基于高速摄像技术的振动落果惯性力研究

Inertia force of fruits abscised by vibration based on high-speed video camera technology

【目的】研究果实在激振力作用下脱离枝干的运动规律、果实振动脱落时的加速度和脱落惯性力,为振动式果品收获机的研制提供理论依据。【方法】运用果树振动装置进行了杏果侧枝振动落果试验,采用高速摄像仪对分离过程进行了跟踪拍摄,通过Phantom控制软件对图像进行跟踪、捕捉、分析和计算,探寻杏果实在脱离枝干过程中瞬时速度的变化规律。【结果】杏果实脱离枝干过程中瞬时速度的变化表现为增大-减小-匀速运动-杏果实与枝干完全分离,杏果实与所在枝干的相对瞬时速度最大达到1.723m/s,杏果实的脱落加速度最大为4.270×102 m/s2,脱落惯性力最大为5.124N。【结论】脱落惯性力是杏果实脱离枝干所需的最小作用力,其是确定振动式果品收获机在收获果实的过程中作用于枝干激振力大小的理论依据,也是振动式果品收获机其他性能指标的理论参考。确定适当的激振力,可以保证振动式果品收获机在采收过程中果实的采净率高,同时对果树的损伤最小。

[Objective] The research studied the motion of fruits abscised by vibration force,and the acceleration and shedding inertial force of the fruits when dropping to improve the development of vibrating fruit harvester. [Method] We applied vibration device on fruit trees to abscise apricots from the lateral branches. High-speed video camera was used to track and screen apricots abscission process and Phantom control software was used to track, snap, analyze, and calculate the images. Based on these results the change rules of the instantaneous velocity of apricots abscising from branches was explored. [Result] In the process of apricots abscising from the branches, the instantaneous velocity increased first then decreased, then kept a uniform speed before abscising from branches completely. The maximum instantaneous velocity of apricots relative to the corresponding branches went up to 1. 723 m/s. The maximum abscission acceleration of apricots was 4. 270×102 m/s2 ,and the maximum shedding inertial force of apricots was 5. 124 N. [Conclusion] The shedding inertial force was the minimum force needed by apricots to abscise from the branches,and it played a critical role in determining the vibration force for vibrating fruit harvester. It was important to other performance parameters of vibrating fruit harvester. Determination of proper vibration force can ensure higher mining net rate and minimum damage to fruit trees in the harvesting process.