Fuzzy Sliding Mode Control Method Of AUVs

Autonomous underwater vehicle (AUV) are unmanned ocean carriers able to move and operate through independent way underwater, can be used as undersea probes, underwater weapons and deep ocean resources development tools. AUV have very broad application,represents the future direction of underwater vehicle technology. The control problem of AUV with features as nonlinear model, time-varying and strong coupling, need to overcome the random perturbations bring by complex underwater environment. So, the robustness and anti-interference ability of the control method is the key to achieving autonomy.In this paper, the control of AUV conducted a series of studies, work as follows:First, learn fuzzy control, sliding mode control and fuzzy sliding mode control.research suitable control strategy for AUV: in order to improve the performance of fuzzy control, using auxiliary fuzzy control adjustment factor, proposed a fuzzy self-tuning control method based on fuzzy switch gain adjustment; in order to weaken the chattering phenomenon of sliding mode control, using the output of the fuzzy control as a sign function switching key to soften the control signal, proposed a switching fuzzy variable structure control method.Secondly, to build AUV 6-DOF underwater space motion mathematical model, include kinematics model and dynamic model.to facilitate the application of the control method,decoupling of its vertical and horizontal control model, according to the actual need on the vertical linear process control model. Considering the model uncertainty, upper and lower limits of model parameters are given vertical and horizontal control model after perturbation.Thirdly, for AUV vertical linear model, proposed a switching fuzzy variable structure AUV attitude control method based on the equivalent control and a switching fuzzy variable structure AUV attitude control method based on Index reaching law; for AUV horizontal nonlinear model, proposed a fuzzy self-tuning AUV track control method and a switching fuzzy variable structure AUV heading control method.At last, applied the control methods to the control model of AUV, simulation to achieve better control effect, verify its effectiveness and feasibility.