AN APPROACH FOR QUANTITATIVE EVALUATION OF TRANSFEMORAL PROSTHESIS SOCKET BY FINITE ELEMENT ANALYSIS

Objective: The correct shaping of the socket for appropriate load distribution is a critical process in the design of lower limb prosthesis sockets.Several studies have been conducted to disclose these parameters; they can be divided into two methods: Experiment method and computationmethod. The finite element (FE) analysis has highly effective for study the interface pressure between the residual limb and socket. However, there isa little study focus on creating separate models of the socket and residual limb. Almost research using the same shape of socket and residual limb orusing the unreal model of the socket. This study will be given some solutions for the above issues.Methods: The author creates two models of the residual limb: Same and different with the shape of the socket. After that, the FE models weregenerated with appropriate conditions of the donning process. The experimental procedure was conducted for comparison and discussion with theresults of the simulation.Results: The results in case of different shape of socket and residual limb suggest that it is the better model for evaluating the interface pressure.Conclusions: The procedure developed through this work can be used by future researchers and prosthesis designers in understanding how to betterdesign the socket and transfemoral prostheses

Development of an Evaluation System for Magnetic Resonance Imaging Based Three-Dimensional Modeling of a Transfemoral Prosthetic Socket Using Finite Elements

Recent technologies have suggested the utilization of three-dimensional (3D) printingtechnology to enhance the fabrication accuracy of prosthetics. Accordingly, simulations are used toobtain precise parameters for subject-specified prosthetic socket. This study proposes an evaluationsystem to measure the accuracy of a subject-specific 3D transfemoral residuum model duringthe interaction with the socket in conjunction with the application of finite element methods.The proposed system can be used in future validations of socket fabrication. The evaluation isbased on the measurement of the residuum’s soft tissue deformation inside two types of prostheticsockets. In comparison with other studies, the 3D models were constructed with magnetic resonanceimages (MRI) with the aid of computer-aided design (CAD) software. The measurement of soft tissuedeformation was conducted based on the measurement of the volumetric value of fat, muscle andskin in the pre- and post-donning phases. The result yielded a promising correlation coefficient valuebetween the simulation and the experiment in the soft tissue deformation evaluation. The relationof the muscle–fat ratio in the residuum is extremely important in the determination of the abilityof the prosthetic to deform. The environment during the socket fitting session was similar to thatdefined by the set boundary conditions in simulations. In view of the promising results of thisstudy, the evaluation system proposed herein is considered reliable and is envisaged to be used infuture research

Development and Control of Hand Exoskeleton System Using Intended Movement

Hand motor impairment is a common disability among stroke survivors that severely affect their ability in activities of daily livings (ADLs), reducing independence and quality of life. Throughout the rehabilitation process, stroke patients able to regain partially or fully the hand motor function. However, the conventional rehabilitation process is limited by the insufficient number of therapists, labor-intensiveness, and low compliance. The objective of this study was to support the rehabilitation process and ADLs through the development of the Flexible Linkage Hand Exoskeleton Rehabilitation Robot (FLEXOR), a five fingers 3D printed prototype actuated by linear actuators. FLEXOR was controlled using intended movement to support the independent exercises and to assist the ADLs movement. An Arduino-based control system driven by electromyography (EMG) signal was developed for FLEXOR. The new control system protected the hand against over-flexing and excessive application of force. The control system was programmed into three different operating modes which enable FLEXOR to provide passive exercises to the fingers, assist fingers in ADLs movement with minimal efforts, and provide active exercises while assisting fingers in ADLs

Investigation of the Usage of Oil Palm Harvesting Tools on Work Related Musculoskeletal Disorders of Lower Limb

Worker’s health and safety are important for the plantation’s sustainable development. In the oil palm industry, the harvester is exposed to work-related musculoskeletal disorders (WMSDs) during the fresh fruit bunch (FFB) harvesting process. The objective of this study was to investigate the effect of harvesting tools namely chisel, pole, and loading spike towards WMSDs on harvester’s lower limb. Rapid Upper Limb Analysis (RULA) in the CATIA and Human Musculoskeletal Model Analysis (HMMA) in the AnyBody software was applied to model and simulate the harvester’s movement during the harvesting process. The RULA simulation results indicated that the harvester’s lower limbs were exposed to WMSDs where further investigation and changes were required immediately. HMMA results indicated that the Gastrocnemius Medialis muscle had the highest mean muscle force. This study is important as an early ergonomics intervention for occupational health

Experimental Analysis of Ankle Foot Orthosis Using Pneumatic Artificial Muscle

Ankle Foot Orthosis (AFO) is a rehabilitation device which is used to assist patients with weakness over the ankle, foot and part of the leg especially when surgery is not warranted or during the recovery phase of the foot. In this research, the Pneumatic Artificial Muscle was used to develop and actuate the AFO to mimic the movement of the ankle, namely, plantarflexion, dorsiflexion and eversion. Gait pattern analysis was used to gauge the effectiveness of the AFO in human subjects. Two healthy subjects were recruited to simulate gait patterns. The gait analysis showed that the AFO actuated PAM was able to resist plantarflexion while assisting dorsiflexion. During the stance phase, the AFO were able to allow free ankle movement up to approximately 5° dorsiflexion. It also allowed approximately 9° eversion of the ankle from neutral position. Toe drag in the swing phase was avoided as the foot drop was prevented. In conclusion, the AFO performed well in providing support for a foot drop condition and this presents an opportunity for further testing in real patients with foot drop

Development of Batch Type Convection Dryer for Fish Cracker Manufacturing

Manual production of fish cracker is inherenly inefficient with low productivity. Mechanisation and automation of the drying process which constitutes a major process would contribute to increase production. In this study, a batch type convection dryer for fish cracker with a capacity of 2 kg was developed. The prototype with a dimension of 89-cm length, 72-cm width and 60-cm height consists of a drying chamber, moving tray, transmission system, heating element and control system. A moving tray concept was applied for the machine design. The maximum temperature that can be reached in the chamber without load is 40.0 °C. Two different air velocities of 1.5 m/s and 2.0 m/s were applied in both simulation and experimental study. The higher air velocity was observed to shorten the time taken to heat the overall drying chamber. It was observed that the air velocity is higher when the tray rotates close to the fan inlet at the angle of 135°. The simulation results are consistent with the experiment in terms of temperature profile and air velocity. As a result, the dryer has successfully improved the drying hygiene and maintain the quality of fish cracker produced

Mechanism of early-summer low-temperature extremes in Japan projected by a nonhydrostatic regional climate model

We investigated the mechanisms associated with projected early-summer low-temperature extremes in Japan at the end of the 21st century by means of a well-developed nonhydrostatic regional climate model under the A1B scenario provided by the Intergovernmental Panel on Climate Change-Special Report on Emission Scenario. The projected surface air temperature reveals that even in a climate warmer than that at present, extremely low daily minimum temperatures in early summer are comparable to those in the present climate at several locations. At locations where future low temperatures are remarkable, the temperature drop at night is larger in the future than at present. This temperature drop results from mainly two heat fluxes: upward longwave radiation and latent heat flux. In the future climate, upward longwave radiation increases owing to high temperature at the surface around the time of the sunset. In addition, the upward flux of latent heat increases owing to low relative humidity just above the surface. These dryer conditions are associated with lower relative humidity at 850 hPa, suggesting the effects of synoptic systems. These two fluxes act to reduce the surface temperature, and hence surface air temperature

Preliminary Study on Muscle Force Estimation using Musculoskeletal Model for Upper Limb Rehabilitation with Assistive Device for Home Setting

Post-stroke rehabilitation using assistive device has the potential to cover the need for improvement of the upper limb functionality. Moreover, using a biomechanical model to estimate the muscle activity during the rehabilitation training could improve the training module as well as help understand the target muscle during the motion of body part while using the assistive device. In this study, the author has focused on using a musculoskeletal model of the right arm to estimate the individual muscle force by simulating the movement of the right arm while using the developed assistive device. A developed upper limb assistive device has been investigated for its potential as a rehabilitation device for persons with physical disability of upper limb motion. The muscle force estimation is based on an inverse dynamic method, improved with additional constraints of the joints in order to obtain the muscle’s activity from motion capture data. The acquired muscle force data could be used to improve the arm assistive device in rehabilitation training for home setting purpose

Ergonomics Simulation and Analysis of Specially Designed Chair

Chair comes in different sizes and shapes depending on the functions as well as the users involved. However, the designers seldom consider the ergonomics aspect in chair design. This research has been conducted as a case study to compare and select the best design parameters within two chairs known as Chair A and B using human modelling software called AnyBody. Different parameter was manipulated in the simulation which is backrest angles for Chair A and seat heights for Chair B. A total of ten chairs with different parameters (five from Chair A and five from Chair B) were conducted in the simulation. Results were generated through inverse dynamics analysis in the form of muscle activities envelopes and reaction force on vertebrae L4 to L5. The result shows that 80° backrest was the best ergonomics design for Chair A while 0.30 m seat height was the best ergonomics design for Chair B. The simulation conducted is important as an early ergonomics intervention before the real chair fabrication is conducted

A Method to Analyze Dynamics Properties of Transfemoral Prosthesis

Abstract.The methodto compute gait cycle forces and moments acting on the hip and knee joints of a lower limb with a trans-femoral prosthesis were investigated. A 3D model of the lower limb with prosthesis was created using CAD software and based on MRI data and real size dimension. The transfemoral prosthesis was modelled as a coupled of links with two revolution joints at hip and knee joint. This coupled link was connected to a bar with translation joint to description the distance walked of people in gait cycle. All parts of the prosthesis were measured and a full-size 3D model was created.The kinematics parameters of a lower limb with a prosthesis were determined from motion-captured system data. The reaction force was measured with a force sensor in the footplate. The 3D model of the prosthesis was exported to MatlabSimmechanics. The input data which are kinematic parameters were applied to calculate the forces and moments acting on the joints. The results of this study present a method to analyse the dynamic properties of transfemoral prosthesis including speed of the gait. It could be used to calculate the load transferred from the socket to the residual limb. They could also be used to design the structure of a prosthesis and optimize the dynamic characteristics of such a prosthesis