A Depth Adaptive Global Sliding Mode Control Method for Underactuated Uuv with Uncertain Time-varying Delay

Abstract

The invention provides an indeterminate time-varying and time-lag adaptive global sliding-mode depth control method for under-actuated UUV. The method comprises the steps that 1) the UUV obtains preset state information and receives a depth instruction via a sensor of the UUV itself; 2) a time-varying and time-lag model and a global sliding-mode surface of the UUV are established via the above information and external environment interference information; and 3) based on the time-varying and time-lag model and the designed sliding-mode surface of the UUV, an adaptive global sliding-mode control rate is designed, and depth control for the UUV is realized. The method can ensure accurate depth control for the UUV in the conditions that time-varying and time-lag are indeterminate and external environmental interference exits.

Description

technical field [0001] The invention relates to a depth control method of an under-actuated underwater unmanned vehicle. Background technique [0002] Unmanned underwater vehicle (Unmanned Underwater Vehicle, UUV), with its super maneuverability, long-lasting endurance, comprehensive perception and adaptability to complex environments (such as autonomous navigation, fault diagnosis, etc.), has gradually become the An indispensable and powerful tool in the ocean development process. The precise control of UUV depth is the basic guarantee for the successful completion of tasks such as marine resource exploration and exploitation, seabed topography mapping, and marine environment monitoring. With the steady advancement of UUV intelligence, miniaturization, and functional diversification, the complexity of UUV control systems continues to increase, and the problem of time lag has become increasingly prominent, which makes the design of UUV depth controllers more complicated and...

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Problems solved by technology

However, the above UUV depth control does not consider the system time lag

Bi Fengyang et al. in the literature "Fuzzy variable structure control of model uncertain time-delay under-driven AUV" (Harbin Institute of Technology, 2010, Vol. 42 No. 3) for AUV with time-varying hydrodynamic coefficient, unmodeled dynamics and time-delay, etc. Uncertainty, with the input of the sliding mode surface and its rate of change of the fuzzy controller, the rate of change of the control law of the sliding mode variable structure is the output, the design of the fuzzy sliding mode controller, and the comparison with the simulation of the quasi-sliding mode controller proves that the The robustness of the controller, however, this paper does not consider the time lag when modeling, but only overcomes the time lag of the system through the robustness of the controller. This method is applicable to the case where there is a small time lag in the AUV system , once the time lag of the system is slightly larger, the controller will fail

Yuesheng Luo et al. "Resilient guaranteed cost diving depth control for nonlinear singular time-delay AUV system" (2010Second International Conference on Intelligent Human-Machine Systems and Cybernetics (IHMSC), 2010) established an AUV depth control system for the nonlinear constant time delay of the AUV system A mathematical model with time delay, and an elastic guaranteed energy controller based on the linear matrix inequality, which ensures the stability of the system, but in the actual UUV operation, the time delay of the system is not fixed, but changes with time. changes, so the method is not practical

[0004] The "underactuated UUV vertical plane control method based on T-S fuzzy time-delay model" disclosed in the patent document with application number 201610118633.1 proposes a state feedback controller based on the T-S fuzzy time-delay model, and also only considers the constant time-delay existing in the system problem, lack of practicality

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