Design And Analysis Of Bistable Actuators Based On Dielectric Elastomer

Dielectric elastomer is regarded as one of the most promising candidates for artificial muscle due to its inherent characteristics of flexibility,large strain,high energy density,and fast response of the material,which has promising application prospects on the field of soft robotics and aerospace.In order to expand the lifespan and improve the output speed of dielectric elastomer actuators,this dissertation has put forward design methods and parameter optimization methods for translational bistable actuator and rotational bistable actuator based on DE.A pure shear test has been conducted through analytical simulation based on equilibrium thermodynamic framework and non-equilibrium thermodynamic framework and the impact of different material parameters has been analysed.Experiments have also been conducted on circular DEA to analyse the viscoelasticity of VHB4910 and its influences on the actuation performance of the actuators.Constant voltage with 500 s actuation time and sawtooth actuation signals have bean used to actuate the circular actuator and the analytical model have good consistency with the experimental result.Chained beam-constrained-model has been utilized to analyse the deformation of bistable beam in this dissertation.After analysing the deformation path of pre-compressed beam,a compact linear bistable actuator comprise of pre-compressed cross beam and conical DEA has been put forward.The analytical models of the beam and conical DEA have been established separately.Finite element analyse(FEA)and experiments have been conducted to validate the analytical model of the pre-compressed beam,while the material parameters of conical DEA have also been identified through experimental data.Based on the principle of force equilibrium,the working principle of translational bistable DEA and parameters optimization method have been discussed in detailed.Prototypes have been fabricated to verify the effectiveness of the design method and parameter optimization method.Besides,a compact rotational bistable actuator based on pre-compressed pinned-fixedclamped beam and rotational conical DEA has also been put forward.The analytical models of the beam and rotational conical DEA have been established separately.FEA and experiments have been conducted to validate the analytical model of the pre-compressed beam,while the material parameters of conical DEA have also been identified through experimental data.Based on the principle of torque equilibrium,the working principle of rotation bistable DEA and parameters optimization method have been discussed in detailed.Prototypes have been fabricated to verify the effectiveness of the design method and parameter optimization method.Taking translational bistable actuator as an example,a dynamic model has been established to analyse snap-through process,considering the viscoelasticity of DE material and damping effect.