Timing problems in real-time control systems.
Björn Wittenmark, Johan Nilsson, Martin Sanfridsson, Martin Törngren · 1998
The paper formulates and discusses timing problems in real-time systems. Different ways to eliminate the effects of communication delays are considered. 1. Introduction Many real-time systems are implemented as multiprocessor or distributed computer systems where timing problems can arise when implementing real-time control systems. For instance, the network can cause time-varying delays in the communication within the system and the multiplexing of several tasks by operating systems can cause unacceptable time-variations for the control purposes. The focus in this paper is on timing problems from a sampled-data point of view. In this theory timeinvariance is usually assumed and it is common to use equidistant sampling. Time-invariance requires that control delays are constant and that control and sampling actions take place at well defined instants in time. The time-variations must be negligible compared to the dynamics of the controlled process or included in the design. While inac...