Unmanned Water Craft Identification and Adaptive Control in Low-Speed and Reversing Regions

Abstract

This paper treats L 1 adaptive hovering control of an unmanned surface vehicle in a station-keeping mode where a region of zero control authority and under-actuation are main challenges. Low-speed and reversing dynamics are identified from full scale sea trials, and parameter uncertainty is estimated. With significant parameter variation, an L 1 adaptive controller is employed for heading control. The L 1 family of controllers allows for several topologies and an architecture is suggested that suits heading control of a vessel, the requirements of which differ from that of previous L 1 literature. The control design is tackled directly in discrete time to allow a fast embedded implementation in the vehicle. Analysis of robustness, tracking performance and wave disturbance response are detailed in the paper.

Smart Sensor Based Obstacle Detection for High-Speed Unmanned Surface Vehicle

“…1 using the NASREM model (Albus et al, 1989), where the first steps for plant modelling and L 1 adaptive controllers for way-point navigation and station keeping were conducted by Svendsen et al (2012) and Theisen et al (2013), respectively. Figure 4 shows a camera image that displays an indication of the radar vertical FOV (yellow), the position of the detected obstacle (x O , y O ) (blue) and the estimated horizon line given by (y H,0 , φ H ) (red).…”

Comparing Nonlinear Adaptive Motion Controllers for Marine Surface Vessels

“…In (Svendsen et al, 2012), an adaptive robust control system was developed to govern the steering of a high-speed unmanned watercraft maintaining uniform performance across the operational envelope. Based on these results, the authors in (Theisen et al, 2013) developed an L 1 adaptive hovering control of an unmanned watercraft in a station-keeping mode. In addition, (Ren et al, 2014) used L 1 adaptive control to improve the steering of a surface vessel along a predefined path.…”