Barbara Block, Stanford University – using SV2, Plans for SV3
Last December, Liquid Robotics made headlines when one of its Wave Glider aquatic robots completed a “swim” from San Francisco to Australia. It marked the longest distance ever traveled by an autonomous vehicle of any type. The research/surveillance robot was part of a fleet of four that took part in the demo project. One of the others successfully reached Australia later, while the other pair are still on their way to their alternate destination of Japan.
Besides making the much-publicized PacX trans-Pacific crossing, the company’s “base” model of the Wave Glider (the new version of which is now known as the SV2) has been used by a variety of clients in a number of different projects, since its launch in 2009. “We’ve built over 200,” Liquid Robotics CEO Bill Vass told us. “About a third or so are on missions at any one time. A lot more customers are moving to running 20 at a time instead of one at a time…”
Monday, the company announced its SV3 – the new-and-improved version of the existing Wave Glider robot. Like the SV2, the SV3 consists of two main parts that are tethered together.
On the surface is a floating surfboard-like “boat,” that contains the sensors which allow the robot to measure oceanographic data such as salinity, water temperature, wave characteristics, weather conditions, water fluorescence, and dissolved oxygen. Also on board are a GPS unit, a heading sensor, transmitters/receivers and other electronics – all of which are powered by built-in solar cells. Below the surface is a winged platform that catches the underwater motion of the waves, allowing it to paddle itself forward, along with the tethered boat…
More intriguingly, however, the SV3 additionally features a thrust-vectoring electric motor. Its propeller folds out of the way when not in use, but can be lowered and activated (either autonomously or by satellite remote control) when the robot needs an extra push – such a push might be helpful if it encounters doldrums or cross currents, or if a sudden change in its route is required. The motor is powered by a battery that is in turn charged by the solar cells, as with the other electric components.
Solving the problems of autonomous function and durability are the hard bit. Hardware, that is. One of the smartest things they’ve done in the software is designing in a system that can diagnosis a problem that may hinder mission completion – whereupon the Wave Glider changes course and heads for the nearest repair facility. Phoning home about the problem, of course.