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3.1. Proactive Furniture
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Figure 3.1: Steps 1 to 4 of the IKEA assembly instructions.
(Reproduced with the permission of the IKEA corporation)
them into the related objects. Instructions could be split into smaller portions –
hints – that subtly but infallibly guide users towards correct conclusions. These hints
should be tailored to the user’s momentary task. Each hint helps in one dedicated
situation, in contrast to manuals covering all error cases. Smart-Its technology was
used to realize the implementation of proactive hints, i.e. hints that occur in the
physical world of the user synchronized to the task of a flat-pack furniture assembly.
As such, the furniture assembly project was used to illustrate the benefits of using
Smart-Its technology in furniture assembly compared to today’s paper instructions.
3.1.2 Observing the Assembly Task through Sensors
In this section we present the sensor based approach for perceiving the assembly
actions when assembling a simple example wardrobe. The wardrobe we chose con-
sists of six wooden boards, two metal corners, cams, cam bolts, dowels, screws, and
nails. For a standard assembly of the wardrobe, a screwdriver and a hammer are
the only tools required. As shown by Figure 3.1, the first step is to insert the four
cam-bolts in each board at the right positions. Then two metal corners have to be
attached. In the third and fourth steps one of the horizontal boards and the base
strip are attached to a side-board. Before attaching these boards, they need to be
prepared with dowels. The last step is to tighten the cams.
These actions are subdivided into partial actions, which can be recognized by sensors.
The partial actions are compared with a stored assembly plan of the furniture. Thus,
the system can determine the user’s current step and reason about further actions.
Assembly Plan
In order to assist the user, the system needs a plan representing the di erent ways
of assembling the wardrobe. In this subsection we present such a plan.
To create a plan we gave the wardrobe parts the following identifiers: side boards a
and b, horizontal boards c and d, base strip e, and back wall f. Figure 3.2 shows the
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