| Joints of traditional robots are mostly adopted pure rigid driver, which essentially do not have the ability of active variable stiffness. Those robots have the advantage of fast response,the accurate control of speed and position. But those robots’energy consumption is large. Active and passive safety of them is not high, and the robots’adaptability to the work environment is poor, needing to work in the specific structured environment. As robots are widely used in different fields, them are usually required to complete a variety of complex tasks that even need to interact with people, that put forward higher request of robots’ flexibility and the ability to adapt to the environment. Therefore, in order to make that be safer when the robots interact with people or other task object, and to make the robots having good adaptability in the unstructured environment. In the future, the key research contents in the field of bionic robot is that make them has good flexibility, active and passive variable stiffness, high energy efficiency of the bionic. The stiffness of human’s joints can be forwardly adjusted by the tendons. The outstanding performance of the bionic robot is embodied in making the robots’joints like human’s which can be adjusted muscle in different position so as to adapt to different environment, reducing energy consumption and ensuring safety. Therefore, the research of the active or passive adjusted driver’s stiffness and variable stiffness driver execution which has the inherent vibration frequency has important practical significance. Based on a kind of antagonism institution of slider-crank mechanism, this article proposes a kind of bionic variable stiffness driven joints,and make deep research of the kind of unlinear variable stiffness characteristics. In the end of the article, the variable stiffness elastic element is applied to the shoulder and elbow joints of the bionic robot, and its 3D virtual model is set up. The main research contents include the following:1. Studying existing variable stiffness devices element of mechanical structure and the principle of variable stiffness. Determine the form of variable stiffness used in the article. Putting forward a new kind of counter variable stiffness elastic driver based on the slider-crank mechanism.2. Establishing the kinematics model of double crank slider mechanism. Analyzing the kinematics and statics characteristic of double crank slider mechanism. Finding some mutation point of the force and velocity. Planning working range where can practically apply to. Preparing for the further analysis of subsequent variable stifmess characteristics.3. Building kinematics and mechanics model of the bionic antagonistic variable stiffness driven joints. Analyzing its variable stiffness characteristic. And optimizing structure of variable stiffness elastic drive joints by MATLAB. Determining parameters such as optimization radius of the crank and pulley and distance from a pulley to a crank hinge. Then, emphatically analyzing and studying the isometric contraction of variable stiffness elastic element and the characteristics of isotonic contraction, in order to lay a solid theoretical basis for its practical application in the future.4. Establishing ADAMS virtual prototype model of variable stiffness elastic element, especially for steel rope. Simulating the kinematics, statics, dynamics and the characteristics of variable stiffness of variable stiffness elastic, which are contrastive analyzing with the results of the MATLAB.5. Designing the SOLID WORKS structure of the bionic antagonistic variable stiffness driven joints. Establishing a 3 d model of the variable stiffness elastic element and bionic robots’arms. Determining the way of fixing, fitting, installing variable stiffness elastic element and related parameters of drive components... |
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