Reducing the metabolic rate of walking and running with a versatile, portable exosuit

Kim, Jin-Soo; Lee, Giuk; Heimgartner, Roman; Revi, Dheepak Arumukhom; Karavas, Nikos; Nathanson, Danielle; Galiana, Ignacio; Eckert-Erdheim, Asa; Murphy, Patrick J.; Perry, David; Menard, Nicolas; Choe, Dabin K.; Malcolm, Philippe; Walsh, Conor J.

doi:10.1126/science.aav7536

Cited by 331 publications

(280 citation statements)

References 80 publications

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“…There are "super subjects" in other studies [4,19], although the variance in other studies is not as large as that in this study. In a sense, The reaction force of the interaction force is borne by the calf, so the peak interaction is limited by the pressure that the calf can withstand.…”

Section: Start Endcontrasting

confidence: 68%

“…In terms of the amount of the net reduction in metabolic cost, our robot achieved a result similar to those of some of the best research at present. The average net metabolic cost reduction of 8.7±8.1% in power-on walking compared to free walking was slightly more than the 7.3±5.0% in study [33] and slightly less than the 11±4% in study [4] and the 9.3% in the study that designed a hip robot [19].…”

Section: Start Endmentioning

confidence: 75%

“…Although the robot achieved 11±4% net metabolic cost reduction with the assisting power of 0.105± 0.008 W/kg per leg, the weight of the actuators (approximately 1.1kg/leg) borne by the shank led to a metabolic cost higher than that borne by the back [17]. Ye Ding and his colleagues designed a robot to assist hip extension, which achieved a reduction in net metabolic cost of 8.5±0.9% in 2016 [18] and achieved a 9.3 ± 2.2% reduction in net metabolic cost in another study in 2019 [19]. However, simply reducing the weight of the motor and reducer causes the robots to fail to meet the power requirements because the weight of the motor and the reducer is related to the specific power.…”

Section: Introductionmentioning

confidence: 99%

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Improving the Assisting Efficiency of Ankle Robot through Energy Harvesting of Achilles Tendon

Huang

Wang

Liu

et al. 2020

Preprint

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Background The construction of lightweight robots poses one of the major challenges in the field of active robots since bearing the weight of an active robot significantly increases metabolic cost. However, few studies have achieved a substantial reduction in the robot weight. The primary reason is that the weight of the actuator, which comprises the main weight of the robot, is limited by the specific power, power requirements and assisting efficiency. Methods In this paper, we propose a new method that is utilizing the energy harvesting function of the Achilles tendon to improve the assistance efficiency of ankle robots to reduce the weight of the actuator and we design a novel ankle robot to test the validity of the method. The robot works with the ankle plantar flexor at 43%-60% of the gait cycle and has no other effects on the joints or the tendon of the lower limb. Healthy subjects were recruited to test the prototype in three conditions: free walking, power-on walking, and power-off walking. Data on the robot assisting power, metabolic cost and kinematics in different conditions were collected and analyzed. Result The results showed that the ankle robot can deliver forces at the controlled assistance timing. The average assisting power of 0.0650±0.0054 W/kg per leg resulted in an 8.7±8.1% and 19.0±6.4% net reduction in metabolic cost in power-on walking compared to free-walking and power-off walking, respectively. Conclusion Compared with the results of some of the best research, our initial result supports the validity of the method. This method can help to reduce the weight of active robots and the technical innovative method to determine the assistance timing more accurately and the novel design of the ankle robot can provide a reference for future research. To the best of our knowledge, this method is the first to use the human physiological structure to optimize the design of active robots.

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Section: Start Endcontrasting

confidence: 68%

Section: Start Endmentioning

confidence: 75%

Section: Introductionmentioning

confidence: 99%

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Improving the Assisting Efficiency of Ankle Robot through Energy Harvesting of Achilles Tendon

Huang

Wang

Liu

et al. 2020

Preprint

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“…[218] In a recent study, Kim et al demonstrated a similar soft exosuit that promised to reduce metabolic rates while a person is subjected to motion vis-à-vis running. [219] Robots are increasingly envisaged to enter into tasks that involve contact with humans. To make a safer human-machine interaction, it is needed to redesign robots that mimic soft natural organisms (Figure 14c).…”

Section: Soft Robotics and Neuromechanicsmentioning

confidence: 99%

Wearable and Stretchable Strain Sensors: Materials, Sensing Mechanisms, and Applications

Souri¹,

Banerjee

Jusufi

et al. 2020

Advanced Intelligent Systems

366

289

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Recent advances in the design and implementation of wearable resistive, capacitive, and optical strain sensors are summarized herein. Wearable and stretchable strain sensors have received extensive research interest due to their applications in personalized healthcare, human motion detection, human–machine interfaces, soft robotics, and beyond. The disconnection of overlapped nanomaterials, reversible opening/closing of microcracks in sensing films, and alteration of the tunneling resistance have been successfully adopted to develop high‐performance resistive‐type sensors. On the other hand, the sensing behavior of capacitive‐type and optical strain sensors is largely governed by their geometrical changes under stretching/releasing cycles. The sensor design parameters, including stretchability, sensitivity, linearity, hysteresis, and dynamic durability, are comprehensively discussed. Finally, the promising applications of wearable strain sensors are highlighted in detail. Although considerable progress has been made so far, wearable strain sensors are still in their prototype stage, and several challenges in the manufacturing of integrated and multifunctional strain sensors should be yet tackled.

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“…Exoskeletons are a class of wearable devices that often act in parallel with human MTs to restore or augment human movement. An increasing number of studies 13 are establishing that both tethered 14-18 and portable 19-21 lower-limb exoskeletons can deliver mechanical power to the body to reduce metabolic demand during walking in young healthy individuals 14-22 , individuals post-stroke 23 , and older adults 24,25 . Recently, our group has demonstrated that exoskeletons need not deliver net external mechanical power to the body to reduce the metabolic rate of walking 26 .…”

Section: Introductionmentioning

confidence: 99%

Ultrasound imaging links soleus muscle neuromechanics and energetics during human walking with elastic ankle exoskeletons

Nuckols

Dick

Beck

et al. 2020

Preprint

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26Unpowered exoskeletons with springs in parallel to human plantar flexor muscle-tendons can reduce the 27 metabolic cost of walking. We used ultrasound imaging to look 'under the skin' and measure how 28 exoskeleton stiffness alters soleus muscle contractile dynamics and shapes the user's metabolic rate 29 during walking. Eleven participants (4F, 7M; age: 27.7 ± 3.3 years) walked on a treadmill at 1.25 m s -1 30 and 0% grade with elastic ankle exoskeletons (rotational stiffness: 0-250 Nm rad -1 ) in one training and 31 two testing days. Metabolic savings were maximized (4.2%) at a stiffness of 50 Nm rad -1 . As 32 exoskeleton stiffness increased, the soleus muscle operated at longer lengths and improved economy 33 (force/activation) during early stance, but this benefit was offset by faster shortening velocity and poorer 34 economy in late stance. Changes in soleus activation rate correlated with changes in users' metabolic 35 rate (p = 0.038, R 2 = 0.44), highlighting a crucial link between muscle neuromechanics and exoskeleton 36 performance; perhaps informing future 'muscle-in-the loop' exoskeleton controllers designed to steer 37 contractile dynamics toward more economical force production. 38 39 40 41 48the plantar flexors and Achilles tendon is tuned. Throughout early stance, 0% (heel strike) to 40% 49 stride, plantar flexor muscle fascicles generate force isometrically while the Achilles tendon stretches 50 and stores mechanical energy 6 . In late stance, 40% to 60% (toe-off) stride, the plantar flexors shorten 51 and the tendon rapidly recoils, providing a burst of positive mechanical power 1,4,7 . This coordinated MT 52 interaction permits the plantar flexor muscle fascicles to operate over a narrow region of their force-53 length (F-L) curve and remain at slow shortening velocities which are favorable contractile conditions 54 for economical force production 7-12 . Any disruption to this 'catapult' like mechanism may decrease the 55 ankle's efficient mechanical power production and worsen walking efficiency. 57Exoskeletons are a class of wearable devices that often act in parallel with human MTs to restore or 58 augment human movement. An increasing number of studies 13 are establishing that both tethered 14-18 59 and portable 19-21 lower-limb exoskeletons can deliver mechanical power to the body to reduce metabolic 60 demand during walking in young healthy individuals 14-22 , individuals post-stroke 23 , and older adults 24,25 . 61 Recently, our group has demonstrated that exoskeletons need not deliver net external mechanical power 62 to the body to reduce the metabolic rate of walking 26 . We showed that elastic exoskeletons that place a 63 tension spring in parallel with the human plantar flexor-Achilles tendon complex can reduce the net 64 metabolic rate of walking by an average of 7.2% 26 versus not using a device. The relationship between 65 the user's net metabolic rate and the rotational stiffness of the exoskeleton is bowl-shaped, with a 66 'sweet-spot' that maximizes metabolic benefit...

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Reducing the metabolic rate of walking and running with a versatile, portable exosuit

Cited by 331 publications

References 80 publications

Improving the Assisting Efficiency of Ankle Robot through Energy Harvesting of Achilles Tendon

Improving the Assisting Efficiency of Ankle Robot through Energy Harvesting of Achilles Tendon

Wearable and Stretchable Strain Sensors: Materials, Sensing Mechanisms, and Applications

Ultrasound imaging links soleus muscle neuromechanics and energetics during human walking with elastic ankle exoskeletons

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