Session: 05-05-02 Aquaculture and Related Technology II

Paper Number: 108083

108083 - Lstm Based Model Predictive Control of Motion Stabilized Platform to Equip Doppler Lidar for Offshore Wind Observations 

It is necessary to obtain actual wind state at the sea area where offshore wind farm will be constructed to realize its profitability and safety.  Our research group has been investigating methods to reduce motion of floating platform caused by wave, wind and current for offshore wind observations by Doppler Lidar, and has proposed a spar-buoy with ring-fin motion stabilizer.  However, the spar-buoy is not small, therefore it requires high installation cost. 

As another method, in this study, a controlled rigid body swing as a motion stabilized platform to place on floating structure is investigated numerically.  First, for a single pendulum type motion stabilized platform on a spar-buoy type floating plat form with a tension-moored, the sequential control torque required to cancel external torque is calculated.  Next, one step ahead motion velocity and acceleration of spar-buoy type floating platform are predicted by using LSTM (Long Short Term Memory) model, which is a kind of machine learning model for time series forecasting  Based on predicted results, the effectiveness of model predictive control to reduce its motion is tried to confirm.  However, it is difficult to reduce stabilized platform motion because of prediction error.  Then, skyhook dumper is used to damp undesired control torque caused by prediction error.  As a result, magnification factor of motion amplitude of the single pendulum type motion stabilized platform becomes less than one.  Moreover, this control method is applied to a counter-weight type motion stabilized platform, which is an improved single pendulum type, and the effectiveness is verified. 

Presenting Author: Mizuki Kinugasa Osaka Metropolitan University

Presenting Author Biography: My name is Mizuki Kinugasa and a graduate student at Osaka Metropolitan University.

Authors:

Mizuki Kinugasa Osaka Metropolitan University
Yusuke Yamamoto Osaka Metropolitan University
Daisuke Terada National Defense Academy of Japan
Toru Katayama Osaka Metropolitan University