Research On Key Technologies And Equipment Of Screw-Drive Granary Robot

Drain security is related to national security and social stability,and granary management operations are important means to ensure the safety of grain storage.At present,there are problems with time-consuming and labor-intensive granary operations,as well as a lack of labor.There is an urgent need for granary robots to replace manual labor for operations.However,the existing wheeled and tracked granary robots have problems such as complex structure,single function,and weak grain surface driving ability,which cannot meet the actual operational requirements.Therefore,in response to the demand for the development of multifunctional granary robots under the new situation,this paper proposes a screw-drive granary robot that can operate on loose grain surfaces.The mechanical model between the spiral wheel and the grain surface,as well as the driving and operational performance,and motion performance on two-dimensional/three-dimensional grain surfaces were studied.The equipments were developed and the application tests were conducted.The main research content and conclusions are as follows:(1)Research on the mechanical and kinematic models of spiral drive robots on grain surfaceIn response to the mechanism between the spiral wheel and the grain surface,this study analyzed and measured the pressure parameters and shear resistance parameters of grain surface,firstly.Then,based on Bekker Wong’s pressure settlement equation and Janosi’s shear displacement equation,a mechanical equation for the interaction between the spiral wheel and the grain surface was established.The dynamic settlement was corrected through experiments.The numerical simulation error of the model for resistance torque is 15.72%,and the numerical simulation error for hook traction is 16.2%.By analyzing the interaction between the spiral wheel and the grain surface,the grain surface motion characteristics of the spiral drive robot were analyzed,and a kinematic model was established.This study provides a foundation for the design and control of screw-drive robots.(2)Simulation analysis of two-dimensional grain surface motion performance of screw-drive robots and optimization of driving componentsTo meet the requirements of robots traveling and working on two-dimensional flat grain surfaces,a discrete element multi body dynamics coupled simulation model was established to analyze the impact of different spiral wheel parameters on motion performance.Selecting four parameters of the blade height,length,helix angle,and number of blades of the spiral wheel as variables,and using driving speed,slip rate,and traction efficiency as evaluation indicators,single factor simulation analysis and optimization of driving component parameters were conducted.The optimization results show that when the diameter of the float is 110mm,the blade height is 16 mm(h/D=0.145),the helix angle is 32.3°,the blade length is 440 mm(L/D=4),and the number of blades is 4.Based on the optimization results of the ratio of blade to shaft diameter,a Type I screw-drive granary robot was developed and tested.The experimental results show that the Type I granary robot has good two-dimensional grain surface motion performance,and can move forward,backward,and rotate in a relatively flat grain surface environment.The fastest direct travel speed is 0.45 m/s,and the fastest rotation speed is 0.61 rad/s.(3)Optimization of the motion performance of spiral drive robots on three-dimensional grain surfacesGranary robots have higher requirements for driving and working on three-dimensional grain surfaces.On the basis of optimizing the overall structure of the robot,a comprehensive operation index is established to evaluate the granary robot’s grain surface traffic capacity and grain flipping effect.Four parameters,namely pitch,blade height,shaft diameter,and blade number,are selected for simulation optimization of multi factor interaction.The final optimization result is a pitch of320 mm,blade height of 80 mm,shaft diameter of 55 mm,and 2 blades,corresponding to a comprehensive operation index of approximately 0.88.Based on the optimization results,a Type II granary robot was developed,which has the characteristics of high blade to axis ratio.The grain surface traffic capacity of Type II robot is significantly enhanced compared to Type I robot.The fastest travel speed of the robot has increased by 1.2 times to 0.99 m/s,and the fastest rotation speed has increased by 2.08 times to 1.88 rad/s.At the same time,it has the ability to climb a high slope three-dimensional grain surface environment,with a maximum climbing speed of 0.56 m/s on a grain pile with a slope of about 29°.(4)Research on the control strategy and algorithm of a screw-drive granary robotA dual mode control architecture for robot remote control and navigation was constructed.Based on the implementation of remote function,the control algorithm has been studied.A robot positioning system was built based on UWB,with a positioning accuracy of 9 cm.Based on machine vision algorithms,the position of grain piles is recognized,with a positioning accuracy of 241mm.A robot grain surface path control method based on PID control was proposed,providing reference for autonomous robot operation.(5)Experimental study on the operational performance of a screw-drive granary robotFor two application scenarios of grain flipping operation and grain pile leveling operation,practical application experiments were conducted on the Type II grain storage robot under different working modes and operation strategies.For grain flipping operations,the"Z"shaped grain flipping operation has a higher coverage rate than the"Hui"shaped grain flipping operation,with a coverage rate of 92.32%,a work efficiency of 22.73 m~2/min,and a grain flipping depth of151mm.For the flattening operation of grain piles,the"high point strategy"has better flattening effect and higher flattening speed than the"traversing strategy".After flattening operation,the maximum height difference of grain surface is 139 mm,the flattening speed of single grain pile is9.44 t/h,and the flattening speed of multiple grain piles is 15.30 t/h.