基于参数化模型的零转弯半径割草机侧翻稳定性

Rollover stability of zero turning radius lawn mower based on parametric model

针对近年来零转弯半径(ZTR)割草机在横向坡道上频发的侧翻安全事故,基于准静态动力学理论,建立了一种坡道工况下能预测分析ZTR割草机失稳的参数化力学模型。根据割草机实际工作状态,加入了驾驶员因素以及不同规格割具在悬挂、牵引状态下对整车侧翻稳定性的影响。利用Matlab求解了理论侧翻预测方程,分析了不同工况下割草机横向载荷转移率与其侧翻敏感参数之间的关系,并利用ADAMS对割草机进行了多组仿真实验,进一步验证了参数化模型的准确性。通常,割草机底部配备悬挂割具可降低整车质心高度从而增强坡道稳定性。但通过实验发现,割草机底部配备牵引式割具比配备悬挂式割具的抗侧翻性能更强:其中配备1.2 m和1.8 m规格悬挂式割具的临界侧翻角较裸车分别提升了7%和10%;而配备1.2 m和1.8 m规格牵引式割具的整车临界侧翻角较裸车分别提升了9%和21%。根据这一特性,建议在设计农用或园林车辆的工作器械时优先考虑底部中置牵引结构,以提高各类车辆在斜坡上工作的安全性。

In response to frequent rollover safety accidents on the transverse slope of the zero turning radius lawnmower in recent years,based on the quasi-static dynamics theory,a parametric mechanical model that can predict and analyze the instability of the ZTR lawn mower under ramp conditions is established.According to the actual working state of the mower,the driver factor and the influence of different specifications of cutting tools on the vehicle rollover stability under the suspension and traction state are added. The theoretical rollover prediction equation was solved using Matlab,and the relationship between the lateral load transfer rate of the lawnmower(M-LTR) and its rollover sensitive parameters was analyzed under different working conditions. Using ADAMS to conduct multiple sets of simulation experiments on the lawnmower, further verify the accuracy of the parameterized model. Through experiments,it is found that the traction cutter at the bottom of the lawn mower has stronger anti-rollover performance than the suspension cutter:the critical roll angle of the 1.2 m and 1.8 m suspension cutters is increased compared with the bare car about 7% and 10%;with 1.2 m and 1.8 m and specifications of the vehicle with traction cutting the critical roll angle are improved compared with naked car about 9% and21%. According to this characteristic,it is recommended that when designing working instruments for agricultural or garden vehicles,priority is given to the bottom center traction structure to improve the safety of various vehicles working on slopes.