Design And Motion-Character Research Of An Inchworm-Like Soft Robot Based On Dielectric Elastomer

The inchworm realizes multimodal-locomotion through muscle contraction,relaxation and coordination of external setae,and has the ability to adapt to complex environment.At present,most inchworm imitators have limited crawling ability under structural load,unable to realize horizontal crawling,vertical crawling,turning movement and other functions at the same time,and do not have the ability to climb inverted.To solve the above problems,an inchworm imitation robot is designed with horizontal,vertical,inverted crawling,turning and load motion functions,and carried out kinematics modeling,controller design and experimental verification and other related researches.The main work of this paper is as follows:A soft robot based on dielectric elastomer actuator and electrostatic adsorption foot is designed to effectively realize the complex multimodallocomotion of inchworm-like robot.A dielectric elastomer actuator with high driving strain is designed to provide the power needed for linear and turning motion of the robot,and its turning motion is realized by the driver of two-block electrode region.To improve the bearing capacity and impact recovery capacity of the robot,an arched frame structure satisfying the kinematic characteristics of inchworm is proposed.To ensure the bristle anchering function during the inchworm movement,electrostatic adsorption feet are designed to generate stable adsorption force.The output displacement and force characteristics of the robot driver and the tangential force and normal force characteristics of the robot electrostatic adsorption foot under different voltage excitation are studied experimentally.It shows that the output performance of the robot driver and the adsorption feet can meet the requirements of multi-mode motion.A total robot model is constructed,which includ electrodeforming force model,elastic restoring force model,total inertia force model and PET motion frame output force model.Aiming at the unknown parameters of the model,the identification experiment methods of physical parameters,static parameters and dynamic parameters of the model are proposed,and the experimental platform is built to test the data of robot manpower,electricity,and displacement under different conditions.To control the motion of the robot,a control strategy combining feedforward and feedback is proposed.The feedforward control is derived from the dynamics model of the robot,and the PID feedback control is used to compensate the hysteresis effect and model uncertainty caused by the creep of DE materials.The two control inputs are superimposed on the designed inchworm soft robot,which have achieved stable tracking of target trajectory.The robot is manufactured and a motion test platform is built.The robot is tested on horizontal crawling,vertical crawling and turning,and the motion function is tested on the scenes of crossing gaps,crossing low tunnels and impact.Experimental results show that the designed robot can achieve a stable moving speed of 1.08 times and 0.71 times of its body length /s in horizontal and vertical planes,respectively.When crawling upside down,the maximum speed of the robot reaches 0.53 body length /s.The robot can rotate at a maximum speed of 16.19/s and crawl at a speed of 0.19 times body length /s when it is loaded with 130g(26 times body weight)on the horizontal planeand,and can effectively track target trajectory.Finally,the robot is applied in the actual scenes.The robot can cross a gap of 18 mm wide,pass through a short tunnel of 30 mm height with 64.45 g load,and recover and continue to move stably after being impacted and trampled by 9945.45 times of its own weight.Full total figures 73,tables 4,reference 89.