Research On The Preparation Method Of Electro Actuated Dielectric Elastomer Cylindrical Actuator

As one of the most influential new materials in the 21 st century,Dielectric Elastomer(DE),with its advantages of high energy density,light weight,good biocompatibility and fast deformation speed,promotes the rapid development of soft robots and innovatively achieves the reversible conversion of mechanical energy and electric energy.At present,many researchers have made various forms of actuators through structural design,mechanical simulation,material development and other aspects,which have shown great development prospects in aerospace,industrial production,medical treatment and other aspects.In this paper,VHB4910 film is selected as the dielectric elastomer material.Based on the working principle of the dielectric elastomer,a cylindrical driver is designed.The theoretical analysis,structural design,manufacturing and specific application are described and analyzed.(1)Based on the parameters of VHB4910 film material,the hyperelastic model--Yeoh model and Ogden model were used to build mathematical theoretical models for the electrodeformation process of the cylindrical actuator,respectively.The influences of pretension ratio,loading voltage and other factors on the driving performance(axial stress,electrodeformation capacity)of the actuator were analyzed.The axial stress of the cylindrical actuator is positively correlated with the loading voltage and pretensile ratio,while the electroinduced deformation of the actuator increases first and then decreases.Therefore,in order to keep the drive working properly,the driver should also have high efficiency driving performance,and the loading voltage and pretension ratio should be controlled in a reasonable range.For VHB4910,the optimal equibiaxial pretension ratio is about 3.(2)In order to explore the safe and reliable working space of cylindrical actuator,this paper,based on thermodynamic theory Helmholtz free energy function and Ogden model,carries out numerical analysis and solution for four failure modes of actuator during its working process:electromechanical instability,electric breakdown,tension instability and ultimate tensile fracture.The effective working space of the actuator is obtained,which provides a good theoretical support for the subsequent application of the actuator.When the pretension ratio is small,the main failure mode of the actuator is the loss of tension(S1=0).When the pretension ratio is large,the failure form is the breakdown of the material.(3)According to the working principle and the theoretical basis of the cylinder driver,the structure of the driver was designed,and the test platform was built,and the performance of the cylinder driver was tested on the output force,output displacement and fatigue life.Under the loading voltage of 4.2kV,the elongation strain of the cylindrical actuator designed in this paper can reach 15.2%,the maximum output push force is 2.76N,the maximum output return force is 3.07N,and the critical breakdown voltage is 4.5kV.Moreover,with the increase of the applied voltage cycle times,the driving performance of the actuator tends to decline.According to the designed cylindrical actuator,a three claw grabbing mechanism is designed.The mechanical analysis and structural design of its degree of freedom,rotation angle and output force are carried out.The 3D printing equipment was used to complete the production of each component of grasping mechanism,and the assembly of grasping mechanism was completed and the grasping performance test was completed.(4)The cylinder drives the leakage in the working process of the equivalent circuit model is established,the parameters in the model measurement method is proposed,and the leakage current is measured using the method of experimental measurement,found in low voltage,the leakage phenomenon is not obvious,when increasing the load voltage,leakage phenomenon is obvious.