Structure Design And Dynamics Study Of A New Type Of Inverted Umbrella Fruit Collecting Mechanism With Clearance

Forest fruit collection is one of the more important links in the process of forest fruit harvesting,and mechanized collection is of great significance for improving the productivity of the forest fruit industry.The existing forest fruit collection device occupies a large space,and applying the folding mechanism to the forest fruit collection device can effectively solve this problem.However,the system vibration caused by the collision between the secondary elements at the joint clearance can have a serious impact on the motion accuracy of the folding mechanism,which is not conducive to its expansion and retraction.This paper first conducts the overall structural design of the vibration harvesting integrated machine,which consists of five parts in total.It mainly introduces the design process of a new inverted umbrella type collection device.The collection device is divided into three parts: a new folding and unfolding mechanism,a tree holding and clamping mechanism,and a clamping ring.The structural design and kinematics analysis of the mechanism are carried out,and the deformation design of the umbrella arc surface is realized through NX parametric design;This paper uses the mean square error method to optimize the size of each rod in MATLAB,and uses ANSYS to analyze the stress and deformation of the rod after the fruit falls into the collection surface,to determine whether its strength and deformation meet the requirements.Secondly,dynamic simulations were conducted on the new folding and unfolding mechanism and the new inverted umbrella collection mechanism in ADAMS,and a contact force model with clearance joint links was established,Study the effect of joint clearance on the motion performance of the mechanism through the secondary development of ADAMS embedded in the mechanism simulation model.To achieve the discrimination of contact modes and the solution of contact forces between the pair elements at the joint with clearances,a subroutine for calculating contact forces is written based on FORTRAN language,and this program is used for the simulation calculation of a new type of folding mechanism with clearances.Then,code is written in MATLAB to calculate the singular spectral entropy,and the singular spectral entropy is used to quantitatively analyze the nonlinear behavior of hinges with clearances.This paper come up with a new nonlinear quantitative analysis method to provide theoretical reference for the nonlinear quantitative analysis of mechanisms with clearances.Finally,rubber and plastic were selected as raw materials for the prototype processing of the new inverted umbrella collection device,And conduct experiments to verify the tree holding and stretchability of the processing prototype.The effectiveness of the tree holding mechanism was verified by selecting tree bodies with different trunk diameters and trunk surfaces for tree holding experiments.The correctness of the virtual prototype simulation has been verified through expansion and retraction experiments on the processing prototype.Comparing the theoretical trajectory,considering hinge clearance trajectory,virtual prototype trajectory,and processed prototype folding trajectory,the design accuracy of the bionic folding mechanism was verified,and the accuracy of the contact force model with clearance hinge links was also verified.