Suspended load motion control using multicopters

Abstract

Abstract-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.

Cooperative Control for Multirotors Transporting an Unknown Suspended Load Under Environmental Disturbances

“…The control strategy presented in Section III assumes these forces are unknown, so they don't need to be measured or estimated explicitly. This technique has previously been applied to similar systems in [22], [23], in which details on the derivations can be found.…”

Passivity-based Formation Control for UAVs with a Suspended Load

“…The dynamics of each UAV are described by point mass models, as in Mahony et al (2012); Klausen et al (2014), of the form…”

“…For example, Mellinger et al (2013); Michael et al (2011) assume external cameras are available to provide accurate position measurements of the UAVs and the payload, which limits the applicability of these approaches for large scale, outdoor environments. Alternatively, in Klausen et al (2014); Maza et al (2009); Bernard and Kondak (2009) ;Bernard et al (2011) sensors onboard the UAVs are used to measure the relative positions of the UAVs and the payload, and use only these measurements to maintain a constant formation. In this paper we assume that the UAVs only measure their relative positions and not the position of the suspended load.…”

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

“…The direction of applied force is given by R i , which corresponds to specifying the roll-and pitch-angle of the vehicle. Since we assume a sufficiently fast low-level attitude controller is present on the multirotor UAV is present (examples of such is given in (Mahony et al, 2012) and (Klausen et al, 2014)), the term R i e 3 f i can be replaced by an inertial control force F i ∈ R 3 , resulting in the dynamics…”