Kristin Ytterstad Pettersen

Learn More
In this paper, we address the tracking problem for an underactuated ship using two controls, namely surge force and yaw moment. A simple state-feedback control law is developed and proved to render the tracking error dynamics globally -exponentially stable. Experimental results are presented where the controller is implemented on a scale model of an(More)
Explicit formulas of smooth time-varying state feedbacks, which make the origin of an underactuated surface vessel globally uniformly asymptotically stable, are proposed. The construction of the feedback extensively relies on the backstepping approach. The feedbacks constructed are time-periodic functions.
The paper considers feedback stabilization of the position and attitude of an autonomous underwater vehicle (AUV) with a reduced number of actuators. A nonlinear model describing both the dynamics and the kinematics of an AUV is studied. The paper shows that previous results on attitude stabilization of a spacecraft can be applied to exponentially stabilize(More)
In this paper we propose a Leader/Follower output feedback synchronization scheme for control of the attitude of two satellites when angular velocity measurements are not available. Nonlinear observers are used to estimate the angular velocities. The attitudes of the satellites are represented by unit quaternions, and the control design is based on(More)
Increasing efficiency by improving the locomotion methods is a key issue for underwater robots. Hence, an accurate dynamic model is important for both controller design and efficient locomotion methods. This paper presents a model of the kinematics and dynamics of a planar, underwater snake robot aimed at control design. Fluid contact forces and torques are(More)