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Publications (10 of 15) Show all publications
Ho, D., Linder, J., Hendeby, G. & Enqvist, M. (2017). Mass estimation of a quadcopter using IMU data. In: 2017 International Conference on Unmanned Aircraft Systems (ICUAS), June 13-16, 2017, Miami, FL, USA: . Paper presented at 2017 International Conference on Unmanned Aircraft Systems (ICUAS), June 13-16, 2017, Miami, FL, USA (pp. 1260-1266). Institute of Electrical and Electronics Engineers (IEEE)
Open this publication in new window or tab >>Mass estimation of a quadcopter using IMU data
2017 (English)In: 2017 International Conference on Unmanned Aircraft Systems (ICUAS), June 13-16, 2017, Miami, FL, USA, Institute of Electrical and Electronics Engineers (IEEE), 2017, p. 1260-1266Conference paper, Published paper (Refereed)
Abstract [en]

In this paper, an approach to estimate the mass of a quadcopter using only inertial measurements and pilot commands is presented. For this purpose, a lateral dynamic model describing the relation between the roll rate and the lateral acceleration is formulated. Due to the quadcopter’s inherent instability, a controller is used to stabilize the system and the data is collected in closed loop. Under the effect of feedback and disturbances, the inertial measurements used as input and output are correlated with the disturbances, which complicates the parameter estimation. The parameters of the model are estimated using several methods. The simulation and experimental results show that the instrumental-variable method has the best potential to estimate the mass of the quadcopter in this setup.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2017
National Category
Control Engineering
Identifiers
urn:nbn:se:liu:diva-139795 (URN)10.1109/ICUAS.2017.7991417 (DOI)000425255200155 ()9781509044955 (ISBN)9781509044962 (ISBN)
Conference
2017 International Conference on Unmanned Aircraft Systems (ICUAS), June 13-16, 2017, Miami, FL, USA
Projects
MarineUAS
Funder
EU, Horizon 2020, 642153
Note

Funding agencies: European Unions Horizon research and innovation programme under the Marie Sklodowska-Curie grant [642153]

Available from: 2017-08-16 Created: 2017-08-16 Last updated: 2018-03-21Bibliographically approved
Ho, D., Linder, J., Hendeby, G. & Enqvist, M. (2017). Vertical modeling of a quadcopter for mass estimation and diagnosis purposes. In: Proceedings of the Workshop on Research, Education and Development on Unmanned Aerial Systems, RED-UAS, Linköping, Sweden, 3-5 October, 2017: . Paper presented at Workshop on Research, Education and Development on Unmanned Aerial Systems, RED-UAS, Linköping, Sweden, 3-5 October, 2017. Institute of Electrical and Electronics Engineers (IEEE)
Open this publication in new window or tab >>Vertical modeling of a quadcopter for mass estimation and diagnosis purposes
2017 (English)In: Proceedings of the Workshop on Research, Education and Development on Unmanned Aerial Systems, RED-UAS, Linköping, Sweden, 3-5 October, 2017, Institute of Electrical and Electronics Engineers (IEEE), 2017Conference paper, Published paper (Refereed)
Abstract [en]

In this work, we estimate a model of the vertical dynamics of a quadcopter and explain how this model can be used for mass estimation and diagnosis of system changes. First, a standard thrust model describing the relation between the calculated control signals of the rotors and the thrust that is commonly used in literature is estimated. The estimation results are compared to those using a refined thrust model and it turns out that the refined model gives a significant improvement. The combination of a nonlinear model and closed-loop data poses some challenges and it is shown that an instrumental variables approach can be used to obtain accurate estimates. Furthermore, we show that the refined model opens up for fault detection of the quadcopter. More specifically, this model can be used for mass estimation and also for diagnosis of other parameters that might vary between and during missions.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2017
Keywords
payload, modeling, quadcopter, fault detection and isolation
National Category
Control Engineering
Identifiers
urn:nbn:se:liu:diva-141883 (URN)10.1109/RED-UAS.2017.8101665 (DOI)000427383700032 ()978-1-5386-0939-2 (ISBN)978-1-5386-0940-8 (ISBN)
Conference
Workshop on Research, Education and Development on Unmanned Aerial Systems, RED-UAS, Linköping, Sweden, 3-5 October, 2017
Projects
MarineUAS
Funder
EU, Horizon 2020, 642153
Note

This project has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No. 642153.

Available from: 2017-10-11 Created: 2017-10-11 Last updated: 2018-04-11Bibliographically approved
Linder, J., Enqvist, M., Fossen, T. I., Johansen, T. A. & Gustafsson, F. (2015). Modeling for IMU-based Online Estimation of a Ship's Mass and Center of Mass. Linköping: Linköping University Electronic Press
Open this publication in new window or tab >>Modeling for IMU-based Online Estimation of a Ship's Mass and Center of Mass
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2015 (English)Report (Other academic)
Abstract [en]

A ship's roll dynamics is very sensitive to changes in the loading conditions and a worst-case scenario is the loss of stability.  This paper proposes an approach for online estimation of a ship's mass and center of mass. Instead of focusing on a sensor-rich environment where all possible signals on a ship can be measured and a complete model of the ship can be estimated, a minimal approach is adopted. A model of the roll dynamics is derived from a well-established model in literature and it is assumed that only motion measurements from an inertial measurement unit together with measurements of the rudder angle are available. Furthermore, identifiability properties and disturbance characteristics of the model are presented. Due to the properties of the model, the parameters are estimated with an iterative instrumental variable approach to mitigate the influence of the disturbances and it uses multiple datasets simultaneously to overcome identifiability issues. Finally, a simulation study is presented to investigate the sensitivity to the initial conditions and it is shown that there is a low sensitivity for the desired parameters.

Place, publisher, year, edition, pages
Linköping: Linköping University Electronic Press, 2015. p. 16
Series
LiTH-ISY-R, ISSN 1400-3902 ; 3082
Keywords
modelling, identification, operational safety, inertial measurement unit, identifiability, centre of mass, physical models, accelerometers, gyroscopes, marine systems
National Category
Control Engineering
Identifiers
urn:nbn:se:liu:diva-115546 (URN)LiTH-ISY-R-3082 (ISRN)
Available from: 2015-03-16 Created: 2015-03-16 Last updated: 2015-03-24Bibliographically approved
Linder, J., Enqvist, M., Fossen, T. I., Johansen, T. A. & Gustafsson, F. (2015). Modeling for IMU-based Online Estimation of a Ship's Mass and Center of Mass. In: Proceedings of the 10th Conference on Manoeuvring and Control of Marine Craft: . Paper presented at 10th Conference on Manoeuvring and Control of Marine Craft.
Open this publication in new window or tab >>Modeling for IMU-based Online Estimation of a Ship's Mass and Center of Mass
Show others...
2015 (English)In: Proceedings of the 10th Conference on Manoeuvring and Control of Marine Craft, 2015, , p. 16Conference paper, Published paper (Refereed)
Abstract [en]

A ship's roll dynamics is very sensitive to changes in the loading conditions and a worst-case scenario is the loss of stability.  This paper proposes an approach for online estimation of a ship's mass and center of mass. Instead of focusing on a sensor-rich environment where all possible signals on a ship can be measured and a complete model of the ship can be estimated, a minimal approach is adopted. A model of the roll dynamics is derived from a well-established model in literature and it is assumed that only motion measurements from an inertial measurement unit together with measurements of the rudder angle are available. Furthermore, identifiability properties and disturbance characteristics of the model are presented. Due to the properties of the model, the parameters are estimated with an iterative instrumental variable approach to mitigate the influence of the disturbances and it uses multiple datasets simultaneously to overcome identifiability issues. Finally, a simulation study is presented to investigate the sensitivity to the initial conditions and it is shown that the sensitivity is low for the desired parameters.

Publisher
p. 16
Series
IFAC-PapersOnLine, ISSN 2405-8963 ; 48(16)
Keywords
modelling, identification, operational safety, inertial measurement unit, identifiability, centre of mass, physical models, accelerometers, gyroscopes, marine systems
National Category
Control Engineering
Identifiers
urn:nbn:se:liu:diva-120993 (URN)10.1016/j.ifacol.2015.10.280 (DOI)
Conference
10th Conference on Manoeuvring and Control of Marine Craft
Available from: 2015-09-01 Created: 2015-09-01 Last updated: 2016-06-22
Linder, J. & Enqvist, M. (2015). On Indirect Input Measurements.
Open this publication in new window or tab >>On Indirect Input Measurements
2015 (English)Report (Other academic)
Abstract [en]

A common issue with many system identification problems is that the true input to the system is unknown. In this paper, a framework, based on indirect input measurements, is proposed to solve the problem when the input is partially or fully unknown, and cannot be measured directly. The approach relies on measurements that indirectly contain information about the unknown input. The resulting indirect model formulation, with both direct- and indirect input measurements as inputs, can be used to estimate the desired model of the original system. Due to the similarities with closed-loop system identification, an iterative instrumental variable method is proposed to estimate the indirect model. To show the applicability of the proposed method, it is applied to data from an inverted pendulum experiment with good results.

Publisher
p. 16
Series
LiTH-ISY-R, ISSN 1400-3902 ; 3080
Keywords
System identification, Model structure, Physical models, Instrumental Variable, Closed-loop
National Category
Control Engineering
Identifiers
urn:nbn:se:liu:diva-115548 (URN)LiTH-ISY-R-3080 (ISRN)
Available from: 2015-03-16 Created: 2015-03-16 Last updated: 2015-03-24Bibliographically approved
Linder, J. & Enqvist, M. (2015). On Indirect Input Measurements. In: Proceedings of the 17th IFAC Symposium on System Identification: . Paper presented at 17th IFAC Symposium on System Identification, Beijing, China, October 19-21, 2015 (pp. 104-109).
Open this publication in new window or tab >>On Indirect Input Measurements
2015 (English)In: Proceedings of the 17th IFAC Symposium on System Identification, 2015, p. 104-109Conference paper, Published paper (Refereed)
Abstract [en]

A common issue with many system identification problems is that the true input to the system is unknown. In this paper, a framework, based on indirect input measurements, is proposed to solve the problem when the input is partially or fully unknown, and cannot be measured directly. The approach relies on measurements that indirectly contain information about the unknown input. The resulting indirect model formulation, with both direct and indirect input measurements as inputs, can be used to estimate the desired model of the original system. Due to the similarities with closed-loop system identification, an iterative instrumental variable method is proposed to estimate the indirect model. To show the applicability of the proposed method, it is applied to data from an inverted pendulum experiment with good results. 

Series
IFAC-PapersOnLine, ISSN 2405-8963 ; 48(28)
Keywords
System identification, Model structure, Physical models, Instrumental variable, Closed-loop
National Category
Control Engineering
Identifiers
urn:nbn:se:liu:diva-122291 (URN)10.1016/j.ifacol.2015.12.108 (DOI)
Conference
17th IFAC Symposium on System Identification, Beijing, China, October 19-21, 2015
Projects
LINK-SIC
Available from: 2015-10-28 Created: 2015-10-28 Last updated: 2016-06-22
Linder, J., Enqvist, M., Fossen, T. I., Johansen, T. A. & Gustafsson, F. (2015). Online Estimation of Ship's Mass and Center of Mass Using Inertial Measurements. Linköping: Linköping University Electronic Press
Open this publication in new window or tab >>Online Estimation of Ship's Mass and Center of Mass Using Inertial Measurements
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2015 (English)Report (Other academic)
Abstract [en]

A ship's roll dynamics is sensitive to the mass and mass distribution. Changes in these physical properties might introduce unpredictable behavior of the ship and a {worst-case} scenario is that the ship will capsize. In this paper, a recently proposed approach for online estimation of mass and center of mass is validated using experimental data. The experiments were performed using a scale model of a ship in a wave basin. The data was collected in free run experiments where the rudder angle was recorded and the ship's motion was measured using an inertial measurement unit. The motion measurements are used in conjunction with a model of the roll dynamics to estimate the desired properties. The estimator uses the rudder angle measurements together with an instrumental variable method to mitigate the influence of disturbances. The experimental study shows that the properties can be estimated with quite good accuracy but that variance and robustness properties can be improved further.

Place, publisher, year, edition, pages
Linköping: Linköping University Electronic Press, 2015. p. 16
Series
LiTH-ISY-R, ISSN 1400-3902 ; 3081
Keywords
modelling, identification, operational safety, inertial measurement unit, identifiability, centre of mass, physical models, accelerometers, gyroscopes, marine systems
National Category
Control Engineering
Identifiers
urn:nbn:se:liu:diva-115545 (URN)LiTH-ISY-R-3081 (ISRN)
Available from: 2015-03-16 Created: 2015-03-16 Last updated: 2015-03-24Bibliographically approved
Linder, J., Enqvist, M., Fossen, T. I., Johansen, T. A. & Gustafsson, F. (2015). Online Estimation of Ship's Mass and Center of Mass Using Inertial Measurements. In: Proceedings of the 10th Conference on Manoeuvring and Control of Marine Craft: . Paper presented at 10th Conference on Manoeuvring and Control of Marine Craft.
Open this publication in new window or tab >>Online Estimation of Ship's Mass and Center of Mass Using Inertial Measurements
Show others...
2015 (English)In: Proceedings of the 10th Conference on Manoeuvring and Control of Marine Craft, 2015, , p. 16Conference paper, Published paper (Refereed)
Abstract [en]

A ship's roll dynamics is sensitive to the mass and mass distribution. Changes in these physical properties might introduce unpredictable behavior of the ship and a worst-case scenario is that the ship will capsize. In this paper, a recently proposed approach for online estimation of mass and center of mass is validated using experimental data. The experiments were performed using a scale model of a ship in a wave basin. The data were collected in free run experiments where the rudder angle was recorded and the ship's motion was measured using an inertial measurement unit. The motion measurements are used in conjunction with a model of the roll dynamics to estimate the desired properties. The estimator uses the rudder angle measurements together with an instrumental variable method to mitigate the influence of disturbances. The experimental study shows that the properties can be estimated with quite good accuracy but that variance and robustness properties can be improved further.

Publisher
p. 16
Series
IFAC-PapersOnLine, ISSN 2405-8963 ; 48(16)
Keywords
modelling, identification, operational safety, inertial measurement unit, identifiability, centre of mass, physical models, accelerometers, gyroscopes, marine systems
National Category
Control Engineering
Identifiers
urn:nbn:se:liu:diva-120994 (URN)10.1016/j.ifacol.2015.10.270 (DOI)
Conference
10th Conference on Manoeuvring and Control of Marine Craft
Available from: 2015-09-01 Created: 2015-09-01 Last updated: 2016-06-22
Linder, J., Enqvist, M. & Gustafsson, F. (2014). A Closed-loop Instrumental Variable Approach to Mass and Center of Mass Estimation Using IMU Data. In: Proceedings of the 53rd Conference on Decision and Control: . Paper presented at 53rd Conference on Decision and Control, USA, Los Angeles, December 2014. (pp. 283-289).
Open this publication in new window or tab >>A Closed-loop Instrumental Variable Approach to Mass and Center of Mass Estimation Using IMU Data
2014 (English)In: Proceedings of the 53rd Conference on Decision and Control, 2014, p. 283-289Conference paper, Published paper (Refereed)
Abstract [en]

In this paper, an instrumental variable (IV) method for estimating the mass and center of mass (CM) of a ship using IMU data has been further investigated. Here, this IV method, which was proposed in an earlier paper, has been analyzed from a closed-loop point of view. This new perspective reveals the properties of the system and dependencies of the signals used in the estimation procedure. Due to similarities with closed-loop identification, previous results in the closed-loop identification field have been used as an inspiration to improve the IV estimator. Since the roll dynamics of a ship is well described by a pendulum model, a pendulum experiment has been carried out to validate the performance both of the original and the improved IV estimators. The experiments gave good results for the improved IV estimator with significantly lower variances and relative errors than the previous IV estimator.

National Category
Control Engineering
Identifiers
urn:nbn:se:liu:diva-117130 (URN)10.1109/CDC.2014.7039395 (DOI)978-1-4799-7746-8 (ISBN)
Conference
53rd Conference on Decision and Control, USA, Los Angeles, December 2014.
Projects
LINK-SIC
Available from: 2015-04-16 Created: 2015-04-16 Last updated: 2016-06-22
Jansson, A., Olsson, E., Linder, J. & Hjort, M. (2014). Developing of a Driver Model for Vehicle Testing. In: Proceedings of the 14th International Symposium on Advanced Vehicle Control (AVEC), Tokyo, September 2014: . Paper presented at 14th International Symposium on Advanced Vehicle Control (AVEC), Tokyo, September 22-26, 2014.
Open this publication in new window or tab >>Developing of a Driver Model for Vehicle Testing
2014 (English)In: Proceedings of the 14th International Symposium on Advanced Vehicle Control (AVEC), Tokyo, September 2014, 2014Conference paper, Published paper (Refereed)
Abstract [en]

There is today no established automated method for testing vehicles or tyres, and the most common option is using professional drivers for this purpose. The tests are supposed to be fair and repeatable, which means using human drivers for these kinds of vehicle testing is not an option. Using a steering robot modelled to drive as a human is therefore preferable. The approach described in this paper shows how a driver model can be created by using a control algorithm based on gathered data from human drivers performing double lane change (DLC) manoeuvres in a simulator. The implemented controller shows how human drivers’ behaviors can be captured using control theory.

National Category
Vehicle Engineering
Identifiers
urn:nbn:se:liu:diva-111129 (URN)
Conference
14th International Symposium on Advanced Vehicle Control (AVEC), Tokyo, September 22-26, 2014
Available from: 2014-09-18 Created: 2014-10-08 Last updated: 2016-02-05
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0003-3498-3204

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