INTERNET BASED REMOTE CONTROL SYSTEM

Abstract

Due to the limitation of Internet technology and network bandwidth, direct computer control via the Internet is still an unsolved problem. This thesis presents a solution to apply supervisory control remotely through the Internet and demonstrates how experiments in control can be performed remotely via Internet/Intranet. The system proposed and developed is general, flexible, extensible, and modular. The infrastructure of the system includes client PCs, web server, database server, local control server, video server, video encoder machine, and the control unit. A solution for real time information delivery, monitoring and control via Internet was proposed to overcome the Internet limitation. User authentication, dynamic scheduling, user queuing, data stornge und data buffering technologies were also studied and discussed in the thesis. A coupled Lank control apparatus was set up as the remote plant to be controlled. The coupled tank was configured as a second-order single input single output plant. The objective is to control the water level in the second tank by manipulating the village to the pump of the first tank. Local control software was developed and open-loop control, PID control, and frizzy logic control algorithms have been implemented in verify the control system design. Remote control and data communications among users, web server, local control server were studied and developed based on TCP/IP. The same control can be performed remotely through Internet. To successfully transfer data in 'real time' (with delay) through Internet, researches on limitation of TCP/IP, producer-consumer issue in real time system, Internet client pull and server push technologies have been conducted. An ActiveX control that runs within the browser was developed. Data buffers were also designed within the database server. Data communication interrupted, data lost and connection lost problem have been solved using the above solution. Internet video broadcasting technology (unicast and multicast) was also studied and a solution based on Microsoft NetShow technology was implemented to transfer streaming MPEG4 video to multiple users. The effect of different transfer rate and video size was tested in both Intranet and Internet. The Internet Based Remote Control System keeps track of every user after he/she logs on to the system. The results of the control (control parameters, control signal and control system response) were stored in a SQL server database. An on-line report system was developed and both user and lecturer can view the experiment report. Users can also download control data for their own analysis.