Slider-crank mechanisms are widely used in reciprocating machinery, where transformation from rotational into translational motion (or vice versa) is required. Moreover, the use of these mechanisms is quite common in robotic and mechatronic systems when complex motions are to be produced with rotational actuators. However, the velocity ratio of the slider-crank mechanism is configuration-dependent and thus, elaborate algorithms are required to precisely control its performance. / In this thesis, a planar cam mechanism with an oscillating follower is proposed as a device that renders the velocity ratio of the slider-crank mechanism constant, an operation that is termed here velocity-ratio rectification ; it is expected that the rectification will ease the feedback control of the slider-crank mechanism in mechatronic applications. A methodology for the optimization of this mechanism is developed. First, the performance of the slider-crank mechanism is analyzed and optimum geometric parameters are obtained. Then, an expression for the input-output relation of the cam mechanism at hand is derived, and the corresponding displacement program of the follower is produced. In addition, an approach for the optimization of planar cam mechanisms with an oscillating follower is introduced, to minimize the overall size, while maintaining an acceptable force-transmission performance based on bounds on the pressure angle. A Graphical User Interface (GUI) is developed to allow for the above-mentioned optimization in an interactive mode; the GUI is successfully used in an example of the design of a reducer-rectifier cam mechanism that rectifies the velocity ratio of the actuator of a robotic quadruped.

A new type of quadruped robot has been developed, the Scout class. Each leg utilizes only one actuated degree of freedom (as opposed to a typical three) to reduce complexity and cost. The design of the first of these robots, Scout I is presented. In modelling Scout, impacts are assumed instantaneous with angular momentum being conserved about the impacting toe. Stance phases are modelled as a double inverted pendulum with one input and a pin joint with the ground. Walking controllers requiring a minimum of sensing are then developed and examined both in simulation and experiments. Small errors in impact modelling coupled with high setpoint sensitivity are found to result in discrepancies. However, despite this stable open loop walking is achieved in all cases examined. Additional behaviors for Scout are presented, including turning, side stepping, sitting and laying down, and step and stair climbing.

This thesis describes a new Compliant Articulated Robot Leg (CARL) which is a prototype leg for an autonomous quadruped robot. The leg is designed for dynamic walking, trotting and bounding gaits, with an expected top speed of 3m/s. To facilitate the construction of multi-legged creatures, the leg was designed as a modular, self-contained unit with integrated amplifiers and control electronics. It is an articulated 3 DOF design with revolute joints as opposed to prismatic joints for improved mobility, simplicity and low friction. It employs electric actuation instead of hydraulics for indoor power autonomy, improved modeling, control and reliability. The use of fractional horsepower DC motors in a running robot is feasible through a novel AnTagonistic LADD Actuation System (ATLAS) which converts motor effort to high joint torques with similar efficiencies as the best conventional transmissions, but at substantial weight savings.

In this study, the edge effects of composite laminates are investigated mathematically. The presence of stress singularities at the ply interfaces along the free edges is studied. The importance of determining all terms, including interlaminar stresses, in investigating the failure of composite plates is also shown. The simple composite plate, the pin-loaded composite plate, and the bolt-loaded composite plate are analyzed three-dimensionally. / A new "slice" model is developed to simulate the simple composite plate. Three-dimensional finite element analysis is performed with the "slice" model to verify the accuracy of the 20 node isoparametric element. The same stress analysis technique is subsequently performed to study the more complex pin- and bolt-loaded laminate problems. This method determines the entire stress state for each of the three problems. / A failure initiation model is developed and used to predict the failure initiation of the pin- and bolt-loaded composite plates. The model is used to determine the failure initiation modes: Matrix cracking, fiber breakage, and delamination. Experiments are undertaken for comparison with predicted results. Excellent correlation is achieved between predicted results and experimental data. / The effect of geometric parameters is also studied. The investigation provides a method to predict all failure modes by taking into account stress singularities at the free edge, using three-dimensional finite element analysis, and applying a proper failure analysis.

The explosive boiling that occurs when a volatile liquid is suddenly vented to the atmosphere has been investigated experimentally. Refrigerant 22 is used as the test liquid and is depressurized from an initial state of equilibrium using a bursting foil diaphragm. The competition between the rates of venting and vapor generation can lead to substantial repressurization within the vessel. The influence of vent area, quantity of liquid, initial pressure and pre-nucleation on the explosive boiling characteristics has been studied in a 260 ml Teflon-coated vessel as well as in a 75 ml glass tube. The amount of repressurization is found to be proportional to the pressure drop which determines the degree of superheat attained by the liquid. The time for repressurization is typically an order of magnitude larger than the time for the pressure drop. The repressurization in both vessels reaches a maximum value at an initial saturation vapor pressure of $ approx$2 MPa. The dependence of the repressurization on initial pressure observed experimentally is found to be consistent with the predictions of a semi-empirical correlation based on homogeneous nucleation theory. High-speed photography shows that the mode of boiling is dependent on the initial vapor pressure and the surface condition of the vessel walls. Heterogeneous boiling from the walls dominates in the Teflon-coated steel vessel. For initial vapor pressures less than $ approx$1 MPa, an evaporation wave propagates at $ approx$0.15 m/s from the free surface throughout the length of the glass tube. For higher initial vapor pressures the boiling mode in the glass tube becomes predominantly heterogeneous. Pre-nucleation with CO$ sb2$ within the refrigerant increases the boiling response by promoting heterogeneous boiling.

This thesis is a step towards the model-based control of two redundant robots. In the first part of the thesis, a method is presented for autonomous kinematic calibration of a 3-DOF redundant parallel robot. Multiple closed loops are used in a least squares optimization method. Some numerical methods such as column scaling of the gradient matrix and observability indices for the best pose set of robot calibration configurations are discussed. Four observability indices are considered analytically, geometrically, and experimentally. Two of these indices are presented for the first time. The fourth observability index is proved to be the unique criterion for the best pose set in robot calibration. Experimental results are compared with the results obtained using an external calibration device. / In the second part of the thesis, dynamics and friction modeling of the Utah/MIT Dextrous Hand is sought. These models along with actuator model are used in a low level model based force control. It is shown that tendon dynamics does not affect the control performance. On the other hand, it is shown that friction is a major factor which should not be neglected in the force control. The improvements achieved by the feed-forward terms are illustrated. Actuator saturation is rigorously investigated. It is shown that the maximum force bandwidth before the occurrence of saturation is 10 Hz.

A Control Volume Finite Difference (CVFD) code which finds the heat transfer coefficients resulting in a calculated thermal field that matches the thermal field obtained in experiments, was developed. The code is capable of solving unsteady conduction. and convection-diffusion problems in two or three dimensions using cylindrical coordinates. / The complex problem of the workpiece cooling, was decomposed into smaller sub-problems corresponding to the different cooling zones. For each sub-problem an inverse-problem approach was applied using data from cooling experiments as a reference. / As the result, the heat transfer coefficients were determined for a workpiece cooling in air, including the effect of the chuck, and by impinging coolant jet. The latter is defined by a distribution function. / The thermal field calculated using the heat transfer coefficients determined in this research was found to be in reasonable agreement with the thermal field obtained from experiments conducted during cutting.

Today, many companies are interested in improving their competitive position in the marketplace, and hence, compete by bringing new products and value added services to the market in a timely fashion, at low cost and enhanced quality. Concurrent Engineering (CE), a new methodology and a systematic approach to the integrated design of products and related processes including manufacture and support is ideal, for this environment. / Organizations implement CE to achieve specific goals. This thesis focuses on the goals of time, cost and quality for implementing CE. The existence of specific models or methods of implementation of CE for specific goals has been investigated and metrics for specific models classified. Case studies of organizations implementing CE are outlined and differences in implementations pointed out. Organizations focusing on time put. more emphasis on stages/activities between detailed specification and detailed design stages in a CE NPD process. Organizations focusing on quality and cost put more emphasis on the stages/activities between preliminary design and volume production. / Metrics for CE processes targeting specific goals have also been classified. However, it has been found that metrics are not restricted to specific goals.

Over the past twenty-five years, there has been considerable research devoted to the development of Reynolds stress turbulence models. One particular research area is the development of representations for the pressure-strain correlation which reliably account for the effects of solid walls with complex geometries. This thesis is a theoretical and numerical study of a fairly recent method: elliptic relaxation. / There are two challenges in using this method: (1) the determination of appropriate boundary conditions for the elliptic relaxation equations, and (2) the numerical implementation of those boundary conditions in non-Cartesian geometries. In this thesis, a set of 2D boundary conditions are derived via an asymptotic analysis of the Reynolds stress transport equations through the viscous sublayer. 1D and 2D finite volume numerical models to solve two elliptic relaxation models, the k-epsilon- vv model and a Reynolds stress version, are developed. These formulations are then used to compute the steady flow through stationary and rotating plane channels, and through a plane diffuser. The results are compared with benchmark direct numerical simulation and experimental data.

Over the last few decades, much research effort has been focused on legged robots to mimic human or animal behaviors. The main motivation for this research is the fact that the majority of the earth's land mass is inaccessible to wheeled vehicles. It is therefore necessary to develop robots which can deal with a variety of terrain and overcome obstacles---legged locomotion seems to be the answer. / With a new class of four-legged robots---the SCOUT class---maximum mechanical simplicity is achieved with only one actuated degree of freedom per leg. This platform with stiff legs has already been proven by Anca Cocosco to be capable of stable walking with a set of control algorithms based on controlled momentum transfer. By adding compliance in the legs and changing the control strategy to one that resembles Raibert's three-part controller, it has become possible to achieve running gaits in SCOUT-I and SCOUT-II. This will be demonstrated through simulations using the Working Model [8] software package. / This thesis demonstrates that with a very simple mechanical design, simple control strategy, and only one actuated degree of freedom per leg, stable running is possible in SCOUT-II, and this for a variety of speeds and under different initial conditions. This research, along with other research on walking and stair-climbing presently being conducted at the Ambulatory Robotics Laboratory, will pave the way for robots that are inexpensive and of simple mechanical design, yet highly mobile and functional.