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No description available.

The work in this thesis was concerned with the safety evaluation of a fully powered mechanical patient lift for bariatric patients. A working prototype of this system, called RoboNurse, was designed and manufactured at iDAPT technology team at Toronto Rehabilitation Institute. There are currently no lifting technologies similar to RoboNurse in the healthcare industry. The methods that are used to evaluate the system included: 1) Series of mechanical tests to evaluate the static strength and stability of the design 2) Computer simulations to evaluate the dynamic stability of the system and 3) Failure mode and Effects Analysis (FMEA) and Fault Tree Analysis (FTA) as risk analysis tools. These techniques helped to perform thorough and systematic evaluations on the system and its components. This study significantly assisted in understanding the problems associated with the current design prototype and provided the necessary resources and guidelines for the future generations of this technology.

The work in this thesis was concerned with the safety evaluation of a fully powered mechanical patient lift for bariatric patients. A working prototype of this system, called RoboNurse, was designed and manufactured at iDAPT technology team at Toronto Rehabilitation Institute. There are currently no lifting technologies similar to RoboNurse in the healthcare industry. The methods that are used to evaluate the system included: 1) Series of mechanical tests to evaluate the static strength and stability of the design 2) Computer simulations to evaluate the dynamic stability of the system and 3) Failure mode and Effects Analysis (FMEA) and Fault Tree Analysis (FTA) as risk analysis tools. These techniques helped to perform thorough and systematic evaluations on the system and its components. This study significantly assisted in understanding the problems associated with the current design prototype and provided the necessary resources and guidelines for the future generations of this technology.

A hybrid bearing designed for use in a next generation turbo-pump is evaluated for the performance of initial lift-off, referred to as start-transient. The radial test rig features a high-speed spindle motor capable of 20,000 rpm that drives a 718 Inconel rotor attached via a high-speed coupling. The drive end is supported by ceramic ball bearings, while the hybrid bearing supports the opposite end. A magnetic bearing delivers the applied loading along the mid-span of the rotor. Many parameters, including ramp rate [rpm/s] (drive torque), supply pressure at 15,000 rpm, magnitude of the applied load, and load orientation, are varied to simulate different start-transient scenarios. The data are recorded in .dat files for future evaluation of transient predictions. Analysis of the data includes an evaluation of hydrodynamic and hydrostatic liftoff, an assessment of rub from passing through a lightly damped critical speed, and observation of pneumatic hammer instability. Hydrodynamic lift-off occurs when the hydrodynamic pressure, resulting from the relative motion of two surfaces, overcomes the forces acting on the rotor; no indication of hydrodynamic lift-off is provided. Hydrostatic lift-off results from the external supply pressure (which for this test rig is speed dependent) overcoming the forces acting on the rotor as determined from rotor centerline plots. With 0.263 bar applied unit load in the vertical direction, hydrostatic lift-off occurs at 0 rpm and 2.08 bar supply pressure. With a much higher load of 1.53 bar, hydrostatic lift-off is at 12,337 rpm and 10.7 bar supply pressure. The required supply pressure for hydrostatic lift-off is approximately a linear function of the applied unit load. In a turbopump, hydrostatic lift-off depends on the speed because the supply pressure is proportional to the speed squared. With the load in the horizontal direction, hydrostatic lift-off occurs at lower speeds and pressures. The ramp rate did not affect the required supply pressure for hydrostatic lift-off. A lower supply pressure at 15,000 rpm lowered the required supply pressure for hydrostatic liftoff as well as the natural frequencies creating a rub. The hydrostatic lift-off speed should be minimized to avoid damage to the rotor/bearing surfaces due to contact.

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Thesis (Ph. D.)--Worcester Polytechnic Institute. / Keywords: Vortex; unsteady flow; circulation; three-dimensional flow; aerodynamics; instantaneous lift. Includes bibliographical references (p. 182-188).

Thesis (M.S.)--Worcester Polytechnic Institute. / Keywords: Low Reynolds Number; Micro Air Vehicle; Low Aspect Ratio; Spanwise pressure measurements; Spanwise Lift Distributions. Includes bibliographical references (p. 84-85).

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