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Detection of Prosthetic Knee Movement Phases via In-Socket Sensors: A Feasibility Study.

El-Sayed AM, Hamzaid NA, Tan KY, Abu Osman NA - ScientificWorldJournal (2015)

Bottom Line: In contrast, FSR could estimate the gait cycle stance and swing phases and identify the pre-full standing at sit to stand.FSR showed less variation during sit to stand and stair ascent to sensitively represent the different movement states.In addition, it validated the efficacy of the system and warrants further investigation with more amputee subjects and different sockets types.

View Article: PubMed Central - PubMed

Affiliation: Department of Biomedical Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur, Malaysia ; Mechatronics Section, Mechanical Engineering Department, Faculty of Engineering, Assiut University, Assiut 71516, Egypt.

ABSTRACT
This paper presents an approach of identifying prosthetic knee movements through pattern recognition of mechanical responses at the internal socket's wall. A quadrilateral double socket was custom made and instrumented with two force sensing resistors (FSR) attached to specific anterior and posterior sites of the socket's wall. A second setup was established by attaching three piezoelectric sensors at the anterior distal, anterior proximal, and posterior sites. Gait cycle and locomotion movements such as stair ascent and sit to stand were adopted to characterize the validity of the technique. FSR and piezoelectric outputs were measured with reference to the knee angle during each phase. Piezoelectric sensors could identify the movement of midswing and terminal swing, pre-full standing, pull-up at gait, sit to stand, and stair ascent. In contrast, FSR could estimate the gait cycle stance and swing phases and identify the pre-full standing at sit to stand. FSR showed less variation during sit to stand and stair ascent to sensitively represent the different movement states. The study highlighted the capacity of using in-socket sensors for knee movement identification. In addition, it validated the efficacy of the system and warrants further investigation with more amputee subjects and different sockets types.

No MeSH data available.


FSR and piezoelectric sensors output during stair ascent: (a) FSR anterior, piezo anterior distal, and piezo anterior proximal sites, (b) FSR and piezoelectric sensors at posterior sites, (c) knee angle during stride, and (d) piezoelectric sensors with the knee angle at a region from 20% to 60%.
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Related In: Results  -  Collection


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fig9: FSR and piezoelectric sensors output during stair ascent: (a) FSR anterior, piezo anterior distal, and piezo anterior proximal sites, (b) FSR and piezoelectric sensors at posterior sites, (c) knee angle during stride, and (d) piezoelectric sensors with the knee angle at a region from 20% to 60%.

Mentions: Stair ascending was carried out as shown in Figure 9. The foot was placed on the step as shown in Figure 9 before the measurement of knee angle and sensors is started. As illustrated in the graph, the output voltage of both anterior and posterior sensors remains almost constant during the whole event because of the pressure generated from the ground, which is directly reflected as voltage of about 3–3.2 V. The knee angle varied from 23° to 9° at the end of the stair ascent phase. Stair ascent movement was conducted with the user wearing the socket embedded with the piezoelectric sensors. The knee angle decreases gradually from about 23° to 8°; however the variation of the output signals from piezoelectric sensor at both anterior distal and posterior proximal sensors changed minimally during the 0% to 60% stride. Piezoelectric sensor at the posterior site decompressed at the early stage of the stride at 10%. High compression value was noticed at anterior distal site which has a value of about 1.5 V (Figure 9). In overall, Figure 9(d) shows the three piezoelectric signals with the knee angle in the same graph. It can be noticed that the fluctuations of the piezoelectric sensors agreed at a region starting from 20% to 60%. This region can provide information when compared with the variation of the knee angle which starts from 15° to almost 10°.


Detection of Prosthetic Knee Movement Phases via In-Socket Sensors: A Feasibility Study.

El-Sayed AM, Hamzaid NA, Tan KY, Abu Osman NA - ScientificWorldJournal (2015)

FSR and piezoelectric sensors output during stair ascent: (a) FSR anterior, piezo anterior distal, and piezo anterior proximal sites, (b) FSR and piezoelectric sensors at posterior sites, (c) knee angle during stride, and (d) piezoelectric sensors with the knee angle at a region from 20% to 60%.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4402191&req=5

fig9: FSR and piezoelectric sensors output during stair ascent: (a) FSR anterior, piezo anterior distal, and piezo anterior proximal sites, (b) FSR and piezoelectric sensors at posterior sites, (c) knee angle during stride, and (d) piezoelectric sensors with the knee angle at a region from 20% to 60%.
Mentions: Stair ascending was carried out as shown in Figure 9. The foot was placed on the step as shown in Figure 9 before the measurement of knee angle and sensors is started. As illustrated in the graph, the output voltage of both anterior and posterior sensors remains almost constant during the whole event because of the pressure generated from the ground, which is directly reflected as voltage of about 3–3.2 V. The knee angle varied from 23° to 9° at the end of the stair ascent phase. Stair ascent movement was conducted with the user wearing the socket embedded with the piezoelectric sensors. The knee angle decreases gradually from about 23° to 8°; however the variation of the output signals from piezoelectric sensor at both anterior distal and posterior proximal sensors changed minimally during the 0% to 60% stride. Piezoelectric sensor at the posterior site decompressed at the early stage of the stride at 10%. High compression value was noticed at anterior distal site which has a value of about 1.5 V (Figure 9). In overall, Figure 9(d) shows the three piezoelectric signals with the knee angle in the same graph. It can be noticed that the fluctuations of the piezoelectric sensors agreed at a region starting from 20% to 60%. This region can provide information when compared with the variation of the knee angle which starts from 15° to almost 10°.

Bottom Line: In contrast, FSR could estimate the gait cycle stance and swing phases and identify the pre-full standing at sit to stand.FSR showed less variation during sit to stand and stair ascent to sensitively represent the different movement states.In addition, it validated the efficacy of the system and warrants further investigation with more amputee subjects and different sockets types.

View Article: PubMed Central - PubMed

Affiliation: Department of Biomedical Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur, Malaysia ; Mechatronics Section, Mechanical Engineering Department, Faculty of Engineering, Assiut University, Assiut 71516, Egypt.

ABSTRACT
This paper presents an approach of identifying prosthetic knee movements through pattern recognition of mechanical responses at the internal socket's wall. A quadrilateral double socket was custom made and instrumented with two force sensing resistors (FSR) attached to specific anterior and posterior sites of the socket's wall. A second setup was established by attaching three piezoelectric sensors at the anterior distal, anterior proximal, and posterior sites. Gait cycle and locomotion movements such as stair ascent and sit to stand were adopted to characterize the validity of the technique. FSR and piezoelectric outputs were measured with reference to the knee angle during each phase. Piezoelectric sensors could identify the movement of midswing and terminal swing, pre-full standing, pull-up at gait, sit to stand, and stair ascent. In contrast, FSR could estimate the gait cycle stance and swing phases and identify the pre-full standing at sit to stand. FSR showed less variation during sit to stand and stair ascent to sensitively represent the different movement states. The study highlighted the capacity of using in-socket sensors for knee movement identification. In addition, it validated the efficacy of the system and warrants further investigation with more amputee subjects and different sockets types.

No MeSH data available.