The design method research of the control system for Autonomous Underwater Vehicle (AUV) using Linear Matrix Inequality (LMI)
Youhei Nasuno, Etsuro Shimizu, Taro Aoki, Ikuo Yomamoto, Tadahiro Hyakudome, Satoshi Tsukioka, Hiroshi Yoshida, Shojiro Ishibashi, Masanori Ito, Ryoko Sasamoto · 제어로봇시스템학회 국제학술대회 논문집 · 2005
Fig.1 Autonomous Underwater Vehicle ‘MR-X1’ Although 70 percents on the surface of the Earth is the ocean, a lot of unexplored parts have been left. In these days, efficient investigations of the ocean and the seabed have been interested. However, undersea is the extreme environment that we can’t step into easily. Therefore operating robots for taking over from human being is desired. If such kind of robots had been developed, we can avoid danger. In order to realize it, an Independent Administrative Corporation Japan Agency for Marine-Earth Science and Technology (JAMSTEC) is developing light-and-small Autonomous Underwater Vehicles (AUV) to explore the ocean. The AUV named ‘MR-X1’ (Marine Robot Experimental 1) can cruise, investigate and observe by itself without human’s help. In order to be able to turn in a small space and explore efficiently, ‘MR-X1’ has five thrusters. One main thruster is for the forward and the backward motion, two thrusters are for the horizontal motion and two thrusters are for the vertical motion. In this paper, the motion control problem of this AUV ‘MR-X1’ is considered. In order to operate ‘MR-X1’, five thrusters have to be controlled appropriately. Since two vertical thrusters set up by inclining from the perpendicular, if these vertical thrusters are rotated, ‘MR-X1’ not only moves the vertical direction but also moves the horizontal direction. In the case of considering the cruising ‘MR-X1’ with the constant altitude, both vertical and horizontal thrusters have to be controlled appropriately. The present paper considers that ‘MR-X1’ is controlled to make it go straight on surge direction, and stop at the targeting point with the constant altitude. Since the dynamic property of ‘MR-X1’ is changed by the influence of the speed, the mathematical model of ‘MR-X1’ becomes the nonlinear model. In order to design a controller for ‘MR-X1’, we generally apply nonlinear control theories or linear control theories with some constant speed situation. If the controller is designed by applying the Linear Quadratic (LQ) optimal control theory, the obtained controller only compensates the optimality at the designed speed situation, and does not compensate the stability at another speed situations. In order to solve this problem, this paper proposes a controller design method using Linear Matrix Inequalities (LMIs), which can adapt the speed variation of ‘MR-X1’. By applying this method, we will be able to find suitable gain on the speed variation of ‘MR-X1’. And examples of numerical analysis using our designed controller are shown. The design method research of the control system for Autonomous Underwater Vehicle (AUV) using Linear Matrix Inequality (LMI) Youhei Nasuno, Etsuro Shimizu, Taro Aoki, Ikuo Yomamoto, Tadahiro Hyakudome, Satoshi Tsukioka, Hiroshi Yoshida, Shojiro Ishibashi, Masanori Ito, Ryoko Sasamoto,