Liquid Robotics, a Silicon Valley startup, has raised a $22 million round of funding to expand its fleet of self-propelled, solar-powered, ocean-going robots. Called Wave Gliders, the robots currently are roaming the worlds oceans to monitor oil and gas wells, keep tabs water quality in the Gulf of Mexico and gather data on the melting of Arctic icecaps, according to Bill Vass, Liquid Robotics new chief executive. These Roombas-of-the-sea deploy fins that tap the up-and-down movement of waves to propel themselves through the ocean while solar panels power the Wave Gliders sensor and communications arrays. The base model costs $100,000 and Liquid Robotics has deployed nearly 100 Wave Gliders over the past year-and-a-half that have racked up 150,000 miles of ocean travel, according to the company.