Grey Duck
Grey-Duck is the KAIST USV for the competition. It was built on a 16' WAM-V USVx by Marine Advnaced Research and the vehicle is provided by the AUVSI Foundation and ONR. It's dimension is 390cm in length, 250cm in width, 130cm in height and the maximum payload is 136kg.
< Fig. 1. Electric schematic diagram of Grey-Duck>
The Grey-duck USV system (see Fig. 1) consists of five parts: 1) propulsion system, 2) sensor system, 3) computer system, 4) power system and 5) emergency system.
(1) Propulsion System
The USV has a catamaran hull form, and thus two electric outboard thrusters are installed as a main propulsion system. The USV can be steered using differential thrust. In addition, two bow thrusters are installed in the fore part of the twin hull for improved maneuverability.
(2) Sensor System
For navigation, the USV is equipped with an integrated GPS/IMU system to estimate the pose of the USV. Specifically, a GPS compass (V102) by Hemispher GNSS and a MEMS IMU (3DM series) by MicroStrain Sensing Systems are used.
In addition to navigation sensors, the USV system is equipped with a monocular camera, two lidars (SICK and LEDDAR) and hydrophone arrays for exteroceptive sensing. The monocular camera and the lidars are mounted to the front of the main deck plate and used to detect and identify various features and structures on the water surface.
To find the location of a sound source, four hydrophones are installed on the lower hull of the USV, two on the starboard side and two on the port.
In addition to navigation sensors, the USV system is equipped with a monocular camera, two lidars (SICK and LEDDAR) and hydrophone arrays for exteroceptive sensing. The monocular camera and the lidars are mounted to the front of the main deck plate and used to detect and identify various features and structures on the water surface.
To find the location of a sound source, four hydrophones are installed on the lower hull of the USV, two on the starboard side and two on the port.
(3) Computer System
The onboard computer system is physically separated into two parts to distribute the potentially excessive computational load, and two industrial PC’s (Advantech ARK series) are used. The primary PC deals with control, navigation and task management, and the secondary PC takes charge of processing camera and lidar measurement. These two PC’s are connected via a TCP/IP communication link.
(4) Power System
Two standard car batteries in series are used to provide the 24V DC power. In order to reduce the any noise issue, the power system for the propulsion is separated from the sensor and computer systems. The capacity of the USV power system is approximately 1920 Wh. The duration is expected to be over 4 hours, but it may vary with operating conditions.
(5) Emergency System
The USV is equipped with two emergency switches which consist of a remote circuit breaker and two manual switches on the USV to release the power of the thrusters. The emergency system can be activated by a remote controller by physically disconnecting the power to the thrusters.
Orange Duck
Orange-Duck is a small USV platform which was developed to test and evaluate various algorithms for achieving the mission tasks before applying the algorithms to the much larger Grey-duck USV. Orange-duck is equipped with basically the same sensor suite as Grey-Duck. The Orange-Duck is less than 2m long and weighs less than 40kg. This allows us to conduct field experiments more easily and efficiently.
