A WINCH REFERENCE CONTROL SYSTEM FOR SEMI-PELAGIC TRIPLE TRAWLING - WITH FULL-SCALE SEA TRIALS

摘要

Multi-rig bottom trawling can negatively impact the seabed, and the bottom contact forces contribute to the total towing resistance. Lifting the doors from the seabed can reduce some of the trawl gear's influence on the seabed and save fuel costs. In this study we evaluated a simple reference controller designed to control a trawl door's distance from the seabed. This was achieved by providing desired warp lengths to a controller, which then regulated the distance via a low-pressure hydraulic winch. The reference controller algorithm uses an anti-windup proportional-integral controller with saturation of winch acceleration and speed. Herein, we present results of a full-scale sea trial conducted using a triple shrimp trawl with trawl doors towed close to the seabed. Our results demonstrate the feasibility of controlling the trawl doors' altitude above the seabed using only winch-actuated feedback.