TECHNOLOGY EDUCATION THROUGH MECHATRONICS Ahmad Smaili Mechanical and Mechatronics Engineering Department Hariri Canadian University Meshref, Lebanon Email:
[email protected]
1. Motivation and Approach The impact of technology on contemporary life is startling. The goal for a society is to use technology to advance its economic growth while reducing its adverse effects on positive cultural inclinations. A key to achieving this goal is a wholesome education of all involved in the technology chain, including the policy maker, the user, and workforce. All sectors at all levels in the society must cooperate synergistically to harness the positive forces of technology to maximize its benefits to the society while minimizing its adverse effects. A key group in the chain is the technical workforce, well educated, can maximize the value added to natural resources through the use of technology. A properly designed educational enterprise is the platform through which seeds for innovative and creative uses of technology are planted. This requires providing technicians and engineers with the skills to integrate a number of technologies including electronics, mechanical devices, microprocessor, real-time control, communications, materials, and human-computer interaction. Mechatronics provides the platform in which effective integration is accomplished. Although the current paper focuses on mechatronics engineering education, a mechatronics curriculum may be designed to meet the needs at any desired level, from a two year technical training to a fouryear college degree and beyond. The ingredients are practically the same but the intensity of the topics covered varies with the outcome level of interest. A strong component of the model is collaborative, project-based, learning-by-doing experience in which students are trained to use advanced technologies and to realize devices for a social need
using various modern tools. The implementation strategy involves minimal lecturing, seamless lab/lecture interface, just-in-time learning, and students’ empowerment to work on communitybased projects of their choosing. An example of a typical students’ project is presented and course assessment is briefly discussed.
2. Introduction The breathtaking speed at which technology is advancing is influencing to a large extent the future and spirit of the world in which we live. “Properly harnessed and liberally distributed, technology has the power to erase not just geographical borders but also human ones [1].” Economic competitiveness requires the commercialization of knowledge and technology to maximize the value added to the natural resources of a given context. To a large extent, the security and survival of a nation is becoming increasingly dependent on technology to maintain law and order which are necessary conditions to economic security. Technology can only be mastered through education. A technical workforce that masters technology as it develops and quickly integrates it into products well ahead of the competition must not be a choice, but a must for any society that aspire to make a difference. Mechatronics, being an interdisciplinary field, plays a key role in educating the “maestros of technology” [2, 3]. The importance of mechatronics is manifested by the myriad of smart products all around us, from the little robotic toy that could climb walls to all the stuff that constitute a modern “electronic vehicle”: Engine controls, anti-lock
braking systems, active suspension systems, collision avoidance, drive by wire, electronic muffler, and all the functionality of a PC residing beneath the dashboard. All types of machines and gadgets in any power plant, airplane, hospital, TV station, and production facility are examples of mechatronics products [4-7]. While many social, economic, and political forces are ultimately responsible to produce the necessary “technology smart” workforce, education plays a vital role. The contribution of curriculum offering in institutions represents a link in a synergy chain. If the chain is as strong as its weakest link, education is the only way to strengthen a weak chain. The quality of a contemporary system or product relies on the harmonious interaction between mechanical systems, sensors, actuators, and computers. Thus, to use technology effectively, technicians and engineers must be able to transcend beyond barriers that separated various disciplines in the past. Proper use or the realization of a mechatronics system requires knowledge and expertise in mechanical components, sensors and actuators, electronics, control, and the use of computer software and hardware. Figure 1 shows a simple temperature control of fluid in a tank that highlights the integration of the various technologies. This article presents a model for educating technicians and engineers in mechatronics. The various elements of the model can be designed in alignment with the educational objectives and learning outcomes.
3. Mechatronics Education Goals and Objectives Traditionally, technicians and engineers are trained to have a set of skills that focus on one aspect of a system. For example, a mechanic is trained to apply energy and motion principles, but receive little or no training on how to interface a mechanically functioning device with its surrounding environment using appropriate sensors, actuators and controllers. On the other hand, an electrician acquires skills in electrical and electronics systems but little or no training on how
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Supplies 500 mA @ 50 V.
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Figure 1: A simple temperature control of a fluid tank highlighting the integrative nature of mechatronics. mechanical systems work. This form of training is no longer sustainable. Like the human body, any meaningful system can only function if all its susbsystems function in a perfect harmony. Therefore, any educational process must provide students with the proper platform to achieve the following goals: • Interact with the community to work on topics and projects relevant to its needs. • Educate a workforce that posses the skills to satisfy societal and industry needs and the ability to effectively function in a technology based workplace. • Integrate fundamental knowledge in ways that lead to efficient solutions to pressing current and future technical problems, • Appreciate and work in teams, • Focus on creative learning techniques, develop and evaluate alternative solutions to real-world problems, • Obtain a holistic understanding of systems, • Learn the basic skills of leadership by seeking solutions to community based problems. Based on these goals, specific objectives are derived for the student to learn how to: • Integrate knowledge from various disciplines to achieve a successful solution to complex technical problems. • Break up a complex problem into manageable components, how to efficiently assign roles within a team, and how to inter-depend on each
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other to achieve the desired goals. Obtain and apply basic technical skills that tradition has it as outside their major discipline to meet the needs of specific projects. Generate a number of diverse solutions to openended problem that exhibit creative thinking, beyond classroom examples. Plan and implement necessary steps involved in development cycle of a specific product from the statement of need up to a functional product. Effectively organize the processes of the group and play different roles within the team, especially a leadership role.
Infrastructure in Support of Objectives The mechtaronics educational model shown in Figure 2 is proposed to achieving the aforementioned goals and objectives. The model includes the various technologies involved in every technology-based industry including water resources management and treatment, desalination plants, oil refineries, health care facilities, broadcast media, forensic science, communications and networking, to name a few. In addition to basic sciences and humanities topics, a generic mechatronics curriculum may include the following topics: • Engineering for the community • Electric Circuits • Computer programming • Mechanics of Machines • Dynamic Systems Analysis • Pneumatics and Hydraulics Systems • Electronics • Machine Elements
Microcontrollers: Programming and Interface Manufacturing: CAD/CAM, CNC, Robotics, Manuf. Processes
Product Design and Development
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Dynamic Systems Analysis: Modeling Signal Analysis
Instrumentation: Sensors Signal Conditioning Data Acquisition
Controls and Automation: Design of controllers Hardware+Software
Figure 2: Generic components of a mechatronics curriculum.
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Instrumentation and Measurements Microcontroller technology Creativity, Innovation, and technology Sensors and Actuators Controls and Automation Programmable Logic Controllers Product design and development Community based project
The intensity of topics and experiences covered in the curriculum can be designed to suit the level of interest. A major component of the model is the laboratory hands-on experience that is essential to technology-based learning to put theory to practice: “I hear I forget, … I see I remember, ….I do I understand”. The lab experience provides the environment where students’ technical and nontechnical skills can be nurtured through carefully prepared experiments and projects. While several laboratories may be needed, depending on the educational outcomes, the focus hereafter will be on one main laboratory that includes the necessary tools for many required skills including instrumentation, microcontroller-based systems, and control. Proposed Mechatronics Laboratory This section briefly highlights the components of the mechatronics and creative learning laboratory (MCLL) that is being developed at HCA. The laboratory will include several stations each contains the following items: National Instruments Educational Laboratory Virtual Instrumentation Suite (NI-ELVIS) with LabVIEW software and high speed data acquisition board for instrumentation and control applications; MCUSLK kit to develop HC12 microcontroller-based applications with a PCI Style Card-Edge connector designed for use with National Instrument's NI-ELVIS platform; Programmable logic controllers (PLCs), Actuator and sensor kits; Power supplies, oscilloscope, function generator, multi meter, and internet-connected PC equipped with. The laboratory should also includes a bookshelf of manufacturer’s handbooks and manuals, reference books, and related magazines, and cabinets of various analog and digital components, stepper motors, dc motors, servos,
motor driver ICs, transistors, IR emitter/detectors, solenoids, cables, sensors and accessories. The laboratory may also be fitted with table top CNC lathes and mills with related CAD/CAM software to provide students with skills in using CNC technologies in manufacturing. Teaching/learning Strategy The entire learning experience should be teamoriented. It is well known that, properly applied teamwork efforts breads healthy competition, stimulates creativity, and culminates in ever more meaningful outcomes. Consequently, students should be grouped in teams of 3 from day one into the course and introduced to the importance of teamwork, its mechanics, and how it is applied. Students will then apply these skills throughout their studies. To highlight the teaching learning strategy, the experience in the MCLL is summarized herein. The purpose is not to suggest a piecemeal approach for every course, but to shed light on the author approach to providing a creative learning environment. Each team is assigned a laboratory station and a project work area to build simple experiments to practice lecture content and to develop assigned projects. The strategy in realizing the desired course/lab educational outcomes and objectives is summarized in the following sections. Lecture/laboratory environment: The approach taken deviates from the conventional separation between lecture and laboratory components. In the new approach, lectures and lab experience are completely integrated. To provide students with the incentive and opportunity to shoulder more responsibility for their learning, lecturing in the course/lab period is kept to a minimum. In a typical class/lab session, the instructor introduces major features of a given topic for a short portion of the class period. The instructor then plays a facilitator’s role for the rest of the period. As students work on their projects questions do always come up that requires just-in-time learning, managed in a manner that guides students to obtain answers on their own. Additionally, students are free to roam around the lab, ask each other questions and learn from each other’s experience. In many class periods, the instructor serves as a source of information and
overseas activities to ensure students’ teams engage in effective cooperative, learning-by-doing effort to practice what they learned in the lecture. Collaborative Project-based learning: The course/lab focuses on open-ended projects instead on a sequence of structured laboratory experiments. Students in a given semester are required to complete four or five meaningful projects, depending on the complexity of the projects. In each project, students are required to develop an application-specific mechatronic device. While the instructor suggests the projects’ statements, teams are given the opportunity to provide a project statement of their own. If the student-generated idea for a project is comparable in scope with that suggested by the instructor, then the team is allowed to pursue that idea. The aim of student-generated ideas is to involve students in deciding what they want to learn and get them to work on something they may further pursue after graduation, thereby enhancing their entrepreneurial venture prospects. It is also designed to reflect the role of technicians and engineers as problem definers in addition to being problem solvers. Teams who choose to work on an instructor-suggested project are also encouraged to modify the project statement and add to it features they deem important and relevant to their current or future needs. Typical projects include: a home security system, a smart elevator, a mobile robot, a conveyor belt system, plastic bags recycling machine, traffic regulation system, and so on. At the end of each project, each team is required to make a presentation on their device in the presence of other teams’ members and to provide a formal report.
4. Case Study of a Team Project: Smart Elevator An example of an instructor-assigned project, further modified by students, was to design and build a three-story small-scale elevator that operates either under the command of human voice or by normal way of pressing desired floor keys. The elevator (Neovator) is meant to be user-friendly for the disabled. Figure 3 shows the main components of the elevator. The elevator is controlled via a PC to which a 68HC11 micrcontroller is interfaced. The
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Figure 3: Schematic of the elevator system project integrates the use of many programming languages, C++, Visual Basic, and assembly with the voice recognition software, Voice Xpress. While class lectures focused on assembly and the 68HC11, students used other language skills learned in a course on programming, and languages they learned on their own to complete the system. No formal lecturing on interfacing the 68HC11 with the PC was given. Students learned and implemented this skill on their own. Self-learning and research are essential attributes of engineers as EC2000 criterion 3 states. The project also provided students with the opportunity to use the programmable timer, interrupts, A/D converter, and I/O ports facilities on the 68HC11, displays, and interface electronics (analog and digital). The temperature - measured by a thermistor – is displayed on a screen via voice command. Mechanical design skills acquired in earlier courses were also utilized to design and implement elevator guides for the car, bearings, hoisting, gear-drive, housing, etc.
The PC is the master brain that controls the operation of the Neovator. Once a voice command is received, the voice recognition software, Voice Xpress, runs two executable files. The first “.exe” file, coded in C++, generates the appropriate signal to the PC serial port. For example, if the PC receives the command “GOTO FLOOR 1”, it writes “&h2” to address &h379, which sets the 10th pin of the PC parallel port to 1. This in turn commands the 68HC11 micro controller to send the elevator to Floor 1. Similarly, a command “Go To Floor 2” or “Go to floor 3” would cause the PC to write “&h4” and “&h8” to address &h379 and set the 11th and 12th pins on the parallel port, sending the elevator to floors 2 and 3, respectively (&h For hexadecimal in C++). The second “.exe” file, coded in Visual Basic, displays the floor number on the PC screen. Once the elevator reaches a floor, the door opens automatically allowing the passenger to go in or out. The floor-selection keys are interfaced to pins PC0-PC2 of the 68HC11 port C. When the elevator passes a given floor, it trips a corresponding switch so that when the desired floor switch is closed, the software knows that the car has reached the destination floor. The floor switches are interfaced to port C pins PC3-PC5. The ON/OFF and direction of motion of the drive motor are supplied via pins PC6 and PC7 of port C. The code operates as follows. The CPU scans Port C until a high at a pin to which a floor key is interfaced is detected. It compares the input to a ram variable that keeps the current location of the elevator. The result of this comparison is used to define the direction of elevator travel, either up or down. The elevator starts to move in the proper direction until the destination floor-switch is closed, signaling the arrival of the elevator to the desired floor. The thermistor used as a temperature sensor is interface to the A/D converter via pin PE1 of port E of the 68HC11. The thermistor signal is filtered, amplified, and then subtracted from an offset so as the output falls within the full scale of the A/D converter, which is 0 to 5 V. The A/D converter is scanned continuously and the result is written to port B where it is retrieved by the PC and displayed on a terminal screen whenever the Voice Xpress recognizes “READ TEMPERATURE” command.
5. Summary This article proposed a model for mechatronics education for technicians and engineers. Technology based work environment in which barriers between various engineering disciplines continue to shrink into oblivion, and integration of mechanical systems with sensors, actuators, computer interface and control is becoming increasingly important. The proposed model integrates key technologies essential to competitiveness and to help in using technology solve society problems. A learning/teaching strategy is proposed in which the lab experience to enhance students’ skills in using modern tools is vital. Acknowledgment - The author acknowledges Mechanical Engineering students Firas Zeineddine and Barbar Akle for completing the Neovator project as part of a mechatronics course at the American University of Beirut.
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