MSc. Thesis Defense:Mohammed Taleb Zamzam11-07-2019

A Novel Coordination Framework for Multi-Robot Systems


Mohammed Taleb Zamzam
Mechatronics, MSc. Thesis, 2019


Thesis Jury

Prof. Dr. Mustafa Ünel (Thesis Advisor), Assoc. Prof. Dr. Kemalettin Erbatur,
Assist. Prof. Dr. Mehmet Selçuk Arslan


Date & Time: July 16th, 2019 – 13:00

Place: FENS G029

Keywords : Multi-Robot Systems, Coordination, Trajectory Planning, UAV, Quadrotor,

Virtual Shells




Having made great progress tackling the basic problems concerning single-robot systems, many researchers shifted their focus towards the study of multi-robot systems (MRS). MRS were shortly found to be a perfect fit for tasks considered to be hard, complex or even impossible for a single robot to perform, e.g. spatially separate tasks. One core research problem of MRS is robots' coordinated motion planning and control. Artificial potential fields (APFs) and virtual spring-damper bonds are among the most commonly used models to attack the trajectory planning problem of MRS coordination. However, although mathematically sound, these approaches fail to guarantee inter-robot collision-free path generation. This is particularly the case when robots' dynamics, nonholonomic constraints and complex geometry are taken into account.

In this thesis, a novel bio-inspired collision avoidance framework via virtual shells is proposed and augmented into the high-level trajectory planner. Safe trajectories can hence be generated for the low-level controllers to track. Motion control is handled by the design of hierarchical controllers which utilize virtual inputs. Several distinct coordinated task scenarios for 2D and 3D environments are presented as a proof of concept. Simulations are conducted with groups of three, four, five and ten nonholonomic mobile robots as well as groups of three and five quadrotor UAVs. The performance of the overall improved coordination structure is verified with very promising results.