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In this paper, we mainly study the output feedback control problem of stochastic nonlinear system based on loose growth conditions and applies the research results to the electric vehicle control system of underwater oil and gas pipelines, which can improve the speed and stability of the equipment system. Firstly, the concept of randomness is introduced to study the tracking control problem of the system, which meet the more general polynomial function growth conditions. A combination of static and dynamic output feedback practices is proposed. The tracking controller makes all the states of the system, which meet boundedness and ensures that the tracking error of the system converges to a small neighborhood of zero. Secondly, the system is extended to the parameter uncertain system, the controller with complete dynamic gain is constructed by proving the boundedness of the system state and gain. Furtherly, the nonlinear term of the system satisfies the more relaxed power growth condition, combined with the inverse method to construct a set of Lyapunov functions and obtain the controller to ensure that the system is asymptotically probabilistic stability in the global scope. Finally, through the ocean library in the Simulation X software, the controller design results are imported into the underwater electro-hydraulic actuator model to verify the effectiveness.

The paper is concerned with station keeping control problem via backstepping for an autonomous underwater vehicle (AUV) systems with nonlinear continuous function. This paper is the first time to using backstepping control method for stochastic nonlinear systems. Under nonlinear growth conditions, when the AUV motion affected the driving force, resistance of ocean and the force generated by current the difficulty arising from the underwater robot system output feedback makes the station keeping problems challenging and forward-looking. There exist two problems to research the fast response time and good station keeping, respectively. There a new control method is proposed for the first time to construct a backstepping stabilizing controller. In this paper, a concept of randomness to study the station keeping control problem of output feedback of stochastic nonlinear systems, remove the original harsher growth conditions, make it meet the more general function growth conditions. In order to deal with the station error of system converges to arbitrarily small domains. Under all the states of the system meet boundedness, a coordinate transformation is proposed. A useful technical theorem is proposed in the stability analysis to show that combined with the backstepping method to cleverly construct a set of Lyapunov functions, and obtain the output controller to ensure that the system is asymptotically probabilistic in the global scope. Finally, through the ocean library in the Simulation X simulation software and the Hardware-in-the-loop simulation, the controller design results are imported into the AUV actuator model to verify the effectiveness of the controller design.