soft.ware nlllst have a real-time comput~ng component and the hard\vare must explore somethIng not covered in the regular labs. For the Spring 98 class, the projects chosen by the students were:
(cl) Logic-Based S\vitching Control
5.
L.tI\B()RATOR:Y~
INST'RUC'TION
The laboratorv instruction consists of nine laboratories and three regular projects during the first 11 weeks of the semester, and a final project during the last 5 weeks of the seInester. The three regular projects are designed such that students must modify and integrate softwarejhard\vare components covered in the previous weekly laboratory nlaterials to accomplish the project
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(1) (2) (3) (4) (5) (6) (7)
.Lo\ 2-D light tracking system. A ski-jump ball bearing catcher. .A. programmable length paper cutter. An electronic cam motion system. .LA-. smart traffic c:.ontroller. An automatic guitar tuner. A robotic material sorter based on height.
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(8) A ball and beam balancing system. (9) .A. noise and vibration cancellation DSP module using the Digisonix hard\varc.
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C~-program
6.1 Selected Project Abstr'act.s BeloVv~ are reproduced a subset of the projec.t. abstracts fronl the student final reports together "\vith photos of SOlnc of the projects. For the complet~ liRt of projects and their abstracts, the reader may consult the, class ,,""ebsite at http;l/robotO.ge.uiuc.edu/~spong/mechatronics~
• Project 1: Ball Bearing Catcher Fig. 2. Electronic Cam Profile Generator paper on Vv"hich the ca:rn 1S being drawIl~ The different angular positions of the paper ca.n be aehieved using a stepper lnotor. l)he different radial positions of the peneil ean be achieved by at.taching the pencil to a linear motor. Thus a suitable soft~ ware control has to be developed to control a linear motor, and hardware caonfiguration is to be set up for canl profile generation. The HysteIll has to be flexible for different types of cam profile generation. This includes variations in rise, fall 7 dwell angle, as well as rise and fall profileH, i.e. linea.r, parabolic, etc. R,obust implementation is required so as to bH able to generate cam profile at high speeds (60 rpm) . • Project 3: 'I'he Dalancing.~et
Fig. 1. Ball Bearing (jatcher ~ ()nly the ramp is sho\vn here. Not. sho\vn is the cart. vvhieh IllOVPS along the floor to catch the ball rolling off the ramp. Ab8t'l"(lCl: l.'his project involves the design of a ramp and a ball bearing catcher. Jot\. steel ball rolls do~~n a ski-jump shaped ra-nlp and thp tinH~ it takes for the ball to pass bet,veen two switches on thf: dov,rn\vard ~dope is llleasured. rfhe ball flies off the end of the ramp and a cart at the end is llloved to a position to catch it calculated in real tirrle. T\vo optical sv.ritches are used as hardware interrupts and are switched \vhen the ball passes by thelTI. l'he cart is mounted on a belt which iH controlled by a stepper InotOl". 'I'his project involves the use of hardvlare interrupts, digital i/o~ analog output~ and
open-loop control. • Project 2: Electronic Canl Profile Generator using Linear Actuator & L\/D'l' .Abstract: The nlain objective of this project is to develop an electronic cam profile generator..A. ca.n) can be generated by moving a penf:il raJiially to different positions at different angular positions of the
Copyright 1999 IFAC
,Fig. 3. Ball and Bealu Systerll
Abstract: l he 109S American Cont.rols Confernee CA.CC) presented the following design project as student competit.ion: balance a ball on abeam by changing the angle of the bearn under the ball. The 1
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design project ~~as entirely theoretical. Each student received a SIl\.1UI.lINK rTlodel of the phyHical system, and the. controller design and testing \vas based entirel~'( on this oroclel. Because 'vc already had the ban, motor, a.nd sensors available, we decided to physically implement this design. Our goal in designing and building this system was to pro~ vide a t(-~stbed for future students to develop their o\vn controllers or sensors. • Project 4: Real-Time Control Sinlulation of an r\ntiLock Braking Systenl (ABS)
Fig. 5. 2-D Light 'Tracking System
axeH. The ohjective here \vas to achieve tracking in real time. 'I'hus, systern response tilnp, for sensing the light and subsequent control of the motors to track the light are of vital inlportancc. Four light sensors v.rere used in this project and they ~~ere oriented perpendicualr to each other in such a way that the relative magnitude of any two sensors deterlnineH the direction in which a particular OlD--tor needs to be moved to track the light HourCf~. A setup like this could find applicatinos in solar panels where the orientation of the panels needs to be ehanged during t.he course of the day to ensure that light al\vays falls .normal t.o the panels~ thereby ensuring the rnaximum energy is generated by the panels. Fronl L,an1bert~s cosine law~ v\"e kno\v that thp., intenHity of light falling on a surface is proportional to the cosine of the angle bet,~.reen the Ilorrnal
Fig. 4 ..A.BS sirnulatoI'. The t~r() Inotors Hlust be synchronized in such a way that the basketball rolls about a single axis \\rithout "\vobbling.
This project entails the shnulation of an antilock braking systenl (A•.BS) cllrrently available on a grov,ring nunlber of passenger cars and commercial vehicles. 'I'he ABS will ensure that during severe braking the wheel velociti8g are at all tilnes p,quiva.lent in order to prevent the ocurence of ","'heel lockup~ skidding 1 or s\vaying. In this project., t"vo nlOt.on~ are utilized for th8 indiyidual control of a set of wheels. Eaeh wheel is equipped with a proportional plus integral (PI) controller as is the velocity regulator ~ intended to equilibrate the wheel velocities upon initialization of a situaitioIl resembling lock-up. The performance of the A.BS systerrl IIlay be adjudged by either the real-tinle visualization of a ball-rotating apparatus, or throu~h graphical d(-~piction subsequent to data acquisition. Both opt.ical encoders and t.achometers are Inounted to the two motors to facilitate feedbaek control. • Project 5: Autonlated Light rrracking Systenl Ab"dr·act: The ainl of this project "vas to develop a light, tracking system by t,vo axis Inotor eontrol. ~t\ny light source present in a hernispher~ can be tracked by 180 degree rnotion of t\VO perpendicular
to the plane and the light source. Thus~ irnproper alignrnent of t.he panels could lead to drastic red llCtion in the energy that is captured by the panels. One could also think of other applications for this simple t\VO axis control in which the signal source is SOlllething other than light, e.g;. tculpcrature or Illagnetic field as in radars or other navigat.ional equipment where one needs to trak a given energy source by continuously ll1onitoring the sig;nal and orienting an axis \vith respect to the current position of the energy source. • Project 6: Simulation of Smart Traffic Lights .4 bstract: T'he goal of this project is to simulate "~rnart" traffic lights. ,~ SInarf~ lights are traffic .s-ignals that are able to sense the f}(HV of traffic, and thus can cont.rol the length of their varjous traffic commands. In this simula.tion, steel balls rolling down t~TO intersecting tracks simulate various traffie. eonditions on lnterspcting road"vays. T\vo pic~~o-
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electric sensors are used to sense the approach of the traffic (balls), and et C prograrrl controls the traffic si?;oals. The project is also augmented ~~ith additional features, such as an emergency vehicle s'\Jrritch. The prograIn is conlpatible with the IB!vIPC hardware platform. The team successfully developed and implemented a system for the simulation of thfl ~'Slllart" lights. The traffic lights are triggered by the balls rolling throught the piezo-eleetric switches. A stepper motor is also used to st.op the balls in the direction of the red light. Finally, there are LED lights that indicate \\I'hich traffic light is red.
7.
.L~SSESS-rvlE~T
The student responsps to the course and lab ~'ere ove1'"7helmingly positive. Since the final projects in many cases were at the level of capstone senior design projects~ the student,s were challenged to a..~similate and to put into practice all of the theory they had learned. The blend of theoretical lectures followed by hands-on labs is an excellent course structure from a motivational standpoint. On the one hand the students do not becolne bored with the theory as they imnlediately see its applications. ()n the other hand, the students gain practical experience in the lab that cannot be adequately addressed in leetures ~ frUIIl the problenl of sensor noise and the importance of noise filters to seemingly mundane bits of knowledge such as the need for flexible shaft
rection of Professor Shiv Kapoor. This support is gratefully ackno"vlcdged.
REFERENCES Alleyne, et. aL,(1996) A Col1egewide Laboratory-Based Program in Control Systenls Technology at The University of Illinois at lTrbana-Champaign, Proc. 35th IEEE CDC, Kobe~ Japan. Auslander, D. !vI. a.nd Tham~ C. H.,(I990), Real-TiTue Software for Control, Prentice-Hall, Englewood Cliffs, NJ. Auslander, DJv1. and Kempf, C.J., (1996)~ lVfechat1·onics: Mechanical Systems Interfacing, Prentice-Hall, l,lpper Saddle River, NJ. Bolton, \\7., (1995), M echatronics: Electroni c Control Systems in l\fechanical Engineering, Longluan Scientific & Technical Publishing~ Essex, England. FTaser~ JVL and Milne, .1., (1994)~ Electra-Mechanical Engineering: An Integrated i4ppr-oach, IEEE Press, Pist
catavlay, NJ. Horowitz., P. and Hill, ""l., (1989) The Art of Electronics, Cambridge University Press, CaInbridge~ England. Spong1 l\.1w\\Tw, (1996) Undergraduate Research in Robotics and Automation at the Universi ty of Illinois at l,-rbanaChampaign, 35th IEEE CDC, Kobe~ Japan. Hrt3bster's Ne,",~ "'orId Dictiona.rj:-, (1990), \Varner Books,
New York, NY.
couplers.
From an instructor~s viewpoint, Meehatronies is not an easy course to teach for the simple reason that it is extrerIlely broad and encompasses nearly all aspects of engineering. In addition, instructors face a constant struggle to maintain the laboratory at a state-of-the-art lp-vel, both because of the rapid pace of technology and also because of the increasing technological sophistication of students ,","ho demand t.he latest computer techno]ogy in the lab. For this reason, :tvlechatronics is best taught as an tearIl effort across departnlcntaI boundaries.
8. }\.CKNO\\TLEDGE:L\.1ENTS The ).Jlechatronics Laboratory \vould not be possible \vithout the encoura.gement and financial support of the Departments of General Engineering and Mechanical & Industrial Engineering at the ~ niversity of Il1inois~ the John Deere Corporation, and the College of Engineering rvlanufacturing E,ngineering Prograrn under the di-
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