Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!swrinde!ucsd!ogicse!milton!brucec%phoebus.labs.tek.com@RELAY.CS.NET From: brucec%phoebus.labs.tek.com@RELAY.CS.NET (Bruce Cohen;;50-662;LP=A;) Newsgroups: sci.virtual-worlds Subject: Re: Cheap Force Feedback for VR? Message-ID: <12154@milton.u.washington.edu> Date: 2 Dec 90 00:09:18 GMT References: <12079@milton.u.washington.edu> Sender: hlab@milton.u.washington.edu Organization: Tektronix Inc. Lines: 68 Approved: hitl@hardy.u.washington.edu In article <12079@milton.u.washington.edu> almquist@cis.udel.edu (Squish) writes : > Limited (but perhaps effective) CHEAP force feedback: > How about modifying the datagloves (eventually a datasuit) so that limited > force feedback cues could be transmitted? The original design of the datagloves had this as an option, though none of the gloves I've tried had it. I've since heard (here in this newsgroup?) that the option was removed because of problems with UL approval for the electrical requirements of the feedback effectors, which were piezo-ceramic vibrators, as I heard it. > How? Could this work? Subdivide > the dataglove into segments - size would depend on the resolution you wish to > obtain. Of course, make sure that joints have been subdivided properly. Now > take each of these subdivision and make them into a small balloon so that > when inflated, the outer surface would remain semi-flat and the balloon would > inflate towards the users skin (I believe this could be done by using > materials with different strengths - ie. outer material is say heavy surgical > material and inner material is standard party balloon material via physics, > the inner material would expand first). NOW, attach to each individual > air pocket section a line to an air compressor (maybe an inert gas or liquid > would work best?). The computer would then control the compressor and > inflat/deflat each segment accordingly. Certainly using this scheme > restricted joint movement and the sense of touch (pressure) could be > obtained. I think this approach will work. I thought of a variant of it a few weeks ago when I was trying to figure out how to provide feedback of resistance to the bending of finger joints, so it would feel as if you were actually holding the magic VR wand in your virtual hand. In my scheme the balloons are flat pockets which lie across the joints. They would consist of a space between two layers of airtight plastic welded together at the edges except for a small hole where air can be injected. There is small plastic hose running from the hole to a small valve (maybe at the wrist), which either opens the hose to the atmosphere, or connects it to a source of pressure. If the valve is opened to let in pressure sufficient to stiffen the pocket, it gets harder to bend the joint. The amount of air involved in inflating or deflating the pocket needs to be kept small to make the operation rapid, which is why I chose a flat geometry. For the same reason, you want to keep the hose diameter small. As long as hose flow resistance is not too high, deflation will not be a problem in this application; as soon as you connect the hose to the air, the pressure of the finger joint trying to bend will force the air out of the pocket. For pockets over fingertips or palms, for touch and texture feedback, you could connect to an airsink instead of the atmosphere: a container kept pumped down to near vacuum. The increased pressure differential from the pocket to the sink will help force the air out. It might be possible to manufacture the glove out of two (or maybe more) layers of material with channels formed in them for the pockets and the hoses and the valve connections, a sort of pneumatic integrated circuit. The valves could be small benders, either piezoceramic or electrostatic silicon (in which case it might be possible to fabricate all of them on a single large chip and make the hose connections part of the case. The same chip could have all the control circuitry and a communication interface to convert all the I/O to a serial form, so a single two-wire cable could connect each glove to the computer. This would put all the electricity in one place and maybe make UL certification easier. -- ------------------------------------------------------------------------ Speaker-to-managers, aka Bruce Cohen, Computer Research Lab email: brucec@tekchips.labs.tek.com Tektronix Laboratories, Tektronix, Inc. phone: (503)627-5241 M/S 50-662, P.O. Box 500, Beaverton, OR 97077 Brought to you by Super Global Mega Corp .com