Using iterative LQR to control two quadrotors transporting a cable-suspended load

Journal of Mechanisms and Robotics

2019

Aerial cable towed systems (ACTSs) can be created by joining unmanned aerial vehicles (UAVs) to a payload to extend the capabilities of the system beyond those of an individual UAV. This paper describes a systematic method for evaluating the available wrench set and the robustness of equilibrium of ACTSs by adapting wrench analysis techniques used in traditional cable-driven parallel robots to account for the constraints of quadrotor actuation and dynamics. Case studies and experimental results are provided to demonstrate the analysis of different classes of ACTSs, as a means of evaluating the design and operating configurations.

Section: Spatial System With 8 Quadrotors and 8 Cablesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Wrench Analysis of Cable-Suspended Parallel Robots Actuated by Quadrotor Unmanned Aerial Vehicles

Journal of Mechanisms and Robotics

2019

“…The robot can therefore be considered as a 3-PPPSS mechanism. The loop closure equation for the limb i is given by (4), with x p being the cartesian coordinate vector of the payload # » OP expressed in F 0 .…”

Section: B Kinematic Modelling Of the Actsmentioning

confidence: 99%

“…Studies of aerial cable towed systems (ACTSs) have focused primarily on designing controllers to stabilize the payload and quadrotors using a variety of methods, both in quasi-static and dynamic scenarios. In [4], [5], the control is achieved using a linear quadratic regulator (LQR). In [6], ACTSs are proven to be differentially flat, and a dynamic control based on differentially flat trajectories 1É cole Centrale de Nantes (ECN), Laboratoire des Sciences du Numérique de Nantes (LS2N), UMR CNRS 6004, 1 rue de la Noe, 44321 Nantes, France.…”

Section: Introductionmentioning

confidence: 99%

Control and Configuration Planning of an Aerial Cable Towed System

2019 International Conference on Robotics and Automation (ICRA)

2019

This paper investigates the effect of the robot configuration on the performance of an aerial cable towed system (ACTS) composed of three quadrotors manipulating a point mass payload. The kinematic and dynamic models of the ACTS are derived in a minimal set of geometric coordinates, and a centralized feedback linearization controller is developed. Independent to the payload trajectory, the configuration of the ACTS is controlled and is evaluated using a robustness index named the capacity margin. Experimental validation is performed with optimal, suboptimal, and wrench infeasible configurations. It is shown that configurations near the point of zero capacity margin allow the ACTS to hover but not to follow dynamic trajectories, and that the ACTS cannot fly with a negative capacity margin. Dynamic tests are performed on the ACTS, showing the effects of the configuration on the achievable accelerations.

“…In [5], differential flatness is used to generate feasible trajectories for the system. The authors of [6] use control methods adapted from cable-driven parallel robots (CDPRs) to ensure stability and trajectory convergence, while in [7], a linear quadratic regulator is used to control the robot. In [8], a novel ACTS is presented and uses RRT graphs to determine feasible payload trajectories.…”

Section: Introductionmentioning

confidence: 99%

Wrench Capability Analysis of Aerial Cable Towed Systems

Volume 5A: 42nd Mechanisms and Robotics Conference

2018

Aerial cable towed systems (ACTSs) can be created by joining unmanned aerial vehicles (UAVs) to a payload to extend the capabilities of the system beyond those of an individual UAV. This paper describes a systematic method of evaluating the available wrench set and the robustness of equilibrium of ACTSs by adapting wrench analysis techniques used in cable-driven parallel robots to account for the constraints of quadrotor actuation. Case studies are provided to demonstrate the analysis of different classes of ACTSs, as a means of evaluating the design and operating configurations.