Research On Underwater Vehicle Controller Based On Single Input Fuzzy Control

Unmanned underwater vehicle(UUV)is a kind of submarine like robot without pilot,which is used for underwater tasks,such as search and rescue,measurement,monitoring,inspection,repair and maintenance.During the operation of the underwater vehicle,its trajectory will be highly nonlinear.In addition,the dynamic performance of the vehicle can also change significantly with the change of surrounding environment and external interference(such as wind speed and current).These factors make it difficult for us to accurately model the space motion of underwater vehicle.Fuzzy control has strong robustness and can adapt to the uncertainty of fluid dynamics.It can not only control a variety of linear systems,but also has more obvious advantages than traditional control in nonlinear system control.At the same time,the nonlinear performance of fuzzy control system makes it have strong resistance to external interference.Therefore,fuzzy control is an ideal control method for underwater vehicle.The performance of fuzzy controller depends on its reasoning rules to a great extent.Generally,the more rules are applied to the fuzzy controller,the higher the accuracy of the control action is.However,with the increase of control rules,the calculation amount and complexity of fuzzy control will also increase,and the performance requirements of hardware system will also increase.Therefore,on the basis of ensuring the control effect as much as possible,it is necessary to simplify the calculation amount of fuzzy rules.Based on the above factors,the design of single input fuzzy controller for underwater vehicle is proposed in this paper.Firstly,combined with the characteristics of the underwater vehicle and the advantages of fuzzy control,the fuzzy control is selected as the control method of the underwater vehicle,and the theoretical derivation of the kinematics and dynamics equations of the underwater vehicle is carried out based on the force conditions and interference factors of the underwater vehicle.Secondly,the emphasis of this paper is to simplify the classical double input fuzzy control rules into single input fuzzy control rules.The simplified rules make the fuzzy control of underwater vehicles easier to achieve.Through the detailed analysis of the structure and implementation process of the fuzzy controller,the classical double input fuzzy control rule table is simplified in one dimension.Through reasoning and experiment,it is concluded that the input of fuzzy control is transformed from two(more)state variables into single variable basic conversion relationship.Then,the single input fuzzy control of underwater vehicle is compared with the classical double input fuzzy controller through simulation.The results show that the simplified single input fuzzy controller has good control effect,but its reasoning rules are greatly reduced and the simulation time is less.Finally,the fuzzy PID control is studied.The simplified fuzzy control rules are applied to the fuzzy PID control rules.The classical fuzzy PID control rules are obviously more than the simplified one-dimensional input PID fuzzy control rules,but the control effect is not better than the single input fuzzy control with few control rules.The simulation results show that the control rules of double input fuzzy PID control are redundant and can be simplified...