In this paper, an observer based sliding mode method is used to control the heart rhythm system. For this purpose, nonlinear and uncertain dynamics of a sick human heart are considered. The output of the three main parts of the heart is assumed to be the output of the controlled system and the electrical signal applied to the three main parts of the heart is also considered as the input vector. Hence the controller is designed using the MIMO sliding mode method. The control signals applied to the three points of the heart are determined in such a way that the electrocardiogram signal behaves desirable. An observer is also used to estimate unmeasurable state variables and uncertain functions of the heart. Continuous approximation method has been used to produce smooth control signals and remove chattering. The simulation results show the good performance of the proposed control system to control the heart rate behavior of a person with tachycardia disease. تفاصيل المقالة

In this paper, the speed control of a permanent magnet synchronous motor is performed in a desired finite time. Due to the nonlinearity of the dynamics of this type of motors and the form of the state equations, a back-stepping strategy has been chosen to design the control system. In the proposed method, in each design step, the finite time stability condition is used, so the nonlinear controller has the ability to guarantee finite time convergence of output tracking error. The finite time stability of the proposed control method is proved based on Lyapunov theory. Adjusting the convergence time of system outputs can be done by changing the gain of the controllers. Furthermore, the proposed controller generates smooth control signal that can be implemented. The simulation results show that the proposed method is able to control the speed and current of a permanent magnet synchronous motor in desired finite time. تفاصيل المقالة