基于准零刚度的微耕机把手隔振系统设计与试验

Design and Test of Vibration Isolation System for Microtiller Handles Based on Quasi-zero Stiffness

摘要:

针对丘陵地区电动微耕机作业时低频振动过强易引发操作者健康问题的现状,提出基于准零刚度原理的并联式非线性隔振系统的设计方法。首先,该系统通过负刚度机构与线性弹簧并联耦合实现高静低动,并确立负刚度结构的初始挠度q0、初始倾斜角θ(0°~26.6°)及刚度比λ为核心设计参数;其次,建立隔振系统静力学模型,分析其高静低动特性,最后开展振动台架试验验证系统性能。为设计并验证隔振结构的性能,本文于田间测试了微耕机的振动特性,结果表明,快挡作业下振动强度、振动幅值由刀辊经底盘与扶手架连接处到扶手处逐渐升高,X、Y、Z方向振动强度从4.14、4.95、5.56 m/s2增加到6.14、7.16、8.48 m/s2,各工况下扶手处Z方向的振动强度最大。静力学试验表明,加载/卸载路径最大力偏差为2.349 N,占理论值的14.68%。振动台架试验结果表明,在试验的激励范围(1.5~12 Hz)内准零刚度隔振系统的传递率下降82%。本文设计的把手隔振系统具备低频隔振性能优异的特点,可为电动农业机械减振设计与人体工效优化提供参考。

Abstract:

Aiming to address the health risks posed by excessive low-frequency vibrations during electric micro-tillers’ operation in hilly regions in South China, a design methodology for a parallel nonlinear vibration isolation system was proposed based on the quasi-zero stiffness principle. Firstly, the system achieved high static stiffness and low dynamic stiffness through parallel coupling of a negative stiffness mechanism with linear springs. Key design parameters, including the initial deflection q0, initial tilt angle θ (0°~26.6°), and stiffness ratio λ of the negative stiffness structure were established. Secondly, a static model of the isolation system was established to analyze its high-static-low-dynamic stiffness characteristics. Finally, vibration test bench experiments validated the system performance. To design and verify the isolation structure’s performance, the vibration characteristics of a micro-tiller were tested in the field. Results indicated that during high-speed operation, vibration intensity and amplitude progressively increased from the cutter bar through the chassis connection point to the handlebar, with vibration intensities in the X, Y, and Z directions increasing from 4.14 m/s2, 4.95 m/s2, and 5.56 m/s2 to 6.14 m/s2, 7.16 m/s2, and 8.48 m/s2, respectively. The Z-direction vibration intensity at the handlebar was the highest under all operating conditions. Static tests revealed a maximum force deviation of 2.349 N during loading/unloading paths, accounting for 14.68% of the theoretical value. Vibration test results demonstrated an 82% reduction in transmission rate for the quasi-zero stiffness isolation system within the tested excitation range of 1.5 Hz to 12 Hz. The handle vibration isolation system designed exhibited outstanding low-frequency isolation performance, providing technical support for vibration reduction design and ergonomic optimization in electric agricultural machinery.