Chad Fraser for The Street:  Soon, robots could be doing much more than just vacuuming your house or assembling your next car-they could also invade your investment portfolio. If you're looking for the industry's fastest growth, you'll want to pay particular attention to what's happening on the consumer/office side, where sales are set to grow at a 17% compound annual rate between 2014 and 2019, according to a May report from Business Insider -- seven times quicker than the industrial-robot market. In addition, a number of radical new applications for robotics are emerging in the medical and defense markets, as outlined in this presentation from Investing Daily.

Even though the automation trend is clearly set, there still aren't many pure ways for investors to play it. But that doesn't mean there are no intriguing options out there. Here are five robot makers to keep on your radar screen: