Design Optimization of Rigid Body Mechanism Topology

Despite modern computer based design tools, the development process of new mechanisms is still based on the engineer’s experience, intuition and ingenuity. The goal of this work is to find a combination of linkage topology and joint types that represent the most suitable mechanism layout for a particular task. Optimization techniques are hardly used for this design problem except for the task of dimensional synthesis of a given mechanism type. This study presents and compares two different approaches to topology or type optimization of planar rigid body mechanisms that can be used to improve the overall design process. The first approach is based on a truss-like ground structure that represents an over-determined system of rigid bars where the most appropriate topology can be extracted from this ground structure by means of gradient based optimization algorithms. In the second approach, we use a genetic algorithm for the intrinsically combinatorial problem of topology synthesis. We explain both approaches and show their capabilities, their advantages and drawbacks.