On Coverage Control for Limited Range Multi-Robot Systems

This paper presents a coverage based control algorithm to coordinate a group of autonomous robots. Most of the solutions presented in the literature rely on an exact Voronoi partitioning, whose computation requires complete knowledge of the environment to be covered. This can be achieved only by robots with unlimited sensing capabilities, or through communication among robots in a limited sensing scenario. To overcome these limitations, we present a distributed control strategy to cover an unknown environment with a group of robots with limited sensing capabilities and in the absence of reliable communication. The control law is based on a limited Voronoi partitioning of the sensing area, and we demonstrate that the group of robots can optimally cover the environment using only information that is locally detected (without communication). The proposed method is validated by means of simulations and experiments carried out on a group of mobile robots

Obstacle avoidance of non-holonomic unicycle robots based on fluid mechanical modeling

This paper is concerned with obstacle avoidance of robots moving on a plane, based on a fluid mechanical principle known as the Circle Theorem. Considering the motion region as a fictitious fluid environment surrounding the obstacles, fluid streamlines are calculated which correspond to unique smooth paths that a mobile robot can follow without colliding with the obstacles. The design and analysis are initially performed assuming simple integrator dynamics for the agent, and later extended for more realistic non-holonomic unicycle dynamic agent models, with the help of proportional integral (PI) control and backstepping principles. Both point and non-point (ellipse) geometric models are considered for the agents in design and analysis. The fluid dynamics based designs developed for obstacle avoiding motion control of agents with non-holonomic unicycle dynamics are novel, and successfully tested via an extensive set of simulations. Application of the developed designs for motion control of unmanned aerial vehicles (UAVs) under the constraint of constant speed is also presented

Obstacle Avoidance of Non-holonomic Unicycle Robots Based on Fluid Mechanical Modeling

This paper is concerned with obstacle avoidance of robots moving on a plane, based on a fluid mechanical principle known as the Circle Theorem. Considering the motion region as a fictitious fluid environment surrounding the obstacles, fluid streamlines are calculated which correspond to unique smooth paths that a mobile robot can follow without colliding with the obstacles. The design and analysis are initially performed assuming simple integrator dynamics for the agent, and later extended for more realistic non-holonomic unicycle dynamic agent models, with the help of proportional integral (PI) control and backstepping principles. Both point and non-point (ellipse) geometric models are considered for the agents in design and analysis. The fluid dynamics based designs developed for obstacle avoiding motion control of agents with non-holonomic unicycle dynamics are novel, and successfully tested via an extensive set of simulations. Application of the developed designs for motion control of unmanned aerial vehicles (UAVs) under the constraint of constant speed is also presented

A non-holonomic, highly human-in-the-loop compatible, assistive mobile robotic platform guidance navigation and control strategy

The provision of assistive mobile robotics for empowering and providing independence to the infirm, disabled and elderly in society has been the subject of much research. The issue of providing navigation and control assistance to users, enabling them to drive their powered wheelchairs effectively, can be complex and wide-ranging; some users fatigue quickly and can find that they are unable to operate the controls safely, others may have brain injury re-sulting in periodic hand tremors, quadriplegics may use a straw-like switch in their mouth to provide a digital control signal. Advances in autonomous robotics have led to the development of smart wheelchair systems which have attempted to address these issues; however the autonomous approach has, ac-cording to research, not been successful; users reporting that they want to be active drivers and not passengers. Recent methodologies have been to use collaborative or shared control which aims to predict or anticipate the need for the system to take over control when some pre-decided threshold has been met, yet these approaches still take away control from the us-er. This removal of human supervision and control by an autonomous system makes the re-sponsibility for accidents seriously problematic. This thesis introduces a new human-in-the-loop control structure with real-time assistive lev-els. One of these levels offers improved dynamic modelling and three of these levels offer unique and novel real-time solutions for: collision avoidance, localisation and waypoint iden-tification, and assistive trajectory generation. This architecture and these assistive functions always allow the user to remain fully in control of any motion of the powered wheelchair, shown in a series of experiments