06. December 2016 Technology

Testing complex vehicles

More ECUs, more variants, ever-increasing interconnectedness - this is how automobile manufacturers can safeguard complexity.

In the automotive sector, innovations are increasingly taking place in the field of electronics and software. Current vehicle models accommodate a large number of software-supported electronic systems interlinked with each other. This development has led to the fact that both the production costs and the development costs of automobiles are increasingly determined by electronics and software.

For the future, too, there is no end in sight to this development. The vehicle is gradually becoming a rolling computer: Features such as semi-automated or autonomous driving, the integration of the vehicle with the Internet of Things or the integration of mobile devices require more and more software in the car. The number of control devices in the vehicle continues to rise - the entire vehicle is becoming ever more complex.

Reasons for the increase in testing effort

This complex system must be tested in order to avoid any errors for the customer. In vehicle development, the number of software versions that have to be tested is increasing. In order to be able to carry out a test on the test bench or test vehicle intended for this purpose, a number of criteria must be taken into account. Three examples:

  • Country variant: Vehicles in different countries have to comply with different legal requirements - for example, different regulations for lights and indicators. This often requires country-specific behaviour of the corresponding control unit, which must be differentiated accordingly in the tests.

  • Engine variant: The engine variant (petrol, diesel, hybrid, electric drive) and its power output level influence many different functions in the vehicle. Different tests must therefore be carried out depending on the engine variant.

  • Configuration: The vehicle configurators offer the customer hundreds of possible optional extras. Depending on the selected equipment, more or less ECUs are installed in the vehicle. In addition, individual control units may be available in different versions (for example, the low, mid or high versions of an infotainment system). The possible variations must be taken into account during the test execution.

Countless vehicle variants - how to test?

Due to the large number of possible combinations, there are many possible variants of a single vehicle model. Automobile manufacturers are faced with the challenge of testing all conceivable variants of a vehicle. However, covering this variety of variants with a test fleet and manual testing leads to skyrocketing costs. Therefore, technical solutions to increase test capacity while maintaining acceptable costs are essential.

This problem is exacerbated by the fact that the time to market must also be shortened in automotive development, for which an increase in efficiency in the area of vehicle software development is indispensable. To this end, attempts are being made to follow the path of agile software development and to focus on continuous integration, which will further increase the number of test cases to be performed.

The above reasons lead to the fact that the automobile manufacturers increasingly rely on carrying out this huge number of test cases on test benches. The great advantage of a test bench over a prototype vehicle, for example, is that a specially adapted test bench is noticeably cheaper. On the other hand, a test bench offers the possibility to have test cases performed automatically, i.e. without direct human input - also at night and during weekends. These solutions for test automation enable a significantly higher test width and depth compared to manual testing in order to get the above-mentioned multiplication of test cases under control.

Automatically change variants on the test bench

In order to cover the variety of different control unit variants on the test bench, however, a modification has so far also been necessary on the test bench: one control unit has to be disconnected, the other has to be plugged in. If this conversion occurs outside working hours, e.g. at night or on weekends, the test bench stands still and valuable test bench time is lost.

However, intelligent solutions also automate this process: With the in-tech orangeSwitch, various hardware variants of an ECU can be connected to an electronic test bench (component or system HiL). The change between the variants then takes place automatically via test automation.

This means that different hardware variants of an ECU can be tested automatically one after the other and optimum test stand utilisation is achieved without any maintenance or conversion work. Due to the high scalability, as many variants as desired can be tested and due to the high level of automation, the entire test sequences are optimized.

Use of new test bench technologies

More complex tests as well as a strongly increasing number of tests require a rethinking in test bench development. In the test phase of electric and hybrid vehicles, for example, high-voltage components and low-voltage components have to be tested spatially separately. This is not possible with standard test benches in 19-inch industrial racks. in-tech has developed the modular orangeHiL for this purpose, which enables all test stand connections via standard LAN cables. The so-called EtherCat® protocol is used to guarantee real-time performance. This makes it possible to test spatially distributed vehicle components together on one and the same test bench. The existing house network can even be used for this purpose.

Efficient testing and measuring via app

Live display of any vehicle status or bus signals: orangeCtrl, developed by in-tech, enables frequently required vehicle diagnostic commands to be sent and analyzed with a single click via the mobile app, while the compact hardware accesses the vehicle via the CAN, Flexray and Ethernet interfaces. The tester can thus already check during the test whether all general conditions for his test are correct. This greatly reduces time-consuming repetitions and subsequent data analyses. Intelligent energy management ensures low power consumption and ultra-mobile application options, making it the ideal solution for use in test vehicles.

The use of orangeCtrl also increases efficiency on the test bench. The ability to switch between vehicle states with just one click saves a lot of time. The orangeCtrl also offers room for expansion, since a fully-fledged Mini-PC with a complete Linux operating system is installed and the CAN interfaces can be easily accessed via the widely used socketCAN system. New applications and test scripts are therefore quickly implemented.