Design and experiment of wine grapes cold-proof cover rolling and laying integrated machine based on RecurDyn/MTT3D

In northern China's open-field grape cultivation areas, the cold and dry winter climate poses severe threats of freezing damage and even death to grapevines. To ensure the quality and yield of grapes in the following year, it is essential to prune and lay down the vines before winter and adopt appropriate cold protection measures. Among various cold protection methods, using cold-proof covers has been widely adopted due to its advantages of moisture retention, thermal insulation, reusability, and effective prevention of sandstorms, making it a low-cost and efficient measure for sand control. However, the current laying and rolling operations of cold-proof covers are entirely manual. Aiming at the problems of low operation efficiency and high labor intensity in the spring rolling and winter laying of cold-proof covers in cold-proof areas, a multifunctional integrated machine for rolling and laying cold-proof covers was designed in this study. The machine was mainly composed of a main frame, an auxiliary frame, a hydraulic system, a winding core, a cover spreading frame and other components. The whole machine was connected to the rear of a tractor by means of the three-point suspension method, and the high-efficiency rolling of the cold-proof cover was realized through the reverse forward rolling mode; during laying, the self-weight of the cold-proof cover drove the winding core to rotate so as to achieve automatic laying. A flexible media model of the cold-proof cover was established based on RecurDyn/MTT3D (Media Transport Toolkit 3D), and the modeling parameters of the cold-proof cover were calibrated by simulation. The generation mechanism of wrinkles during the rolling process of the cold-proof cover was analyzed through simulation and theoretical research, and an auxiliary flattening scheme with the cover spreading frame was proposed. Taking the height of the winding core from the ground, the depression angle and the flattening angle of the cover spreading frame as experimental factors, the Box-Behnken experimental design method was adopted for parameter optimization, and the optimal operation parameters were obtained as follows: the height of the winding core from the ground was 1400 mm, the depression angle of the cover spreading frame was 10°, and the flattening angle was 120°. Under the optimal parameters, the simulated theoretical flattening rate reached 98.2% with a traction resistance of 335.7 N. A prototype was manufactured and field experiments were carried out for verification. The field test results showed that the cold-proof cover was effectively spread to both sides under the action of the cover spreading frame, and could be rolled on the winding core relatively flatly by the winding core. The actual flattening rate was 97.6%, with an error of only 0.6% compared with the simulation result. The rolling efficiency of the machine was 21.1 seconds per cover and the laying efficiency was 16 seconds per cover. The research results indicated that the designed machine could meet the operational requirements of rolling and laying cold-proof covers for grapes in northern China. The research findings offer technical references for subsequent studies on cold-proof cover rolling and laying machinery.