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Mattsson, Per
Publications (7 of 7) Show all publications
Bai, S., Christensen, S., Islam, M., Rafique, S., Masud, N., Mattsson, P., . . . Power, V. (2019). Development and testing of full-body exoskeleton AXO-SUIT for physical assistance of the elderly. In: Maria Chiara Carrozza, Silvestro Micera, José L. Pons (Ed.), Wearable Robotics: Challenges and Trends: Proceedings of the 4th International Symposium on Wearable Robotics, WeRob2018, October 16-20, 2018, Pisa, Italy. Paper presented at 4th International Symposium on Wearable Robotics, WeRob2018, October 16-20, 2018, Pisa, Italy (pp. 180-184). Cham: Springer, 22
Open this publication in new window or tab >>Development and testing of full-body exoskeleton AXO-SUIT for physical assistance of the elderly
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2019 (English)In: Wearable Robotics: Challenges and Trends: Proceedings of the 4th International Symposium on Wearable Robotics, WeRob2018, October 16-20, 2018, Pisa, Italy / [ed] Maria Chiara Carrozza, Silvestro Micera, José L. Pons, Cham: Springer, 2019, Vol. 22, p. 180-184Conference paper, Published paper (Refereed)
Abstract [en]

This paper presents the design and preliminary testing of a full-body assistive exoskeleton AXO-SUIT for older adults. AXO-SUIT is a system of modular exoskeletons consisting of lower-body and upper-body modules, and their combination as full body as well to provide flexible physical assistance as needed. The full-body exoskeleton comprises 27 degrees of freedom, of which 17 are passive and 10 active, which is able to assist people in walking, standing, carrying and handling tasks. In the paper, design of the AXO-SUIT is described. End-user testing results are presented to show the effectiveness of the exoskeleton in providing flexible physical assistance.

Place, publisher, year, edition, pages
Cham: Springer, 2019
Series
Biosystems & Biorobotics (BIOSYSROB), ISSN 2195-3562, E-ISSN 2195-3570 ; 22
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:hig:diva-28664 (URN)10.1007/978-3-030-01887-0_35 (DOI)2-s2.0-85055055913 (Scopus ID)978-3-030-01886-3 (ISBN)978-3-030-01887-0 (ISBN)
Conference
4th International Symposium on Wearable Robotics, WeRob2018, October 16-20, 2018, Pisa, Italy
Funder
Vinnova, 2014-05953
Note

The work reported here is supported by the EU AAL Programme, Innovation Fund Denmark, Vinnova, Agentschap Innoveren & Ondernemen and Enterprise Ireland.

Available from: 2018-11-26 Created: 2018-11-26 Last updated: 2019-10-01Bibliographically approved
Mattsson, P., Zachariah, D. & Björsell, N. (2019). Flexible Models for Smart Maintenance. In: Proceedings 2019 IEEE International Conference on Industrial Technology (ICIT): . Paper presented at 20th IEEE International Conference on Industrial Technology (ICIT), 13-15 February 2019, Melbourne, Australia (pp. 1772-1777). IEEE
Open this publication in new window or tab >>Flexible Models for Smart Maintenance
2019 (English)In: Proceedings 2019 IEEE International Conference on Industrial Technology (ICIT), IEEE, 2019, p. 1772-1777Conference paper, Published paper (Refereed)
Abstract [en]

Smart maintenance strategies are becoming increasingly important in the industry, and can contribute to environmentally and economically sustainable production. In this paper a recently developed latent variable framework for nonlinear-system identification is considered for use in smart maintenance. A model is first identified using data from a system operating under normal conditions. Then the identified model is used to detect when the system begins to deviate from normal behavior. Furthermore, for systems that operate on separate batches (units), we develop a new method that identifies individual models for each batch. This can be used both to detect anomalous batches and changes in the system behavior. Finally, the two methods are evaluated on two different industrial case studies. In the first, the purpose is to detect fouling in a heat exchanger. In the second, the goal is to detect when the tool in a wood moulder machine should be changed.

Place, publisher, year, edition, pages
IEEE, 2019
Keywords
Applications, Modeling, Nonlinear systems
National Category
Robotics
Identifiers
urn:nbn:se:hig:diva-30445 (URN)10.1109/ICIT.2019.8754932 (DOI)10.1109/ICIT.2019.8754932 (Scopus ID)
Conference
20th IEEE International Conference on Industrial Technology (ICIT), 13-15 February 2019, Melbourne, Australia
Funder
Vinnova, 2017-04807Swedish Energy AgencySwedish Research Council FormasEuropean Regional Development Fund (ERDF)Swedish Agency for Economic and Regional Growth
Available from: 2019-07-22 Created: 2019-07-22 Last updated: 2019-10-04Bibliographically approved
Mattsson, P., Zachariah, D. & Stoica, P. (2018). Identification of cascade water tanks using a PWARX model.. Mechanical systems and signal processing, 106, 40-48
Open this publication in new window or tab >>Identification of cascade water tanks using a PWARX model.
2018 (English)In: Mechanical systems and signal processing, ISSN 0888-3270, E-ISSN 1096-1216, Vol. 106, p. 40-48Article in journal (Refereed) Published
Abstract [en]

In this paper we consider the identification of a discrete-time nonlinear dynamical model for a cascade water tank process. The proposed method starts with a nominal linear dynamical model of the system, and proceeds to model its prediction errors using a model that is piecewise affine in the data. As data is observed, the nominal model is refined into a piecewise ARX model which can capture a wide range of nonlinearities, such as the saturation in the cascade tanks. The proposed method uses a likelihood-based methodology which adaptively penalizes model complexity and directly leads to a computationally efficient implementation.

Keywords
DYNAMIC models, NONLINEAR theories, DISCRETE-time systems, LINEAR models (Statistics), TANKS, Nonlinear systems, Piecewise ARX models, System identification
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:hig:diva-26252 (URN)10.1016/j.ymssp.2017.12.027 (DOI)000426229100004 ()2-s2.0-85044843319 (Scopus ID)
Funder
Swedish Research Council, 621-2014-5874 2016-06079
Available from: 2018-03-20 Created: 2018-03-20 Last updated: 2018-06-04Bibliographically approved
Olsson, F., Halvorsen, K., Zachariah, D. & Mattsson, P. (2018). Identification of Nonlinear Feedback Mechanisms Operating in Closed Loop using Inertial Sensors. Paper presented at 18th IFAC Symposium on System Identification (SYSID), 9-11 July 2018, Stockholm, Sweden. IFAC-PapersOnLine, 51(15), 473-478
Open this publication in new window or tab >>Identification of Nonlinear Feedback Mechanisms Operating in Closed Loop using Inertial Sensors
2018 (English)In: IFAC-PapersOnLine, E-ISSN 2405-8963, Vol. 51, no 15, p. 473-478Article in journal (Refereed) Published
Abstract [en]

In this paper we study the problem of identifying linear and nonlinear feedback mechanisms, or controllers, operating in closed loop. A recently developed identification method for nonlinear systems, the LAVA method, is used for this purpose. Identification data is obtained from inertial sensors, that provide information about the movement of the system, in the form of linear acceleration and angular velocity measurements. This information is different from the information that is available to the controller to be identified, which makes use of unknown internal sensors instead. We provide two examples, a simulated neuromuscular controller in standing human balance, and a lead-filter controlling a physical position servo using a DC motor. Both linear and nonlinear controllers are used in the examples. We show that the LAVA method is able to identify sparse, parsimonious models of the controllers.

Place, publisher, year, edition, pages
Elsevier B.V., 2018
Keywords
Closed-loop identification, Inertial sensors, Nonlinear control, Controllers, DC motors, Feedback control, Inertial navigation systems, Closed loop identification, Feedback mechanisms, Identification method, Inertial sensor, Linear accelerations, Non linear control, Non-linear controllers, Parsimonious models, Nonlinear feedback
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:hig:diva-28645 (URN)10.1016/j.ifacol.2018.09.190 (DOI)000446599200081 ()2-s2.0-85054349996 (Scopus ID)
Conference
18th IFAC Symposium on System Identification (SYSID), 9-11 July 2018, Stockholm, Sweden
Projects
Mobile assessment of human balance
Funder
Swedish Research Council, 2015-05054
Available from: 2018-11-26 Created: 2018-11-26 Last updated: 2018-12-10Bibliographically approved
Medvedev, A., Mattsson, P., Zhusubaliyev, Z. T. & Avrutin, V. (2018). Nonlinear dynamics and entrainment in a continuously forced pulse-modulated model of testosterone regulation. Nonlinear dynamics, 94(2), 1165-1181
Open this publication in new window or tab >>Nonlinear dynamics and entrainment in a continuously forced pulse-modulated model of testosterone regulation
2018 (English)In: Nonlinear dynamics, ISSN 0924-090X, E-ISSN 1573-269X, Vol. 94, no 2, p. 1165-1181Article in journal (Refereed) Published
Abstract [en]

Dynamical behaviors arising in a previously developed pulse-modulated mathematical model of non-basal testosterone regulation in the human male due to continuous exogenous signals are studied. In the context of endocrine regulation, exogenous signals represent, e.g., the influx of a hormone replacement therapy drug, the influence of the circadian rhythm, and interactions with other endocrine loops. This extends the scope of the autonomous pulse-modulated models of endocrine regulation to a broader class of problems, such as therapy optimization, but also puts it in the context of biological rhythms studied in chronobiology. The model dynamics are hybrid since the hormone metabolism is suitably captured by a continuous description and the control feedback is implemented in a discrete (i.e., event-based) manner by the hypothalamus of the brain. It is demonstrated that the endocrine loop with an exogenous signal entering the continuous part can be equivalently described by proper modifications in the pulse modulation functions of the autonomous model. The cases of a constant and a harmonic exogenous signal are treated in detail and illustrated by the results of bifurcation analysis. According to the model, adding a constant exogenous signal only reduces the mean value of testosterone, which result pertains to the effects of hormone replacement therapies under intact endocrine feedback regulation. Further, for the case of a single-tone harmonic positive exogenous signal, bistability and quasiperiodicity arise in the system. The convergence to either of the stationary solutions in a bistable regime is shown to be controlled by the phase of the exogenous signal thus relating this transition to the phenomenon of jet lag.

Place, publisher, year, edition, pages
Springer Netherlands, 2018
Keywords
Biological oscillators, Chaotic and quasiperiodic dynamics, Circadian rhythm, Endocrine regulation, Entrainment regions, Hormone replacement therapies, Multistability, Pulse-modulated systems, Aviation medicine, Bifurcation (mathematics), Controlled drug delivery, Feedback, Fighter aircraft, Circadian rhythms, Hormone replacement therapy, Multi stabilities, Pulse modulated, Quasiperiodic dynamics, Dynamics
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:hig:diva-27516 (URN)10.1007/s11071-018-4416-6 (DOI)000445930300025 ()2-s2.0-85048784027 (Scopus ID)
Funder
Swedish Research Council, 2015-05256
Available from: 2018-07-04 Created: 2018-07-04 Last updated: 2018-11-23Bibliographically approved
Mattsson, P., Zachariah, D. & Stoica, P. (2018). Recursive nonlinear-system identification using latent variables. Automatica, 93, 343-351
Open this publication in new window or tab >>Recursive nonlinear-system identification using latent variables
2018 (English)In: Automatica, ISSN 0005-1098, E-ISSN 1873-2836, Vol. 93, p. 343-351Article in journal (Refereed) Published
Abstract [en]

In this paper we develop a method for learning nonlinear system models with multiple outputs and inputs. We begin by modeling the errors of a nominal predictor of the system using a latent variable framework. Then using the maximum likelihood principle we derive a criterion for learning the model. The resulting optimization problem is tackled using a majorization–minimization approach. Finally, we develop a convex majorization technique and show that it enables a recursive identification method. The method learns parsimonious predictive models and is tested on both synthetic and real nonlinear systems.

Keywords
Nonlinear systems, Multi-input/multi-output systems, System identification
National Category
Computer and Information Sciences
Identifiers
urn:nbn:se:hig:diva-27382 (URN)10.1016/j.automatica.2018.03.007 (DOI)000436916200036 ()2-s2.0-85054375676 (Scopus ID)
Funder
Swedish Research Council, 621-2014-5874Swedish Research Council, 2016-06079
Available from: 2018-06-25 Created: 2018-06-25 Last updated: 2018-12-05Bibliographically approved
Chistiakova, T., Mattsson, P., Carlsson, B. & Wigren, T. (2017). Nonlinear system identification of the dissolved oxygen to effluent ammonia dynamics in an activated sludge process. IFAC-PapersOnLine, 50(1), 3917-3922
Open this publication in new window or tab >>Nonlinear system identification of the dissolved oxygen to effluent ammonia dynamics in an activated sludge process
2017 (English)In: IFAC-PapersOnLine, ISSN 1045-0823, E-ISSN 1797-318X, Vol. 50, no 1, p. 3917-3922Article in journal (Refereed) Published
Abstract [en]

Aeration of biological reactors in wastewater treatment plants is important to obtain a high removal of soluble organic matter as well as for nitrification but requires a significant use of energy. It is hence of importance to control the aeration rate, for example, by ammonium feedback control. The goal of this paper is to model the dynamics from the set point of an existing dissolved oxygen controller to effluent ammonia using two types of system identification methods for a Hammerstein model, including a newly developed recursive variant. The models are estimated and evaluated using noise corrupted data from a complex mechanistic model (Activated Sludge Model no.1). The performance of the estimated nonlinear models are compared with an estimated linear model and it is shown that the nonlinear models give a significantly better fit to the data. The resulting models may be used for adaptive control (using the recursive Hammerstein variant), gain-scheduling control, L2 stability analysis, and model based fault detection.

Place, publisher, year, edition, pages
Elsevier B.V., 2017
Keywords
BSM1, Hammerstein model, Output error model, System identification, Wastewater treatment
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:hig:diva-25591 (URN)10.1016/j.ifacol.2017.08.365 (DOI)000423964800149 ()2-s2.0-85031818334 (Scopus ID)
Available from: 2017-11-24 Created: 2017-11-24 Last updated: 2018-06-04Bibliographically approved
Projects
Assistive exoskeleton suitable for elderly persons [2014-05953_Vinnova]; University of Gävle; Publications
Christensen, S., Bai, S., Rafique, S., Isaksson, M., O'Sullivan, L., Power, V. & Virk, G. S. (2019). AXO-SUIT: A Modular Full-Body Exoskeleton for Physical Assistance. In: Alessandro Gasparetto and Marco Ceccarelli (Ed.), Alessandro Gasparetto and Marco Ceccarelli (Ed.), Mechanism Design for Robotics: Proceedings of the 4th IFToMM Symposium on Mechanism Design for Robotics. Paper presented at MEDER: IFToMM Symposium on Mechanism Design for Robotics,11-13 September 2018, Udine, Italy (pp. 443-450). Paper presented at MEDER: IFToMM Symposium on Mechanism Design for Robotics,11-13 September 2018, Udine, Italy. Cham: Springer Netherlands, 66Bai, S., Christensen, S., Islam, M., Rafique, S., Masud, N., Mattsson, P., . . . Power, V. (2019). Development and testing of full-body exoskeleton AXO-SUIT for physical assistance of the elderly. In: Maria Chiara Carrozza, Silvestro Micera, José L. Pons (Ed.), Wearable Robotics: Challenges and Trends: Proceedings of the 4th International Symposium on Wearable Robotics, WeRob2018, October 16-20, 2018, Pisa, Italy. Paper presented at 4th International Symposium on Wearable Robotics, WeRob2018, October 16-20, 2018, Pisa, Italy (pp. 180-184). Cham: Springer, 22Krishnan, R., Björsell, N. & Smith, C. (2017). Segmenting humeral submovements using invariant geometric signatures. In: Bicchi, A., Okamura, A. (Ed.), 2017 IEEE/RSJ International Conference on Intelligent Robots and Systems (Iros): . Paper presented at 2017 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS 2017), 24–28 September 2017, Vancouver, Canada (pp. 6951-6958). IEEE, Article ID 8206619. Krishnan, R., Björsell, N. & Smith, C. (2016). Invariant Spatial Parametrization of Human Thoracohumeral Kinematics: A Feasibility Study. In: 2016 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS): . Paper presented at IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS 2016), 9-14 October 2016, Daejeon, Korea (pp. 4469-4476). IEEE Robotics and Automation Society, Article ID 7759658. Haider, U., Nyoman, I. I., Coronado, J. L., Kim, C. & Virk, G. S. (2016). User-centric Harmonized Control for Single Joint Assistive Exoskeletons. International Journal of Advanced Robotic Systems, 13(3), Article ID 115. O’Sullivan, L., Power, V., Virk, G. S., Masud, N., Haider, U., Christensen, S., . . . Voncke, K. (2015). End user needs elicitation for a full-body exoskeleton to assist the elderly. In: Ahram, T., Karwowski, W. and Schmorrow, D. (Ed.), 6TH International Conference on Applied Human Factors and Ergonomics (AHFE 2015) and the  affiliated conferences: . Paper presented at 6TH International Conference on Applied Human Factors and Ergonomics (AHFE 2015), 26-30 July 2015, Las Vegas, Neevada, USA (pp. 1403-1409). Amsterdam: Elsevier
Flexible Models for Smart Maintenance [2017-04807_Vinnova]; University of Gävle; Publications
Mattsson, P., Zachariah, D. & Björsell, N. (2019). Flexible Models for Smart Maintenance. In: Proceedings 2019 IEEE International Conference on Industrial Technology (ICIT): . Paper presented at 20th IEEE International Conference on Industrial Technology (ICIT), 13-15 February 2019, Melbourne, Australia (pp. 1772-1777). IEEE
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