dc.description.abstract | Which technologies and algorithmic design are suitable for both the control strategy
and the communication protocol to ensure robustness within a robotic swarm?
The aim of this study is to answer this question. The study is performed by obtaining an
understanding of the field of swarm robotics and proposing a robotic swarm system with
robustness in mind. The robotic swarm system contains possible solutions for the control
strategy, the communication protocol, hardware design and an in-room localization
method. The innovative part of this swarm system is the idea of joining communication
and control in a cooperative manner, based on previous studies on different robotic swarms.
The communication protocol was designed to establish a mesh topology using the Thread
protocol, MQTT-SN and ROMANOs. ROMANOs is a new application overlay protocol
based on ROMANO, and is first introduced in this project. The control strategy introduces
a potential-field based PID-controller, designed for its efficiency and practical approach.
The cooperation between communication and control is the fact that the estimation of
signal strength values will directly affect the potential fields of the control strategy. The
control strategy will then initiate control actions to maintain the communication network.
The hardware design platform consists of two printed circuit boards that houses all necessary
electronics to realize the swarm algorithm, and a 3D-printed cylindrical chassis. The
in-room localization method is based on ranging measurements from laser sensors, signal
strength estimates and heading computations based on magnetometer data. A listening
device consisting of a Node.JS MQTT module is created in order to acquire performance
data from the swarm which is stored in an SQL database and further analysed in MATLAB.
The proposed swarm application yields a mostly favorable, but mixed result. The joint
control- and communication algorithm is successful in finding a local minima within the
network and maintaining said network. However, some parts of the algorithm are taxing
and could be further refined. The communication protocol is only able to maintain a
messaging frequency of up to 5 Hz for a six-member swarm, and the processor is only able
to run the proposed swarm algorithm at a maximum of 50 Hz. What measures that should
be taken to mitigate this and future work for this swarm application will be proposed.
Nevertheless could the proposed swarm application work as an important stepping-stone
for a true robust swarm application in the future.
Keywords : robotic swarms, potential-field based control, thread mesh network, MQTTSN,
ROMANO, laser distance measurements, magnetometer, joint control- and communication
algorithm, PCB design, algorithm design, robust swarm application | |