Stefania Santini

Distributed Consensus Strategy for Platooning of Vehicles in the Presence of Time-Varying Heterogeneous Communication Delays

We analyze and solve the platooning problem by treating it as the problem of achieving consensus in a network of dynamical systems affected by time-varying heterogeneous delays due to wireless communication among vehicles. Specifically, a platoon is modeled as a dynamical network where: 1) each vehicle, with its own dynamics, is a node; 2) the presence of communication links between neighboring vehicles is represented by edges; and 3) the structure of the intervehicle communication is encoded in the network topology. A distributed control protocol, which acts on every vehicle in the platoon, is derived. It is composed of two terms: a local action depending on the state variables of the vehicle itself (measured onboard) and an action depending on the information received from neighboring vehicles through the communication network. The stability of the platoon is proven by using Lyapunov-Razumikhin theorem. Numerical results are included to confirm and illustrate the theoretical derivation.

Hybrid Model Reference Adaptive Control of Piecewise Affine Systems

This paper is concerned with the derivation of a model reference adaptive control (MRAC) scheme for multimodal piecewise-affine (PWA) and piecewise-linear systems. The control allows the plant to track asymptotically the states of a multimodal piecewise affine (or smooth) reference model. The reference model can be characterized by a number and geometry of phase space regions that can be entirely different from those of the plant. Numerical simulations on a set of representative examples confirm the theoretical derivation and proof of stability.

Synthesis and Experimental Validation of the Novel LQ-NEMCSI Adaptive Strategy on an Electronic Throttle Valve

This paper is concerned with the design of a novel adaptive controller, namely the linear quadratic new extended minimal control synthesis with integral action (LQ-NEMCSI). We present for the first time the analytical proof of asymptotic stability of the controller and experimental evidence of the algorithm effectiveness for controlling an electronic throttle body: an element of any drive-by-wire system in automotive engineering, affected by many nonlinear perturbations.

Minimal Control Synthesis Adaptive Control of Continuous Bimodal Piecewise Affine Systems

This paper reviews the derivation of a model reference adaptive control (MRAC) scheme for bimodal piecewise-affine (PWA) continuous systems [9]. The algorithm is based on an extension of the minimal control synthesis algorithm, originally developed as an MRAC for smooth systems. The resulting adaptive algorithm is a switched feedback controller able to cope with uncertain continuous PWA systems. The effectiveness of the new proposed control strategy is shown by using it to achieve master slave synchronization of two PWA systems as a representative example.

How to Turn a Genetic Circuit into a Synthetic Tunable Oscillator, or a Bistable Switch

Systems and Synthetic Biology use computational models of biological pathways in order to study in silico the behaviour of biological pathways. Mathematical models allow to verify biological hypotheses and to predict new possible dynamical behaviours. Here we use the tools of non-linear analysis to understand how to change the dynamics of the genes composing a novel synthetic network recently constructed in the yeast Saccharomyces cerevisiae for In-vivo Reverse-engineering and Modelling Assessment (IRMA). Guided by previous theoretical results that make the dynamics of a biological network depend on its topological properties, through the use of simulation and continuation techniques, we found that the network can be easily turned into a robust and tunable synthetic oscillator or a bistable switch. Our results provide guidelines to properly re-engineering in vivo the network in order to tune its dynamics.

Novel switched model reference adaptive control for continuous piecewise affine systems

This paper is concerned with the derivation of a novel model reference adaptive control (MRAC) scheme for piecewise-affine (PWA) continuous systems. A novel version of the minimal control synthesis algorithm, originally developed as a MRAC for smooth systems, is presented. The resulting adaptive algorithm is a switched feedback controller able to cope with uncertain continuous PWA systems. The proof of stability, based on the newly developed passivity theory for hybrid systems, is provided and the effectiveness of the new proposed control strategy is numerically tested.

Corner-Impact Bifurcations: A Novel Class of Discontinuity-Induced Bifurcations in Cam-Follower Systems

This paper is concerned with the analysis of a class of impacting systems of relevance in applications: cam-follower systems. We show that these systems, which can be modeled as discontinuously forced impact oscillators, can exhibit complex behavior due to the detachment at high rotational speeds between the follower and the cam. We propose that the observed phenomena can be explained in terms of a novel type of discontinuity-induced bifurcation, termed as corner-impact. We present a complete analysis of this bifurcation in the case of a nonautonomous impact oscillator and explain the transition to chaos observed in a representative cam-follower example. The theoretical findings are validated numerically.

Canonical Forms of Generic Piecewise Linear Continuous Systems

This technical note reports a simple, but effective strategy to derive a single coordinate transformation of a generic n-dimensional piecewise-linear continuous vector field that puts both of its subsystems into the same observer or control canonical form. The only hypothesis required is that both subsystems are either observable or controllable. To derive the result, the structure of the system is used in order to prove that it suffices to consider the same transformation for both subsystems. The theoretical results are illustrated by means of the Colpitts oscillator as a practical case of study.

Torque generation model for diesel engine

In this paper a combustion model of direct injection diesel engine is proposed to calculate the in-cylinder pressure and a crank-slider mechanism model to calculate instantaneous indicated torque. The crankshaft is modelled as a rigid body. The parameters of both models are identified via non-linear least square optimization algorithm. The data, used for the identification procedure, are purposely obtained through experiments on a diesel turbocharged BMW MD47 1900cc with a dynamic test-bench.

Novel hybrid MRAC-LQ control schemes: synthesis, analysis and applications

LQ optimal controllers are widely used in many applications as they provide a simple and effective solution to optimal control problems. There are many examples in the literature that show the lack of robustness of such controllers when the process is subject to parameter variations or when some dynamics are neglected. The hybrid algorithms proposed in this work extend the family of model reference minimal control synthesis adaptive controllers and address the issue of enhancing the robustness of LQ regulators. The main idea behind the approach is to seek a simple and alternative route to implement the LQ regulator via the MCS algorithm which is effective also in those practical cases when the LQ action itself fails. The stability of all the proposed control schemes is proved and the performance on a set of representative examples shows the effectiveness of the approach.