Theoretical Analysis And Experimental Study On Variable Stiffness Pneumatic Networks Soft Robotic Manipulator

Soft robot hand,an important branch of soft robots,not only has the advantages of soft robots with changeable shape and size in a large variable range,low pressure impedance,non-destructive contact with soft or fragile items,but also has the ability to bend,extend,shrink,expand,and twist.And it has been gradually becoming a research hotspot.Pneumatic networks drive,a typical way of actuation,has also received extensive attention because of its unique advantages,such as large output force,fast response speed,small size,light weight,large deformation,good man-machine interaction ability and low price and easy promotion.Based on the above,this thesis designs a pneumatic networks soft robot hand based on granular jamming.The main research work includes:The ABAQUS-based structural parameters optimization method for pneumatic networks soft manipulator was studied,and experimental research mainly focused on the effect of different material combinations on the performance of pneumatic networks soft manipulator.To facilitate the selection of the reasonable structure size parameters conveniently for pneumatic networks soft manipulator,this thesis firstly analyzed the curvature radius and internal stress distribution using ABAQUS finite element software,and optimized the structure size parameters according to the results.This will provide a reference for later generations in the selection of structural parameters.According to the actual operations and comparative analysis,the casting process was improved.Three different types of pneumatic networks soft manipulator were cast using the improved process.Through experiments,the effect of material properties on the flexural and distal forces of the pneumatic networks soft manipulator was comparatively analyzed to provide a strong reference for material selection.A new variable stiffness pneumatic networks soft manipulator based on granular jamming was investigated,which effectively improved the stiffness of the soft robot hand.Through experiments,it was found that the pneumatic networks soft manipulator has some certain deficiencies in stability and resistance to deformation.In this thesis,a novel variable stiffness pneumatic networks soft manipulator based on granular jamming was designed and implemented.The stiffness can be varied within a certain range,which improves the above deficiencies to some extent.Grabbing tests between two kinds of pneumatic networks soft robot hand before and after variable stiffness were analyzed and compared.It is convenient that two kinds of soft robot hands made of two kinds of manipulators respectively to further compare the difference between the pneumatic networks soft manipulator and the novel variable stiffness pneumatic networks soft manipulator in practical applications.Then the physical grasping ability experiments were performed respectively,and the respective maximum gripping force were obtained in different pressures.The research results further validate the necessity of variable stiffness and provide important guide for the design of this type of robot hand.