Theoretical und experimental investigation of a permanent magnet excited transverse flux synchronous linear motor by special construction

In dieser Arbeit wurde ein permanentmagneterregter, synchroner Linearantrieb mit Transversalflusskonzept in Sonderbauform behandelt. Dieser synchrone TFM-Linearmotor weist eine hohe Vorschubkraft und sehr spezielle Bauweise auf. Zur Überprüfung der theoretischen Berechnungen wurde ein Prototyp mit Transversalflusskonzept ausgelegt und aufgebaut. Gemäß theoretischen Berechnungen und nach experimentellen Untersuchungen konnte nachgewiesen werden, dass der entwickelte synchrone TFM-Linearmotor gemäß vorgestellter Funktions- und Bauweise für Handhabungsaufgaben in industrieller Anwendung eingesetzt werden kann. Die Minimierung der Rastkraft ist eine wichtige Aufgabe bei der Entwicklung dieses PM-Linearantriebs. Die Techniken zur Reduzierung der Rastkraft wurden vorgestellt. Eine Methode zur Reduzierung der Rastkraft wurde in dieser Arbeit zur Anwendung gebracht, wobei die geometrische Zuordung zwischen Permanentmagneten und Translator betrachtet wurde, um eine einfache Fertigung der Maschine zu gewährleisten. Deshalb spielt die Bestimmung der Translatorpolteilung τR eine zentrale Rolle. Eine ungünstige Wahl der Translatorpolteilung kann eine große Rastkraft verursachen. Die Translatorpolteilung wurde zunächst für experimentelle Untersuchungen jeweils zu 17,5 mm (= 5τM /6) und 28,0 mm (= 4τM /3) bestimmt, wobei τR = 17,5 mm die bessere Wahl darstellt. Wegen des Abbruchs von Material von einigen Zahnköpfen bei der erstmaligen Montage des Translators (τR=17,5mm) ist die Translatorpolteilung nachträglich auf 28,0 mm festgesetzt worden. Diese ungeeignete Translatorpolteilung führt zu einer höheren Rastkraft. Um die Rastkraft auf weniger als 5 N zu reduzieren, wird vorgeschlagen, für die Translatorpolteilung 5τM /6 zu wählen. Das Ergebnis bestätigt sich, dass ein direkter Linearantrieb nach dem vorgestellten Transversalflusskonzept eine hohe Vorschubkraft von ca. 290 N erzielen kann. Die Antriebskraft des synchronen TFM-Linearmotors könnte nach Erhöhung der Remanenz des Permanentmagnetmaterials (bisher Br=1,05 T), bei vollständiger Kraftwirkfläche des Zahnkopfs (Verbesserung des Fertigungsprozesses) sowie ohne Feldabfall zwischen den Einzelmagneten (Blockpolmagnet statt Einzelpolmagnete) weiter erhöht werden. Durch die experimentellen Untersuchungen sind die Betriebsdaten und Kennlinien des synchronen TFM-Linearmotors bestätigt worden. Aufgrund der begrenzten Hublänge von nur 188,0 mm konnten die Daten und Kennlinien nur mit einer Betriebsgeschwindigkeit bis 0,63 m/s aufgenommen werden. Gemäß den Messergebnissen weist der synchrone TFM-Linearmotor einen guten Wirkungsgrad und einen guten Leistungsfaktor auf.A permanent magnet(PM) excited synchronous linear device with transverse flux concept(TFM linear motor) in a special form was studied in this dissertation. This synchronous TFM linear motor shows a high thrust and very special construction. In order to check the theoretical calculation, a prototype was designed and built. According to theoretical calculation and experimental investigation, it could be proved that the developed TFM linear motor can be used in industrial operation. The minimization of the cogging force is an important task in the development of this PM TFM linear motor. Techniques to minimize the cogging force were introduced. One of the techniques was applied in this dissertation. In order to guarantee the simple manufacturing of the machine, the arrangement between the permanent magnet pole pitch τM and the translator pole pitch τR was considered. Therefore, the determination of τR plays a central role. An unsuitable selection of τR can create a large cogging force. For experimental investigation the translator pole pitch was set at 17.5 mm (= 5τM /6) and 28.0 mm (= 4M /3) respectively, of which τR = 17.5 mm is the better choice. Because of damage of the tooth head at the translator during the first mounting (τR = 17.5 mm) of the motor, the translator pole pitch was fixed at 28.0 mm. But, this unsuitable selection created a higher cogging force. The test result has confirmed that a directly operated linear motor according to introduced transverse flux concept can achieve a high thrust of about 290 N. This thrust of the synchronous TFM linear motor can be further increased by higher remanence of permanent magnet (till now Br=1.05 T), a fully effective area of tooth head to create thrust (i.e. improving the manufacturing process) and without field reduction between the single permanent magnets (using block pole magnets instead of single pole magnets). The operation data and characteristic curve of the synchronous TFM linear motor were confirmed by experimental investigation. Due to the limited drive length only for 188.0 mm, this data and characteristic curve could only be obtained up to a drive speed of 0.63 m/s. Results show that the synchronous TFM linear motor features a good efficiency and power factor

Using Taguchi’s method to minimize cogging force of a PM transverse flux linear motor

Cogging force accounts for important downsides in several aspects, namely causing the speed ripples, inducing vibrations and noises, and increasing the difficulty of position control. All of these negative affects will become more obvious, particularly under light loads and low speeds. So if the cogging force can be kept as minimal as possible, or even completely disappeared, the operational performance of motors will be improved significantly. As our preliminary study indicates, the magnitude of cogging force is influenced by construction of motors, which govern a number of motor parameters. In this paper, the cogging force of a novel type of permanent magnet excited transverse flux linear synchronous motor will be minimized in two steps. First, theoretical analysis will be employed to obtain the most influential parameter on cogging force. Second, Taguchi’s method including 2D finite element analysis is applied to minimize the cogging force. Analytical and simulation results indicate the usefulness of our approach in practice

Cogging Torque Reduction of Interior Permanent-Magnet Synchronous Motors by Finite-Element Method

The cogging torque of a permanent-magnet motor is an oscillatory torque that always induces vibration, acoustic noise, possible resonance and speed ripples, and its minimization is a major concern for electric motor designers. This paper presents an effective approach for the cogging torque reduction of interior permanent-magnet motors by modifying the magnet span angle of the rotor and the shoe depth and shoe ramp of the stator. The cogging torque is calculated by employing a commercial finite-element analysis software Ansoft/Maxwell. The results show that the peak value of the cogging torque for the modified design decreases 50% in comparison with that of the original design

Benchmarking of eight recurrent neural network variants for breath phase and adventitious sound detection on a self-developed open-access lung sound database-HF_Lung_V1

A reliable, remote, and continuous real-time respiratory sound monitor with automated respiratory sound analysis ability is urgently required in many clinical scenarios-such as in monitoring disease progression of coronavirus disease 2019-to replace conventional auscultation with a handheld stethoscope. However, a robust computerized respiratory sound analysis algorithm has not yet been validated in practical applications. In this study, we developed a lung sound database (HF_Lung_V1) comprising 9,765 audio files of lung sounds (duration of 15 s each), 34,095 inhalation labels, 18,349 exhalation labels, 13,883 continuous adventitious sound (CAS) labels (comprising 8,457 wheeze labels, 686 stridor labels, and 4,740 rhonchi labels), and 15,606 discontinuous adventitious sound labels (all crackles). We conducted benchmark tests for long short-term memory (LSTM), gated recurrent unit (GRU), bidirectional LSTM (BiLSTM), bidirectional GRU (BiGRU), convolutional neural network (CNN)-LSTM, CNN-GRU, CNN-BiLSTM, and CNN-BiGRU models for breath phase detection and adventitious sound detection. We also conducted a performance comparison between the LSTM-based and GRU-based models, between unidirectional and bidirectional models, and between models with and without a CNN. The results revealed that these models exhibited adequate performance in lung sound analysis. The GRU-based models outperformed, in terms of F1 scores and areas under the receiver operating characteristic curves, the LSTM-based models in most of the defined tasks. Furthermore, all bidirectional models outperformed their unidirectional counterparts. Finally, the addition of a CNN improved the accuracy of lung sound analysis, especially in the CAS detection tasks.Comment: 48 pages, 8 figures. To be submitte

“Cell Biology Meets Physiology

The immunological synapse (IS) is an excellent example of cell-cell communication, where signals are exchanged between two cells, resulting in a well-structured line of defense during adaptive immune response. This process has been the focus of several studies that aimed at understanding its formation and subsequent events and has led to the realization that it relies on a well-orchestrated molecular program that only occurs when specific requirements are met. The development of more precise and controllable T cell activation systems has led to new insights including the role of mechanotransduction in the process of formation of the IS and T cell activation. Continuous advances in our understanding of the IS formation, particularly in the context of T cell activation and differentiation, as well the development of new T cell activation systems are being applied to the establishment and improvement of immune therapeutical approaches

"Cell biology meets physiology: functional organization of vertebrate plasma membranes"--the immunological synapse.

The immunological synapse (IS) is an excellent example of cell-cell communication, where signals are exchanged between two cells, resulting in a well-structured line of defense during adaptive immune response. This process has been the focus of several studies that aimed at understanding its formation and subsequent events and has led to the realization that it relies on a well-orchestrated molecular program that only occurs when specific requirements are met. The development of more precise and controllable T cell activation systems has led to new insights including the role of mechanotransduction in the process of formation of the IS and T cell activation. Continuous advances in our understanding of the IS formation, particularly in the context of T cell activation and differentiation, as well the development of new T cell activation systems are being applied to the establishment and improvement of immune therapeutical approaches

Efficacy and safety of sparsentan versus irbesartan in patients with IgA nephropathy (PROTECT): 2-year results from a randomised, active-controlled, phase 3 trial

BackgroundSparsentan, a novel, non-immunosuppressive, single-molecule, dual endothelin angiotensin receptor antagonist, significantly reduced proteinuria versus irbesartan, an angiotensin II receptor blocker, at 36 weeks (primary endpoint) in patients with immunoglobulin A nephropathy in the phase 3 PROTECT trial's previously reported interim analysis. Here, we report kidney function and outcomes over 110 weeks from the double-blind final analysis.MethodsPROTECT, a double-blind, randomised, active-controlled, phase 3 study, was done across 134 clinical practice sites in 18 countries throughout the Americas, Asia, and Europe. Patients aged 18 years or older with biopsy-proven primary IgA nephropathy and proteinuria of at least 1·0 g per day despite maximised renin–angiotensin system inhibition for at least 12 weeks were randomly assigned (1:1) to receive sparsentan (target dose 400 mg oral sparsentan once daily) or irbesartan (target dose 300 mg oral irbesartan once daily) based on a permuted-block randomisation method. The primary endpoint was proteinuria change between treatment groups at 36 weeks. Secondary endpoints included rate of change (slope) of the estimated glomerular filtration rate (eGFR), changes in proteinuria, a composite of kidney failure (confirmed 40% eGFR reduction, end-stage kidney disease, or all-cause mortality), and safety and tolerability up to 110 weeks from randomisation. Secondary efficacy outcomes were assessed in the full analysis set and safety was assessed in the safety set, both of which were defined as all patients who were randomly assigned and received at least one dose of randomly assigned study drug. This trial is registered with ClinicalTrials.gov, NCT03762850.FindingsBetween Dec 20, 2018, and May 26, 2021, 203 patients were randomly assigned to the sparsentan group and 203 to the irbesartan group. One patient from each group did not receive the study drug and was excluded from the efficacy and safety analyses (282 [70%] of 404 included patients were male and 272 [67%] were White) . Patients in the sparsentan group had a slower rate of eGFR decline than those in the irbesartan group. eGFR chronic 2-year slope (weeks 6–110) was −2·7 mL/min per 1·73 m2 per year versus −3·8 mL/min per 1·73 m2 per year (difference 1·1 mL/min per 1·73 m2 per year, 95% CI 0·1 to 2·1; p=0·037); total 2-year slope (day 1–week 110) was −2·9 mL/min per 1·73 m2 per year versus −3·9 mL/min per 1·73 m2 per year (difference 1·0 mL/min per 1·73 m2 per year, 95% CI −0·03 to 1·94; p=0·058). The significant reduction in proteinuria at 36 weeks with sparsentan was maintained throughout the study period; at 110 weeks, proteinuria, as determined by the change from baseline in urine protein-to-creatinine ratio, was 40% lower in the sparsentan group than in the irbesartan group (−42·8%, 95% CI −49·8 to −35·0, with sparsentan versus −4·4%, −15·8 to 8·7, with irbesartan; geometric least-squares mean ratio 0·60, 95% CI 0·50 to 0·72). The composite kidney failure endpoint was reached by 18 (9%) of 202 patients in the sparsentan group versus 26 (13%) of 202 patients in the irbesartan group (relative risk 0·7, 95% CI 0·4 to 1·2). Treatment-emergent adverse events were well balanced between sparsentan and irbesartan, with no new safety signals.InterpretationOver 110 weeks, treatment with sparsentan versus maximally titrated irbesartan in patients with IgA nephropathy resulted in significant reductions in proteinuria and preservation of kidney function

Sparsentan in patients with IgA nephropathy: a prespecified interim analysis from a randomised, double-blind, active-controlled clinical trial

Background: Sparsentan is a novel, non-immunosuppressive, single-molecule, dual endothelin and angiotensin receptor antagonist being examined in an ongoing phase 3 trial in adults with IgA nephropathy. We report the prespecified interim analysis of the primary proteinuria efficacy endpoint, and safety. Methods: PROTECT is an international, randomised, double-blind, active-controlled study, being conducted in 134 clinical practice sites in 18 countries. The study examines sparsentan versus irbesartan in adults (aged ≥18 years) with biopsy-proven IgA nephropathy and proteinuria of 1·0 g/day or higher despite maximised renin-angiotensin system inhibitor treatment for at least 12 weeks. Participants were randomly assigned in a 1:1 ratio to receive sparsentan 400 mg once daily or irbesartan 300 mg once daily, stratified by estimated glomerular filtration rate at screening (30 to 1·75 g/day). The primary efficacy endpoint was change from baseline to week 36 in urine protein-creatinine ratio based on a 24-h urine sample, assessed using mixed model repeated measures. Treatment-emergent adverse events (TEAEs) were safety endpoints. All endpoints were examined in all participants who received at least one dose of randomised treatment. The study is ongoing and is registered with ClinicalTrials.gov, NCT03762850. Findings: Between Dec 20, 2018, and May 26, 2021, 404 participants were randomly assigned to sparsentan (n=202) or irbesartan (n=202) and received treatment. At week 36, the geometric least squares mean percent change from baseline in urine protein-creatinine ratio was statistically significantly greater in the sparsentan group (-49·8%) than the irbesartan group (-15·1%), resulting in a between-group relative reduction of 41% (least squares mean ratio=0·59; 95% CI 0·51-0·69; p<0·0001). TEAEs with sparsentan were similar to irbesartan. There were no cases of severe oedema, heart failure, hepatotoxicity, or oedema-related discontinuations. Bodyweight changes from baseline were not different between the sparsentan and irbesartan groups. Interpretation: Once-daily treatment with sparsentan produced meaningful reduction in proteinuria compared with irbesartan in adults with IgA nephropathy. Safety of sparsentan was similar to irbesartan. Future analyses after completion of the 2-year double-blind period will show whether these beneficial effects translate into a long-term nephroprotective potential of sparsentan. Funding: Travere Therapeutics