Stabilising Model Predictive Control for Discrete-time Fractional-order Systems

In this paper we propose a model predictive control scheme for constrained fractional-order discrete-time systems. We prove that all constraints are satisfied at all time instants and we prescribe conditions for the origin to be an asymptotically stable equilibrium point of the controlled system. We employ a finite-dimensional approximation of the original infinite-dimensional dynamics for which the approximation error can become arbitrarily small. We use the approximate dynamics to design a tube-based model predictive controller which steers the system state to a neighbourhood of the origin of controlled size. We finally derive stability conditions for the MPC-controlled system which are computationally tractable and account for the infinite dimensional nature of the fractional-order system and the state and input constraints. The proposed control methodology guarantees asymptotic stability of the discrete-time fractional order system, satisfaction of the prescribed constraints and recursive feasibility

Decibell: A novel approach to the ORM software in Java

DeciBell is an open source and free tool developed to tackle in a uniform and structured way the problem of Java and SQL cooperation (available at http://github.com/hampos/DeciBell). In DeciBell, Java classes are related to relational database entities automatically and in a transparent way as far as the background operations are concerned. So, on one hand, non-expert users can work on Java code exclusively while expert ones are able to focus on more algorithmic aspects of the problem they try to solve rather than be wasted with trivial database management issues. In contrast to the existing O.R.M. programs, DeciBell does not require any configuration files or composite query structures, but only a proper annotation of certain fields of the classes. This annotation is carried out by means of the Java Annotations which is a modern trend in Java programming. Among its supported facilities, DeciBell supports primary keys (single and multiple), foreign keys, constraints, one-to-one, one- to-many, and many-to-many relations and all these using pure Java predicates and no SQL or other Query Languages

Controlled drug administration by a fractional PID

Amiodarone is an antiarrhythmic drug that exhibits highly complex and non-exponential dynamics whose controlled administration has important implications for its clinical use especially for long-term therapies. Its pharmacokinetics has been accurately modelled using a fractional-order compartmental model. In this paper we design a fractional-order PID controller and we evaluate its dynamical characteristics in terms of the stability margins of the closed loop and the ability of the controlled system to attenuate various sources of noise and uncertainty

A Simple and Efficient Algorithm for Nonlinear Model Predictive Control

We present PANOC, a new algorithm for solving optimal control problems arising in nonlinear model predictive control (NMPC). A usual approach to this type of problems is sequential quadratic programming (SQP), which requires the solution of a quadratic program at every iteration and, consequently, inner iterative procedures. As a result, when the problem is ill-conditioned or the prediction horizon is large, each outer iteration becomes computationally very expensive. We propose a line-search algorithm that combines forward-backward iterations (FB) and Newton-type steps over the recently introduced forward-backward envelope (FBE), a continuous, real-valued, exact merit function for the original problem. The curvature information of Newton-type methods enables asymptotic superlinear rates under mild assumptions at the limit point, and the proposed algorithm is based on very simple operations: access to first-order information of the cost and dynamics and low-cost direct linear algebra. No inner iterative procedure nor Hessian evaluation is required, making our approach computationally simpler than SQP methods. The low-memory requirements and simple implementation make our method particularly suited for embedded NMPC applications