Web-based Learning and Instruction Support System for Pneumatics Chiaming Yen and Wu-Jeng Li Department of Mechanical Design Engineering National Huwei Institute of Technology Yulin (632),Taiwan, R.O.C. Email:
[email protected],
[email protected]
Fax: (886-5) 6328863
Abstract This research presents a web-based learning and instructional system for Pneumatics. The system includes course material, remote data acquisition modules, and a pneumatic laboratory set. The course material is in the HTML format accompanied with text, still and animated images, simulation programs, and computer aided design tools. The data acquisition modules of the system can be connected through the computer I/O with actual devices to verify and implement simulation results to enhance the corresponding Pneumatics learning. Therefore, this web-based learning and instruction support system can be used to assist the Pneumatics instruction, computer aided sequential control design and pneumatic laboratory practice. The course material is organized by chapters and sections, leads users from pneumatic devices to pneumatic systems. Programmable logic controller, PC-based sequential control, internet remote monitoring, and web-based sequential control are also covered. In this study, combinations of software devices and hardware system circuit were used to demonstrate the motion of controlled system. To assist instruction for a Pneumatics course, computer-aided pneumatic circuit design software and computer-aided electric circuit design software were fully integrated. In combining with the remote data acquisition modules, the web-based sequential controller can be used to conduct pneumatic experiment. To gain consistency, this instructional system is mounted on a previously developed instructional platform. Under this Java-based platform, users can apply the communication tools of the platform to gain efficiency while in a non-co-located multiuser session. A database server is used to store circuit designs for all users. And, because the software has collaborative function, it allows all users to design on same circuits collaboratively. 1
Key words: Pneumatics, Ladder Diagram, Sequential Control, PLC 1.
Introduction
Over the past few years, there has been a considerable growth in the use of educational materials over the World Wide Web (WWW). While remaining as a super database of information by connecting the world together with the aid of a user-friendly WWW interface, the Internet is being transformed into a brand new educational model for almost every business sectors. This trend was even leading toward the changes of human’ s way of life. Internet is not only full of rich media in text, images, animation, video, audio, etc. formats, but providing various tools to assist communication among users. These tools include File Transfer Protocol, Electronic Mail, ARCHIE, WAIS, TELNET, SNNP, On-Line Chat, Bulletin Board, Discussion Group, Digital White Board, On-line Meeting, Web Phone, Web Fax, Web Radio, Chat Room, Virtual Reality, etc. Most of these tools can be further integrated with the Internet to become an efficient instruction environment. This development also encourages more educators to dive into these emerging markets. Due to the popularity of the Internet use, most instructors apply the network to host their teaching materials. During the process, in order to gain further advantage of digitalization, most lecturing processes such as web-bases exam, web-based registration, web-based learning evaluation, etc. are further incorporated with the WWW. Therefore, lots of Internet oriented instruction tools were developed [1-5]. These developments also provide boundless space for most education reforms. Some of these tools were further integrated into web based instruction systems. These systems are usually named WBI (Web Based Instruction), IBT(Internet Based Training), or WBT(Web Based Training). Since 1996, a lot of similar systems were created among academic and business incorporation parties. Due to the variety of these systems, various rating sites were show up to guide the users for selection [6]. Previously, our research group developed one set of web based instruction management system. This system is called TeachWEB[7]. During these years, more and more instruction materials were created and incorporated with this system. The study in this paper is to develop web-based instruction materials on Pneumatics for TeachWEB. These include creation of various software programs and integration of pneumatic hardware to assist participants in conducting lectures and learning process efficiently. The main objective of this paper is to support and extend the instruction of classes with laboratory hours for students to conduct experiments. In order to meet the increased demand beyond the laboratory hours, the web-based instruction system combined pneumatic software and hardware was created. By using this system, students can learn with self-paced and well-customized mode. The instructors can also maintain the web-based contents through the web browser with efficient. 2
2. Architecture of
the System
Figure1. Architecture of the web-based instructional system for Pneumatics In this study, a fully interactive instruction system is created for Pneumatics course. Figure 1 shows the architecture of the system. This instruction system is integrated with a web based instruction platform (NHITWeb). Since the courseware is hosted in our instruction system, all the instruction tools can be used to facilitate the course. The instruction platform is written in java servlet, jsp, and jdbc techniques [8][9]. The web-based application is run under Apache web server. The Java servlet is run under Tomcat servlet container [10], and is fully integrated with the Apache web pages to achieve multi-tier application service deployment. The Pneumatics courseware is oulined into chapters from introduction of pneumatic devices to pneumatic circuits. It also covers some advanced topics, such as sequential control, programmable logic controller, PC-based sequential control, and web-based remote control. In the courseware, text, plots, figures, and animation are used to assis the lecturing of the course. During the pneumatic circuit section, the computer-aided pneumatic circuit design software is introduced (Virtual Pneumatic Lab). In the sequential control portion, the web-based sequential control design software is introduced (WebLadderCAD). To further integrate the hyper-linked text and multimedia materials, all the teaching materials can be viewed with a web browser. This web-based courseware is not only mutual interactions but allowing multi-user to collaboratively work on one pneumatic control process design through the use of a collaborative Server. This function can be used as a long-distance lecturing tool. All of the design results can be stored into the separate MS SQL RDBMS system for future reference. 3
A NAP7000 remote data acquisition system is integrated with WebLadderCAD to achieve the web-based sequential control environment. All web-based design results can be used to drive the real corresponding pneumatic system through the hardware connections. This establishes a web-base on-line real-time pneumatic laboratory platform and can be further combined with on-line camera to achieve remote monitor system for non-co-located pneumatic lab system. In addition to the Pneumatic course material, WebLadderCAD simulation component and remote data acquisition system, a web-based Content Management System (CMS) was integrated into the system to allow users maintaining their instructional content through web browser. This CMS system screenshots are given in Figure 2 and 3.
Figure 2 Web-based CMS in File and Directory Manipulation Mode
Figure 3 Web-based CMS in File Edit Mode 4
Under this CMS, instructors can setup different teaching content material by using common virtual Pneumatic simulation components. The instructors can also designate circuit design questions to any registered user and monitor their design work thoroughly using the web browser interface. 3. Introduction of The Cyber University system
Figure 4. NHITWeb instruction management system In this section, all the mentioned subsystems are further integrated into the NHIT Cyber University Platform (NHITWeb) [7] to become a Pneumatic courseware. This platform not only allows users to host coursewares, but also provides functions such as user management, on-line communication tools, and allow instructors to track the learning efficiency of the students. To achieve this study track process, all the student web-based directories were designed to be under the supervision of the instructors, shown as Figure 5. Therefore, the teacher can enter into all the students’working area to grade their works, track their learning results, or provide assistance as necessary.
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Figure 5 Students Web-based Directories Under the Supervision of Instructors For the past few years, the NHIT Cyber University system is designed to become an efficient web-based Pneumatics learning and support system. For most of the involved classes, the traditional meetings and hand-on laboratory still play as a major role to conduct the corresponding Pneumatics lecturing. Besides the regular class lecturing and practice, more and more tools are regularly added to enhance the interaction among participants and hope to provide a personalized learning environment to achieve better results. In summary, the web-based instructional management system consists of the following functions: 1. Session tracking: All functions are integrated. A user only needs to login once. The system will then give different responses based upon the status of the user. 2. Data query: A user can search courses, instructors, course materials, book dealer data and any other teaching related information. 3. Personal data update: Each participant can update their own personal data by on-line editing or upload file from client computer, this includes user’ s personal photo. 4. Synchronous or asynchronous communicating tools: The system provides various web-based communication tools like bulletin board, discussion group, chat room, electronic white board, email, etc. to enhance learning. 5. Course registration: All learning actions start from the user signing in one of the on-line courses. Instructors will have all the action logs for all the sign-in students. 6. Join Classes: The student can remotely join the registered courses or use the system to search for the 6
available courses. 7. Notebook: Each course provides on-line notebook area for students and tutors to take notes while taking any on-line course. 8. Name calling: For synchronous course, teacher can use mouse to perform name calling by listing names of the on-line students and to ask students for on-line responding. During the synchronous course schedule, all students attending records will keep as teacher’ s evaluation reference. Students can also check their attending records. 9. Examination: Tutor can upload an examination file or design a test sheet on-line to set up a designated exam schedule and ask student to conduct the exam on-line. After students send out answers, they will get the exam answers right away on the web. 10. Homework: Student can turn in his homework by uploading or editing the home on-line. The tutor can rank the homework on-line and give back the rank results. 11. Score: Tutor gives the score on-line and the students can check their score through the web browser. 12. Web hosting: Every user gets an on-line account to host his home pages to either editing on-line or upload web pages into the system. 13. Teaching evaluation: At the end of the class, each student can evaluate the instruction performance by filling up the on-line evaluation form. Afterwards, Tutor will get the evaluation results. 14. Full-text search: Participants can use the system on-line full-text search to search for interested materials provided by the system. 15. Learning habit logs: All the learning history will be saved to give the tutor to track the learning habit for most students and teaching material hit records. The tutor can modify the lecturing materials based upon the logs to get improvement. 16. Materials update: The authors can modify any teaching materials they provided 17. Logout: The users are forced to logout after class. This will also prevent other users from entering into the system without permission. The design principle of this instructional management system is to provide user-friendly 7
interface, intelligent response for different user, and automatic data maintain to reduce the burden of the system administrator. The courseware for Pneumatics in his research is mounted on this instructional management system. All the functions listed above become part of the functions of the instructional system for Pneumatics. Figure 4 shows the instruction platform login system. 4. Courseware for Pneuamtics
Figure 6. Courseware for Pneumatics（text、graphic、animation） This courseware is outlined by chapters and was covered from the basic pneumatic principal up to the more advanced sections which including the introduction of components and control circuit design, programmable logic control, pc-based sequential design, internet-based remote monitor, and concluded with web-based sequential control. The courseware contains text, figures and animations (see Figure 6). Besides, there are some software components written by java language to introduce the pneumatic devices. These components can be assembled into pneumatic circuits to represent the dynamic characteristics of control circuits (see Figure 7). These software components can be further combined with user-friendly interface to become web-based computer aided pneumatic circuit design software with the functions of circuit analysis and dynamic simulation. It can be regarded as virtual pneumatic laboratory (see figure 9).
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Figure 7. Dynamic demonstration of pneumatic circuit
Figure 8. Dynamic demonstration of pneumatic-electric circuit control system Similarly, in the electric circuit section, software components are used to simulate electric devices. These components are assembled into electric circuits. Pneumatic circuit and electric circuit together are used to demonstrate the controlled situation of a controlled pneumatic system (see Figure 8). The pneumatic and electric components are combined with user-friendly interface to become a full functional web-based computer aided sequential control design software (WebLadderCAD) (see figure 10) with simulation function. WebLadderCAD is used in sections on sequential control and PLC. WebLadderCAD can 9
output PLC commands according to the circuit design and it can be used as remote monitoring tool. Lastly, it can drive the remote data acquisition system to perform real control. The courseware is hosted in a web server to allow for multi-user. The computer-aided design tool in web page can be used in on-line exam or homework. All design data can be saved in a database server. Besides, a collaborative server on server side allows users to conduct the control system design simultaneously and collaboratively. 5. Virtual pneumatic laboratory
Figure 9. Virtual pneumatic laboratory The virtual pneumatic laboratory [11](see Figure 9) as described before, is a multi-user collaborative computer aided pneumatic circuit design system. This system has the following functions: 1. Visual pneumatic components: All pneumatic components are represented by pneumatic symbols. 2. Computer-aided design: User clicks on the icon to use the component. The components chosen can be assembled into a pneumatic circuit. 3. Animated simulation: The pneumatic components and pneumatic circuit are simulated in real time. 10
4. Data storage: Users can save their designs on the web-based RDBMS. A Java servlet program on server side manages data storage. Design data are transferred to the servlet through applet-servlet communication. 5. Collaborative environment: With a collaborative server, users can design the same pneumatic control system collaboratively with the CAD applet. To use the software, user picks components needed, completes the necessary connections to form pneumatic circuit. Then, the push button can be pressed to activate the control action just like in the real pneumatic system. The controlled consequences are shown animatedly. Better than the real one, the user can view the flow of air, the position switching in a valve. According to the simulation, user can modify the design work until a correct design is reached. In the next section, the virtual pneumatic laboratory is combined with electric components, such as electric switch, conveyor, alarm, and LED signal, etc. to become an electric-pneumatic computer aided control system design software. 6. Computer-aided sequential control design software
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Figure 10. Computer-aided sequential control design software The WebLadderCAD [12] (see Figure 10) is an electric-pneumatic computer aided control system design software. The system has the following functions: 1. Visual controlled system components: The actuators in the virtual pneumatic lab can be used as controlled systems to be actuated by the electric valves. Besides, some electrically controlled components are added. 2. Visual electric components: Electric components are represented by electric symbols. 3. Computer aided electric circuit design: Allow users to use the electric components to form electric circuit. 4. Automatic electric circuit design: User inputs certain motion sequence and sets up an operation mode, the system will automatically complete the electric circuit design work based on the user inputs. 5. Electric circuit analysis: The program will detect the mismatches. 6. Animated simulation: The user can use the animated simulation to check for any possible error. 7. PLC codes: The program can export PLC codes according to the circuit design. 8. Data storage: 9. Collaborative environment: Figure 10 shows a sequential control example; the user first forms a pneumatic system controlled by electric valves and limit switches. For the second step, the motion sequence window can be used to input the required motion sequence. During this process, the electric circuit can be automatically designed. The last step is to simulate the design system to evaluate the electric circuit design for correctness. Figure 10 shows a snapshot during this simulation process. 7. Web-based sequential controller In order to let this instructional system communicate with the real experimental works, a NAP7000 remote data acquisition system [13] is integrated with WebLadderCAD to create a web-based sequential controller [14]. The controller is applied in real pneumatic laboratory to control the genuine pneumatic system in a laboratory as shown in Figure 11.
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Figure 11. Electro-pneumatic sequential control experiment Since this courseware is hosted on a WWW server. The NAP7000 remote data acquisition system is linked on the computer which server the web pages to perform PC-based sequential control. The user can use the web browser in client-side to design the control system and perform test drive in the server-side control laboratory. The server-site control and measurement data can then be transmitted to the client-side computer to show the control status. A web-based remote monitor system is now established (see Figure 12). This system can be linked with video streaming system to monitor the real-time image of the remote-site.
Figure 12. Electro-pneumatic system remote control 13
8. Results
Figure 13. Homepage of courseware for Pneuamtics Figure 13 shows the portal system for this courseware [15]. The user needs to connect with the NHIT Cyber University (see Figure 4) and sign-in this pneumatic on-line course to join the course. Figure 6, Figure 7, and Figure 8 are typical snapshots of the courseware, which provide animated demonstration and interaction (user can push the start button to activate the motions of the pneumatic system.). Figure 9 and Figure 10 are main design tools in the courseware. And Figure 11 and Figure 12 are examples of the real-time pneumatic experiments. This instructional system for Pneumatics is an interactive web-based instructional environment that provides self-paced learning on Pneumatics course. With the growth and popularity of the World Wide Web, more and more traditional lecturing can take advantage of the like online educational tools. During the trial test of the system, the following benefits were reached by applying these systems to related Pneumatics courses: (1) By applying the web-based simulation system, students can conduct lab practice beyond the class meeting hours, the management of the lab classroom became easier. (2) All the homework circuit designs can be double checked before turn in. (3) Project based homework can be prepared and conducted non-co-located among team members. (4) Since most of the preliminary test runs were conducted on simulation system, fewer sets of the hardware laboratory equipments were required. (5) Self paced learning process for each student can be reached.. This courseware is among the first sets of the interactive courses developed for the NHIT Cyber University system. Although implemented fully interactively and collaboratively, 14
more testing and further studies on learning evaluation still need to be conducted to gain justification and even bigger advantage. Other than these, several projects associated with including study effectiveness analysis, customer relation management and integration with large control systems are on the way. 9. Conclusion This paper designs a web-based instructional system for Pneumatics. It includes course material, remote data acquisition modules, and a pneumatic laboratory set. The course material consists of text, images, animation, demonstration programs, simulation programs, and computer-aided design tools. The remote data acquisition modules and laboratory set are used to conduct real experimental works. The pneumatic experiments can be performed remotely through a web browser. The whole instructional system can be used for instruction, computer aided sequential control design and pneumatic laboratory. Besides multi-media, this instructional system provides highly interactions between course material and users through the use of Java applets embedded in web pages. After several semesters of testing, this system not only proved to ease lab classroom management loading, but also as an efficient Pneumatics learning support system to get better learning results. 10. Acknowledgement This paper was supported by the National Science Council (grant #90-2212-E-150-028) in Taiwan. References 1. WebCT, http://www.webct.com/. 2. Web Tools for Learning, http://webtools.cityu.edu.hk/. 3. The Virtual Chase, http://www.virtualchase.com/Trainers/ . 4. e-Education, http://www.blackboard.com/ . 5. IMS Global Learning Consortium, http://www.imsproject.org/ . 6. ‘ onl i nee duc a t i ona lde l i ve r ya ppl i c a t i ons :awe bt oolf orc ompa r a t i vea na l y s i s ’ , http://www.ctt.bc.ca/landonline/. 7. Wu-Jeng Li，the NHIT Cyber University system (NHITWeb)， http://class.mde.nhit.edu.tw/db/pneu/. 8. Bruce Eckel,” Thi nki ngi nJ a va ” ,2nde di t i on,http://www.mindview.net/Books/TIJ/. 9. Jason Hunter and Wi l l i a m Cr a wf or d” Java Servlet Programming” , 2nd edition, 2001, http://www.amazon.com/. 10. Servlet Container，Tomcat, http://jakarta.apache.org/. 11. Wu-Jeng Li and Chiaming Yen,"A Web-based Computer-aided Pneumatic Circuit Design 15
Software", submitted to Simulation Practice and Theory. 12. Chiaming Yen and Wu-Jeng Li ,"A Web-based Collaborative Computer-aided Sequential Control Design Software", to appear in IEEE Control Systems Magazine, (2003). 13. NAP7000 remote data acquisition system, http://www.icpdas.com.tw/. 14. Chiaming Yen and Wu-Jeng Li,"A Web-based Sequential Controller", 4th Asian Control Conference ASCC 2002, Singapore, 2002.. 15. Wu-Jeng Li, courseware for Pneumatics, http://class.mde.nhit.edu.tw/db/pneu/courseware/.
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