Cooperative Load Transportation With Two Quadrotors Using Adaptive Control

Abstract

The problem of carrying a bar-shaped payload suspended by flexible cables attached to two quadrotors is analyzed in this work. The aerial vehicles and the load are dealt with as a single system, whose kinematics is described as a multi-robot formation using the virtual structure approach. The dynamic effects caused by the tethered load over the quadrotors, as well as those caused by each quadrotor over the other, are treated by an adaptive dynamic compensator. To validate the proposal, experiments were run testing the system in adverse conditions: transportation far from quasi-static motion, high payload-to-quadrotor weight ratio, 20% of error in the robot model parameters, transportation under wind disturbances, and payload weight changes during flight. The good performance of the proposed control system in all these tests allows concluding that the proposed system is able to accomplish payload positioning, orientation, and trajectory tracking under adverse conditions, with accelerations up to 1.6 m/s 2 .

A Novel Neural Network-Based Robust Adaptive Formation Control for Cooperative Transport of a Payload Using Two Underactuated Quadcopters

“…There are several research works on cooperative payload transport using quadcopters, such as payload transport by gripping with a robotic arm [15]- [17] and payload transport using cables or ropes [18]- [22]. Each of these methods of payload transport has its advantages and disadvantages; in the use of gripping with a robotic arm, the payload does not oscillate, but it causes increased inertia, high cost, and high energy consumption.…”

“…Where ε ρ > 0 and η ρ > 0(ρ = z, ψ) are the switching parameters. Remark 2: To solve the chattering problem, in the control laws designed in (22), the sign(.) function is substituted by the tanh(.)…”

“…function. Theorem 1: The control inputs designed in (22) with the nonlinear disturbance observer in ( 14) guarantee the asymptotic stability of the cooperative transport system such that the output states [z i , ψ i ] T converge to their desired values in a finite time. Furthermore the errors in (17) converge to zero in a finite time.…”

“…The time derivative of (23) and substituting ( 16), ( 19), ( 20) and (22), the following expressions are obtained:…”

Equilibria, Stability, and Sensitivity for the Aerial Suspended Beam Robotic System subject to Model Uncertainty

“…A standard system that has attracted substantial interest in the research community is composed of two aerial vehicles manipulating a beam-like load through cables [22], [23], [24], [17], [25], [26], [27]. Such standard configuration is of interest for several real-world applications, especially in the construction field, where we find columns, wooden pillars, iron beams for cement walls, scaffolds, pipes, pieces of roofs, and other beam-like building elements.…”