| Cabbage is widely cultivated in China.As consumers have higher and higher requirements for the quality of fruit and vegetable products,commercialization has become the development trend of the fruit and vegetable industry,and post-harvest trimming is a key part of commercialization of cabbage.Due to the complexity of the field operating environment and the difficulty of ensuring sanitary conditions,the harvested cabbage was transferred to the processing plants for post-harvest trimming.However,in the processing plants,because cabbage is an ellipsoid-like crop that is prone to rolling,the root pose is inconsistent in the natural state,and high-throughput post-harvest trimming is difficult.Therefore,it is of great significance to study the automatic orientation of cabbage to improve the efficiency and mechanization level of post-harvest repair.Based on previous studies on the orientation of ellipsoidal agricultural products,this paper takes the cabbage variety "Zhonggan No.15" as the research object,and proposes an automatic orientation scheme for cabbage.The main research contents and conclusions are as follows:(1)Study on the physical characteristics and kinematic stability of cabbage.The physical parameters of cabbage were measured,including geometric size,density and elastic modulus.Among them,the plant height range of cabbage was 126.01 ～ 184.78 mm,and the equatorial diameter range was 96.99 ～ 144.51 mm.The cabbage as a whole has the characteristics that the plant height is greater than the equatorial diameter;The friction characteristics of cabbage and different materials are studied.The sliding friction coefficient and rolling friction coefficient of cabbage are measured and analyzed by using the plane sliding method and the energy conservation method,respectively.The analysis of the orientation mechanism of cabbage,by establishing the Euler dynamics equation of the space movement of cabbage,and analyzing the orientation movement of cabbage based on the theory of motion stability,the results show that the rotation of cabbage around the direction of the minimum inertia axis(the central axis)is stable.Provide data support and theoretical basis for the design and material selection of the automatic orientation device of the subsequent cabbage trimming system.(2)Determine the overall plan of the automatic steering device.Based on the stable movement characteristics of the cabbage around its central axis,an automatic orientation scheme based on friction characteristics and an automatic orientation scheme based on image processing were proposed.Based on the accuracy of different root orientation sorting of cabbage,the image-based processed auto-redirection scheme.And compared and analyzed the orientation conveying mechanism,image detection mechanism and sorting and unloading mechanism of the overall scheme of the automatic orientation device.Finally,the roller-type orientation conveying mechanism was selected.The cabbage was rotated to achieve the consistency of its central axis.It is determined that the image detection mechanism uses a deep learning image recognition method to identify the root of the cabbage and determine the orientation of the root of the cabbage;a segmented sorting and unloading mechanism is selected to orient the roots to different cabbages to achieve unloading.Finally,the overall plan of the automatic orientation device of the cabbage repair system was determined.(3)Design key components and control system of automatic orientation device.The structure and parameters of the drive system and rollers of the directional conveying mechanism were designed and studied.The transmission system uses a sprocket and chain transmission to complete the power output and distribution of the steering conveying mechanism.By establishing the mechanical and geometric relationship equations of the cabbage on the rollers of the steering conveying mechanism,it is determined that the parameters of the rollers that meet the operating requirements are: rollers The axial distance range of the wheel is 40 ～ 80 mm,the radial distance range of the roller is 40 ～ 70 mm,and the diameter of the roller range is 57 ～ 135 mm.The kale image recognition and output module is designed to identify the root of the cabbage through the Yolo target detection algorithm,thereby judging the cabbage.The orientation of the roots is 98%,and the root identification information of the host computer is transmitted to the single-chip microcomputer through serial communication.The core of the control system is the single-chip microcomputer,and the hardware models of the motor,solenoid valve,and relay are determined.The control system flowchart and circuit schematic are designed,and the control program is written based on C language.(4)Trial production and verification test of automatic orientation device.According to the overall scheme of the automatic orientation device of the cabbage repair system and the design of the mechanism and control system,the prototype was tested and the control system was debugged.The parameter optimization test was carried out on the cabbage orientation test platform.The single factor test results show that within a certain range of operating parameters,the horizontal angle of the cabbage orientation motion parameter decreases as the diameter of the roller increases,and the vertical angle varies with The diameter of the rollers and the axial distance of the rollers increase and decrease.The optimal working parameters of the device are determined through orthogonal tests.Using the optimal working parameters,a verification test is performed on the auto-turning prototype of the cabbage repair system.When the diameter is 90.00 mm,the axial distance between the rollers is 80.00 mm,the radial distance between the rollers is 62.40 mm,and the linear speed of the roller rotation is 140.00mm/s,the cabbage orientation success rate is 92%,and the working efficiency of the cabbage steering device It was 29.86 pieces/min. |
