【作者】 陈峰；

【导师】 黄志坚；

【作者基本信息】 广东工业大学 ， 机械电子工程， 2007， 硕士

【摘要】 本课题是在现有的汽车制动软管爆裂试验台的基础上，采用计算机技术对其控制系统进行改进。改造前的试验台检测时，操作者通过边观察显示仪表上的读数，边用手调节加载阀，对试件进行加压。这种操作精度很低，并且检测时，因加载阀的压差较大，且手动操作不稳定，使得加压速度很不稳定，容易引起压力陡升，造成检测的失败。本课题采用手动阀与步进电机相结合的方式，把加载阀改造为数字阀。改造后的数字阀用PLC来控制，通过控制阀的开口量，从而控制加压速度。为了解决步进电机的扭矩不够大和步距角太大的问题，在手动阀与步进电机之间连接一个减速器。并利用步进电机的驱动器的细分功能，进一步细分步进电机的步距角，使数字阀理论上每脉冲转动角度变得非常小，以提高系统的控制能力。在控制策略上，采用模糊控制，模拟人的操作过程。控制规则根据操作经验来确定。先离线计算出模糊控制查询表，然后利用间接地址查表的方法，在西门子S7-200 PLC上编程实现模糊控制算法。本课题采用PLC作为下位机，实现控制系统的控制功能。PC机作为上位机，存储和查看检测结果和相关数据。用WinCC作为组态软件，编写上位机的监控画面。用VB编写软件，处理数据库中压缩的历史归档数据。实例和数据证明试验台控制系统的改进基本上达到了预期的目标。更多还原

【Abstract】 This subject improves control system of test bench that is used to test burst property brake hose of automobile.Before the test bench hasn’t been improved, operator add pressure to brake hose by handing regulate pressure-biased valve according to the display of instrument. The accuracy of test is very low. Because the pressure difference of pressure-biased valve is very high in the test and the unsteadiness of hand operation, the pressing speed of brake hose is unequable, and the pressure will tend to appear steep ascent, which make test failure. This subject improve pressure-biased valve to digital valve which is associated by throttle and step motor. The digital valve is controlled by PLC. The pressure speed is controlled by auto-regulate valve opening size. In order to solve the problem that torque of step motor is too small and the stepping angle of step motor is too big, gearbox is used to associate step motor and valve. The stepping angle is further subdivided by use the function of step motor driver’s subdivision, which make the angle of every pulse very small in theory, which improve the accuracy of control system.Fuzzy control strategy is used to simulate man operate process. Control rules are determined by operational experience. Firstly, the query table of test bench fuzzy control quantity is calculated by off-line. Then, fuzzy control strategy is realized in PLC program by use lookup table of indirect address.Control function of test bench is realized by slave computer-PLC. The host computer is PC, which save and view test result and data. The monitoring and control interface in host computer is established by WinCC. The interface written by VB is used to manage compressed archived data in database.Finally, according to the test result, the improvement of test bench control system is successful basically.更多还原