The Virtual Prototype Modeling And Performance Simulation Of Cleaning Unit

This subject has introduced the development status of cleaning unit of the domestic andforeign rice combine and analyzed the features of different cleaning units. The air and screencleaning mechanism is selected since it aims at harvesting rice in the hilly areas. This paperanalyzed the force which the sieve and airflow exerted to the rice materials in the cleaningmechanism synthetically by considering one kind of rice combine as a prototype and built amathematic model of movement from concave grate to vibrating screen. What’s more, itanalyzed several kinds of motions such as relative motion and throwing movement andconditions that they have to fulfill. At the same time, the paper built a screen-penetratingprobability model of rice by analyzing them how to penetrate two layers of vibrating screen.These works are the theoretical bases for searching for optimal parameters and improvingdesign.The cleaning unit has been adopted the structure of two fans and two f vibrating screensand been built a solid model by using the3D design software Pro/E. In this thesis, the authorapplied ADAMS to analyze motion of virtual prototype for researching the motion of rice inthe vibrating screens when set different working parameters. The author considered thescreen-penetrating probability and loss rate of rice as the cleaning indices and consideredcrank rolling velocity, the length of crank, flow fan velocity, wind direction angle and theinstallation angle of the screen surface as the factors of experiment. The author has done themulti-factor and multi-level simulation experiment by using the experimental design ofuniform distribution and gained the values of cleaning indices when the unit had been setdifferent parameters and found the optimal parametric combination. The model of the relationof the indices and factors was found by using regression analysis and the optimal workingparameters was got through applying the optimization toolbox in MATLAB to do themulti-objective optimization. Finally, the parameters of the virtual prototype were improvedin the simulation software and the optimal results were verified by simulation test.This subject is on the basis of theoretical analysis of the movement of rice material in theairflow and on the sieve surface, carried on a simulation experiment of virtual prototype withutilizing advanced simulation software, and set up mathematic model about cleaning indicesand some significant factors. The study improved the structure parameters of the cleaning unitand will provide a reference for improvement of the cleaning quality and overall performanceof combine.