基于PLC的橡胶树皮非线性力学性能探测装置设计与试验

Design and Test of Nonlinear Mechanical Properties Detection Device of Rubber Bark Based on PLC

为了获取橡胶树皮结构力学特性参数,解决机械化采胶装备研发中采胶深度精准探测和耗皮厚度精准控制技术无可靠依据提供参考的问题,设计一种基于可编程序逻辑控制器(programmable logic controller, PLC)的橡胶树皮非线性力学性能测量的试验装置,实现橡胶树皮力学特性的自动化连续探测和数据采集,以及树皮厚度的高精低损测量。并应用于热研7-33-97和PR107两个品系的15龄、20龄、25龄橡胶树上进行树皮力学性能试验研究,建立刺入过程中刺入力随刺入深度变化的数学模型。结果表明:该装置工作性能稳定,不同品系、不同树龄的树皮刺入力随刺入深度的变化曲线形态相近,均呈高-低-高的趋势变化,并与树皮结构分层特性高度相关;相同树龄下,热研7-33-97和PR107两个品系的刺入力情况差异不明显,同品系的大树龄比小树龄刺入力更大,在1.0 mm针刺下,刺入力最大峰值可达48.5 N。该试验装置满足橡胶树皮结构力学特性参数的探测需求,并为机械化采胶装备的研发提供理论基础。

In order to obtain the structural mechanical property parameters of rubber bark and solve the problem that there is no reliable reference for accurate detection of rubber depth and accurate control of skin loss thickness in the research and development of mechanized rubber picking equipment,a test device for nonlinear mechanical property measurement of rubber bark based on PLC was designed to realize automatic continuous detection and data collection of rubber bark mechanical properties with high precision and low loss measurement of bark thickness.The mechanical properties of bark of 15-,20-and 25-year-old rubber trees of Reyan 7-33-97 and PR107 were studied,and the mathe-matical model of piercing force with piercing depth was established.The experimental results showed that the perform-ance of the device was stable,and the piercing force curves of different strains and different ages were similar,showing a high-low-high trend,and were highly correlated with the layered characteristics of the bark structure.Under the same age,the piercing force of two strains of Reyan 7-33-97 and PR107 was not significantly different,and the piercing force of older trees of the same strain was greater than that of younger trees.The maximum piercing force reached 48.5 N.The test device meets the requirement of detecting structural mechanical parameters of rubber bark and provides theo-retical basis for the research and development of mechanized rubber harvesting equipment.