Invasive weed optimization algorithm optimized fuzzy logic scaling parameters in controlling a lower limb exoskeleton

© 2016 IEEE. This paper describes a new modified versions of invasive weed optimization algorithm with exponential seeds-spread factor. The modified invasive weed optimization algorithm (MIWO) is employed to optimize the fuzzy input-output scaling factors of lower limb exoskeleton. A fuzzy logic control (FLC) system with the (MIWO) are evolved for reference tracking control. The exoskeleton is developed to enhance and upgrade the lower limb capability and augment the torque of knee and hip of elderly people during the walking cycle. Invasive weed optimization is a bio-inspired search algorithm that mimics how weeds colonize a certain area in nature. The algorithm is modified by applying local knowledge during distribution of seeds that depends on their cost function value in each generation to narrow the accuracy and improve the local search ability. The obtained results from the modified invasive weed optimization algorithm are compared with heuristic gain values to improve the performance of the exoskeleton system. The Visual Nastran 4D software is used to develop a simulation model of the humanoid and an exoskeleton for testing and verification of the developed control mechanism. Simulation results demonstrating the performance of the adopted approach are presented and discussed

Modelling and simulation of double-link scenario in a two-wheeled wheelchair

Wheelchairs on two wheels are essential part of life for disabled persons. But designing control strategies for these wheelchairs is a challenging task due to the fact that they are highly nonlinear and unstable systems. The subtle design of the system mimics the inverted pendulum with a double-link scenario. This forms an example of multi degree of freedom system where there are three actuators, one on each wheel, and one for position between the two links. The system starts to work with lifting the front wheels (casters) to the upright position and further on stabilizing in the upright position. The challenge resides in the design, modelling and control of the two-wheeled wheelchair to perform comparably similar to normal four-wheeled wheelchair. This paper is aimed to model the highly nonlinear and complex two-wheeled wheelchair system using two different approaches. A state-space model is obtained from the linearised mathematical model as an initial attempt for control design investigation. Then a complex visualized mathematical model is developed, which proves as a good technique for prediction and simulation of the two-wheeled wheelchair

Viscoelastic finite element analysis of the cervical intervertebral discs in conjunction with a multi-body dynamic model of the human head and neck

This article presents the effects of the frontal and rear-end impact loadings on the cervical spine components by using a multi-body dynamic model of the head and neck, and a viscoelastic finite element (FE) model of the six cervical intervertebral discs. A three-dimensional multi-body model of the human head and neck is used to simulate 15g frontal and 8.5g rear-end impacts. The load history at each intervertebral joint from the predictions of the multi-body model is used as dynamic loading boundary conditions for the FE model of the intervertebral discs. The results from the multi-body model simulations, such as the intervertebral disc loadings in the form of compressive, tensile, and shear forces and moments, and from the FE analysis such as the von Mises stresses in the intervertebral discs are analysed. This study shows that the proposed approach that uses dynamic loading conditions from the multi-body model as input to the FE model has the potential to investigate the kinetics and the kinematics of the cervical spine and its components together with the biomechanical response of the intervertebral discs under the complex dynamic loading history

The Register, 2001-11-12

https://digital.library.ncat.edu/atregister/2253/thumbnail.jp

NASA Tech Briefs, January 2001

The topics include: 1) A "Model" of Interactive Engineering; 2) Feature Section: Communications Technology; 3) lnReview; 4) Application Briefs; 5) Submillimeter-Wave Image Sensor; 6) Ultrasonic/Sonic Drill/Corers With Integrated Sensors; 7) Normally Closed, Piezoelectrically Actuated Microvalve; 8) Magnetostrictively Actuated Valves for Cryosurgical Probes; 9) Remote Sensing of Electric Fields in Clouds; 10) Wireless-Communication Headset Subsystem To Enhance Signaling; 11) Power Amplifier With 9 to 13 dB of Gain From 65 to 146 GHz; 12) Humidity Interlock for Protecting a Cooled Laser Crystal; 13) A Lightweight Ambulatory Physiological Monitoring System; 14) Improvements in a Lightning-Measuring Instrument; 15) Broad-Band, Noninvasive Radio-Frequency Current Probe; 16) Web-Based Technology Distributes Lean Models; 17) Software Guides Aeroelastic-Systems Design; and 18) Postprocessing Software for Micromechanics Analysis Code. A Photonics West 2001 Preview Tech Brief supplement to this January 2001 issue is also included

An investigation into spinal injury from vehicle crashes in Saudi Arabia

The primary purpose of this thesis is to present a comprehensive analysis of occupant kinematics and spinal injuries, during road traffic accidents in Saudi Arabia from the points of view of statistical analysis, modeling of occupant kinematics, and biomechanics. An in-depth database containing information on 512 real world vehicle crashes was constructed. The study identifies the characteristics of the collisions and occupant spinal injuries in Saudi Arabia, and suggests measures to mitigate them. A logistic model has been presented which can be used to provide information about the crashes and spinal injuries. The model may serve as an initial prediction to establish the risk of spinal injury sustained by occupants at road crash, and a paramedic’s protocol, as part of the emergency response, could be revised according to the developed model. State of the art techniques for accident reconstruction have been demonstrated as a tool to investigate the crashes, and the probable cause of crashes, and to make recommendations to prevent crashes and/or mitigate the severity of the accidents and resulting spinal injuries. Computational simulations of crashes provide a tool for understanding the dynamics of crashes and injuries, and are being used worldwide to study dynamics of crashes and efficacy of safety devices. The work conducted here has demonstrated how crashes can be simulated to estimate the injury parameters, and the likelihood of injuries on various parts of the body. While this study presents a detailed multi-dimensional study on road traffic crashes and spinal cord injuries therein, it remains a pilot study for Saudi Arabia. It demonstrates how this type of study can have far reaching consequences and the need to collect such data and carry out this kind of a study on a regular basis at the national level.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

NASA Tech Briefs, April 2002

The contents include: 1) Application Briefs; 2) Sneak Preview of Sensors Expo; 3) The Complexity of the Diagnosis Problem; 4) Design Concepts for the ISS TransHab Module; 5) Characteristics of Supercritical Transitional Mixing Layers; 6) Electrometer for Triboelectric Evaluation of Materials; 7) Infrared CO2 Sensor With Built-In Calibration Chambers; 8) Solid-State Potentiometric CO Sensor; 9) Planetary Rover Absolute Heading Detection Using a Sun Sensor; 10) Concept for Utilizing Full Areas of STJ Photodetector Arrays; 11) Development of Cognitive Sensors; 12) Enabling Higher-Voltage Operation of SOl CMOS Transistors; 13) Estimating Antenna-Pointing Errors From Beam Squints; 14) Advanced-Fatigue-Crack-Growth and Fracture- Mechanics Program; 15) Software for Sequencing Spacecraft Actions; 16) Program Distributes and Tracks Organizational Memoranda; 16) Flat Membrane Device for Dehumidification of Air; 17) Inverted Hindle Mount Reduces Sag of a Large, Precise Mirror; 18) Heart-Pump-Outlet/Cannula Coupling; 19) Externally Triggered Microcapsules Release Drugs In Situ; 20) Combinatorial Drug Design Augmented by Information Theory; 21) Multiple-Path-Length Optical Absorbance Cell; 22) Model of a Fluidized Bed Containing a Mixture of Particles; 23) Refractive Secondary Concentrators for Solar Thermal Systems; 24) Cold Flow Calorimeter; 25) Methodology for Tracking Hazards and Predicting Failures; 26) Estimating Heterodyne-Interferometer Polarization Leakage; 27) An Efficient Algorithm for Propagation of Temporal- Constraint Networks; 28) Software for Continuous Replanning During Execution; 29) Surface-Launched Explorers for Reconnaissance/Scouting; 30) Firmware for a Small Motion-Control Processor; 31) Gear Bearings and Gear-Bearing Transmissions; and 32) Linear Dynamometer With Variable Stroke and Frequency

NASA Tech Briefs, November 2001

Topics include: special coverage section on data acquisition, and sections on electronic components and systems, software, materials, machinery/automation, physical sciences, book and reports, and a special section of Photonics Tech Briefs

NASA Tech Briefs, September 2001

Topics include: special coverage section on sensors, and sections on electronic components systems, software, materials, machinery/automation, manufacturing/fabrication, bio-medical, book and reports, and a special section of Photonics Tech Briefs