Research On The Dynamic Modeling And Energy-saving Control For A Water-jet Hybrid Glider

The Water-Jet Hybrid Glider(WJHG)was designed to meet the observation needs of long-term deep-sea marine hydrological elements observation with multiple operation modes.Via months of saw-tooth glide observation,masses of high resolution hydrological data can be sampled and occasional phenomenon may be captured.In level flight mode,the thermocline can be sampled in dense.Current glider dynamic models are insufficient to satisfy the requirements of WJHG's performance evaluation and control law research,because their accuracy is needed to be improved and they assumed a constant environment.Hence,by building an accurate dynamic model for WJHG and simulating with it,carrying on sufficient performance evaluation and energy-saving control for WJHG becomes the key to improve the duration of WJHG and explore water-jet level flight motion.The main contents in this paper are summarized below:Basing on Momentum theorem,we derivatived a 6-DOF dynamic model within marine environment,which laid a good foundation for WJHG performance evaluation and low-power control research.Meanwhile,basing on the model,a simulation software for WJHG was developed and provided a research method for subsequent chapters.Basing on WJHG's dynamic model,by analytic solution and numerical simulation,we studied the performance evaluation method for glide motion and propulsion motion.The glide motion performance includes lift/drag ratio,glide velocity,maneuverability and stability,and the propulsion performance includes propulsion velocity and stability.After evaluating WJHG's performance,we concluded that although the glide velocity of hydrodynamic shape in 2015 was a little lower than that in 2014,the shape in 2015 had higher lift/drag ratio,higher hydrodynamic efficiency and is more stable with disturbance or at sea.Basing on this,we researched on the maneuverability varying with ballast,roll angle,pitch angle,horizontal and vertical wings for WJHG for the shape in 2015 and obtained the main factors effecting on maneuverability radius.Besides,we predicted the propulsion velocity and studied on the level flight stability varying with propulsion velocity,buoyancy and wings configuration.Those work could guide the experiment of level fight for WJHG theoretically.By using the self-built simulation software for WJHG,basing on the energy-saving idea of reducing the frequency of actuator action and shortening the correcting time,we researched on the energy-saving pitch control algorithm according to steady glide equation and the energy-saving sectional head control algorithm tuned by heading rate.In addition,in order to avoid bottoming,we studied the over-depth control algorithm basing on pitch characters.Through a series of lake and sea tests,we carried out the steady pitch law test,the stability test of WJHG's pitch interfered by uneven sea water,manoeuvrablity test and propulsion velocity test,and the pitch control algorithm,head control algorithm and over-depth control strategy.Those test draw a conclusion that the theoretical results were consistent with the experiment results and the dynamic model for WJHG was accurate.