Blar i SINTEF Open på forfatter "Gravdahl, Jan Tommy"
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A Machine Vision System for Robust Sorting of Herring Fractions
Guttormsen, Erik; Toldnes, Bendik; Bondø, Morten Steen; Eilertsen, Aleksander; Gravdahl, Jan Tommy; Mathiassen, John Reidar Bartle (Journal article; Peer reviewed, 2016-07-16)Among the rest raw material in herring (Clupea harengus) fractions, produced during the filleting process of herring, there are high-value products such as roe and milt. As of today, there has been little or no major effort ... -
Body Shape and Orientation Control for Locomotion of Biologically-Inspired Snake Robots
Rezapour, Ehsan; Pettersen, Kristin Ytterstad; Gravdahl, Jan Tommy; Liljebäck, Pål (Chapter, 2014)This paper considers guidance-based motion control of planar snake robots using a dynamic feedback control law. We first present the Euler-Lagrange equations of motion of the robot. Subsequently, we introduce a dynamic ... -
Compressor Surge Control Using Lyapunov Neural Networks
Neverlien, Åse; Moe, Signe; Gravdahl, Jan Tommy (Peer reviewed; Journal article, 2020)In this paper surge control in a compression system using a close-coupled valve (CCV) is proposed. The control design is based on Lyapunov control theory in combination with neural networks (NNs) and focuses on minimization ... -
Learning-based Robust Model Predictive Control for Sector-bounded Lur'e Systems
Seel, Katrine; Haring, Mark A. M.; Grøtli, Esten Ingar; Pettersen, Kristin Ytterstad; Gravdahl, Jan Tommy (Peer reviewed; Journal article, 2021)For dynamical systems with uncertainty, robust controllers can be designed by assuming that the uncertainty is bounded. The less we know about the uncertainty in the system, the more conservative the bound must be, which ... -
Linear Antisymmetric Recurrent Neural Networks
Moe, Signe; Remonato, Filippo; Grøtli, Esten Ingar; Gravdahl, Jan Tommy (Peer reviewed; Journal article, 2020)Recurrent Neural Networks (RNNs) have a form of memory where the output from a node at one timestep is fed back as input the next timestep in addition to data from the previous layer. This makes them highly suitable for ... -
Mid-Level MPC and 6 DOF Output Path Following for Robotic Manipulators
Arbo, Mathias Hauan; Grøtli, Esten Ingar; Gravdahl, Jan Tommy (Journal article; Peer reviewed, 2017)In this article we discuss some of the benefits of using an MPC as a mid-level controller between the path generator and the low-level joint controller of a robot system. The MPC handles rudimentary runtime constraints ... -
Neural Network-based Model Predictive Control with Input-to-State Stability
Seel, Katrine; Grøtli, Esten Ingar; Moe, Signe; Gravdahl, Jan Tommy; Pettersen, Kristin Ytterstad (Peer reviewed; Journal article, 2021)Learning-based controllers, and especially learning-based model predictive controllers, have been used for a number of different applications with great success. In spite of good performance, a lot of these cases lack ... -
A novel hybrid analysis and modeling approach applied to aluminum electrolysis process
Lundby, Erlend Torje Berg; Rasheed, Adil; Gravdahl, Jan Tommy; Halvorsen, Ivar Johan (Peer reviewed; Journal article, 2021)Aluminum electrolysis cells are characterized by harsh environments where several measurements have to be done manually. Due to the operational costs related to manual sampling, the sampling rates of these measurements are ... -
On Model Predictive Path Following and Trajectory Tracking for Industrial Robots
Arbo, Mathias Hauan; Grøtli, Esten Ingar; Gravdahl, Jan Tommy (Journal article; Peer reviewed, 2017)In this article the model predictive path following controller and the model predictive trajectory tracking con-troller are compared for a robotic manipulator. We consider both the Runge-Kutta and collocation based ... -
On the globally exponentially convergent immersion and invariance speed observer for mechanical systems
Arbo, Mathias Hauan; Grøtli, Esten Ingar; Gravdahl, Jan Tommy (Journal article; Peer reviewed, 2017)In this article we present a reformulation of the invariance and immersion speed observer of Astolfi et al. as applied to mechanical systems with bounded inertia matrices. This is done to explore the possibility of its ... -
Path Following Control of Underactuated Surface Vessels in the Presence of Multiple Disturbances
Caharija, Walter; Sørensen, Asgeir Johan; Pettersen, Kristin Ytterstad; Greco, Marilena; Gravdahl, Jan Tommy (Chapter, 2019-06-25)An integral version of the line-of-sight guidance method is shown to compensate for both kinematic and dynamic disturbances generated by wind, waves and sea currents. The guidance law is designed for path following tasks ... -
Path Following, Obstacle Detection and Obstacle Avoidance for Thrusted Underwater Snake Robots
Kelasidi, Eleni; Moe, Signe; Pettersen, Kristin Ytterstad; Kohl, Anna M; Liljebäck, Pål; Gravdahl, Jan Tommy (Journal article; Peer reviewed, 2019)The use of unmanned underwater vehicles is steadily increasing for a variety of applications such as mapping, monitoring, inspection and intervention within several research fields and industries, e.g., oceanography, marine ... -
Real-time temporal adaptation of dynamic movement primitives for moving targets
Østvik, Andreas; Grøtli, Esten Ingar; Vagia, Marialena; Gravdahl, Jan Tommy (Chapter; Peer reviewed, 2021)This work is aimed at extending the standard dynamic movement primitives (DMP) framework to adapt to real-time changes in the task execution time while preserving its style characteristics. We propose an alternative ... -
Set-based collision avoidance applications to robotic systems
Moe, Signe; Pettersen, Kristin Ytterstad; Gravdahl, Jan Tommy (Peer reviewed; Journal article, 2020)A robotic system can consist of a single or multiple agents with a fixed or mobile base, with full or under-actuation, and possibly redundancy. Collision avoidance is a crucial task for any robotic system and is necessary ... -
Snake Robots - From Biology to Nonlinear Control
Pettersen, Kristin Ytterstad; Liljebäck, Pål; Stavdahl, Øyvind; Gravdahl, Jan Tommy (Journal article, 2013)Inspired by the motion of biological snakes, this paper presents an overview of recent results in modelling and control of snake robots. The objective of the research underlying this paper is to contribute to the mathematical ... -
Stability analysis of snake robot locomotion based on averaging theory
Liljeback, Pål; Pettersen, Kristin Ytterstad; Stavdahl, Øyvind; Gravdahl, Jan Tommy (Journal article; Peer reviewed, 2011)This paper investigates the controllability and stability properties of a planar snake robot influenced by anisotropic viscous ground friction. An analysis of the model shows that any asymptotically stabilizing control law ... -
Stable and robust neural network controllers
Sterud, Camilla; Moe, Signe; Gravdahl, Jan Tommy (Chapter, 2021)Neural networks are expressive function approimators that can be employed for state estimation in control problems. However, control systems with machine learning in the loop often lack stability proofs and performance ... -
Viscoelastic Properties of Cells: Modeling and Identification by Atomic Force Microscopy
Ragazzon, Michael Remo Palmén; Gravdahl, Jan Tommy; Vagia, Marialena (Journal article; Peer reviewed, 2017)Identification of mechanical properties of cells has previously been shown to have a great potential and effectiveness on medical diagnosis. As a result, it has gathered increasing interest of researchers over the recent ... -
Wire-arc additive manufacturing of structures with overhang: Experimental results depositing material onto fixed substrate
Evjemo, Linn Danielsen; Langelandsvik, Geir; Moe, Signe; Danielsen, Morten Høgseth; Gravdahl, Jan Tommy (Peer reviewed; Journal article, 2022)As additive manufacturing (AM) technology grows both more advanced and more available, the challenges and limitations are also made more evident. Most existing solutions for AM build structures layer by layer using strictly ...