Design and optimization of swing arm loading and unloading structure of monorail conveyor for hilly orchard and tea garden

Objective To solve the problem of single function of existing transportation machinery for hilly orchard and tea garden, and traditional lifting and handling equipment being difficult to apply and mainly relying on high intensity manpower, a swing arm loading and unloading structure for monorail conveyor is designed and optimized to meet the loading and unloading needs in hilly orchard and tea garden.

Method Based on the basic parameters of the electric monorail conveyor in hilly orchard and tea garden, a swing arm loading and unloading scheme was designed with the maximum loading and unloading height of 700 mm and the maximum loading and unloading mass of 200 kg. The motion and force of traditional swing arm loading and unloading structure were analysed, and a rope lifting arm linkage loading and unloading structure was designed through ADAMS parameterized modelling and optimization. Non-dominated sorting genetic algorithms Ⅱ(NSGA-II) was used for multi-objective optimization of the structural dimension. The dynamic simulation, prototype making, and load and swing test of rope linked loading and unloading structure were conducted.

Result The ADAMS parameterized modelling and optimization increased the loading and unloading range and reduced the required hydraulic cylinder driving tension for work. The maximum driving force decreased by 12.0% compared with the traditional swing arm loading and unloading structure. The theoretical maximum driving force was 5697 N and the maximum pulling force was 9 206 N after multi-objective optimization. Compared with the traditional swing arm loading and unloading structure, the theoretical maximum driving force reduced by 41.2%, the maximum pulling force reduced by 10.3% and the change rate of maximum pulling force reduced by 53.0%, which could avoid the sudden change range of oil cylinder load and make the load change curve smoother. The results of simulation and prototype tests showed the progressiveness and feasibility of the rope linkage handling structure.

Conclusion The designed and optimized swing arm loading and unloading structure can meet the loading and unloading needs of monorail conveyor in hilly orchard and tea garden, and can be applied and promoted in production practice of hilly and mountainous areas.