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No description available.

No description available.

No description available.

This dissertation deals with the control, guidance and stabilisation of nonlinear, non¬holonomic systems. It is shown that the kinematics of the system can be separated from the dynamics of the system by using successively two inverse dynamics type of transformations. This leads to a linear decoupled kinematical system, control strategies can then be developed that directly control the motion of the system. The method is applied to a system which is composed of a disk rolling on a plane, a controlled slender rod that is pivoted through its center of mass about the disk's center and two overhead rotors with their axes fixed in the upper part of the rod. Control strategies are designed under which the disk's inclination is stabilised about its vertical position and the disk's motion is able to asymptotically track any given smooth ground trajectory. The control strategy is shown to be stable in the presence parametric uncertainties. It was furthermore shown that the system is path controllable. Finally an extended inverse dynamics control law is introduced which deals directly with underactuated systems. An example of an articulated crane is solved using extended inverse dynamics control. Feasible control is used to ensure that the internal dynamics of the system remains bounded and that the crane reach its desired final position in a given time interval [O, tƒ]. / Dissertation (MSc (Applied SCience))--University of Pretoria, 2007. / Electrical, Electronic and Computer Engineering / unrestricted

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For the successful deployment of task-achieving multi-robot systems (MRS), the interactions must be coordinated among the robots within the MRS and between the robots and the task environment. There have been a number of impressive experimentally demonstrated coordinated MRS. However it is still of a premature stage for real world applications. This dissertation presents an MRS control scheme using Artificial Immune Systems (AIS). This methodology is firmly grounded in the biological sciences and provides robust performance for the intertwined entities involved in any task-achieving MRS. Based on its formal foundation, it provides a platform to characterize interesting relationships and dependencies among MRS task requirements, individual robot control, capabilities, and the resulting task performance. The work presented in this dissertation is a first of its kind wherein the principles of AIS have been used to model and organize the group behavior of the MRS. This has been presented in the form of a novel algorithm. In addition to the above, generic environments for computer simulation and real experiment have been realized to demonstrate the working of an MRS. These could potentially be used as a test bed to implement other algorithms onto the MRS. The experiment in this research is a bomb disposal task which involves a team of three heterogeneous robots with different sensors and actuators. And the algorithm has been tested practically through computer simulations.

published_or_final_version / Electrical and Electronic Engineering / Doctoral / Doctor of Philosophy

published_or_final_version / Electrical and Electronic Engineering / Doctoral / Doctor of Philosophy

published_or_final_version / abstract / Industrial and Manufacturing Systems Engineering / Doctoral / Doctor of Philosophy