A basic research on the improvement of propulsion maneuvering system and the automatic motion control of SHINKAI6500

Abstract

SHINKAI6500, a manned-submersible possessed by JAMSTEC (Japan Marine Science and Technology Center) has made great results for 10 years since it started operation. Recently the sophisticated ship maneuvering technology has been required such as hovering under irregular current or moving along obstacles like a wall. The response of thrusters equipped with SHINKAI6500 in present is not so fast because they were mainly designed to move the vehicle straightly and to reduce the radiation noise. Moreover they are manipulated individually, so it is difficult to do operations as mentioned and depends on operator's skills. Then this study was carried out as a basic research to develop the propulsion maneuvering system that enables quick motion and advanced position attitude control using multiple rapid response thrusters and to reduce the burden of operators by using automatic control with those thrusters. First in this study, to improve the response of thrusters, experimental thrusters were developed and real sea test at which they were equipped with SHINKAI6500 temporarily was executed. It was ensured that the thrust and response of the thrusters are adequate and they can sufficiently improve the motion response of the vehicle. Secondly in order to get more precise positioning compared with conventional acoustic positioning system, the test to use Doppler sonar as a positioning sensor by measuring the relative velocity to the bottom was executed. It was verified that it is possible to get enough accuracy. At last, the test of station-keeping control on the forward-backward direction was tried as a basic test that the vehicle motion was controlled by automatic control. In this test, "optimum control" of modern control algorithm was adopted as an algorithm generally used, and in addition, the "Ossman's adaptive control" algorithm was used to better position control accuracy. The results shows that it is possible to keep position at the high accuracy that 2/spl sigma/ is 4-5 mm.