A nonlinear force observer for quadrotors and application to physical interactive tasks

Yüksel, Burak; Secchi, Cristian; Bülthoff, HH; Franchi, Antonio

doi:10.1109/aim.2014.6878116

Cited by 73 publications

(79 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As a conclusion, although the ground effect in multirotors (multiple coplanar rotors) has been assumed by most researchers to be the same as for helicopters (a single rotor) [18][19][20][21][22][23][24][25][26][27][28][29] and be significant up to distances to the ground of 2 rotor radii, the results presented in this section show clearly that this is not the case; the ground effect for multirotors is much larger, being significant for distances to the ground of up to 5 rotor radii. Although the PFI can be expanded to include the contributions of all the rotors of a quadrotor (see (3)), the addition of a body lift term with an empirical coefficient (see (4)) reproduces the experimental behavior and can be used in simulations and controller development.…”

Section: Ground Effect For the Full Multirotormentioning

confidence: 72%

“…This control alternative includes a torque disturbance observer that is used to estimate the torque induced by the partial ground effect, caused by the different aerodynamic thrust generated by the rotors when the multirotor is in partial ground effect. Several approaches have been used to estimate external force and torque disturbances in multirotors [22][23][24]38]. In this paper, a nonlinear torque disturbance observer has been implemented [24].…”

Section: Estimated Torquementioning

confidence: 99%

“…Several approaches have been used to estimate external force and torque disturbances in multirotors [22][23][24]38]. In this paper, a nonlinear torque disturbance observer has been implemented [24]. If the multirotor dynamic equations are expressed in compact form (11), the nonlinear observer is able to estimate the forces and torques due to the ground effect GE :…”

Section: Estimated Torquementioning

confidence: 99%

“…Disturbance observers have become popular in the last years for estimating external wrench in multirotors [21,22]. In most cases, it is assumed that the external disturbance source is unique, mainly contact forces [23,24] or wind. In [25], the simultaneous online estimation of aerodynamic and contact forces is studied to discriminate between them and compute the wind velocity by means of model inversion.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Characterization of the Aerodynamic Ground Effect and Its Influence in Multirotor Control

Sanchez-Cuevas

Heredia

Ollero

2017

International Journal of Aerospace Engineering

122

View full text Add to dashboard Cite

This paper analyzes the ground effect in multirotors, that is, the change in the thrust generated by the rotors when flying close to the ground due to the interaction of the rotor airflow with the ground surface. This effect is well known in single-rotor helicopters but has been assumed erroneously to be similar for multirotors in many cases in the literature. In this paper, the ground effect for multirotors is characterized with experimental tests in several cases and the partial ground effect, a situation in which one or some of the rotors of the multirotor (but not all) are under the ground effect, is also characterized. The influence of the different cases of ground effect in multirotor control is then studied with several control approaches in simulation and validated with experiments in a test bench and with outdoor flights.

show abstract

Section: Ground Effect For the Full Multirotormentioning

confidence: 72%

Section: Estimated Torquementioning

confidence: 99%

Section: Estimated Torquementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Characterization of the Aerodynamic Ground Effect and Its Influence in Multirotor Control

Sanchez-Cuevas

Heredia

Ollero

2017

International Journal of Aerospace Engineering

122

View full text Add to dashboard Cite

show abstract

“…Yüksel et. al [10] proposed a non linear force observer, which requires to compute online both the position and attitude up to their 2nd derivatives. In [5] a classical Unscented Kalman Filter is presented to estimate the external force and torque acting on a quadrotor.…”

Section: Introductionmentioning

confidence: 99%

Battery-aware dynamical modeling and identification for the total thrust in multi-rotor UAVs using only an onboard accelerometer

Staub

Franchi

2015

2015 IEEE International Conference on Robotics and Automation (ICRA)

Self Cite

View full text Add to dashboard Cite

Abstract-We propose and experimentally validate a new class of models for the total thrust generation in multi-rotor UAVs which is suitable for low-and middle-end platforms. Differently from typical models assuming to instantaneously control the rotor spinning velocity, in the proposed class we consider that the total thrust has its own dynamics and its final value explicitly depends both on the pseudo-setpoint commands given to the motor driver and the measurement of the battery terminal voltage. We compare the different model instances within the class using a principled experimental setup in which the total thrust is precisely measured using a motion capture system as ground truth, instead of relying on a setup based or noise-prone force sensors. We then show that the use of a dynamical model that includes also the battery terminal voltage significantly improves the prediction ability of the model in terms of accuracy. Finally we show how the proposed model can be identified using on-board only acceleration measurements, achieving a surprisingly good accuracy when compared with the ground truth case. We expect that the use of the proposed model will be important both in case of precise flight control and in the case of aerial physical interactive tasks.

show abstract

A motion control framework for autonomous water sampling and swing‐free transportation of a multirotor UAV with a cable‐suspended mechanism

Panetsos

Karras

Kyriakopoulos

et al. 2023

Journal of Field Robotics

View full text Add to dashboard Cite

In this work, we present an end‐to‐end solution for autonomous water sampling by utilizing an unmanned aerial vehicle (UAV) with a cable‐suspended mechanism. Towards this direction, a sampling mechanism is initially designed in such a manner that the water sampling success ratio is maximized. However, the disturbances, acting on the submerged mechanism due to the water flow during the sampling procedure, impede the stabilization of the vehicle above the desired sampling position. Consequently, to achieve the precise hovering of the UAV, the vehicle's sensor suite is further augmented with a load cell, a depth sensor, an ultrasonic sensor, and a camera. The respective measurements are appropriately fused by employing an extended Kalman filter (EKF). Hence, an estimate of the disturbances is available in real‐time and is incorporated into a Model Predictive Control scheme which compensates for the aforementioned disturbances and stabilizes the vehicle above the sampling location. Finally, a complete water sampling mission entails the safe and swing‐free transportation of the mechanism towards the sampling location and, then, to a position where the collected samples are postprocessed by human operators. Consequently, a model predictive controller is employed which ensures the navigation of the vehicle to the desired waypoints while minimizing the swinging motion of the mechanism. The state of the mechanism is obtained by fusing measurements provided by the load cell and the camera with an EKF. The performance of the proposed framework, which aims to address all the aspects of a water sampling mission, is demonstrated through real experiments with an octorotor.

show abstract

A nonlinear force observer for quadrotors and application to physical interactive tasks

Cited by 73 publications

References 16 publications

Characterization of the Aerodynamic Ground Effect and Its Influence in Multirotor Control

Characterization of the Aerodynamic Ground Effect and Its Influence in Multirotor Control

Battery-aware dynamical modeling and identification for the total thrust in multi-rotor UAVs using only an onboard accelerometer

A motion control framework for autonomous water sampling and swing‐free transportation of a multirotor UAV with a cable‐suspended mechanism

Contact Info

Product

Resources

About