This paper develops a new active fault tolerant control system based on the concept of analytical redundancy. The novel design consists of an observation filter based fault detection and identification system integrated with a nonlinear model predictive controller. A number of observation filters were designed, integrated with the nonlinear controller and tested before reaching the final design which comprises an unscented Kalman filter for fault detection and identification together with a nonlinear model predictive controller to form an active fault tolerant control system design.

This paper addresses the classical problem of determining the set of possible states of a linear discrete-time SISO system subject to bounded disturbances, from measurements corrupted by bounded noise. These so-called uncertainty sets evolve with time as new measurements become available. We present two theorems which give a complete description of the relationship between uncertainty sets at two successive time instants, and this yields an efficient algorithm for recursively updating uncertainty sets. Numerical simulations demonstrate performance improvements over existing exact methods.

In [7] there are new results concerning the poly-topic set of possible states of a linear discrete-time SISO system subject to bounded disturbances from measurements corrupted by bounded noise. Using these results we construct an algorithm which, for the special case of a plant with a lag, recursively updates these polytopic sets when new measurements arrive.

In this paper we investigate the design of an active fault tolerant control system applicable to autonomous flight. The system comprises a nonlinear model predictive based controller integrated with an unscented Kalman filter for fault detection and identification. We apply the fault tolerant control system design to a generic aircraft model, and simulate a failed engine scenario. The results show that the system correctly identifies the fault within seconds of occurrence and updates the nonlinear model predictive controller which is then able to reallocate control authority to the healthy actuators based upon up to date fault information.

This paper addresses the classical problem of determining the set of possible states of a linear discrete-time system subject to bounded disturbances from measurements corrupted by bounded noise. These so-called uncertainty sets evolve with time as new measurements become available. We present two theorems which describe completely how they evolve with time, and this yields an efficient algorithm for recursively updating uncertainty sets. Numerical simulations demonstrate performance improvements over existing exact methods.

This paper describes the design process for developing a nonlinear model predictive controller for fault tolerant flight control. After examining and implementing a number of numerical techniques, this paper identifies pseudospectral discretisation as the most suitable for this design. Applying the controller to a 2D robot model shows that the nonlinear controller performs much better than the linear controller, especially in the closed loop scenario. Assuming fault detection information, applying the technique to the longitudinal motion of a generic aircraft model shows the design to be eminently suitable for flight control.

This paper develops a new active fault tolerant control system based on the concept of analytical redundancy. The novel design consists of an observation filter based fault detection and identification system integrated with a nonlinear model predictive controller. A number of observation filters were designed, integrated with the nonlinear controller and tested before reaching the final design which comprises an unscented Kalman filter for fault detection and identification together with a nonlinear model predictive controller to form an active fault tolerant control system design.

In this paper we describe some properties of companion matrices and demonstrate some special patterns that arisewhen a Toeplitz or a Hankel matrix is multiplied by a related companion matrix.We present a necessary and sufficient condition, generalizing known results, for a matrix to be the transforming matrix for a similarity between a pair of companion matrices. A special case of our main result shows that a Toeplitz or a Hankel matrix can be extended using associated companion matrices, preserving the Toeplitz or Hankel structure respectively.

This paper addresses the classical problem of determining the sets of possible states of a linear discrete-time system subject to bounded disturbances from measurements corrupted by bounded noise. These so-called uncertainty sets evolve with time as new measurements become available. We present an exact, computationally simple procedure that propagates a point on the boundary of the uncertainty set at some time instant to a set of points on the boundary of the uncertainty set at the next time instant.

In this paper we illustrate some new ideas in the theory of l1–norm minimisation. A simple looking mathematical programming problem, namely the minimisation of the sum of the one norms of two signals connected by convolution constraints, is investigated. This describes an l1 model matching problem for which there are no zero interpolation conditions, and just one rank interpolation condition. Despite its apparent simplicity, finding exact solutions for this problem is a challenging task. We extend the class of problems for which exact optimal solutions can be found by combining a primal/dual formulation with dynamic programming ideas. These solutions have the desirable feature of yielding a control law in feedback form.

We take the inverse of a Sylvester matrix of two coprime polynomials of degree m and study the family of m×m submatrices formed from consecutive columns of the bottom m rows. We prove that these matrices commute and in the course of the proof we find a similar relation for Bezoutian matrices related to the polynomials.

In this note we discover and prove some interesting and important relations among sub-matrices of Sylvester matrices and triangular toeplitz matrices. The main result is Hill's identity discovered by R. D. Hill which has an important application in optimal control problems.

A dual formulation for the problem of determining absolute performance limitations on overshoot, undershoot, maximum amplitude and fluctuation minimization for continuous-time feedback systems is constructed. Determining, for example, the minimum possible overshoot attainable by all possible stabilizing controllers is an optimization task that cannot be expressed as a minimum-norm problem. It is this fact, coupled with the continuous-time rather than discrete-time formulation, that makes these problems challenging. We extend previous results to include more general reference functions, and derive new results (in continuous time) on the influence of pole/zero locations on achievable time-domain performance.

A design for a reconfigurable fault tolerant flight control system for an unmanned air vehicle has been proposed in this paper. Due to the severe nonlinearities inherent in an aircraft system Non-Linear Model Predictive Control has been chosen for the controller design. The results obtained show good aircraft performance in the event of a control surface failure.

The solution to a basic problem in time-invariant l1 optimal control is constructed in feedback form. Using ideas from dynamic programming and duality, we find the rule describing how, for optimal l1 regulation, the state at any time instant is to be mapped to the state at the next time instant. This mapping is a function of the state alone and, much like the optimal gain matrix for linear quadratic control, can be computed before system operation.

Existing design methodologies based on infinite-dimensional linear programming generally require an iterative process often involving progressive increase of truncation length, in order to achieve a desired accuracy. In this chapter we consider the fundamental problem of determining a priori estimates of the truncation length sufficient for attainment of a given accuracy in the optimal objective value of certain infinite-dimensional linear programs arising in optimal feedback control. The treatment here also allows us to consider objective functions lacking interiority of domain, a problem which often arises in practice.

The topic of this paper is the discrete-time l1-norm minimisation problem with convolution constraints. We find primal initial conditions for which the dual optimal solution is periodic. Periodicity of the dual optimal solution implies satisfaction of a simple linear recurrence relation by the primal optimal solution.

We explore an optimization problem which arises naturally in the design of feedback controllers to achieve optimal robustness. Stated mathematically, the problem imposes an $l_{1}$-norm objective on the input and output signals of a linear discrete-time dynamic system. Recently I presented an algorithm which systematically determines initial conditions for which exact solutions can be found. The contribution of this article is twofold. Firstly, we illustrate the usefulness of the algorithm in understanding optimal dynamic response for a specific example. Secondly, we investigate the apparent disappearance of an attracting periodic point as an input data parameter is varied. I conjecture that the dynamic evolution of optimal solutions may exhibit chaos.

The development of a fuzzy logic controller on a new configuration of ducted-fan VTOL UAV is presented for automating the transition manoeuvre. The design goal is to have a smooth push-over transition flight from low speed vertical flight to high speed horizontal flight in the presence of wind disturbance and without the need of using complicated control strategies. A target attitude for the transition is selected and then compared with the current vehicle attitude. This gives the attitude errors that are used to generate command signals to the vehicle controller. Simulation results demonstrate that the UAV was able to perform a smooth transition manoeuvre and has a good overall performance.