| Under the policy background of "Made in China 2025" and "the 14 th Five-Year Plan and the Long-Range Objectives Through the Year 2035",accelerating the upgrading of China's traditional manufacturing industry,deepening the implementation of the manufacturing power strategy and accelerating the development of modern industrial system are aimed at promoting the development of China's high and new technology.Manipulators are widely used in the field of industrial production in our country.But most of the manipulators are only suitable for their own workplace,and can not be clamped under a variety of different conditions.Therefore,it is very important to study the clamping characteristics of the manipulator,which provides a certain reference value for the later research of machine tactile perception.The clamping state and characteristics of the flexible two-claw manipulator are studied.The contact problem of the flexible contact is studied by using contact mechanics theory and finite element analysis.The stress and strain of the flexible contact under different stress conditions are analyzed,and three different clamping states are obtained.The experimental scheme of the three contact states was determined,and the contact force and slip under each contact state of the multi-dimensional contact measurement platform were obtained,and the relationship between normal force,tangential force and slip was obtained.The main research contents are as follows:Firstly,the theory of contact mechanics and tribology is introduced to illustrate and demonstrate.From the Hertz contact theory with no friction in the ideal state to the Coulomb frictional tangential slip theory with friction in practice,the constraint model of hard finger contact and soft finger contact is analyzed respectively according to the contact constraints of fingers.Then,the finite element analysis of the passive contact problem of flexible contact is carried out by using the finite element software ABAQUS.The different contact states of the flexible contact were obtained under different stress conditions in the contact model,and the contact problems at the micro level in the contact were analyzed.The subjective motion process of the contact model in different contact states is obviously different and has its own specificity.Then the stress and strain in the contact process in each state are analyzed emphatically.Finally,Finally,a multi-dimensional contact measuring flexible robot hand platform was designed to determine the experimental objects and conditions.According to the results of the contact process of finite element simulation,the experimental scheme is determined.By changing the mass of the clamping object and the size of the main drive current,the characteristics of each contact state are revealed,and the influence on the clamping characteristics of the contact process is revealed.The clamping characteristics of the flexible manipulator with multi-dimensional contact measurement were analyzed under three contact states,and the relationship between normal force and tangential force with time was obtained.At the same time,by increasing the rising speed of the manipulator,the sliding time in the asymptotically stable contact state will decrease,and the contact force in the stable clamping stage will decrease.The contact force increases at the late stage of fast steady contact and sliding unsteady contact.Moreover,the ratio of tangential force and normal force also provides a reference to whether the manipulator is holding the object in a stable state. |
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