International Engineering and Natural Sciences Conference (IENSC 2019) 6- Oral Presentation / Full Text 608 A REVIEW ON NONLINEAR CONTROL APPROACHES: SLIDING MODE CONTROL, BACK-STEPPING CONTROL AND FEEDBACK LINEARIZATION CONTROL Fadi Alyoussef*1, Ibrahim Kaya 2 *1 Electrical and Electronics Eng. Dept., Institute of Natural and Applied Sciences, Dicle University, 2 Dicle University, Electric & Electronics Engineering Department, ikaya@dicle.edu.tr The main goal of this short survey is to provide the reader with recent research directions related to sliding mode control, back-stepping control and feedback linearization control. In fact, the aforementioned nonlinear control techniques have been played an important role in modern control theory due to their potentials to cope with the inherent nonlinearity in most practical engineering it is important to acquaint the reader with the last research trends in this domain. This review is restricted only to study some important papers in IEEE journals about the above-mentioned nonlinear control schemes during the first ten months of 2019 year because there is an explosion in the number of publications in this field which has complicated our mission to highlight all of them. As a matter of fact, it is enough to know that more than 140 papers related to control approaches to be reviewed have been released over a span of ten months only in IEEE journals. Finally, this brief review also gives some mathematical background and some examples about the surveyed controllers. Key words: Nonlinear systems, sliding mode control, Back-stepping control, feedback linearization control, Van der Pol system. 1. Introduction Nonlinear control systems have a promising future because many aspects of nonlinear theory have to be developed for meeting the design requirements in many nonlinear systems [1]. Cyber- physical systems [2], communication [3, 4], energy [5], health care [6-8], big data research [9], robotic systems [10], small unmanned aerial vehicles (UAVs) [11], and AC electrical motors [12] are examples of nonlinear theory applications. History speaking, the first nonlinear governor was designed in the 18th century for controlling steam engine [13, 14]. Generally, the history of nonlinear control theory can be broken down into three eras which contained theories directly or indirectly contributed to the advances in nonlinear control theory [13]. The first era (1880s to 1950s) witnessed several authoritative works related to the concepts of the limit cycle and the phase plane method by Poincare [15, 16], stability analysis of dynamical systems by Lyapunov [17], studying the limit cycle of oscillator dynamics by Van der Pol [18], bode plotting of frequency response by Bode [19], describing function method by Krylov and Bogoliubov [14], feedback theory by Nyquist [20], absolute stability [21], accurate evaluation of limit cycles in relay systems in the time and frequency domain by Hamel and Tsypkin [22, 23] and finally sliding mode control (SMC) by Emelyanov [24]. The second era (1960 to 1989) was considered as the start of modern nonlinear control. Here, many theories have been developed such as chaos theory [25] and butterfly effect [26] by Edward Lorenz, systems and to guarantee the stability of nonlinear systems over a wide operating range. Therefore,