scholarly journals Design method and verification of a hybrid prosthetic mechanism with energy-damper clutchable device for transfemoral amputees

2021 ◽  
Author(s):  
Majun Song ◽  
Sheng Guo ◽  
Anderson S. Oliveira ◽  
Xiangyang Wang ◽  
Haibo Qu
Keyword(s):  
Lower Extremity ◽  
Peak Power ◽  
Stance Phase ◽  
Design Method ◽  
Energy Coupling ◽  
Motion Energy ◽  
Transfemoral Amputees ◽  
Motion Characteristics ◽  
Mechanical Performances ◽  
Relationship Of

AbstractTransfemoral amputees (TAs) have difficulty in mobility during walking, such as restricted movement of lower extremity and body instability, yet few transfemoral prostheses have explored human-like multiple motion characteristics by simple structures to fit the kinesiology, biomechanics, and stability of human lower extremity. In this work, the configurations of transfemoral prosthetic mechanism are synthesized in terms of human lower-extremity kinesiology. A hybrid transfemoral prosthetic (HTP) mechanism with multigait functions is proposed to recover the gait functions of TAs. The kinematic and mechanical performances of the designed parallel mechanism are analyzed to verify their feasibility in transfemoral prosthetic mechanism. Inspired by motion—energy coupling relationship of the knee, a wearable energy-damper clutched device that can provide energy in knee stance flexion to facilitate the leg off from the ground and can impede the leg’s swing velocity for the next stance phase is proposed. Its co-operation with the springs in the prismatic pairs enables the prosthetic mechanism to have the energy recycling ability under the gait rhythm of the knee joint. Results demonstrate that the designed HTP mechanism can replace the motion functions of the knee and ankle to realize its multimode gait and effectively decrease the peak power of actuators from 94.74 to 137.05 W while maintaining a good mechanical adaptive stability.

Lower extremity joint kinematics of stair ascent in transfemoral amputees

2011 ◽  
Vol 35 (4) ◽  
pp. 467-472 ◽  
Author(s):  
Hiroaki Hobara ◽  
Yoshiyuki Kobayashi ◽  
Takashi Nakamura ◽  
Nobuya Yamasaki ◽  
Kimitaka Nakazawa ◽  
...  
Keyword(s):  
Knee Joint ◽  
Lower Extremity ◽  
Stance Phase ◽  
Reaction Force ◽  
Joint Kinematics ◽  
Whole Body ◽  
Prosthetic Knee ◽  
Stair Ascent ◽  
Transfemoral Amputees ◽  
Prosthetic Knee Joint

Background: Stair ascent is a very demanding task for transfemoral amputees (TFAs). The purpose of this study was to investigate the lower extremity joint kinematics of TFAs who can climb stairs using a step-over-step gait pattern without an active artificial prosthetic knee joint or handrail use. Case Description and Methods: Case series. Participants were two traumatic TFAs and 10 control participants. Both TFAs used a single-axis prosthetic knee joint in daily living. Sagittal plane joint kinematics were recorded at 60 Hz using an eight-camera motion analysis system and digital video camera. Findings and Outcomes: From the instant of touchdown, the prosthetic knee joint was rapidly extended and remained fully extended until toe-off. In the latter half of the stance phase, the knee and ankle joints of the sound limb simultaneously showed rapid joint flexion during continuous extension. Further, the ankle joint of the sound limb showed greater plantarflexion at the end of the stance phase. Conclusion: These results suggest that the TFA in the present study would (1) extend the prosthetic knee joint to prevent the knee flexion generated by the bodyweight (plus ground reaction force and/or joint moment), and (2) lift the whole body in an upward direction using strong counter-movements and greater joint extension during the stance phase.

AN OPTIMIZATION MODEL FOR PRELIMINARY STABILITY AND CONFIGURATION ANALYSES OF SEMI-SUBMERSIBLES

2021 ◽  
Vol 159 (A3) ◽  
Author(s):  
G D Gosain ◽  
R Sharma ◽  
Tae-wan Kim
Keyword(s):  
Optimization Model ◽  
Design Method ◽  
Optimization Techniques ◽  
Design Approach ◽  
Preliminary Design ◽  
Design Environment ◽  
Preliminary Stage ◽  
Steel Weight ◽  
Motion Characteristics ◽  
Almost All

In the modern era of design governed by economics and efficiency, the preliminary design of a semi-submersible is critically important because in an evolutionary design environment new designs evolve from the basic preliminary designs and the basic dimensions and configurations affect almost all the parameters related to the economics and efficiency (e.g. hydrodynamic response, stability, deck load and structural steel weight of the structure, etc.). The present paper is focused on exploring an optimum design method that aims not only at optimum motion characteristics but also optimum stability, manufacturing and operational efficiency. Our proposed method determines the most preferable optimum principal dimensions of a semi-submersible that satisfies the desired requirements for motion performance and stability at the preliminary stage of design. Our proposed design approach interlinks the mathematical design model with the global optimization techniques and this paper presents the preliminary design approach, the mathematical model of optimization. Finally, a real world design example of a semi-submersible is presented to show the applicability and efficiency of the proposed design optimization model at the preliminary stage of design.

A Design Method of Rain Test Device Based on Water Drop Motion Simulation

2013 ◽  
Vol 871 ◽  
pp. 363-368
Author(s):  
Hong Tao Zeng ◽  
Lin Lin Lin ◽  
Cong Feng ◽  
Zhi Huai Xiao
Keyword(s):  
Design Method ◽  
Water Drop ◽  
Electrical Equipment ◽  
Simulation Software ◽  
Test Device ◽  
Rainy Weather ◽  
Drop Motion ◽  
Water Drops ◽  
Motion Characteristics ◽  
Insulation Performance

In order to measure the electric insulation performance of the electrical equipment in rainy weather, its essential to design a rain device to simulate different conditions of rainfall. In this paper, a motion model of raindrop sprayed by the rain device and differential equations describing its motion characteristics are built. Basing on the analysis of water drop motion, a set of simulation software is developed for the selection of rain test device and the analysis of test results. The software can simulate the water drops motion process from nozzle to test equipment, and the simulation results is almost the same with field test, so the simulation software provides the basis for the design of rain test device.

Design and analysis of a propulsion mechanism using modular umbrella-like wings

2018 ◽  
Vol 122 (1249) ◽  
pp. 349-368
Author(s):  
F. Gao ◽  
J. G. Lv ◽  
X. C. Zhang
Keyword(s):  
Structural Model ◽  
Aerodynamic Force ◽  
Inertial Force ◽  
Structure Design ◽  
Symmetrical Structure ◽  
Propulsion Mechanism ◽  
New Type ◽  
Practical Guidance ◽  
Mechanical Performances ◽  
Relationship Of

ABSTRACTThis article describes the design and evaluation of a new type of propulsion mechanism that uses modular umbrella-like wings oscillating symmetrically in counterphase to generate thrust. The principle of the propulsion and movement of the modular umbrella-like wings was first developed, and the mechanism used to implement the movement of the modular wings was subsequently designed. A structural model and the assembly relationship of the propulsion mechanism were developed for prototype fabrication. An experiment was established to measure the kinematic and mechanical performances of the propulsion mechanism for different reciprocating frequencies and travels. The results for the single umbrella-like wing indicate that either increasing the frequency or enlarging the travel can enhance the average aerodynamic force generated by the wing in one cycle. The results for the modular umbrella-like wings demonstrate that the inertial force generated by the mechanism can be balanced using a symmetrical structure. The average aerodynamic force would be markedly enhanced by increasing the percentage of the time that the outspread wing is moving downwards; e.g. the average aerodynamic force generated by the modular umbrella-like wings was increased by 85.84% compared to the value for a single umbrella-like wing for the same travel and frequency. This work provides practical guidance for optimising the structure design.

Design Method of Reducer Oriented Maintenance

2010 ◽  
Vol 108-111 ◽  
pp. 1129-1133
Author(s):  
Wan Jing Ding
Keyword(s):  
Design Method ◽  
Product Lifecycle Management ◽  
Relationship Matrix ◽  
Product Lifecycle ◽  
Basic Principles ◽  
Disassembly Sequence ◽  
The Matrix ◽  
Machine Industry ◽  
Relationship Of ◽  
Lifecycle Management

Maintenance is an important part of the product lifecycle management. As important equipment widely used in machine industry, disassembly and maintenance of reducer is crucial. In this paper, according to position and assembly relationship of all parts of reducer in 3D and the basic principles of disassembly, a disassembly relationship matrix was defined. The matrix can well express the disassemblity of the every part in model. Then, a generation algorithm of disassembly sequence was proposed based on and operations. Finally disassembly sequence of reducer was generated in VB.

Optimization Analysis on Gyroscope’s Three Dimensions Complicated Motion and Lash-Force

2014 ◽  
Vol 945-949 ◽  
pp. 581-586
Author(s):  
Wen Li Yang ◽  
Xiang Hui Lu
Keyword(s):  
Nonlinear Differential Equations ◽  
Three Dimensional ◽  
Three Dimensions ◽  
Optimization Analysis ◽  
Motion Equations ◽  
Sliding Motion ◽  
Motion State ◽  
Motion Characteristics ◽  
Force Time ◽  
Relationship Of

The complicated motion of the gyroscope includes the rotation, the precession, the nutation and the sliding motion which are coupled, and it is affected by the lash-force by the whip. Taking the gyroscope which is moving stably as the research subject, according to the motion characteristics of the gyro’s rotation and precession, the gyro is assumed to be the two-force bar, and the coupled relationship of the gyroscope is analyzed quantitatively. The three-dimensional complicated motion in the different categories is analyzed. The nonlinear differential equations in the different categories is derived and linearized by the minor variables method, and then the three-dimensional motion equations on the rotation, precession, nutation and slipping of the gyroscope in the different categories is established. Take the big gym gyroscope as the example, the influence of the force, time and position of the whip on the motion state of the gyroscope is analyzed in detail, and provides the basis for the design of the gyroscope.

Lower-Extremity Motor Synergies in Individuals With and Without Chronic Ankle Instability

2020 ◽  
Vol 36 (6) ◽  
pp. 416-422
Author(s):  
Adam E. Jagodinsky ◽  
Rebecca Angles ◽  
Christopher Wilburn ◽  
Wendi H. Weimar
Keyword(s):  
Lower Extremity ◽  
Stance Phase ◽  
Ankle Instability ◽  
Theoretical Models ◽  
Chronic Ankle Instability ◽  
Healthy Individuals ◽  
Motor Synergies ◽  
Load Response ◽  
Motor Synergy ◽  
The Moment

Current theoretical models suggest that ankle sprain copers exhibit movement adaptations contributing to the avoidance of chronic ankle instability. However, few studies have examined adaptations at the level of biomechanical motor synergies. The purpose was to examine characteristics of the support moment synergy between individuals with chronic ankle instability, copers, and healthy individuals. A total of 48 individuals participated in the study. Lower-extremity kinetics and variability in the moment of force patterns were assessed during the stance phase of walking trials. The copers exhibited reductions in the support moment during the load response and preswing phase compared with the chronic ankle instability group, as well as during the terminal stance and preswing phase compared the healthy group. The copers also exhibited reductions in the hip extensor moment and ankle plantarflexion moment compared with healthy and chronic ankle instability groups during intervals of stance phase. Variability of the support moment and knee moment was greater in the copers compared with the chronic ankle instability group. Dampening of the support moment and select joint moments exhibited by the copers may indicate an adaptive mechanism to mitigate loading perturbations on the previously injured ankle. Heightened motor variability in copers may be indicative of a more adaptable motor synergy compared with individuals with chronic ankle instability.

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