Dynamic model of four degree of freedom rope-driven rigid-flexible hybrid wave compensation device

Abstract

In the process of replenishment at sea, in order to ensure the safety of workers and cargo on the deck, collisions between the cargo and the deck or cargo should be at least reduced if not avoided. Considering the actual situation of the marine environment, a fourdegree- of-freedom rope-driven rigid-flexible hybrid wave compensation mechanism for offshore hoisting equipment is proposed. First, based on the screw theory, the feasibility of a wave compensation mechanism was verified, and the experimental device of the wave compensation mechanism was designed. Then, a positional forward/reverse solution model of the wave compensation mechanism was established based on the algebraic method. Then, the kinematics model of the wave compensation mechanism was derived and the system dynamics model of the wave compensation mechanism was established based on Newton-Eulerian method. The simulation software was used to verify the derived mathematical model. It was found that the positional positive/negative solution error of the wave compensation mechanism was of the order of 10-5 mm; the MATLAB numerical simulation results and the Adams virtual prototype results of the kinematics and dynamics models were basically consistent. The maximum error was 2.4 % of the theoretical value, which is an acceptable range. The correctness of the derived kinematics and dynamics model was verified. The research results provide a theoretical basis for further performance analysis and motion control of the wave compensation mechanism.