signal following

Descention

is it possible to have a robot follow a signal (assuming radio would have to be used), where the signal is not in direct line of sight of the robot and the signal moves (such as someone walking).

pretty much what im looking for is a robot that can follow a person, or goto a person, even when said person is not in sight of the robot, but person can be anywhere in house.

i am not sure where i would hav to start with this, but i know the robot would have to find the direction of the signal emitter, and a rough distance to travel. obstacle avoidance will come later.

thanks

PJAllen

· If you were using audio or ultrasonic to Call with, you could make a routine to move a parabolic (very directional) microphone with a motor/servo to sample and to home in on the Call.· You'd need an omnidirectional that could hear the Call which would cue the directional search to begin.· Once it determined where the Call got the loudest response it could move in that direction somewhat and start the sample/search routine.· [noparse][[/noparse]Listen, Analyze, Move, Listen, Analyze, Move,...]

· You'd want to use a special tone (like a DTMF or something modulated?), eventually, but to get started with your research you could begin by using a single frequency.· Afterall --·you want it to specifically home in on your Call (beacon) and·not just any ambient noise/sound-level (which'd be dopey.)


Post Edited (PJ Allen) : 6/22/2006 1:44:34 AM GMT

Chris Savage

As far as I can tell, the only way you're going to be able to do this if the person is not line of sight, like on the other side of a house is to have a GPS receiver on that person and transmitting the coordinates to the Robot via RF transmitter.· The robot would also need a GPS so it knows it's relative position and can navigate based on that information.· Of course you have to have other sensors.· You don't want to just try plowing through walls.


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Chris Savage
Parallax Tech Support
csavage@parallax.com

Descention

i like both ideas, but i think the GPS would probably be a little better (though probably more expensive) considering the whole wall/barrier to block or dampen sound and such. thanks guys. now i must do some research on GPS...

Franklin

If you can make it work indoors let us know. I've not seen any inexpensive ones that will. (yet)

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- Stephen

Mike Green

If you want this system to work in a particular space / house, you can put transponders (probably IR) in each room that can relay the "come here" message to adjacent rooms adding an identification byte for each room that relays it after checking for cycles (room to room to room and back to the same room). The robot can use the summons for navigation information to the destination room, then some line-of-sight mechanism within that room.

Descention

currently, i won't be able to do anything with work taking half of my time and saving up money for college tuition. im just trying to gather as much information as i can, and hopefully i can slowly gather all the things i will need.

this robot would not only be used in the house, but for entertainment, to follow me around outside my home. one place i wanted to take it with me would be a rennaisance faire (if they'd allow it), and dress up the robot as a pet dragon. it would follow me around, and avoid hitting people by detecting them with multiple sensors (IR, sonic, motion detected by camera). it's gonna be a long project for me, but it gives me something to learn from.

Mike Green

You can probably use a modulated IR beacon that you wear on a hat. Something like a BOE-BOT with the PING sensor and bracket, IR-LEDs for short range object detection and another modulated IR sensor on the PING sensor bracket for tracking the beacon would be a good development platform. You could remount everything later on a platform better suited to look like a pet dragon (and balanced for the task) with a movable head with the sensors in it.

MachineMonkey

That's interesting. I like the IR transponder idea; here's another: radio receivers at 4 corners of the house all keyed to a single freq and ID (linx LR chips would be great), all receiving the 'go' signal at different times, depending on the distance (and obstructions ) between the target and the Rx. Each Rx feeds 'hit' timing to a central Stamp which uses a lookup table to chart the Tx position using known (calibrated) positional interpretation. This Stamp uses another Linx set to give that location (and the go siganl) to your rover. The rover, using the known dimensions of your house (or pre-programmed routes from each room to every other), uses onboard sensors to navigate the temporary obstructions (moved furniture, household pets, closed doors, stairs) in its known path to the target's last reported position.

- K

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Failure is not the only punishment for laziness; there is also the success of others.

- Jules Renard

Brian Joly

I have been programming web sites·for about 5 years and toying with radio controlled vehicles since childhood.·It wasn't until I read about the DARPA Grand Challenge that I become interested in robotics.· I would like to start out with a Boe-bot to get an understanding of robotics and then later install the electronics into an RC car, boat, or airplane chassis and set it up for autonomous waypoint navigation and obstacle avoidance.· GPS, camera, compass, ultrasonic, infrared, tilt, and bump sensors·could be used to gather the necessary data to navigate the course. I would also like to integrate some kind of long range telemetry to feed sensor data to a ground station.· I'd like to know how to integrated GPS with the·Boe-bot electronics and perhaps an RF modem or similar to send and receive commands from a ground station PC/laptop.· Any suggestions or recommendations would be greatly appreciated.

Best Regards,

Brian Joly

A.C. fishing

It sounds like you need a bigger version of the IR beacon at www.pololu.com

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Somebody said...
-Never Underestimate the power of human stupidity.

·

Szarzynski

Here is one solution to your problem:

http://cricket.csail.mit.edu/

A neat idea that uses the difference b/w the speed of sound and the speed of light to determine the distance from beacons. I figure that if you put a 'listener' on both the bot and the person they can transmit thier location to one another and the bot can navigate accordingly.