Experimental Validation of a New Distributed Cooperative Control Algorithm for Multi-agent Systems with Switching Communication Topologies and Time-Delays

In this thesis, we present practical experimental results to demonstrate a control law for consensus of multiagent systems with switching topologies and time delays. The nonlinear control law utilizes discontinuous cooperative control gains and uses contraction mapping to achieve consensus of multiagent systems. The testing platform we used consists of a number of mobile robots and software simulations both in Matlab and Microsoft Studio C++. We present the effectiveness of the control law design by Aria mobile robots with applications in distributed cooperative formation control. Computer simulations and hardware experiments presented include point consensus control and formation control, both with changing topologies and time-delays. In addition to 2D simulations and experiments, we also developed the 3D model for more practical applications, such as Unmanned Aerial Vehicles (UAVs) and Autonomous Underwater vehicles (AUVs). The research presented was supported by Air Force Research Laboratory / Information Directorate (AFRL/RI)’s Machine Intelligence for Mission Focused Autonomy program. The research presented in this thesis was included in multiple presentations to AFRL program managers, who provided very favorable feedback to our research. Recently, some of our research results was published in the proceedings of 2014 IEEE International Conference on Electro/Information Technology [1], and the paper received Best Paper Award at the conference. In addition, a poster presentation describing our research was made to ERAU College of Engineering’s Industry Advisory Board. The process of implementing the research results in AUVs has also been progressing significantly. Upon invitation, some hardware tests were performed as part of NASA NEEMO 19 (Extreme Environment Mission Operations) experiments, and were subsequently reported twice in the headlines of the Science and Education section in the Daytona Beach News Journal. Technical papers describing proposed cooperative control in AUVs were submitted to 2015 ACM and IEEE conferences. .

Chatter-Free Distributed Control for Multi-agent Nonholonomic Wheeled Mobile Robot

This paper proposes to design a chatter-free distributed control for multiagent nonholonomic wheeled mobile robot systems employing terminal exponential functions with graph theory. The terminal tracking criteria are estimated using the Lyapunov approach. The development of distributed control for nonholonomic multiagent wheeled robot systems is defined in the paper along with consensus tracking for undirected fixed/switched topologies. Numerical simulations have been done in order to assess the efficacy and efficiency of the proposed distributed control method in multiple scenarios

Pose consensus based on dual quaternion algebra with application to decentralized formation control of mobile manipulators

This paper presents a solution based on dual quaternion algebra to the general problem of pose (i.e., position and orientation) consensus for systems composed of multiple rigid-bodies. The dual quaternion algebra is used to model the agents' poses and also in the distributed control laws, making the proposed technique easily applicable to time-varying formation control of general robotic systems. The proposed pose consensus protocol has guaranteed convergence when the interaction among the agents is represented by directed graphs with directed spanning trees, which is a more general result when compared to the literature on formation control. In order to illustrate the proposed pose consensus protocol and its extension to the problem of formation control, we present a numerical simulation with a large number of free-flying agents and also an application of cooperative manipulation by using real mobile manipulators