Cooperative Behavioural Control for Omni-Wheeled Robots: Experiments and simulations for formation control with obstacle- and collision avoidance

This thesis considers the formation and behavioural control problem of a multirobotsystem. A mathematical model of the mobile vehicles are presented, followedby an introduction to behavioural control. The Null-Space based Behavioural(NSB) control [Antonelli, Arrichiello, and Chiaverini, 2005] is presented, and isused to create task functions for obstacle- and collision avoidance. The formationproblem is solved by a passivity based approach presented in [Arcak, 2007]. Thetwo controllers are combined to create a complete controller capable of maintaininggroup formations, while avoiding obstacles and inter-agent collisions. The resultsare verified by simulations and experiments on custom built robots

Suspended Load Motion Control using Multicopters

This paper presents a distributed kinematic control law for group coordination for several multicopters and a payload suspended with wires from each multicopter. The complete system with constraints on the wires are modeled in 6 degrees of freedom (DOF), using the Udwadia-Kalaba equation. Velocity controllers for the multicopters are developed to realize the desired motion set by the kinematic controller. This results in a system where the group of multicopters are able to maneuver the payload to a desired position while keeping a desired formation. The results are verified by simulations

Nonlinear Control with Swing Damping of a Multirotor UAV with Suspended Load

In this paper, we consider the problem of trajectory tracking of a multirotor Unmanned Aerial Vehicle carrying a suspended payload. The movement of the suspended payload influences the dynamics of the multirotor, which must be appropriately handled by the controller to achieve satisfactory tracking results. We derive a mathematical model of the interconnected multi-body system using Kane’s equations, and develop a non-linear tracking controller based on the backstepping technique. In addition to suppressing the effects of the swinging payload, the controller also compensates for an unknown constant wind disturbance. The origin of the tracking error is proven UGAS (Uniformly Globally Asymptotically Stable) and ULES (Uniformly Locally Exponentially Stable) through Lyapunov analysis. To reduce the swing motion of the suspended load, a nominal swing-free path is generated through open loop shaping filters, then further perturbed through a delayed feedback approach from measured load deflection angles to achieve robustness. The proposed controller structure is verified by simulations and experiments

Nonlinear Control of a Multirotor UAV with Suspended Load

Abstract-This paper considers the control of a multirotor-type unmanned aerial vehicle (UAV) with a suspended load. The load is modeled as a pendulum, with a rigid link. We consider the case when the suspended load is connected to the centre of gravity of the UAV, and the interconnected system is modeled by Kane's method. A nonlinear controller based on the backstepping technique is derived, that ensures trajectory tracking of the UAV regardless of the pendulum motion. The origin of the tracking error is proved to be globally asymptotically stable, and results are verified by simulations

Autonomous recovery of a fixed-wing UAV using a net suspended by two multirotor UAVs

This article presents a novel recovery method for fixed‐wing unmanned aerial vehicles (UAVs), aimed at enabling operations from marine vessels. Instead of using the conventional method of using a fixed net on the ship deck, we propose to suspend a net under two cooperative multirotor UAVs. While keeping their relative formation, the multirotor UAVs are able to intercept the incoming fixed‐wing UAV along a virtual runway over the sea and transport it back to the ship. In addition to discussing the concept and design a control system, this paper also presents experimental validation of the proposed concept for a small‐scale UAV platform

Suspended load motion control using multicopters

This paper presents a distributed kinematic control law for group coordination for several multicopters and a payload suspended with wires from each multicopter. The complete system with constraints on the wires are modeled in 6 degrees of freedom (DOF), using the Udwadia-Kalaba equation. Velocity controllers for the multicopters are developed to realize the desired motion set by the kinematic controller. This results in a system where the group of multicopters are able to maneuver the payload to a desired position while keeping a desired formation. The results are verified by simulations