ross@ecr.mu.oz.au (Ross McAree) (11/20/90)
I'd be interested to hear comments on available VME based servo-motor controller boards. I'm looking for anything that will output a +- 10 volt motor command signal, perform quadrature decoding from HEDS style encoders, and have some programmable filtering capabilities. I'm familiar with the GALIL DMC-300-10 which fits my requirements but at the same time has some awful features, for example its instruction set is ASCII based and it doesn't generate interrupts. I understand that the Lynx OS people have a controller board but I don't know anything more about it. Is anyone using this board? What other boards are available? I'll summarise if there's sufficient interest. Ross McAree, Robotics Laboratory, University of Melbourne. Parkville, Melbourne, Australia. 3052.
gerry@frc2.frc.ri.cmu.edu (Gerry Roston) (11/20/90)
Someone hits a sore spot! Unfortunately there is a dearth of GOOD VME based motor controller boards. A quick summary follows, obviously, there is a bunch of personnel prejudice: GALIL: Crap. Uses ASCII, etc. CREONICS, Ver 1: Crap. Uses byte transfer. Also, very difficult to talk with card. Each transfer requires several interrupts, reads, writes, etc. I have written a really sweet VxWorks device driver for these, but there is no way to prevent things from screwing up if multiple interrupts near simultaneously. CREONICS, Ver 2: Crap? Supposed to fix bugs in Ver. 1, but I understand that it is very buggy. This may have been fixed. DELTA TAU DATA: Has a bunch of nice features, but is also limited by ASCII data transfer. Generates too many interrupts (?) PRECISION MICRO CONTROL: My current choice. Uses 32 bit word data xfer, supports interrupts (although maybe not flexible enough), and can have up to 6 axes per board. A device driver should be real easy. COMPUTER MOTION INC - 3DP: Looks super cool! Goes in backplace of a Sun, is screaming fast, and costs only $20,000. Seriously! Creonics Inc Etna Road Lebanon New Hampshire 03766 603-448-6300 Delta Tau Data Systems 21119 Osborne Street Canoga Park California 91304 818-998-2095 Precision Micro Control 3555 Aero Court San Diego California 92123 617-576-8058 Computer Motion Inc. 475E Cannon Green Drive Goleta California 93117 805-685-3729 -- gerry roston, field robotics center robotics institute, carnegie mellon university pittsburgh, pennsylvania, 15213 (412) 268-6557 gerry@cs.cmu.edu
cb1p+@andrew.cmu.edu (Chris Beasley) (11/26/90)
2 suggestions for motion control revolve around what you want to do. We have used Creonics boards and been trying to replace them with a solution of our own. In our experience the Creonics was not sufficient for what we were trying to do: Control a six axis manipulator whith (slightly) unusual dynamics. The Creonics would have been wonderful for a process automation environment with less dynamic constraints. For high performance applications I would reccomend the new DSP based multi-axis MC board from Delta-Tau motion controls. This seems to be able too control many different types of motors and several different types of amplifiers and feedback. Dual ported memory is the interface (as with the Creonics). The board has some facility for digital filtering and I think you can also modify the control law structure somewhat (I don't have the info yet). If you want to have a more detailed conversation about optimal control systems you should tell us a bit more about your application. CB