基于虚拟样机的桁架式喷洒车稳定性动力学仿真

为了提高卷盘式喷灌机桁架式喷洒车爬坡和抗倾覆能力,克服喷洒车试验周期长、成本高、试验优化能力受限制的缺点,采用虚拟样机软件ADAMS建立JP75型喷灌机桁架式喷洒车的动力学参数化仿真模型,对喷洒车的纵向、横向抗倾覆性以及爬坡能力进行了仿真。分析了不同坡度角工况下影响桁架式喷洒车爬坡和抗倾覆能力的几种关键因素,采用二分法控制仿真坡度角的变化,对各因素的影响程度进行了仿真试验研究,提高了仿真速度。通过对影响爬坡和倾覆性能较大的地面粘附系数、质心高度、轮距等关键因素进行优化,使临界爬坡角比现有喷洒车提高了21.48%。优化后新机型的试验运行结果表明,在同样坡度工况下新机型倾覆次数明显减少,能够达到的最大爬坡角得到提高,仿真优化取得明显效果。

Dynamics Simulation of Stability of Spraying Vehicles Based on Virtual Prototype

Truss type sprinkler cart is one of the main parts of traveller irrigation machine, which plays an important role in modern agricultural irrigation. However, the sprinkler cart may get overturned or broken in the fields because of its large spraying arm span, unreasonable span setting between wheels and/or excessive moisture of the fields. Thus, a parameterized dynamics simulation model was established for type JP75 sprinkler cart in the software ADAMS to improve its abilities of slope climbing and anti overturning. Qualitative performances of the sprinkler cart were analyzed based on the proposed model. The slope angle was taken as an evaluation index of slope climbing and anti overturning abilities. Several key factors affecting the climbing abilities greatly were optimized, such as attachment coefficient, wheel spacing and centroid height. The bisection method was firstly brought into the simulation of sprinkler cart to accelerate the algorithm convergence. Compared with the current machine, simulation results show that the optimized sprinkler cart improves its stability by increasing the slope angle with 21.48%. Moreover, a physical prototype was developed and a field test was conducted to confirm both the accuracy of the simulation and the validity of the methods adopted. Test results show that both the number of overturn and torsion extent of the cart were decreased greatly with the water distribution uniformity increased dramatically. The abilities of slope climbing and anti overturning of truss type sprinkler cart were improved significantly. This paper provides a new method for the design of truss type sprinkler cart.