DESIGN AND OPTIMIZATION OF 6-DOF PLATFORM TOP PLATE UNDER REALISTIC JOINT CONDITIONS

In this work, an FEA based methodology is proposed for the accurate prediction of stiffness properties of top plate of special application 6-DOF platform. The effect of joint contact conditions on the static stiffness and natural frequency of the top plate is analysed and compared with experimental results. Top plate is first designed using a simplified finite element model where the joint contact is considered to be rigid. The design failed to meet the actual operating conditions when tested experimentally. The design is revised using actual loading conditions and introducing realistic joint contact formulation. The results obtained are in close agreement with experimental data. Based on the developed methodology, a Multi-Objective Genetic Algorithm (MOGA) based optimization study has been carried out to reach an optimum design meeting the desired performance with a minimum possible weight. Both size and shape of the top plate has been optimized and weight reduction of 5.08 % has been achieved using the shape optimization. The performance parameters of final design of top plate differ by only 1.43 % for static stiffness and 0.44 % for modal response when compared with the experimental results.