| The development of 3D printing technology has opened up the possibility of manufacturing soft robots with complex functions and structures,making up for the shortcomings of traditional manufacturing processes in the manufacture of complex structures.The materials that form the main part of soft robots include polymers,gels and other soft materials,of which silicone material is one of the most used soft materials,with the advantages of high elasticity,high stability,high responsiveness and excellent biocompatibility,which is the ideal material for manufacturing soft robots.Therefore,in order to realise the design and construction of complex internal cavity structures for soft robots,research on silicone extrusion-based printing processes for soft robots has been carried out,and the main research in this thesis is as follows:Firstly,the printing hardware and software used for the experiments are described,as well as the preparation and characterisation of the silicone materials used,based on silicone extrusion printing.The 3D printing platform,printhead,and printer control and trajectory planning software are described.The cross-linking principle and preparation method of the silicone ink are summarised,the material properties are characterised,the configuration rules are summarised through the characterisation results,and the silicone material is verified to have the material properties required to satisfy the main part of the soft robot.Secondly,to address the problem that low viscosity silicone inks cannot build cantilevered complex hollow structures,the effect of silica nanoparticles at different mass fractions on the rheological properties of the ink was investigated,and a model for the step effect of cantilevered structures was established and analysed.Subsequently,this was followed by a series of parameter optimisation experiments based on extruded high quality,high precision printing on silicone material.Experiments were carried out with monofilament extrusion,monofilament circular printing and monofilament cylindrical cavity printing in a linear-faceted logic.The optimum combination of nozzle flow rate,nozzle movement speed,pre-extrusion volume and layering thickness was determined from the results of the forming effect and accuracy.Mechanical property test specimens were printed,and the printed specimens were characterised for mechanical properties and forming accuracy respectively,and the results showed that the specimens had good mechanical properties as well as high forming accuracy.Finally,two cardiac in vitro simulation soft robots were designed based on the heart structure and pumping method.The deformation of the robots with different size parameters was analysed by finite element simulation,the size parameters were determined,the best combination of printing parameters was used for printing,pneumatic experiments were carried out on the assembled robots,and the driving performance of the two robots was analysed based on the experimental results and compared with the performance of the mouse heart muscle The results show that the heart is an in vitro simulation of the heart.The results show that the cardiac in vitro simulation soft robot has a driving performance close to that of the mouse myocardium,and also validate the feasibility of the silicone extrusion printing process for the construction of soft robots with complex structures. |
