Design And Research Of Apple Canopy Profiling Manipulator

China is a big apple-producing country,and Xinjiang is an important apple-growing Province in China.Mechanization is an important development trend of forest and fruit industry.With the improvement of apple yield,agricultural modernization and the development of agricultural intelligence,it is urgent to develop multi-degree-of-freedom working arms for standardized apple orchards to solve the shortcomings of existing machines in pesticide spraying,shaping and pruning of orchards.In this thesis,by designing multi-degree-of-freedom shaping working arms for Apple orchards,the foundation is laid for realizing shaping spraying and pruning of orchards,and the adaptability of working arms to different tree-shape specifications and agronomic characteristics is improved.Improve pesticide utilization,fruit pruning efficiency,mechanization level of orchard and operation quality.This subject summarizes the research status of fruit canopy biomimetic mechanism at home and abroad by consulting literature.Based on field research,main parameters of canopy shape of standardized orchards and combined with research status at home and abroad,the overall design scheme of copying working arm is determined.Further design and check the parts of the working arm,simulate and analyze the dynamic characteristics of the working arm,verify the rationality of the structural design,and establish the dynamic model of the working arm by Lagrange equation method to solve the driving force or torque required by the movement of the working arm.The crown information acquisition and profiling positioning control system is developed.With the ultrasonic sensor and RS485 communication protocol,the real-time data transmission between the ultra-close sensor and the single-chip computer is realized.The target distance and the current distance of the working arm are compared.The DC motor is driven to the target distance by the position PID controller to achieve the crown profiling of the working arm.Complete the trial production of hardware and software system integration and prototype of work arm.The height,crown and row spacing of standardized apple orchards are 3000-5000 mm,1500-3000 mm and 3000 mm respectively.Dual rocker arm is adopted as the overall contouring scheme to complete the parts design and selection of the contouring working arm.The maximum working height of the working arm is 5370.94 mm,the width of one-sided profile is 2812.47 mm and the horizontal expansion range is 1780～2506 mm.One-sided working arm has 5 degrees of freedom of rotation and 3degrees of freedom of translation.ANSYS/Work Bench is used to determine that the first six natural frequencies of the assembly of the copying working arm are 13.083 Hz,13.454 Hz,15.867 Hz,21.858Hz,48.552 Hz,57.726 Hz respectively.The excitation frequency during trimming operation is 39.9 Hz without resonance.The Lagrange equation method is used to establish the dynamic model of the bionic working arm,and the relationship between the driving force required by each joint and the joint(angular)velocity and acceleration is determined,which lays a foundation for the motion control and trajectory planning of the working arm.The results of ADAMS simulation show that the acceleration and force of each joint(angle)change smoothly without impact.The work arm copying control system is developed and the hardware selection and software design are completed.The PID parameters are set to K_p=100,K_i=0.1 and K_d=500.The prototype was trial-manufactured and the control system was installed.The results of prototype test showed that it meets the agronomic requirements of standardized apple orchard fruit trees.The working arm takes 15.71 s from the initial state to complete the contouring,and the contouring efficiency needs to be improved.The driving motor can be replaced to improve the running speed in the future.After profiling,the average distance between the working arm and the crown is 33.7%and 6.7%respectively between the crown contour point and the working arm contour distance and the target distance 500 mm.The profile accuracy meets the design requirements.