Visiting guest. Why not sign in? |
News, knowledge and discussion for the AI enthusiast.
FEATURES |  | COMMUNITY |  | KNOWLEDGE |  | SEARCH |
Get Creative: AI Article Writing Contest Fancy the chance of getting developer focus, improving your research skills, sharing your artificial intelligence ideas, obtaining expert feedback, getting published online AND winning a prize? Enter the AI Article Writing Contest! |

Visually guided reaching Reaching for nearby objects
Visually guided reaching One useful task for a humanoid robot is to be able to reach towards objects within its immediate vacinity and try to grasp them. Physical manipulation helps the system to learn about the properties of objects, and to determine whether the object is passive (inanimate) or active (animate). Rodney doesn't have any hands or pressure sensors yet, but I've been trying to get him to reach for objects which are close to the cameras. For this task the physical structure of the robot allows some crude shortcuts to be taken. When rodney observes moving objects his cameras pan and tilt to try to maintain the object within the centre of vision. When rodney's cameras are tilted downwards they can only view a limited area within the immediate vacinity of the robot, so its safe to assume that any movement observed is within close proximity. One of the arms is then moved to try to intercept the object, using the already calculated centre of motion value to guide it into the right area. This seems to be a crude but effective mechanism allowing the robot to reach for objects. A more sophisticated method would be to use the stereo matching to calculate distance and shape more accurately. - Bob http://www.fuzzgun.btinternet.co.uk/rodney18.jpg | motters 136 posts. Saturday 05 January, 19:01 Reply
Cunning! > When rodney's cameras are tilted downwards they can only view a > limited area within the immediate vacinity of the robot A truly ingenious way of determining the distance ;) Stereoscopy would be expensive though... It might be worth having a few sonar sensors, but I don't know how much they're worth. | Alex J. Champandard 935 posts. Wednesday 09 January, 04:25 Reply
Wither ultrasonics? I do actually have a set of six ultrasonic sensors from an earlier (now defunct) robot. It's quite possible that I could use these on Rodney, but I'd prefer to keep the system simple and efficient if possible. I think approximate distance measurement should be possible with stereo vision, and this is the approach I'll be following. If the problem turns out to be absolutely insoluble only then would I resort to using the ultrasonics. - Bob | motters 136 posts. Wednesday 09 January, 13:37 Reply