Research On Pitch And Depth Control Of AUV Diving Under Wave Disturbance

Since the beginning of this century,man has known the importance of the ocean and explored it.The better the subsea equipment,the better the exploitation and utilization of ocean resources,these technologies are becoming more and more attractive.Underwater robot is an effective deep-sea probe has been developed as an important method of ocean exploration,the article uses "NPS AUV Ⅱ" type underwater robot as a model to explore,in the process of underwater robot movement,Focus on underwater robot in the diving movement to a given depth of the work and may cause greater pitching Angle along with all the key to explore the change rule,the underwater robot can descend quickly smooth water depth as the ultimate goal of a given work,to explore underwater robot in diving depth and pitch Angle of the movement of reasonable control method.Firstly,the functions,structures and parameters related to the "NPS AUV Ⅱ" underwater vehicle are introduced.The six-dOF nonlinear motion equation model of the underwater vehicle is constructed by using the "NPS AUV Ⅱ" underwater vehicle as a model.Then,in order to simplify the design of the control system and the study of the simplified system model,The six degrees of freedom nonlinear motion equation of underwater vehicle should be linearized.The lift model of the horizontal rudder is introduced,which can control the underwater robot by using the active longitudinal flapping of the water surface to produce appropriate righting moment.Then introduce some basic theory and formula of random sea waves,the waves is deduced step by step the first-order wave disturbing force and moment calculation formula,in the MATLAB program,are simulated in different sea condition,the first order wave disturbing force and moment of the waves simulation research,analysis of random waves descend to underwater robot vertical disturbances.Then,the second order wave interference force and moment calculation formula of wave is derived step by step,and the program is written in MATLAB to simulate the second order wave interference force and moment of wave under different sea conditions,and analyze the influence of random wave on vertical disturbance of underwater robot when diving.Secondly,the sliding mode variable structure control principle is applied to design the controller and the chattering phenomenon is restrained by the approach rate method.Combined with the analysis of the working characteristics and 6-dOF motion model of the underwater robot in the process of diving,the depth controller of the underwater robot is designed by choosing the horizontal rudder of the underwater robot as the depth control device.Combined with the analysis of the working characteristics and 6-dOF motion model,the pitch Angle controller is designed by choosing the horizontal rudder of the auV as the pitch Angle control device.Finally,the program is written in MATLAB,and the simulation is carried out under different sea conditions.The results show that the depth can reach the specified depth,the pitch Angle is greatly reduced,and basically remains stable.Verify the effectiveness of depth controller and pitch Angle controller.Finally,due to the limited energy carried by the underwater robot,energy optimization should be considered.According to relevant references,performance indicators based on energy are designed,and relevant parameters are optimized by particle swarm optimization algorithm,and simulation analysis is carried out.Simulation results show that the energy consumption can be maintained at a low level,which proves the feasibility of the parameter optimization process.