Testing Human Machine Interface (HMI) Rich Designs using Model-Based Design 2008-01-1052

Today's vehicles are typically outfitted with passenger convenience features that require Human Machine Interfaces (HMIs). HMIs can be relatively simple - such as a remote key fob - or more sophisticated - such as a radio face plate. Traditional development of HMIs involves two typically independent processes - (1) Physical Component Design and (2) Functional Logic Design. The physical component design is developed by a team that usually includes both graphics and ergonomics designers to ensure that the HMI is intuitive and fits well with the interior styling of the vehicle. The functional logic design follows a more typical software development process. This process is based on functional requirements commonly written in terms of user requests and system responses as represented by the HMI. As the complexity of the system increases, it is essential for the intuitiveness and ease of use of the HMI to advance as well. For teams using traditional methods to design, prototype, and fully test an HMI, achieving this level of ease of use is becoming increasingly challenging. In an earlier paper, the authors demonstrated how to create a “soft” version of the HMI under development and then use this to generate and record test vectors [1]. These test vectors could then be used to exercise the design under test to determine if the HMI logic was completely tested and if the design met the specified requirements. In this paper, the authors will address two important workflow issues to support the logic design and verification of HMIs - (1) integration of the HMI graphics and HMI logic and (2) formal verification of the HMI logic.