Hardware Reference
In-Depth Information
11
APPLICATION DESIGN ISSUES
In this chapter we discuss some important issues related to the design and the devel-
opment of complex real-time applications requiring sensory acquisition, control, and
actuation of mechanical components. The aim of this part is to give a precise char-
acterization of control applications, so that theory developed for real-time computing
and scheduling algorithms can be practically used in this field to make complex control
systems more reliable. In fact, a precise observation of the timing constraints specified
in the control loops and in the sensory acquisition processes is a necessary condition
for guaranteeing a stable behavior of the controlled system, as well as a predictable
performance.
As specific examples of control activities, we consider some typical robotic appli-
cations, in which a robot manipulator equipped with a set of sensors interacts with
the environment to perform a control task according to stringent user requirements.
In particular, we discuss when control applications really need real-time computing
(and not just fast computing), and we show how time constraints, such as periods and
deadlines, can be derived from the application requirements, even though they are not
explicitly specified by the user.
Finally, the basic set of kernel primitives presented in Chapter 10 is used to illustrate
some concrete programming examples of real-time tasks for sensory processing and
control activities.
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