5个测试步骤, 一个方案: 采用 FASTpress 对复杂的转向系统的最终检查
现代车辆的转向系统有负载的功能 – 因此在驾驶和安全性方面有重要的影响.
转向系统的装配和测试的要求非常高 –这些系统包含很多机械和电子元件 需要被连接，装配和测试 单个元件的测试都非常重要，更何况是整个系统的装配? 工业过程控制器 MP85A FASTpress 可为复杂且安全性高的车辆系统的装配提供高效，且安全性高的解决方案.并保证对测量结果完全记录
转向系统的检查 包括不同的测试步骤，不同的测量参数都需要进行分析。因此需要完整的系统来比较所有的测量数据和参数进行监控. 通过过程控制器 MP85A FASTpress 和i FASTpress Suite 软件可以完成.
领先的系统集成商采用 MP85A FASTpress 成功地完成了转向系统的测试. 当转向系统转配完成后，过程监控便开始了. FASTpress 控制以下步骤:
- 感觉特性曲线
- 阀门曲线
- 位移，力
- 扭矩
- 进行测量
即使这些测试任务是不同的，但都有共同的特点: 每个测试步骤都评估曲线形式和位置, 并精确定义容差限制. 更进一步是获取，存储统计数据: 例如：最大最小值，平均值，目标/实际偏差等.
每个测试步骤的过程控制器通过以太网连接. 所有数据可以存储在共同的目标盘中. 每个转向系统都有自己的识别号. 这些过程数据，以及相关的特性都可以容易获得.
这些是不同的测试步骤:
感觉特性曲线和阀门曲线：: Is the feel of the ride correct?
驾驶和安全感觉受到转向系统的影响很大. 转向必须要对驾驶者期望的方式做出反应..
In all these perceived steering characteristics of a vehicle, the feeling characteristic curve plays a decisive role. By changes in the feeling characteristic curve, the behavior of the steering can be influenced in the factory. Possible settings, for example, can be "Comfort" or "Sporty". The reset torque in the steering wheel changes according to the driving characteristic.
To check the feeling characteristic curve, the connecting rod is fixed and equipped with a force transducer to measure the tensile and compressive forces. A power shaft then applies a torque to the steering column. The evaluation algorithms in MP85A FASTpress and the corresponding parameter sets enable the simulation and individual setting of the reaction behavior of the steering for various speeds.
The valve curve must also be checked for setting the feeling characteristic curve. This means that The pressure of the hydraulic system is monitored on the basis of the applied torque so that the curve must follow a predefined form.
In this operating mode, the sequence of evaluation windows is significant as the curve consists of a rising and falling branch. Thanks to the special window technology, the FASTpress monitoring criteria differentiates between these sequences. FASTpress only activates the falling branch for monitoring once the curve has reached its maximum.
Further steering system tests
Measuring the displacement force: A numerically controlled machine axis (NC axis) applies the displacement force to the connecting rod for this test step. The displacement itself is also recorded by the absolute value encoder of the NC axis. The test here is passed when the curve trace does not exceed specific min/max limits in both tensile and compressive directions and the maximum deviation from the mean value is sufficiently small.
Torque testing: In the torque test, a rotary motion is applied via the steering column. The friction moment is recorded and monitoring according to the same criteria used for the displacement force for peak and mean values.
Play measurement: The setting of the play between steering column and connecting rod must be separately tested and set. This is essential for the stiffness of the transmission elements pinion and gear racks. The NC axes also applies a rotary motion to the steering column for this test. The position of the thrust piece on the gear rack is measured with a separate displacement probe and set symmetrically to the mean/comfort position in the setpoint.
Evaluation and data backup: An integrated system for secure process monitoring
The secure acquisition of measurement parameters is just one aspect in process monitoring. Just as essential for the security and efficiency of test procedures are the statistical tools of the checking software.
The FASTpress software suite has the perfect requirements for this – even and specifically for the testing of steering systems: Firstly, the FASTpress software suite collects statistical facts from the data in a pilot series. These data then flow as evaluation limits for the mass production series later on.
This upstream process data analysis with statistical evaluation using the "EASYteach" software module facilitates the identification of relevant evaluation criteria – and does this in just a few steps:
- First of all the required number of processes are recorded with the monitoring software PME Assistant
- The data series obtained here are read into the EASYteach module of the PME Assistant and are available graphically both as curve family and mean value curve
- After the curves are processed (e.g. edited, deleted), they can be aligned relative to each other. It is also possible to print or save evaluation windows and outline parameters in a report
- Finally, the evaluation windows or tolerance ranges can be loaded back into the MP85A FASTpress process controller.
This procedure provides an integrated system for process monitoring: From measurement of the release sample to continuous process monitoring during ongoing production to determination of reproducible evaluation parameters.
Simple individualization possible
In the application case described here, the central visualization and control of all process parameters is implemented via a Siemens MP277 Panel directly at the test cell. In addition to the visualization of the entire system, the Siemens Panel also displays the process monitoring data acquired by the MP85A FASTpress.
Depending on the application, the FASTpress software also enables the development of customized views with the .net class library. Individually tailored display windows and a clearly structured process depiction are therefore available to the users. These individual views can be programmed directly by HBM – or by each user themselves (e.g. in C#, VB.net and all other .net-compatible programming languages).
Special displays are not even required for these individual presentations. Thanks to the open structure of the FASTpress suite, the process monitoring data can also be displayed using the human-machine interfaces (HMI) – in this case, the Siemens MP277 – in general use or standard industrial PCs (IPCs).
FASTpress: Integrated for more security
The industrial process controller MP85A FASTpress and the matching FASTpress software suite form the best basis for integrated process monitoring – even then when the requirements regarding monitoring, data backup and integration are extremely high. This applies in particular to safety-relevant components such as steering systems.
The perfect interplay of hardware and software allows, for instance, system builders to simply plan the overall system, including control and monitoring elements (as here for the steering tests). Users of the process monitoring system profit from the high integration level and the simple, transparent operation of the control system.
