1,086 research outputs found

    A Generalized Method for Predictive Simulation-Based Lower Limb Prosthesis Design

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    Lower limb prostheses are designed to replace the functions and form of the missing biological anatomy. These functions are hypothesized to improve user outcome measures which are negatively affected by receiving an amputation – such as metabolic cost of transport, preferred walking speed, and perceived discomfort during walking. However, the effect of these design functions on the targeted outcome measures is highly variable, suggesting that these relationships are not fully understood. Biomechanics simulation and modeling tools are increasingly capable of analyzing the effects of a design on the resulting user gait. In this work, prothesis-aided gait is optimized in simulation to reduce both muscle effort and peak loads on the residual limb using a generalized prosthesis model. Compared to a traditional revolute powered ankle joint model, a two degree-of freedom generalized model reduced muscle activations by 50% and peak loads by 15%. Simulated prosthesis behaviors corresponding to the optimal gait patterns were translated into a two degree-of-freedom ankle-foot prosthesis design with powered bidirectional linear translation and plantarflexion. The prototype is capable of delivering up to 171 N-m of plantarflexion torque and 499 N of translation force, with 15° dorsi-/35° plantarflexion and 10 cm translation range of motion. The mass and height of the ankle-foot are 2.29 kg and 19.5 cm, respectively. The mass of the entire system including the wearable offboard system is 8.58 kg. This platform is designed to emulate the behavior of the simulated prosthesis, as well as be configurable to emulate alternate behaviors obtained from simulations with different optimization objectives. The prototype is controlled to replicate simulated walking patterns using a high level finite state controller, mid-level stiffness controller, and low level load controller. Closed loop load control has bandwidth of 15 Hz in translation and 7.2 Hz in flexion. Load tracking during walking with a single able-bodied human subject ranges from 93 to 159 N in translation and 4.6 to 21.3 N-m in flexion. The contribution of this work is to provide a framework for predictive simulation-based prosthesis design, evidence of its practical implementation, and the experimental tools to validate future predictive simulation studies

    Design, Modeling, and Control of an Active Prosthetic Knee

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    The few microcontroller based active/semi-active prosthetic knee joints available commercially are extremely expensive and do not consider the uncertainties of inputs sensory information. Progressing in the controller of the current prosthetic devices and creating artificial lower limbs compatible with different users may lead to more effective and low-cost prostheses. This can affect the life style of lots of amputees specially the land-mine victims in developing war-torn countries who are unable to partake in the advancement of the current intelligent prosthetic knees. The purpose of the proposed Active Prosthetic Knee (APK) design is to investigate a new schema that allows the device to provide the full necessary torque at the knee joint based on echoing the state of the intact leg. This study involves the design features of the mechanical aspects, sensing system, communication, and knowledge-based controller to implement a cost-effective APK. The proposed microcontroller based prosthesis utilizes a ball screw system accompanied by a high-speed brushed servomotor to provide one degree of freedom for the fabricated prototype. Moreover, a modular test-bed is manufactured to mimic the lower limb motion which contributes investigating different controllers for the prototype. Thus, the test bed allows assessing the primary performance of the APK before testing on a human subject. Different types of sensing systems (electromyography and lower limb inclination angles) are investigated to extract signals from the user’s healthy leg and send the captured data to the APK controller. The methodology to measure each type of signal is described, and comparison analyses are provided. Wireless communication between the sensory part and actuator is established. A knowledge-based control mechanism is developed that takes advantage of an Adaptive-Network-based Fuzzy Inference System (ANFIS) to determine knee torque as a function of the echoing angular state of the able leg considering the uncertainty of inputs. Therefore, the developed controller can make the APK serviceable for different users. The fuzzy membership function’s parameters and rules define the knowledge-base of the system. This knowledge is based on existing experience and known facts about the walking cycle

    Effects of Physical Exertion and Alignment Alterations on Trans-Tibial Amputee Gait, and Concurrent Validity of Prosthesis-Integrated Measurement of Gait Kinetics

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    This study investigated the effects of slight changes in the alignment of the artificial limb of trans-tibial amputees on the walking pattern on the level of forces and moments, particularly when physical exertion levels increase. Two alignment conditions were assessed in ten trans-tibial amputees while walking with low and with strong levels of exertion. Two separate data collection methods were utilized simultaneously: a conventional motion analysis, and continuous recordings from prosthesis-integrated force sensors. While the former was used to compare bilateral leg symmetry across conditions, the latter allowed analyzing unilateral step variability within subjects. This paper presents both analyses in separate chapters. A third chapter addresses the question of concurrent validity of the utilized integrated-sensor-based gait data collection method. Findings indicate that increased physical exertion and prosthesis ankle plantar-flexion angle was related to decreases in step length symmetry, maximal knee flexion angle, knee moment, and dorsi-flexion moment, but had no significant effect on an overall gait symmetry index. It was also shown, that effects were different among participants, with only three of them showing a significant change in parameters measured by the integrated sensor system. Integrated sensor measurements namely of axial force and joint moments were found to be closely correlated to conventional measurements, while pertaining to slightly different biomechanical quantities. The detected effects of alignment perturbations and physical exertion were small in magnitude and inconsistent between participants of our sample population. The concept of a range of acceptable prosthesis alignments, within which no optimization is feasible, is supported. However, amputee gait pattern and responses to alignment perturbations seem to change with the level of exertion. This suggests a consideration of real life conditions for the individual optimization of prosthetic alignment. Provided the systematic limitations of the integrated sensor measurements are carefully considered, it appears possible to use this method for the assessment of individual effects of alignment changes

    International Conference on Mechatronics, System Engineering And Robotics & Informations System And Engineering

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    UBT Annual International Conference is the 9th international interdisciplinary peer reviewed conference which publishes works of the scientists as well as practitioners in the area where UBT is active in Education, Research and Development. The UBT aims to implement an integrated strategy to establish itself as an internationally competitive, research-intensive university, committed to the transfer of knowledge and the provision of a world-class education to the most talented students from all background. The main perspective of the conference is to connect the scientists and practitioners from different disciplines in the same place and make them be aware of the recent advancements in different research fields, and provide them with a unique forum to share their experiences. It is also the place to support the new academic staff for doing research and publish their work in international standard level. This conference consists of sub conferences in different fields like: Art and Digital Media Agriculture, Food Science and Technology Architecture and Spatial Planning Civil Engineering, Infrastructure and Environment Computer Science and Communication Engineering Dental Sciences Education and Development Energy Efficiency Engineering Integrated Design Information Systems and Security Journalism, Media and Communication Law Language and Culture Management, Business and Economics Modern Music, Digital Production and Management Medicine and Nursing Mechatronics, System Engineering and Robotics Pharmaceutical and Natural Sciences Political Science Psychology Sport, Health and Society Security Studies This conference is the major scientific event of the UBT. It is organizing annually and always in cooperation with the partner universities from the region and Europe. We have to thank all Authors, partners, sponsors and also the conference organizing team making this event a real international scientific event. Edmond Hajrizi, President of UBT UBT – Higher Education Institutio

    A powered prosthetic ankle joint for walking and running

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    A course in orthopedic nursing to be used in the basic nursing program of "X" School of Nursing

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    Thesis (M.S.)--Boston University, 1947. This item was digitized by the Internet Archive

    Rehabilitation Technologies: Biomechatronics Point of View

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