• Anti-Slug Control Experiments Using Nonlinear Observers 

      Jahanshahi, Esmaeil; Skogestad, Sigurd; Grøtli, Esten Ingar (Journal article; Peer reviewed, 2013)
      Abstract: To prevent slug-flow on offshore oil production units, controlling a subsea pressure is the recommended solution. However, the subsea pressure is not often available as a measurement. The top-side pressure is ...
    • Bin Picking of Reflective Steel Parts using a Dual-Resolution Convolutional Neural Network Trained in a Simulated Environment 

      Dyrstad, Jonatan Sjølund; Bakken, Marianne; Grøtli, Esten Ingar; Schulerud, Helene; Mathiassen, John Reidar Bartle (Journal article; Peer reviewed, 2018)
      We consider the case of robotic bin picking of reflective steel parts, using a structured light 3D camera as a depth imaging device. In this paper, we present a new method for bin picking, based on a dual-resolution ...
    • Bin Picking of Reflective Steel Parts Using a Dual-Resolution Convolutional Neural Network Trained in a Simulated Environment 

      Dyrstad, Jonatan Sjølund; Bakken, Marianne; Grøtli, Esten Ingar; Schulerud, Helene; Mathiassen, John Reidar Bartle (Peer reviewed, 2019)
      We consider the case of robotic bin picking of reflective steel parts, using a structured light 3D camera as a depth imaging device. In this paper, we present a new method for bin picking, based on a dual-resolution ...
    • Bruk av droner i nordområdene 

      Bakken, Trond; Johnsen, Stig Ole; Holmstrøm, Sture; Merz, Mariann; Transeth, Aksel Andreas; Grøtli, Esten Ingar; Risholm, Petter; Storvold, Rune (Research report, 2019)
      Formålet med denne rapporten er å vise eksempler på bruk av fjernstyrte og autonome droner i petroleumssektoren og vise hvilke utviklingstrender innen droneteknologi som er viktige. Utfordringer og muligheter for bruk av ...
    • 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 ...
    • Motion- and Communication-Planning of Unmanned Aerial Vehicles in Delay Tolerant Network using Mixed-Integer Linear Programming 

      Grøtli, Esten Ingar; Johansen, Tor Arne (Journal article; Peer reviewed, 2016)
      Large amounts of data are typically generated in applications such as surveillance of power lines and railways, inspection of gas pipes, and security surveillance. In the latter application it is a necessity that the data ...
    • Nonlinear model-based control of two-phase flow in risers by feedback linearization 

      Jahanshahi, Esmaeil; Skogestad, Sigurd; Grøtli, Esten Ingar (Journal article, 2013)
      Active control of the production choke valve is the recommended solution to prevent severe slugging flow conditions at offshore oilfields. The slugging flow constitutes an unstable and highly nonlinear system; the gain of ...
    • Nonlinear observer design for a Greitzer compressor model 

      Backi, Christoph Josef; Gravdahl, Jan Tommy; Grøtli, Esten Ingar (Chapter; Conference object; Peer reviewed, 2013)
      In this paper two different observers for a nonlinear compressor model have been developed and compared: A nonlinear observer based on a circle criterion design and an Extended Kalman Filter. Both of these observers ...
    • On Model Predictive Path Following and Trajectory Tracking for Industrial Robots 

      Arbo, Mathias Hauan; Grøtli, Esten Ingar; Gravdahl, Jan Tommy (Conference object; 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 ...
    • Optimal trajectory planning for robotized tiling of floors 

      Nornes, Stein Melvær (Master thesis, 2013)
      This thesis describes the strategy of a new approach for automated tilesetting currently under development by nLink AS in Sogndal. The main focus of the thesis is the development of an appropriate strategy for path planning ...
    • Perception for obstacle-aided locomotion of snake robots 

      Lerø, Fredrik Leine (Master thesis, 2017)
      The goal of this project was to provide an obstacle-aided snake robot with improved perceptual capability. This implies ensuring that objects located in the snakes' close proximity get a high resolution digital representation. ...
    • Robotic Bin-Picking under Geometric End-Effector Constraints: Bin Placement and Grasp Selection 

      Gravdahl, Irja; Seel, Katrine; Grøtli, Esten Ingar (Chapter, 2019)
      In this paper we demonstrate how path reachability can be taken into account when selecting among predetermined grasps in a bin-picking application, where grasps are supplied independently of the robot at hand. We do this ...
    • Robust stability and control of spacecraft formations 

      Grøtli, Esten Ingar (Doktoravhandlinger ved NTNU, 1503-8181; 2010:1, Doctoral thesis, 2010)
      The work of this thesis is focused on the robustness of control laws for space-craft formation. Robustness in this case refers to the ability of the system to withstand persistent perturbations, and to keep some of the ...
    • Robustness of ISS systems to inputs with limited moving average: Application to spacecraft formations 

      Grøtli, Esten Ingar; Panteley, Elena; Chaillet, Antoine; Gravdahl, Jan Tommy (Journal article; Peer reviewed, 2016)
      We provide a theoretical framework that fits realistic challenges related to spacecraft formation with disturbances. We show that the input-to-state stability of such systems guarantees some robustness with respect to a ...
    • Semiglobal exponential stability of a counter-current and co-current guidance scheme 

      Caharija, Walter; Grøtli, Esten Ingar; Pettersen, Kristin Ytterstad (Journal article; Peer reviewed, 2018)
      A control technique for counter-current and co-current guidance of underactuated marine vehicles is revisited and stronger stability properties are shown. In particular, the stronger property of uniform semiglobal exponential ...
    • Use of Augmented Reality in Aquaculture 

      Stene, Anders (Master thesis, 2019)
      I utvidet virkelighet(eng: Augmented reality) brukes datamaskin-genererte objekter og visualiseringer til å forbedre oppfatningen av virkeligheten, gjennom å legge til mer klarhet og data. I løpet av de siste årene har ...
    • Vive for Robotics 

      Astad, Morten Andre (Master thesis, 2019)
      Bruken av en HTC Vive; et system for virtuell virkelighet og dets innovative sporingsteknologi er utforsket for å opprette en tilnærmet en-til-en avbildning til den virtuelle representasjonen av en robot celle. Denne ...
    • Vive for Robotics: Rapid Robot Cell Calibration 

      Astad, Morten Andre; Arbo, Mathias Hauan; Grøtli, Esten Ingar; Gravdahl, Jan Tommy (Chapter, 2019)
      The use of an HTC Vive; a virtual reality (VR) system and its innovative tracking technology is explored in order to create an approximate one-to-one mapping to the virtual representation of a robot cell. The mapping is ...