Robots have previously demonstrated remarkable adaptability and utility for working our oceans, harbors and large lake systems. But what about rivers, canal systems, marshes and other watery environments where lots of surveillance and water management are necessary?

A team from the University of Lisbon has come up with a unique robotic solution of water management specifically engineered for rivers, swamps and wetlands.

Team leaders, Jose Barata and Pedro Santana, call their system Riverwatch, which is a brilliant yoking together of the best of field robotics with that of UAVs or Unmanned Aerial Vehicles.

This new Riverwatch hybrid system, termed a ?marsupial? robotic system by the Lisbon-based team, combines a robotic catamaran with an on-board hexacopter to survey waterways and wetlands where a boat alone is unable to travel.

A better understanding of riverine environments comparable to those that spawned disasters like the 2011 Thailand flooding and current floods ravaging Europe are the types of calamities that Riverwatch is designed to help prevent.

Without a craft like Riverwatch these environments are surprisingly difficult to survey.

Remote onshore sensors, specialized buoys, or pole-mounted devices are only partially successful at water management. Riverwatch provides the missing, on-water dimension necessary for better surveillance and sample collection.

?Previous ways of getting around the navigation problem involved helicopters acting as spotters for the robot, but this is expensive and potentially hazardous. The Riverwatch solution is to create a sort of robotic symbiosis that combines the strengths of a surface vehicle with a UAV.?

Abstract of the Riverwatch program

?The RIVERWATCH experiment considers the use of autonomous surface vehicles piggybacking multi-rotor unmanned aerial vehicles for the automatic monitoring of riverine environments. While the surface vehicle benefits from the aerial vehicle to extend its field of view, the aerial vehicle benefits from the surface vehicle to ensure long-range mobility.

“This symbiotic relation between both robots is expected to enhance the robustness and long lasting of the ensemble. The hardware architecture includes a considerable set of state-of-the-art sensory modalities and it is abstracted from the perception and navigation algorithms from the Robotics Operating System (ROS).

“A set of field trials shows the ability of the prototype to scan a closed water body. The datasets obtained from the field trials are freely available to the robotics community.?

See attached paper (above): “On the design of a robotic system composed of an unmanned surface vehicle and a piggybacked VTOL”

Basic Riverwatch toolbox

Riverwatch consists of an Autonomous Surface Vehicle (ASV), which is basically a robot boat, and a UAV. The ASV started life as a 4.5 m (14 ft) Nacra catamaran with the hulls filled with PVC closed cell foam and carbon reinforcements added for rollbars and for mounting a pair of 2 bhp Haswing Protuar motors.

In addition, the ASV has visual and sonar sensors and a docking station marked with a large H to aid in aerial image tracking. The sensors allow the ASV?s onboard computers to match images and sonar readings against satellite images and other data to build a virtual map to fix its position and to plot navigation paths.

On the back of the ASV is a six-rotor UAV.

“This is able to take off and land from the robot boat and provides and extra pair of eyes to help the ASV fill in the gaps, so it can pilot more accurately and efficiently.
Though the idea was considered by the Riverwatch team, the UAV doesn?t take actual pictures as part of the survey.

“The UAV is a hexacopter using Virtualrobotix?s VR Brain 4, which was chosen because its open source, is equipped with a powerful microprocessor, and has six rotors instead of the typical four,” say the team.

According to Riverwatch, the extra rotors provide greater lift capacity and make the craft easier to control if one of the rotors fails.