AutoV Corporation Sdn. Bhd. manufactures, assembles, and develops window regulator systems, wiper systems, sun visors, side mirrors, interior lamps, steering columns, and horns. It is a first-tier supplier to Proton, Perodua, Hyundai, Isuzu, Lotus, Toyota, Honda, and Naza as well as a second-tier supplier to APM and Delphi in Malaysia.
Endurance testing is extremely important in the automobile industry because it ascertains the life span of various components and parts under extreme conditions. It also confirms that a part, component, or system will perform well in a specific application. For power window regulator systems, 30,000 cycles of continuous operation is equivalent to its service life in a vehicle. At AutoV, endurance testing on window regulator assemblies is conducted frequently and upon the request of customers.
Prior to this, we used a traditional programmable logic controller (PLC) system to control only one test sequence. We conducted data logging separately using a state-of-the-art scope meter. The test supervisor then collated the data collected over 30,000 cycles and manually drafted a test report summary. The test sequence itself took about a week to complete, while the result collation and report summary took one to two days. Multiple tests usually required multiple PLC setups and multiple data collations. With the ever-growing demand for quality, the test system proved to be inefficient and time-consuming.
To test, monitor, acquire, and analyze data from multiple power windows at the same time, we used an NI cDAQ-9178 eight-slot chassis, an NI 9205 C Series analogue input module, an NI 9476 digital output module, and an NI 9425 digital input module. We used dedicated high-precision Hall effect current and voltage transducers to monitor the voltage and current of the power window motor in real time. With the user-friendly graphical programming of LabVIEW, blocks such as the DAQ Assistant made it easy to display these analog signals in real time while performing analysis in the background. We created alarms in case any of these values exceeded a specified range. We also used photo sensors to detect window glass up and down positions in the door assembly, and these signals were used to control a set of reversing contactors seamlessly via the digital output module. The reversing contactors control the up-and-down movements of the power window motor according to software timers created in the LabVIEW program. Due to the availability of analogue channels, we also incorporated temperature sensors into the test system to monitor real-time motor temperature.
With the above in place, we easily designed a graphical user interface to display key test parameters such as motor current, voltage, temperature, window travel time, and cycle count all in real time. Calculated test parameters such as average operation current, stall current, and travel speed were also displayed in real time due to the high processing power of the NI cDAQ-9178 device and the NI 3110 industrial PC. We easily achieved this with Express VIs such as the statistics and trigger blocks. We opted to use the fanless and rugged 1.6 GHz dual-core industrial PC so that the entire test system could be mounted in a single control panel, thereby eliminating the wiring problems usually associated with traditional PC-based systems.
Manually creating test reports for multiple power windows takes a lot of time and is prone to human error. With the LabVIEW Report Generation Toolkit for Microsoft Office, you can create and edit reports in Microsoft Word and Excel formats directly from LabVIEW. For this project, we created a custom report template in Microsoft Excel, and, once a specified number of cycles completes for a particular power window, a report summary is automatically generated in a specified folder on the industrial PC. We achieved this in a matter of seconds. External cooling of the power window motor is a normal practice during endurance testing to bypass the thermal circuit breaker embedded in the motor, which significantly slows down the test procedure. With the NI CompactDAQ device’s seamless communication between analog inputs and digital outputs via LabVIEW programming, the external cooling fan switches on automatically when a certain temperature is exceeded. This pushes the motor to its limit, which is the whole point of endurance testing.
The combination of the NI cDAQ-9178 and NI 3110 industrial PC offers a rugged yet extensive test platform for testing multiple power window regulators in parallel. It provides a versatile data acquisition system that delivers live data monitoring for every single test cycle. As such, the test supervisor can visualize the effects of other test conditions, such as run channel friction, on the motor’s performance. Future research and development on window regulator systems will be based on data collected from this piece of equipment. I would like to thank the sales and technical support team at NI Malaysia for its assistance during the course of this project.
Auto V Corporation Sdn. Bhd.