Condition-based diagnosis of mechatronic systems using a fractional calculus approach

Abstract

While fractional calculus (FC) is as old as integer calculus, its application has been mainly restricted to mathematics. However, many real systems are better described using FC equations than with integer models. FC is a suitable tool for describing systems characterised by their fractal nature, long-term memory and chaotic behaviour. It is a promising methodology for failure analysis and modelling, since the behaviour of a failing system depends on factors that increase the model's complexity. This paper explores the proficiency of FC in modelling complex behaviour by tuning only a few parameters. This work proposes a novel two-step strategy for diagnosis, first modelling common failure conditions and, second, by comparing these models with real machine signals and using the difference to feed a computational classifier. Our proposal is validated using an electrical motor coupled with a mechanical gear reducer.

State Feedback Control Solutions for a Mechatronics System with Variable Moment of Inertia

“…Our SFC solutions can be viewed as a support for other control solutions including fuzzy, neural, sliding mode and adaptive control (Blažič et al, 2010;Precup et al, 2009Precup et al, , 2012Ruano et al, 2002). The performance can be improved by inserting sensitivity, robustness objectives and constraints (Casavola et al, 2014;Gutiérrez-Carvajal et al, 2016). The pole placement method applied in this paper can be replaced by the optimal design and tuning by means of classical or modern optimization algorithms (Bandarabadi et al, 2015;Johanyák, 2015;Menchaca-Mendez and Coello Coello, 2016).…”

Identification of fractional-order transfer functions using exponentially modulated signals with arbitrary excitation waveforms

“…Over the past 20 years there has been a surge in the development of fractional order modelling tools for the emulation of complex processes with greater accuracy compared to conventional integer order representations. This has led to an increased interest in the application of fractional order calculus across all branches of sciences, from biology and medicine [1], [2], [3] to mechatronics [4], [5], [6]. Within the circuits and systems community, new opportunities have arisen for the analysis of complex 2-port networks [7] and passive electrical networks composed of fractional elements [8], [9], which also enabled novel control design solutions with improved stability while using fewer components [10].…”

Detection of structural damage and estimation of reliability using a multidimensional monitoring approach

“…3,4 This type of maintenance strategy allows one to estimate the best time to perform a maintenance task, thus providing the availability of qualified operators, tools for the task and so forth, thereby overall improving the system to which the structure belongs. 5,6…”

“…3,4 This type of maintenance strategy allows one to estimate the best time to perform a maintenance task, thus providing the availability of qualified operators, tools for the task and so forth, thereby overall improving the system to which the structure belongs. 5,6 Railway vehicles are designed to operate for at least 30 years, but real-life conditions present a complex mixture of alternated loads specific to each railway system, 7 such as railway routes, vehicle types, different operational schedules, and maintenance programs amongst others. This could result in early wearing of components, such as cracks and fissures, which requires frequent corrective maintenance tasks and reduces the lifetime of a vehicle, in terms of operation and reliability.…”