Design And Analysis Of Pneumatic Gripper With Embedded Endskeleton Resisting Out-of-plane Bending

The soft pneumatic gripper has flexibility,compared with the hard-body manipulator,the bending shape of the gripper can be changed according to the shape of the object to be clamped,so that the body can achieve greater clamping force.The soft pneumatic gripper can keep the clamped object evenly stressed under the action of higher pressure,and it is not easy to damage the object.This paper proposes a bionic endoskeleton software pneumatic gripper,which has a human finger-like gripping mode,which can realize fingertip gripping,finger and palm gripping together.The design of the gripper is inspired by human fingers and ordinary pneumatic grippers.The multi-chamber software pneumatic gripper structure is adopted as a whole.The endoskeleton is embedded in the bottom of the pneumatic gripper for support when clamping objects.The endoskeleton is made of PLA material through 3D printing technology,which has high production accuracy and simple production process.The entire soft pneumatic gripper is made by casting,and the mold is made by 3D printing.Aiming at the four commonly used silicone materials: Ecoflex 00-30,Ecoflex 00-50,dragon skin 10,dragon skin 30,uniaxial tensile test and simulation analysis are used to determine the stress-strain relationship of the material,and analyze the relationship between different materials and the software.Due to the influence of pneumatic grippers,Dragon skin 30 is selected as the material of the soft part of the bone gripper in this article.The constitutive model of the gripper material,the movement model of the gripper,the bending mathematical model and the fingertip angle model are respectively studied to determine the movement state of the gripper.Numerical simulation analysis of the endoskeletal jaws is carried out,and the performance of the endoskeletal jaws under different air pressures is obtained.The simulation results of a single internal bone jaw show that with the increase of air pressure,the bending angle of the jaw will gradually increase,and the fingertip force will gradually increase.At 60 k Pa,the bending angle of the gripper reaches a maximum of 45.5°.The simulation results of the two clamping jaws show that the clamping jaws can realize the parallel contact of the fingertips under the action of 40 k Pa air pressure.The results of a single experiment verify the results of the simulation experiment,and the maximum bending angle of 50° is reached at 60 k Pa.The gripping experiments of the jaws show that the endoskeletal jaws can achieve anti-torsion characteristics.Carry out clamping experiments on objects of different sizes and shapes.With the support of the inner bones of the fingertips,smaller objects can be clamped,and the entire fingers can be combined with the palm to clamp large objects.Experiments on clamping objects with different shapes and rigidities show that the clamping jaws can achieve the clamping of objects with different rigidities without causing damage to the objects.Experiments on clamping objects on the desktop show that the clamping can adapt to the clamping environment of the objects on the desktop.