Exploring Variation Mechanisms in the Automotive Industry
Introduction Today car manufacturers produce large no. of Customized Cars to meet customer demands & to support after market services. But it is impossible to anticipate all configuration at design time. Therefore they focus their attention to “Software Product Line Method” rather than production line method
Software Production Line Method Focus on the methods & tools required to create similar product based on a collection of software assets. Objectives: Increase the ability to re use software To meet customization requirements Vital Aspect: “Variability Management”The combination of assets to form a single, possibly, uniqueproduct
Variant Handling: Ability to modify a system without making a big impact on the system or imposing a need to restructure the design. Eg: Inside Lighting System depend on the installed doors in the car.
Variability: Is defined in the architecture through variation points, or a specific place in the architecture at which a feature can take one of two or more shapes. Variability Sources: In Function In Data In Technology In Control Flow In Environment In Quality
4 Variation Patterns Pattern E.g. of Mechanism Binding Time UsageProduct Configuration Pre-build Implementation duringArchitecture management, the architecture &Derivation Generators design phaseCompilation Compiler Switches Pre-build Compiler flags will resolve to one binary outputLinking Binary Replacement Pre-build Linkage with library/ binaries to produce one binary outputRuntime Adoption during start up Post-build Uses inline code to condition on variable resolve variability at runtime.
AUTOmotive Open SystemARchitecture (AUTOSAR) An open & standardized architecture for the automotive industry. Jointly developed by the largest companies within the industry together with 3rd party suppliers & tool developers. Aim to improve the way electronic equipment is developed, increase safety, performance & environmental friendliness.
Modules introduce in the standard UML Meta Models Annotated Meta Model Extended Meta Model 4 patterns describe in the standard, Aggregation Value Standard Association Value Standard Attribute Value Standard Property Set Value Standard
What is a Quality Tree?? Way of assessing & categorizing variant patterns used in an organization. Leaf nodes represent strength &weaknesses discovered during the implementation. Provide, Guidance for the architect when making decisions for how to manage variability. Good overview of the characteristics of one specific pattern.
Mainly Focus Focus on key elements required to support run time variability using the AUTOSAR 4 .0 Standard through developing a prototype.
Research MethodThere are 3 subsections, Case setting Data source. Process
Case Setting Problem based on the Volvo Car’s preconceptions for managing variability to implement a variant mechanisms for run – time variability. There are three stages in development that variants are used today at Volvo Cars. They are, compilation mechanisms local parameterization distributed parameterization.
Data Sources Sources Type Advantages Limitations Volvo cars Document, architecture Valuable information Restricted by component specification based on refined confidentiality specification domain knowledge. agreement.PrimarySources Volvo cars Document Valuable information Draft document, run-time ,architecture based on refined may change. variability specification domain knowledge. Restructured by specification confidentiality agreement. Software Regular discussions 10 year of hand- on Data is architect at architect experience interpreted twice. Volvo cars at Volvo carsSecondary AUTOSAR Documents and UML Publicly available. Difficult toSources 4.0 meta-models Thorough and with address all specification examples. relevant sections.
ProcessUnder this step we can divided the implementation intothree phases. C Implementation - Written entirely in C CAN-bus Implementation - Written entirely in C AUTOSAR Implementation - Developed using AUTOSAR complaint tools.
To assess the specification provided by Volvo cars. First phase-: Intentionally avoided any use of “AUTOSAR”. Consequently this made it possible to discover what was required of the variant before making the prototype more true to the automotive environment. Second phase-: Findings from the first phase were used to further refine the implementation towards the automotive industry. Third phase-: Based on the findings with some limitations from the previous phases.The company started the development based on the following premises andrequirements. As much as possible takes place run-time. A solution must be independent from the data it is supposed to pass. Data used by a services does not have to be stored on the ECU where the service running.
Research Data The results outlined in this slides are coming from a prototype implementation of a run – time variability pattern. Publisher-subscriber which is a mechanism for components, during application execution, to subscribe to state updates generated by another component, the so called publisher. Volvo Cars specification in its current state does not require subscription to take place in run-time.
Highlighted aspects derived during the development: Subscription Multiple Publishers Push & Pull Strategies Register Parameters of Interest Local & Global configuration files Parameters in an AUTOSAR environment
Automotive Industry Following factors have introduced for the motivation of variability in AUTOSAR. Establish a common language to enable suppliers and manufactures to work together. Use to avoid redundancy between artifacts. It provides a basis for basic software product line.