scholarly journals Design and evaluation of a hybrid passive–active knee prosthesis on energy consumption

2020 ◽  
Vol 11 (2) ◽  
pp. 425-436
Author(s):  
Xiaoming Wang ◽  
Qiaoling Meng ◽  
Zhewen Zhang ◽  
Jinyue Sun ◽  
Jie Yang ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Knee Prosthesis ◽  
Metabolic Cost ◽  
Knee Prostheses ◽  
Hydraulic Damper ◽  
Operating Modes ◽  
Gait Characteristics ◽  
Energy Consumption Model ◽  
Active Motor ◽  
Damping Torque

Abstract. The existing lower limb prostheses with passive knees have disadvantages, causing an asymmetric gait and higher metabolic cost during level walking which is in contrast with a normal gait. However, most existing active knee prostheses need a significant amount of energy. In this paper, a novel hybrid passive–active knee prosthesis (HPAK) that allows passive and active operating modes is proposed, which contains an active motor unit and a novel hydraulic damper with an electrically controlled valve that adjusts the damping torque dynamically during each gait cycle. An energy consumption model was built to evaluate the energy consumption when walking on level ground in three different simulation conditions to, respectively, simulate the complete HPAK, an ordinary active prosthesis (AKP) and an ordinary passive prosthesis (PKP). The results show that, in a cycle, the HPAK consumes only 16.19 J, which is 3.6 times lower than the AKP (58.95 J), and the PKP consumes only 1.24 J due to the novel spring–hydraulic damper structure designed and presented in this paper. These results indicate that the proposed novel hybrid passive–active knee prosthesis can have a positive effect on reducing energy consumption and improving the approximation of healthy gait characteristics when walking on level ground, contrasting with active or passive knee prostheses.

scholarly journals Design of a Passive, Shear-Based Rotary Hydraulic Damper for Single-Axis Prosthetic Knees

2018 ◽  
Author(s):  
V. N. Murthy Arelekatti ◽  
Nina T. Petelina ◽  
W. Brett Johnson ◽  
Amos G. Winter ◽  
Matthew J. Major
Keyword(s):  
High Performance ◽  
Silicone Oil ◽  
Low Cost ◽  
Knee Kinematics ◽  
High Viscosity ◽  
Knee Prostheses ◽  
Hydraulic Damper ◽  
Optimal Damping ◽  
Prosthetic Knees ◽  
Damping Torque

With over 30 million people worldwide in need of assistive devices, there is a great need for low-cost, high performance prosthetic technologies in the developing world. A majority of the hydraulic dampers used in prosthetic knee designs are highly specialized, expensive, require regular maintenance, and are incompatible for use with low-cost, single-axis prosthetic knees popular in developing countries. In this study, optimal damping coefficients were computed based on a theoretical analysis of gait, specifically during the transition from the stance to swing phase of human walking when a large damping torque is needed at the knee. A novel rotary hydraulic damper prototype was designed using high-viscosity silicone oil and a concentric meshing of fins for shearing the oil. The prototype was validated experimentally to provide the desired damping torque profile. For preliminary, user-centric validation of the prototype, a gait study on one above-knee amputee in India was conducted with four different damping magnitudes. Feedback from the subject validated the optimal damping torque magnitude predicted for minimizing gait deviations and for enabling able-bodied knee kinematics. The new rotary hydraulic damper design is novel, passive, and compatible with low-cost, single-axis knee prostheses.

scholarly journals Reducing the metabolic energy of walking and running using an unpowered hip exoskeleton

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Tiancheng Zhou ◽  
Caihua Xiong ◽  
Juanjuan Zhang ◽  
Di Hu ◽  
Wenbin Chen ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Design Method ◽  
Metabolic Cost ◽  
Metabolic Energy ◽  
Spring Stiffness ◽  
Spatiotemporal Parameters ◽  
The Common ◽  
Hip Flexion ◽  
Optimal Stiffness ◽  
Insight Into

Abstract Background Walking and running are the most common means of locomotion in human daily life. People have made advances in developing separate exoskeletons to reduce the metabolic rate of walking or running. However, the combined requirements of overcoming the fundamental biomechanical differences between the two gaits and minimizing the metabolic penalty of the exoskeleton mass make it challenging to develop an exoskeleton that can reduce the metabolic energy during both gaits. Here we show that the metabolic energy of both walking and running can be reduced by regulating the metabolic energy of hip flexion during the common energy consumption period of the two gaits using an unpowered hip exoskeleton. Methods We analyzed the metabolic rates, muscle activities and spatiotemporal parameters of 9 healthy subjects (mean ± s.t.d; 24.9 ± 3.7 years, 66.9 ± 8.7 kg, 1.76 ± 0.05 m) walking on a treadmill at a speed of 1.5 m s−1 and running at a speed of 2.5 m s−1 with different spring stiffnesses. After obtaining the optimal spring stiffness, we recruited the participants to walk and run with the assistance from a spring with optimal stiffness at different speeds to demonstrate the generality of the proposed approach. Results We found that the common optimal exoskeleton spring stiffness for walking and running was 83 Nm Rad−1, corresponding to 7.2% ± 1.2% (mean ± s.e.m, paired t-test p < 0.01) and 6.8% ± 1.0% (p < 0.01) metabolic reductions compared to walking and running without exoskeleton. The metabolic energy within the tested speed range can be reduced with the assistance except for low-speed walking (1.0 m s−1). Participants showed different changes in muscle activities with the assistance of the proposed exoskeleton. Conclusions This paper first demonstrates that the metabolic cost of walking and running can be reduced using an unpowered hip exoskeleton to regulate the metabolic energy of hip flexion. The design method based on analyzing the common energy consumption characteristics between gaits may inspire future exoskeletons that assist multiple gaits. The results of different changes in muscle activities provide new insight into human response to the same assistive principle for different gaits (walking and running).

scholarly journals Machine Learning-Based Energy System Model for Tissue Paper Machines

Processes ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 655
Author(s):  
Huanhuan Zhang ◽  
Jigeng Li ◽  
Mengna Hong
Keyword(s):  
Neural Network ◽  
Energy Consumption ◽  
Gradient Boosting ◽  
Paper Machine ◽  
Steam Consumption ◽  
Tissue Paper ◽  
Paper Machines ◽  
Energy Consumption Model ◽  
Extreme Gradient Boosting ◽  
Consumption Model

With the global energy crisis and environmental pollution intensifying, tissue papermaking enterprises urgently need to save energy. The energy consumption model is essential for the energy saving of tissue paper machines. The energy consumption of tissue paper machine is very complicated, and the workload and difficulty of using the mechanism model to establish the energy consumption model of tissue paper machine are very large. Therefore, this article aims to build an empirical energy consumption model for tissue paper machines. The energy consumption of this model includes electricity consumption and steam consumption. Since the process parameters have a great influence on the energy consumption of the tissue paper machines, this study uses three methods: linear regression, artificial neural network and extreme gradient boosting tree to establish the relationship between process parameters and power consumption, and process parameters and steam consumption. Then, the best power consumption model and the best steam consumption model are selected from the models established by linear regression, artificial neural network and the extreme gradient boosting tree. Further, they are combined into the energy consumption model of the tissue paper machine. Finally, the models established by the three methods are evaluated. The experimental results show that using the empirical model for tissue paper machine energy consumption modeling is feasible. The result also indicates that the power consumption model and steam consumption model established by the extreme gradient boosting tree are better than the models established by linear regression and artificial neural network. The experimental results show that the power consumption model and steam consumption model established by the extreme gradient boosting tree are better than the models established by linear regression and artificial neural network. The mean absolute percentage error of the electricity consumption model and the steam consumption model built by the extreme gradient boosting tree is approximately 2.72 and 1.87, respectively. The root mean square errors of these two models are about 4.74 and 0.03, respectively. The result also indicates that using the empirical model for tissue paper machine energy consumption modeling is feasible, and the extreme gradient boosting tree is an efficient method for modeling energy consumption of tissue paper machines.

scholarly journals Limitations of Foot-Worn Sensors for Assessing Running Power

Sensors ◽  
2021 ◽  
Vol 21 (15) ◽  
pp. 4952
Author(s):  
Tobias Baumgartner ◽  
Steffen Held ◽  
Stefanie Klatt ◽  
Lars Donath
Keyword(s):  
Time Use ◽  
Stride Length ◽  
Metabolic Cost ◽  
Running Economy ◽  
Accelerometer Data ◽  
Gait Characteristics ◽  
Significant Difference ◽  
Metabolic Costs ◽  
Ground Contact Time ◽  
Training Signal

Running power as measured by foot-worn sensors is considered to be associated with the metabolic cost of running. In this study, we show that running economy needs to be taken into account when deriving metabolic cost from accelerometer data. We administered an experiment in which 32 experienced participants (age = 28 ± 7 years, weekly running distance = 51 ± 24 km) ran at a constant speed with modified spatiotemporal gait characteristics (stride length, ground contact time, use of arms). We recorded both their metabolic costs of transportation, as well as running power, as measured by a Stryd sensor. Purposely varying the running style impacts the running economy and leads to significant differences in the metabolic cost of running (p < 0.01). At the same time, the expected rise in running power does not follow this change, and there is a significant difference in the relation between metabolic cost and power (p < 0.001). These results stand in contrast to the previously reported link between metabolic and mechanical running characteristics estimated by foot-worn sensors. This casts doubt on the feasibility of measuring running power in the field, as well as using it as a training signal.

Novel active magnetorheological knee prosthesis presents low energy consumption during ground walking

2021 ◽  
pp. 1045389X2098392
Author(s):  
Rafhael Milanezi de Andrade ◽  
Jordana Simões Ribeiro Martins ◽  
Marcos Pinotti ◽  
Antônio Bento Filho ◽  
Claysson Bruno Santos Vimieiro
Keyword(s):  
Energy Consumption ◽  
Stance Phase ◽  
Gait Cycle ◽  
Dynamic Models ◽  
Knee Prosthesis ◽  
Regenerative Braking ◽  
Harmonic Drive ◽  
Low Energy Consumption ◽  
Energetic Expenditure ◽  
Over Ground Walking

This study analyses the energy consumption of an active magnetorheological knee (AMRK) actuator that was designed for transfemoral prostheses. The system was developed as an operational motor unit (MU), which consists of an EC motor, a harmonic drive and a magnetorheological (MR) clutch, that operates in parallel with an MR brake. The dynamic models of the MR brake and MU were used to simulate the system’s energetic expenditure during over-ground walking under three different working conditions: using the complete AMRK; using just its motor-reducer, to operate as a common active knee prosthesis (CAKP), and using just the MR brake, to operate as a common semi-active knee prosthesis (CSAKP). The results are used to compare the MR devices power consumptions with that of the motor-reducer. As previously hypothesized, to use the MR brake in the swing phase is more energetically efficient than using the motor-reducer to drive the joint. Even if using the motor-reducer in regenerative braking mode during the stance phase, the differences in power consumption among the systems are remarkable. The AMRK expended 16.3 J during a gait cycle, which was 1.6 times less than the energy expenditure of the CAKP (26.6 J), whereas the CSAKP required just 6.0 J.

Operation Optimization Approaches of Thermal Power Units with Big Data-Driven Hybrid Modeling

2014 ◽  
Vol 631-632 ◽  
pp. 362-366
Author(s):  
Ning Ling Wang ◽  
Yong Zhang ◽  
Long Fei Zhu ◽  
Zhi Ping Yang
Keyword(s):  
Energy Consumption ◽  
Thermal Power ◽  
Hybrid Modeling ◽  
Data Driven ◽  
Fuzzy Rough Set ◽  
Operation Optimization ◽  
Operation Conditions ◽  
Energy Consumption Model ◽  
Practical Guidelines ◽  
Data Driven Modeling

An accurate and reliable energy-consumption model is the key to operation optimization and energy-saving diagnosis of thermal power units especially under different operation conditions and boundaries. Conventional mathematical and data-driven modeling methods were overviewed and compared in this paper. A hybrid modeling based on thermodynamic theory and fuzzy rough set (FRS) method was proposed to process the great volume of operation data and describe the energy-consumption behavior of thermal power units. On this basis, the operation optimization was performed with intelligent computation methods to derive the realizable benchmark state with the whole set of operation parameters. The resultant optimum operation state reflects the exterior factors and system behavior, taking practical guidelines for the modeling and optimization of large thermal power units.

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