Tibial Motion Accuracy Using Circular Versus Noncircular Gears in Transfemoral Prosthetic Knees

2021 ◽  
pp. 44-51
Author(s):  
Wen-Tzong Lee ◽  
Kevin Russell
Keyword(s):  
Noncircular Gears ◽  
Prosthetic Knees

Choice of Noncircular Gears Hobbing Linkage Methods

2019 ◽  
Vol 13 (1) ◽  
pp. 69-74
Author(s):  
Wang Yazhou ◽  
Xiao Junfeng ◽  
Liu Yongping ◽  
An Jianmin
Keyword(s):  
Machine Tools ◽  
High Density ◽  
Arc Length ◽  
Linkage Methods ◽  
High Uniformity ◽  
Linkage Method ◽  
Noncircular Gears

Background: Various relevant patents and papers which have reported noncircular gears synthesize the advantages of circular gears and cam mechanisms, and are widely used in many types of mechanical instruments. Hobbing is a better method for fabricating noncircular gears. There are 4 linkagemethods to hob noncircular gears. However, which linkage method should be chosen practically has not yet been reported. Objective: The goal of this work is to choose the best linkage method for hobbing noncircular gears. Method: Firstly, the hobbing models of noncircular gears was deduced. Then, based on the model, hobbing linkage methods of noncircular gears were obtained. Thirdly, under different hobbing linkage methods, their aspects (developing regularity of hobbing cutter trace, arc length of program blocks and motion axes of machine tools) were compared. Results: Finally, with the best characteristics of a high density of shaping cutter trace, high uniformity of arc length of program blocks and ease of control, the equal arc-length of gear billet (EALGB) is obtained. It has been proven that EALGB is an excellent linkage method to hob noncircular gears. Conclusion: It has been proven that EALGB is an excellent linkage method to hob noncircular gears.

scholarly journals Manufacture of threads with variable pitch by using noncircular gears

2016 ◽  
Vol 147 ◽  
pp. 012009
Author(s):  
L Slătineanu ◽  
O Dodun ◽  
M Coteață ◽  
I Coman ◽  
G Nagîț ◽  
...  
Keyword(s):  
Variable Pitch ◽  
Noncircular Gears

Harnessing noncircular gears to achieve nonlinear passive springs

2019 ◽  
Vol 140 ◽  
pp. 434-445 ◽  
Author(s):  
Meng Li ◽  
Jinyou Li ◽  
Kangjia Fu ◽  
Anning Ye ◽  
Yong Xiao ◽  
...  
Keyword(s):  
Noncircular Gears

Educational Model for the Kinematic Study of Non-Circular Gears

2013 ◽  
Vol 332 ◽  
pp. 297-304
Author(s):  
Liviu Ciupitu
Keyword(s):  
Numerical Methods ◽  
Industrial Applications ◽  
Point Of View ◽  
Spur Gears ◽  
Test Rig ◽  
Educational Model ◽  
Educational Test ◽  
Kinematic Study ◽  
Variation Curve ◽  
Noncircular Gears

The noncircular gears are used more and more in industrial applications. The paper presents an educational test rig for the kinematic study of non-circular gears. Two gears are studied from kinematic theoretically point of view: a gear with identically oval spur gears and another gear with identically elliptical spur gears, and simulation diagrams are presented. As for the testing rig, a gear with identically oval spur gears has been used. The researchers are able to draw with high precision the variation curve of output angle with respect to input angle. By using numerical methods for integration and differentiation other diagrams could be drawn and a comparation with simulation diagrams could be made.

Reduced cortical brain activity with the use of microprocessor-controlled prosthetic knees during walking

2018 ◽  
Vol 43 (3) ◽  
pp. 257-265 ◽  
Author(s):  
Saffran Möller ◽  
David Rusaw ◽  
Kerstin Hagberg ◽  
Nerrolyn Ramstrand
Keyword(s):  
Cognitive Processes ◽  
Lower Limb ◽  
Brain Activity ◽  
Control Group ◽  
Healthy Controls ◽  
Prosthetic Knee ◽  
Level Walking ◽  
Lower Limb Prosthesis ◽  
Prosthetic Knees ◽  
Limb Prosthesis

Background: Individuals using a lower-limb prosthesis indicate that they need to concentrate on every step they take. Despite self-reports of increased cognitive demand, there is limited understanding of the link between cognitive processes and walking when using a lower-limb prosthesis. Objective: The objective was to assess cortical brain activity during level walking in individuals using different prosthetic knee components and compare them to healthy controls. It was hypothesized that the least activity would be observed in the healthy control group, followed by individuals using a microprocessor-controlled prosthetic knee and finally individuals using a non-microprocessor-controlled prosthetic knee. Study design: Cross-sectional study. Methods: An optical brain imaging system was used to measure relative changes in concentration of oxygenated and de-oxygenated haemoglobin in the frontal and motor cortices during level walking. The number of steps and time to walk 10 m was also recorded. The 6-min walk test was assessed as a measure of functional capacity. Results: Individuals with a transfemoral or knee-disarticulation amputation, using non-microprocessor-controlled prosthetic knee ( n = 14) or microprocessor-controlled prosthetic knee ( n = 15) joints and healthy controls ( n = 16) participated in the study. A significant increase was observed in cortical brain activity of individuals walking with a non-microprocessor-controlled prosthetic knee when compared to healthy controls ( p < 0.05) and individuals walking with an microprocessor-controlled prosthetic knee joint ( p < 0.05). Conclusion: Individuals walking with a non-microprocessor-controlled prosthetic knee demonstrated an increase in cortical brain activity compared to healthy individuals. Use of a microprocessor-controlled prosthetic knee was associated with less cortical brain activity than use of a non-microprocessor-controlled prosthetic knee. Clinical relevance Increased understanding of cognitive processes underlying walking when using different types of prosthetic knees can help to optimize selection of prosthetic components and provide an opportunity to enhance functioning with a prosthesis.

Design of Internal Noncircular Gears

2009 ◽  
pp. 115-137
Author(s):  
Faydor L. Litvin ◽  
Alfonso Fuentes-Aznar ◽  
Ignacio Gonzalez-Perez ◽  
Kenichi Hayasaka
Keyword(s):  
Noncircular Gears

scholarly journals Design of Vegetable Pot Seedling Pick-up Mechanism with Planetary Gear Train

2020 ◽  
Vol 33 (1) ◽  
Author(s):  
Zhipeng Tong ◽  
Gaohong Yu ◽  
Xiong Zhao ◽  
Pengfei Liu ◽  
Bingliang Ye
Keyword(s):  
Design Method ◽  
Planetary Gear ◽  
Gear Train ◽  
Dimensional Synthesis ◽  
Planetary Gear Train ◽  
Key Points ◽  
Physical Prototype ◽  
Noncircular Gears ◽  
Pitch Curve ◽  
Parameter Values

Abstract It has been challenging to design seedling pick-up mechanism based on given key points and trajectories, because it involves dimensional synthesis and rod length optimization. In this paper, the dimensional synthesis of seedling pick-up mechanism with planetary gear train was studied based on the data of given key points and the trajectory of the endpoint of seedling pick-up mechanism. Given the positions and orientations requirements of the five key points, the study first conducted a dimensional synthesis of the linkage size and center of rotation. The next steps were to select a reasonable solution and optimize the data values based on the ideal seedling trajectory. The link motion was driven by the planetary gear train of the two-stage gear. Four pitch curves of noncircular gears were obtained by calculating and distributing the transmission ratio according to the data. For the pitch curve with two convex points, the tooth profile design method of incomplete noncircular gear was applied. The seedling pick-up mechanism was tested by a virtual prototype and a physical prototype designed with the obtained parameter values. The results were consistent with the theoretical design requirements, confirming that the mechanism meets the expected requirements for picking seedlings up. This paper presents a new design method of vegetable pot seedling pick-up mechanism for an automatic vegetable transplanter.

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