Abstract
Keywords
HMI architecture, component-based design, MVC pattern, COTS, automotive multimedia
Abstract
HMI specification and development processes for automotive systems incorporate electronics components with very different levels of complexity, safety requirements, and software models, from hard real-time embedded systems (dashboards, air conditioning) to more classic software layouts (multimedia, navigation).
Moreover, customer-visible vehicle diversity and optional equipment choices, together with cross-vehicle line component reuse and increasingly disconnected lifecycles between core components and ITS/multimedia features, make it especially hard to manage the dependencies between HMI instances and vehicle configurations Software management and maintenance costs become far from negligible.
This paper describes an approach undertaken at Renault to limit the impact of those dependencies by enforcing software interfaces at various system levels. Those interfaces are intended to isolate :
- HMI applications from one another;
- HMI applications from the functions they control;
- Components from the network implementation used in the system, allowing a better control over embedded software and hardware diversity.
Based on previous attempts in the telephone and multimedia industries, as well as in the automotive area, this approach includes a set of application programming interfaces, translation of those interfaces into production network protocols, and a collection of tools allowing to carry out some isolation between the various professional skills involved in the specification process.
One of the core concepts used is the introduction of a pair of distinct intermediate entities in charge of managing HMI resource arbitration on one hand, and multimedia presentation on the other hand in the distributed device environment of a car. Those entities collectively contribute to extend the ubiquitous Model-View Controller (MVC) design pattern for HMI applications to what could be called switched-MVC. Care is taken to guarantee that those abstractions can survive exposure to low end system and legacy components.
Lessons learned and future directions are outlined, in terms of both technical elements and engineering and business processes.