Experimental Research On 3D Printing Technology With Soft Materials For Soft Robotics

Soft robots are emerging hotspots and development frontiers of today's robotics.Various types of soft robots are designed and applied in many fields with the continuous development of robotics.Soft robots usually consist of materials that are easily deformed,such as fluids,gels,and functional polymers.These materials exhibit many of the same elastic and rheological properties as mollusk natural biological matter.It can maintain the initial running state when the robots are stretched and squeezed.It is important that these materials have certain compatibility with 3D printing technology.Traditional methods of taking shape of soft robots are mold casting mostly.They have gradually been replaced by faster and more reliable 3D printing technology.Soft robots are an important direction for the development of robotics.It has huge application prospects in many aspects,such as grasping objects,field exploration,and camouflage escape.3D printing technology has a unique advantage in manufacturing soft robots with complex external shapes and internal porous structures.It links tedious internal structural design with additive manufacturing technology.It is possible to create a series of soft robots with various driving methods and various materials.A series of DIW-type 3D printing platforms have been established by combining the current research status and the theory of Direct Ink Wrinting(DIW)type 3D printing manufacturing technology.The selection of silicone material for platform system is proposed.Carried out research on the printing process parameters of 3D printing of soft materials for soft robots and using the best combination of printing process parameters to conduct soft robot printing experimentsThe main discussions in this article are listed as follows:(1)Aiming at the problem of complex and backward 3D printing of soft materials in soft robots.This subject has studied the principle of 3D printing based on DIW and introduced the five basic components of building a platform.It has designed and built a series of 3D printing platforms made of silicone material capable of printing the body and driving structure of soft robots.Aiming at the diversity of DIW printers,three different 3D printers are designed and built,which provides greater flexibility for the design and method of 3D printable shapes.At the same time,the properties of various silicone materials were tested.DC737 was determined to be the best printing material suitable for DIW printing platforms.(2)The nozzle system is one of the key devices of the DIW 3D printing platform made of soft materials.Two nozzle flow models including straight nozzles and wedge nozzles were analyzed.The flow state analysis of the silicone material extruded in the nozzle was analyzed,including viscous fluid flow characteristics and a two-phase laminar fluid flow model.In the analysis of the material extrusion molding module,the force of the material in the extrusion nozzle was analyzed.And the establishment of the silicone material extrusion nozzle system model and the molding situation after extrusion were studied.The simulation of the extrusion nozzle system and the results were analyzed by the COMSOL Multiphysics analysis software.Including the analysis of different types of nozzle extrusion models,coupled models of materials and air.(3)The printing parameters of the silicone DIW printing process were optimized by experiments.Based on the 3D printing platform and one-component silicone material in this subject,it can achieve high-quality and efficient printing of solid or complex geometric structures.Perform single-wire printing,single-line wall printing,rectangular solid printing,bridge transition solid printing,and test stretch printing.Investigating the optimal parameter combination of driving extrusion pressure p,nozzle moving speed v0,layer height h,wire spacing c,bridging transition angle ζ and filling angle β.It lays the foundation for directly 3D printing soft robots with soft materials.(4)By analyzing the mechanical characteristics of the kinematics,a multi-balloon-driven soft robot is designed based on the creeping principle of the ruler and the size of the bionic soft robot is determined.A general pneumatic control platform was designed based on the pneumatic control principle of soft robot.Based on the built-in DIW-type 3D printing platform and the three selected materials,soft robots with different composition of printing materials are printed.The angle bending,linear creeping,failure pressure,and gravity comparison experiments were performed on these three soft robots respectively.The feasibility of this paper's 3D printing platform system with soft material could be beneficial to print soft robotics efficiently and accurately.