Our Vessel

Topcat

TopCat is an electrically powered autonomous surface vessel that carries a range of advanced sensing equipment. The vessel uses the suspension system on the WAM-V platform to provide a stable base for the sensor suite and power systems.
Five metres long with a cruising speed of around 4 knots (8 km/h) and a cruise endurance close to 5 hours, TopCat is well suited to monitoring tasks in hostile conditions or protected areas. The vessel is currently capable of mapping and monitoring tasks using the onboard Lidar and Radar systems. Additional sensors can be attached via the underwater deployer to perform specific tasks such as sea bed mapping or environmental surveying.

User Interface

A key part of developing unmanned vehicles is ensuring an easy to use and reliable user interface. Developing a system which both provides sufficient information for systems analysis while allowing non technical researchers to easily view data has been a focus for us.

Our user interface consists of a base control station which relays system information and safety data to the mission supervisor as well as a web based data interface which allows users to access and visualise only the data relevant to them.

Software

The software which runs Topcat is based on the Robot Operating System (ROS). ROS is a collection of open source software libraries and tools which enable rapid development of robot software infrastructure. On top of this backbone we have developed multiple algorithms including object recognition and classification, mission planning, navigation and control systems. These systems allow Topcat to autonomously plan and execute given tasks such as mapping a selected area.


Hardware

Topcat's hardware is a combination of off the shelf parts and custom built systems. The focus for the overall hardware design was stability, reliability and modularity to allow safe, easy operation and upgrades. The vessel is a stable inflatable catamaran platform powered by electric motors and large batteries. This hardware setup provides a reliable and easy to use platform to develop and test our software algorithms.

WAM-V

Topcat is based on the wave adaptive modular vessel (WAM-V) platform developed by Marine Advanced Research. To this platform we have added a sensor mounting array, an underwater deploying arm, a battery cradle and two neutrally bouyant motor modules, allowing Topcat to operate safely in the open ocean.

Propulsion

Topcat is a fully electrical vehicle powered by two Torqeedo Cruise 2 electic outboard and two large Kokam lithium polymer batteries. A steering system has been added to ensure high maneuvrability of the vessel in all conditions.

Electronics

Topcat uses a main electronics distribution box which contains power regulators, network switch, USB devices and microcontrollers. This connects to all the sensors and provides the interface to the computer, housed in a separate box.

Communication

Communication is critical for safety and reliability of the system. Topcat uses long range, low power 900MHz communication for teleoperation, telemetry and safety communications as well as long range 5GHz WiFi for data and video streaming.


Sensors

Topcat carries a broad selection of on board sensors. These sensors are mostly used for navigation, control and obstable avoidance however they can also be used for mapping above and below the water. Additionally, mission specific sensors can be easily integrated as required.

LiDAR

Topcat carries a Velodyne HDL32E LiDAR. This sensor is capable of providing a precise 360 degree volumetric scan of the area up to 100m away. It is the primary close range obstacle detection sensor.

Radar

Topcat also uses a low power Simrad 4G Radar system for longer range obstacle detection and coastal mapping. This system can detect larger obstacles up to the horizon and is useful in offshore operations.

GPS

Topcat uses a dual antenna Trimble BX982 GPS system for position and heading. This system when used with an RTK basestation can provide sub centimeter accuracy.

Sonar

For underwater sensing capability Topcat carries a Tritech Super SeaPrince mechanically scanning sonar. This can be used for underwater object detection and seabed mapping.

Wind

Topcat is a very light vessel and wind affects can be significant. It carries on board an ultrasonic wind speed sensor to allow the software systems to compensate for wind in real time.