scholarly journals Analysis of Stiffness and Energy Consumption of Nonlinear Elastic Joint Legged Robot

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Dongliang Chen ◽  
Jindong Zhang ◽  
Xutao Weng ◽  
Yunjian Zhang ◽  
Zhonghui Shi
Keyword(s):  
Energy Consumption ◽  
Variable Stiffness ◽  
Legged Robot ◽  
Spring Stiffness ◽  
Simulation Experiments ◽  
Torsion Spring ◽  
Elastic Joint ◽  
Output Torque ◽  
Nonlinear Elastic ◽  
Elastic Unit

In order to reduce the energy consumption of the legged robot in walking, this paper designs a kind of nonlinear elastic joint from the flexible variable-stiffness joint based on the mammal walking on the limb and optimizes the leg structure of the legged robot. The motor is rigidly connected to the articulated lever. When the lever is accelerated or decelerated, the elastic unit is introduced. The system can be considered as a special variable-rate elastic system. This paper will study it from theory and simulation experiments. Based on the dynamic analysis, a functional relationship between the output torque and the torsion spring stiffness and between the energy consumption and the torsion spring stiffness was established. By finding the extremum, the two optimum torsional spring stiffness that can minimize the required output average torque and the energy consumed during one cycle of motion were deduced. The results show that using this design in a reasonable position can effectively reduce the energy consumption of the system and can achieve up to a 50% reduction in energy consumption.

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 Secure and Low Energy Consumption Range Query in Tiered Sensor Networks

2016 ◽  
Vol 12 (07) ◽  
pp. 4 ◽  
Author(s):  
Song Ling ◽  
Qi Dong Yang
Keyword(s):  
Wireless Sensor Networks ◽  
Energy Consumption ◽  
Sensor Networks ◽  
Value Chain ◽  
Range Query ◽  
Privacy Preserving ◽  
Low Energy ◽  
Wireless Sensor ◽  
Simulation Experiments ◽  
Low Energy Consumption

For the requirement of low energy consumption and high privacy-preserving in wireless sensor networks of range query, we propose a low energy consumption secure and verifiable range query protocol called SPRQ.SPRQ uses a novel prime aggregation to protect the privacy of the query data; We further propose an idea of the and value chain whereby data items collected by each sensor will be linked with each other just like a chain.The Sink verifies the integrity of query results by checking whether the data chain of each sensor is complete or not. The results of simulation experiments prove that prime aggregation can effectively reduce the amount of increased data in the prefix encoding process,so,network energy consumption is lower compared with other secure range query protocols.

scholarly journals Conceptual mechanical design of antagonistic variable stiffness joint based on equivalent quadratic torsion spring

2020 ◽  
Vol 103 (3) ◽  
pp. 003685042094129
Author(s):  
Jishu Guo
Keyword(s):  
Degrees Of Freedom ◽  
Modular Design ◽  
Angular Displacement ◽  
Variable Stiffness ◽  
Human Robot Interaction ◽  
Design Calculation ◽  
Robot Arm ◽  
Compact Structure ◽  
Torsion Spring ◽  
Stiffness Characteristics

The variable stiffness joint is a kind of flexible actuator with variable stiffness characteristics suitable for physical human–robot interaction applications. In the existing variable stiffness joints, the antagonistic variable stiffness joint has the advantages of simple implementation of variable stiffness mechanism and easy modular design of the nonlinear elastic element. The variable stiffness characteristics of antagonistic variable stiffness joints are realized by the antagonistic actuation of two nonlinear springs. A novel design scheme of the equivalent nonlinear torsion spring with compact structure, large angular displacement range, and desired stiffness characteristics is presented in this article. The design calculation for the equivalent quadratic torsion spring is given as an example, and the actuation characteristics of the antagonistic variable stiffness joint based on the equivalent quadratic torsion spring are illustrated. Based on the design idea of constructing the antagonistic variable stiffness joint with compact structure and high compliance, as well as the different design requirements of the joints at different positions of the multi–degrees of freedom robot arm, nine types of mechanical schemes of antagonistic variable stiffness joint with the open design concept are proposed in this article. Finally, the conceptual joint configuration schemes of the robot arm based on the antagonistic variable stiffness joint show the application scheme of the designed antagonistic variable stiffness joint in the multi–degrees of freedom robot.

scholarly journals Design, Development and Scaling Analysis of a Variable Stiffness Magnetic Torsion Spring

10.5772/57300 ◽  
2013 ◽  
Vol 10 (10) ◽  
pp. 372 ◽  
Author(s):  
Angelo Sudano ◽  
Dino Accoto ◽  
Loredana Zollo ◽  
Eugenio Guglielmelli
Keyword(s):  
Variable Stiffness ◽  
Scaling Analysis ◽  
Design Development ◽  
Torsion Spring

scholarly journals Theoretical Study of Memristor and \\ Time Reversal based\\ Nonlinear Elastic Wave Spectroscopy

2018 ◽  
Author(s):  
Sadataka Furui ◽  
Serge Dos Santos
Keyword(s):  
Elastic Wave ◽  
Time Reversal ◽  
Theoretical Study ◽  
Chaotic Oscillation ◽  
Acoustic Tomography ◽  
Linear Elastic ◽  
Strong Signal ◽  
Nonlinear Elastic ◽  
Nonlinear Elastic Wave ◽  
Elastic Unit

Principle of memristor presented by Leon Chua and time reversal based non-linear elastic wave spectroscopy (TR-NEWS) which can be applied to acoustic tomography are reviewed. Correlation of acoustic or electromagnetic nonlinear waves and its time reversed wave can produce strong signal. Materials like transducer or biological skin can be assumed to be composed of a large number of small elastic unit: hysteretic elementary unit (HEU), and one can take a HEU as a memristor whose operation depends on time. Relation between TR-NEWS and solitonic wave in fluid, and relation between decomposition of time reversal operator (DORT) and chaotic oscillation are discussed.

G1501-2-3 A multi legged-robot with a little energy consumption

2009 ◽  
Vol 2009.5 (0) ◽  
pp. 145-146
Author(s):  
Tyo KAWAMURA ◽  
Yoshihiro HAGIHARA ◽  
Akira HASHIMOTO ◽  
Yukari HAGIHARA
Keyword(s):  
Energy Consumption ◽  
Legged Robot
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