Simple and robust model predictive control of PMSM with moving horizon estimator for disturbance compensation

This paper deals with a novel robust current control scheme for PMSM drives, based on the model predictive control (MPC) theory. It has been designed a simple quadratic formulation of the reference tracking problem in order to compute the optimal commanded voltage. Considering only equality constraints allows the efficient computation of a closed-form solution which solves the minimisation problem. Authors' proposed objective function is extended to include the inequality constraints, such as current and voltage limitations, therefore, the problem indirectly penalises the violation of boundaries through a weighting strategy. However, the controller does not require any calibration effort, maintaining the application suitable for different drive systems. The increased robustness is achieved through the integration of a moving horizon estimation (MHE), which exploits the same explicit formulation obtained for the MPC, but with the objective of estimating the voltage disturbance affecting the machine. The dual estimation problem is directly integrated within the prediction step of the MPC, improving drastically the local accuracy of the nominal model prediction with further advantages in terms of precise reference tracking and disturbance rejection capabilities. The effectiveness of the proposed control is verified by mean of test-bed experiments

SIOUX project: a simultaneous multiband camera for exoplanet atmospheres studies

The exoplanet revolution is well underway. The last decade has seen order-of-magnitude increases in the number of known planets beyond the Solar system. Detailed characterization of exoplanetary atmospheres provide the best means for distinguishing the makeup of their outer layers, and the only hope for understanding the interplay between initial composition chemistry, temperature-pressure atmospheric profiles, dynamics and circulation. While pioneering work on the observational side has produced the first important detections of atmospheric molecules for the class of transiting exoplanets, important limitations are still present due to the lack of sys- tematic, repeated measurements with optimized instrumentation at both visible (VIS) and near-infrared (NIR) wavelengths. It is thus of fundamental importance to explore quantitatively possible avenues for improvements. In this paper we report initial results of a feasibility study for the prototype of a versatile multi-band imaging system for very high-precision differential photometry that exploits the choice of specifically selected narrow-band filters and novel ideas for the execution of simultaneous VIS and NIR measurements. Starting from the fundamental system requirements driven by the science case at hand, we describe a set of three opto-mechanical solutions for the instrument prototype: 1) a radial distribution of the optical flux using dichroic filters for the wavelength separation and narrow-band filters or liquid crystal filters for the observations; 2) a tree distribution of the optical flux (implying 2 separate foci), with the same technique used for the beam separation and filtering; 3) an exotic solution consisting of the study of a complete optical system (i.e. a brand new telescope) that exploits the chromatic errors of a reflecting surface for directing the different wavelengths at different foci

Amorphous-silicon visible-light detector integrated on silicon nitride waveguides

: Visible-light integrated photonics is emerging as a promising technology for the realization of optical devices for applications in sensing, quantum information and communications, imaging, and displays. Among the existing photonic platforms, high-index-contrast silicon nitride (Si3N4) waveguides offer broadband transparency in the visible spectral range and a high scale of integration. As the complexity of photonic integrated circuits (PICs) increases, on-chip detectors are required to monitor their working point for reconfiguration and stabilization operations. In this Letter, we present a semi-transparent in-line power monitor integrated on Si3N4 waveguides that operates in the red-light wavelength range (660 nm). The proposed device exploits the photoconductivity of a hydrogenated amorphous-silicon (a-Si:H) film that is evanescently coupled to an optical waveguide. Experimental results show a responsivity of 30 mA/W, a sensitivity of -45 dBm, and a sub-µs time response. These features enable the use of the proposed photoconductor for high-sensitivity monitoring and control of visible-light Si3N4 PICs

Robotic treatment of a rare paramedian cystic lesion of the lower male urogenital tract

Abstract Objectives To report the diagnosis and the mini-invasive treatment of a rare paramedian cystic lesion of the lower male urogenital tract (CLMGU). Material and methods This is a case of a 46 old male with low urinary tract symptoms, azoospermia and mild erectile dysfunction. MRI Imaging showed a midline high signal intensity cystic lesion of a tear drop shape, extending above the base of the prostate to the level of the seminal vesicles. The lesion was located between the seminal vesicles and the urinary bladder. A direct communication of the intra-abdominal portion of both vas deferens with the cyst was found. MRI also showed small solid nodule within the upper portion of the cyst. The patient underwent a robotic surgery of the CLMGU. A Retzius-sparing approach was used to gain access to the seminal vesicles in order to carefully dissect and excise the lesion without any dissection of the anterior compartment. The CLMGU was excised with a nerve sparing technique. Results Operative time was 115 min. Blood loss was minimal. Length of stay was three days. No post-operative complications occurred. One month after surgery patient's IPSS improved considerably. Final pathology showed a cystic lesion containing papillary projections with squamous metaplasia. At 2 months follow up, urinary symptoms improved with no postoperative complications. Conclusion Robotic surgery allows a direct access to the Douglas space with an easy removal of the neoplasia. Our video represents a case of possible application of robotic surgery to improve dissection, overall surgical precision and functional outcomes

Comparison of selectivity of a family of chelating agents for trivalent (Al³⁺, Fe³⁺) and bivalent (Cu²⁺, Zn²⁺) metal ions

Chelation therapy is used for the treatment of metal intoxication in humans. Selectivity towards the target metal ion is one important characteristic of the chelating agent. In the frame of our research of chelating agents for iron and aluminium, we synthesized five new ligands (Figure 1), and studied their behavior toward the trivalent metal ions. L4, L5, L6 and L8 were found to be excellent ligands for the coordination of Fe3+ and Al3+. We are presenting here a study on the same ligands with the two essential bivalent metal ions, Zn2+ and Cu2+. The results of spectrophotometric, potentiometric, and NMR measurements performed to determine the equilibrium formation constants will be presented. The speciation of the complexes with the trivalent metal ions in presence of endogenous zinc and copper will be discussed

A three-step approach to patients with suspected acute diverticulitis in the emergency department: An interdisciplinary algorithm proposal

Patients with acute abdominal pain due to acute colonic diverticulitis are a frequent cause of hospital admission. Diverticuar disease increases with age. In Western populations, diverticular disease is diagnosed in 50% individuals over 70 years and 80% over 85 years of age. The identification of patients with acute diverticulitis is a considerable challenge, since numerous other acute abdominal conditions mimic its clinical characteristics. Another problem is the atypical presentation in older patients. A high index of suspicion in the setting of a compatible history and physical examination serves as the cornerstone of early diagnosis. The purpose of this review is to underline the importance of an intimately integrate multidisciplinary approach between emergency physicians, radiologists and surgeons