Research On Dielectric EAP-actuated Robotic Manipulators

Dielectric EAP is a new kind of intelligent material, performance of which is similar to naturalmuscle, such as high energy density, fast response speed, large deformation and strong adaptability toenvironment etc, and has a broad prospect of application in the robotics fields, for example,rehabilitation training, force feedback etc.On the basis of the Dielectric EAP deformation principle and working process of dielectricelastomer actuators (DEAs), a type of rolled DEAs has been designed and manufactured. Meanwhile,the platform used for pre-stretching the EAP film and the semi-automatic winding device formanufacturing the rolled DEAs have been designed and implemented, and both of them can improvethe rolled DEA’s manufacturing quality and efficiency.Based on the biological joint’s agonist-antagonist driving principle, a rotational joint which isdriven by rolled DEAs has been designed. Finite element simulation on dielectric EAP is conducted,and the parameters of DEAs are determined according to the simulation results. The rotation angle,loading characteristics and blocking moment have been tested: output rotation angle is about10.5°,and the blocking moment18.33mN·m.According to the elastic deformation theory, the electromechanical coupling model of dielectricEAP has been established, and the relationship between input voltage and output rotation angle can beobtained by solving the differential equations, but it’s time-consuming. To avoid the complicatedcalculation, CMAC (Cerebellar model articulation controller) neural network and PD controller arecombined to achieve the nonlinear mapping between output angle and input voltage. Tracking controltests have been done by tracking step and sinusoidal reference signals, and the reasons for responsetime and tracking error are analyzed.Combined with the working principle of rotational joint, a type of2-DOF manipulator, which isdriven by dielectric EAP, has been designed and implemented. According to the manipulatorrequirements, the control circuit is constructed and the control program is finished to realize the controland state monitoring of manipulator movement, and then achieved to controlling the end ofmanipulator by tracking a circle. The electrical mechanical property of DEAs was measured underdifferent lengths and voltage. The working voltage of DEAs has been calculated according to theoutput force and position of manipulator in operating space, and also compared output force with the measurement results. By improving the performance of Dielectric EAP driven manipulator, it could beapplied to rehabilitation training, force feedback of micromanipulation and so on.