曳引摇枝式板栗落果装置设计与试验

针对当前丘陵山地板栗采摘困难、人工收获工作强度大、采收效率低等问题，设计了一种由柔性钢丝绳曳引振动的小型摇枝式板栗落果装置。建立板栗果实-果枝单摆动力学模型，分析果实脱落条件，得到板栗果实振动脱落切向加速度为285.36m/s2，得出影响板栗果实脱落的主要因素为果枝振动频率、振幅、振动时间；进行板栗果枝振动特性试验，用Default Shaker液压振动台以0~30Hz扫频方式确定垂直方向上板栗果枝共振频率，并在频率7~15Hz段进行驻频试验，得出振动落果较优频率为10~12Hz。根据果枝振动试验结果，利用ADAMS软件对摇振机构进行仿真，结果表明，摇杆振幅大于95mm时，果枝末端加速度可满足板栗果振动脱落的加速度条件，确定了落果装置参数设计的合理性。设计了三因素三水平正交试验，试验结果表明，板栗落果最佳作业参数组合为摇振频率11Hz、振幅135mm、摇振时间30s，此时板栗落果率为91.9%，树皮损伤率为8.8%，满足农业机械推广鉴定标准中树皮损伤标准。

Design and Experiment of Trolling Branch-type Chestnut Fruit Dropping Device

In view of the difficulties in picking chestnuts in hilly areas, the high intensity of manual harvesting and the low efficiency of harvesting, a small shaking branch type chestnuts dropping device with the vibration of flexible wire rope was designed. A single pendulum model was established to analyze the conditions of fruit shedding. The tangential acceleration of fruit shedding was 285.36m/s2, and the main factors affecting fruit shedding were the frequency, amplitude and time of branch vibration. The vibration characteristics of chestnut fruit branches were tested. The frequency range of chestnut fruit branches in the vertical direction was determined by sweeping frequency mode of 0~30Hz with Default Shaker hydraulic shaking table, and the standing frequency test was carried out in the frequency range of 7~15Hz. The optimal frequency range of vibrating fruit fell was found to be 10~12Hz. According to the results of the fruit branch vibration test, ADAMS was used to simulate the shaking mechanism. The results showed that when the rocker amplitude was greater than 95mm, the acceleration of the end of the fruit branch could meet the acceleration conditions of the chestnut fruit vibration, and the rationality of the parameter design of the fruit dropping device was confirmed. A three-factor and three-level field orthogonal test was designed, and the results showed that the highest fruit drop rate was the shaking frequency of 11Hz, the amplitude of 135mm, and the shaking time of 30s. In the experiment, the highest fruit dropping rate of chestnut was 91.9%, and the bark damage rate was 8.8%, which met the bark damage standard of agricultural machinery popularization and identification.