Design And Test Of Follow-up Chestnut Receiving Vehicle Based On UWB Positioning Technology

Chestnut has been planted in China for more than 2000 years.The planting area and yield of chestnut in China rank first in the world.At present,the chestnut harvest is mainly based on the traditional manual harvest,which is faced with the problems of high labor intensity,easy to hurt chestnut bracts,low harvest efficiency.Chestnut trees are primarily grown in hilly mountainous regions in China,making it impossible to use huge harvesting equipment there.Some miniature chestnut harvesting machinery still suffers from issues like high labor intensity and poor harvesting efficiency,which makes it unfit to satisfy the demands of industrial development.In response to the above problems,this thesis designs and achieves a follower type chestnut receiving vehicle based on UWB positioning technology.The receiving vehicle can smoothly follow the movement of the chestnut beating fruit drop device installed with UWB positioning tags.And the chestnut receiving vehicle can realize the collection of chestnuts when the harvesting device is in working state;at the same time,the chestnut receiving vehicle can adapt to the complex terrain of the chestnut plantation and has good passability.It accomplishes the efficient collection of falling chestnut fruits and has certain positive aspects to support the mechanical and intelligent harvesting of chestnut.The main research contents of this paper are as follows :(1)The overall scheme of receiving vehicle is determined.According to the growth characteristics and planting mode of chestnut,the receiving device and walking chassis of the receiving vehicle are designed.Calculate the driving power of the receiving vehicle chassis under different working conditions,and complete the selection of the chassis drive motor;finally,the prototype of chestnut receiving vehicle is built.(2)Design and simulation of chestnut receiving device.Determine the design of the chestnut receiving device according to the working theory of the chestnut harvesting device and the real collection target,Determine the design of the chestnut receiving device.The impact force generated by the collision between the chestnut and the receiving device when the chestnut is beaten and dropped is calculated.The stress,strain,and displacement diagram of the umbrella bone rod following the chestnut collision is derived by the use of finite element simulation.To assess the system’s rationality,a dynamic simulation of the receiving device’s umbrella opening and shutting mechanism is run..It is determined whether the structure will not be destroyed in its operational state and that it satisfies the strength criteria by performing a static analysis on the support foot frame and support bottom plate of the receiving device.(3)UWB servo system development and application.UWB positioning technology is chosen as the positioning scheme of the chestnut receiving vehicle after weighing the benefits and drawbacks of alternative positioning techniques.It is proposed that the chestnut receiving vehicle cooperates with the chestnut harvesting device to achieve the goal of real-time collection of fallen chestnuts,and the servo system’s hardware is chosen and constructed.A Kalman filter is employed to investigate the tag’s fluctuating location,and the UWB positioning approach is examined in order to enhance positioning outcomes.Finally,through MATLAB simulation,the observation noise of the system was found to be reduced by 57.1%(4)The performance test of the chestnut receiving vehicle prototype was carried out.The calibration test of UWB positioning module is carried out.The test results and the actual results are fitted into a linear function,and changes are made to the module’s internal program to increase positioning accuracy.To confirm the viability of the system design,performance tests for static and dynamic positioning are performed.The field chestnut receiving test was carried out.The average collection rate of the follow-up chestnut receiving vehicle with the chestnut harvest beat type fruit drop device was87.76 %,and the average collection rate with the handheld multi-functional nut harvester was 94.23 %.The test showed that the chestnut receiving vehicle could meet the requirements of collecting when the fruit fell.