Advanced graphics in automotive instrument clusters

September 13, 2012 // By Michael Staudenmaier, Freescale
The instrument clusters of today's cars show a clear trend away from electromechanical pointer instruments and toward solutions with significant focus on graphical displays. This paper provides an overview of automotive instrument clusters with advanced graphic capabilities - today and in the foreseeable future. In this emerging field there is still a quick evolution ongoing driven by customer expectations influenced by graphical solutions from the consumer world. Bringing those expectations together with automotive quality requirements at affordable cost is still a challenge that has to be addressed by new methodologies and tools.

In this paper the discussion of instrument clusters is split into several topics: the use-cases, graphical techniques, technical implementations and design decisions taken in such complex embedded systems. As there are many techniques adopted from the PC arena a quick overview of selected areas is presented and its adoptions for the embedded world are outlined.

A focus is put on the creation of the graphical content and human-machine interfaces and the evolving tools support in that area. This paper shows several approaches and solutions for a smooth development flow starting from HMI graphics development down to optimized porting on embedded graphic accelerators.

While current designs focus on imitating classical pointer instrument clusters, this paper will show some upcoming trends and possibilities in the design of advanced user interfaces.

1      Introduction

In recent years the traditional mechanical automotive instrument cluster has been more and more extended by electronic displays. The first step in the evolution was the introduction of liquid crystal displays used for mileage information and other simple alpha-numeric information.

Figure 1 : Alfa Romeo Giulia Spider Instrument Cluster

The reduced prices of TFT displays and the availability of the required compute performance in the embedded space now allow affordable graphic based solutions. As the instrument cluster is one of the most prominent parts of the HMI and very evident to the driver it is an important differentiation feature for the car manufacturers. For high-end cars this leads to the situation that manufacturers are significantly increasing the level of investment into that area. Currently TFT displays in that area still seem to be considered an added value in itself by the driver as it is considered a high-tech feature. Since the “gauges with moving pointers” visual paradigm is well accepted by consumers and can very quickly communicate both speed and acceleration to the driver, it is necessary to simulate the mechanical instruments using advanced graphic technology. Exploitation of additional

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