428 research outputs found
Circular formation control of fixed-wing UAVs with constant speeds
In this paper we propose an algorithm for stabilizing circular formations of
fixed-wing UAVs with constant speeds. The algorithm is based on the idea of
tracking circles with different radii in order to control the inter-vehicle
phases with respect to a target circumference. We prove that the desired
equilibrium is exponentially stable and thanks to the guidance vector field
that guides the vehicles, the algorithm can be extended to other closed
trajectories. One of the main advantages of this approach is that the algorithm
guarantees the confinement of the team in a specific area, even when
communications or sensing among vehicles are lost. We show the effectiveness of
the algorithm with an actual formation flight of three aircraft. The algorithm
is ready to use for the general public in the open-source Paparazzi autopilot.Comment: 6 pages, submitted to IROS 201
Comprehensive review on controller for leader-follower robotic system
985-1007This paper presents a comprehensive review of the leader-follower robotics system. The aim of this paper is to find and elaborate on the current trends in the swarm robotic system, leader-follower, and multi-agent system. Another part of this review will focus on finding the trend of controller utilized by previous researchers in the leader-follower system. The controller that is commonly applied by the researchers is mostly adaptive and non-linear controllers. The paper also explores the subject of study or system used during the research which normally employs multi-robot, multi-agent, space flying, reconfigurable system, multi-legs system or unmanned system. Another aspect of this paper concentrates on the topology employed by the researchers when they conducted simulation or experimental studies
Distributed coordinate tracking control of multiple wheeled mobile robots
In this thesis, distributed coordinate tracking control of multiple wheeled-mobile robots is studied. Control algorithms are proposed for both kinematic and dynamic models. All vehicle agents share the same mechanical structure. The communication topology is leader-follower topology and the reference signal is generated by the virtual leader. We will introduce two common kinematic models of WMR and control algorithms are proposed for both kinematic models with the aid of graph theory. Since it is more realistic that the control inputs are torques so dynamic extension is studied following by the kinematics. Torque controllers are designed with the aid of backstepping method so that the velocities of the mobile robots converge to the desired velocities. Because of the fact that in practice, the inertial parameter of WMR maybe not exactly known or even unknown, so both dynamics with and without inertial uncertainties are considered in this thesis
A snake-based scheme for path planning and control with constraints by distributed visual sensors
YesThis paper proposes a robot navigation scheme using wireless visual sensors deployed in an environment.
Different from the conventional autonomous robot approaches, the scheme intends to relieve massive on-board
information processing required by a robot to its environment so that a robot or a vehicle with less intelligence can
exhibit sophisticated mobility. A three-state snake mechanism is developed for coordinating a series of sensors to
form a reference path. Wireless visual sensors communicate internal forces with each other along the reference snake
for dynamic adjustment, react to repulsive forces from obstacles, and activate a state change in the snake body from a
flexible state to a rigid or even to a broken state due to kinematic or environmental constraints. A control snake is
further proposed as a tracker of the reference path, taking into account the robot’s non-holonomic constraint and
limited steering power. A predictive control algorithm is developed to have an optimal velocity profile under robot
dynamic constraints for the snake tracking. They together form a unified solution for robot navigation by distributed
sensors to deal with the kinematic and dynamic constraints of a robot and to react to dynamic changes in advance.
Simulations and experiments demonstrate the capability of a wireless sensor network to carry out low-level control
activities for a vehicle.Royal Society, Natural Science Funding Council (China
An Overview of Recent Progress in the Study of Distributed Multi-agent Coordination
This article reviews some main results and progress in distributed
multi-agent coordination, focusing on papers published in major control systems
and robotics journals since 2006. Distributed coordination of multiple
vehicles, including unmanned aerial vehicles, unmanned ground vehicles and
unmanned underwater vehicles, has been a very active research subject studied
extensively by the systems and control community. The recent results in this
area are categorized into several directions, such as consensus, formation
control, optimization, task assignment, and estimation. After the review, a
short discussion section is included to summarize the existing research and to
propose several promising research directions along with some open problems
that are deemed important for further investigations
Formation of Multiple Groups of Mobile Robots Using Sliding Mode Control
Formation control of multiple groups of agents finds application in large
area navigation by generating different geometric patterns and shapes, and also
in carrying large objects. In this paper, Centroid Based Transformation (CBT)
\cite{c39}, has been applied to decompose the combined dynamics of wheeled
mobile robots (WMRs) into three subsystems: intra and inter group shape
dynamics, and the dynamics of the centroid. Separate controllers have been
designed for each subsystem. The gains of the controllers are such chosen that
the overall system becomes singularly perturbed system. Then sliding mode
controllers are designed on the singularly perturbed system to drive the
subsystems on sliding surfaces in finite time. Negative gradient of a potential
based function has been added to the sliding surface to ensure collision
avoidance among the robots in finite time. The efficacy of the proposed
controller is established through simulation results.Comment: 8 pages, 5 figure
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