scholarly journals Control Technology of Ground-Based Laser Communication Servo Turntable via a Novel Digital Sliding Mode Controller

2019 ◽  
Vol 9 (19) ◽  
pp. 4051 ◽  
Author(s):  
Jianqiang Zhang ◽  
Yongkai Liu ◽  
Shijie Gao ◽  
Chengshan Han
Keyword(s):  
Sliding Mode ◽  
Variable Structure ◽  
Laser Communication ◽  
Adaptive Function ◽  
Initial State ◽  
Digital Pid ◽  
Nonlinear Disturbance ◽  
Sliding Mode Variable Structure ◽  
Servo Turntable ◽  
Smooth System

In this study, a sliding mode control (SMC) algorithm was proposed based on a novel reaching law to solve the nonlinear disturbance problem of a ground-based laser communication turntable. This algorithm is a chatter-free method, in which the coefficient of sliding mode variable structure function is designed as an adaptive function, so the chattering of the sliding mode approaches zero. For any perturbed system, this algorithm can ensure a finite time for the system state to reach the sliding mode surface from any initial state. Additionally, the system will stabilize in the quasi-sliding mode domain (QSMD) with O(T3) width, where a narrower QSMD width corresponds to stronger robustness toward nonlinear disturbances. Both mathematical calculations and simulations verified the sliding mode and stability of this control algorithm. Experimental results of the velocity closed-loop of pitch axis show that the proposed algorithm effectively improved the anti-nonlinear disturbance ability of the control system compared with the effects of the traditional digital PID and the existing chatter-reduced SMC algorithms, for smooth system operation.

Sliding Mode Control of a Welding Mobile Manipulator

2011 ◽  
Vol 347-353 ◽  
pp. 3211-3214
Author(s):  
Hong Mei
Keyword(s):  
Sliding Mode Control ◽  
Trajectory Tracking ◽  
Sliding Mode ◽  
Variable Structure ◽  
Convergence Speed ◽  
Mobile Manipulator ◽  
Initial Error ◽  
Initial State ◽  
Strong Robustness ◽  
Sliding Mode Variable Structure

A new sliding mode variable structure controller is proposed. First, aiming at improving the convergence speed, a new nonlinear sliding mode surface is proposed. Then, the initial error speed is designed to make the initial state of the system to be just on the sliding mode surface which is to impair the chattering and improve the robustness of the controller. Finally, a mobile manipulator with two arms is taken as an example to simulate the trajectory tracking with the proposed controller. It is found that system shows high convergence speed and strong robustness against disturbance. The chattering is also impaired greatly.

scholarly journals Synchronous Generator Rectification System Based on Double Closed-Loop Control of Backstepping and Sliding Mode Variable Structure

Electronics ◽  
2021 ◽  
Vol 10 (15) ◽  
pp. 1832
Author(s):  
Jinfeng Liu ◽  
Xin Qu ◽  
Herbert Ho-Ching Iu
Keyword(s):  
Closed Loop ◽  
Control Structure ◽  
Low Voltage ◽  
Sliding Mode ◽  
Variable Structure ◽  
Synchronous Generator ◽  
Closed Loop Control ◽  
High Current ◽  
Loop Control ◽  
Sliding Mode Variable Structure

Low-voltage and high-current direct current (DC) power supplies are essential for aerospace and shipping. However, its robustness and dynamic response need to be optimized further on some special occasions. In this paper, a novel rectification system platform is built with the low-voltage and high-current permanent magnet synchronous generator (PMSG), in which the DC voltage double closed-loop control system is constructed with the backstepping control method and the sliding mode variable structure (SMVS). In the active component control structure of this system, reasonable virtual control variables are set to obtain the overall structural control variable which satisfied the stability requirements of Lyapunov stability theory. Thus, the fast-tracking and the global adjustment of the system are realized and the robustness is improved. Since the reactive component control structure is simple and no subsystem has to be constructed, the SMVS is used to stabilize the system power factor. By building a simulation model and experimental platform of the 5 V/300 A rectification module based on the PMSG, it is verified that the power factor of the system can reach about 98.5%. When the load mutation occurs, the DC output achieves stability again within 0.02 s, and the system fluctuation rate does not exceed 2%.

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