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.
An efficient three-dimensional (3-D) routing technique is presented for multilayer ceramic printed circuit (PC) boards. The router can take account of via length as well as pattern length. In the first of the two steps involved, it searches in the direction of via depth from start and end points only. This is called two-and-a-half-dimension (2.5-D) routing. Step two combines 2-D and 3-D routing for wiring not covered in step one. This enables tens of thousands of wires to be routed at 99% effectiveness in less than four hours of CPU time, with all delay conditions satisfied.< >
In Japan, the number of total knee arthroplasties (TKA) has been increasing as the society is progressively aging. TKA is an operation consisting in removing the damaged surface of a patient's knee joint and implanting an artificial one. The implantation angle of the artificial knee joint depends on the mechanical axis crossing the hip joint of the patient. However, it's difficult for medical doctors to accurately visualize a patient's mechanical axis in a clinical setting during the operation. Because the existing systems that can estimate the mechanical axis present several disadvantages such as cost, size, and complexity, they have not been widely used. The aim of this research is to develop a simple and low cost system to estimate a patient's mechanical axis in a clinical setting. A three-axis inertial measurement unit (IMU) is attached to the bone cutting guide. When the femur is swung, either horizontally or vertically, the angular difference in roll, pitch and yaw is proportional to the angular difference between the mechanical and sensor's axis. From this, the angular difference between mechanical and sensor's axis can be calculated. In our experiments, the angular differences were 0°, ±5.0°, ±10.0°, and ±15.0°, with calculated angle errors below 1.0°. These results indicate the effectiveness of our system for application in TKA.
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.
In this study, a system for evaluating the wheelchair seating posture is introduced. The system consists of three subsystems: a seating posture changing system, a seating posture analysis system, and a propulsion analysis system. The seating posture changing system uses pneumatically controlled airbags installed in the wheelchair seat to change the posture of the patient and aims to generate a good posture heuristically. The seating posture analysis system uses seat sensors, video cameras, and whose analysis software to measure and analyze the current posture by seat sensors. One of the features of the analysis system is that the shape of the spine is estimated virtually, as the shape is one of the best indicators of a patient's posture. From the current seating posture, the propulsion analysis system estimates the posture, driving force, and muscular forces necessary to propel the wheelchair. Basic hardware and software for the pneumatically controlled functions have been developed for the posture changing system, and the displacements of the human body were measured by a 3D motion analysis system when four airbags were filled with air independently. A method to estimate the spinal shape by the finite element method (FEM) using beam elements has been developed for the seating posture analysis system. This method has a fast processing time and takes external forces into consideration. A method that can estimate the position of the neutral axis of the spine from markers placed on body surfaces was also developed. For the propulsion analysis system, propulsion motion and muscular forces of a subject in the wheelchair with a seat cushion or a back seat cushion were analyzed. Future work includes the development of the remaining functions, such as the overlay display function of the video camera images and sensor data, and the integration of the entire system.
Checking the fit between a prosthetic socket and a residual limb is important for functional prostheses. Designing a prosthetic socket using a CAD system and checking the above mentioned fit by analyzing the deformation and stress under the weight of an amputee requires a three-dimensional model of the residual limb that includes not only the surface, but also the fat, muscle and bone. An ultrasonic measurement system, including a probe that three-dimensionally measures the external surface shape and the shapes of internal tissues simultaneously was developed. The system uses wavelet analysis to define the positions of the boundaries between each tissue. A cone-shaped aluminum test object was measured using the system, which was shown to be capable of measuring radius with an error of 0.6mm and slope with an error of 6%. In addition, the lower legs were measured, and the surface, muscles and bone boundaries were defined by wavelet analysis. The results of these measurements were compared to MRI cross sectional data, and the average error for the leg surface, muscles and tibia were 1.7mm, 2.4mm and 1.9mm, respectively, for boundaries that were determined correctly.
Project-based learning (PBL) is effective for developing human resources of young students. The design of welfare equipment, such as wheelchairs and gait assistive devices, is taken as the subject in this study because these devices must be fit to their environment, users, and method of use; students must consider the circumstances of each country concerned. The program commenced in 2012 at L'Aquila, Italy, and the Shibaura Institute of Technology, Japan and has been continuing for three years. Students were divided into four groups and discussions were held on how to adapt the equipment to the user and environment. After discussion, they designed and simulated a model of the equipment using CAD. Finally, they presented their designs to each other. Through the program, students had fruitful discussions, exchanged ideas from different cultures, and learned from each other. Furthermore, friendships among the students were nurtured. It is believed that the objective of the program was satisfactorily accomplished.
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