E-LEARNING OF FLUID POWER: PNEUMATICS€¦ · vocational trainees (National Trade Certificate...

Journal of The Institution of Engineers, Singapore Vol. 44 Issue 5 2004

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E-LEARNING OF FLUID POWER: PNEUMATICS

C.L. Kho, Patrick S.K. Chua and F.L. Tan1

ABSTRACT Advancement in information technology has led to the commencement of e-Learning. It has totally changed the concept of learning that has been well adopted for a long time. ‘Any time, any place’ is becoming a more convenient learning method in the current dynamic world. This paper describes the development of a multimedia teaching package in pneumatic circuit design. It discusses the concept of e-learning, presents the pneumatic contents covered in the package and also the development processes. Various types of emergency circuit design techniques have been incorporated into the package to suit different needs of users. Macromedia Flash MX has been used as the main development platform for this interactive teaching package. The courseware has been fully tested. It serves as a supplementary teaching package for the instructor or a self-learning package for learners who are interested in pneumatic circuit design.

INTRODUCTION One revolutionary impact of the information technology in today’s knowledge-driven economy is that it changes the way people learn, communicate, work and live. With the presence of the Internet, learning will no longer be bounded by the old traditional form that is merely dependent on classroom training or based on books alone. In fact, nowadays people can easily obtain knowledge or information by just a simple click of the mouse in the comfort of their home. E-Learning has become a new trend whereby each individual is able to set their own learning pace anytime anywhere. It can be a very rich learning experience that can even surpass the level of training experienced in a crowded classroom. E-Learning can be generally classified into four categories, from the very basic to the very advanced, which are Knowledge Database, Online Support, Asynchronous training, and Synchronous training. Knowledge Database is the most basic form of e-learning. It may be found at software sites offering indexed explanations and guidance for software questions, along with step-by-step instructions for performing specific tasks. These are usually moderately interactive, meaning that the users can either type in a key word or phrase to search the database, or make a selection from an alphabetical list. Online Support is also a form of e-learning and functions in a similar manner to Knowledge Databases type of learning. Online support comes in the form of forum, chat rooms, online bulletin boards, e-mails, or live instant-messaging support. It is slightly more interactive than knowledge databases and it offers the opportunity for more specific questions and answers, as well as more immediate answers.

1 School of Mechanical and Production Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798


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Asynchronous training is a more traditional type of e-learning. It involves self-paced learning through CDROM-based, Network-based, Intranet-based or Internet-based. It may include access to instructors through online bulletin boards, online discussion groups, e-mail or it may be totally self-contained with links to reference materials in place of a live instructor. Lastly, synchronous training is another type of e-learning which is done in real-time with a live instructor facilitating the training. Everyone logs in at a set time and communicates directly with the instructor and with each other. Users can raise their ‘cyber hand’ and even view the cyber whiteboard. It lasts for a set amount of time -- from a single session to several weeks, months or even years. This type of training usually takes place via Internet Web sites, audio- or video-conferencing, Internet telephony or even two-way live broadcasts to students in a classroom. Anticipating the potential growth in this field, and yet there is hardly any software in the current market that deals with pneumatics teaching with rich multimedia content, the authors aim to develop a multimedia teaching package in pneumatics to enable students to learn the subject at their own pace, anywhere, anytime. This courseware will be distributed in two versions namely: CD-ROM and Internet versions. This will make the teaching package more flexible and the users can choose whichever version they prefer based on their need and comfort. The focus of this paper is on emergency circuit design although the courseware developed also covers other topics in pneumatic circuit design and pneumatics components/system. Multimedia teaching package in fluid power hardly exists today. The only one reported in the literature is by Tieh and Lee (2002) whose work is aimed at vocational trainees (National Trade Certificate NTC-3) in basic pneumatics and the work was only at the beginning stage. The work reported in this paper is part of a continuing effort to develop a complete multimedia teaching package in pneumatics especially on the design of pneumatic circuits (Tok 2001, Tjahjadi 2002 and Kho 2003).

COURSEWARE DEVELOPMENT By considering compatibility as the major concern in selecting the development platform, Macromedia Flash MX has been selected by the authors as the major development software in constructing the courseware. Macromedia Flash MX is a powerful development tool, with the ability to pull in and deliver a wide variety of web media and data sources. It is suitable for creating multimedia teaching package, animated logos, web site navigation controls, long-form animations, entire Flash websites, or web applications (Mohler, 2002). Figure 1 shows the working environment of Macromedia Flash MX.


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Figure 1: Flash working environments

Creation of animation using Macromedia Flash MX Frequently, animation is widely used in multimedia teaching package. Interesting and sophisticated animation is important to illustrate the content of the courseware and provide better information. One of the reasons for choosing Macromedia Flash MX in developing the courseware is due to its ability to create complex animation. There are basically two methods for creating an animation sequence in Macromedia Flash MX namely, frame-by-frame animation and tweened animation (Tyler and Rebholz, 2001). In frame-by-frame animation, image in every frame has to be created by the courseware developer, whereas in tweened animation, only starting and ending frames need to be created. Therefore, time and effort can be greatly reduced by using tweened animation.

a) Frame-by-frame animation Frame-by-frame animation is one of the traditional methods to create an animation. It is a tedious and time-consuming method in which the contents of the stage are changed in every frame. Besides, frame-by-frame animation increases the file size more rapidly than tweened animation. In spite of this, it is best suited for creating complex animation in which the image changes in every frame instead of simply moving across the stage. Due to the limitation of drawing 3-D image in Macromedia


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Flash MX, the authors decided to use frame-by-frame method in creating some of the animations in this multimedia-teaching package. Pro Engineer 2000i is used in conjunction with Macromedia Flash MX to create the animations. This is because Pro Engineer 2000i is the best tool in drawing 3-D object and has the capability of exporting files into image files such as JPEG file or TIFF file. In order to create a frame-by-frame animation, each frame is defined as a keyframe and different image can be created for each frame.

The following are the steps involved in creating an animation using frame-by-frame method. First of all, the required image files need to be drawn and exported as using Pro Engineer 2000i. In order to create a sequential of motion, dimension and position of individual part in the drawing file need to be changed frequently and the file exported as an image file. Pictures need to be modified and refined before they can be used in Macromedia Flash MX. Graphic softwares such as iGRAFx image, Paint, Photoshop are used to edit the pictures. Lastly, pictures are imported directly through Macromedia Flash MX into each keyframe. Editing is required until the desired motion is achieved. Figure 2 shows an example of a milling operation which is animated using frame-by-frame method.

Figure 2: Creation of animation using frame-by-frame method


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b) Tweened animation Tweened animation is an effective way to create movement and changes over time while minimizing file size. It is a more convenient type of method to create motion. The file size can be greatly reduced compared to the frame-by-frame method. Most of the animations in the courseware are constructed by using this method. Macromedia flash MX is able to create two types of tweened animation namely motion tweening and shape tweening.

In motion tweening, properties such as position, size, and rotation for an instance, group, or text block at one point in time have to be defined by the courseware developer before an animation can be created. Subsequently, by changing those properties at another point in time a simple motion can be created. Figure 3 shows the creation of a simple motion using motion tweening. On the other hand, instead of changing the postion or size, shape tweening changes the shape of an instance at one point in time to another point in time. Macromedia Flash MX is capable of interpolating the values or shapes for the frames in between the keyframes and hence creating the animation. Creation of animation using shape tweening is shown in Figure 4.

Figure 3: Picture showing creation of a simple motion using motion tweening


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Figure 4: Picture showing creation of a simple motion using shape tweening

Creation of animation using Ulead Cool 3D Besides using Macromedia Flash MX as a primary tool in developing the animation, the software Ulead Cool 3D was also used as a supplementary tool. Figure 5 shows the working environment of Ulead Cool 3D. It is a powerful 3D titling software that allows the courseware developer to create high-impact, animated 3D titles and graphics for presentations, videos and web. Ulead Cool 3D provides stunning special effects plug-ins, 3D geometric shapes, and powerful vector object editing capabilities. Ulead Cool 3D also provides a separate 3D vector editor, the EnVector module, which enables the courseware developer to create and export animated 3D vector graphics as Macromedia Flash (*.swf) files.

Figure 5: Working environment of Ulead Cool 3D


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Creation of Video Clips One of the improvements in this multimedia-teaching package is the additional of video clips. There are a total of 13 video clips added into the package. With the use of video clips, the content of the courseware can be clearly illustrated and the teaching package will be more user-friendly. Users will be able to experience how the circuits are being connected with real pneumatic equipments and this approach is hardly found in any other teaching package nowadays. A high resolution digital camera with video capability has been used for the video taking. The video clips are then imported into Macromedia Flash MX and published as a Flash movie (SWF file). Figure 6 shows a video clip of a two-handed safety starting circuit. The quality of the video can be adjusted to control the amount of compression applied to the video clip. A lower quality setting produces a smaller file size but it may reduce image integrity.

Figure 6: Video clip of simple two-hand starting circuit

Creation of Quiz using Macromedia Flash MX Another new feature in Macromedia Flash MX is its ability to include learning interactions into the package (Heins and Himes, 2002). The courseware developer can choose different templates from the list to create his own quiz. The quiz templates are designed for scenarios in which interaction-based quizzes are required and tracking is necessary. The quiz templates are fully functional. After a document has been created using the flash template, an immediate test can be carried out by the developer to examine the actions.


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There are six learning interaction types stored in movie clips in the library, namely: Drag and Drop, Fill in the blank, Hot Objects, Hot Spot, Multiple Choice and True or False. These movie clips are simply containers for the collection of elements that make up each interaction. For this learning package, Multiple Choice format is chosen for the quizzes. The very first step in creating a quiz is to select a quiz template in the Category Items column. This is followed by the setting of quiz parameters. These parameters control how the entire quiz is presented to users—for example, whether the questions are presented in a random or sequential order, LMS tracking information, and whether the Results page is displayed. Each question in the quiz is considered an interaction. Frames and keyframes can be added or removed as long as the interactions remain sequential and the first and last frames are reserved for the Welcome page and Results page. Modifications of the Welcome page and Result page can be made by selecting the first and the last frame in the Interactions layer (Figure 7). However, interaction cannot be incorporated in these frames. Contents in the frames between the first and the last frame can be changed freely. It is important to leave the supplied dynamic text field names intact, or the results will not appear. If the Results Page quiz parameter was turned off for the quiz, this frame will never be called, but it is still reserved. The quiz templates are incorporated with six types of learning interaction, which are stored in the movie clips in the library. These movie clips are simply containers for the collection of elements that make up each interaction. To freely edit the contents as desired, movie clips on the stage must first be separated. The user needs to split the entire learning interaction into individual objects. However, split command can only be executed once to the interaction.

Figure 7: Interaction layer


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COURSEWARE CONTENT There are thirteen topics in the courseware namely, Introduction to Pneumatics, Fundamental Pneumatic Principles, Sizing of Pneumatics Components, Pressure Loss Calculation, Basic Pneumatics, Types of Pneumatic Control, Circuit Design, Emergency Circuit Design, Pneumatics Symbol Library, Quizzes, Nomenclature, Help and Assessments. The main focus of this paper is on Emergency Circuit Design. The emergency circuits developed for this courseware are based on pneumatic applications from Meixner and Kobler (1997 and 1998), and Pinches and Callear (1996). Emergency circuit design is a very broad but yet important section in pneumatic circuit development. Emergency condition can vary from very simple to complex combinations within a single machine. There are no fixed rules or specific methods in emergency circuit design. Therefore the methods presented in the courseware are mainly guidelines in designing the emergency circuit. There are four sub-sections in emergency circuit design namely introduction, emergency circuit design for pure pneumatic, emergency circuit design for electro-pneumatic and safety features. Figure 8 shows one of the emergency circuit designs for pure pneumatics. There are three basic emergency-stop modules in this section, which are basic emergency module, emergency-stop module with multiple emergency input and emergency-stop module with manual and automatic input.

Figure 8: Emergency circuit design for pure pneumatic control


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On the other hand in electro-pneumatics section, there are basically four types of emergency stop conditions shown in the courseware, namely (Figure 9-12):

• System stops and holds its position

• System returns all actuators to the initial position

• System stops and relaxes (pressure is removed and any actuator may be moved)

• System stops and all the actuators move to a given position or in a given sequence

Figure 9: System stops and holds its position


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Figure 10: System returns all actuators to the initial position

Figure 11: System stops and relaxes


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Figure 12: System stops and all the actuators move to a given position or in a given sequence

The emergency circuit design section is presented by using active interactive circuit instead of passive descriptive type of approach. The user would be able to press the emergency stop button at any time and observe the resulting response of the pneumatic cylinders. The emergency circuit design section presented many challenges to the authors. For example, in Stop and Hold circuit design, the circuit would stop and hold the position whenever the emergency button is being pressed. However there are four possible outcomes that will occur in the circuit if the motion sequence is A+, B+, B- and A-. Since it is unpredictable when the user will press the emergency stop button when the cylinders have commenced motion, it increases the difficulty in designing the circuit. The very first step in overcoming the above uncertainty is to analyze the various possible combinations of the emergency conditions relevant to the circuit and prepare all the possible conditions in different time frames. In other words, if the emergency button is being pressed within the first time frames (e.g. between frame 5 and frame 25) the movie will be directed to the first outcome which is A+ for this case and the same thing happens to the other conditions. The last section in the emergency circuit design consists of safety features. Figure 13 shows the simple two-hand starting circuit using pure pneumatic control. A video clip is incorporated in this section to demonstrate the operation and the actual connection of the circuit.


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Figure 13: Video clip for simple two-hand starting circuit In Fundamental Pneumatic Principles section, basic principles such as Pascal’s law are presented together with the definition and some working examples. There are three types of pneumatic components namely compressor, air receiver and pneumatic cylinder presented in Pneumatics Components Sizing Section of the courseware (Figure 14). In the Pressure Loss Calculation Section, different methods in calculating the air pressure drop are presented with the help of interesting diagrams and tables. Formulas for calculating the pressure drop are also incorporated in this section. There is one example added in this section to illustrate the method of using Nomogram to calculate the air pressure drop (Figure 15).


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Figure 14: Pneumatic components sizing section

Figure 15: Pressure loss calculation using Nomogram method Assessments Section is another section in the courseware. It is divided into three sub-sections namely Assessments 1, 2 and 3. Questions in Assessment 1 (Figure 16) are designed for pure-pneumatic circuit control and questions in Assessment 2 (Figure 17) are targeted for electro-pneumatic circuit control. Questions in Assessment 3 (Figure 18) are designed for programmable logic control. Interesting and sophisticated animations in this section help the user in understanding the questions.


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Figure 16: Assessment 1



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CONCLUSION This courseware has been fully developed with rich content and well-built functionality. It has been tested on aspects such as stability, downloading speed and performance of the courseware. There are total of thirteen sections in the courseware namely Introduction to Pneumatics, Fundamental Pneumatic Principles, Sizing of Pneumatics Components, Pressure Loss Calculation, Basic Pneumatics, Types of Pneumatic Control, Circuit Design, Emergency Circuit Design, Pneumatics Symbol Library, Quizzes, Nomenclature, Help and Assessments. Sophisticated animations were incorporated in this multimedia teaching package. It was most widely used in the Assessment section, which allows the user to have a better understanding of the assessment problems. Another feature in this package was the interactive circuits in the Emergency Circuit Section. User will able to see and observe the different outcomes in the control circuit whenever the emergency button is pressed. This is different from the traditional descriptive type of explanation. Two versions of the courseware were created: the CD and the Internet versions. These two have exactly the same content with differences only in some functionality and additional files uniquely created for each.

ACKNOWLEDGEMENT The authors wish to thank the following persons who have contributed significantly to the completion of this work: Mr Tok Yew Gem and Mr Tjahjadi A.J.


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REFERENCES Heins, T. and Himes, F. (2002) Creating learning objects with Macromedia Flash MX, Macromedia White Paper. Kho Chee Loon, (2003). E-learning of Pneumatics, Project Report, School of Mechanical and Production Engineering, Nanyang Technological University, Singapore. Meixner, H. and Kobler, R. (1978). Introduction to Pneumatics, Festo Didactic. Meixner, H. and Kobler, R. (1977). Maintenance of Pneumatic Equipment and Systems, Festo Didactic. Mohler, J. L., (2002). FlashTM MX Graphic, Animation, & Interactivity, Delmar Learning. Pinches, M.J. and B. J. Callear, B.J. (1996). Power Pneumatics, Prentice Hall, Europe. Tieh, S.F. and Lee, K.S. (2002). Development of a Web-based e-Training Courseware in Pneumatic Circuitry for NTC-3 in Mechanical Servicing, Journal of the Institution of Engineer, Singapore Vol. 42, No. 5. Tjahjadi, A.J. (2002). A Multimedia Teaching Package in Pneumatics, Project Report, School of Mechanical and Production Engineering, Nanyang Technological University, Singapore. Tok Y.G., (2001). Further Development of a Multimedia Teaching Package in Pneumatics, Project Report, School of Mechanical and Production Engineering, Nanyang Technological University, Singapore. Trade & Technical Press Ltd, (1980). Principles of Pneumatics, Trade & Technical Press LTD, 1980. Tyler, D. and Rebholz, G. (2001). How to use Macromedia Flash 5, Sams Publishing.

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