联合收割机制动系统虚拟样机仿真及试验

在农业机械产品快速设计系统中,农业车辆的制动性能应满足一定的安全技术标准,该文采用了一种基于虚拟样机技术研究联合收割机制动系统性能的方法,可为农机专业底盘制动系统的设计和性能评价提供参考。该文研究对象是前轮液压钳盘式制动系统,首先依据国产某型联合收割机参数,应用Pro/E建立整车及制动器三维模型,然后在此基础上导入ADAMS/View中建立整车和制动系统虚拟样机,并依据实测数据配置仿真模型属性,选定Ⅱ挡10 km/h、Ⅲ挡20 km/h 2种典型工况对虚拟样机进行制动性能仿真。对比硬路面条件下仿真和实车试验性能分析结果,踏板力实测95.6 N时,车辆III挡速度下,制动盘上接触力为4 272 N,制动距离为7.83 m,与踏板力为100 N时仿真结论(接触力为4 827 N和制动距离为7.398 m)较一致,表明该虚拟样机研究方法可行。

Simulation and experiment of virtual prototype braking system of combine harvester

Abstract: The brake system performance of an agricultural vehicle shall meet the technical safety standards. At present, the performance and reliability of the combine brake system in our country cannot fully meet the work requirements, and the studies about the braking performance of the combine are scarce. Virtual prototyping technology is an important process of Rapid Product Design (RPD), which has been gradually applied in the agricultural machinery industry. This paper presents a research method of the brake system performance based on virtual prototype technology.The front wheel hydraulic caliper disc brake system is debated, which was widely used in the self-propelled grain combine harvester. Firstly, the three-dimensional models of the vehicle and brake are established using Pro/E. The configuration setting of models come from a certain type of domestic combine harvester parameters. Then, the virtual prototypes of the vehicle and brake system are established in ADAMS/View. The configure parameters include the Fiala tire model, hard pavement, IMPACT function, and STEP input function, etc. The Kulun model was adopted by IMPACT function, and the pedal force data which comes from the experimental values was put into STEP function.Two typical working conditions of vehicle speed, II shift 10 km/h, III shift 20 km/h, are selected to simulate braking performance of the virtual prototype and real vehicle experiment. Simulated when III shift with the two kinds of pedal force, 100 and 200 N, the maximum contact force between brake disc and pad are 4 827 and 9 200 N. In the process of braking at the same speed, the contact force between the brake disc and the pad increases as the pedal force increases, and the increased tendency is accordant. By simulating the vehicle brake system, the maximum braking decelerations are 4.6 and 5.8 m/s2, braking distances are 2.3 and 1.49 m, when the pedal forces are 100 and 200 N with II shift speed. The maximum braking decelerations are 4.6 and 7.23 m/s2, braking distances are 7.398 and 7.004 m, when the pedal forces are 100 N and 200 N with III shift speed. In a certain gear speed, the greater the pedal force, the shorter the braking distance and braking time. At a certain pedal force, the higher the vehicle speed, the longer the braking distance and braking time.Mounted with a sensor and acquired by a measurement system, the data from the braking experiment which is composed of the displacement of the pedal, pressing of the left and right wheel cylinders, deceleration, and braking distance are analyzed with II shift and III shift speeds. The contact force between brake disc and pad is 4 272 N and the braking distance is 7.83 m when test with pedal force is 95.6 N, which is similar with results of simulation. Compared with simulation and a real vehicle test, both of the braking performance parameters are consistent. Between left and right braking are good synchronization; the response time is less than 0.6 s, the braking distance is less than 7.83 m, and the maximum braking deceleration is 2.43 m/s2 when pedal force is less than 100 N, which are in line with national standards on braking performance. The performance results verified the correctness of the virtual prototype simulation model of the combine brake system, providing an effective method for design and performance evaluation of agricultural machinery chassis braking systems.