Design on key parts of cable-driven hanging transportation system for orchard

Abstract: The majority of domestic orchards have poor site conditions. It is difficult for the traditional wheeled or crawler transport machinery to carry out operations in hilly orchards. The cargo transportation is mainly done by manpower, which is labor-intensive, has low efficiency, easy damage of the fruit and high cost. In order to solve these problems in hilly orchards, a cable-driven hanging transportation system for orchards was designed. Based on the technical requirements of two-way traction, turning during climbing and derailment prevention, the structure of the key parts of the system was designed. This mainly included the cable hoist, a pulley-hook group, a cable frame, a double rail, supporting and turning mechanism, a tension mechanism and a limit switch. The stability and security of this system has been tested through measuring the braking distance after the head pulley group collided with the limit switch installed on the supporting pipe. The results indicate that the braking distance is unrelated to the load weight. The mathematical model of the rope tension under the complicated condition is proposed, along with considering the climbing angle, number of supporting and turning mechanisms, turning angle, load weight, initial tension and friction coefficients. The experiments were conducted on the system built at South China Agricultural University. The mathematical model for the cable tension of the experimental system is F=11.4m+587. By detecting the force on the guiding mechanism and the turning angle with sensors, the tension force will be obtained. The linear regression equation calculated from the experimental data is F=11.95m+554. The coefficients of the regression equation obtained from the single-factor experiment are close to those of the mathematical model, which illustrates that the proposed model can reflect the variations of the rope tension. The results of this paper can provide a reference for the power selection and the structure parameter matching of the system. The 7YGQX-5.5 type cable-driven hanging transportation system for orchards has been applied in the Dongguan Agricultural Science Research Center, which has proven to be easily manufactured and constructed, economical and highly efficient. The system can realize both remote control and convey bananas or other fruits without damage.