Messages in this thread | | | Date | Thu, 19 Apr 2007 17:38:05 +0200 | From | Jiri Slaby <> | Subject | Re: [RFC 1/2] Input: ff, add FF_RAW effect |
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Dmitry Torokhov napsal(a): > I have been thinking about this and I don't think that exporting motor > data is a good idea, at least not in case of Phantom driver. The fact > that there are 3 motors is a hardware implementation detail and it > is not interesting for general application.
Ok, so what about torques (despite it's still something like FF_RAW or motor descriptor)? It seems not to be so bad called effect name -- not only phantom uses torques on motors as an unit of force, for example I get this by quick googling: http://www.caip.rutgers.edu/~bouzit/lrp/glove.html They use there some motors with 14 torque values too, so the phantom isn't the only device which uses this approach.
> My understanding that the end result of controlling these 3 motors
Actually there is also a version with 6 motors :).
> is a force vector (I don't know if there is such english term, this > is a literal translation from russian) applied to user's hand.
Better say torques vector. You must compute a torque for each place from the 3d (or bigger) vector of forces in different way for each device that exists -- this means forces are not independent unit, torques are in the meaning of layer which doesn't care about what is connected above and below it.
> If we are interested in using FF API we need to come up with a way > to express this effect without exposing implementation details of > one particular device.
Still, torques are better named raw/motor values, which goes to the device and I'm sceptic about inventing something class-better than this.
regards, -- http://www.fi.muni.cz/~xslaby/ Jiri Slaby faculty of informatics, masaryk university, brno, cz e-mail: jirislaby gmail com, gpg pubkey fingerprint: B674 9967 0407 CE62 ACC8 22A0 32CC 55C3 39D4 7A7E
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