Martin Marie Hubert Choux

• Økter, Martin Bjaadal; Brekke, Vegard; Dybdahl, Eirik; Tyapin, Ilya & Choux, Martin Marie Hubert (2026). A Robotic Setup for Adaptive EV-Battery Disassembly Using ROS2 in a Near-Industrial Environment. IEEE International Conference on System of Systems Engineering (SoSE). ISSN 2835-3307. doi: 10.1109/SoSE69681.2026.11622357. Fulltekst i vitenarkiv Vis sammendrag

  The growing number of end-of-life electric vehicle (EV) batteries demands scalable and adaptive disassembly solutions to enable efficient recycling. This paper presents a near-industrial robotic demonstrator for adaptive EV battery pack disassembly. The system integrates two industrial manipulators, force/torque sensing, automatic tool changing, and structured-light 3D vision within a ROS2-based perception and control architecture. A YOLO-based detection pipeline combined with point-cloud processing and coordinate transformation enables the automatic generation of robot targets for multi-step operations, including nut removal and battery module extraction. The results demonstrate that the modular integration of industrial robotics and AI-based perception can enable adaptive, multi-operation battery disassembly in a near-industrial environment. Experimental validation across 36 disassembly trials demonstrates reliable module extraction with a 100% success rate and an overall nut removal success rate of 77.6%, with performance degradation primarily linked to perception-localisation errors for off-axis nut detections.

• Økter, Martin Bjaadal; Tyapin, Ilya & Choux, Martin Marie Hubert (2025). Dynamic Robotic Disassembly using Reinforcement Learning and Simulation: Initial Application to EV Batteries. International Conference on Control, Mechatronics and Automation. ISSN 2837-5114. doi: 10.1109/iccma67641.2025.11369636. Fulltekst i vitenarkiv Vis sammendrag

  The disassembly of electric vehicle (EV) battery packs remains a labor-intensive and potentially hazardous process, complicated by significant variations in pack design and condition. Conventional automation relies on rigid programming and prior knowledge of component layout, which limits scalability and adaptability. This work presents a proof-of-concept framework for adaptive robotic disassembly using reinforcement learning (RL) and high-fidelity simulation. A simplified two-stage disassembly task—removing a locking pin from a pipe-and-cylinder assembly, was implemented in NVIDIA Isaac Sim and integrated with the Isaac Lab RL environment. Proximal Policy Optimization (PPO) agents were trained using both the RSL-RL and StableBaselines3 libraries, employing structured reward shaping, targeted hyperparameter tuning, and Cartesian end-effector control to improve learning stability and task precision. Initial results demonstrate consistent task completion, with reduced unintended movement of non-target components and high repeatability across validation runs. The developed simulation and training pipeline provides a flexible, modular platform for future exploration of alternative RL algorithms and more complex disassembly scenarios. These results highlight the potential of RL-based methods to enable scalable, dynamic automation for EV battery recycling in environments with high variability and uncertainty.

• Bilal, Muhammad Talha; Tian, Doris Siyu; Choux, Martin Marie Hubert; Jiao, Lei & Tyapin, Ilya (2025). Optimizing Automated Battery Demanufacturing Through Simulation-Based Analysis and Genetic Algorithm. Robotics. 14(11). doi: 10.3390/robotics14110156. Fulltekst i vitenarkiv Vis sammendrag

  The automation of recycling processes for electric vehicle lithium-ion battery packs is crucial for the advancement of green energy transportation. Testing disassembly strategies on real equipment is time consuming, expensive, and poses significant safety risks. This paper presents a novel simulation-based framework that leverages the integration of a high-fidelity virtual environment with a Robot Operating System (ROS) to visualize and accurately calculate the time required for complex robotic disassembly operations. The calculated operation times are then used as input for genetic algorithm optimization to improve process efficiency. The results demonstrate that automation significantly improves the total speed of the disassembly process compared to manual methods. By utilizing this novel simulation and optimization approach, a 25% improvement in performance was achieved for the pack-to-module disassembly stage. This method provides a safe and cost-effective approach for process design, contributing directly to the development of a circular economy and supporting the transition towards sustainable transportation.

• Choux, Martin Marie Hubert; Pripp, Simon Waldemar; Kvalnes, Frode & Hellström, Magnus Mikael (2024). To shred or to disassemble – A techno-economic assessment of automated disassembly vs. shredding in lithium-ion battery module recycling. Resources, Conservation and Recycling. ISSN 0921-3449. 203, s. 1–11. doi: 10.1016/j.resconrec.2024.107430. Fulltekst i vitenarkiv Vis sammendrag

  The global adoption of electric vehicles (EVs) is driving a surge in the use of lithium-ion batteries (LIBs), creating an urgent need for sophisticated recycling techniques to recover valuable materials and manage waste. Particularly, automating the laborintensive disassembly process is critical for scaling up recycling efforts. This study provides a techno-economic evaluation of a robotic line for disassembling EV LIB modules, exploring whether it's more profitable to extend automation to the cell level. Three different EV modules are examined, and several scenarios are proposed, showing that investments in robotic disassembly could be financially sound, particularly with the anticipated rise in end-of-life EV LIBs. The key to profitability lies in disassembling to the cell level, which enables the recovery of more valuable materials and reduces downstream processing requirements. This research offers practical guidelines for automating the disassembly process in line with future waste management demands.

• Bilal, Muhammad Talha; Tyapin, Ilya & Choux, Martin Marie Hubert (2023). Fusion of Multiview Images for EV Battery Disassembly. I Zhou, Jing (Red.), 2023 11th International Conference on Control, Mechatronics and Automation (ICCMA). IEEE (Institute of Electrical and Electronics Engineers). ISSN 9798350315684. s. 19–24. doi: 10.1109/ICCMA59762.2023.10374794. Fulltekst i vitenarkiv Vis sammendrag

  Automation in Electric Vehicle (EV) Li-Ion Battery (LIB) pack disassembly is getting a lot of attraction with increased number of EVs being manufactured. Highly cluttered components placed in complex configurations present a unique challenge for object detection models. To get maximum coverage of the components in the EV battery pack, images from multiple viewpoints are considered and merged using Multiple-View Super Resolution (MVSR). The proposed method provides 7% higher accuracy in the screw detection task than the statistical methods previously derived [[1]].

• Szabo, Vera; Ebrahimi, Saeed Hasan; Choux, Martin Marie Hubert & Goodwin, Morten (2022). ITSC Fault Diagnosis in Permanent Magnet Synchronous Motor Drives Using Shallow CNNs. I Boracchi, Giacomo; Iliadis, Lazaros; Jayne, Chrisina & Likas, Aristidis (Red.), Engineering Applications of Neural Networks - 18th International Conference, EANN 2017. Springer. ISSN 9783319651712. s. 177–189. doi: 10.1007/978-3-031-08223-8_15. Fulltekst i vitenarkiv Vis sammendrag

  Due to its features, permanent magnet synchronous motor (PMSM) has gained popularity and is used in various industrial applications, including those with high downtime costs like offshore equipment. Inter-turn short-circuit (ITSC) fault is one of the most typical PMSM faults and therefore is its early diagnostics in real-time highly valuable. Solving the problem using conventional signal, model-based, or data-driven approaches faces challenges such as computational complexity, time demand, or need for detailed domain expertise. This paper presents a computationally simple, robust, and accurate method based on the 2D convolutional neural network (CNN). The proposed data-driven model has first been validated with the help of experimental data obtained from an inverter fed PMSM subject to ITSC faults in different time intervals, and secondly its performances have been compared to a model-based structural analysis approach using Dulmage-Mendelsohn decomposition tool. The comparison is based on the same data. Results show that the accuracy of the CNN model for diagnosing early faults is more than 98% without doing additional comprehensive fine-tuning. In addition, the paper presents a robust method that can be successfully used as a metric for fast fault detection benchmark.

• Ebrahimi, Saeed Hasan; Choux, Martin Marie Hubert & Huynh, Khang (2022). Real-Time Detection of Incipient Inter-Turn Short Circuit and Sensor Faults in Permanent Magnet Synchronous Motor Drives Based on Generalized Likelihood Ratio Test and Structural Analysis. Sensors. 22(9). doi: 10.3390/s22093407. Fulltekst i vitenarkiv Vis sammendrag

  This paper presents a robust model-based technique to detect multiple faults in permanent magnet synchronous motors (PMSMs), namely inter-turn short circuit (ITSC) and encoder faults. The proposed model is based on a structural analysis, which uses the dynamic mathematical model of a PMSM in an abc frame to evaluate the system’s structural model in matrix form. The just-determined and over-determined parts of the system are separated by a Dulmage–Mendelsohn decomposition tool. Subsequently, the analytical redundant relations obtained using the over-determined part of the system are used to form smaller redundant testable sub-models based on the number of defined fault terms. Furthermore, four structured residuals are designed based on the acquired redundant sub-models to detect measurement faults in the encoder and ITSC faults, which are applied in different levels of each phase winding. The effectiveness of the proposed detection method is validated by an in-house test setup of an inverter-fed PMSM, where ITSC and encoder faults are applied to the system in different time intervals using controllable relays. Finally, a statistical detector, namely a generalized likelihood ratio test algorithm, is implemented in the decision-making diagnostic system resulting in the ability to detect ITSC faults as small as one single short-circuited turn out of 102, i.e., when less than 1% of the PMSM phase winding is short-circuited.

• Brådland, Henrik; Choux, Martin Marie Hubert & Cenkeramaddi, Linga Reddy (2022). Point Cloud Instance Segmentation for Automatic Electric Vehicle Battery Disassembly. I Sanfilippo, Filippo; Granmo, Ole-Christoffer; Yayilgan, Sule Yildirim & Bajwa, Imran Sarwar (Red.), Intelligent Technologies and Applications: 4th International Conference, INTAP 2021, Grimstad, Norway, October 11–13, 2021, Revised Selected Papers. Springer. ISSN 9783031105241. s. 247–258. doi: 10.1007/978-3-031-10525-8_20. Fulltekst i vitenarkiv Vis sammendrag

  This paper describes a novel design based on recent 3D perception methods for capturing point clouds and segmenting instances of cabling found on electric vehicle battery packs. The use of cutting-edge perception algorithm architectures, such as graph-based and voxel-based convolution, in industrial autonomous lithium-ion battery pack disassembly is investigated. The proposed approach focuses on the challenge of getting a desirable representation of any battery pack using an industrial robot in conjunction with a high-end structured light camera, with “end-to-end” and “model-free” as design constraints. The proposed design employs self-captured datasets comprised of several battery packs that have been captured and labeled. Following that, the datasets are used to create a perception system. Based on the results, graph-based deep-learning algorithms have been shown to be capable of being scaled up to 50, 000 inputs while still exhibiting strong performance in terms of accuracy and processing time. The results show that an instance segmenting system can be implemented in less than two seconds. Using off-the-shelf hardware, we demonstrate that a 3D perception system is industrially viable and competitive as compared to a 2D perception system (The different algorithms studied in this article are implemented in Python and can be obtained through the following link: https://github.com/HenrikBradland-Nor/intap21).

• Bilal, Muhammad Talha; Tyapin, Ilya & Choux, Martin Marie Hubert (2022). Enhancing Object Localization Accuracy by using Multiple Camera Viewpoints for Disassembly Systems, IECON 2022 – 48th Annual Conference of the IEEE Industrial Electronics Society. IEEE (Institute of Electrical and Electronics Engineers). ISSN 9781665480253. doi: 10.1109/IECON49645.2022.9968575. Fulltekst i vitenarkiv Vis sammendrag

  The number of images taken from different view-points plays an important role in the accuracy of object detection in cluttered scenarios. Considering Electric Vehicles battery pack disassembly task, which is a highly dense clutter, a framework is proposed to approximate the number of viewpoints to acquire the accuracy of 3.82 mm in screw detection. The paper explores two methods of image acquisition i) taking multiple 3D images, and ii) taking one 3D image and multiple 2D images and combines it with two methods of image processing i) marking the exact visible center of the screw for calculation, and ii) using a bounding box to mark the screw and calculating the center by intersecting diagonals. The results show that using eight viewpoints with a reliable 3D camera delivers the optimal results.

• Ebrahimi, Saeed Hasan; Choux, Martin Marie Hubert & Huynh, Khang (2021). Detection and Discrimination of Inter-Turn Short Circuit and Demagnetization Faults in PMSMs Based on Structural Analysis, 22nd IEEE International Conference on Industrial Technology (ICIT). IEEE (Institute of Electrical and Electronics Engineers). ISSN 9781728157306. s. 184–189. doi: 10.1109/ICIT46573.2021.9453557. Fulltekst i vitenarkiv Vis sammendrag

  This paper presents a fault diagnosis method based on structural analysis of permanent magnet synchronous motors (PMSMs), focusing on detecting and discriminating two of the most common faults in PMSMs, namely demagnetization and inter-turn short circuit faults. The structural analysis technique uses the dynamic mathematical model of the PMSM in matrix form to evaluate the system’s structural model. After obtaining the analytical redundancy using the over-determined part of the system, it is divided into redundant testable sub-models. Four structured residuals are designed to detect and isolate the investigated faults, which are applied to the system in different time intervals. Finally, the proposed diagnostic approach is numerically verified through a simulation of an inverter-fed PMSM and white Gaussian noise are added to the measured signals from the motor to verify its diagnosis performances.

• Ebrahimi, Saeed Hasan; Choux, Martin Marie Hubert & Huynh, Khang (2021). Diagnosis of Sensor Faults in PMSM and Drive System Based on Structural Analysis, 2021 IEEE International Conference on Mechatronics (ICM). IEEE (Institute of Electrical and Electronics Engineers). ISSN 9781728144436. doi: 10.1109/ICM46511.2021.9385663. Fulltekst i vitenarkiv Vis sammendrag

  Virtual reality promises to be a tool that can improve higher education. Immersive virtual environments offer the chance to enrich courses with experiential learning experiences. The technological possibilities evolve rapidly and more and more researchers report on adopting virtual reality for learning – albeit such work often has a more or less experimental character. However, the base of knowledge on using virtual reality in higher education is growing; educators who want to employ virtual reality to amend courses, to extend the curriculum with experiential learning, or who want to offer new content enabled through virtual reality, find increasingly rich advice. With this article, we contribute to this advice by providing insights from three research cases. Although these were experimental, their embedding into a larger project enables us to propose recommendations for educators. The ultimate aim of our work is the routine use of virtual reality in higher education.

• Choux, Martin Marie Hubert; Bigorra, Eduard Marti & Tyapin, Ilya (2021). Task Planner for Robotic Disassembly of Electric Vehicle Battery Pack. Metals. 11(3). doi: 10.3390/met11030387. Fulltekst i vitenarkiv
• Hagen, Daniel; Padovani, Damiano & Choux, Martin Marie Hubert (2020). Guidelines to Select Between Self-Contained Electro-Hydraulic and Electro-Mechanical Cylinders, 15th IEEE Conference on Industrial Electronics and Applications. Institute of Electrical and Electronics Engineers (IEEE). ISSN 9781728151687. s. 547–554. doi: 10.1109/ICIEA48937.2020.9248373. Fulltekst i vitenarkiv
• Golzar, Milad; Kandukuri, Surya Teja; Huynh, Khang; Choux, Martin Marie Hubert & Versland, Alf Magne (2020). A Novel Fault Indicator for Local Demagnetization in Fractional-Slot Permanent Magnet Synchronous Motor using Winding Function Theory. Proceedings of the European Conference of the Prognostics and Health Management Society (PHME). Fulltekst i vitenarkiv Vis sammendrag

  Local demagnetization is an irreparable failure mode in permanent magnet synchronous motors (PMSMs), resulting in reduced motor efficiency and high cogging torque. These effects are particularly disadvantageous to fractional-slot wound PMSMs used in industrial applications, such as robotics and automations, that require high power density and precise operation. In this article, a diagnostic indicator is developed for detecting local demagnetization fault in fractional-slot wound PMSMs based on winding function theory, utilizing back-electromotive force (back-EMF) as a medium for fault detection. Further, the developed indicator is validated in a commercial fractional-slot wound PMSM of an in-house experimental setup.

• Ebrahimi, Saeed Hasan; Choux, Martin Marie Hubert & Huynh, Khang (2020). Modeling Stator Winding Inter-Turn Short Circuit Faults in PMSMs including Cross Effects. I Liu, Yujing (Red.), Proc. 2020 International Conference on Electrical Machines (ICEM). IEEE (Institute of Electrical and Electronics Engineers). ISSN 9781728199450. doi: 10.1109/ICEM49940.2020.9270890. Fulltekst i vitenarkiv Vis sammendrag

  This paper presents a detailed analysis of stator winding inter-turn Short Circuit (ITSC) faults, taking the cross effects in the three phases of a permanent magnet synchronous motor (PMSM) into account by considering insulation degradation resistances. A PMSM with series coils in each phase winding is selected as a case study.The ITSC in one coil of each phase winding is modelled based on deformed fluxes or inductance variations caused by flux linkages, depending on the distribution of the coils in the same phase winding. Different fault ratios are investigated to evaluate different fault severity and scenarios. Therefore, three-phase faulty coils within three-phase winding analysis dynamics will constitute sixth-order assessments. The proposed faulty PMSM model is verified by a 2-D finite element analysis (FEA), showing show a good agreement between the proposed model and FEA.

• Golzar, Milad; Huynh, Khang; Choux, Martin Marie Hubert & Versland, Alf Magne Midtbø (2019). Experimental Investigation of Efficiency Map for an Inverter-Fed Surface-Mount Permanent Magnet Synchronous Motor, 2019 8th International Conference on Renewable Energy Research and Applications (ICRERA). IEEE (Institute of Electrical and Electronics Engineers). ISSN 9781728135878. doi: 10.1109/ICRERA47325.2019.8996549. Fulltekst i vitenarkiv
• Hagen, Daniel; Padovani, Damiano & Choux, Martin Marie Hubert (2019). A Comparison Study of a Novel Self-Contained Electro-Hydraulic Cylinder versus a Conventional Valve-Controlled Actuator—Part 2: Energy Efficiency. Actuators. 8(4). doi: 10.3390/ACT8040078. Fulltekst i vitenarkiv
• Hagen, Daniel; Padovani, Damiano & Choux, Martin Marie Hubert (2019). A Comparison Study of a Novel Self-Contained Electro-Hydraulic Cylinder versus a Conventional Valve-Controlled Actuator—Part 1: Motion Control. Actuators. 8(4). doi: 10.3390/ACT8040079. Fulltekst i vitenarkiv
• Hagen, Daniel; Padovani, Damiano & Choux, Martin Marie Hubert (2019). Design and Implementation of Pressure Feedback for Load-Carrying Applications with Position Control. I Huhtala, Kalevi; Tikkanen, Seppo & Uusi-Heikkilä, Janne (Red.), The Sixteenth Scandinavian International Conference on Fluid Power, SICFP19: Proceedings. Tampere University of Technology. ISSN 9789520313029. s. 520–534. Fulltekst i vitenarkiv Vis sammendrag

  This research paper presents the design and implementation of pressure feedback on a hydraulically actuated single-boom crane operated in closed-loop position control. It is well known that systems with pressure compensated proportional valves in combination with over-center valves tend to induce instability, especially when the external load is overrunning (e.g., while lowering a load). However, in some applications pressure oscillations arise also with resistant external loads (e.g., while lifting a load). Hence, a pressure feedback capable of stabilizing the system functioning in both operations using the pressures from both actuator chambers (i.e., piston-side and rod-side) is proposed and compared against the conventional solution using only the rod-side chamber pressure. The investigation demonstrates that the implementation of a proposed “inverse valve dynamic” algorithm is needed in order for the control valve to stabilize the system when introducing the piston-side pressure in the pressure feedback. With this new method, the experimental tests demonstrate a satisfactory reduction of the pressure fluctuations in closed-loop motion control and a good position tracking (the average position error while lowering the load is reduced by almost 90% compared to the original system without pressure feedback). Finally, simulated results show that the proposed pressure feedback allows for potential energy savings of about 50% when lowering the load.

• Hagen, Daniel; Padovani, Damiano & Choux, Martin Marie Hubert (2019). Enabling Energy Savings in Offshore Mechatronic Systems by using Self-Contained Cylinders. MIC Journal: Modeling, Identification and Control. ISSN 0332-7353. 40(2), s. 89–108. doi: 10.4173/mic.2019.2.2. Fulltekst i vitenarkiv
• Pawlus, Witold; Kandukuri, Surya Teja; Hovland, Geir; Choux, Martin Marie Hubert & Hansen, Michael Rygaard (2016). EKF-based estimation and control of electric drivetrain in offshore pipe racking machine, 2016 IEEE International Conference on Industrial Technology (ICIT). IEEE (Institute of Electrical and Electronics Engineers). ISSN 9781467380751. s. 153–158. doi: 10.1109/ICIT.2016.7474742. Fulltekst i vitenarkiv
• Pawlus, Witold; Choux, Martin Marie Hubert & Hansen, Michael Rygaard (2016). Hydraulic vs. electric: A review of actuation systems in offshore drilling equipment. MIC Journal: Modeling, Identification and Control. ISSN 0332-7353. 37(1), s. 1–17. doi: 10.4173/mic.2016.1.1. Fulltekst i vitenarkiv
• Pawlus, Witold; Ebbesen, Morten Kjeld; Hansen, Michael Rygaard; Choux, Martin Marie Hubert & Hovland, Geir (2016). Comparative analysis of numerical models of pipe handling equipment used in offshore drilling applications. AIP Conference Proceedings. ISSN 0094-243X. 1738. doi: 10.1063/1.4952158. Fulltekst i vitenarkiv
• Pawlus, Witold; Choux, Martin Marie Hubert; Hansen, Michael Rygaard & Hovland, Geir (2016). Load torque estimation method to design electric drivetrains for offshore pipe handling equipment. Journal of Offshore Mechanics and Arctic Engineering. ISSN 0892-7219. 138(4). doi: 10.1115/1.4032897. Fulltekst i vitenarkiv
• Pawlus, Witold; Hansen, Michael Rygaard; Choux, Martin Marie Hubert & Hovland, Geir (2016). Mitigation of Fatigue Damage and Vibration Severity of Electric Drivetrains by Systematic Selection of Motion Profiles. IEEE/ASME transactions on mechatronics. ISSN 1083-4435. 21(6), s. 2870–2880. doi: 10.1109/TMECH.2016.2573587. Fulltekst i vitenarkiv
• Pawlus, Witold; Hansen, Michael Rygaard; Hovland, Geir & Choux, Martin Marie Hubert (2015). Torque Peak Reduction and Overload Monitoring of Induction Motors in Offshore Drilling Operations, ACEMP 2015 Optim - Electromotion Joint Conference. IEEE Press. ISSN 9781467372404. s. 393–398. doi: 10.1109/OPTIM.2015.7426962. Fulltekst i vitenarkiv
• Pawlus, Witold; Frick, Damian; Morari, Manfred; Hovland, Geir & Choux, Martin Marie Hubert (2015). Drivetrain Design Optimization for Electrically Actuated Systems via Mixed Integer Programing, Proceedings IECON 2015 - 41st Annual Conference of the IEEE Industrial Electronics Society. IEEE (Institute of Electrical and Electronics Engineers). ISSN 9781479917617. s. 1465–1470. doi: 10.1109/IECON.2015.7392307. Fulltekst i vitenarkiv
• Pawlus, Witold; Choux, Martin Marie Hubert; Hovland, Geir; Hansen, Michael Rygaard & Søren, Øydna (2014). Modeling and Simulation of An Offshore Pipe Handling Machine. I Kolaei, Alireza Rezania (Red.), The 55th Conference on Simulation and Modelling (SIMS 55) Proceedings. Linköping Electronic Conference Proceedings. ISSN 9789175193762. s. 277–284. doi: 10.1063/1.4952158. Fulltekst i vitenarkiv
• Pawlus, Witold Pawel; Choux, Martin Marie Hubert; Hovland, Geir & Huynh, Khang (2014). Parameters Identification of Induction Motor Dynamic Model for Offshore Applications, 2014 IEEE/ASME 10th International Conference on Mechatronic and Embedded Systems and Applications(MESA). IEEE (Institute of Electrical and Electronics Engineers). ISSN 9781479922802. doi: 10.1109/MESA.2014.6935555. Fulltekst i vitenarkiv
• Haaø, Jørgen; Vangen, Steffen; Tyapin, Ilya; Choux, Martin Marie Hubert; Hovland, Geir & Hansen, Michael Rygaard (2012). The Effect of Friction in Passive and Active Heave Compensation of Crown Block Mounted Compensators. I Imsland, Lars Struen (Red.), 2012 IFAC Workshop on Automatic Control in Offshore Oil and Gas Production : Norwegian University of Science and Technology 31.5-1.6 2012. Elsevier. ISSN 9783902661999. doi: 10.3182/20120531-2-no-4020.00040. Fulltekst i vitenarkiv Vis sammendrag

  This paper studies the effects of friction model during passive and active heave compensation of offshore drilling equipment. The main purpose of heave compensation while drilling from vessels or semi-submersible platforms is to maintain the drilling operation unaffected by the wave induced motion. The investigated system is of an existing crown mounted compensator. A model of the system is developed which includes mechanics, hydraulics and pneumatics. The passive heave compensation scheme is described including force equalising hydraulic cylinders. In this paper the detrimental effect of friction on the heave compensation performance in both passive and active heave compensation is investigated and discussed.

• Choux, Martin Marie Hubert; Tyapin, Ilya & Hovland, Geir (2012). Leakage-detection in blade pitch control systems for wind turbines, Reliability and Maintainability Symposium (RAMS), 2012 Proceedings. IEEE (Institute of Electrical and Electronics Engineers). ISSN 9781457718519. doi: 10.1109/rams.2012.6175515. Fulltekst i vitenarkiv Vis sammendrag

  The main contribution of the work is a systematic study evaluating the performance of different filters for leakage detection in pitch control systems. The effectiveness of the proposed methods is examined in a Matlab/Simulink real-time environment. The test bed consists of the following elements: hydraulic power unit, servo valve, two leakage bypasses, hydraulic cylinder, payload and xPC-based control system. The filters are tested with the state-augmentation and the hypothesis testing approaches. To our knowledge, the comparison of these different approaches has not been done previously for this type of application. The paper concludes on the accuracy and sensitivity of the leakage detection as well as the computational complexity and the real-time performance.

• Choux, Martin Marie Hubert; Hovland, Geir & Blanke, Mogens (2012). Cascade Controller Including Backstepping for Hydraulic-Mechanical Systems. I Imsland, Lars Struen (Red.), 2012 IFAC Workshop on Automatic Control in Offshore Oil and Gas Production : Norwegian University of Science and Technology 31.5-1.6 2012. Elsevier. ISSN 9783902661999. doi: 10.3182/20120531-2-no-4020.00046. Fulltekst i vitenarkiv Vis sammendrag

  Development of a cascade controller structure including adaptive backstepping for a nonlinear hydraulic-mechanical system is considered in this paper where a dynamic friction (LuGre) model is included to obtain the necessary accuracy. The paper compares the performance of two variants of an adaptive backstepping tracking controller with earlier results. The new control architecture is analysed and enhanced tracking performance is demonstrated when including the extended friction model. The complexity of the backstepping procedure is significantly reduced due to the cascade structure. Hence, the proposed control structure is better suited to real-time implementation.

• Choux, Martin Marie Hubert; Tyapin, Ilya & Hovland, Geir (2012). Extended friction model of a hydraulic actuated system, Reliability and Maintainability Symposium (RAMS), 2012 Proceedings. IEEE (Institute of Electrical and Electronics Engineers). ISSN 9781457718519. doi: 10.1109/rams.2012.6175517. Fulltekst i vitenarkiv Vis sammendrag

  The main contribution of this paper is an experimental validation and comparison of three different friction models for an electro-hydraulic servo system. The first is the wellknown LuGre model which incorporates dynamic friction effects. The second model is based on a relatively recent publication by Yanada in 2008 [6], which incorporates liquid film thickness in the servo valve. The third model is a new contribution presented in this paper, where valve underlap and mass acceleration are combined with the LuGre model. The experimental results show that for hydraulic systems, the film thickness model is an improvement over the LuGre model, while the new model presented in this paper is an improvement over both the LuGre and the film thickness models. An accurate friction model is an important tool for reliability engineers when distinguishing maintenance related degradation from dynamic effects.

• Choux, Martin Marie Hubert & Blanke, Mogens (2011). Fault Diagnosis for Nonlinear Hydraulic-Mechanical Drilling Pipe Handling System, Proceedings of the 50th IEEE Conference on Decision and Control and European Control Conference (CDC-ECC 2011). IEEE (Institute of Electrical and Electronics Engineers). ISSN 9781612847993. s. 1620–1626. doi: 10.1109/cdc.2011.6161363. Fulltekst i vitenarkiv Vis sammendrag

  Leakage and increased friction are common faults in hydraulic cylinders that can have serious consequences if they are not detected at early stage. In this paper, the design of a fault detector for a nonlinear hydraulic mechanical system is presented. By considering the system in steady state, two residual signals are generated and analysed with a composite hypothesis test which accommodates for unknown parameters. T he resulting detector is able to detect abrupt changes in leakage or friction given the noisy pressure and position measurements. Test rig measurements validate the properties of residuals and high fidelity simulation and experimental results demonstrate the performance and feasibility of the proposed method.

• Choux, Martin Marie Hubert & Hovland, Geir (2010). Adaptive Backstepping Control of Nonlinear Hydraulic-Mechanical System Including Valve Dynamics. MIC Journal: Modeling, Identification and Control. ISSN 0332-7353. 31(1), s. 35–44. doi: 10.4173/mic.2010.1.3. Fulltekst i vitenarkiv Vis sammendrag

  The main contribution of the paper is the development of an adaptive backstepping controller for a nonlinear hydraulic-mechanical system considering valve dynamics. The paper also compares the performance of two variants of an adaptive backstepping tracking controller with a simple PI controller. The results show that the backstepping controller considering valve dynamics achieves significantly better tracking performance than the PI controller, while handling uncertain parameters related to internal leakage, friction, the orifice equation and oil characteristics.

Se alle arbeider i NVA

• Szabo, Vera; Ebrahimi, Saeed Hasan; Choux, Martin Marie Hubert & Goodwin, Morten (2022). ITSC Fault Diagnosis in Permanent Magnet Synchronous Motor Drives Using Shallow CNNs. Fulltekst i vitenarkiv
• Brådland, Henrik; Choux, Martin Marie Hubert & Cenkeramaddi, Linga Reddy (2021). Point Cloud Instance Segmentation for Automatic Electric Vehicle Battery Disassembly. Fulltekst i vitenarkiv
• Choux, Martin Marie Hubert (2019). Towards Automatic Disassembly of EV-batteries. Fulltekst i vitenarkiv
• Fässler, Bernhard; Choux, Martin Marie Hubert & Wrålsen, Benedikte (2019). Trailblazing Resource Management Through the Upcoming Battery Wave. Fulltekst i vitenarkiv
• Wrålsen, Benedikte; Fässler, Bernhard; Choux, Martin Marie Hubert & Wrålsen, Benedikte (2019). Batterier og sirkulær økonomi - forskning ved UiA. Fulltekst i vitenarkiv
• Choux, Martin Marie Hubert (2018). New Trends in Mechatronics. Fulltekst i vitenarkiv
• Robbersmyr, Kjell Gunnar; Choux, Martin Marie Hubert; Zhou, Jing & Knausgård, Kristian Muri (2018). Mekatronikk. Fulltekst i vitenarkiv
• Pawlus, Witold; Hansen, Michael Rygaard; Hovland, Geir & Choux, Martin Marie Hubert (2015). Torque Peak Reduction and Overload Monitoring of Induction Motors in Offshore Drilling Operations. Fulltekst i vitenarkiv
• Pawlus, Witold; Frick, Damian; Morari, Manfred; Hovland, Geir & Choux, Martin Marie Hubert (2015). Drivetrain Design Optimization for Electrically Actuated Systems via Mixed Integer Programing. Fulltekst i vitenarkiv
• Pawlus, Witold; Ebbesen, Morten Kjeld; Hansen, Michael Rygaard; Choux, Martin Marie Hubert & Hovland, Geir (2015). Comparative Analysis of Numerical Models of Pipe Handling Equipment Used in Offshore Drilling Applications. Fulltekst i vitenarkiv
• Ebrahimi, Saeed Hasan; Choux, Martin Marie Hubert & Huynh, Khang (2023). Real-Time Fault Diagnosis of Permanent Magnet Synchronous Motor and Drive System. Universitetet i Agder. ISSN 9788284271293. Fulltekst i vitenarkiv Vis sammendrag

  Permanent Magnet Synchronous Motors (PMSMs) have gained massive popularity in industrial applications such as electric vehicles, robotic systems, and offshore industries due to their merits of efficiency, power density, and controllability. PMSMs working in such applications are constantly exposed to electrical, thermal, and mechanical stresses, resulting in different faults such as electrical, mechanical, and magnetic faults. These faults may lead to efficiency reduction, excessive heat, and even catastrophic system breakdown if not diagnosed in time. Therefore, developing methods for real-time condition monitoring and detection of faults at early stages can substantially lower maintenance costs, downtime of the system, and productivity loss. In this dissertation, condition monitoring and detection of the three most common faults in PMSMs and drive systems, namely inter-turn short circuit, demagnetization, and sensor faults are studied. First, modeling and detection of inter-turn short circuit fault is investigated by proposing one FEM-based model, and one analytical model. In these two models, efforts are made to extract either fault indicators or adjustments for being used in combination with more complex detection methods. Subsequently, a systematic fault diagnosis of PMSM and drive system containing multiple faults based on structural analysis is presented. After implementing structural analysis and obtaining the redundant part of the PMSM and drive system, several sequential residuals are designed and implemented based on the fault terms that appear in each of the redundant sets to detect and isolate the studied faults which are applied at different time intervals. Finally, real-time detection of faults in PMSMs and drive systems by using a powerful statistical signal-processing detector such as generalized likelihood ratio test is investigated. By using generalized likelihood ratio test, a threshold was obtained based on choosing the probability of a false alarm and the probability of detection for each detector based on which decision was made to indicate the presence of the studied faults. To improve the detection and recovery delay time, a recursive cumulative GLRT with an adaptive threshold algorithm is implemented. As a result, a more processed fault indicator is achieved by this recursive algorithm that is compared to an arbitrary threshold, and a decision is made in real-time performance. The experimental results show that the statistical detector is able to efficiently detect all the unexpected faults in the presence of unknown noise and without experiencing any false alarm, proving the effectiveness of this diagnostic approach.

• Brådland, Henrik; SØRENSEN, IVER; Cenkeramaddi, Linga Reddy & Choux, Martin Marie Hubert (2021). Using AI and Robotics for EV battery cable detection. Universitetet i Agder. Fulltekst i vitenarkiv

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