Diagnostic tool interaction design for DAF and Paccar mechanics
J. Oude Egberink · 2010
This report presents a reinterpreted Human Machine Interface (HMI)design aimed at the DAVIE diagnostic tool and facilitating an efficient workflow for DAF and Paccar mechanics. It describes the process thereof as part of a graduation project for Master degree in Industrial Design Engineering at the faculty of Industrial Design at the University of Technology in Delft. The DAF Vehicle Investigation Equipment (DAVIE) diagnostics tool, specially developed for DAF Trucks, is used by mechanics in the workshops of its dealers or for road side assistance to diagnose malfunctions, change vehicle systems setup and perform repair and maintenance. Due to new legislation and as the truck’s configurations become more complex DAVIE needs to adapt accordingly. The current DAVIE is focused on the truck’s internal components and rather disregarding the user’s workflow. This perspective needed to be altered to a more User Centred Design approach and so the interaction needs to be reinterpreted to facilitate an efficient workflow. The new tool and design will be developed and implemented within DAF and Paccar and will find its way to all its dealers. Within the design process, the navigation of the HMI design is defined according to use cases from the field and the user research by carefully dissecting, merging and rearranging DAVIE functions with the mechanic’s workflow in mind. A quite complex tool became ‘simple’ in structure. The design is consistent throughout all functions to reduce acclimatization for the mechanic. The entire GUI is designed for use with touch screen and therefore has widely spaced, large enough buttons. A system is developed to provide feedback about where the user is in the navigation, what steps were taken, and provides accessibility to return to these steps. The user can go ‘Home’ in one touch. The way items in the content are presented to the mechanic forms an important part as such system appears in every DAVIE function. The hierarchical categorization is made transparent to the mechanic and consistent throughout all functions in order to facilitate understanding about interrelations. This aspect manifested in two ways: a categorised list in which loose items and their hierarchical relation can be identified and a schematic of the vehicle’s ECU’s (Electronic Control Units) representing the vehicle’s ECU structure. An easy accessible system to acquire background or detailed information is developed to supplement the mechanics knowledge. To provide transparency towards DAVIE’s connection to the network and truck, a status display is developed representing the actual parts, configuration and connection status. Pop-ups were developed to present procedures which the mechanic can perform on the vehicle. These along with the rest of the tool’s content are written by the DAF authoring environment and so providing content (knowledge) to the tool for the mechanics. Dialog boxes (pop-ups) present warnings, questions or progress of processes to the user. The mechanic always knows where he is through half opacity when presented with such a pop-up or dialog box. To validate the design in advance of developing and launching it in the field a usability study is conducted in the Netherlands and North America with mechanics. This research aimed to validate the usability of the developed workflow and navigation concept, terminology (readability, icons) and the various HMI design aspects. Cases from the field were used and a prototype is developed with the content to support these cases. Generally several mechanics remarked the new tool to be user friendly. During the tests the participant succeeded in solving the various cases; sometimes not at first try, but at second or third. Therefore the HMI design can be argued to be quite successful as the tool is entirely new and unfamiliar for the participants. They had never seen the interface and some functions were new for them. Results, conclusions and recommendations from the research were subsequently implemented in a HMI redesign.