| With the increasing improvement of industrial technology, industrial robots have entered a rapid development stage, thus being applied in more and more different fields. However, in the practical application process of industrial robots,some problems have appeared. In some conditions, industrial robots can’t completely operate in the way that people expect. Besides, in the motion process,some unnecessary problems often appear, such as chattering phenomenon and the position displacement of end effectors, which greatly influence the application effect of robots. As the important and precise transmission part of industrial robots, RV reducer is the key to guarantee the precision, load capacity, motion safety and stability in the practical application process of industrial robots. However, currently the theoretical study of dynamics is still imperf, which seriously affects the solution of those problems. Therefore, this paper comprehensively studies the dynamic characteristics of RV reducer from four aspects of reducer efficiency, nonlinear friction, torsional rigidity and transmission precision through experiments by building platform, which will provide a foundation to better control industrial robots in the future.Firstly, the inner nonlinear friction characteristics and of RV reducer are analyzed. And the transmission process and test bench mathematical modeling of RV reducer are set up. Besides, a test bench is built to make friction experiments in terms of RV-40 E. As a result, the Static friction+Coulomb+Stick+Stribeck friction model of RV reducer is identified through genetic algorithm. On this basis,simulation is carried out in terms of the influence of key friction variables on friction characteristics and the transient influence of frictional damping on the system output. And the measurements in terms of nonlinear friction of RV reducer are analyzed.Secondly, efficiency co-simulation of RV reducer model including nonlinear friction characteristics is achieved according to the transmission efficiency characteristics and transmission characteristics of RV reducer through Adams and Matlab and efficiency characteristics is analyzed preliminarily. Then, the test bench of transmission efficiency of RV reducer is built. As the study objects, transmission efficiency of two different-type RV reducers are detected. And the change rules of transmission efficiency curve of RV reducer, its reasons as well as proper measurements are analyzed through data processing.Thirdly, nonlinear model of torsional rigidity of RV reducer is analyzed and theloading device design of test bench is finished. Besides, the test bench of torsional rigidity of RV reducer is built and the rigidity of domestic and overseas RV-20 E and RV-40 E is tested. Thus, linear rigidity and backlash error are analyzed when the two types of RV reducers are in different positions. As a result, it is found that RV reducer shows the hysteretic characteristic in the condition of overload. Through analyzing the experiment results of RV-20 E, the cubic polynomial nonlinear rigidity model of the reducer is built. What’s more, motion simulation of the nonlinear model is carried out to analyze the dynamic influence of different rigidity on the system output of mechanical motion.Finally, according to the transmission precision of RV reducer, the transmission precision test bench of RV reducer is built. And the transmission precision test of RV-20 E and RV-40 E is carried out. At the same time, the error sources in the transmission process of RV reducer are analyzed and the dynamical model of RV reducer transmission is built, including nonlinear torsional rigidity, damping and rotational inertia. And based on the transmission errors tested when RV-20 E is at a low speed, the influence of rigidity, damping and rotational inertia on transmission errors is analyzed qualitatively. As a result, it is found that the rotational inertia,damping and nonlinear torsional rigidity of RV reducer have a direct influence on rotational transmission precision. |
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