Yutaka Nagashima

Development of a Compact Hybrid Underwater Vehicle Using Variable Vector Propeller

This paper describes an autonomous underwater vehicle (AUV) with fuzzy controller and PID controller. Our AUV is compact and light in weight by employing variable vector (VARIVEC) propeller and compact controller. The AUV is autonomously controlled by utilizing the electronic compass, collision avoidance sonar, depth sensor and GPS receiver unit. A fuzzy controller and PID controller have designed and examined in autonomous navigation. Experimental results indicate that our AUV can move along the targeted path and hold the desired position and the depth. Furthermore, we have responded to demand of fisheries and environmental survey companies, the untethered remotely operated vehicle (UROV) is developed for monitoring the real-time image under the sea. The feature of the UROV is controlled utilizing both of wireless and optical fiber. The UROV is controlled smoothly and clearly image is captured by remote control method. We can survey the buried cultural property in the field of maritime archaeology.

Compact underwater vehicle with acoustic link for communication and positioning

This paper describes the development of autonomous underwater vehicle using variable vector propellers with the distributed controller and underwater acoustic communication system. Also presented is a novel technique of controlling the servomotors using the field programmable gate array (FPGA). Moreover, this paper also describes the 3D positioning technique for underwater vehicle. The digital signal processing by FPGA technology has enabled us to build compact, fast and highly reliable systems.

Development of a compact untethered remotely operated vehicle

Recently, the scientific investigations of marine environment, marine products and algae fields often require the use of underwater vehicle to perform survey and monitoring tasks. This paper describes a compact unthethered remotely operated vehicle (UROV). The vehicle is compact and light in weight by employing a VARIVEC propeller. The UROV operator controls by the UROV monitor including the data of GPS, electronic compass, sonar, depth and range sensor. The sensor data are extracted smartly by the Programmable System on Chip (PSoC) microprocessor. The performance of UROV is examined about the operating characteristics, image transmission, and remotely monitoring system. The temperature, conductivity, and turbidity of the sea surface are collected with accuracy.

Compact underwater vehicle with accurate positioning system

Currently a platform to investigate the underwater environment is required. In this paper, we propose an autonomous underwater vehicle (AUV) with an accurate positioning system. The positioning system is developed to be accurate enough to utilize the superior navigation ability of our AUV feature. The navigation ability is acquired by the variable vector propeller mechanism. The accurate positioning became possible by introducing two acoustic signals with different frequencies. The range data were obtained satisfactorily with maximum error less than 0.01m. Using the positioning system, the navigation trajectory of the AUV could be measured.