Kim Mathiassen

• Sajadi, Seyedmohammadreza; Tariverdi, Abbas; Brun, Henrik; Elle, Ole Jakob & Mathiassen, Kim (2026). Robotic transesophageal echocardiography: system design and deep learning-based kinematic modeling. Frontiers in Robotics and AI. 12. doi: 10.3389/frobt.2025.1705142. Full text in Research Archive
• Nygaard, Tønnes; Tiderko, Alexander; Schneider, Frank E.; Bounker, Paul; Glówka, Jakub & Nielsen, Niels Hygum [Show all 8 contributors for this article] (2025). Interoperability for Semi-Autonomous Unmanned Ground Vehicles, 2025 International Conference on Military Communication and Information Systems (ICMCIS). IEEE (Institute of Electrical and Electronics Engineers). ISSN 9798331537869. doi: 10.1109/icmcis64378.2025.11047908. Full text in Research Archive Show summary

  This paper describes the NATO STO IST-179-RTG group's efforts to improve interoperability of semiautonomous unmanned ground vehicles. Through experiments and demonstrations at major events like the European Robotics Hackathon 2021 and the European Land-Robot Trial 2022, a practical application of interoperability standards was investigated in different real-world scenarios, demonstrating both current capabilities and potential areas of improvement. This paper was originally presented at the NATO Science and Technology Organization Symposium (ICMCIS) organized by the Information Systems Technology (IST) Panel, IST-209-RSY - the ICMCIS, held in Oeiras, Portugal, 13–14 May 2025

• Larsen, Martin Vonheim & Mathiassen, Kim (2024). Achieving Sub-Pixel Platform Accuracy With Pan-Tilt-Zoom Cameras in Uncertain Times. IEEE Transactions on Robotics. ISSN 1552-3098. doi: 10.1109/TRO.2024.3508141. Full text in Research Archive Show summary

  In this paper, we present a novel method for selfcalibrating a pan-tilt-zoom (PTZ) camera system model, specifically suited for long-range multi-target tracking with maneuvering low-cost PTZ cameras. Traditionally, such camera systems cannot provide accurate mappings from pixels to directions in the platform frame due to imprecise pan/tilt measurements or lacking synchronization between the pan/tilt unit and the video stream. Using a direction-only bundle adjustment (BA) incorporating pan/tilt measurements, we calibrate camera intrinsics, rolling shutter (RS) characteristics and pan/tilt mechanics, and obtain clock synchronization between the video stream and pan/tilt telemetry. We call the resulting method PTCEE (pan/tilt camera extrinsic and intrinsic estimation). In a thorough simulation study, we show that the proposed estimation scheme identifies model parameters with sub-pixel precision across a wide range of camera setups. Leveraging the map of landmarks from the BA, we propose a method for estimating camera orientation in real-time, and demonstrate pixel-level mapping precision on realworld data. Through the proposed calibration and orientation schemes, PTCEE enables high-precision target tracking during camera maneuvers in many low-cost systems, which was previously reserved for high-end systems with specialised hardware. Code is available at github.com/ffi-no/Paper-ptz-subpix-accuracy.

• Larsen, Martin Vonheim; Rolfsjord, Sigmund Johannes Ljosvoll; Gusland, Daniel; Ahlberg, Jörgen & Mathiassen, Kim (2024). BASE: Probably a Better Approach to Visual Multi-Object Tracking. VISIGRAPP. ISSN 2184-5921. doi: 10.5220/0012386600003660. Full text in Research Archive Show summary

  The field of visual object tracking is dominated by methods that combine simple tracking algorithms and ad hoc schemes. Probabilistic tracking algorithms, which are leading in other fields, are surprisingly absent from the leaderboards. We found that accounting for distance in target kinematics, exploiting detector confidence and modelling non-uniform clutter characteristics is critical for a probabilistic tracker to work in visual tracking. Previous probabilistic methods fail to address most or all these aspects, which we believe is why they fall so far behind current state-of-the-art (SOTA) methods (there are no probabilistic trackers in the MOT17 top 100). To rekindle progress among probabilistic approaches, we propose a set of pragmatic models addressing these challenges, and demonstrate how they can be incorporated into a probabilistic framework. We present BASE (Bayesian Approximation Single-hypothesis Estimator), a simple, performant and easily extendible visual tracker, achie (More)

• Tariverdi, Abbas; Côté-Allard, Ulysse Teller Masao; Mathiassen, Kim; Elle, Ole Jakob; Kalvøy, Håvard & Martinsen, Ørjan Grøttem [Show all 7 contributors for this article] (2023). Reinforcement Learning-Based Switching Controller for a Milliscale Robot in a Constrained Environment. IEEE Transactions on Automation Science and Engineering. ISSN 1545-5955. 21(2), p. 2000–2016. doi: 10.1109/TASE.2023.3259905. Full text in Research Archive
• Sajadi, Seyed Mohammad Reza; Mathiassen, Kim; Brun, Henrik & Elle, Ole Jakob (2022). Design, Kinematic Modeling, and Validation of a Robotic-Assisted Transesophageal Echocardiography System, 2022 IEEE/SICE International Symposium on System Integration (SII 2022) : January 9-12, 2022 (Virtual Conference) Narvik, Norway. IEEE (Institute of Electrical and Electronics Engineers). ISSN 9781665445405. doi: 10.1109/SII52469.2022.9708810. Full text in Research Archive
• Tariverdi, Abbas; Mathiassen, Kim; Søyseth, Vegard; Kalvøy, Håvard; Elle, Ole Jakob & Tørresen, Jim [Show all 8 contributors for this article] (2022). Physics-Based Simulation and Control Framework for Steering a Magnetically-Actuated Guidewire. In Dilger, Lale Canan (Eds.), 2022 8th International Conference on Control, Decision and Information Technologies (CoDIT). IEEE (Institute of Electrical and Electronics Engineers). ISSN 9781665496070. doi: 10.1109/CoDIT55151.2022.9803963. Full text in Research Archive
• Sajadi, Seyed Mohammad Reza; Karbasi, Seyed Mojtaba; Brun, Henrik; Tørresen, Jim; Elle, Ole Jakob & Mathiassen, Kim (2022). Towards Autonomous Robotic Biopsy—Design, Modeling and Control of a Robot for Needle Insertion of a Commercial Full Core Biopsy Instrument. Frontiers in Robotics and AI. 9. doi: 10.3389/frobt.2022.896267. Full text in Research Archive Show summary

  This paper presents the design, control, and experimental evaluation of a novel fully automated robotic-assisted system for the positioning and insertion of a commercial full core biopsy instrument under guidance by ultrasound imaging. The robotic system consisted of a novel 4° of freedom (DOF) add-on robot for the positioning and insertion of the biopsy instrument that is attached to a UR5-based teleoperation system with 6 DOF. The robotic system incorporates the advantages of both freehand and probe-guided biopsy techniques. The proposed robotic system can be used as a slave robot in a teleoperation configuration or as an autonomous or semi-autonomous robot in the future. While the UR5 manipulator was controlled using a teleoperation scheme with force controller, a reinforcement learning based controller using the Deep Deterministic Policy Gradient (DDPG) algorithm was developed for the add-on robotic system. The dexterous workspace analysis of the add-on robotic system demonstrated that the system has a suitable workspace within the US image. Two sets of comprehensive experiments including four experiments were performed to evaluate the robotic system’s performance in terms of the biopsy instrument positioning, and the insertion of the needle inside the ultrasound plane. The experimental results showed the ability of the robotic system for in-plane needle insertion. The overall mean error of all four experiments in the tracking of the needle angle was 0.446°, and the resolution of the needle insertion was 0.002 mm.

• Tisland, Andreas; Baksaas, Magnus & Mathiassen, Kim (2022). How extending the kinematic model affects path following in off-road terrain for differential drive UGVs. Proceedings of SPIE, the International Society for Optical Engineering. ISSN 0277-786X. doi: 10.1117/12.2618731. Full text in Research Archive Show summary

  Traversal in off-road conditions for Unmanned Ground Vehicles is highly relevant for defence applications, with an increasing amount of research being put into the field. A central part of the autonomous traversal is path following, where there currently exist many stable controllers. However, conventional path following controllers often relies on ideal vehicle models that make assumptions about the terrain that are no longer valid in off-road conditions. Therefore, research is needed into how conventional controllers are affected by off-road terrain and if extending the vehicle model with relevant parameters can improve the performance. In this paper, a controller based on Active Disturbance Rejection Control and a controller based on Instantaneous Centre of Rotation are tested against a conventional controller in off-road conditions. Results from simulations illustrate how the conventional controller is affected by variations in the vehicle’s rotation centre while the proposed controllers have improved performance when simulating rough terrain conditions. Real world experiments were conducted in uneven sandy terrain, where all of the controllers showed decent performance, but the proposed controllers had the lowest cross-track error. Future Unmanned Ground Vehicle operations can improve performance by using the proposed controllers when the vehicle is experiencing rough terrain where the Instantaneous Centre of Rotation is considerably shifted from its ideal location. On the other hand, the conventional controller should produce decent performance in moderate conditions. Further research is needed to understand what types of real world conditions make the performance of the conventional controller significantly decrease, thus justifying the use of one of the proposed controllers.

• Tariverdi, Abbas; Venkiteswaran, Venkatasubramanian Kalpathy; Richter, Michiel; Elle, Ole Jakob; Tørresen, Jim & Mathiassen, Kim [Show all 8 contributors for this article] (2021). A Recurrent Neural-Network-Based Real-Time Dynamic Model for Soft Continuum Manipulators. Frontiers in Robotics and AI. doi: 10.3389/frobt.2021.631303. Full text in Research Archive Show summary

  This paper introduces and validates a real-time dynamic predictive model based on a neural network approach for soft continuum manipulators. The presented model provides a real-time prediction framework using neural-network-based strategies and continuum mechanics principles. A time-space integration scheme is employed to discretize the continuous dynamics and decouple the dynamic equations for translation and rotation for each node of a soft continuum manipulator. Then the resulting architecture is used to develop distributed prediction algorithms using recurrent neural networks. The proposed RNN-based parallel predictive scheme does not rely on computationally intensive algorithms; therefore, it is useful in real-time applications. Furthermore, simulations are shown to illustrate the approach performance on soft continuum elastica, and the approach is also validated through an experiment on a magnetically-actuated soft continuum manipulator. The results demonstrate that the presented model can outperform classical modeling approaches such as the Cosserat rod model while also shows possibilities for being used in practice.

• Mathiassen, Kim; Schneider, Frank; Bounker, Paul; Tiderko, Alexander; Cubber, Geert De & Baksaas, Magnus [Show all 12 contributors for this article] (2021). Demonstrating Interoperability Between Unmanned Ground Systems and Command and Control Systems. International Journal of Intelligent Defence Support Systems. ISSN 1755-1587. doi: 10.1504/ijidss.2021.115236. Full text in Research Archive Show summary

  This paper describes the research and experiment efforts ofthe NATO STO group IST-149-RTG capability concept demonstrator forinteroperability within unmanned ground systems and C2 and the NAAGteam of experts on UGV. The main purpose of the group was to investigatepossible standards for controlling UGVs and tests them in a real worldscenario. The efforts have been two folded, where the first effort was twoNATO groups having an experiment demonstrating interoperability betweenthe UGVs and OCUs available within the group. The Belgium contributionis done in the EU project ICARUS. Both efforts used the Joint Architecturefor Unmanned Systems (JAUS) with the interoperability profile (IOP) tosuccessfully enable interoperability between the systems. The trials showedthat it is possible to extend the systems quite easily and achieve compliancewith parts of the standard in a relatively short time.

• Mathiassen, Kim; Baksaas, Magnus; Græe, Sindre Aas; Mentzoni, Eilert André & Nielsen, Niels Hygum (2021). Making the Milrem Themis UGV ready for autonomous operations. Proceedings of SPIE, the International Society for Optical Engineering. ISSN 0277-786X. doi: 10.1117/12.2585879. Full text in Research Archive Show summary

  The usage of Unmanned Ground Vehicles (UGVs) in defence application is increasing, and much research effort is put into the field. Also, many defence vehicle producers are developing UGV platforms. However, the autonomy functionality of these systems are still in need of improvement. At the Norwegian Defence Research Establishment a project for developing an autonomous UGV was started in 2019 and use a Milrem THeMIS 4.5 from Milrem Robotics as the base platform for achieving this. In this paper we will describe the modifications made to the vehicle to make it ready for autonomous operations. We have added three cameras and a Lidar as vision sensors, for navigation we have added a GNSS, IMU and velocity radar, and all sensors get a common time stamp from a time server. All the sensors have been mounted on a common aluminium profile, which is mounted in the front of the vehicle. The vision and navigation sensors have been mounted on the common aluminium profile to ensure that the direction the vision sensors observe is known with as little uncertainty as possible. In addition to the hardware modification, a control software framework has been developed on top of Milrem’s controller. The vehicle is interfaced using ROS2, and is controlled by sending velocity commands for each belt. We have developed a hardware abstraction module that interfaces the vehicle and adds some additional safety features, a trajectory tracking module and a ROS simulation framework. The control framework has been field tested and results will be shown in the paper.

• Thoresen, Marius; Nielsen, Niels Hygum; Mathiassen, Kim & Pettersen, Kristin Y. (2021). Path Planning for UGVs Based on Traversability Hybrid A*. IEEE Robotics and Automation Letters. ISSN 2377-3766. 6(2). doi: 10.1109/LRA.2021.3056028. Full text in Research Archive Show summary

  In this letter, a new method of path planning for unmanned ground vehicles (UGVs) on terrain is developed. For UGVs moving on terrain, path traversability and collisionavoidance are important factors. If traversability is not considered, the planned path may lead a UGV into areas that will cause rough vehicle motion or lead to the UGV getting stuck if the traversability is low. The proposed path planning method is based on the Hybrid A* algorithm and uses estimated terrain traversability to find the path that optimizes both traversability and distance for the UGV. The path planning method is demonstrated using simulated traversability maps and is compared to the original Hybrid A* algorithm. The method is also verified through real-time experiments in real terrain, further demonstrating the benefits of terrain traversability optimization using the proposed path planning method. In the experiments, the proposed method was successfully applied for autonomous driving over distances of up to 270 m in rough terrain.Compared with the existing Hybrid A* method, the proposedmethod produces more traversable paths.

• Larsen, Martin Vonheim; Haavardsholm, Trym Vegard & Mathiassen, Kim (2020). In-operation calibration of clock-bias and intrinsic parameters for pan-tilt-zoom cameras based on keypoint tracking. Proceedings of SPIE, the International Society for Optical Engineering. ISSN 0277-786X. doi: 10.1117/12.2573611. Full text in Research Archive Show summary

  We propose a method for jointly estimating intrinsic calibration and internal clock synchronisation for a pantilt- zoom (PTZ) camera using only data that can be acquired in the field during normal operation. Results show that this method is a promising starting point towards using software to replace costly timing hardware in such cameras. Through experiments we provide calibration and clock synchronisation for an off-the-shelf low-cost PTZ camera, and observe a greatly improved directional accuracy, even during mild manoeuvres.

• Løvlid, Rikke Amilde; Mathiassen, Kim; Ruud, Else-Line Malene; Simonsen, Aleksander & Hermansen, Fredrik (2019). Battle Management Language for Robotic Systems Experiences from Applications on an UGV and an USV. Lecture Notes in Computer Science (LNCS). ISSN 0302-9743. 11472 LNCS, p. 302–320. doi: 10.1007/978-3-030-14984-0_23. Full text in Research Archive
• Mathiassen, Kim; Fjellin, Jørgen Enger; Glette, Kyrre Harald; Hol, Per Kristian & Elle, Ole Jakob (2016). An Ultrasound Robotic System Using the Commercial Robot UR5. Frontiers in Robotics and AI. 3. doi: 10.3389/frobt.2016.00001. Full text in Research Archive Show summary

  The use of robots in health care has increased dramatically over the last decade. One area of research has been to use robots to conduct ultrasound examinations, either controlled by a physician or autonomously. This paper examines the possibility of using the commercial robot UR5 from Universal Robots to make a tele-operated robotic ultrasound system. Physicians diagnosing patients using ultrasound probes are prone to repetitive strain injuries, as they are required to hold the probe in uncomfortable positions and exert significant static force. The main application for the system is to relieve the physician of this strain by letting the them control a robot that holds the probe. A set of requirements for the system is derived from the state-of-the-art systems found in the research literature. The system is developed through a low-level interface for the robot, effectively building a new software framework for controlling it. Compliance force control and forward flow haptic control of the robot was implemented. Experiments are conducted to quantify the performance of the two control schemes. The force control is estimated to have a bandwidth of 16.6 Hz, while the haptic control is estimated to have a bandwidth of 65.4 Hz for the position control of the slave and 13.4 Hz for the force control of the master. Overall, the system meets the derived requirements and the main conclusion is that it is feasible to use the UR5 robot for robotic ultrasound applications.

• Mathiassen, Kim; Baksaas, Magnus; Olsen, Lars Erik; Thoresen, Marius & Tveit, Bjørn (2016). Development of an Autonomous Off-Road Vehicle for Surveillance Missions, STO-MP-IST-127: Intelligence and Autonomy In Robotics. NATO Science and Technology Organization. ISSN 9789283720683. Full text in Research Archive
• Wiig, Martin Syre; Løvlid, Rikke Amilde; Mathiassen, Kim & Krogstad, Thomas Røbekk (2016). Decision Autonomy for Unmanned Vehicles, STO-MP-IST-127: Intelligence and Autonomy In Robotics. NATO Science and Technology Organization. ISSN 9789283720683. Full text in Research Archive
• Mathiassen, Kim; Glette, Kyrre & Elle, Ole Jakob (2016). Visual servoing of a medical ultrasound probe for needle insertion. IEEE International Conference on Robotics and Automation (ICRA). ISSN 1050-4729. 2016-June, p. 3426–3433. doi: 10.1109/ICRA.2016.7487520. Full text in Research Archive
• Mathiassen, Kim; Dall'Alba, Diego; Muradore, Riccardo; Fiorini, Paolo & Elle, Ole Jakob (2016). Robust real-time needle tracking in 2-D ultrasound images using statistical filtering. IEEE Transactions on Control Systems Technology. ISSN 1063-6536. PP(99), p. 1–13. doi: 10.1109/TCST.2016.2587733. Full text in Research Archive Show summary

  Percutaneous image-guided tumor ablation is a minimally invasive surgical procedure for the treatment of malignant tumors using a needle-shaped ablation probe. Automating the insertion of a needle by using a robot could increase the accuracy and decrease the execution time of the procedure. Extracting the needle tip position from the ultrasound (US) images is of paramount importance for verifying that the needle is not approaching any forbidden regions (e.g., major vessels and ribs), and could also be used as a direct feedback signal to the robot inserting the needle. A method for estimating the needle tip has previously been developed combining a modified Hough transform, image filters, and machine learning. This paper improves that method by introducing a dynamic selection of the region of interest in the US images and filtering the tracking results using either a Kalman filter or a particle filter. Experiments where a biopsy needle has been inserted into a phantom by a robot have been conducted, guided by an infrared tracking system. The proposed method has been accurately evaluated by comparing its estimations with the needle tip's positions manually detected by a physician in the US images. The results show a significant improvement in precision and more than 85% reduction of 95th percentile of the error compared with the previous automatic approaches. The method runs in real time with a frame rate of 35.4 frames/s. The increased robustness and accuracy can make our algorithm usable in autonomous surgical systems for needle insertion.

• Muradore, Riccardo; Fiorini, Paolo; Akgun, Gokhan; Barkana, Duygun Erol; Bonfe, Marcello & Boriero, Fabrizio [Show all 28 contributors for this article] (2015). Development of a cognitive robotic system for simple surgical tasks. International Journal of Advanced Robotic Systems (IJARS). ISSN 1729-8806. 12:37. doi: 10.5772/60137. Full text in Research Archive
• Mathiassen, Kim; Dall'Alba, Diego; Muradore, Riccardo; Fiorini, Paolo & Elle, Ole Jakob (2013). Real-time biopsy needle tip estimation in 2D ultrasound images, Robotics and Automation (ICRA), 2013 IEEE International Conference on. IEEE Press. ISSN 9781467356404. p. 4363–4369. doi: 10.1109/ICRA.2013.6631195. Full text in Research Archive
• Mathiassen, Kim; Hanssen, Leif & Hallingstad, Oddvar (2010). A low cost navigation unit for positioning of personnel after loss of GPS position. In Mautz, Rainer; Kunz, Melanie & Ingensand, Hilmar (Ed.), Proceedings of the 2010 International Conference on Indoor Positioning and Indoor Navigation. IEEE (Institute of Electrical and Electronics Engineers). ISSN 9781424458646. Full text in Research Archive

View all works in NVA

• Mathiassen, Kim (2023). Land Autonomy Research for the Norwegian Defence. Full text in Research Archive
• Mathiassen, Kim (2023). Land Autonomy Research for the Norwegian Defence. Full text in Research Archive
• Sajadi, Seyed Mohammad Reza; Mathiassen, Kim; Brun, Henrik & Elle, Ole Jakob (2022). Design, Kinematic Modeling, and Validation of a Robotic-Assisted Transesophageal Echocardiography System. Full text in Research Archive Show summary

  Transesophageal Echocardiography is a safe and minimally invasive tool to provide high-quality anatomic and hemodynamic information of the heart and its structures. However, the risk of exposure to a significant level of radiation during combined fluoroscopy and TEE-guided examinations and musculoskeletal disorders due to holding the probe for prolonged periods of time are two main shortcomings of using TEE manually. This paper presents the design, kinematic modeling, and validation of a novel 6 DOF robotic-assisted transesophageal echocardiography system to overcome the above mentioned shortcomings. The robotic system has been designed based on a commercially available TEE probe with 5 actuated Degrees of freedom on the TEE handle and an extra DOF to control the imaging plane. The constant curvature model is employed for the forward and inverse kinematic modeling of the robotic system. The kinematic model and the performance of the robotic system are validated with an experimental setup using a 6DOF OptiTrack real-time tracking system.

• Orhaugen, Ole Petter; Thoresen, Marius & Mathiassen, Kim (2022). The Rapidly Exploring Random Tree Funnel Algorithm. doi: 10.1109/ICMRE54455.2022.9734089. Full text in Research Archive Show summary

  This paper shows the feasibility of combining robustmotion primitives generated through the Sums Of Squaresprogramming theory with a discrete Rapidly exploring RandomTree algorithm. The generated robust motion primitives, referredto as funnels, are then employed as local motion primitives,each with its locally valid Linear Quadratic Regulator (LQR)controller, which is verified through a Lyapunov function foundthrough a Sum Of Squares (SOS) search in the function space.These funnels are then combined together at execution time bythe Rapidly-exploring-Random-Tree (RRT) planner, and is shownto provide provably robust traversal of a simulated forest environment. The experiments benchmark the RRT-Funnel algorithmagainst an RRT algorithm which employs a maximum distanceto the nearest obstacle heuristic in order to avoid collisions, asopposed to explicitly handling uncertainty. The results show thatemploying funnels as robust motion primitives outperform theheuristic planner in the experiments run on both algorithms,where the RRT-Funnel algorithm does not collide a single time,and creates shorter solution paths than the benchmark planneroverall, although it takes a significantly longer time to find asolution.

• Mathiassen, Kim; Baksaas, Magnus; Græe, Sindre Aas; Mentzoni, Eilert André & Nielsen, Niels Hygum (2021). Making the Milrem Themis UGV ready for autonomous operations. Full text in Research Archive
• Mathiassen, Kim (2021). Unmanned Ground Vehicles Research for Norwegian Defence. Full text in Research Archive
• Baksaas, Magnus; Olsen, Lars Erik & Mathiassen, Kim (2021). Evaluation of Two Path Following Controllers for an Ackermann Off-road Vehicle in Winter and Summer Conditions. doi: 10.1109/ICMRE51691.2021.9384830. Full text in Research Archive Show summary

  Off-road driving can be a challenging task with rapid changes in the driving conditions, terrain and vehicle behavior. For off-road autonomous vehicles, it is important to be robust to these changes, and parts of this robustness comes from the path following controller of the vehicle. In this paper we compare two different path following controllers using a kinematic model of Ackermann vehicles, the Stanley controller and a controller originally made for unicycles, but adapted for Ackermann vehicles. The comparison is done using an Off-road Polaris vehicle modified for autonomous driving. Two experiments are conducted, where the first experiment is during wintertime, driving with belts in snowy conditions, and the second experiments is during summer time, driving with wheels in muddy conditions. Our research vehicle can be fitted with different payloads that affect the weight and center of gravity. Therefore our main motivation for using kinematic controllers is to have a simple and robust controller that handles all situations using the same control parameters. Both controllers are used on the same path, and the cross-track errors are compared. The main conclusion is that the Stanley controller showed the most robustness against variations in driving conditions and vehicle dynamics, compared to the adapted unicycle method.

• Mathiassen, Kim (2018). Norwegian research on autonomous off-road vehicles and robotic systems. Full text in Research Archive
• Mathiassen, Kim (2017). A semi-autonomous robotic system for needle tracking and visual servoing using 2D medical ultrasound. Full text in Research Archive
• Mathiassen, Kim (2017). Kalman filtering - theory and applications in medical imaging. Full text in Research Archive
• Mathiassen, Kim; Glette, Kyrre & Elle, Ole Jakob (2016). Visual servoing of a medical ultrasound probe for needle insertion. Full text in Research Archive
• Kjølleberg, Even; Kårstad, Gry; Reuterdahl, Anne-Cathrine; Elle, Ole Jakob; Tørresen, Jim & Mathiassen, Kim (2015). Robotlegene kommer! [Internet]. NRK. Full text in Research Archive
• Novikova, Ksenia; Mathiassen, Kim & Elle, Ole Jakob (2014). Dagsrevyen 21 15.12.2014 - Utvikler kirurgirobot på UiO. [TV]. NRK. Full text in Research Archive
• Novikova, Ksenia; Mathiassen, Kim & Elle, Ole Jakob (2014). Distriktsnyheter Østlandssendingen 15.12.2014 - Utvikler kirurgirobot på UiO. [TV]. NRK. Full text in Research Archive
• Mathiassen, Kim & Elle, Ole Jakob (2014). Fjernstyrt ultralyd. Full text in Research Archive
• Mathiassen, Kim; Handini, Dilla; Nguyen, Ho Quoc Phuong & Elle, Ole Jakob (2014). Biopsy Needle Tracking using Medical Ultrasound and a Surgical Robotic System. Full text in Research Archive
• Mathiassen, Kim; Dall'Alba, Diego; Muradore, Riccardo; Fiorini, Paolo & Elle, Ole Jakob (2013). Robust Real-Time Tracking of Biopsy Needle in 2D Ultrasound Images for Automatic Insertion. Full text in Research Archive
• Mathiassen, Kim (2013). Fra Fjernstyrte Ultralydundersøkelser til delvis automatisert biopsi. Full text in Research Archive
• Nguyen, Ho Quoc Phuong; Mathiassen, Kim & Elle, Ole Jakob (2013). 3d vision based detection of skin penetration for surgical robotics. Full text in Research Archive
• Mathiassen, Kim; Dall'Alba, Diego; Muradore, Riccardo; Fiorini, Paolo & Elle, Ole Jakob (2012). Estimation of biopsy needle tip in 2D US images. Full text in Research Archive
• Mathiassen, Kim; Glette, Kyrre Harald; Høvin, Mats Erling; Hol, Per Kristian & Elle, Ole Jakob (2012). Semi-autonomous robotic systems for use in medical diagnostics and treatment. Full text in Research Archive
• Nguyen, Ho Quoc Phuong; Handini, Dilla; Mathiassen, Kim & Elle, Ole Jakob (2012). Intra-operative Reasoning & Situation Awareness Algrorithm for Kidney Tumor Cryoblation by Robot. Full text in Research Archive
• Klem, Agnes; Hoff, Jon Roar; Tørresen, Jim; Hafting, Yngve; Elle, Ole Jakob & Mathiassen, Kim [Show all 9 contributors for this article] (2012). Robotikk og moral. [Internet]. Universitas.no. Full text in Research Archive Show summary

  Reportasjen er også trykket i papirutgaven av Universitas 28.11.2012. Elektronisk versjon av papirutaven er tilgjengelig på http://static.universitas.no/docs/pdf/universitas_2012-34.pdf

• Mathiassen, Kim & Elle, Ole Jakob (2011). Autonomous Robotic Ultrasound System. Full text in Research Archive
• Mathiassen, Kim; Hanssen, Leif & Hallingstad, Oddvar (2010). A Low Cost Navigation Unit for Positioning of Personnel After Loss of GPS Position. Full text in Research Archive
• Thoresen, Marius; Baksaas, Magnus; Nielsen, Niels Hygum; Mentzoni, Eilert André; Hanevold, Morten & Kolden, David [Show all 8 contributors for this article] (2026). Development of off-road autonomy for unmanned ground vehicles. Forsvarets forskningsinstitutt . Full text in Research Archive Show summary

  Unmanned ground vehicles (UGVs) are increasingly recognized as assets that can benefit military operations, offering the potential to reduce risk to personnel. Having autonomous capabilities on board UGVs can further enhance their utility by reducing operator workload and enabling more mission capabilities. This report describes the development of a modular autonomy stack for UGVs and its evaluation through experiments in off-road terrain. The autonomy stack integrates three core capabilities – perception, motion planning, and trajectory tracking – implemented on our Milrem Themis UGV platform, Tor. This autonomy system relies on onboard sensors and local mapping to navigate without predefined paths or precise satellite positioning, aiming to address the fundamental challenge of autonomous terrain traversability. To measure performance, we defined a set of benchmark routes representing diverse terrain types, from open fields and dirt roads to narrow trails and forests. These routes serve as structured test cases for assessing autonomy requirements and identifying limitations of our system. We have conducted experiments to assess our autonomy system at FFI’s LandX demonstrations and in long-range trials. The experiments revealed that Tor with our autonomy stack can successfully navigate simple environments such as open terrain and wide vehicle trails, but struggles in complex scenarios involving dense vegetation and narrow passages. Key limitations include the lack of semantic terrain classification and robust decision making in challenging scenarios. Predictability and reliability remain major challenges, with decisions influenced by randomness rather than consistent reasoning. While our current autonomy stack is not yet ready for operational use, it provides a solid foundation for continued research and experimentation. The benchmark routes and evaluation methodology offer a repeatable framework for measuring progress, ensuring that future iterations move closer to the ultimate goal: UGVs capable of operating effectively and autonomously in demanding environments.

• Bakstad, Lorns Harald; Baksaas, Magnus; Mygland, Katrine; Eikanger, Brage Gerdssønn; Gusland, Daniel & Hauge, Mariann [Show all 23 contributors for this article] (2025). LandX21 – teknologi i framtidas stridsfelt. Forsvarets forskningsinstitutt . Full text in Research Archive Show summary

  Etter suksessen med LandX i 2020 besluttet FFI å holde LandX som et årlig eksperiment. To uker hver høst skal forskere, brukere og industri samles på Rena for å eksperimentere med teknologi og nye løsninger for Forsvaret. Eksperimentukene avsluttes med en demonstrasjon for inviterte fra hele sektoren. Målet med demonstrasjonen er å formidle forskning til relevante brukere i Forsvaret og demonstrere hvordan ny teknologi kan bidra til å endre framtidas stridsfelt i landdomenet. I 2021 var temaet for LandX situasjonsforståelse, og forskningsprosjekter fra fem forskningsprogrammer ved FFI deltok. Eksperimenteringen dekket alt fra ubemannede og autonome systemer på bakken og i lufta til sensorfusjon, målfølging og robust og sikker kommunikasjon. I tillegg markerte LandX21 åpningen av FFIs nye innovasjonsarena, ICE worx Rena. I denne rapporten oppsummerer vi innholdet og resultatene fra eksperimentene helt overordnet og peker på relevante rapporter som kan utdype teknologien ytterligere. LandX21 var en suksess. Forskningsprogrammene rapporterte i ettertid at de hadde kommet lenger og lært mer enn de hadde gjort om de ikke hadde testet i felt. Tilbakemeldingene fra tilskuerne på demonstrasjonsdagen var at forskningsarbeidet hadde høy relevans, og at det ble formidlet på en god måte. LandX skal arrangeres igjen i 2022. Da skal vi utvide omfanget, og målsetningen er å samarbeide tettere med brukere for å få enda bedre kobling mellom forskningen og operativ bruk.

• Mentzoni, Eilert André; Baksaas, Magnus; Bakstad, Lorns Harald; Bjordal, Halvor; Bjerke, Sven & Mygland, Katrine [Show all 26 contributors for this article] (2024). LandX22 – Experimentation with uncrewed systems in a future combat unit. Forsvarets forskningsinstitutt . ISSN 9788246435404. Full text in Research Archive Show summary

  LandX22 was a collaborative experiment and collaboration between Norwegian Defence Research Establishment (FFI), Combat Lab, Kongsberg Defence & Aerospace (KDA) and Teleplan. From FFI, four projects participated. The goals of the experiment was to test and demonstrate how uncrewed systems, both autonomous and remote controlled, can be used in a conceptual Future Combat Unit (FCU) to combat an attacking mechanized enemy force. The experiment and demonstration took place between September 26th to September 30th, the integration week, and between October 17th and October 20th, where the last day was the visitor’s day and demonstration. The experiment included many different systems developed at FFI. Two Unmanned Ground Vehicle (UGV) systems, one for testing autonomy and the other for testing manned-unmanned teaming, and two Unmanned Areal Vehicle (UAV) systems; swarm and interceptor UAVs. Swarm UAVs demonstrated increased situational awareness needing only a single operator controlling four UAVs, and the Interceptor UAV successfully took down a target UAV. The Manned unmanned teaming (MUM-T) experiment was also successful, enabling a single operator to operate the UGV and Remote Weapon Station (RWS) from a single Operator Control Unit (OCU) to combat enemy forces. The experiment also showed that improving the operators situational awareness is needed, as the experimental camera setup used had some shortcomings. The UGV autonomy experiment was partly successful, as the UGV Tor had autonomy-sensor hardware issues, and had at times troubles with the autonomous driving. The scouting activity using an elevated surveillance sensor on the other hand was a success, enabling other forces to combat the identified enemy forces. Combat Lab’s primary purpose during LandX, providing FFI with a live video feed from an elevated tethered drone directly integrated in to the mission network, was successfully delivered. The secondary purpose, endurance experiments with tethered drones, gave insights in to the capabilities of the tested system and was successfully conducted. Teleplan distributed video, own position and field of view from the different systems used during the demonstration on the mission network. Teleplan also demonstrated the capabilities of Teleplan Tactical Media Suite for the video feeds, and demonstrated that new systems/technologies can be integrated and collaborate with existing systems, such as CV9030N and drones.

• Schneider, Frank; Mathiassen, Kim; Bounker, Paul; Glowka, Jakub; Tiderko, Alexander & Baksaas, Magnus [Show all 9 contributors for this article] (2021). Capability Concept Demonstrator for Interoperability within Unmanned Ground Systems and C2. NATO Science and Technology Organization. doi: 10.14339/STO-TR-IST-149. Full text in Research Archive Show summary

  This report describes the research and experiment efforts of the NATO STO group IST-149-RTG Capability Concept Demonstrator for Interoperability within Unmanned Ground Systems and C2. Unmanned Ground Vehicles (UGVs) are becoming increasingly relevant in the modern battle-space. The main purpose of the group was to investigate possible standards for controlling UGVs from Operator Control Units (OCUs) and receiving data back, and tests them in a real world scenario. The efforts in the project have been two folded. The Belgium contribution is work done in the EU project ICARUS. The second effort was a combined effort in the group to have an experiment demonstrating interoperability between the UGVs and OCUs available within the group. Both efforts used the Joint Architecture for Unmanned Systems (JAUS) with the Interoperability Profile (IOP) to successfully enable interoperability between the systems. The trials showed that it is possible to extend the systems quite easily and achieve compliance with parts of the standard in a relatively short time. Both Fraunhofer FKIE and TARDEC had developed software to pass information from the IOP domain to the Robotic Operating System (ROS). As this was a successful trial, the next step would be to test interoperability using higher level functions.

• Danielsen, Tone & Mathiassen, Kim (2019). Base defence demonstration at Trident Juncture 2018 – TACT unmanned systems for base and force protection. Forsvarets forskningsinstitutt . ISSN 9788246431758. Full text in Research Archive Show summary

  Trident Juncture 2018 (TRJE18) var en høyprofilert militærøvelse i Norge høsten 2018. Sammen med NATO Allied Command Transformation (ACT) arrangerte Forsvarets forskningsinstitutt (FFI) en stor arena for demonstrasjoner ved Værnes. Denne rapporten beskriver baseforsvarsdemonstrasjonen, som var en del av dette. I denne øvelsen var demonstrasjonen en Transformational Activity (TACT) under NATO ACT. Demonstrasjonen viste et baseforsvarskonsept hvor vi brukte ubemannede systemer, der sensorer og effektorer var koblet sammen i et nettverk for å gi økt situasjonsforståelse og redusere tiden fra en trussel blir oppdaget til man reagerer på eller angriper trusselen. Hensikten med denne aktiviteten i TRJE18 var todelt. Det primære målet var å demonstrere for viktige beslutningstakere hvilket potensial ubemannede systemer har for beskyttelse av baser og personell. Det andre målet var å få soldater til å bruke systemet slik at de kan få innsikt i systemets fordeler og hva som kan forbedres. FFI gjennomførte også demonstrasjon av baseforsvarskonsept i 2016 og i 2017, og TRJE18-demonstrasjonen var en fortsettelse av dette. 2018-demonstrasjonen ble gjort i samarbeid med mange industripartnere. Demonstrasjonen ble holdt på Sutterøya nordvest for Værnes flyplass. Scenarioet var at soldater fra Heimevernet skulle beskytte halvøya mot angrep fra nordvest. Til hjelp hadde de to våpenstasjoner (RWS), ett ubemannet bakkekjøretøy (UGV), én ubemannet overflatefarkost (USV), én nano ubemannet luftfarkost (UAV), forskjellige bakkesensorer i området, ett stridsledelsessystem (BMS) og ett soldatsystem for kommando og kontroll. Demonstrasjonen hadde mange besøkende, deriblant Det nordatlantiske råd og NATOs militærkomité. De forskjellige tekniske undersystemene måtte integreres med hverandre. Dette ble gjort ved å bruke Integrated Combat Solution (ICS)-teknologien til Kongsberg Defence & Aerospace. For å få til dette var det nødvendig å etablere et nettverk mellom de forskjellige undersystemene, noe som involverte mange radiosystemer. I tillegg måtte alle undersystemene integreres med ICS. Vårt baseforsvarskonsept ble demonstrert for mange viktige beslutningstakere, og vi lyktes således med vår hovedmålsetting. Det andre målet, som var å evaluere den operative nytten til systemet, lyktes vi ikke like bra med. Dette målet ble bare delvis oppnådd, noe som skyldtes tidsbegrensninger.

• Elle, Ole Jakob; Glette, Kyrre; Høvin, Mats Erling; Hol, Per Kristian & Mathiassen, Kim (2017). A semi-autonomous robotic system for needle tracking and visual servoing using 2D medical ultrasound. Universitetet i Oslo. Full text in Research Archive Show summary

  The main aim of the thesis is to contribute to a semi-autonomous active sensing system for needle tracking during percutaneous needle insertion. The objective is twofold: first to develop a system for acquiring ultrasound images, then to analyze these images in order to track the needle. The thesis is thus divided into two main lines of research: (1) investigate whether it is feasible to make a robotic system for acquiring ultrasound images using commercially available components; (2) investigate how to track a needle using 2D ultrasound images and possibly other sensor information in real-time. In this thesis we have developed an ultrasound robotic system using the UR5 robot from Universal Robots, based on a set of requirements derived from the state of the art in the literature. The system has both force and haptic control. We developed and tested several novel methods for tracking a needle in an ultrasound image. In addition, a novel visual servoing method has been developed to ensure that the needle lies in the imaging plane of the ultrasound probe during insertions. The thesis concludes that it is feasible to make an ultrasound robotic system using commercially available components and shows that such a system meets the derived requirements. It also concludes that the novel needle tracking methods presented are both accurate and precise compared to previous methods presented in the literature. It is also shown that using velocity measurements from a needle insertion robot significantly improves the both the accuracy and precision, compared to only using ultrasound images. The visual servoing method shows promise for solving the alignment problem of keeping the needle in the imaging plane of the ultrasound probe.

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