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Embedded system enables mobile data transfer from cars

by Heiko Krautter | Jan 27, 2015

Advantage of the latest tire technology experienced in self-test

Conticabana driving event

Image 1: Approximately 2300 international guests experienced the impact of the tire pressure on the driving stability of vehicles during the Conticabana driving event.  

 

Approximately 2,300 participants from the press, OEMs and tire dealers participated in a several weeks long event around the topic vehicle dynamics measurements, organized by Continental Reifen Deutschland GmbH. In different test series the behavior of modern tire design was analyzed. Self practice is a good basis for knowledge transfer. In this way, Continental wanted to impart the latest insights regarding the performance of modern tires to representatives of the press and decision makers from the industry. At the driving station “Under Pressure” loss of cargo from a vehicle in front was simulated and braking and swerving actions of guests (Image 1) at different tire pressures was measured and recorded. These car dynamics measurement data were transmitted from the test car via telemetry and analyzed online. Finally, a vehicle dynamics simulation, parameterized by means of the measurement data, allowed the individual guest to understand the physical basic principles. By means of this visualization it was possible to project complex dynamic stability analyses in the context of own experienced vehicle responses.

Presentation of the measuring instrumentation  

Image 2: This image shows the presentation of the measuring instrumentation for recording the vehicle movement data in the boot, which were transmitted by means of the telemetry system to the analysis room.

Vehicle dynamics engineer Christian Cramer analyzes the driving maneuvers 

Image 3: Vehicle dynamics engineer Christian Cramer analyzes the driving maneuvers of the guest by means of online measurement data parametrized from a driving dynamics simulation model.

Sophisticated test conditions

Preparations and event (Image 2) were carried out under supervision of Nels von Schnakenburg, Section Manager Technical Event Management at Continental. (Image 3) Christian Cramer from the group Test Method Development & Vehicle Dynamics developed and controlled the driving station “Under Pressure” (Image 4). Both explain the requirements profile like this: “The realistic test could only be properly visualized with an optimal data basis. Based on previous tests we selected a suitable vehicle for this test, a medium-sized sedan with excellent handling dynamics. To analyze every individual test drive, internal sensor signals for mapping vehicle dynamics data were read out, transmitted and visualized from the test drives at the events. In this way, during highly dynamic maneuvers at the limit the impact of low tire pressure could be depicted. Both the load of the tire contact area and the different vehicle responses could be respectively visualized with the measurement-based vehicle dynamics simulation. (Image 5).”

Welcome at the conticabana driving event  

Image 4: Nels von Schnakenburg, Section Manager Technical Event Management of Continental Reifen Deutschland GmbH, greets the customers at the driving event “Conticabana”.

If for previous test runs often external measuring instruments such as the Peiseler wheel were used, then today many data can be directly read out from the on-board bus system from existing sensors. After all, measurement data for ABS, ESP, traction control, etc. are constantly recorded and transmitted. As an alternative for recording the data directly in the vehicle also the use of a special measuring steering wheel could have been considered. But this was not available in sufficient number and also showed haptic disadvantages compared to the serial steering wheel, which would have impacted on the test practicability.

Bild5 

Image 5: This image shows the online analysis of a guest’s lane change by means of driving dynamics simulation. The rear instability felt by the customer can be explained by means of footprint analysis. The reduced tire pressure on the rear axle can no longer sufficiently build up the necessary lateral forces (see footprints on the left).

Complex task quickly solved

Interventions in the complex bus system of the vehicle had to be “invisible” for the system itself to prevent trouble in the operating sequence. To comply with the tire manufacturer asked IXXAT to take over. The specialist for complex data communication from Weingarten offers an embedded platform that already consolidates different bus systems in a single device with own computing capacity. The platform knows innately different transport protocols and was therefore perfect for the quick implementation of a practicable mass test on the designated vehicle.

The data were extracted by IXXAT FlexRay to CAN gateways with adjusted configuration and/or analysis tools in the vehicle, forwarded to the telemetry, transmitted, externally processed and visualized. The alternative of a purely CAN-based solution was quickly dismissed. This would have required a vehicle less suitable for the test and the parameterizing effort for the driving dynamics simulation would have been significantly increased. This approach was no option due to the limited time horizon.

Bild6 

Image 6: The hardware components FRC-EP190 and FRC-EP170 save time and money as embedded platform, when it is about bus simulation or data retrieval.

Complex task under time pressure

Since the date for the event was already set, the technical preconditions had to quickly be created for the approximately month-long mass test. In addition, the highest equipment reliability was required, since repeating individual test drives was not possible within the tight time frame. Mr. von Schnakenburg explained: “With the hardware components FRC-EP190 and FRC-EP170 (Image 6) in connection with IXXAT’s gateway configuration software we could complete the total development for implementing the measuring technology including processing the telemetry with four employees in approximately five months.” Christian Cramer adds: “The time advantage compared to all other solutions is, according to our experience, approximately factor 4. Furthermore, the procedure offers further advantages such as modularity and flexibility of the solution, high temperature stability, which is important for on-board use, high data quality as well as intuitive FlexRay to CAN conversion. Furthermore, logger functionality and, besides platform-independent visualization capability, also sustainable extension such as CAN-FD is offered.”

“In this way the schedule was perfectly adhered to. No basic development was necessary and the interaction of the components with the designated vehicle was perfect. In numbers, it were 20 man months compared to 80 man months otherwise necessary, approximately 9600 saved working hours, which finally also benefited the budget,” reports Mr. von Schnakenburg. “Since all technical components interacted perfectly and the system worked reliable and stable during the entire event, this was also an important issue for the external presentation of the company. In this way also the marketing and sales departments could benefit and Continental could distinguish itself as an innovative partner around tires, vehicle and driving tests.”

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