The structure design and kinematics analysis of the manipulator for the upper port remote maintenance in DEMO

As part of the upper port remote maintenance in DEMO, the design of seven degrees of freedom (DOFs) redundant manipulator with a ceiling-mounted configuration was presented in this work. The proposed manipulator is capable of flexibly maneuvering around the big manipulator, extracting the stop elements, and placing them into a basket. It can also fold itself to create more space for the operation of the big manipulator. The kinematic model of the redundant manipulator was established based on the application of the Modified Denavit-Hartenberg (MDH) method, and an unconstrained optimization equation was formulated using quaternions. To solve this equation, an improved artificial bee colony (IABC) algorithm was developed by enhancing the local search capability of the employed bees and improving the search efficiency of the observation bees. The feasibility of the structural design and the IABC algorithm was verified by carrying out trajectory planning simulations of the manipulator. The design of the 7 DOFs manipulator and the corresponding offline inverse kinematics algorithm provide valuable references for the maintenance work in the upper port remote maintenance of the DEMO.