Deadlock prevention is a crucial step in the modeling of flexible manufacturing systems. In Petri net framework, deadlock policies based on siphon control are often employed, since it easy to specify generalized mutual exclusion constraints that avoid emptying siphons. However, such may require an excessive computational load and result impractical oversized subnets. This consequence redundancy conditions derived from this paper, novel method proposed provides small size controllers, set...

Abstract Classical prediction error approaches for the identification of non-linear polynomial NARX/NARMAX models often yield unsatisfactory results long-range or simulation purposes, mainly due to incorrect redundant model structure selection. The paper discusses some limitations standard approach and suggests two modifications: namely, a new index, based on error, is employed as regressor selection criterion pruning mechanism introduced in algorithm. resulting algorithm shown be effective...

In Petri-net (PN) modeling of flexible manufacturing systems, deadlock prevention is often addressed by means siphon-control methods. Constraints that avoid the emptying siphons can be easily implemented using additional places suitably connected to PN transitions. Efficient siphon-based techniques achieve highly permissive solutions as few control possible. One such technique employs a set-covering approach optimally match emptiable critical markings. this paper, modified version method...

The characterization of complex air traffic situations is an important issue in management (ATM). Within the current ground-based ATM system, complexity metrics have been introduced with goal evaluating difficulty experienced by controllers guaranteeing appropriate aircraft separation a sector. rapid increase travel demand calls for new generation systems that can safely and efficiently handle higher levels traffic. To this purpose, part responsibility maintenance will be delegated to...

It is widely agreed that future manufacturing environments will be populated by humans and robots sharing the same workspace. However, real collaboration can sporadic, especially in case of assembly tasks, which might involve autonomous operations to executed either robot or human worker. In this scenario, it beneficial predict actions order control both safely efficiently. paper, we propose a method activity patterns early infer when specific collaborative operation requested allow perform...

The novel paradigm of collaborative automation, with machines and industrial robots that synergically share the same workspace human workers, requires to rethink how activities are prioritized in order account for possible variabilities their durations. This article proposes a scheduling method assembly tasks allows optimally plan based on knowledge acquired during runtime so adapts variations along life cycle manufacturing process. scheduler is time Petri nets output optimized by minimizing...

Tire–road friction characteristics are deeply interlaced with all vehicle dynamics control systems, as road conditions strongly affect the schemes behaviour. This work aims at real-time estimation of wheel slip value corresponding to peak tire–road curve, in order provide anti-lock braking systems (ABS) reliable information on its upon activation. Different techniques based recursive least squares and maximum likelihood approach used for curve fitting their merits drawbacks thoroughly...

The paper addresses the problem of enumerating minimal siphons in an ordinary Petri net. algorithms developed this work recursively use a partitioning procedure to reduce original search multiple simpler subproblems. Each subproblem has specific additional place constraints with respect problem. Some results on algorithm correctness, convergence, and computational complexity are provided, as well experimental evaluation performance. can be applied enumerate minimal, place-minimal siphons, or...

Most approaches for deadlock prevention and liveness enforcement in Petri nets rely on siphon control methods or the theory of regions to derive monitor-based supervisors. These techniques raise methodological computational issues, from existence feasible solutions hardness guaranteeing maximal permissivity optimality size cost subnet. Recently, supervisor design problem has also been reformulated as a direct monitor optimization task based integer linear programming, which can more...

In non-linear model identification the problem of structure selection is critical for success process. This paper discusses this with reference to class polynomial NARX models. First it shown that classical approaches based on (one-step-ahead) Prediction Error Minimisation (PEM) may lead an incorrect or redundant selection, especially in non-ideal conditions where data are not adequately exciting over-sampled. Then a more effective approach introduced, minimisation simulation (or prediction)...

The extension of active noise control (ANC) techniques to deal with nonlinear effects such as distortion and saturation requires the introduction suitable model classes adaptive algorithms. Large sized models are typically used, resulting in an increased computational load, delayed convergence (and sometimes even algorithm instability), other unwanted dynamical due overparametrization. This paper discusses usage polynomial autoregressive exogenous variables (NARX) selection reduce size...

The simulation error minimisation (SEM) approach is very effective for polynomial non-linear autoregressive with exogenous variables (NARX) model selection, but typically limited to the exploration of candidate regressor sets size because computational cost involved in and complexity empirical structure selection process over large sets. This study investigates combination a SEM algorithm known as pruning (SEMP), least absolute shrinkage operator, which operates regularisation that balances...

A recent line of work has sought the implementation maximally permissive deadlock avoidance policy (DAP) for a broad class complex resource allocation systems (RAS) as classifier that gives effective and parsimonious representation to dichotomy underlying behavioral space into admissible inadmissible subspaces defined by policy. The presented in this paper complements past developments area providing 1) succinct conditions regarding possibility expressing aforementioned set linear...

Future production plants will see more and the presence of humans actively collaborating with robots. Typical scenarios are those related to assembly lines. In such contexts behaviour is not controllable. Therefore problem produce a scheduling for robotic activities accounting predicted human intentions. this work we propose strategy based on Time Petri Nets. The sequence commands scheduled robot executed exploiting receding horizon principle. developed approach applied realistic use-case,...

DNA microarray datasets are characterized by a large number of features with very few samples, which is typical cause overfitting and poor generalization in the classification task. Here, we introduce novel feature selection (FS) approach employs distance correlation (dCor) as criterion for evaluating dependence class on given subset. The dCor index provides reliable measure among random vectors arbitrary dimension, without any assumption their distribution. Moreover, it sensitive to...

This paper presents a methodology for identifying variable-structure nonlinear models of magneto-rheological dampers (MRD) and similar devices. Its peculiarity with respect to the mainstream literature is be especially conceived obtaining that are structurally simple, easy estimate well suited model-based control. goal pursued by adopting linear-in-the-parameters NARX models, which an identification method developed based on minimization simulation error. capable selecting model structure...