Type of Document	Master's Thesis
Author	Patrangenaru, Vlad Petru
URN	etd-01112006-160352
Title	DEVELOPMENT OF DYNAMIC SEATING SYSTEM FOR HIGH-TONE EXTENSOR THRUST
Degree	Master of Science
Department	Mechanical Engineering
Advisory Committee	Advisor Name Title Singhose, William Committee Chair Sanborn, David Committee Member Sprigle, Stephen Committee Member
Keywords	dynamic seating inverse dynamics extensor thrust wheelchair design
Date of Defense	2006-01-05
Availability	unrestricted
Abstract High-tone extensor thrusts, or involuntary muscle contractions experienced by many children with cerebral palsy, can cause problems that are not addressed by current seating systems. This thesis is concerned with the development of a dynamic seating system to better accommodate individuals who exhibit high-tone extensor thrusts. The first part of the thesis is focused on obtaining a general understanding of extensor thrusts from a mechanical perspective. To achieve this goal, an analytical dynamic model of a human subject undergoing an extensor thrust on a rigid chair is created. This model is validated experimentally, and inferences about the nature of extensor thrusts are made from the simulation and experimental results. A Dynamic-Hingeback Seating System which allows the occupant to lean back during an uncontrolled extensor thrust is developed. This system is capable of maintaining seatback rigidity during an intentionally-induced episode, thereby enabling the occupant to communicate or interact with his/her environment. The design of this system is influenced by the results obtained from the rigid seat study, as well as by numerical simulation results gathered with a commercial dynamic simulation software package (Working Model 2D). The improved seatback performance is characterized through experimentation. Alternative dynamic seating systems are considered. The important features of each of these systems are identified, and the desired motion of the system occupant during an extensor thrust is verified through Working Model simulations.
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