Optimization of Man-Machine Interface in Loader Cabs: Grouping and Arrangement of Control Actuators
Abstract: This project concerns an optimization of the button layout in loaders and trucks stationed in underground mines, with emphasis on loaders. More buttons have been added throughout time and these have been placed after the compromises of a minimum of space, economy and the tough environment they are exposed to. The optimal user interface has thus been suffering in the process. The project concerns several vehicles that all have different panel layout. The objective is to present guidelines for a general layout and produce three different concepts. The project aims to identify features in the cab and to group and place them so they are perceived more intuitive, natural for the user. This is to improve ergonomics for drivers and, with theory and a broad view through a large part of the range of loaders and trucks, bind together the features that are common in to modules. No commercial design will be considered, only a schematic placement. Choice of buttons, levers or actuators, and its design will be discussed in general. The theories regarding grouping and placement of control actuators are found in numerous scientific articles, books, standards and in recommendations from large occupational health organisations.
The work begins with project administration by making a Gantt chart of the sub-parts and its dedicated time and a decision of doing the project parallel to the development project of two new cabs at Atlas Copco, thus this project would not be influenced by Atlas Copcos’ existing culture and norms. The information gathering process is the backbone of this project. It consists of the mapping of functions, field trips and observations, test drives, qualitative interviews of operators, test drivers and service engineers, internal/competitive/industrial benchmarking, literature study and meetings with several different department e.g. Industrial Design and Blast Hole Drilling Rigs. After the gathering of information the creative part begins, creation of design guidelines, defining button areas and creation of concepts. The three concepts were evaluated by test drivers and optimized to one recommendation.
The result of this project is three different concepts of button layout based on the same design guidelines. Concept 1 is based on the idea that the driver could hold on to the levers all the time while working. The functions that have the lowest frequency of use could be placed on the panel but all the other functions should fit on to the levers. Because the levers only have ten buttons all together some merges of functions, double-click functions, hold-down functions and combinations had to be made. Concept 2 is a compromise of the two extremes. Concept 3 is based on the idea of not using the left lever for the placing of buttons. The panel is therefore the critical point in this concept and the interface is optimized through placing and grouping of the different features.
The result of the evaluation showed that the total score of all three concepts were almost the same and therefore all three concepts could work in practice. Concept 3 has the lowest risk of making mistakes. This shows that even though all the buttons are clamped together in a small area the theories regarding grouping and placing controls work in practice. “Logical placing of controls” got almost the same score in all three concepts and this shows that the guidelines are correct for logical placing of controls and can generate different kind of layouts that are equally logical.
The recommendations to Atlas Copco is to combine the strengths in concepts 1 and 3 with fully equipped lever and a full panel for redundancy of controls and automatic climate control located in the ceiling.
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