The Research And Implementation Of The Upper Decision-making System For Autonomous Underwater Vehicle

The upper Decision-making system is the crucial technology for research of modern Autonomous Underwater Vehicle (AUV) and determines AUV's intelligence level in some extent. This paper aims to explore a reliable and efficient AUV upper Decision-making system which allows AUV to achieve autonomous navigation in complex underwater environment.Path planning and Decision-making control are crucial issues for the AUV's upper Decision-making system. Path planning is used to extract cost or approximately cost optimal paths form starting position to the end in complex and continuous environments. Decision-making control makes decisions for AUV's movement based on planned paths, and is capable of handling the uncertainty in environments and correction of path tracking errors. This paper focuses on these two key issues for the design of the upper Decision-making system. The main research work is as follows:Firstly, this paper introduces the research of path planning. Global path planning based on Fast Marching (FM) algorithm is used to extract cost optimal paths from complex underwater environments. Then according to a large scale static unknown or partially unknown environment, this paper proposes a new path planning method which dynamically divides the global environment and uses multiple local optimizations instead of one-time global optimization. And meanwhile, we design a Decision-making control system with reactive structure based on behavior. This system divides AUV's behavior into two classes-Rational Behavior set and Perceptual Behavior set. Furthermore, in order to avoid dynamic obstacles, in avoidance behavior module of Decision-making control system improved artificial potential field (APF) is used to implement secondary path planning in local environments, which can make up for the disadvantage that the simple path planning couldn't cope with dynamic environments. Finally, this paper designs a AUV's upper Decision-making system which integrates the advantage of path planning method based on FM and Decision-making control system with reactive structure based on behavior, and adopts modular method dividing Decision-making system into task management module, path planning module. Decision-making control module, localization and mapping module and so on. which is characterized by easy to implement and expand.And meanwhile, this paper first verifies the effectiveness of AUV's Decision-making system by MATLAB simulation, then uses C/C++ language to implement this system on Microsoft's VC++6.0 development platform. Programming running results show that the design of the AUV's upper Decision-making system is effective, and succeed in implementing AUV's autonomous navigation with complex environments.