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

Abstract

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.

The Effective Chattering Suppression Technique with Adaptive Super-Twisted Sliding Mode Controller Based on the Quasi-Barrier Function; An Experimentation Setup

“…In the presented experiment, the chattering phenomena are also caused by the digital implementation of the algorithm. The discrete implementation of SMC is called the quasi-sliding mode, and the chattering phenomena are proportional to the sampling period [34]. In the experimental results, the influence of the sampling time is effectively reduced.…”

Advances in Mechanical Systems Dynamics

“…The first is related to laser communication, while the second is related to the control of flow separation in axial compressors. In the first paper [25], the design of a sliding mode controller to solve the nonlinear disturbance problem of a ground-based laser communication turntable is discussed-indeed, the alignment of the platform is a key issue in this field. Experimental results on the pitch closed-loop behavior show a better performance of the proposed (chatter-free) controller when compared to the traditional proportional, integrative, derivative (PID) and existing sliding mode.…”

Event-Triggered Second-Order Sliding Mode Controller Design and Implementation

“…Several studies address chattering phenomena and analyze different methods for their suppression. For example, the second-order sliding mode controller, known as the super-twisted algorithm (STA), was a subsequent solution to reduce output oscillation by placing the nonlinear term behind the integrator, ensuring continuous output and preserving the properties of the first-order SMC [41,42]. Regarding work [43], the chattering phenomena can be suppressed effectively only for first-and second-order systems, where the parasite dynamics are not considered.…”

“…Regarding work [43], the chattering phenomena can be suppressed effectively only for first-and second-order systems, where the parasite dynamics are not considered. The chattering phenomena alleviation with the digital implementation of the SMC controller attracts the interest of scholars [41,[44][45][46][47][48].…”