Design Of The Rotation Numbers Counting Device For Frequent Start-stop Shaft

The rice test plot is a base for selecting good breeds,improving cultivation techniques,and conducting variety comparison experiments.In the experiments of rice breeding,breeding of improved varieties,cultivation,and soil fertilizer in agricultural plot,the quantitative sample interpolation is required within the area of specific unit plot.At present,the intelligent agricultural equipment about the field seedling transplanting has matured,however,the intelligent equipment of the transplanter for the quantitative transplanting operation in the plot test is still lack of researches.Professor Zhao Zuoxi in South China Agricultural University and his group have developed a counting device for quantitative transplanting of rice transplanter,which is mainly based on hall sensor’s measuring the number of rotations of the transplanter shaft to realize the transplant counting.The device is divided into two parts: a counting signal acquisition device and a counting display device,basically achieving the transplant counting.Though there still remains many problems under the operating condition that the shaft starts and stops so frequently.Such as the insufficient stability in the structure of counting device.The design of the mounting parts and the fixed position of the relevant part of the sensor are unreasonable.The counting device is inadequate to ensure a satisfiying counting accuracy at the start and stop times.There is no complete analysis and installation method for the problem of inaccurate counting of start and stop times.The device can not be generally applied without complete design and installation procedures,which means the counting device cannot be broadly promoted.This article studies the above issues and improves the device as follows:(1)The structure of the counting device is improved by using the design principle of minimum measurement loop and minimum intermediate links as the design principle.In the original scheme of the counting device,the mounting base for fixing the Hall sensor is fixed by a plurality of intermediate adapter plates,and the permanent magnets of the sensor part are directly adhered to the universal joint.This design results in too many intermediate links being vulnerable to vibration.And it is difficult to install and debug the device.In the design process,the structure optimization design is gradually completed,and the hall sensor with smaller size and more convenient installation is selected.And the mounting base is no longer used in the later scheme,using a more convenient flexible mechanism to fix the magnet.This design reduces the influence of vibration on the hall sensor counting and improves the stability of the counting device.(2)By putting forward a more complete installation and debugging method,the problem of counting accuracy under frequent start-stop operating conditions is solved.The device may count one time more or less when the transplanter is frequently started or stopped.The reason is that there will be static position error and dynamic rotation error when the planting axis starts and stopps frequently,resulting an imcomplete cycle of the planting axis.In other words,there will be an error angle range in counting.This paper solves the problem of counting accuracy by analyzing the position of the counting error interval,calibrating the measurement reference,setting up the angle of the test platform to measure the error interval,and finally proposing a complete installation and debugging method.Based on the above method,the measurement error angle range of the test platform of the test device is built,and the counting accuracy of the counting device is tested and verified.(3)Proposed complete installation steps to improve the versatility of the counting device.On the basis of solving the problems existing in the original plan,a complete installation procedure was proposed and successfully installed on the two rice transplanter types with and without fertilization to lay the foundation for future product promotion.(4)Tested verification of the final counting device scheme.Through the counting test and the field operation test during the non-working of the rice transplanter,the scheduled number of transplants and the actual number of transplants are verified,and the stability of the counting device in the actual working environment is also checked.