| The dielectric electro-active polymer(EAP) has demonstrated large deformation, fast response, high energy density when under the action of the electric field. It has a good biological characteristics. The dynamic model of the dielectric EAP flexible unit is studied, which would lay the theoretical foundation for its application in the filed of bionics.Based on the elastic constitutive equation of the dielectric EAP, the static analysis of the flexible unit is carried out. The calculation method of spring stiffness is obtained, which can be used for the selection of spring stiffness parameters.Using continuum geometrically exact beam theory(GEBT), combined with screw description method, the kinematics model of the flexible dielectric EAP unit is established. The forward dynamics equation is derived using the screw form of Newton-Euler equation. Based on the visco-elastic electromechanical coupling equation of dielectric EAP, the numerical simulation is carried out in MATLAB. The differential equation is solved numerically by using the finite difference method in MATLAB.A moving unit is constructed by using the dielectric EAP flexible unit. The external force and inertia force of the flexible unit are equivalent to the head coordinate system, and the dynamic equation of the flexible unit is established. By using the Lagrange equation, the dynamic equation of the wheel of the mobile unit is derived.The dynamic response of the model under the step voltage, the sine voltage and the slope voltage is obtained by simulation. The simulation results show that the flexible unit has the maximum response displacement 15.5mm when the power frequency is 3Hz. According to the voltage value of the flexible unit, the time constant of charge and discharge is obtained. The telescopic gait of the mobile unit is simulated at different frequencies. The simulation results and the test results all show that the moving unit has the maximum average speed when the frequency is 1Hz. |
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