Compensation of Unknown Multiharmonic Disturbance for Nonlinear Plant with Delay in Control* Anton A. Pyrkin, Alexey A. Bobtsov, Sergey A. Chepinskiy, and Yuriy A. Kapitanyuk Department of Control Systems and Informatics, Saint-Petersburg State University of Information Technologies Mechanics and Optics, Kronverkski, 49, Saint-Petersburg, 197101, RUSSIA (e-mail: a.pyrkin@gmail.com, bobtsov@mail.ru, chepinsky_s@hotmail.com, yura.kapitanyuk@gmail.com). Abstract: In this paper a new approach for cancellation of a multiharmonic disturbance is proposed. Compared with a number of known results in this paper the disturbance compensation problem is solved when the output variable is measured only, a relative degree of the plant is arbitrary and the control channel has delay. The numerical example is presented to illustrate theoretical result and the reaction wheel pendulum on a movable platform is considered as the plant to demonstrate that proposed approach is realizable and can be plugged in practice. Created by hand disturbance moves the platform in horizontal surface and the pendulum is oscillating. The second goal of this work is the development of mechatronic applications using in education. I. INTRODUCTION In this article a new approach for rejection of multiharmonic disturbance with unknown parameters acting on a nonlinear plant is proposed. There are a number of papers dealing with control in condition of uncertain disturbance     using only input and output measurable signals. The paper is focused on the design of the adaptive scheme to identify the frequency of the sinusoid. Many different approaches exist for adaptive identification of unknown sinusoid, see, for example, (Aranovskiy et al. (2010), Bobtsov (2008)-Bobtsov et al. (2009), Hou (2005), Hsu et al. (1999), Marino et al. (2003), Xia (2002), Pyrkin et al. (2010)). Some of these approaches are not restricted to the case of a single sinusoid, in particular, a biased sinusoidal signal is considered in (Bobtsov et al. (2005), Bobtsov (2008), Hou (2005)), and the case of multiple sinusoids with different frequencies is presented in (Bodson et al. (1997), Xia (2002)). This approach is based on the ideas introduced in (Bobtsov (2008)-Bobtsov et al. (2009), Nikiforov (1998)) and removes various limitations of these designs. In particular, (Nikiforov (1998)) and (Bobtsov (2008)) deal with a minimum-phase plant, the scheme from (Bobtsov et al. (2008)) is limited to stable plants of relative degree one but for unknown plant, and the result presented in (Bobtsov et al. (2009)) applies to stable plants of arbitrary relative degree. Here, our disturbance rejection scheme applies to plants with non- minimum phase and arbitrary relative degree, while the dynamic order of the adaptive law is equal to three for each harmonic, which compares favorably with known * This work was supported by the RFBR (projects 09-08- 00139-a), the ADTP (project 2.1.2/6326), and the FTP (projects NK-92P/5: P498/05.08.2009, NK-495P/1: P127/13.04.2010). results (Hou (2005), Marino et al. (2003), Xia (2002)). To demonstrate the efficiency of control law that can reject the unknown disturbance in condition of input delay we construct the special mechatronic control kit (see Fig. 1 and Fig. 2) and consider stabilization problem for mechatronic plant represented by the reaction wheel pendulum on movable platform. The disturbance is created by hand moving platform in horizontal plane. Complex of Mechatronics system Inc., disposable of Cybernetics and Control System Laboratory of SPbSU ITMO has been used to demonstrate efficiency of proposed algorithm (see Fig. 1). Fig. 1. Mechatronic Control Kit Fig. 2. Schematic sketch of the pendulum system 8th IFAC Symposium on Nonlinear Control Systems University of Bologna, Italy, September 1-3, 2010 978-3-902661-80-7/10/$20.00 © 2010 IFAC 481 10.3182/20100901-3-IT-2016.00065