Optimum Design Of 3-RRS Parallel Robot Based On MDO Theory

Modern mechanical product becomes increasingly complex, competitions among producers become more fury and rigorous, the demands for comprehensive properties of products get much higher. Traditional mechanical product design follows a serial way, Each discipline is always designed sequentially and separately. Due to such a lack of consideration of the relationship between the interdisciplinary interaction and the overall system performance throughout the mechanism design cycle, sequential design will not get the global optimal decision and also have multiple iterative or reworked, greatly lengthened the design cycle. Under this situation, in order to obtain a mechanism which has optimum comprehensive properties, the Multidisciplinary Design Optimization (MDO) theory has to be employed.The MDO has been widely discussed and used in aerospace and aeronautical industries and resulted in more reliable and better products. In MDO, the designer concurrently considers the interactions and coupling effects among different subsystem, so it is inclined to lead to a global optimal design results which must simultaneously meet the requirements of disciplines involved in.MDO is seldom used in the design of mechanisms. The motivation for this research is the investigation of current MDO algorithms and application of the MDO method to the design of complex mechanisms. The main improvement work includes:(1)The mathematical model of MDO was introduced. With Analysis on the idea and characteristics of MDO, MDO theory was combined with mechanism system design. Taking a typical four-bar linkage as an example, the application process of MDO technology in mechanism system design.(2)With further study on Collaborative Optimization (CO) algorithm, the computational complexity met in practical application was analyzed and the improvement measures were summarized. Computation example is used to test the improved CO algorithm, the results show that the improvement measures is effective.(3)The pose movement characteristics of 3-RRS parallel robot were analyzed. A hierarchically iterative search strategy is put forward to calculate the global condition index of mechanism. It avoids the complicated integral process of volume of workspace and easy to obtain the boundary surfaces of workspace.The computational cost is saved. This method is also suitable for the calculation of workspace of other types parallel robot.(4)MD0 theory was applied in the design problem of 3-RRS parallel robot. The pose movement characteristics of 3-RRS Parallel Robot were studied. With establishment of the MDO model of 3-RRS Parallel Robot, the multidisciplinary systems were design and calculation by using Kriging-CO algorithm.