scholarly journals Prescribed Performance Control for Two-axis Optronic Stabilized Platform

2018 ◽  
Vol 160 ◽  
pp. 01003
Author(s):  
Wang Yexing ◽  
Luo Changxin ◽  
Zhang Tao ◽  
Liu Yaning ◽  
Xiao Chuhan
Keyword(s):  
Closed Loop ◽  
Initial Error ◽  
Closed Loop System ◽  
Performance Function ◽  
Performance Control ◽  
Prescribed Performance ◽  
Initial Errors ◽  
Prescribed Performance Control ◽  
Unknown Disturbance ◽  
Stabilized Platform

Aiming at improving the tracking and stabilizing performance of two-axis optronic stabilized platform with Stribeck friction and uncertain velocity disturbance, a prescribed performance control strategy with unknown initial errors is designed. By designing a new performance function, the limit of traditional prescribed control that the initial error has to be known accurately is broken through. The strategy possesses strong robustness against unknown disturbance, and the state error is restrained to a predefined arbitrary small residual. It is guaranteed that the closed-loop system is uniformly ultimately bounded. The simulation results demonstrate the effectiveness of proposed strategy.

scholarly journals Robust Trajectory Tracking Control of Underactuated Surface Vehicles with Prescribed Performance

2020 ◽  
Vol 27 (4) ◽  
pp. 148-156
Author(s):  
Shasha Wang ◽  
Yulong Tuo
Keyword(s):  
Closed Loop ◽  
Sliding Mode ◽  
Tracking Errors ◽  
External Disturbances ◽  
Trajectory Tracking Control ◽  
Performance Function ◽  
Prescribed Performance ◽  
Performance Constraints ◽  
Initial Errors ◽  
Control Scheme

AbstractIn this paper, a robust sliding mode tracking controller with prescribed performance is developed for an underactuated surface vehicle (USV) with time-varying external disturbances. Firstly, to guarantee the transient and steady-state performance of the closed-loop system, the error transformation technique is presented. Further, the design of the prescribed performance function implements predefined tracking performance constraints, which eliminate the requirement for prior knowledge about the initial errors. Then, a Lyapunov stability synthesis shows that all closed-loop signals remain bounded and the tracking errors remain strictly within the predefined bounds. Finally, simulations and a comparative study are performed to illustrate the robustness and effectiveness of the proposed robust sliding mode control scheme.

scholarly journals Variable Gain Prescribed Performance Control for Dynamic Positioning of Ships with Positioning Error Constraints

2022 ◽  
Vol 10 (1) ◽  
pp. 74
Author(s):  
Chenglong Gong ◽  
Yixin Su ◽  
Danhong Zhang
Keyword(s):  
Closed Loop ◽  
Input Saturation ◽  
Control Law ◽  
Positioning Error ◽  
Performance Bounds ◽  
External Disturbances ◽  
Performance Control ◽  
Prescribed Performance ◽  
Variable Gain ◽  
Prescribed Performance Control

In this paper, a variable gain prescribed performance control law is proposed for dynamic positioning (DP) of ships with positioning error constraints, input saturation and unknown external disturbances. The error performance index functions are designed to preset the prescribed performance bounds and the error mapping functions are constructed to incorporate the prescribed performance bounds into the DP control design. The variable gain technique is used to limit the output amplitude of the control law to avoid input saturation of the system by dynamically adjusting the control gain of the DP control law according to the positioning errors, and the error mapping function replaces the positioning error as a recursive sliding-mode surface to realize the prescribed performance control of the system and guarantee the stability of the closed-loop system with variable control gains. It has been proved that the proposed DP control law can make the uniformly ultimately boundedness of all signals in the DP closed-loop control system. The numerical simulation results illustrate that the proposed control law can make the ship’s position and heading maintain at the desired value with positioning error constraints, enhance the non-fragility of the DP control law to the perturbation of system’s parameters and improve the system’s rejection ability to external disturbances.

scholarly journals Composite Learning Prescribed Performance Control of Nonlinear Systems

Complexity ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Fang Zhu ◽  
Wei Xiang ◽  
Chunzhi Yang
Keyword(s):  
Tracking Error ◽  
Original System ◽  
Feedback System ◽  
Closed Loop System ◽  
Performance Control ◽  
Prescribed Performance ◽  
Persistent Excitation ◽  
Prescribed Performance Control ◽  
Control Scheme ◽  
The Stability

This paper investigates a composite learning prescribed performance control (PPC) scheme for uncertain strict-feedback system. Firstly, a prescribed performance boundary (PPB) condition is developed for the tracking error, and the original system is transformed into an equivalent one by using a transformation function. In order to ensure that the tracking error satisfies the PPB, a sufficient condition is given. Then, a control scheme of PPC combined with neural network (NN) and backstepping technique is proposed. However, the unknown functions cannot be guaranteed to estimate accurately by this method. To solve this problem, predictive errors are defined by applying online recorded date and instantaneous date. Furthermore, novel composite learning laws are proposed to update NN weights based on a partial persistent excitation (PE) condition. Subsequently, the stability of the closed-loop system is guaranteed and all signals are kept bounded by using composite learning PPC method. Finally, simulation results verify the effectiveness of the proposed methods.

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