Research On Dynamical Energy Saving Strategy On Long-range AUV

Long-range underwater vehicles also known as long-range AUVs,have extensive application prospects in chart mapping,marine environment detection,and some military aspects,and have huge economic and social benefits.With the continuous deepening of ocean exploration and development,the need for further improvement of long-range AUV endurance capability becomes more urgent.For various reasons,the long-range AUV surface is not completely symmetrical,and the resulting zero lift(moment)makes it impossible for the AUV to sail in an optimal attitude,resulting in increased resistance.A hybrid-driven long-range AUV equipped with a center-ofgravity adjustment mechanism and a buoyancy-adjusting mechanism,internally equipped with a weight and a variable volume oil bladder that can be moved forward and backward,using three actuators for depth and attitude adjustment,having a better depth,attitude control capabilities.Due to its over-driving in depth and trim control,through the reasonable cooperation of various actuators,the influence of zero lift(moment)on AUV can be overcome.However,due to the differences in the response rate and power consumption characteristics of each implementing agency,it is difficult to assign a total control force with a fixed weight.The zero-lift(moment)of AUV changes with the speed of navigation,and the navigation is easily concealed by other external disturbances and is difficult to recognize.This is particularly evident in near-surface navigation.In the near-surface navigation,the rudder requires highfrequency steering to maintain the depth and also consumes a lot of energy.Therefore,energysaving optimization of near-surface navigation is the difficulty of the AUV energy-saving navigation strategy.This article uses the above-mentioned hybrid-driven long-range AUV as an object to conduct near-surface navigation energy-saving optimization research.The difference in the response rate of the actuator and the problem of zero lift(moment)being difficult to discern.In this paper,zero lift(moment)is regarded as low-frequency interference,and a control distributor based on complementary filter concept is designed to decompose the depth error signal into two signals according to the rate of change.Under the premise of ensuring the smooth operation of the buoyancy and gravity center adjustment mechanism,The buoyancy and center-of-gravity adjustment mechanism overcomes the low-frequency interference during navigation and reduces the range of change of the rudder angle and pitch angle to achieve the purpose of reducing navigational resistance.Complementary filter control and distribution basically solves the problem of different response rates of the actuator and reduces the rudder angle variation during navigation.However,when the depth error signal frequency is in the transition band of the filter,the allocation weights of the actuators are similar and can be further optimized.In view of this situation,this paper comprehensively considers the current attitude of AUV and the current position of the implementing agency,establishes energy consumption indicators,and based on the concept of human-like intelligence,establishes dynamic allocation weights,and further optimizes the control allocation strategy.Aiming at the situation that AUV is subjected to high-frequency wave loading while navigating near the water surface,a new predictive control method is given.That is,dividing error signal into several periodic sine signal with zero mean value by the adaptive Hopf oscillator group.In the controller,some signals that do not affect the AUV navigation quality are actively ignored.Under the premise of guaranteeing the navigation depth,the steering speed is reduced.