Robots

This thesis presents a mapping and navigation system intended for an unmanned untethered underwater vehicle. The system utilizes range data obtained from a time of flight sonar operating at 307KHz. The range data, along with an angle measurement of the transducer, is used to generate a simple object map (detected object and its position in two dimensions). The raw range data is filtered using an edge detection algorithm. The edge detection algorithm extracts possible corners from the acoustic data of the scanned environment. The output of the edge detection algorithm is sent to a confidence program. The confidence program determines which of the possible "corners", determined by the edge detection algorithm, are "actual" corners. The output of the confidence program is then used to produce the object map. This object map may be used as the input to an annotated map-builder. The output of the confidence program is then input to the navigation system. The navigation system determines the position of the vehicle relative to a detected object without any a-priori information, which may be used as an input to a path planner and an obstacle avoidance system. The experiments were carried out in a 25 x 30 foot pool and the experimental data processed on a Sun Workstation using Matlab and C generated code for post-processing of the raw acoustical data.

In this thesis, a novel two-dimensional learning control scheme for robot manipulators is proposed. The convergence of the scheme for a general n-degree of freedom robot is shown. In the next part of the thesis, an algorithm for the approximation of a two-dimensional causal, recursive, separable-in-denominator (CRSD) filter, using the impulse response and autocorrelation data, is presented. The stability of the designed filter is discussed and it is shown that the approximated filter is always stable. The simulation results for the approximation technique as well as the two-dimensional learning control scheme are also included in the thesis.

Central to many manipulator positional control schemes is a requirement to invert the forward kinematic equations which model the given manipulator. It is shown in this thesis that for manipulator types where a common wrist center exists, a simplified Jacobian form is feasible and its inversion can be used in place of inverse kinematic solutions for positional control. The Jacobian simplification is obtained by decoupling of the wrist member from the positional member, resulting in a Jacobian inversion involving the solution of two sets of three equations with three unknowns. Within the development of the alternate Jacobian form, a technique for substituting incremental rotations with incremental translations is introduced yielding better insight into the Jacobian structure. A requirement for small moves is validated with a discussion of a proposed positional control strategy and a comprehensive example is presented as a summary of the results.

The concept of "generalized manipulator" is introduced, and
the closed form and recursive form dynamical models of the
generalized manipulator are presented in Newton-Euler
formulation. The physical meaning of each term in the
dynamical model is explained.
The dynamical models formulated by the Newton-Euler method
and the Lagrangian-Euler method are proved equivalent. The
dynamical model of the generalized manipulator is reduced to
ordinary manipulators. The reduced dynamical model is shown
identical to existing models. Furthermore, the reduced
dynamical model of the generalized manipulator can be used
to compute forces and torques components along any
direction.
Application of the model to problems of mobile robots and
flexible manipulators is shown.

The primary objective of this research is the development a wind and solar-powered autonomous surface vehicle (WASP) for oceanographic measurements. This thesis presents the general design scheme, detailed aerodynamic and hydrodynamic aspects, sailing performance theory, and dynamic performance validation measurements obtained from a series of experiments. The WASP consists of a 4.2 meter long sailboat hull, a low-Reynolds number composite wing, a 2000 Watt-hour battery reservoir, a system of control actuators, a control system running on an embedded microprocessor, a suite of oceanographic sensors, and power regeneration from solar energy. The vehicle has a maximum speed of five knots and weighs approximately 350 kilograms. Results from four oceanographic missions that were conducted in the Port Everglades Intracoastal Waterway in Dania Beach [sic] Florida are presented. Water temperature, salinity and oxidation-reduction measurements recorded during these missions are also discussed. The combination of a mono-hull and solid wing in an autonomous system is a viable design for a long-range ocean observation platform. The results of four near-shore ocean observation missions illustrate the initial capabilities of the design. Future work aimed to further reduce both the mass of the wing design and the power requirements of the system will increase performance in all operating conditions and should be considered. Furthermore, the progression of the legal framework related to ocean vehicles must be pursued with respect to unmanned autonomous systems.