Utilizing sliding mode control for the cavitation phenomenon and using the obtaining result in modern medicine

Abstract

The existence of a bubble in the vicinity of an elastic boundary appears in many situations such as medical and mechanical systems. On the other hand, bubble collapse is considered a source of energy loss in most systems and caused a lot of damages to it. This research is the first attempt to prevent bubble collapse in the vicinity of an elastic boundary by using control algorithms. In this paper, first, the nonlinear dynamic model of bubble in the vicinity of an elastic wall is introduced and then rewritten into state-space form. The second part of this paper is devoted to the design of the sliding mode controller for the bubble system, where the ultrasonic pressure plays the role of control input and the output is the bubble radius. Our main objective is to design a stabilizing controller that is able to regulate the radius of the bubble to the desired radius. At first, traditional sliding mode controller is proposed. Despite the successful tracking error, the chattering problem of this method leads us to introduce the boundary layer sliding mode control. Although the chattering phenomenon has been attenuated, it increases the steady-state error. Finally, robust integral sliding mode control is suggested to minimize the steady-state error while the chattering problem is removed. Numerical simulations including the case of parametric uncertainty are also presented. The results of this study are of immediate interest for medical applications such as ultrasound imaging and also industrial applications such as designing long-lasting pumps and valves.

Radial basis function neural network based second-order sliding mode control for robotic manipulator

“…This problem is also tried to be solved by the boundary layer method. [13][14][15] Using the saturation function instead of the switching function can weaken the chattering phenomenon, but the selection of the boundary layer thickness is difficult and may affect the system performance and robustness. At present, the most effective method to weaken the chattering problem is the super-twisting algorithm (STA) in high-order sliding mode control, which can produce continuous control signals and has attracted the attention of many scholars.…”

“…Motivated by the above discussion, considering the model error and external disturbance, a new adaptive second-order terminal sliding mode control method based on RBF neural network is proposed. The main contributions of this paper are as follows: (1) Compared with references, [11][12][13][14][15] the proposed control law is continuous without discontinuous high-frequency switching term, which effectively weakens the chattering and ensuring the robustness of the system. And compared with references [16][17][18][19] , the control method is not affected by the relative order of the system, which can greatly improve the practicability of the method.…”

Design of an adaptive nonsingular terminal sliding mode using supervisory fuzzy for the output voltage control of a buck converter

“…Because of the simple structure and robust behavior against parametric uncertainty and external disturbances, the sliding mode control (SMC) has become a popular method. SMC has been applied successfully to a variety of systems such as medical systems (Badfar & Ardestani, 2019;Badfar, Ardestani, & Beheshti, 2020), mechanical systems (Amirkhani, Mobayen, Iliaee, Boubaker, & Hosseinnia, 2019;Bessa, Otto, Kreuzer, & Seifried, 2019;Peza-Solis, Silva-Navarro, & Castro-Linares, 2015) and electrical converters (Asgari, 2019;Li, Liu, & Su, 2019). Recently, the terminal sliding mode control (TSMC) has been introduced to guarantee the finite-time convergence and higher precision of tracking error (Du, Chen, Wen, Yu, & Lü, 2018).…”