Energy Harvesting From Ankle: Generating Electricity by Harvesting Negative Work

2018 ◽  
Author(s):  
Mingyi Liu ◽  
Wei-Che Tai ◽  
Lei Zuo
Keyword(s):  
Energy Harvesting ◽  
Mobile Devices ◽  
Human Body ◽  
Stance Phase ◽  
Metabolic Cost ◽  
Negative Energy ◽  
Battery Life ◽  
Negative Work ◽  
Limited Life ◽  
Body Energy

Portable, wearable, and mobile devices are becoming more and more popular in the past two decades. Those devices rely on batteries heavily as power source. However, the limited life span of batteries constitutes a limitation. Human body energy harvesting has the potential to power those devices, thus replacing batteries or extending battery life. Harvesting positive muscle work from human body can be a burden, and exhausts the wearer. In this paper, we developed a biomechanical energy-harvesting device that generates electricity by harvesting negative work during human walking. The energy harvester mounts on the ankle and selectively engages to generate power between the middle stance phase and terminal stance phase, during which the calf muscles do negative work. The device harvests negative energy by assisting muscles in performing negative work. Test subjects walking with the device produced an average of 0.94 watts of electric power. From treadmill test, the device was shown to harvest energy only during the negative work phase, as a result it has the potential to not to increase the metabolic cost. Producing substantial electricity without burden on the wearer makes this harvester well suited for powering wearable, portable, and mobile devices.

Develop a Flexible Regenerative Exoskeleton to Assist Walking

2018 ◽  
Author(s):  
Longhan Xie ◽  
Xiaodong Li
Keyword(s):  
Kinetic Energy ◽  
Human Body ◽  
Lower Limb ◽  
Metabolic Cost ◽  
Lower Limbs ◽  
Metabolic Energy ◽  
Lower Limb Exoskeleton ◽  
Negative Work ◽  
Lower Limb Muscles ◽  
Assisting Device

During walking, human lower limbs accelerate and decelerate alternately, during which period the human body does positive and negative work, respectively. Muscles provide power to all motions and cost metabolic energy both in accelerating and decelerating the lower limbs. In this work, the lower-limb biomechanics of walking was analyzed and it revealed that if the negative work performed during deceleration can be harnessed using some assisting device to then assist the acceleration movement of the lower limb, the total metabolic cost of the human body during walking can be reduced. A flexible lower-limb exoskeleton was then proposed; it is worn in parallel to the lower limbs to assist human walking without consuming external power. The flexible exoskeleton consists of elastic and damping components that are similar to physiological structure of a human lower limb. When worn on the lower limb, the exoskeleton can partly replace the function of the lower limb muscles and scavenge kinetic energy during lower limb deceleration to assist the acceleration movement. Besides, the generator in the exoskeleton, serving as a damping component, can harvest kinetic energy to produce electricity. A prototype of the flexible exoskeleton was developed, and experiments were carried out to validate the analysis. The experiments showed that the exoskeleton could reduce the metabolic cost by 3.12% at the walking speed of 4.5 km/h.

Fiber‐Based Energy Conversion Devices for Human‐Body Energy Harvesting

2019 ◽  
Vol 32 (5) ◽  
pp. 1902034 ◽  
Author(s):  
Liang Huang ◽  
Shizhe Lin ◽  
Zisheng Xu ◽  
He Zhou ◽  
Jiangjiang Duan ◽  
...  
Keyword(s):  
Energy Harvesting ◽  
Energy Conversion ◽  
Human Body ◽  
Body Energy ◽  
Energy Conversion Devices

Nanogenerators for Human Body Energy Harvesting

2017 ◽  
Vol 35 (7) ◽  
pp. 610-624 ◽  
Author(s):  
Antonino Proto ◽  
Marek Penhaker ◽  
Silvia Conforto ◽  
Maurizio Schmid
Keyword(s):  
Energy Harvesting ◽  
Human Body ◽  
Body Energy

scholarly journals Optimization a structure of MEMS based PDMS ferroelectret for human body energy harvesting and sensing

2019 ◽  
Vol 28 (7) ◽  
pp. 075010 ◽  
Author(s):  
Junjie Shi ◽  
Zhenhua Luo ◽  
Zhu Dibin ◽  
Steve Beeby
Keyword(s):  
Energy Harvesting ◽  
Human Body ◽  
Body Energy

scholarly journals An easy to assemble ferroelectret for human body energy harvesting

2018 ◽  
Vol 27 (8) ◽  
pp. 084005 ◽  
Author(s):  
Junjie Shi ◽  
Sheng Yong ◽  
Steve Beeby
Keyword(s):  
Energy Harvesting ◽  
Human Body ◽  
Body Energy

Design and Experimental Evaluation of Wearable Lower Extremity Exoskeleton with Gait Self-adaptivity

Robotica ◽  
2019 ◽  
Vol 37 (12) ◽  
pp. 2035-2055 ◽  
Author(s):  
Wenkang Wang ◽  
Liancun Zhang ◽  
Kangjian Cai ◽  
Zhiheng Wang ◽  
Bainan Zhang ◽  
...  
Keyword(s):  
Lower Extremity ◽  
Human Body ◽  
Stance Phase ◽  
Detection System ◽  
Metabolic Cost ◽  
Knee Joints ◽  
Human Gait ◽  
External Energy ◽  
Pulling Forces ◽  
External Energy Source

SummaryIn this paper, we present a passive lower extremity exoskeleton with a simple structure and a light weight. The exoskeleton does not require any external energy source and can achieve energy transfer only by human body’s own gravity. The exoskeleton is self-adaptive to human gait to achieve basic matching therewith. During walking, pulling forces are generated through Bowden cables by pressing plantar power output devices by feet, and the forces are transmitted to the exoskeleton through a crank-slider mechanism to enable the exoskeleton to provide torques for the ankle and knee joints as required by the human body during the stance phase and the swing phase. Our self-developed gait detection system is used to perform experiments on kinematics, dynamics and metabolic cost during walking of the human body wearing the exoskeleton in different states. The experimental results show that the exoskeleton has the greatest influence on motion of the ankle joint and has the least influence on hip joint. With the increase in elastic coefficient of the spring, the torques generated at the joints by the exoskeleton increase. When walking with wearing k3EF exoskeleton at a speed of 0.5 m/s, it can save the most metabolic cost, reaching 13.63%.

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