PhD Oral Exam - Walaaeldin Ahmed, Electrical and Computer Engineering

When studying for a doctoral degree (PhD), candidates submit a thesis that provides a critical review of the current state of knowledge of the thesis subject as well as the student’s own contributions to the subject. The distinguishing criterion of doctoral graduate research is a significant and original contribution to knowledge.

Once accepted, the candidate presents the thesis orally. This oral exam is open to the public.

Abstract

Robots are increasingly used in industry as well as in real life applications, specially in environments characterized by dangerous materials. Wheeled mobile robots are excellent candidates in applications involving point to point motion, path following, or trajectory tracking motions. Among various types of wheeled mobile robots, the two-wheeled mobile robots with a self-balancing third wheel (caster) have been widely considered in the literature and applications due to its simple kinematic and dynamic model. One of the important such applications is the patrolling operation for the purpose of monitoring and surveillance of an area of interest. In particular, this research studies the use of the two-wheeled mobile robots in patrolling operations and aims at obtaining the most distance-efficient as well as time-efficient output trajectories by solving constrained optimization problems.

This problem is directly related to the well-known Traveling Salesman Problem (TSP) and its variants in which a salesman is required to start from a base city and visit a number of cities with minimum travel distance while satisfying the constraints that each city has to be visited only once. Finally the salesman returns back to the starting base city after completing the mission. 

Different patrolling configurations that are related to the variants of the TSP are investigated. The Single Depot multiple Traveling Salesman Problem (mTSP) as well as the Multidepot multiple Traveling Salesman Problem (MmTSP). Different algorithms are introduced for the trajectory planning of multiple two-wheeled mobile robots, either with two differential motors so that they can turn on the spot, or with Dubins-like vehicles. The output trajectories for both types of wheeled-robots would be investigated by using a model predictive control algorithm to ensure their kinematic feasibility for the best monitoring performance. The schemes and strategies developed in this research will be verified by a series of simulations using well-known programming and optimization softwares as well as practical implementations in the lab.