TY - JOUR
T1 - Estimation of inertial properties for a multilift slung load
AU - Geng, Junyi
AU - Langelaan, Jack W.
N1 - Funding Information:
This research was partially funded by the U.S. Government under Agreement No. W911W6-17-2-0003. The U.S. Government is authorized to reproduce and distribute reprints for Government purposes notwithstanding any copyright notation thereon. The views and conclusions contained in this document are those of the authors and should not be interpreted as representing the official policies, either expressed or implied, of the Aviation Development Directorate or the U.S. Government.
Publisher Copyright:
© 2020 by Junyi Geng and Jack W. Langelaan. Published by the American Institute of Aeronautics and Astronautics, Inc.
PY - 2021
Y1 - 2021
N2 - A method to estimate mass, center of mass, and moments of inertia of a multilift slung load is described. An analysis of system dynamics relates slung load response to cable tension, and a means to estimate cable tension without a direct cable force sensor is described. Three different estimators (least squares, maximum likelihood, and Kalman filter) are derived and compared for this estimation problem. Flight tests performed in a motion capture studio are used to demonstrate the utility of the proposed approach. Payload mass is estimated with less than 3% error without the use of a cable tension sensor. Mass added to the payload to intentionally change the center of mass and moment of inertia is used to verify the estimation of center of mass and moment of inertia, with center of mass estimates estimated to well within one centimeter of the true location. Trajectory tracking tests comparing uncompensated (i.e., nominal) center of mass and compensated (estimated) center of mass show that payload position tracking is essentially unchanged. However, payload orientation, cable tension, and rotorcraft position tracking are significantly improved when the estimated center of mass is incorporated into the feedback loop.
AB - A method to estimate mass, center of mass, and moments of inertia of a multilift slung load is described. An analysis of system dynamics relates slung load response to cable tension, and a means to estimate cable tension without a direct cable force sensor is described. Three different estimators (least squares, maximum likelihood, and Kalman filter) are derived and compared for this estimation problem. Flight tests performed in a motion capture studio are used to demonstrate the utility of the proposed approach. Payload mass is estimated with less than 3% error without the use of a cable tension sensor. Mass added to the payload to intentionally change the center of mass and moment of inertia is used to verify the estimation of center of mass and moment of inertia, with center of mass estimates estimated to well within one centimeter of the true location. Trajectory tracking tests comparing uncompensated (i.e., nominal) center of mass and compensated (estimated) center of mass show that payload position tracking is essentially unchanged. However, payload orientation, cable tension, and rotorcraft position tracking are significantly improved when the estimated center of mass is incorporated into the feedback loop.
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U2 - 10.2514/1.G005365
DO - 10.2514/1.G005365
M3 - Article
AN - SCOPUS:85100648976
SN - 0731-5090
VL - 44
SP - 220
EP - 237
JO - Journal of Guidance, Control, and Dynamics
JF - Journal of Guidance, Control, and Dynamics
IS - 2
ER -