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Autonomous planning is an important ability for autonomous underwater vehicle (AUV), which is a crucial factor for ensuring and guiding AUV to long-term navigate and accomplish its mission in large range and unstructured oceanic area. In general, the technology of autonomous planning could be sorted into global path planning and local path planning. In this paper, the former is solved by adopting adaptive genetic algorithm (AGA), which aimed at searching an optimized path according to some optimization criteria in a known and certain environment. This algorithm also can be adapted and applied to dynamic plan a collision-free path based on sonar and real-time navigate AUV in unknown and uncertain environment. By analyzing the motion security of AUV, two kinds of regions which are defined as forbidden zone and potential collision zone, and some safety motion criterions are also proposed for AUV. All of above researches are simulated in a semi-physical simulation platform, and the results show that the autonomous planning algorithms are valid, efficient and reliable. The adaptive abilities and autonomy of AUV can make it possible to long-term navigate in ocean and succeed in its mission. [ABSTRACT FROM AUTHOR]

Misturiing refers to the variations of blades properties due to procession and wear etc. Though these variations is small, they can confine the vibration energy in a few blades, and increase the resonant response of those blades. Therefore, dry friction dampers are often used to reduce the vibration of blades. In order to investigate the effects of mistuning and the performance of dry friction dampers, it is necessary to develop an efficient numerical method to predict the resonant features of the bladed disks with dry friction dampers. We propose an efficient multi-harmonic (MH) method which is based on the harmonic balance method. The formulation of the method can take the advantage of fast Fourier transformation (FFT) which can facilitate the analysis efficiency significantly. The iterative Newton-Raphson procedure are used to solve the nonlinear vibration equation. The MH method has been used in a mass-string model of bladed disk, and validated by numerical integration method. The analysis of forced response features is performed by the MH method for both tuned and mistuned systems with various coupling strength, viscous damping, dry friction damping and blade stiffness mistuning etc. The results indicate that the MH method can efficiently predict the resonant response of the bladed disks with nonlinear dry friction damping. It is found that, for the weakly coupled bladed disk with nonlinear blade-to-blade dry friction damping, mistuning can reduce resonant amplitudes of the system significantly when dry friction and viscous damping are all smaller. This is not common for mistuning effects. In other situation, Mistuning can increase the resonant amplitudes, broaden the resonant frequency region, and produce multiple resonant peaks. [ABSTRACT FROM AUTHOR]