Adjusting Ankle Angle Measurement Based on a Strain Gauge Bridge for Powered Transtibial Prosthesis

2020 ◽  
Vol 142 (7) ◽  
Author(s):  
Yanggang Feng ◽  
Qining Wang

Abstract Inaccurate ankle angle measurement may affect gait event detection accuracy, control parameter precision and assessment validity, and even finally result in gait asymmetry. This paper proposed an adjustment method based on a strain gauge bridge to obtain accurate ankle joint angle measurement for a powered transtibial prosthesis. The characteristics of relative creep, hysteresis, and temperature were studied. Then the curving fitting was used to study the relationship between the measured value of the strain gauge bridge and the compensation angle. Three male transtibial amputees participated in the experiments. Experimental results show that the strain gauge bridge can sense the deformation of carbon-fiber footplate, and be utilized to adjust the ankle angle. The effects of an inaccurate ankle angle were further discussed.

2016 ◽  
Vol 29 (4) ◽  
pp. 465-473 ◽  
Author(s):  
Na Jin Seo ◽  
Mojtaba F. Fathi ◽  
Pilwon Hur ◽  
Vincent Crocher

2007 ◽  
Vol 342-343 ◽  
pp. 621-624
Author(s):  
Hyeon Ki Choi ◽  
Si Yeol Kim ◽  
Won Hak Cho

We investigated the relationship between kinematic and kinetic characteristics of foot joints resisting ground reaction force (GRF). Passive elastic characteristics of joint were obtained from the experiment using three cameras and one force plate. The relationship between joint angle and moment was mathematically modeled by using least square method. The calculated ranges of motion were 7o for TM joint, 4o for TT joint and 20o for MP joint. With the model that relates joint angle and plantar pressure, we could get the kinematic data of the joints which are not available from conventional motion analysis. The model can be used not only for biomechanical analysis which simulates gait but also for the clinical evaluations.


1984 ◽  
Vol 21 (04) ◽  
pp. 384-388
Author(s):  
John C. Clements

This work is concerned with the application of a new isometric mapping algorithm to hull plate expansion procedures for ships with all or portions of the hull consisting of developable surfaces. The expansion procedure is based on the relationship between the ruling lines r⇀(s) generating the developable surface S⇀(s,t) and one additional geodesic g⇀(s) constructed within the surface as the solution of the differential equation det(g⇀'g⇀"n⇀) = 0 where n⇀ is the unit normal to S⇀ at g⇀. Precise accuracy control is achieved through the use of adaptive numerical quadrature and a variable stepsize differential equation solving routine.


Author(s):  
Lixin Wang ◽  
Pan Pan ◽  
Shixing Yan ◽  
Shiyun Dong

The slippery zone of Nepenthes alata depends on its highly evolved morphology and structure to show remarkable superhydrophobicity, which has gradually become a biomimetic prototype for developing superhydrophobic materials. However, the mechanism governing this phenomenon has not been fully revealed through model analysis. In this paper, the superhydrophobicity of slippery zone is studied by contact angle measurement, morphology/structure examination and model analysis. The slippery zone causes ultrapure water droplet to produce a considerably high contact angle (155.11–158.30°), and has a micro-nano scale hierarchical structures consisting of lunate cells and wax coverings. According to the Cassie-Baxter equation and a self-defined infiltration coefficient, a model was established to analyze the effect of structure characteristic on the contact angle. Analysis result showed that the calculated contact angle (154.67–159.49°) was highly consistent with the measured contact angle, indicating that the established model can quantitatively characterize the relationship between the contact angle and the structure characteristic. Our study provides some evidences to further reveal the superhydrophobic mechanism of Nepenthes alata slippery zone, as well as inspires the biomimetic development of superhydrophobic surfaces.


Sensors ◽  
2018 ◽  
Vol 18 (9) ◽  
pp. 3043 ◽  
Author(s):  
Weike Zhang ◽  
Xi Chen ◽  
Kaibo Cui ◽  
Tao Xie ◽  
Naichang Yuan

In order to improve the angle measurement performance of a coprime linear array, this paper proposes a novel direction-of-arrival (DOA) estimation algorithm for a coprime linear array based on the multiple invariance estimation of signal parameters via rotational invariance techniques (MI-ESPRIT) and a lookup table method. The proposed algorithm does not require a spatial spectrum search and uses a lookup table to solve ambiguity, which reduces the computational complexity. To fully use the subarray elements, the DOA estimation precision is higher compared with existing algorithms. Moreover, the algorithm avoids the matching error when multiple signals exist by using the relationship between the signal subspace of two subarrays. Simulation results verify the effectiveness of the proposed algorithm.


2006 ◽  
Vol 326-328 ◽  
pp. 237-240 ◽  
Author(s):  
Yasushi Sasaki ◽  
Manabu Iguchi ◽  
Mitsutaka Hino

Based on the relationship between quantified blurring degree of Kikuchi bands obtained by an electron backscattering diffraction (EBSD) technique and macroscopic strains measured by a strain gauge, the local compression strain SEBSD in sinter ore has been evaluated under various conditions. There is a good linear relationship between the SEBSD and the strains measured by a strain gauge. The local strain SEBSD evaluated by EBSD patterns can be used as an index of local strains.


2021 ◽  
Author(s):  
Rongguo Song ◽  
Zelong Hu ◽  
Shaoqiu Jiang ◽  
Li Ma ◽  
Qingsong Ai ◽  
...  

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