Actuation Performance Of Flexible Joint Based On Dielectric Elastomer

As the core component of actuation,the flexible joint of soft robot should have high transmission performance and high output performance.The dielectric elastomer material known as "artificial muscle" can produce large deformation under the action of external electric field,and realize the transformation between electric field energy and mechanical energy.The joint actuator designed based on the dielectric elastomer material has light weight and quick response,high electromechanical conversion rate and good environmental adaptability,which meets the needs of all aspects of making flexible joint actuators.Therefore,this paper proposes a flexible joint actuator based on dielectric elastomer material design,and conducts electromechanical analysis on the dielectric elastomer material.At the same time,design,manufacture,analyze,model,simulate and experimentally test flexible joint actuators.Firstly,based on the thermo-mechanical coupling equation of state,this paper analyzes the mechanical properties of dielectric elastomer materials.Analyze and compare the difference between the performances of dielectric elastomer materials in terms of the performance of the two super-elastic models Neo-Hookean and Gent.Through the calculation of dimensionless plane uniaxial stretching and electrostatic loading,the results show that the stress of the Gent model increases rapidly when the tensile limit constant is approached,and the material hardens.Uniaxial tensile and dielectric constant tests were performed on the dielectric elastomer materials,and the material constants were fitted and solved to provide parameters for further analysis and modeling of the actuator.Secondly,based on the deformation mechanism of the dielectric elastomer,this paper designs a three-stage flexible joint actuator with the advantages of bidirectional active deformation.And the energy method was used to construct an analysis model of a single bending angle.Calculate the partial derivative of the total energy of the system to the bending angle through MATLAB,the structural parameters(thickness,bending length)of the flexible frame,and the pre-stretch rate of the dielectric elastomer film The law of influence on the bending angle.The analysis results show that when the pre-stretch rate is constant,the bending angle increases with the decrease of the thickness of the flexible frame(or the increase of the bending length),and on this basis,the dimensional parameters of the flexible frame are determined.At the same time,through experimental tests,the bending angle changes of the joint actuators under different electrode electrification combinations are compared to achieve a two-way active deformation effect.Finally,according to the designed flexible joint actuator and 3D printing technology,a gripping mechanism was designed and manufactured.The dynamic equation of the local bending angle is fitted by the method of equivalent calibration.At the same time,the approximate dynamic model of the flexible joint actuator is established by using the tension and compression spring and the torsion spring,and the simulation is carried out using ADAMS software to simulate the deformation state of the gripping mechanism under the dynamic rigidity change of the dielectric elastomer material.By designing and building a three-way electrostatic high-voltage control system,the prototype of the gripping mechanism was energized to realize the multi-pose movement of the gripping mechanism.