Ocean wave active compensation analysis of inverse kinematics for hybrid boarding system based on fuzzy algorithm

Abstract

In this paper, a method of solving inverse kinematics based on fuzzy algorithm for hybrid system is presented. This approach could compensate the wave disturbances when the hybrid mechanism is conducting a certain task, such as, transporting the repairmen into wind turbine platform. By deriving the Jacobian matrix of the hybrid mechanism, the relationship between the angular and linear velocities of variables in joint space and gangway's end-effector in task-space can be obtained. Thereafter, the numerical integral method is used to obtain the inverse kinematic solution. Structurally, the hybrid mechanism consists of a 6-DOFs Stewart parallel platform and a 3-DOFs gangway. Due to the kinematical redundant of the hybrid boarding system, its inverse kinematic solutions are not unique. Thus, a fuzzy strategy is put forward to plan the variable values reasonably. Moreover, it can satisfy the requirement of variable constraints. When conducting ocean wave compensation, specifically, the Stewart parallel platform is used to compensate the wave disturbance in roll direction. Moreover, it is efficient to compensate other disturbances by adjusting the joint angles of gangway. The effectiveness and the robustness of the proposed method is demonstrated using numerical simulation when the wave disturbance is added into the hybrid boarding system.