Integrated Layout Design Of Compliant Mechanisms And Actuators Using Explicit Topology Optimization Method

Compliant mechanisms have been widely used in the fields of microelectromechanical sys-tems,biomedicine,precision positioning and manipulation due to their high precision,friction-lessness and ease of miniaturisation,and have become an important branch in mechanisms.Topology optimization as a design method for compliant mechanisms has become one of the hot research topics,but so far,topology optimization methods have mostly focused on implicit methods,while explicit methods containing more geometric information have not been studied in depth.Based on the above background,this dissertation uses the explicit topology optimiza-tion method as a tool to a tool to study the theory and methodology of the integrated design of compliant mechanisms and actuators.The main research work is as follows:(1)Aiming at the problem of geometric interpolation errors in the representation of mov-ing morphable components in explicit topology optimization methods,a topology description model based on the projective transformation is presented.The cause of the component bound-ary offset phenomenon is revealed,and a hierarchical feature construction method is used to decompose the component into a series of implicit planes,eliminating interpolation errors in the geometric representation of components.The proposed method is combined with the extended finite element method to achieve detailed reconstruction of the structural boundaries inside the element,which effectively improves the consistency of the geometric model and the analysis model.(2)To address the minimum length scale constraint design problem in the explicit topol-ogy optimisation method of compliant mechanisms,an effective connection status(ECS)control model based on the virtual component skeleton(VCS)is proposed.The method uses the virtual component skeleton to extract the morphological characteristics of the moving morphable com-ponents and describe the relative positions between the components.Then,the evolution of the smallest cross section in the component overlap model is analyzed,and a minimum length scale control method based on the effective connection state is established.The proposed method effectively avoids the influence of component profile details and achieves precise control of the minimum scale of compliant mechanisms.(3)Based on the component topology description model using the projective transformation and introducing the parametric level set method,an explicit and implicit hybrid multi-component system topology description model is given,and a integrated topology optimization method of the compliant mechanisms and actuators is developed.The approximate solution of the dis-placement field near a discontinuous intersection of materials under force-electric coupling is investigated,in combination with the extended finite element method.The manufacturability of the designed mechanism is improved by imposing global geometric constraints on the ex-plicit and implicit topological description functions and considering the rigid-flexible coupling characteristics at the output ports.(4)Based on the integrated topology optimization method of the compliant mechanisms and actuators,a piezo-driven microgripper for micro-assembly is developed.A two-stage con-figuration design strategy is given,in which the first stage is a topological optimized microgrip-per and the second stage is a replaceable jaw end that adapts to different tiny parts.A scheme for connecting the jaws and the body of the microgripper is proposed.The feasibility of the proposed method is verified using finite element simulations and experiments.The research work in this dissertation provides a new method for the integrated topology optimization design of the compliant mechanisms and the actuators,promotes the further im-provement of the design theory of the compliant mechanisms and provides a new idea for the application of the compliant mechanisms in the field of micro-assembly.