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The purpose of this study was to determine the effects of back and seat rest inclination on the kinematics of manual hand-rim wheelchair propulsion in subjects with spastic type cerebral palsy. Subjects ranged in age from nine to twenty-one and were classified as USCPAA Class III or IV functional ability. Subjects were required to propel a standardized wheelchair at six seat positions from combinations of back rest angles of 0, 3 and -5 degrees from vertical and thigh angles of 0 and 5 degrees from horizontal. Combinations of thigh/seat rest angles were 0/-5, 5/-5, 5/0, 5/3, 0/3, 0/0 constituting the six different conditions. Subjects were filmed while wheeling in each seat position. Wheeling was performed at two and three kilometers per hour on a low friction roller system. It was hypothesized that since individuals with spastic type cerebral palsy have improved functional upper extremity performance as the body center of mass is positioned over the ischial tuberocities and hip flexion angle is maintained at 90 degrees (0/0), that similar results would be found in wheelchair propulsion. Based on the results of kinematic data analyzed in this study there was no indication that the 0/0 seat position was superior for subjects with cerebral palsy under the conditions of this study. Larger elbow flexion/extension range of motion (p = .06) exhibited by the 5/3 and 5/0 seat orientations suggests that these positions provide a more effective wheelchair propulsion orientation for subjects in this study. / Graduation date: 1996

D. Tech. Electrical Engineering. / Developes a wheelchair motion platform whereby its user may be introduced into a simulated world. This simulated world is then required to be closely related to real world spaces that will be encountered by a disabled person using a wheelchair as a mobility aid. The wheelchair to be accommodated in the simulation environment may have multiple mechanical construct possibilities. The wheelchair used on the simulation platform needs to be driven by a combination of two wheels, as is generally found on manual and electric wheelchairs. The final objective was to design the simulation as closely as possible to the real world in order to use the VS-1 motion platform for architectural evaluations, possible training and general research in the field of simulators used in an enabled environment.

People with severe trunk impairments cannot maintain or control upright posture during sitting or reaching out with the upper body. Passive orthoses are clinically available to support the trunk and promote the use of upper extremities in this population. However, these orthoses only rigidly position the torso on a wheelchair but do not facilitate movement of the trunk. In this dissertation, we introduce a novel active-assistive torso brace system for upperbody movements by a subject while seated. We have named this system as Wheelchair Robot for Active Postural Support (WRAPS). We propose designs of two robots, one for the pelvis and the other for the trunk. Each of the two devices has a parallel chain architecture to accommodate the range of motion (ROM), respectively for the pelvic and thoracic segments. The first thoracic robot was designed for the upper trunk motion relative to the pelvis. It has a 2[RP]S-2UPS architecture which provides four degrees-of-freedom (DOFs) to the end-effector placed on the upper trunk. The second is a pelvic robot which is designed to orient the pelvic segment relative to the seat. It has a 3-DOF [RRR]U-2[RR]S architecture, coupled with translation to accommodate pelvic movements relative to the seat. These robot architectures are synthesized based on human movement data. WRAPS can modulate the displacement of both the pelvic and the thoracic segments. Additionally, the forces can be applied on the torso through the end-effectors of these robots. Each of the robot prototypes was evaluated with able-bodied subjects to assess the device wearability, kinematic performances, and control system.

M. Tech. Electrical Engineering. / Discusses how to develop the kinematic and dynamic model and the controller for the 2-DOf motion platform used in an augmented reality environment for wheelchair driving. This comes as a motivation to help to train disabled and elderly people to drive wheelchairs.. With accurate inverse dynamic model, it is possible to achieve high performance control algorithms of robots and direct dynamic model is required for their simulation. The other part of this research was to model and control the roller for the feedback of the wheelchair wheels.

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.