Research On The Cable-driven Parallel Salvage System On Catamaran

In recent years,with the rapid development of the marine transportation and the exploitation of the seabed resources,China's production activities in remote and offshore areas have become increasingly frequent,and the frequency of marine accidents has also increased.Manual salvage is currently the main method of sea rescue on the rescue boat.It is difficult to implement under harsh sea conditions,and the life safety of the crew on the boat cannot be guaranteed.The new marine rescue boat developed by this project is expected to solve this problem.The rescue boat learns from the design draws on the wave-adaptive catamaran with a special structure,which can withstand strong winds and waves and has a strong wave resistance.It is equipped with a redundant constrained cable-drive parallel mechanism as a marine salvage device to achieve automatic salvage.In order to achieve a good cooperation between the two,the structure and application environment of the catamaran should be fully considered,and the structure design and control of the cable-drive parallel mechanism should be studied.This is of great significance to the actual construction and operation of the rescue boat.The thesis firstly aimed at the construction of the base platform of the cable-driven parallel salvage mechanism,and established a complete mechanism inverse kinematics model with movable base position and a mechanism dynamics model to separate the motion interference of boat.Under the limitation of cable tension output,analyze the mechanism's ability to balance the external wrench,and then obtain the wrench-feasible verification conditions,the discrete method is used to solve the wrench-feasible workspace of the cable-drive parallel mechanism.The relationship between the mobile platform structure and the workspace is studied,the geometrical dimensions of the platform is optimized by particle swarm optimization to maximize the wrench-feasible workspace of the mechanism.The stiffness matrix of the cable-drive parallel mechanism is analyzed,the relationship between the stiffness matrix and the stability of the mechanism is studied,the applicable conditions of the analytical cable tension distribution method are obtained from the stability point of view,and the cable tension distribution optimization method is proposed to achieve the stiffness enhancement or adjustment of the cable-drive parallel mechanism.Finally,this paper studies the motion control method of the redundant constrained cable-drive parallel mechanism,which realizes the posture control of the mobile platform and the coordination of the internal forces between the cables in the hinge point space.From the perspective of practical engineering application,based on the motor position servo system,the feedforward control of cable internal force and the feedback control of cable tension are proposed.According to the characteristics of nonlinear and strong coupling of the parallel mechanism of cable-drive,the tension control of the parallel mechanism of cable-drive is proposed.The trajectory tracking and tension tracking of each control method under static and moving boats are compared.In order to achieve efficient salvage under sea conditions,a wave compensation algorithm is added to the controller,which effectively isolates the boat motion from the mobile platform's position and attitude interference.Based on Simulink and Adams co-simulation,the above control methods are simulated and verified,and their effectiveness is proved.