Research On Trajectory Tracking Control Of USV Based On Biological Inspiration

The track tracking of Unmanned Surface Vessel(USV)is an indispensable and important means to complete marine exploration,vessel fleet sailing,military reconnaissance and other missions.However,due to the under-actuation,non-linearity,high coupling and other characteristics of USV,as well as the influence of environmental interference and other factors,the trajectory tracking control of USV is more difficult.Based on the above reasons,this paper designs the controller based on the bio-inspired backstepping method and the backstepping sliding mode method.The problems in the design of USV trajectory tracking controller,such as large derivative calculation,input saturation and environmental interference,are dealt with and verified by simulation.The specific research work of this paper is shown as follows:1.The mathematical model of USV is established.Based on the idea of separation model modeling,the North East coordinate system and the hull coordinate system are established,and the six-degree-of-freedom mathematical model of USV is described.In order to design the controller conveniently,a 3-dof mathematical model of USV is established based on a series of assumptions.After that,the steady direct sail and steady turning sail simulation verification were carried out on the established USV model,which further proved that the dynamic performance and maneuverability of the established USV mathematical model could meet the requirements..It lays a foundation for the verification of the following trajectory tracking controller design.2.Completed the establishment of the bio-inspired model,and designed the trajectory tracking controller with the backstepping method.This paper introduces the basic principle and characteristics of the bio-inspired model,and establishes the bio-inspired model.Through the simulation,the function of the bio-inspired model in differential substitution and smoothing output signal is verified.In the process of designing USV trajectory tracking controller by backstepping method,this paper uses the biological inspired model replace the differential variables.which reduces the large number of derivative operations in the design process and simplifies the controller design process.And through the simulation of the linear and circular trajectory tracking path,it is verified that the designed controller can effectively track the setting trajectory.3.A USV backstepping sliding mode trajectory tracking controller based on bio-inspired model is established.In this paper,an exponentially convergent disturbance observer is designed to estimate the unknown environmental disturbance during actual navigation and compensate it on the controller.When designing the controller,the backstepping method was used to design the controller.The real-time position error and angle error were fed into the bioinspired model for processing,so that the error output signal was smooth and bounded,and the virtual desired longitudinal velocity and heading angular velocity were designed.After that,the sliding surface is brought into the design step of the backstepping method by using the backstepping and sliding mode method,and the differential term of the virtual speed is processed by using the bio-inspired model to stabilize the speed error,so as to obtain the control rate.Finally,through the simulation experiments,the algorithm in this chapter is compared with the traditional backstepping and sliding mode method,which proves that the algorithm in this paper can effectively avoid the occurrence of input saturation.