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Vision-aided Speed Modulation System to Enhance Seaworthiness of Autonomous Planing Crafts

The present study focuses on enhancing the operationability and seaworthiness of Autonomous Planing Crafts’ (APC) in seaway by employing an autonomous speed setting mechanism as a response to the APC behavior when operating in real seaways. The mechanism, embedded in the craft’s autonomous navigation system, employs a motion computation model termed Motion Assessment of Planing Craft (MAPC) where the sea state input data is provided by a dedicated vision system.In this study, the principles of an autonomous speed setting mechanism for APCs is presented. To enhance the operationability of planing crafts, the capability to predict the accelerations and motions these crafts are expected to exhibit based on the knowledge of the incoming waves is necessary. As a response to this demand, a MAPC model was developed, The MAPC model is based on the 2-dimensional strip theory, improves previously developed motion assessment models by implementing a near transom pressure correction and modified added mass coefficients and provides accurate results for the accelerations, angular velocities and expected motions in the longitudinal plane and in the time domain. To validate and calibrate the MAPC a Jet-Ski was retrofitted to an APC platform and instrumented with an Inertial Measurement System (IMS) to measure and record the linear accelerations and angular velocities experienced by the craft in seaway. The incoming waves were measured by a separately deployed wave buoy. The wave-induced pitch and vertical acceleration as computed by the model has been compared with these experimental data and the differences are addressed.