Chaos, Solitons and Fractals 104 (2017) 18–27 Contents lists available at ScienceDirect Chaos, Solitons and Fractals Nonlinear Science, and Nonequilibrium and Complex Phenomena journal homepage: www.elsevier.com/locate/chaos Frontiers Dynamics of a pendulum driven by a DC motor and magnetically controlled B. Nana a,∗ , S.B. Yamgoué a , R. Tchitnga b , P. Woafo c a Department of Physics, Higher Teacher Training College, University of Bamenda, PO Box 39 Bamenda, Cameroon b Laboratory of Electronics and Signal Processing, Faculty of Science, University of Dschang, PO Box 67 Dschang, Cameroon c Laboratory of Modelling and Simulation in Engineering, Biomimetics and Prototypes, Faculty of Science, University of Yaounde I, PO Box 812 Yaounde, Cameroon a r t i c l e i n f o Article history: Received 2 January 2017 Revised 23 July 2017 Accepted 31 July 2017 Keywords: Electromechanical Pendulum Magnet Chaos a b s t r a c t The paper is devoted to theoretical and experimental investigations of an electromechanical system con- sisting of DC motor, a physical pendulum with the repulsive magnets. The work consists of modeling, simulation and experimental measurements to validate the analytical predictions and the numerical sim- ulation of the earlier introduced mathematical model. The parameters of the model are estimated using the experimental data. The analyzed system shows several types of non-linear effects, including hys- teresis, jump phenomena, chaos and periodic dynamics. Good agreement between real and simulated behavior of the system is obtained. © 2017 Elsevier Ltd. All rights reserved. 1. Introduction Electromechanical systems play an essential role in fulfilling the needs of modern technological applications. The electrical energy supplied to these systems is transformed into mechanical energy with an efficiency of 80 per cent by electric drives [1]. Physicists are particularly interested in those kinds of the dynamical systems, since they are relatively simple but can exhibit almost all aspects and phenomena of non-linear dynamics. As consequence, the range of technological tasks that need these systems broadens every year. This results in an increasing necessity for more advanced mod- eling, identification and control strategies for these systems. Many applications need a sufficiently concise and accurate description of the dynamics of these systems. This is especially true in au- tomatic control applications. Dynamic models describing the elec- tromechanical system in use can be developed using principles of physics. However, models constructed in this way may be difficult to derive due to lack of sufficient knowledge or uncertainties in system dynamics. Given their numerous applications in engineering, many stud- ies on the nonlinear dynamics of mechanical systems have been ∗ Corresponding author: E-mail address: na1bo@yahoo.fr (B. Nana). URL: http://www.lamsebp.org (B. Nana) made. These mechanical systems are composed of pendulums in different configurations including planetary or spatial pendulums, simple or multiple, and sometimes parametrically excited pendu- lums [2–5]. In some case an experiment is performed in order to confirm analytical or numerical investigations [6–8]. Sometime, in order to achieve a good agreement between the model predictions and experimental data, one must take into account many details concerning physical modeling of the real process [9,10]. Mechanical structures such as models of pendulum-like lever arms and mechanical manipulators are increasingly attracting a lot of attention as their dynamical behavior has shown to exhibit dif- ferent phenomena related to oscillations, bifurcation, and chaos. In the work [12], the authors investigated both numerically and ex- perimentally an electromechanical system driven by a DC motor. The angular velocity of the mechanical part was almost constant because the power of the motor was relatively high. Mathemati- cal modeling of the same system under simplifying conditions was presented in [13]. Electromechanical pendulums have important applications in space exploration, manufacturing automation, construction, min- ing, hazardous operations, and many other areas. Although signif- icant progresses have been made in many aspects over the last one and half decade, many issues are not resolved yet, and fur- ther efforts and results in this area would contribute significantly to robotics, and in particular, automation. Research activities have http://dx.doi.org/10.1016/j.chaos.2017.07.027 0960-0779/© 2017 Elsevier Ltd. All rights reserved.