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3.1. Proactive Furniture
35
(a)
(b)
Figure 3.3: Figure (a) shows the x and y output of the accelerometer when joining
boards attached to a horizontal board during the preparation phase. In Figure (b)
the outputs of the screwdriver, force sensor, and accelerometer are plotted during
the action of joining the horizontal board to the sideboard.
to the long board. On each board a PIC microprocessor collects and evaluates the
sensor data. The microprocessors communicate wirelessly to share information (see
[
Holmquist et al. 2004
] [
Antifakos et al. 2002
]
for more details on the hardware
implementation). This combination of sensors allows the system to determine the
current step of assembly and to reason about possible future steps.
3.1.3 Instructing the User
The previous section has shown how a microprocessor system can detect the current
state of the assembly and the user’s action through sensors. By looking-up the
state of the assembly of an action in an assembly plan, the system can reason about
possible future steps and provide this information to the user. This section describes
how the system can provide guidance to the user in an intrinsic way (see Figure 3.4).
To guide the user through the flat-pack furniture assembly, we have identified five
types of feedback: (1) direction of attention, (2) positive feedback for correct action,
(3) negative feedback for wrong action, (4) fine-grained direction, (5) notification of
finished task.
Augmented Reality (AR), as evaluated in
[
Tang et al. 2003
] [
Zauner et al. 2003
]
,
is an established technology to visually integrate virtual knowledge into a user’s
physical environment. However, AR is cumbersome and typically computationally
expensive. Audible instructions o er a cheaper way of immersion but have to cope
with the problem of addressing the appropriate parts by a vocabulary the user is
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