Mission Profiles In The Automotive Development Process

The automotive industry’s roadmap for the coming years is e-mobility and autonomous driving. Its implementation is likely to bring about changes on a par with the invention of the automobile itself.

While the motor vehicle used to be primarily a mechanical product, it is now an entirely electronic system. Many of the new functions increase the safety of the driver and other road users, and therefore require a special safety-oriented development process. This means many components have to be newly developed to achieve the safety goals.

Unfortunately, products from the consumer sector only can be used to a limited extent in such scenarios, as completely different requirements have to be met. For example, while the service life of about 2 years is often sufficient for a consumer product, 10 to 15 years is considered the standard in the automotive sector. And that time frame is despite high loads in terms of temperature, humidity or mechanical stress.

The external loads on the individual components usually are known only to the OEM. They know where a component is installed and what the exact lifecycle of the component looks like. Ultimately, representative load profiles are derived from these parameters, and­ those load profiles are incorporated into guidelines such as the LV124 or VW80000.

In addition, there are many other requirements that have to be communicated in different ways between the development partners. Loads that the component itself generates, such as self-heating, often are known only to the supplier. As the development process becomes more complex, so too does the demand on communication. So-called mission profiles are used to exchange the load profiles. A mission profile is a simplified representation of all relevant static and dynamic load conditions that a vehicle component is exposed to within its lifecycle. That lifecycle includes production, testing, storage, transport and the operational and passive use of a component.

A special challenge in the automotive development process currently lies in exchanging information about mission profiles securely, completely, and without contradictions between the development partners along the value chain. Many iterations or even faults could be avoided if the exchange of this data were unambiguous and based on standards. Unfortunately, information about mission profiles is still exchanged between development partners in many generic data formats, some of which have grown over time, such as Microsoft Excel or Requirements Engineering data sets. While an Excel sheet may be sufficient for simple relations, the complexity of a mission profile only becomes apparent at second glance:

• Loads can be histograms, tables or functional relations
• Loads have physical units that differ regionally
• Variables can have tolerances or be statistically distributed
• Loads are often multidimensional, e.g. regarding temperature and humidity
• Loads can occur cyclically, e.g. mornings, Monday to Friday, and especially in winter
• Load profiles can be hierarchical, e.g. self-heating can be overridden by the ambient temperature
• Loads can occur simultaneously or sequentially, etc.

In view of the challenges outlined for automotive development today and in the future, the partners along the supply chain agree about the need for a standardized exchange format to transfer mission profiles among each other. Unfortunately, on closer inspection, existing data formats such as ReqIF, SysML, PMML, LML, or RIIF are not suitable for capturing the complex and specific relations that can occur in a mission profile. Therefore, a consortium of industrial and research partners currently is working flat out on the further development and IEC/ISO standardization of the MPFO data format, which offers a prototype solution for the exchange of mission profiles. The working group incorporates the feedback from all supply chain participants and transfers it to the data format. Following the standardization, the format can be implemented in appropriate software tools.

In summary, the standardized exchange of mission profile information between development partners in the automotive supply chain is an essential element in the development of reliable components and systems for future vehicle generations. To this end, the standardization of a file format for mission profiles is currently being pushed forward.