Development And Technical Verification Of Unmanned Surface Vessel System With Dynamic Positioning Capability

Unmanned Surface Vehicleis(USV)is the innovation integration of intelligence,information and traditional ship technology,and it is the future development trend.However,the domestic USV is still in the early stage of technology development,and many key technologies have not completely broken through,especially the key technology of "Dynamic Positioning"."Dynamic positioning" is the foundation of many application fields,such as mobile refueling of USV,automatic berthing of USV,maritime rescue of USV and so on,which has important academic value and engineering significance.This paper designs and develops a dynamic positioning system based on the thrust allocation algorithm for the key technology of dynamic positioning in the USV system.The system includes the establishment of thrust allocation model.The thrust allocation problem is transformed into a non convex non linear constraint optimization problem through the establishment of objective function and constraint conditions.At the same time,a special objective function term is added to avoid singularity of the thrust allocation problem.In order to solve the problem of insufficient computing speed,the paper proposed an iterative solution method of local convex quadratic programming approximation with the help of MOSEK solver,which reduced the solution of non convex nonlinear constrained optimization problem to less than 1ms of computing time per sampling.In this paper,constraint conditions of four kinds of propeller structures are constructed,including thrust size constraint,thrust rate of change constraint,angle constraint and angle rate of change constraint.We have carried on the computer simulation,and added the white noise to simulate environment interference,analyzed the thrust distribution effect.In this paper,the physical simulation platform of the dynamic positioning USV was built,including the design and implementation of software and hardware platform.Through human-computer interface and joystick control,the model ship can simulate and demonstrate the dynamic positioning of multiple working conditions in the ocean engineering pool,which provides a complete experimental platform and scientific research foundation for the further research of the control of the dynamic positioning USV.The relationship between speed and thrust is measured by thrust measurement experiment.The "4-corner box" test experiment was carried out in the offshore engineering pool to verify the stability of the dynamic positioning function and the low-speed maneuverability,and the actual effect of the thrust distribution and controller was evaluated.