A Compact, Modular Series Elastic Actuator

2016 ◽  
Vol 8 (4) ◽  
Author(s):  
Jonathan P. Cummings ◽  
Dirk Ruiken ◽  
Eric L. Wilkinson ◽  
Michael W. Lanighan ◽  
Roderic A. Grupen ◽  
...  
Keyword(s):  
High Performance ◽  
Negative Impact ◽  
Peak Torque ◽  
Mobile Manipulator ◽  
Brushless Motors ◽  
Hall Effect Sensor ◽  
Series Elastic Actuator ◽  
Wide Range ◽  
Active Impedance ◽  
Series Elastic

This paper presents the development of a compact, modular rotary series elastic actuator (SEA) design that can be customized to meet the requirements of a wide range of applications. The concept incorporates flat brushless motors and planetary gearheads instead of expensive harmonic drives and a flat torsional spring design to create a lightweight, low-volume, easily reconfigurable, and relatively high-performance modular SEA for use in active impedance controlled devices. The key innovations include a Hall effect sensor for direct spring displacement measurements that mitigate the negative impact of backlash on SEA control performance. Both torque and impedance controllers are developed and evaluated using a 1-degree-of-freedom (DoF) prototype of the proposed actuator package. The results demonstrate the performance of a stable first-order impedance controller tested over a range of target impedances. Finally, the flexibility of the modular SEA is demonstrated by configuring it for use in five different actuator specifications designed for use in the uBot-7 mobile manipulator requiring spring stiffnesses from 3 N · m/deg to 11.25 N · m/deg and peak torque outputs from 12 N · m to 45 N · m.

scholarly journals Design and Preliminary Results of a Reaction Force Series Elastic Actuator for Bionic Ankle Prostheses

2019 ◽  
Author(s):  
Matt Carney ◽  
Tony Shu ◽  
Roman Stolyarov ◽  
Jean-Francois Duval ◽  
Hugh Herr
Keyword(s):  
Energy Storage ◽  
Mechanical Design ◽  
Mechanical Energy ◽  
Reaction Force ◽  
Electrical Energy ◽  
Peak Torque ◽  
Walking Gait ◽  
Series Elastic Actuator ◽  
Hardware Specification ◽  
Series Elastic

The TF8 actuator is an untethered, lower-extremity powered-prostheses designed to replicate biological kinetic and kinematic function of ankles. An energy optimal hardware specification was found by kinematically clamping walking gait data to the dynamic model of a series elastic actuator (SEA). We searched for a minimal electrical energy configuration of motor, reduction ratio, and spring, subject to specified constraints and ultimately discretely available components. The outcome translated into a mechanical design that heavily weighted the importance of mechanical energy storage in springs. The resulting design is a moment-coupled cantilever-beam reaction-force SEA (RFSEA) that has a nominal torque rating of 85Nm, peak torque of 175Nm, 105 degree range of motion, and a hardware mass of 1.6kg.

scholarly journals Artificial Knee Joints Actuators with Energy Recovery Capabilities: A Comparison of Performance

2016 ◽  
Vol 2016 ◽  
pp. 1-13 ◽  
Author(s):  
Roberta Alò ◽  
Francesco Bottiglione ◽  
Giacomo Mantriota
Keyword(s):  
Electric Motor ◽  
Energy Recovery ◽  
Peak Torque ◽  
Lower Limbs ◽  
Wearable Robot ◽  
Series Elastic Actuator ◽  
Actuation System ◽  
Performance Indexes ◽  
Variable Transmission ◽  
Series Elastic

The human knee absorbs more energy than it expends in level ground walking. For this reason it would be useful if the actuation system of a wearable robot for lower limbs was able to recover energy thus improving portability. Presently, we recognize three promising technologies with energy recovery capabilities already available in the literature: the Series Elastic Actuator (SEA), the Clutchable Series Elastic Actuator (C-SEA), and the flywheel Infinitely Variable Transmission (F-IVT) actuator. In this paper, a simulation model based comparison of the performance of these actuators is presented. The focus is on two performance indexes: the energy consumed by the electric motor per gait and the peak torque/power requested to the electric motor. Both quantities are related to the portability of the device: the former affects the size of the batteries for a given desired range; the latter affects the size and the weight of the electric motor. The results show that, besides some well-explained limitations of the presented methodology, the C-SEA is the most energy efficient whereas the F-IVT allows cutting down the motor torque/peak power strongly. The analysis also leads to defining how it is possible to improve the F-IVT to achieve a reduction of the energy consumption.

Validated Stability Indicating HPTLC Method for the Estimation of Amoxapine in Different Stress Conditions

2019 ◽  
Vol 15 (3) ◽  
pp. 273-279
Author(s):  
Shweta G. Rangari ◽  
Nishikant A. Raut ◽  
Pradip W. Dhore
Keyword(s):  
High Performance ◽  
Limit Of Detection ◽  
Degradation Products ◽  
Analysis Data ◽  
Peak Height ◽  
Good Resolution ◽  
Stability Indicating ◽  
Limit Of Quantitation ◽  
Wide Range ◽  
Hptlc Method

Background:The unstable and/or toxic degradation products may form due to degradation of drug which results into loss of therapeutic activity and lead to life threatening condition. Hence, it is important to establish the stability characteristics of drug in various conditions such as in temperature, light, oxidising agent and susceptibility across a wide range of pH values.Introduction:The aim of the proposed study was to develop simple, sensitive and economic stability indicating high performance thin layer chromatography (HPTLC) method for the quantification of Amoxapine in the presence of degradation products.Methods:Amoxapine and its degraded products were separated on precoated silica gel 60F254 TLC plates by using mobile phase comprising of methanol: toluene: ammonium acetate (6:3:1, v/v/v). The densitometric evaluation was carried out at 320 nm in reflectance/absorbance mode. The degradation products obtained as per ICH guidelines under acidic, basic and oxidative conditions have different Rf values 0.12, 0.26 and 0.6 indicating good resolution from each other and pure drug with Rf: 0.47. Amoxapine was found to be stable under neutral, thermal and photo conditions.Results:The method was validated as per ICH Q2 (R1) guidelines in terms of accuracy, precision, ruggedness, robustness and linearity. A good linear relationship between concentration and response (peak area and peak height) over the range of 80 ng/spot to 720 ng/spot was observed from regression analysis data showing correlation coefficient 0.991 and 0.994 for area and height, respectively. The limit of detection (LOD) and limit of quantitation (LOQ) for area were found to be 1.176 ng/mL and 3.565 ng/mL, whereas for height, 50.063 ng/mL and 151.707 ng/mL respectively.Conclusion:The statistical analysis confirmed the accuracy, precision and selectivity of the proposed method which can be effectively used for the analysis of amoxapine in the presence of degradation products.

Phytochemical, Analytical and Medicinal Studies of Holoptelea integrifolia Roxb. Planch - A Review

2019 ◽  
Vol 5 (4) ◽  
pp. 270-277 ◽  
Author(s):  
Vijay Kumar ◽  
Simranjeet Singh ◽  
Ragini Bhadouria ◽  
Ravindra Singh ◽  
Om Prakash
Keyword(s):  
Liquid Chromatography ◽  
Thin Layer ◽  
Thin Layer Chromatography ◽  
High Performance ◽  
Biologically Active ◽  
Toxicological Studies ◽  
Wide Range ◽  
Layer Chromatography

Holoptelea integrifolia Roxb. Planch (HI) has been used to treat various ailments including obesity, osteoarthritis, arthritis, inflammation, anemia, diabetes etc. To review the major phytochemicals and medicinal properties of HI, exhaustive bibliographic research was designed by means of various scientific search engines and databases. Only 12 phytochemicals have been reported including biologically active compounds like betulin, betulinic acid, epifriedlin, octacosanol, Friedlin, Holoptelin-A and Holoptelin-B. Analytical methods including the Thin Layer Chromatography (TLC), High-Performance Thin Layer Chromatography (HPTLC), High-Performance Liquid Chromatography (HPLC) and Liquid Chromatography With Mass Spectral (LC-MS) analysis have been used to analyze the HI. From medicinal potency point of view, these phytochemicals have a wide range of pharmacological activities such as antioxidant, antibacterial, anti-inflammatory, and anti-tumor. In the current review, it has been noticed that the mechanism of action of HI with biomolecules has not been fully explored. Pharmacology and toxicological studies are very few. This seems a huge literature gap to be fulfilled through the detailed in-vivo and in-vitro studies.

scholarly journals RELaTED Project: New Developments on Ultra-Low Temperature District Heating Networks

Proceedings ◽  
2020 ◽  
Vol 65 (1) ◽  
pp. 25
Author(s):  
Antonio Garrido Marijuan ◽  
Roberto Garay ◽  
Mikel Lumbreras ◽  
Víctor Sánchez ◽  
Olga Macias ◽  
...  
Keyword(s):  
Low Temperature ◽  
High Performance ◽  
Waste Heat ◽  
District Heating ◽  
Hot Water ◽  
Thermal Systems ◽  
Heating Source ◽  
Wide Range ◽  
Thermal Sources ◽  
Heating Networks

District heating networks deliver around 13% of the heating energy in the EU, being considered as a key element of the progressive decarbonization of Europe. The H2020 REnewable Low TEmperature District project (RELaTED) seeks to contribute to the energy decarbonization of these infrastructures through the development and demonstration of the following concepts: reduction in network temperature down to 50 °C, integration of renewable energies and waste heat sources with a novel substation concept, and improvement on building-integrated solar thermal systems. The coupling of renewable thermal sources with ultra-low temperature district heating (DH) allows for a bidirectional energy flow, using the DH as both thermal storage in periods of production surplus and a back-up heating source during consumption peaks. The ultra-low temperature enables the integration of a wide range of energy sources such as waste heat from industry. Furthermore, RELaTED also develops concepts concerning district heating-connected reversible heat pump systems that allow to reach adequate thermal levels for domestic hot water as well as the use of the network for district cooling with high performance. These developments will be demonstrated in four locations: Estonia, Serbia, Denmark, and Spain.

scholarly journals Treatment patterns and appropriateness of antipsychotic prescriptions in patients with schizophrenia

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Verónica Gamón ◽  
Isabel Hurtado ◽  
José Salazar-Fraile ◽  
Gabriel Sanfélix-Gimeno
Keyword(s):  
Negative Impact ◽  
Current Treatment ◽  
Treatment Patterns ◽  
Mental Condition ◽  
Comorbid Condition ◽  
Concomitant Treatment ◽  
Antipsychotic Medications ◽  
Wide Range ◽  
Schizophrenic Patients ◽  
High Level

AbstractSchizophrenia is a chronic mental condition presenting a wide range of symptoms. Although it has a low prevalence compared to other mental conditions, it has a negative impact on social and occupational functions. This study aimed to assess the appropriateness of antipsychotic medications administered to schizophrenic patients and describe current treatment patterns for schizophrenia. A retrospective cohort study was conducted in all patients over the age of 15 with an active diagnosis of schizophrenia and treated with antipsychotics between 2008 and 2013 in the Valencia region. A total of 19,718 patients were eligible for inclusion. The main outcome assessed was inappropriateness of the pharmacotherapeutic management, including polypharmacy use. Altogether, 30.4% of patients received antipsychotic polypharmacy, and 6.8% were prescribed three or more antipsychotics. Overdosage affected 318 individuals (1.6%), and 21.5% used concomitant psychotropics without an associated psychiatric diagnosis. Women and people with a comorbid condition like anxiety or depression were less likely to receive antipsychotic polypharmacy. In contrast, increased polypharmacy was associated with concomitant treatment with other psychoactive drugs, and only in user on maintenance therapy, with more visits to the mental health hospital. Overall, we observed a high level of inappropriateness in antipsychotic prescriptions. Greater adherence to guidelines could maximize the benefits of antipsychotic medications while minimizing risk of adverse effects.

scholarly journals Applicability of Cork as Novel Modifiers to Develop Electrochemical Sensor for Caffeine Determination

Materials ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 37
Author(s):  
Mayra K. S. Monteiro ◽  
Djalma R. Da Silva ◽  
Marco A. Quiroz ◽  
Vítor J. P. Vilar ◽  
Carlos A. Martínez-Huitle ◽  
...  
Keyword(s):  
Electrochemical Sensor ◽  
Linear Response ◽  
High Performance ◽  
Low Cost ◽  
Pharmaceutical Formulations ◽  
Caffeine Concentration ◽  
Real Samples ◽  
Wide Range ◽  
Potential Use

This study aims to investigate the applicability of a hybrid electrochemical sensor composed of cork and graphite (Gr) for detecting caffeine in aqueous solutions. Raw cork (RAC) and regranulated cork (RGC, obtained by thermal treatment of RAC with steam at 380 °C) were tested as modifiers. The results clearly showed that the cork-graphite sensors, GrRAC and GrRGC, exhibited a linear response over a wide range of caffeine concentration (5–1000 µM), with R2 of 0.99 and 0.98, respectively. The limits of detection (LOD), estimated at 2.9 and 6.1 µM for GrRAC and GrRGC, suggest greater sensitivity and reproducibility than the unmodified conventional graphite sensor. The low-cost cork-graphite sensors were successfully applied in the determination of caffeine in soft drinks and pharmaceutical formulations, presenting well-defined current signals when analyzing real samples. When comparing electrochemical determinations and high performance liquid chromatography measurements, no significant differences were observed (mean accuracy 3.0%), highlighting the potential use of these sensors to determine caffeine in different samples.

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