Biomedical Engineering Reference
In-Depth Information
volume). From there, it becomes necessary to be mindful of this variability
in order to support the effectiveness and efficiency of actions targeted by
gestures. They constitute a resource for system performance. The design
of work systems implies defining leeway for gestures in real-time produc-
tion and in learning.
Let us illustrate this idea with an example from a company in the
automotive sector. In this company, which has implemented measures
for work standardization, managers are notably tasked with defining
gestural prescriptions. These prescriptions are given in 'operation sheets'
(Chassaing, 2010). These operation sheets present only one way of doing
things, and there is no possible choice for the operator, thus leaving little
room for the variability of gestures. Here is an example of a prescription:
Using both hands, take the lining (i.e. the piece
forming the inside casing of a car) from the TM
(a large container). Placing the left hand in the
oblong openwork, next to the wheel's passage space,
the right hand should be in the central part of the
rear side panel. When leaving the TM, rotate the piece
90 degrees right.
This prescription restricts operators as they are looking to balance the
piece, to control it, to spread their arms depending on their height. Because
of this, they adopt modes of operation that are widely different from what
is recommended by the prescription. This prescription becomes a con-
straint for operators, who position their hands differently on the lining,
so as to handle it differently from what is prescribed. These gestural solu-
tions allow operators to achieve their goals related to safety, comfort, mus-
cular fatigue and effectiveness, which are not taken into account in the
instructions. On the contrary, prescriptions should not constrain modes
of operation, but allow and indeed encourage operators to construct a ges-
tural solution. Here is an example of a prescription that offers potential
margins of manoeuvre for operators to construct gestural solutions:
Place the lining in the assembly, simultaneously
matching the top left guide of the assembly with
the top cylindrical hole of the lining, and matching
the central guide of the assembly with the central
oblong hole of the lining.
Here, the prescriptor only suggests guides regarding the results of
action. The position of the hands is not mentioned, and this operation
therefore leaves operators with some freedom regarding how to do the job.
