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The paper presents a model predictive allocation scheme for constrained over-actuated linear systems, for which input redundancy entails the existence of multiple trajectories in the state space yielding a given reference output. The method relies upon the concept of inverse model allocation, where dynamic allocation of reference state and input trajectories is accomplished within the framework of...
Monotone systems comprise an important class of dynamical systems that are of interest both for their wide applicability and because of their interesting mathematical properties. It is known that under the property of quasimono-tonicity time-delayed systems become monotone, and some remarkable properties have been reported for such systems. These include, for example, the fact that for linear systems...
In this paper we present a new approach of using input-output linearization to control a single input, single output, input-affine nonlinear non-minimum phase system. We will show that, if the linearized system is stabilizable, we can redefine the output of the system such that the input-output linearized system is locally asymptotically stable. Furthermore we develop an LQR technique for designing...
Sliding mode control (SMC) is one of the few controller design methodologies that can be applied to highly nonlinear and uncertain systems. In most mechanical applications, a smoothed version of SMC that we call “sliding control” is employed to keep the system trajectories close to but not necessarily on a stable differential/difference manifold. In this paper, we propose an extension to the sliding...
The paper presents the concept and stability analysis of a trajectory-tracking feedback control system for truly N-trailer robots equipped with arbitrary number of trailers interconnected by the non-zero hitching offsets. Thanks to application of the cascaded-like control structure the considered solution is modular and highly scalable with respect to a number of trailers. Formal analysis of the closed-loop...
In many practical applications, stability with respect to part of the system's states is often necessary with finite-time convergence to the equilibrium state of interest. Finite-time partial stability involves dynamical systems whose part of the trajectory converges to an equilibrium state in finite time. Since finite-time convergence implies non-uniqueness of system solutions in backward time, such...
In this paper we study the stabilization of systems with decentralized controllers, when the stability criterion of interest is “non-overshooting stability”. This criterion is stronger than those which have typically been studied, particularly for decentralized control, and requires that the size of the state is always decreasing. We identify a key property which allows centralized results for this...
This paper introduces a novel control law that dynamically modifies the reference of a pre-compensated nonlinear system so as to ensure the satisfaction of convex constraints. This is done by translating the state space constraints into a constraint on the Lyapunov function which is then limited by modulating the velocity of the applied reference. The main advantage of this approach is that it systematically...
We consider a large-scale switched nonlinear system which is composed as an interconnection of N nonlinear switched systems. Having assumed that every subsystem is ISpS (ISS) uniformly with respect to the unobservable switching signals, we prove a small-gain condition for the overall large-scale system to be ISpS (respectively ISS) uniformly with respect to the unknown switching signal. To solve the...
A contraction based stabilization problem of systems with approximate strict feedback form is considered here. A high gain feedback is used to force the system into singularly perturbed form. Contraction theory based recursive controller design and singular perturbation analysis is used to design a stabilizing controller for the whole system. It is shown that, explicit error bounds between trajectories...
In this paper we present a controller that achieves global input-to-state stabilty for a linear system of arbitrary relative degree, subjected to matched and unmatched disturbances. This controller combines the properties of a discontinous term, and a linear one, enforcing a conventional sliding mode using only partial state information. A direct and simple way of choosing the gains for this controller...
In order to reduce communication in network control systems, it is of great interest to be able to synthesize event-triggered control laws from continuous-time controls. This work proposes a new rule to design event-based stabilizing controllers for linear systems. More precisely, based on a given reference system, a state observer, and a quadratic Lyapunov-like function, an event-based sampling algorithm...
Motion control of UAVs is an interesting problem due to the nonlinear and underactuacted nature of their dynamics. This paper focuses on position and yaw control of a rotary-wing UAV with state and input constraints using an inner-outer loop control structure. The outer loop generates saturated thrust and reference roll and pitch angles, while the inner loop is designed to follow the reference angles...
This paper studies the relationship between trajectories of nominal and uncertain nonlinear systems evolving on non-uniform time domains. The theory of dynamic equations on time scale is used to analyze the stability of perturbed nonlinear systems. First, it will be shown that the error between the uncertain and the nominal trajectories remains bounded for a particular class of systems. Then, using...
In this work, we present the application of a neural network (NN) based adaptive control scheme for the purpose of trajectory tracking of an air-to-air missile. The nonlinear dynamic model of such missiles contain numerous aerodynamic coefficients. It is well known that uncertainty in these coefficients can cause degradation of control performance. In this work, we explore the feasibility of applying...
Stability condition is considered for a class of second-order piecewise linear systems. The state space of the system is divided by partitions into some subsystems. The state trajectory evolves along with the dynamics of the subsystem in which the state exists. A necessary and sufficient condition for the system to be stable is derived. The condition is expressed via the eigenvalues of the matrices...
This paper focusses on the strange nature and qualitative behavior associated with the systems characterized by State Dependent-Delay Differential Equations (SD-DDEs). We consider one of the most simple and innocently looking SD-DDEs x(t) = ±x(t-x(t)). This retarded SD-DDE brings a lot of intricacies. It looks linear but is actually a nonlinear SD-DDE in disguise. It exhibits the phenomenon of bifurcation...
This study concerns the regulation of a simple rigid body mechanical system with dynamic backlash. Contrary to most of the existing works in the control literature we explicitly treat all the non-linear non-smooth characteristics of this system viewed as a rigid body mechanical system with unilateral constraints. We propose a simple PD strategy in order to stabilize the system. For this scheme two...
Nonlinear, adaptive backstepping design is applied to the tracking control problem for a class of strictly passive time-varying systems. The main contribution of this paper is to show that the (time-varying) closed-loop tracking error system has an equilibrium, corresponding to zero steady-state tracking error, that is uniformly globally asymptotically stable (UGAS) and uniformly locally exponentially...
In this paper, the problem of designing sliding mode controls (SMCs) for uncertain time-delay systems is considered. We extend the linear matrix inequality (LMI) approach of Choi [5] to include such systems. Based on the LMI-based method of Choi [5], we get sufficient conditions for the existence of linear sliding surfaces in terms of LMIs, which define convex solution sets, and we show that linear...
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