Virtual Sensing Technology applied to a swarm of autonomous robots

This thesis proposes a novel technology in the field of swarm robotics that allows a swarm of robots to sense a virtual environment through virtual sensors. Virtual sensing is a desirable and helpful technology in swarm robotics research activity, because it allows the researchers to efficiently and quickly perform experiments otherwise more expensive and time consuming, or even impossible. In particular, we envision two useful applications for virtual sensing technology. On the one hand, it is possible to prototype and foresee the effects of a new sensor on a robot swarm, before producing it. On the other hand, thanks to this technology it is possible to study the behaviour of robots operating in environments that are not easily reproducible inside a lab for safety reasons or just because physically infeasible. The use of virtual sensing technology for sensor prototyping aims to foresee the behaviour of the swarm enhanced with new or more powerful sensors, without producing the hardware. Sensor prototyping can be used to tune a new sensor or perform performance comparison tests between alternative types of sensors. This kind of prototyping experiments can be performed through the presented tool, that allows to rapidly develop and test software virtual sensors of different typologies and quality, emulating the behaviour of several hardware real sensors. By investigating on which sensors is better to invest, a researcher can minimize the sensors’ production cost while achieving a given swarm performance. Through augmented reality, it is possible to test the performance of the swarm in a desired virtual environment that cannot be set into the lab for physical, logistic or economical reasons. The virtual environment is sensed by the robots through properly designed virtual sensors. Virtual sensing technology allows a researcher to quickly carry out real robots experiment in challenging scenarios without all the required hardware and environment. Virtual sensor experiments are hybrid experiments between purely simulated and purely real experiments. Indeed, virtual sensors experiments join the real world dynamics of the real robots to the simulated dynamics of the virtual sensors. The benefits of virtual sensing experiments compared to purely real experiments are presented above. The benefit of virtual sensor experiments compared to purely simulated experiment consists in the fact that the former are one step closer to reality than the latter. Hence, hybrid experiments are closer to reality than purely simulated ones. The proposed system is composed of a tracking system, a simulator and a swarm of robots. The multi-camera tracking system acquires the position of the robots in the arena. This information is then processed inside a simulator, and the output is delivered to the real robots as virtual sensor values. In Chapter 2, I describe the functioning of the tracking system. In Chapter 3, I present the components of the simulator that realize the virtual sensing environment. In Chapter 4, I illustrate the implementation of three virtual sensors. In Chapter 5, I illustrate the effectiveness of the proposed technology by presenting a simple experiment involving a swarm of 15 robots. This work led to the writing of an international conference article that has been lately submitted [18]. Moreover, working on the presented technology, I had the chance to collaborate to a set of scientific experiments that resulted in an international conference paper [6] and an international journal article currently under review [5]. Furthermore, I contributed to