Research On Design Of Blueberry Grasping Soft Manipulator Based On Contact Mechanics

The packaging,transportation,grabbing and grading of blueberries are important links in the production process.At present,there is little research on the mechanical damage caused by stacking of blueberries in packaging,and the sorting of blueberries in my country is still mainly manual.Research on the mechanical properties of blueberries is beneficial to reduce the mechanical damage of blueberries in the process of packaging and grading.The end effector of blueberry grasping is a key component in the grasping process,which directly affects whether the blueberry grasping process can be successfully completed.and damage to blueberries.This paper studies the mechanical properties of blueberries and the soft manipulator,and designs a software manipulator suitable for blueberry grasping.The main research contents are as follows:Test of mechanical properties of blueberries.Through a single blueberry compression test,the mechanical parameters of the blueberry were obtained,the elastic modulus was 0.225 MPa,the Poisson’s ratio was 0.35,combined with the simulation and test results,verified the accuracy of the parameters,and provided basic data for the blueberry stacking simulation.Blueberry stacking experiment and simulation.Three important factors affecting blueberry stacking damage were selected,the number of stacking layers,loading speed and placement direction,and an orthogonal test was designed with the breaking force as the response index.The test results showed that the three factors have a significant impact on blueberry stacking damage.The order of influence size is placement direction>stacking layers>loading speed,and a regression model between the three factors and the response is established.Using the ABAQUS software to simulate the two extreme situations when the breaking force is the largest and the smallest,the stress distribution during the blueberry stacking process is obtained.The upper layer of blueberries will suffer more damage,while the lower layer of blueberries will suffer less damage,mainly because the blueberries in the upper layer absorb a lot of energy and have a certain buffering effect.The design of the soft manipulator.Designed and modeled the pneumatic soft manipulator,and took fingertip displacement and fingertip rotation angle as response indicators,combined with three important factors,finger length,wall thickness,and knuckle spacing to carry out research on the effect of bending performance,and designed three factors and three levels Orthogonal experiment and simulation using ABAQUS software.The results show that the three factors have significant effects on the fingertip displacement and fingertip rotation angle of the finger,and the order of influence is finger length>wall thickness>knuckle spacing.Based on the Yeoh model,regressions between factors and responses are established.According to the model,the best factors for bending performance were finally obtained according to the model.Finger length: 70 mm,wall thickness: 2 mm,and knuckle spacing: 1 mm.Finger making and construction of test bench.According to the parameters of the finger,complete the modeling of the relevant mold and use 3D printing technology to make it,and finally complete the injection molding of the finger.The blueberry grabbing test bench was built and the blueberry grabbing was realized.