chrisp@bilby.cs.uwa.oz.au (Christopher Pudney) (10/09/90)
Dear Comp.Roboticist, We are interested in eqipping a manipulator with some sort of proximity sensing and would be grateful for any advice from persons who have used proximity sensing of one sort or another. Ideally we are looking for a sensor which will be able to provide the direction and distance to the nearest object (Knock/touch sensors would be considered a last resort). If you have any information you think we would find helpful, please don't hesitate in letting me know. AtDhVaAnNkCsE. -------------------------------------------------------------------------------- Chris Pudney Department of Computer Science, PHONE: (local: 09) (int'l: +61 9) 380 3455 University of Western Australia, Nedlands, Western AUSTRALIA, 6009. FAX: (local: 09) (int'l: +61 9) 382 1688 E-MAIL: chrisp@wacsvax.cs.uwa.oz.au -- -------------------------------------------------------------------------------- Chris Pudney Department of Computer Science, PHONE: (local: 09) (int'l: +61 9) 380 3455
mgobbi@cs.ubc.ca (Mike Gobbi) (10/10/90)
Have you considered using sonics? It shouldn't be that hard to broadcast
a narrow beam of sound and wait for the echo. If the speaker-mike is on
a rotating boom, you can tell what angle (relative the the robot) the object
is at. It may even be possible to determine the size of the object based on
the volume of the echo (with the delay giving the range).
I seem to recall that there are surveying instruments on the market that you
simply point at a target and they digitally read out the range. One of these
could be connected to a hardware interface fairly easily as well (I think).
I'm not a robotics person, so forgive me if this idea is way out in left
field.
--
__
/..\ In quest of knowledge....
--mm--mm-- Mike Gobbijpexg@wheat-chex.ai.mit.edu (John Purbrick) (10/10/90)
> We are interested in eqipping a manipulator with some sort of >proximity sensing and would be grateful for any advice from persons who >have used proximity sensing of one sort or another.... >Chris Pudney >University of Western Australia A few years ago I saw a film brought by a guy from your very institution, about a robot sheep shearer. The cutter head "flew" over the animal's body using capacitive sensing (the sheep was grounded). It was claimed to work well, but perhaps it didn't really perform under realistic conditions. Optical sensors always appealed to me more anyway. John Purbrick jpexg@ai.mit.edu
mwtilden@watmath.waterloo.edu (M.W.Tilden, Hardware) (10/16/90)
In article <chrisp.655433520@cricket> chrisp@bilby.cs.uwa.oz.au (Christopher Pudney) writes: > > We are interested in eqipping a manipulator with some sort of >proximity sensing and would be grateful for any advice from persons who >have used proximity sensing of one sort or another. Ideally we are >looking for a sensor which will be able to provide the direction and >distance to the nearest object (Knock/touch sensors would be considered >a last resort). > > If you have any information you think we would find helpful, please >don't hesitate in letting me know. At the recent North American Micromouse championships (see forthcoming article for details), I was impressed that Bill Ottman's mouse used infra-red LEDs and focused IR detectors to successfully distance objects as far as 4 inches away. The output was amplified and fed into a ADC which then fed a look up table for true luminosity/distance correlation. Of course, you have not specified the scale of your implementation. How large is your manipulator field? Is all. -- Mark Tilden: _-_-_-__--__--_ /(glitch!) M.F.C.F Hardware Design Lab. -_-___ | \ /\/ U of Waterloo. Ont. Can, N2L-3G1 |__-_-_-| \/ (519) - 885 - 1211 ext.2454, "MY OPINIONS, YOU HEAR!? MINE! MINE! MINE! MINE! MINE! AH HAHAHAHAHAHAHAHAHA!!"
chrisp@bilby.cs.uwa.oz.au (Chris Pudney) (04/26/91)
G'day, I am working on a collision prevention project for our U.M.I. RTX robot arm. The arm has a reach of approximately 1.3m (~4.25ft) and a stopping distance of the order of a few centimetres (a few / 2.54 inches). Collisions will be prevented by sensors mounted on the arm that alert the controller when an obstacle is approaching the arm's stopping distance. The controller then halts the arm before collision with the obstacle can occur. I have considered using ultra-sonic sensors (such as the Polaroid sensor), but have read that this sensor behaves poorly for distances less than 30cm (~1ft). Active damping of the transducer can improve performance for such distances. Also in order to completely protect the RTX arm would require a number of sensors. They cost about $500 each here. Alternatively, I could use I-R sensors. These sensors operate well at distances under 30cm (~1ft) and are less prone to specular reflections than ultra-sonic sensors. They are however affected by surface colour and have a fairly narrow beam width (so I may literally have to plaster the arm with sensors to completely protect it). Again cost may be a limiting factor here. I would appreciate any information (operating ranges, prices, problems etc.) you have that would help me choose a sensor suitable for the task outlined above. Stories of proximity sensors you have used are also welcome. AtDhVaAnNkCsE. -------------------------------------------------------------------------------- Chris Pudney Department of Computer Science, PHONE: (local: 09) (int'l: +61 9) 380 3455 University of Western Australia, Nedlands, Western AUSTRALIA, 6009. FAX: (local: 09) (int'l: +61 9) 382 1688 E-MAIL: chrisp@cs.uwa.oz.au -- -------------------------------------------------------------------------------- Chris Pudney Department of Computer Science, PHONE: (local: 09) (int'l: +61 9) 380 3455
espiau@alcor.inria.fr (Bernard Espiau) (04/29/91)
See: `Use of Optical Proximity Sensors' by B. Espiau in `Recent Advances in Robotics', edited by S. Hackwood and G. Beni, John Wiley & sons, New York, january 1985; and also: `Collision Avoidance for Redundant Robots with Proximity Sensors', by B. Espiau and R. Boulic, Third International Symposium on Robotics Research The MIT Press, 1986