Research On Soft Robot Based On Minimum Energy Structure Of Dielectric Elastomer

Soft robots are mostly composed of polymers with high flexibility and biocompatibility,which can make up for the deficiencies of traditional rigid robots in areas such as human-robot interaction,intelligent bionic,unstructured environments.Dielectric Elastomer(DE)is an electroactive polymer material that can be deformed under voltage excitation,which is characterized by large deformation,fast response,high energy density and high conversion efficiency.It has a broad application prospects in the fields of soft robots,flexible sensors,biomedicine,energy harvest and controlled optics,which are the hotspots of current academic research.In this paper,a soft robot with high linearity and variable configuration is proposed according to dielectric elastomers minimum energy structure,and carried out the following studies from both theoretical modeling and experiments.1.Based on the theory of thermodynamics and continuum mechanics,the deformation mechanism of dielectric elastomer under electromechanical coupling is introduced;the equations of state of dielectric elastomer is derived using nominal and true quantities;the mechanical behaviors of dielectric elastomer in three deformation modes is studied;the intrinsic relationships of dielectric elastomer considering viscoelastic influence is given.2.Using the pure shear deformation characteristics of the dielectric elastomer,a new dielectric elastomer minimum energy structure actuator was designed;the control equations of the actuate under voltage stimulation were established by the Euder-Lagrange method,and the actuator was tested and analyzed through experiments.The results show that the actuation can reach 16.6 mm,and the blocking force up to 0.8 N under 6 kV voltage excitation,in addition,there is a good linear relationship between displacement and blocking force;at the same voltage,the greater transverse pre-stretch of elastomer material,the better actuate performance.3.Combining the one-way bearing with the dielectric elastomer minimum energy structure actuator,a soft robot with excellent performance is produced,the motion characteristics of the robot under different loading conditions were investigated by experiments.The research shows that the maximum crawling speed of the robot is 110 mm/s(about 2.2 body length/s)when driven by 50%duty cycle square wave;under a payload of 40 g(about 3.8 times robot's weight),the robot can still move steadily at a speed of 15 mm/s;by applying a bias voltage,the robot can be highly adaptable,that is,the robot can smoothly pass through a narrow channel whose height is only half of it.4.In this dissertation,we proposed the idea of combining triboelectric nanogenerators(TENG)and soft robots firstly,and the actuate control integration is preliminary confirmed by experiments,and the relationship between the freestanding TENG sliding speed and the motion characteristics of the soft robot was investigated.It is shown that the robot motion and TENG sliding speed are positively correlated.Moreover,regardless of whether the soft robot carries a payload or not,there is a good linear relationship between its motion and TENG sliding speed.