Thesis (Ph. D.)--University of Wisconsin--Madison, 1964. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (M.App.Sc.) - Carleton University, 2007. / Includes bibliographical references (p. 108-112). Also available in electronic format on the Internet.

All vehicles have changing payloads that affect their dynamic response. Compared to passenger vehicles, heavy machinery have larger and more greatly varying payload masses, higher centers of mass, and encounter larger disturbances. These factors lead to significant increases in the amount of vibration experienced by heavy machinery operators. This fact, when coupled with the large amount of exposure time that a typical heavy machinery operator incurs, leads to much greater vibration dosage values for the heavy machinery operator. In addition, the heavy machinery operator faces equal or greater opportunity for accident. The chance of accident, along with the increased vibration dosage, leads to an operating condition with significant safety risks, both short and long term. It has been shown that payloads affect both the stability and vibration isolation properties of a vehicle. Large payloads reduce vehicle stability while increasing the amount of vibration transmitted to the operator. A method to compensate for these loading affects would prove to be a useful technique to increase the safety of the vehicle, both in terms of accident avoidance and long term health effects of vibration. This thesis provides such payload compensation techniques. Improved vehicle dynamics were accomplished with the use of both active and semi-active suspension control. The active systems used are optimal control based, and provided the greatest improvements in vehicle performance. An optimal controller designed around a nominal payload, however, proved insufficient for operation over the entire payload range due to too large peak actuator forces at low payloads. A multiple model approach was used to remedy this problem. Semi-active systems based on a Linear Quadratic Regulator with output feedback and damping selection via static deflection were developed. The semi-active systems would require far less power than the active systems, with the need for knowledge of fewer systems states. It was shown that despite these lower demands, the semi-active systems closely approach the performance of the fully active systems.

<p>The use of drones, also called unmanned aerial vehicles (UAVs), is increasing every day. These aircraft are piloted either remotely by a human pilot or completely autonomously by an on-board computer. UAVs are typically equipped with a video camera providing a live video feed to the operator. While they were originally developed mainly for military purposes, many civil applications start to emerge as they become more affordable.<p><p><p>Micro air vehicles are a subgroup of UAVs with a size and weight limitation; many are designed also for indoor use. Designs with rotary wings are generally preferred over fixed wings as they can take off vertically and operate at low speeds or even hover. At small scales, designs with flapping wings are being explored to try to mimic the exceptional flight capabilities of birds and insects. <p><p><p>The objective of this thesis is to develop a control mechanism for a robotic hummingbird, a bio-inspired tail-less hovering flapping wing MAV. The mechanism should generate moments necessary for flight stabilization and steering by an independent control of flapping motion of each wing.<p><p><p>The theoretical part of this work uses a quasi-steady modelling approach to approximate the flapping wing aerodynamics. The model is linearised and further reduced to study the flight stability near hovering, identify the wing motion parameters suitable for control and finally design a flight controller. Validity of this approach is demonstrated by simulations with the original, non-linear mathematical model.<p><p><p>A robotic hummingbird prototype is developed in the second, practical part. Details are given on the flapping linkage mechanism and wing design, together with tests performed on a custom built force balance and with a high speed camera. Finally, two possible control mechanisms are proposed: the first one is based on wing twist modulation via wing root bars flexing; the second modulates the flapping amplitude and offset via flapping mechanism joint displacements. The performance of the control mechanism prototypes is demonstrated experimentally. / Doctorat en Sciences de l'ingénieur / info:eu-repo/semantics/nonPublished