Stabilisability and detectability in networked control (Regular Papers) (original) (raw)
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Stabilisability and detectability in networked control
IET Control Theory & Applications, 2010
We reconsider and advance the analysis of controllability and observability (and the weaker stabilisability and detectability properties) of a class of linear Networked Control Systems (NCSs). We model the NCS as a periodic system with limited communication where the non-updated signals can either be held constant (the zero-order-hold case) or reset to zero. Periodicity is dealt with the lifting technique. We provide conditions for controllability (stabilisability) and observability (detectability) of the NCS given a communication sequence and the controlled plant model. These conditions allow to find communication sequences which are shorter than previously established. A strict lower bound for the sequence length is given. In the sampled-data case, we prove that a communication sequence that avoids particularly defined pathological sampling rates and particular eigenvalues can preserve stabilisability (and detectability for the dual problem) with a 'minimum' sequence length.
Controllability, Observability in Networked Control
6th IFAC Symposium on Robust Control Design, 2009, 2009
We reconsider and advance the analysis of structural properties (controllability and observability) of a class of linear Networked Control Systems (NCSs). We model the NCS as a periodic system with limited communication where the non updated signals can either be held constant (the zero-order-hold case) or reset to zero. Periodicity is dealt using the lifting technique. We prove that a communication sequence that avoids particularly defined pathological sampling rates and updates each actuator signal only once is sufficient to preserve controllability (and observability for the dual problem of sensor scheduling). These sequences can be shorter than previously established and we set a tight lower bound to them.
Stability analysis of networked control systems with unknown inputs
2014 52nd Annual Allerton Conference on Communication, Control, and Computing (Allerton), 2014
This article proposes a novel approach to assess the stability of linear systems with delayed and sampled-data inputs. The paper considers both asynchronous sampling and input delay based on an extension of existing results on the stability of sampled-data systems to the case where a delay is introduced in the control loop. The proposed method provides easy tractable sufficient conditions for asymptotic stability of sampled-data systems under asynchronous sampling and transmission delays. The period and delay-dependent conditions are expressed using computable linear matrix inequalities. Several examples show the efficiency of the stability criteria.
Stability analysis of networked control systems
1999
This article proposes a novel approach to assess the stability of linear systems with delayed and sampled-data inputs. The paper considers both asynchronous sampling and input delay based on an extension of existing results on the stability of sampled-data systems to the case where a delay is introduced in the control loop. The proposed method provides easy tractable sufficient conditions for asymptotic stability of sampled-data systems under asynchronous sampling and transmission delays. The period and delay-dependent conditions are expressed using computable linear matrix inequalities. Several examples show the efficiency of the stability criteria.
Mechanical Engineering, 2018
This paper addresses the problem of optimal control and scheduling of Networked Control Systems over limited bandwidth deterministic networks using some insight on the interplay between the control and information theory. The motivation is related to the necessity of choice a communication sequence which maximize control signal impact on the plant behavior. The solution is obtained by decomposing the overall problem in a twofold one. The first level problem aims obtaining the periodic off-line or static scheduling function of control signals based on system properties, communication constrains, periodicity of scheduling sequence, performance criteria and maximization of the degree of reachability/observability of the periodic system. A Mixed Integer Quadratic Programming (MIQP) problem is formulated and solved obtaining a periodic and stable NCS. The solution of the second level problem is based on the structure of the static scheduling function obtained from the first level solutio...
IFAC Proceedings Volumes, 2008
This paper studies the controllability and observability of discrete-time systems with network-induced variable delays. Since controllability and observability are structural properties of systems, which are first checked before control design, we study if a controllable (resp. observable) non-delayed system can loose these properties if we augment the model with particular pure input-output variable delays caused by a situation of overload in the networked control architecture. We start our approach with a discrete-time multivariable linear time-invariant system with non-equal network-induced delays on control signals (inputs) and measures (outputs). The considered delays may only remain constant or increase with unitary increments. We prove that if a non-delayed system is controllable (resp. observable), then the network-delayed system is controllable (resp. observable) despite the monotonicallyincreasing delay values in each input/output channel. This general powerful result ensures further implementation of model-based predictive control strategies based on state observers methods for the considered model of networked control systems.
Stability Analysis of Networked Control Systems with Time Varying Sampling Periods
控制理论与应用：英文版, 2008
This paper addresses the stability of networked control systems with aperiodic sampling and time-varying network-induced delay. The sampling intervals are assumed to vary within a known interval. The transmission delay is assumed to belong to a given interval. The closed-loop system is first converted to a discrete-time system with multiple time-varying delays and norm-bounded uncertainties resulting from the variation of the sampling intervals. And then, it is transformed into a delayfree system being form of an interconnection of two subsystems. By utilizing scaled small gain theorem, an asymptotic stability criterion for the closed-loop system is proposed in terms of linear matrix inequality. Finally, numerical examples demonstrate the effectiveness of the proposed method and its advantages over existing methods.
State estimation for networked control systems using fixed data rates
International Journal of Systems Science, 2017
This paper investigates state estimation for linear time-invariant systems where sensors and controllers are geographically separated and connected via a bandwidth-limited and errorless communication channel with the fixed data rate. All plant states are quantised, coded and converted together into a codeword in our quantisation and coding scheme. We present necessary and sufficient conditions on the fixed data rate for observability of such systems, and further develop the data-rate theorem. It is shown in our results that there exists a quantisation and coding scheme to ensure observability of the system if the fixed data rate is larger than the lower bound given, which is less conservative than the one in the literature. Furthermore, we also examine the role that the disturbances have on the state estimation problem in the case with datarate limitations. Illustrative examples are given to demonstrate the effectiveness of the proposed method.
Some problems in the stability of networked-control systems with periodic scheduling
International Journal of Control, 2010
This article addresses three stability problems related to networked-control systems (NCSs) with periodic scheduling, where control systems may have multiple samplings in a hyperperiod (a hyperperiod is a periodically repeated scheduling sequence for all tasks in an NCS). As expected, the analysis of a system with multiple samplings is much richer than the case with single sampling. For example, a system with two samplings may be stable (unstable) even if it is unstable (stable) when sampled by either sampling. In this context, it is important to understand how network-induced delays and multiple samplings affect the system's stability. In this article, three particular stability problems involving constant and/or time-varying parameters are investigated, and the corresponding stability regions are derived. Numerical examples and various discussions complete the presentation.