Research On The Maneuverability And Motion Control Of The Vertical Flat AUV

The full deep sea AUV is one of the hot issues in the field of underwater vehicles research.Due to the long floating and dive time,it need to reduce the vertical resistance.Therefore,the AUV can be designed flat body shape structure so as to decrease the welcoming area of the vertical plane.And then,the vertical resistance will be reduced.For the vertical flat AUV,it differs from cylindrical AUV because of its special shape of the structure.Taking it into account,its dynamic characteristics need to be considered.The thesis is based on it to conduct the research on the maneuverability and motion control problems of the vertical flat AUV.Firstly,the six degrees of freedom dynamic model of the vertical flat AUV is established.In order to facilitate research,it can be decoupled to three degrees of freedom dynamic models,including horizontal plane and vertical plane.In the horizontal plane,the stability of the horizontal plane motion is analyzed at first.Then it comes to the simulation of longitudinal speed and horizontal rotary motion.After that,the maneuverability performance of AUV horizontal motion is obtained.In the vertical plane,the first discussed problem is vertical stability analysis.And then it comes to the simulation of vertical speed and the space constant spiral motion.After that,the maneuverability performance of AUV vertical motion is obtained,too.The conclusion on maneuverability and control of the vertical flat AUV is acquired comparing to the cylindrical AUV.Finally,due to the research background of full deep sea,it is conducted of the research on the vertical flat AUV submerge without power.After that,the best submerge way can be predicted.Secondly,the fuzzy controller is designed combined with the motion characteristics of the vertical flat AUV.By using it,the simulation experiments of speed control,heading control and depth control are conducted.And comparing the results to the PID controller's,it is clear to get the advantages and disadvantages of the fuzzy controller.An improved adaptive fuzzy controller is designed against the shortcomings of fuzzy controller.According to it,the corresponding simulation experiments are conducted.And comparing to the fuzzy controller,it is proved to be more effective and precise.Finally,to go a step further,utilize the improved adaptive fuzzy controller to do the path following control experiments of the vertical flat AUV.The guidance method for obtaining a reference heading angle is based on the positional deviation and the heading deviation.To achieve the target path,the AUV's heading angle and coordinate should be changed all the time,so as to fulfill the path following control.There are simulation experiments to verify it,too.They are the path following control of straight line,quadrilateral and cosine curve.And the results show the actual path and the desired path in good agreement,proving that the improved adaptive fuzzy controller has a good performance in path following control.