Riverwatch uses robotic symbiosis to study waterways


February 11, 2014

The Riverview system is a symbiosis of two robots – an Autonomous Surface Vehicle (ASV) and Unmanned Aerial Vehicle (UAV) visible on the back

The Riverview system is a symbiosis of two robots – an Autonomous Surface Vehicle (ASV) and Unmanned Aerial Vehicle (UAV) visible on the back

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The string of disastrous floods currently plaguing Britain demonstrate that managing rivers and other waterways is about more than protecting curlew nests and counting otters. To help provide a better understanding of riverine areas, a team headed by José Barata and Pedro Santana of the University of Lisbon is developing a “marsupial” robotic system called Riverwatch that teams a robotic catamaran with an on-board hexacopter to survey areas beyond the reach of the hip-boots and rubber raft brigade.

Rivers, swamps, broads, marshes and similar soggy environments are vital to understanding local ecology, protecting against floods, and sorting out proper water management. Unfortunately, they are surprisingly difficult to survey. As anyone who’s been stranded thanks to a weed-snarled propeller can tell you, many areas are horrible places filled with reeds, muck, mud, bugs, leeches, and ghastly smells.

One solution to this is to use remote sensors, such as onshore, installed on buoys, or mounted on poles. This has been a partial solution, but fixed sensors can’t provide much in the way of detail and they can’t always collect samples where they’re needed. A robot would be ideal, since it isn't bothered by mosquitoes and can be designed to handle shallow water and mud. However, robots are hard to navigate because they can’t see much – especially in cluttered streams with their sensors close to the water.

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 that of an Unmanned Aerial Vehicle (UAV).

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

Riverwatch is controlled by means of a web-based application that operates in one of two modes. For line-of-sight distances of less than one kilometer (0.62 mi), the control uses a direct wireless link. For longer distances, the link is over the internet using GPRS or 3G using a file-sharing system, such as DropBox.

Field trials for Riverwatch were conducted at a private lake in Portugal’s Sesimbra region, where the two robots were tested in autonomous and tele-operated modes over an area of about 1.5 square kilometers ( 0.5 square mi). The area was chosen because of its variety of vegetation environments from overgrown, shallow passages to wide-open expanses of deep water.

According the the Riverwatch team, the next step in the program will be to develop a fully autonomous system that can charge the UAV from the ASV, conduct a full evaluation of the landing algorithms used by the hexacopter, and develop a recovery mechanism to allow the UAV to land in bad weather.

The video below outlines the Riverwatch program.

Source: Riverwatch

About the Author
David Szondy David Szondy is a freelance writer based in Monroe, Washington. An award-winning playwright, he has contributed to Charged and iQ magazine and is the author of the website Tales of Future Past. All articles by David Szondy

I think it would be cheaper to use an airboat or paddle wheels.


Like Slowburn, I am sure that other, simpler solutions can be found. It is not obligatory to follow fashion, the use of ****copters as a cure-all being the latest manifestation of the practice.

Mel Tisdale

It's not the rivers that are the problem guys, its the $£billions we pay to farmers to clear drain and graze lands upstream. Stop the US & EU farm subsidies and farming would move off the uplands. We are currently handing our taxes to governments, who are handing them to farmers to flood our homes. All a bit silly really.

Doug MacLeod

As this platform is out patrolling, what keeps someone from "kidnapping" it and holding it for ransom?


@Doug Macleod, it was not the farm subsidies which caused the UK flooding, but 20 years of delegating by law flood protection management to a quango which spent only £20 million per year on flood management for an entire country, mostly on publicity campagins, it scrapped the dredger fleet it inherited and spent the rest on itself and environmental lobby pork on an annual budget of £1.5 billion. It actually spent more on prosecuting riparian tenents who tried to fulfill their tenent obligations by clearing rivers of debris and building banks than on flood prevention but managed to have a combined staff of 12,500 who by performance were paid handsomely to sit in an office until their pension cheques came through.

Quangos (quasi-autonomous non-governmental organisation) in the UK they are effectively privatised Government so instead of the usual tax churning effort to emply white collars staff for life on other peoples money, it is employing white collar staff for life on other peoples money with additional profit motive. So unfortunate that it is that such organisations are not in fact Government therefore covered by crown immunity from prosecution for damages caused by fraud, neglect of contract and deliberate damage to property.

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