Research On Pneumatic Soft Self-sensing Bending Motion Module

Soft robots have become a research hotspot in the field of robotics due to their strong deformability,high flexibility,and safe interaction.However,its deformation is complex and it is difficult to realize accurate sensing.It is urgent to develop a sensor technology with low modulus and stretchable deformation that does not affect its own deformation and realizes feedback control of the robot.At present,some scholars have conducted research on flexible sensors.Conductive composite materials are prepared by filling flexible base materials with conductive liquid metal,water ion conductive materials,conductive nanoparticles,etc.,and use attachment or embedding methods to realize deformation signal sensing,but There are still problems such as flexibility and strain transmission loss,insufficient precision,and insufficient compact structure.Therefore,this paper proposes based on the piezoresistive effect of conductive flexible polymer and the design principle of micro-opening shape,comprehensive material modulus,motion deformation and other factors,balances the flexibility of deformation and sensitivity,builds a drive-strain sensing integrated software motion module,and conducts experimental research.Firstly,based on the conductive passage theory,a conductive flexible composite was prepared by mechanical blending using low modulus silione as substrate,multi walled carbon nanotubes and nickel plated carbon fiber as conductive filler.The static characteristics of the sensor unit were tested by experimental characterization method,and the influences of different conductive filler ratio on the mechanical/electrical properties of conductive composites were studied as well.With the purpose of low modulus and high sensitivity,the ratio of conductive filler was optimized.On this basis,the dynamic characteristics of the soft sensor unit are studied,and the relationship between its resistance and strain relationship could be established,laying a solid foundation for the subsequent design of self sensing soft robot.Secondly,based on the pneumatic grid structure and flexible conductive sensing unit,a soft movement module with large deformation capacity is designed,which integrates structure with sensoring.The whole motion module is divided into strain layer,sensing layer and constraint layer from top to bottom.The strain layer adopts the aerodynamic grid structure of single cavity and multiple air chambers.The restraint layer restricts the axial deformation of the bottom of the module,resulting in the asymmetric deformation of the module along the axial direction,so as to realize the bending movement.The sensing layer is composed of three sensing units evenly distributed,with the resistance change rate?R/R₀,that is,the sensitivity,as the foothold.The hollow shape is optimized by using ANSYS Workbench simulation software,after which the sensing unit could be prepared,and its performance could be tested and characterized.On this basis,the overall preparation of the motion module is completed.Finally,to build a soft robot system,a adjustable-speed stepper motor with charging/discharging driving mechanism is designed,build software module control system.Based on the free bending of the motion module without load,the motion calibration experiment of the module sensor unit is carried out,and the configuration of the module motion attitude is reconstructed.After that,the crawling robot and the soft gripper are designed to complete the crawling experiment of the crawling robot in the variable height pipeline and the grabbing experiment of the soft gripper,during which the variable resistance value in the movement process is directly output,the reconstruction accuracy is highly realized,and the self sensing function of the deformation module is basically verified.