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A WEB-BASED VIRTUAL CONTROL LABORATORY OF THE INVERTED PENDULUM

E. Pérez, A. Rodriguez, I. Tejado

University of Extremadura (SPAIN)
The combination of information and communications technologies together with computer-based technologies, such as simulations, videos and other interactive tools, when integrated into a system in enhancing teaching and learning, have shown a huge potential in the current education field in the context of the European Space for Higher Education, since both can help students to acquire competences, and consequently, knowledge, which might be even more relevant in the particular case of engineering. Besides that, such advancements can also assist the construction mental models of key concepts through visual representations and realistic simulations, as well as other skills and attitudes [1, 2].

During the last years the interest for the application of interactive resources, such as virtual and remote laboratories, have been spread across most of teaching centres as supporting tools for classical master classes due to the advantages derived by their use with respect to learning outcomes [3]. There exist many tools to develop virtual and remote labs, whose choice mainly depends on the educational field of application. Among them, in control education Easy Java/Javascript Simulations, also known as EjsS (and, formerly, EJS), is one of the most widely-used tool (see e.g. [4]).

In this context, this paper presents a web-based virtual control laboratory for the classical control problem of the cart-pendulum system built in EjsS. This laboratory is aimed to introduce the students of automatic control courses of engineering degrees at the University of Extremadura to linear and nonlinear control strategies for both balance and swing-up control of the system, allowing them not only designing linear quadratic regulators (LQRs) in state space or classical proportional-integral-derivative actions for balance control, but also working with modelling issues: linearization, state space models and transfer functions. For swing-up control, a nonlinear energy control is implemented. Likewise, it is worth remarking that it is also possible to combine several of the strategies above-mentioned. Hence, essentially, the main features of the laboratory developed, in comparison with other existing cart-pendulum interactive tools, are that: several control strategies can be applied to the system, it is also remarkable its capability to be executed in multiple types of devices with Javascript support (PCs, tablets, smartphones) and, finally, the possibility to commute the cart visualization between 3D and 2D, depending on the device’s specifications where the user is executing the laboratory.

References:
[1] R. Kozma, "Will media influence learning? Reframing the debate", Educational Technology Research and Development, vol. 42, no. 2, pp. 7–19, 1994.
[2] L. De la Torre, M. Guinaldo, R. Heradio, S. Dormido, "The Ball and Beam System: A Case Study of Virtual and Remote Lab Enhancement With Moodle", IEEE Transactions on Industrial Informatics, vol. 11, no. 4, pp. 934–945, 2015.
[3] S. Dormido Bencomo, "Control Learning: Present and Future. Annual Reviews in Control", vol. 28, no. 1, pp. 115–136, 2004.
[4] R. Heradio, L. de la Torre, S. Dormido, "Virtual and remote labs in control education: A survey", Annual Reviews in Control, vol. 42, pp. 1–10, 2016.