• 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 ...
    • 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 ...
    • 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 ...
    • 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 ...
    • 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 ...