This paper provides sufficient conditions for controllability of discrete time linear systems with input saturation. Controllability is a central notion in linear system theory, optimal quadratic regulators as well as model predictive control algorithms. The more realistic notion of constrained controllability has given less attention probably due to mathematical complications. Most of the existing works on constrained controllability studies the properties of reachable sets. However, there are only a few works which investigate the problem of whether a state is reachable or not. In this paper, a set of sufficient conditions are firstly given for constrained controllability of time varying linear systems in discrete time formulation. The given conditions are obtained using the Farkas’ lemma for alternative inequalities. The obtained results improve existing literature by providing conditions for both null-controllability and controllability regardless of the system stability. A sufficient condition is then given for the special case of time invariant single input linear systems with diagonal Jordan canonical form. Numerical examples are given for clarification. Manuscript profile

This paper studies structural properties of bandwidth limited Industrial Networked Control Systems in which the number of simultaneous network accesses is limited. Conventional control theory assumes that the measured output is available as a vector at each time instant and the input vector can be applied simultaneously to the actuator. However, when the system is bandwidth limited, it is not possible to instantly read all of the sensors and nor it is possible to apply the whole input (control) vector to the actuator. As a result, a system which is controllable (reconstructible) for its own, may not preserve this property when the communication medium is bandwidth limited. The communication medium therefore changes the overall system structural properties. This is of utmost importance since existing control and estimation algorithms are based on the assumptions that the whole output vector (input vector) is read from sensors (applied to actuators) instantly. We assume that communication medium is shared among both sensors and actuators. It is shown that controllability and reconstructibility analysis could not be performed independently (as inherently assumed or ignored by previous works in this field). For the special case of equidistant sequences with separate read/write cycles, we prove that controllability and reconstructibility analysis’s can be done independently if a specific procedure is followed. Examples are included to clarify the results. Manuscript profile