Page 21 - Classification Parameter Estimation & State Estimation An Engg Approach Using MATLAB

10 INTRODUCTION

from preceding stage of the design process

task definition

design concept generation

analysis / evaluation

decision

to next stage of the design process
Figure 1.5 An elementary step in the design process (Finkelstein and Finkelstein,
1994)

the design issue with an evaluation criterion. The criterion expresses the
suitability of a design concept related to the given task, but also other
aspects can be involved, such as cost of manufacturing, computational
cost or throughput. Usually, there is a number of possible design con-
cepts to select from. Each concept is subjected to an analysis and an
evaluation, possibly based on some experimentation. Next, the engineer
decides which design concept is most appropriate. If none of the possible
concepts are acceptable, the designer steps back to an earlier stage to
alter the selections that have been made there.
One of the first tasks of the engineer is to identify the actual need that
the instrument must fulfil. The outcome of this design step is a descrip-
tion of the functionality, e.g. a list of preliminary specifications, operat-
ing characteristics, environmental conditions, wishes with respect to user
interface and exterior design. The next steps deal with the principles and
methods that are appropriate to fulfil the needs, i.e. the internal func-
tional structure of the instrument. At this level, the system under design
is broken down into a number of functional components. Each com-
ponent is considered as a subsystem whose input/output relations are
mathematically defined. Questions related to the actual construction,
realization of the functions, housing, etc., are later concerns.
The functional structure of an instrument can be divided roughly into
sensing, processing and outputting (displaying, recording). This book
focuses entirely on the design steps related to processing. It provides: