RT control scheduling to reduce control performance degrading

Abstract

In the framework of RT digital control, two fundamental parameters are defined, the control effort and the control action interval. The first one is related to the strength of the control that, due to the intersampling open-loop control, determines the degrading of performances under unexpected delays. The second one refers to the unavoidable delays in the multitasking environment due to interactions among the tasks. As a consequence, the scheduling policy should consider not only the tasks delays but also their influence in the control loop behavior, being calculated to minimize the overall degrading of performances.

A novel approach to periodic event-triggered control: Design and application to the inverted pendulum

“…The theory of sampled-data system is well-known [20,21], and its results are useful for the analysis and design of control systems. In periodic control, the control law is executed periodically and it can be represented as a delayed input as follows:…”

“…The system (19) is asymptotically stable with feedback gain K under the event-triggering condition (20), if there exist a positive definite matrix P, a positive scalar σ, scalars q 4 1 and κ i 4 0; i ¼ 1; …; 4, and a positive period h such that the following inequality is satisfied:…”

Implementation of algebraic controllers for non-conventional sampled-data systems

“…Starting from previous studies, (Salt et al, 2002;Salt and Albertos, 2005) relative to the design of regular dual-rate controllers, now controllers with non-conventional (irregular) structure will be posed. These controllers will be able to control those processes which are sampled in a nonconventional way, due to, for example, the existence of delays when the physical medium between controller and process is shared (Casanova and Salt, 2003) or when different real-time task priorities are considered (Albertos et al, 2000). In the design step, and in order to use a simpler and more efficient notation, the fast period will be denoted by T and the slow period (metaperiod T 0 ), will de denoted as NT, where N (assumed integer) is the multiplicity (that is, the relation between fast and slow period).…”

“…For example by implementing a real-time control scheduling approach (Albertos et al, 2000) or by means of a hardware reconfiguration of the system in order to be considered as an integrated communication and control system (Casanova and Salt, 2003).…”

The control server: a computational model for real-time control tasks

“…The idea of reducing jitter using dedicated, high-priority tasks or interrupts handlers for input and output operations has been proposed many times before, e.g., [19,14,8,2].…”