420 research outputs found
Dynamically Optimized Muscle Activity Patterns From A Novel Handle Based Propulsion Movement For A Wheelchair
No full textThe purpose of this study was to determine the muscle activity patterns resulting from dynamic optimization of a novel continuous wheelchair propulsion movement having a circularity ratio of 0.89.
For the study four major muscle groups were selected and a bang-bang control strategy was adopted to reduce the complexity and time for the optimization with a cost function to increase the net propulsion power. The successful completion of the optimization resulted in muscle excitation and activation curves for each actuator and a net power > 30 watts. The proposed propulsion mechanism can act as a substitute for the normal propulsion mechanisms used in daily life and sports activitie
A Test Rig for Investigating Manual Wheelchair Propulsion Devices
No full textThe developed wheelchair based test rig allows analysing and comparing alternate hand driven mechanisms for wheelchair propulsion including propulsion efficiency as well as loads on the musculoskeletal structure. A controlled brushless motor combined with a fly wheel mounted on a normal wheelchair is used to simulate the acceleration and deceleration phases as well as the resistance power. Propelling the wheelchair by using the push rim or an attached front drive, the motor generates a resistance torque that is transmitted via timing belts to the push rim wheels and front drive pulleys. A motor integrated hall sensor is used to control the motor as well as to provide important speed information for the software. First tests on healthy subjects have shown that the test rig provides conditions very close to reality and both the various mounting possibilities for hand propelling devices as well as its connectivity have been proved useful
»Så skärper den ena människan den andra» : Om litteraturkritikern Margit Abenius och hennes många nätverk
No full textAn essay on the life and work of the Swedish literary critic Margit Abenius (1899-1970) and on her various social networks. The essay focuses on Margit Abenius' life-long depression and on its impact on her professional career. The aim is to study whether, and in what way, Abenius handled her desease and how she managed to make it a resource in her work as a literary critic and author. The essay is a part of Marta Ronne's research project on Margit Abenius and the Swedish literary critique 1930-1970 (book in progress).</p
INFLUENCE OF WALKING SPEED ON THE ANGLES OF THE FOOT IN HEALTHY ADULTS USING THE OXFORD FOOT MODEL Karoline Seibert (1), Margit Gföhler (1), Andreas Kranzl (2) 1. Technical University Vienna, Austria; 2. Laboratory for Gait and Human Motion Analysis of the Orthopaedic Hospital Speising, Austria; Introduction Data
No full textZusammenhang zwischen Massenschwerpunkt und Angriffspunkt der resultierenden Bodenreaktionskraft beim Gehen im medizinischen Kontext
Get PDFModular arm orthosis with weight support: mechanical concept
No full textModular Arm Orthosis with Weight Support: Mechanical Concept
Reichenfelser W, Karner J, Gföhler M
Vienna University of Technology, Vienna, Austria
Introduction
Passive arm orthoses like the JAECO WREX [1] or the ARMON device [2] support patients with motor impairments in the upper limb when performing activities of daily living.
The presented modular arm orthosis is part of the European MUNDUS (MUltimodal Neuroprosthesis for Daily Upper limb Support) project that aims to assist patients with degenerative neuronal diseases or high level Spinal Cord Injuries (SCI). When clinically applied, it will be combined with Neuromuscular Electrical Stimulation (NMES) to enable the desired arm movements.
Materials and Methods
Representative motions associated with daily living were analyzed and the required ranges of motion estimated. Inverse dynamic simulations were performed in OpenSim [3] to determine the external joint torques. The characteristic of the weight support was calculated with Matlab and the resulting mechanical 3D design was done in Catia V5R19, focusing on modularity, simplicity and low weight.
Results
The outcome of the preliminary investigations is an orthosis design with two degrees of freedom (DoF) at the shoulder, one at the elbow joint and one for pro- and supination. These DoF can be locked with electromagnetic brakes to support the control of the NMES induced arm movement. The weight supporting spring is integrated in a tube that is attached to a harness for mobile use or mountable to a wheelchair. The compensating force of the spring is transferred via a rope to the upper arm shell. The orthosis is also prepared to carry a hand module that can activate the fingers. Depending on the severity or progression of the disease motors can be added to the DoF that can not be actuated by NMES sufficiently.
Discussion and Conclusion
The mechanical concept offers a both-sided, modular system which is assembled with regard to the severity of the motor impairment. It can be worn by the patient or attached to a wheelchair. Additionally to the provided weight support each DoF can be locked at defined positions what should ease the control of the arm motion when actuated by NMES. In a subsequent study the functionality of the prototype will be evaluated with patients at the rehabilitation centre.
Acknowledgment
This work is part of the European Project MUNDUS, funded by the call EC FP7 ICT 2009-4.
References
[1] http://jaecoorthopedic.com; cited April 28, 2011
[2] Herder J, et al., JRRD 43, 5, 591-604, 2006.
[3] Delp SL et al., IEEE Trans Biomed Eng, 54, 11, 1940-50, 2007
Novel handle based propulsion mechanism for wheelchair: : Using forward dynamic optimization and kinematic-kinetic analysis
No full textThe Effects of passive path spring implementation parallel to weakened M. rectus femoris during walking: an openSim simulation study
Get PDFMuscle weakness can cause devastating impacts on the gait pattern. Thus, research on devices and elements, capable to assist walking movement is of high importance. This thesis intends to investigate the effects of passive path spring implementation parallel to m. recuts femoris for persons suffering from m. rectus femoris weakness. The study is limited to the pre-swing, initial and mid-swing phases of gait and focusses on the three muscles m. rectus femoris, m. vastus intermedius and m. biceps femoris caput longum. Five main muscle parameters are selected for investigation: force, power, normalized fiber length, normalized fiber velocity and induced femur acceleration. Results show that the spring exhibits a positive effect on force and power of m. vastus intermedius but shows a comparable negative effect in force and power of m. biceps femoris caput longum. Furthermore, the spring affects the induced femur accelerations of all considered muscles in a negative way. The study is performed using the simulation software OpenSi
- …
