Research On Rotating And Climbing Soft Robots Based On Vibration Drive

Traditional rigid robots,generally comprised of motors,pistons,hinges and other rigid components,have the advantages of large power and high accuracy,but inevitably have the disadvantages of heavy,noisy,poor environmental adaptability and low energy efficiency.Soft robots are usually made of soft materials,which can theoretically achieve unlimited freedom,withstand large and continuous deformation,and compliantly contact,making soft robots in rehabilitation medicine,human-machine cooperation,and complex environmental movements(marine exploration,terrain detection)and other fields have broad application prospects.However,soft robots are also difficult to precise control,lack of power,and other shortcomings.It is necessary to design a new drive structure through multi-disciplines such as machinery,mechanics,electronics,computer,biology and chemistry,and using new materials and new drive technology to solve the shortcomings of soft robots.At present,soft robotics have become one of the hot directions in the field of robot research,which has important theoretical value and engineering application significance.In view of the shortcomings of the existing soft robots,such as slow rotation speed and difficulty in movement in narrow slots,ruins and other environments,this thesis designs two soft driving structures that can realize rotating motion and climbing motion based on the principle of vibration driving from the perspective of bionics.From the perspective of theory,numerical simulation and experiments,the driving characteristics and potential engineering application capabilities of rotatable and climbing soft robots are studied.The main research results are as follows:(1)Based on the vibration-driven theory,the soft rotating and climbing robots are designed with different arrangements of tentacle,and the two soft robots are theoretically modeled and the governing equations are given.The array of tilted antennae at the bottom of the rotating soft robots is uniformly arranged along the circumference direction.When the circular end face of the soft structure is subject to a uniformly distributed periodic excitation force,frictional force will be generated along the tilting direction of the tentacle,thereby providing rotation driving force.For climbing soft robots,the array of tentacle is arranged uniformly at a certain inclined angle along the axial direction.When the inner wall of the robots is subject to a uniform distribution of periodic excitation force,the structure will generate friction along the inclined direction of the tentacle,which can provide the driving force for axial forward.(2)The motion mechanism of the rotary soft robots was analyzed by ABAQUS finite element simulation.The antennae of the rotating soft structure are driven down and up periodically by vibration generated by the piezoelectric bimorph.During this process,the static friction force generated is greater than the sliding friction force during the upspring process,thereby a circumferential driving force is generated and rapid rotation can be realized.The rotary soft robots were prepared by using piezoelectric bimorph as the driving source.The motion of soft robots under different voltages,frequencies,and geometry of this robot are analyzed.The results showed that the applied voltage Vp-p by the rotating soft robots with the geometric parameters of?=60°,length(l)=7 mm,and distance(d)=1.6 mm,and is 400 V,and the frequency is1400 Hz,and its rotation speed can reach 118.3 r/min,which is higher than the speed of the pneumatic rotary soft robot reported currently.(3)The overall design plan,preparation technology and process of the vibration-driven wireless climbing soft robots were described.The motion law of the vibration climbing soft robots in the tube was studied by ABAQUS finite element simulation,and the linear motion and wavy motion depending on the pipe diameter were obtained.The axial driving force of the climbing soft robots is provided by the friction force between the robot's antennae and the inner wall of the tube.By analyzing the climbing speed of soft robots made of materials(hydrogel,silicone,rubber,polyethylene)with different Young's modulus,the results show that the soft robots made of silicone have good motion performance.The effects of length and angle of the robots'tentacles on the climbing speed of the robots in the tube were studied through experiments,which basically conforms to the predicted results of the theory.The effect of voltage on the robot's load-bearing capacity and the effect of the load size on the climbing speed of robots were discussed.The results showed that structural parameters of?=60~o,l=6 mm,d=2 mm can reach 62.1 cm/s when applied voltage is 5 V and a pipe diameter is 22 mm.When the applied voltage is 3 V and diameter of tube is 21 mm,its maximum load can reach 94.8 g,which is 14.8 times its own weight.By comparing the climbing speed of some soft robots and animals in nature,the volume and speed of the soft robots designed in this paper are similar to that of the natural biological gecko,and it has the advantages of small size and fast moving speed.(4)Adaptive climbing soft robots and multi-configuration soft robots were designed for the climbing application of pipes with different diametral and different shapes(square pipe,triangle pipe,etc.),and their climbing feasibility was verified by experiments.Its feasibility of climbing.The experiments have shown the ability of vibration-driven climbing soft robots to work in unstructured environments.The results show that the robots can smoothly pass through narrow slots and rocky terrain,and the speed of the robots can reach 0.95 cm/s in rocky terrain,and the speed can reach 22cm/s in narrow slot on uneven surface.In this paper,the vibration-driven rotation soft robots and the climbing soft robots are studied through the theoretical,finite element analysis and experiments,which provides new ideas for the design of new driving soft robots,and provides theoretical and experimental guidance for the applications of climbing robots in the environment of inside and outside pipe,narrow slot and pothole surface.