Research On Path Planning And Control Of UUV Tracking The Mothership

In the implement of surface lifting recovery under the condition of harsh seas climate, it needs to increase the processing that the mothership guides UUV's navigation, in other words,UUV tracks the mothership. As a result, UUV will be guided to sheltered waters(such as port or the leewrd side of the island) for the underwater lifting recovery. Two technical problems are involved in this process inevitably: safe path planning without obstacles during UUV tracking the mothership and controling UUV sailing in the planned trajectory, which is the paper focused on for analysising and research.In order to plan the safe path without obstracles for the UUV tracking the mothership,this paper firstly describes the basic requirements for UUV's safe path planning, and verifies the effectiveness that based on the shortest space length trajectory as the performance through the theory. Then an order polynomial path planning curve function with variable parameters is established. In the condition of the boundary condition, the collision free condition and the detection range of the initial and termination, and according to the kinematic constraint of UUV and the limitation of measuring the working distance of communication equipment,finally solved the coefficients of the tracking polynomial equation group. Because of the existence of variable parameters in the curve function of the path planning, the obtained tracks will form a cluster of tracks. After that, through setting up the performance index of the shortest path length, then selected an optimal track which is the UUV tracking the mother ship from the cluster tracks. The improved method has a strong suitability by improved the applicable condition.Finally,contrapose the expect state information of path planning adopted Redundancy design, ensure that path planning can be executed when UUV cannot receive the expect state information wholly.To design the excellent performance of the three-dimensional trajectory tracking controller is the important technical prerequisite to ensure that the UUV successfully completed the mother ship tracking to reach the target recovery area. In view of the traditional backstepping recursive process which need step by step to calculat the virtual control quantity derivatives, which leads to the problem of the tedious process of computing. In this paper, a new method of backstepping design is proposed. Firstly,the improved backstepping method column write Lyapunov function derivative through the equivalent, and define new error variables ,and design a linear feedback stabilization function only including tracking error which is simplified the form of virtual control function. Then, by choosing appropriate gain parameters that eliminate some of the nonlinear terms in the iterative process of the derivative of Lyapunov function, and simplifies the process of the iterative algorithm; at the same time,it ensures that the derivative of Lyapunov function is negative. Finally, the stability of the controller which is designed by improved backstepping method is proved to be stable by using the Lyapunov stability. That is to say, the tracking error of UUV is convergent.At the end of the paper, using experimental simulation where is in the geographical information of a real sea area in the South China Sea,which simulation and verification of UUV tracking mother ship path planning and tracking control.This is the synthesis and development for the third chapter and the fourth chapter experiment. From an initial state to an expect state, it is extended to the geographical conditions in the real sea area. UUV continuous input of the new initial state and the termination of the state of the path planning and tracking control with the time coursing which is better to show the UUV tracking the movement of the mother ship. The result of the comprehensive experiment is fully proved the validity and practicability of the two core algorithm of path planning method based on UUV tracking of mother ship and tracking control method which is in the case of real sea distance.