Mashable - Tech This smart luggage automatically stays by your side.
Alex Libman NUA Robotics, Israel
This uses what my circle of friends were calling a "Follow Me" system or circuit.
There are a number of ways to solve this using sensors, and video.
Some range from slightly complex or expensive hardware that would work excellent, to struggling with low cost sensors that just don't provide much information.
On my other blog I write about to Robotic Golf Caddies that also Follow operators around.
Caddy trek vs. Shadow Caddy
Shadow Caddy used 300khz rf Radio Direction finding while Caddy trek uses low cost Ultrasound transducers.
Then there is the Five Elements Robotics, Budgee a robotic shopping cart that automatically follows you around
This one is also Ultrasound based and the only one I've tried personally and found it not quite ready for prime time.
I have also seen this done using Lidar, 3D Depth Cameras.
Using a thermal camera like the FLIR would also work well, check out this Heat Tracker I worked on.
It's alway been my feeling that using some sort of transponder which is what every caddy and shopping cart used is probably the correct approach when combined with Lidar or some other form of obstacle / collision avoidance.