Engine controller test system based on eCAR platform

The number and complexity of electronic systems in cars are growing. If the cost of electronic systems in the total cost of automobile production is taken as an indicator, by 2010, the share of electronic system costs in the total production cost has reached one-third, and this proportion is still increasing. At present, more than 90% of the innovations in new cars are based on electronic products, which enable automobile manufacturers to better meet customer requirements for high performance, comfort, communication and entertainment. In order to integrate these growing demands into today's electronic systems, today's cars have been equipped with a large number of sensors, actuators, control modules and distributed systems. Faced with this situation, automobile manufacturers need a complete set of test platforms to meet these ever-changing test requirements, and, due to product cycle considerations, the test platform must have higher test efficiency and flexibility.

In this context, Beijing Panhua Hengxing Technology Co., Ltd., based on more than ten years of experience in automotive electronics testing, launched a new automotive electronics testing platform, eCAR. This platform is a comprehensive testing platform developed for automotive electronics testing needs. Through scalable architecture and modular design, this platform can provide a series of solutions for automotive electronics testing and can be quickly transformed to complete new testing tasks.

eCAR ​​Platform

The eCAR automotive electronic test platform uses modular hardware and universal software. The platform can be divided into independent functional modules. The platform architecture is shown in Figure 1. The test platform has the following features:

Figure 1: Automotive electronics test platform architecture.

Open hybrid bus architecture: The test platform is based on the PXI platform, which can ensure the high efficiency of testing and control. At the same time, the platform integrates various communication buses such as Ethernet, GPIB, RS232, CAN, K-Line and FlexRay. This open hybrid bus architecture enables various instrument resources to be optimally used under this platform.

Test environment simulation technology: Accurately build a test environment from design to diagnosis. The test platform has strict stimulus response control, independent resources and parallel processing capabilities, and can meet the requirements of signal simulation and reliable measurement.

Efficient switch switching: The test platform can effectively monitor the working status of the pins of the device under test when connected to the load through the combination of programmable load and matrix. Complex tests can be completed efficiently through the cooperation of matrix units and measuring instruments.

Reliable general electrical system: The test platform uses a general electrical system to meet the requirements of automated testing of final inspection equipment on production lines. It has the capabilities of motion control of cylinders and motors, external status reading, and electrical safety control.

In order to meet the actual test requirements of different test projects, the eCAR automotive electronic test platform is equipped with different hardware components based on the general architecture to meet the needs of different test projects. The main hardware modules are listed below, and each type of module contains multiple models.

Rack: used to prevent measuring instruments and loads, etc. Power distribution: to provide power to the equipment. PXI chassis: used to install PXI controllers and PXI boards, with optional 8-slot, 14-slot or 18-slot chassis. Digital I/O: used to read and control switch quantities. Bus communication: bus communication with the device under test, with optional buses such as CAN, K-Line or Flexray. Analog I/O: The analog output part includes signal generation modules such as static analog output, PWM signal output, waveform generator and resistance signal output; the analog input part includes modules such as digital meters, multimeters and analog voltage acquisition. Switch module: including multiplexer switches and matrix switches, with optional RF switches, power switching switches or low-frequency signal switches according to the application. Load box: provides load for the device under test, with optional multi-channel loads and load parameters. General Electric: state input, used for signal input of proximity switches and optical sensors; execution output, used for control of pneumatic valve bodies and indicator lights, etc.; safety control, used for detection of states such as safety gratings and emergency stop buttons, as well as hardware-level response to power off and source, etc. Programming power supply: There are a variety of power supplies to choose from, depending on the power supply requirements of the device under test.

The software function module design of the eCAR automotive electronic test platform adopts the component-based and plug-in-based design concept, which basically covers all the functions of the final inspection test equipment of the production line, mainly including: Chinese and English interface, user management, parameter configuration, sample mode, product mode, engineer mode, database storage, report generation, data browsing and MSA analysis, etc. For different users, the test function can be conveniently selected, and it has the following characteristics: rich hardware driver library, configurable hardware resources, editable test process, professional test parameter algorithm set and optional test function, etc. The platform software has the following characteristics:

Customized test sequence/process: The ATLAS language parser of the eCAR automotive electronic test platform software can facilitate customers to complete customized test sequences/processes and improve the scalability of the test system.

Rich hardware driver and bus communication library: Considering that automotive electronic testing involves numerous devices and protocols, the automotive electronic testing platform software provides driver functions for today's mainstream instruments and supports customers' customized instrument drivers.

Industry expert algorithm library: For different types of applications, the platform software provides a professional industry expert algorithm library. Through a variety of signal analysis methods, combined with digital signal processing technology, the characteristics of the signal can be restored most realistically and the characteristics of the object under test can be characterized.

Interchangeable instrument technology and intelligent management of hardware resources: Considering the future upgrade and replacement needs of the test system, the test system software has good compatibility with various instruments. When the system needs to change the instrument model or even the supplier, the software platform can be changed seamlessly.

According to different automotive electronic product testing requirements, by selecting the corresponding hardware modules and reasonably matching the platform software, a new test system can be designed. The following case is designed based on the eCAR automotive electronic test platform. [page]

Engine controller LTT test system

The most complex electronic device in automotive electronic products is the engine controller. The functions of the engine controller include ignition control, fuel injection control, launch control, turbocharger-maintained boost level control, and other peripheral device control. To achieve these controls, a large number of sensor signals need to be collected, such as: MAP sensor signal, accelerator pedal sensor signal, throttle position sensor signal, oxygen sensor signal, and temperature sensor signal. Usually, the number of pins of the engine controller is between 100 and 200, which requires the test system to provide a variety of simulation signals, such as resistance signals, switch signals, PWM signals, sinusoidal signals, and static analog signals, and provide the controller with more than 30 load channels.

In addition, since the LTT (lift time test) of the engine controller requires uninterrupted operation for a long time (up to 24 days) in different environments (high temperature environment, low temperature environment, vibration environment and high humidity environment, etc.), the test system also needs to provide independent instrument resources, load resources and power supply system.

The eCAR automotive electronic test platform is used to build the engine controller LTT test system. The required modular hardware is shown in Table 1.

Table 1: Modular hardware of the engine controller LTT test system.

The test system block diagram is shown in Figure 2. The test system adopts a single host computer and multiple slave computers. The host computer is an industrial computer and the slave computer is a TestUnit. The industrial computer and the TestUnit are connected through a switch and communicate using the TCP/IP protocol. The TestUnit contains independent instrument resources, load resources, and power supply systems. Each TestUnit corresponds to an engine controller. Multiple TestUnits can work independently in parallel, corresponding to different test environments. The test system can be expanded to a maximum of 20 TestUnits (corresponding to 20 controllers) and tested in different environments at the same time.

Figure 2: Block diagram of the engine controller LTT test system.

The system block diagram of TestUnit is shown in Figure 3, and its appearance is shown in Figure 4. TestUnit has the following features:

Figure 3: TestUnit block diagram.

Figure 4: TestUnit appearance.

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Rich instrument resources: including 110 digital I/O channels, 32 16-bit analog input channels (sharing 250kS/s sampling rate), and 4 16-bit analog output channels.

Powerful communication capabilities: high-speed (1Mbit/s) CAN bus, K-Line bus, scalable LIN, Flexray bus.

Up to 64 programmable analog load channels.

Quick connection: Connection to the engine controller is via a 150-pin Harting connector.

Convenient debugging interface: Auxiliary Harting interface, used to manually monitor the instrument working status during the test process.

The plug-in modular design is convenient for maintenance and upgrade. When the model of the engine controller changes, resulting in changes in the pin definition and test environment, there is no need to replace the expensive instrument resources of the TestUnit. You only need to selectively replace the programming resistor card, signal conditioning card, analog load card and switch card.

The appearance of the engine controller LTT test system is shown in Figure 5 (using a 42U standard cabinet). The software of the engine controller LTT test system is built using the software of the eCAR automotive electronic test platform, and the main interface of the software is shown in Figure 6. The test system software includes basic functions in the eCAR platform software such as custom test sequences/processes, instrument management, bus communication, and expert algorithm library.

Figure 5: Appearance of the engine controller LTT test system.

Figure 6: Main interface of the software.

Conclusion

The test requirements for automotive electronic products are transitioning from simple pass/fail to multiple performance index tests. In response to these changes in requirements, the eCAR platform can provide a standard, flexible hardware configuration and portable software platform for automotive electronic product testing, thus providing an efficient solution.