Strength testing of low-cost 3D-printed transtibial prosthetic socket

Measurement and production of traditional prosthetic sockets are time-consuming, labor-intensive, and highly dependent on the personnel involved. An alternative way to make prostheses is using computer-aided design (CAD) and computer-aided manufacturing (CAM). Fused Filament Fabrication (FFF) may be an alternative to make low-cost prosthetic sockets. This study investigates the tensile properties of potential printing materials suitable for FFF according to ISO527 (Standard Test Method for Tensile Properties of Plastics). To ensure that FFF-printed sockets are safe for patient usage, the structural integrity of the 3D-printed prosthesis will be investigated according to ISO10328 (International Standard Structural Testing of Lower Limb Prostheses). Tough PLA was the most suitable print material according to ISO 527 testing. The Tough PLA printed socket completed 2.27 million cycles and a static test target value of 4025 N. Future research remains necessary to continue testing new potential materials, improve print settings, and improve the socket design for the production of FFF-printed transtibial prosthetic sockets. FFF using Tough PLA can be used to create transtibial prostheses that almost comply with the International Standard for Structural Testing of Lower Limb Prostheses.

Potential and Limitations of Feedback-Supported Gait Retraining in Users of Lower Limb Prostheses

The outcomes of prosthetic rehabilitation after lower limb loss are, in large part, affected by the effectiveness of the provided gait retraining. The noted prevalence of adverse long-term effects, such as further joint and muscle degeneration, suggests that traditional rehabilitation programs have limitations. Recent advances in technology and in the understanding of motor learning promise the potential for better gait retraining interventions. This article reviews current literature on systems and methodologies of improving gait parameters in those with lower limb prostheses via exercise programs and various biofeedback systems. A total of 13 articles were included in the qualitative analysis. Findings indicate that many of the investigated systems are able to effectively analyze and change gait in the target population, but there remain considerable gaps in the knowledge. It has been noted that feedback modalities and dosage must be customized based on patient characteristics and rehabilitation goals, yet there is currently not enough published evidence to inform such customization.

Semg Based Recognition Of Hand Motions For Lower Limb Prostheses

Aim: On multiple muscle locations, surface electromyography (sEMG) signals were recorded to predict the effect of different hand movements. Background: Myoelectric information is a non-stationary signal, so extracting correct features is important to boost any myoelectric control devices' performance. The myoelectric signal is an electrical activity recorded by a surface electrode at various movements of the muscles. Objective: The study presented pattern recognition classification methods to select an excellent algorithm for controlling the SEMG signal. Method: Various time domain and frequency domain parameters were extracted prior to conduct the classifier test. Result: For the evaluation of the results for the recorded data (of all six movements), confusion matrix for neural network, support vector machine (SVM), DT, and linear discriminant analysis (LDA) classifiers is presented. Conclusion: This present study will be a step in analyzing different problems for developing lower limb prostheses.

Prosthetic foot design with biomimetic ankle mechanism

This thesis proposes a novel lower-limb prosthetic device. Current prosthetics either have overly simplistic designs with inaccurate biomechanics or use delicate microprocessors that are easily damaged in harsh environments. This thesis aims to address these concerns by creating a novel device that combines a pneumatic damping system with a ball joint, resulting in a robust design with improved biomechanics. This prosthetic offers an affordable alternative that can be completely rebuilt while providing added comfort through improved biomechanics. Overall, this thesis contributes to the literature by proposing and discussing an innovative design for an affordable, comfortable, biomechanically sound alternative for lower limb prostheses.

A Cost-Effective Inertial Measurement System for Tracking Movement and Triggering Kinesthetic Feedback in Lower-Limb Prosthesis Users

Advances in lower-limb prosthetic technologies have facilitated the restoration of ambulation; however, users of such technologies still experience reduced balance control, also due to the absence of proprioceptive feedback. Recent efforts have demonstrated the ability to restore kinesthetic feedback in upper-limb prosthesis applications; however, technical solutions to trigger the required muscle vibration and provide automated feedback have not been explored for lower-limb prostheses. The study’s first objective was therefore to develop a feedback system capable of tracking lower-limb movement and automatically triggering a muscle vibrator to induce the kinesthetic illusion. The second objective was to investigate the developed system’s ability to provide kinesthetic feedback in a case participant. A low-cost, wireless feedback system, incorporating two inertial measurement units to trigger a muscle vibrator, was developed and tested in an individual with limb loss above the knee. Our system had a maximum communication delay of 50 ms and showed good tracking of Gaussian and sinusoidal movement profiles for velocities below 180 degrees per second (error < 8 degrees), mimicking stepping and walking, respectively. We demonstrated in the case participant that the developed feedback system can successfully elicit the kinesthetic illusion. Our work contributes to the integration of sensory feedback in lower-limb prostheses, to increase their use and functionality.