metabolic rate
A Shank Angle-Based Control System Enables Soft Exoskeleton to Assist Human Non-Steady Locomotion
Tan, Xiaowei, Jiang, Weizhong, Zhang, Bi, Chen, Wanxin, Zhao, Yiwen, Li, Ning, Liu, Lianqing, Zhao, Xingang
Exoskeletons have been shown to effectively assist humans during steady locomotion. However, their effects on non-steady locomotion, characterized by nonlinear phase progression within a gait cycle, remain insufficiently explored, particularly across diverse activities. This work presents a shank angle-based control system that enables the exoskeleton to maintain real-time coordination with human gait, even under phase perturbations, while dynamically shaping assistance profiles to match the biological ankle moment patterns across walking, running, stair negotiation tasks. The control system consists of an assistance profile online generation method and a model-based feedforward control method. The assistance profile is formulated as a dual-Gaussian model with the shank angle as the independent variable. Leveraging only IMU measurements, the model parameters are updated online each stride to adapt to inter- and intra-individual biomechanical variability. The profile tracking control employs a human-exoskeleton kinematics and stiffness model as a feedforward component, reducing reliance on historical control data due to the lack of clear and consistent periodicity in non-steady locomotion. Three experiments were conducted using a lightweight soft exoskeleton with multiple subjects. The results validated the effectiveness of each individual method, demonstrated the robustness of the control system against gait perturbations across various activities, and revealed positive biomechanical and physiological responses of human users to the exoskeleton's mechanical assistance.
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Accelerometry-based Energy Expenditure Estimation During Activities of Daily Living: A Comparison Among Different Accelerometer Compositions
Que, Shuhao, Poelarends, Remco, Veltink, Peter, Vollenbroek-Hutten, Miriam, Wang, Ying
Physical activity energy expenditure (PAEE) can be measured from breath-by-breath respiratory data, which can serve as a reference. Alternatively, PAEE can be predicted from the body movements, which can be measured and estimated with accelerometers. The body center of mass (COM) acceleration reflects the movements of the whole body and thus serves as a good predictor for PAEE. However, the wrist has also become a popular location due to recent advancements in wrist-worn devices. Therefore, in this work, using the respiratory data measured by COSMED K5 as the reference, we evaluated and compared the performances of COM-based settings and wrist-based settings. The COM-based settings include two different accelerometer compositions, using only the pelvis accelerometer (pelvis-acc) and the pelvis accelerometer with two accelerometers from two thighs (3-acc). The wrist-based settings include using only the left wrist accelerometer (l-wrist-acc) and only the right wrist accelerometer (r-wrist-acc). We implemented two existing PAEE estimation methods on our collected dataset, where 9 participants performed activities of daily living while wearing 5 accelerometers (i.e., pelvis, two thighs, and two wrists). These two methods include a linear regression (LR) model and a CNN-LSTM model. Both models yielded the best results with the COM-based 3-acc setting (LR: $R^2$ = 0.41, CNN-LSTM: $R^2$ = 0.53). No significant difference was found between the 3-acc and pelvis-acc settings (p-value = 0.278). For both models, neither the l-wrist-acc nor the r-wrist-acc settings demonstrated predictive power on PAEE with $R^2$ values close to 0, significantly outperformed by the two COM-based settings (p-values $<$ 0.05). No significant difference was found between the two wrists (p-value = 0.329).
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Scientists develop an exoskeleton to help amputees walk with much less effort
An exoskeleton that lets amputees feel like they are'walking with two normal legs' has been developed by scientists using battery-powered electric motors. The powerful exoskeleton, which wraps around the wearer's waist and leg, was developed by a team of engineers at the University of Utah in Salt Lake City. It has been designed for above-the-knee amputees and uses battery-powered electric motors and embedded microprocessors to reduce walking effort. The 5.4lb frame is made of carbon-fibre material, plastic composites and aluminium and can walk for miles between charges, according to its creators. Those wearing it saw a 15.6 per cent reduction in their metabolic rate, equivalent to taking off a 26-pound backpack while out on a long walk, the team said.
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Good news for lazy joggers: Scientists develop ankle 'exoskeleton' that makes running easier
Couch potatoes trying to get in shape could one day be helped along their fitness journey by an ankle exoskeleton that makes it easier and less tiring to run. The robotic device attaches to the ankle of joggers and was found in lab tests to slash energy expenditure by 14 per cent when compared to standard running shoes. It was created by robotics experts at Stanford University and funded in part by sporting behemoth Nike. The engineers behind the project say the equipment currently only works on a treadmill and when the device is hooked up to a machine via cables. However, they are working to make the exoskeleton portable and lightweight and easy to integrate into future running equipment.
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EXTINCTION beaten by being lazy and lowered metabolic rates
If you're always being criticised for being lazy, it seems you could have a good excuse. A study suggests idleness is an excellent survival strategy – and the sloths among us may represent the next stage in human evolution. Scientists believe they have uncovered a previously overlooked law of natural selection based on'survival of the slacker'. This suggests that laziness can be a good strategy for ensuring the survival of individuals, species and even whole groups of species. Although the research was based on lowly molluscs living on the floor of the Atlantic, the authors believe they may have stumbled on a general principle that could apply to higher animals – including land-dwelling vertebrates.
Can a Living Creature Be as Big as a Galaxy? - Issue 51: Limits
The size of things in our universe runs all the way from the tiny 10-19 meter scale that characterizes quark interactions, to the cosmic horizon 1026 meters away. In these 45 possible orders of magnitude, life, as far as we know it, is confined to a relatively tiny bracket of just over nine orders of magnitude, roughly in the middle of the universal range: Bacteria and viruses can measure less than a micron, or 10-6 meters, and the height of the largest trees reaches roughly 100 meters. The honey fungus that lives under the Blue Mountains in Oregon, and is arguably a single living organism, is about 4 kilometers across. When it comes to known sentient life, the range in scale is even smaller, at about three orders of magnitude. Could things be any different?
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Is Interstellar Space Travel Possible? Hibernation Space Pods To Induce Stasis Being Researched By SpaceWorks
A U.S.-based company called SpaceWorks that develops technologies for space exploration is venturing into uncharted territory for scientists. It is attempting to develop hibernation pods or human stasis pods that could enable humans to partake in interstellar space missions. Such types of hibernation pods have long been a part of popular imagination through cinematic experiences in countless films and anime such as "Interstellar," "Passengers," "Prometheus" and others. However, the company based out of Atlanta, Georgia, is working to turn the science fiction into reality by researching in areas like therapeutic hypothermia, nutrition and intravenous support and metabolic rate, to realize the potential of deep space travel. The company aims to begin testing on animals in 2018, before proceeding to human subjects.
Yes, Life in the Fast Lane Kills You - Issue 36: Aging
Nick Lane is an evolutionary biochemist at University College London who thinks about the big questions of life: how it began, how it is maintained, why we age and die, and why we have sex. Shunning the habit of our times to regard these as questions for evolutionary genetics, Lane insists that our fundamental biochemical mechanisms--particularly those through which living cells generate energy--may determine or limit these facts of life. Lane has been steadily constructing an alternative, complementary view of evolution to the one in which genes compete for reproductive success and survival. He has argued that some of the big shifts during evolutionary history, such as the appearance of complex cells called eukaryotes (like our own) and the emergence of multicellular life forms, are best understood by considering the energetic constraints. Lane's book Life Ascending: The Ten Great Inventions of Evolution was awarded the 2010 Royal Society Science Books Prize, the top prize in the United Kingdom for books on science. His 2015 book The Vital Question: Why Is Life the Way It Is? has been described as "game-changing" and "brimming with bold and important ideas." It offers a new, detailed model for how life might have begun by harnessing the incipient chemical energy at deep-sea vents. Bill Gates called The Vital Question "an amazing inquiry into the origins of life."
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Can a Living Creature Be as Big as a Galaxy? - Issue 34: Adaptation
The size of things in our universe runs all the way from the tiny 10-19 meter scale that characterizes quark interactions, to the cosmic horizon 1026 meters away. In these 45 possible orders of magnitude, life, as far as we know it, is confined to a relatively tiny bracket of just over nine orders of magnitude, roughly in the middle of the universal range: Bacteria and viruses can measure less than a micron, or 10-6 meters, and the height of the largest trees reaches roughly 100 meters. The honey fungus that lives under the Blue Mountains in Oregon, and is arguably a single living organism, is about 4 kilometers across. When it comes to known sentient life, the range in scale is even smaller, at about three orders of magnitude. Progress in the theory of computation suggests that sentience and intelligence likely require quadrillions of primitive "circuit" elements. Given that our brains are composed of neurons, which are themselves, in essence, specialized cooperative single-cell organisms, we can conclude that biological computers need to be about the physical size of our own brains in order to exhibit the capabilities that we have.
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