A Study For The Electromechanical Regulation Of Dielectric Elastomer And Soft Robot

The conventional concept of robots usually refers to the machines consist of hard components such as motors,hinges,and gears.They are powerful and high-precision,but unable to overcome such challenges as bulkiness,noise,low safety and low energy efficiency.Inspired by the soft creatures in nature,soft robots are made of elastic materials that are capable of generating large and continuous deformation.Compared with the conventionally rigid robots,soft robots can easily change their shape and dimensions according to the task requirements in complex environments,and gains a higher environment adaptability and safety.However,there are still some challenges such as insufficient output power,poor stability,and difficult to analyze and control.As a typical smart material,dielectric elastomer gains the advantages of high energy density,large actuation and fast response,which is potentially contributing in soft robotics,service-oriented robots,aerospace and other areas.This dissertation focuses on the investigation of the electromechanical behavior of dielectric ealsoromer and its application in the field of high-performance soft robots.The main contents are listed below:(1)Based on the electromechanical constitutive relation of dielectric elastomer,the electromechanical tuning of dielectric elastomer by charging rate is investigated.Using experimental method,we studied the force-displacement curves under the constant stretching rate and different limited charging rates.Furthermore,the mechanism is explained using the theory of parallel plate capacitors and dielectric elastomer.The dimensionless model is established and based on which,the physical process is numerically simulated.When the required charging current in the circuit exceeds the limited current by the external circuit,the voltage on the membrane decreases and the force-displacement curve rises.In the dimensionless model,when the limited charging current is smaller,or the initial voltage is higher,the force-displacement curve rises earlier.The research can serve instructions for the harnessing the electromechanical instability and avoiding the electric breakdown of dielectric elastomer by charging rate.(2)A fabrication strategy of the dielectric elastomer actuators is conceived.Meanwhile,a high-performance bionic soft robotic fish is proposed and investigated using numerical simulation and experimental methods.Inspired by the mechanism of manta ray,the robotic fish achieves a tethered speed of 13.5 cm/s(body-length per second,1.5 BL/s)and an untethered speed of 6.4 cm/s(0.69 BL/s).In addition,the soft robot fish has an excellent environmental adaptability,including swimming in a wide range of water temperature of 0?73.4?,high transparency and stealth.Based on the fabrication strategy of the electronic fish,a jellyfish-inspired robot is developed and untethered swimming was realized.(3)A fabrication strategy of the soft robot which is resilient to hydrostatic pressure is conceived.By encapsulated the functional devices in the elastic materials seamlessly,without cavity fusion,and pressure compensation,the soft robot which is resilient to the deep-water environment is realized.Furthermore,a soft fish which is capable of stable swimming under an extreme hydrostatic pressure of 110MPa is achieved.(4)The balance control of electronic underwater robots is studied.Through closed-loop PID control,a buoyancy-adjustment and depth-control of an underwater,inflatable DE membrane structure is realized.The inflatable DE membrane structure and distributed actuators are integrated into an underwater robot,and the attitude adjustment of the underwater robot is realized.The conclusions can be summarized as below:(a)Based on the electromechanical constitutive relation of dielectric elastomer,the electromechanical tuning method of dielectric elastomer by charging rate can be developed.(b)Due such advantages as large actuation,fast response and high energy density.the dielectric elastomer has a broad prospect of application in soft robotics.The fabrication strategy of casting liquid silicone on the artificial muscle to achieve bonding can be used in developing a series of soft electronic robots.(c)Due to the pressure adaptability and compensation of elastic materials,the application of soft robot under extreme hydrostatic pressure conditions can be realized.(d)The balance and attitude control of the DE structure can be realized by the closed-loop control.The related researching method can be extended to the applications of other types of smart materials and structures.