We developed an autonomous powered leg exoskeleton capable of providing large amounts of positive mechanical power to the wearer during powered plantarflexion phase of walking. The autonomous exoskeleton consisted of a winch actuator fasted to the shin which pulled on fiberglass struts attached to a boot. The fiberglass struts formed a rigid extension of the foot when the proximal end of the strut was pulled in forward by the winch actuator. This lightweight, geometric transmission allowed the electric winch actuator to efficiently produce biological levels of power at the ankle joint. The exoskeleton was powered and controlled by lithium polymer batteries and motor controller worn around the waist. Preliminary testing on two subjects walking at 1.4 m/s resulted in the exoskeleton reducing the metabolic cost of walking by 6-11% as compared to not wearing the device. The exoskeleton provided a peak mechanical power of over 180 W at each ankle (mean standard ± deviation) and an average positive mechanical power of 27 ± 1 W total to both ankles, while electrically using 75-89 W of electricity. The batteries (800 g) used in this experiment are estimated to be capable of providing this level of assistance for up to 7 km of walking.
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http://dx.doi.org/10.1109/EMBC.2014.6944270 | DOI Listing |
Environ Sci Pollut Res Int
December 2024
Biosystem Engineering Department, Tarbiat Modares University (TMU), Tehran, Iran.
Today, there are environmental problems all over the world due to the emission of greenhouse gasses caused by the combustion of diesel fuel. The excessive consumption and drastic reduction of fossil fuels have prompted the leaders of various countries, including Iran, to put the use of alternative and clean energy sources on the agenda. In recent years, the use of biofuels and the addition of nanoparticles to diesel fuel have reduced pollutant emissions, improved the environment, and enhanced the physicochemical properties of the fuel.
View Article and Find Full Text PDFJ Neuroeng Rehabil
December 2024
Chair of Autonomous Systems and Mechatronics, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany.
Wearable robots are often powered by elastic actuators, which can mimic the intrinsic compliance observed in human joints, contributing to safe and seamless interaction. However, due to their increased complexity, when compared to direct drives, elastic actuators are susceptible to faults, which pose significant challenges, potentially compromising user experience and safety during interaction. In this article, we developed a fault-tolerant control strategy for torque assistance in a knee exoskeleton and investigated user experience during a walking task while emulating faults.
View Article and Find Full Text PDFSci Rep
December 2024
School of Oil & Natural Gas Engineering, SouthWest Petroleum University, Chengdu, 610500, China.
Unconventional gas reservoirs, characterized by their complex geologies and challenging extraction conditions, demand innovative approaches to enhance gas production and ensure economic viability. Well stimulation techniques, such as hydraulic fracturing and acidizing, have become indispensable tools in unlocking the potential of these tight formations. However, the effectiveness of these techniques can vary widely depending on the specific characteristics of the reservoir.
View Article and Find Full Text PDFSci Rep
December 2024
Civil and Environmental Engineering Department, King Fahd University of Petroleum & Minerals, Dhahran, 31261, Saudi Arabia.
Air pollution monitoring and modeling are the most important focus of climate and environment decision-making organizations. The development of new methods for air quality prediction is one of the best strategies for understanding weather contamination. In this research, different air quality parameters were forecasted, including Carbon Monoxide (CO), Nitrogen Monoxide (NO), Nitrogen Dioxide (NO), Ozone (O), Sulphur Dioxide (SO), Fine Particles Matter (PM), Coarse Particles Matter (PM), and Ammonia (NH).
View Article and Find Full Text PDFSci Rep
December 2024
The Ministry of Education Key Laboratory of High Efficiency Mining and Safety for Metal Mines & School of Civil and Resources Engineering, University of Science and Technology Beijing, Beijing, 100083, People's Republic of China.
Coarse particles in filling slurry are the primary factor causing wear in filling elbow pipes, and the wear mechanism of these particles on the pipes is influenced by various factors. To study the erosion and wear mechanism of elbow pipes caused by coarse particles, the motion state of coarse particles under different curvature radii, coarse particle gradations, and pipe diameters was investigated using a simulation method based on the coupling of Fluent and EDEM software, grounded in theories of fluid mechanics, rheology, and solid-liquid two-phase flow. The study explored the impact patterns and locations of wear induced by coarse particles on filling elbow pipes.
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