Creating Human Machine Interface (HMI) Based Tests within Model-Based Design

Many of the multimedia and convenience features in today's passenger vehicles involve Human Machine Interfaces (HMIs), such as the radio face plate or the remote key fob. The functional requirements for these systems are often written in terms of the customer interaction with the interface device. In the past, design engineers would not begin to test requirements for these systems until prototype hardware was available. However, many product development organizations are shifting from this hardware-based traditional development cycle, which relies on designing via a prototype and test iteration, to Model-Based Design. Unfortunately, testing systems with complex human machine interface requirements becomes less intuitive when the prototypes are removed from the design process, because the test cases must be scripted into the modeling environment instead of being applied directly to a prototype of the interface device. In this paper we will show how engineers can create a “soft” representation of an automotive HMI and record the test procedure when specified as a series of interactions with the interface, such as button presses. Next, we will demonstrate how the test procedure can be captured and exported to an editable file for re-use with Model-Based Design. Lastly, we will show how a test file can be used to populate a test harness within the Simulink® software environment.