Research On AUV Roll Control

Life originated in the ocean,and human beings reproduced on the earth.The ocean contains abundant renewable resources,biological resources and mineral resources.AUV(Autonomous Underwater Vehicle)is widely used in military and civilian fields due to its good maneuverability and strong concealment,and is an important exploration tool for ocean development and research.For autonomous underwater vehicles,the requirements for stability are higher than those for maneuverability.This paper mainly studies the roll control of autonomous underwater vehicle,so as to improve the stability of autonomous underwater vehicle and improve the navigation performance of autonomous underwater vehicle.First of all,this paper analyzes the force of a new type of X-type four-propeller AUV when the four-propellers act differently,and establishes a coordinate system to describe the geometrical position of a single propeller.The dynamic equation of the propeller is derived from the force and moment equations such as propeller pulling force and pulling moment,propeller anti-torque moment,propeller gyro moment,etc.,and then the dynamic equation of the four-propeller is obtained.AUV power cabin model is established,and the model is simplified to facilitate subsequent use.After that,the motion control strategy of AUV was studied.The influence of different parameters of each link of the PID controller on the stability of the system and the roll effect of different propeller speeds are analyzed.A single roll variable mathematical model is established,the roll angle transfer function of the AUV carrier is calculated,the PID control simulation of the AUV carrier roll angle is completed,and the Kp,Ki,Kd parameter values are adjusted to make the output reach a stable state.Set different roll initial values to get the control effect under different initial values.Finally,it is concluded that the AUV roll can be effectively controlled within two cycles by adding PID roll control,and the time to reach the stable state is greatly shortened to 1.5s.Finally,because the values of the three parameters of the conventional PID controller are fixed,once the external environment or the working state of the system changes,the control effect will be greatly reduced.Therefore,an adaptive fuzzy control optimization system was added on the basis of the original PID to automatically adjust the three parameters.In order to verify its effect,an adaptive fuzzy PID controller and a simulation model were established,and the optimization effect was verified by analyzing the simulation results.This model and the previous conventional PID simulation model are connected to the same oscilloscope,and different initial values are set.By analyzing the simulation results,it is concluded that no matter how big the initial deviation Angle is,the PID controller with adaptive fuzzy control is better than the original PID controller.Under the same conditions,the time for the adaptive fuzzy PID controller to reach stability is reduced from 1.5s to 1s,the amplitude is 27%,and the oscillation period is reduced from 2.5 times to 1 time.The control effect has been significantly improved.