Remote Web-based Control Laboratory for Mobile Devices based on EJsS, Raspberry Pi and Node.js*

This paper presents a new approach to develop remote practices for Systems Engineering and Automatic Control laboratories based on Easy JavaScript Simulations (EJsS), Raspberry Pi and Node.js. EJsS is used to create a JavaScript and HTML5 laboratory front-end that lets teachers and students parametrize and observe the behavior of the controllers/systems under study from the web-browsers of their tablets and smartphones. The Raspberry Pi, a low-cost single-board computer, is in charge of running 1) the C program that closes the control loop over the selected plant and 2) the JavaScript laboratory web server that hosts the laboratory front-end and communicates it with the controller. Finally, the JavaScript development and runtime platform Node.js is used 1) to develop and run the Javascript laboratory web sever within the Raspberry Pi and 2) to support the communications between the laboratory front-end and server. The new strategy, tested over a Proportional/Integral/Differential (PID) controller for a vertical mono-rotor plant, provides low-cost real-time support to the controller and friendly remote access from mobile devices to the practices for the students.