Optical feedback interferometry (OFI) sensors are experiencing a consistent increase in their applications to biosensing due to their contactless nature, low cost and compactness, features that fit very well with current biophotonics research and market trends. The present paper is a review of the work in progress at UPC-CD6 and LAAS-CNRS related to the application of OFI to different aspects of biosensing, both in vivo and ex vivo. This work is intended to present the variety of opportunities and potential applications related to OFI that are available in the field. The activities presented are divided into two main sensing strategies: The measurement of optical path changes and the monitoring of flows, which correspond to sensing strategies linked to the reconstruction of changes of amplitude from the interferometric signal, and to classical Doppler frequency measurements, respectively. For optical path change measurements, measurements of transient pulses, usual in biosensing, together with the measurement of large displacements applied to designing palliative care instrumentation for Parkinson disease are discussed. Regarding the Doppler-based approach, progress in flow-related signal processing and applications in real-time monitoring of non-steady flows, human blood flow monitoring and OFI pressure myograph sensing will be presented. In all cases, experimental setups are discussed and results presented, showing the versatility of the technique. The described applications show the wide capabilities in biosensing of the OFI sensor, showing it as an enabler of low-cost, all-optical, high accuracy biomedical applications.

We present a Shack-Hartmann wavefront sensor (SHWS) based on a cylindrical microlens array as a device for measuring highly aberrated wavefronts. Instead of the typical spot pattern created by a conventional SHWS, two orthogonal line patterns are detected on a CCD and are superimposed. A processing algorithm uses the continuity of the focal line to extend the dynamic range of measurement by localizing the line, even if it leaves the CCD area confined by the corresponding microcylinder. The measurement of a wavefront from a progressive addition lens with an 80 lambda peak-to-valley value reveals the capabilities of the sensor.

Permanent magnet synchronous machines (PMSM) are widely used in the automotive industry for electric vehicle (EV) and hybrid electric vehicle (HEV) propulsion systems, where the trend is to achieve high mechanical speeds. High speeds inevitably imply high current electrical frequencies, which can lead to a lack of controllability when using field oriented control (FOC) due to sampling period constraints. In this work, a comprehensive discrete-time model is fully developed to assess the stability issues in the widely used FOC. A speedadaptive control structure that overcomes these stability problems and extends the speed operation range of the PMSM is presented. Also, a numerical methodology from which the maximum operating stable frequency can be computed in advance of any experimentation, is developed. All contributions are accompanied and supported by numerical results obtained from an accurate MATLAB/Simulink model.

Abstract. We present a method of measure of the roughness of the paper based on the analysis of a speckle pattern on the surface. Images of speckle over the surface of paper are captured by means of a simple configuration using a laser, beam expander, and a camera chargecoupled device (CCD). Then we use the normalized covariance function of the fields, leaving the surface to find the roughness. We compare the results obtained with the results obtained with a confocal microscope and the Bendtsen method that is a standard of the paper industry. This method can be considered as a noncontact surface profiling method that can be used online. C 2011 Society of Photo-Optical Instrumentation Engineers (SPIE).

This paper pursues to maximise the mechanical speed when using stepping motors (SM) without position sensors in order to achieve a rapid-response manufacturing whenever any equipment based on such electrical machines is involved. The novelty of this paper is the fact that not only the bandwidth of the current controllers is improved for such maximization of the SM mechanical speed, as traditionally done in previous works, but also a comprehensive approach has been addressed. Such global approach starts justifying why the traditional PI controller is not sufficient and it includes the analytical tuning of the current controllers, considering implementation tiny issues (but of paramount importance) such as the delays caused by the processor and the sample and hold current measurements. It is proved and justified that this previously mentioned issues, which are often omitted, play a crucial role when trying to maximise the speed of the SM, since the electrical fundamental frequencies of the SM move close to the sampling frequency. Therefore, the analytical process to tune and implement the current controllers will have to be done in discrete-time domain, i.e. using the Z transform and treating the SM drive as a sampled data system. Experimental waveforms and results based on real prototypes will prove the validity of the entire research. Finally, a real case-study based on Printed Circuit Board (PCB) prototyping machine which is composed by two stepper machines, is fully reported. Such PCB prototype is the fruitful collaboration between the University (research institution) and a private company (industry). © 2016 Elsevier LtdPeer ReviewedPostprint (author's final draft