Hi all, I have a crazy question. I would like to build a large custom arm and use RIOS and the ssc-32 board to control it. However I would like to use normal dc motor with encoder or pot feedback, (so as to have more power than hobby servos allow) I googled and found several places selling motor drives that can take rc inputs and turn a dc motor into a “giant servo” One such company is Gamatronix. The mechanicals will not present much problem as I am a machinist. The motor drive wiring and such is even in my capabilities, however the software is not. Hence the desire to use RIOS. I guess RIOS would feed signal to ssc-32 which drives gamatronix motor board with drives dc motor with feedback? Is this possible or am I nuts? If nuts are any of you software wizards interested in writing a program similar to RIOS but for dc motors or stepper motors?
Thaks
Dan
Below is a recent discussion about using larger motors. The tough issue I see is working out how to specifically control the large motors. I don’t think the programming would be an issue. I’ve got some ideas on using a $10 servo to be the pilot controller for larger motors, but just haven’t had the time yet to work on it.
Thanks for the reply. On my cnc milling machine I run motor drivers from a place called geckodrive. It can handle 20 amps. I planned on using motors rated for less than 20 amps and running them thru a harmonic drive. Basically I then need speed not torque (or not as much torque anyway) I would love to use the geckodrives however they only accept step and direction inputs not rc signals. So my problem is how can I get a arm control program to interface with a “normal” dc motor or stepper motor? There seems to be numerous hobby cnc programs for driving stepper drives from the pport, why can’t one do the same for a program similar to rios? If only I could program!!!
Thanks
Dan
Hi Dan,
I wrote a control program for my CNC’d Sherline Mill and lathe. I too use Geckos!
If you want to control an arm with steppers, why not just use CNC then? I have been thinking about doing just that for the interpreter part of a control program for Loki, my 4-servo biped. Only after getting the “angles” from the Gcode parser, I’ll issue R/C servo commands instead. Fixed walk sequences will be selected as Gcode “subroutines”. My controller program (STEP4) has loops, branches, math, variables, etc. Anything else I want, I can add.
I run my controller program in DOS because of the tight control of the pulse stream needed for steppers. I should be able to port the parser and move calculation modules over to a PIC. No need for a UI, or built-in editor, although they would be nice.
Look up the CAD_CAM_EDM_DRO list for more CNC stuff. or my SherlineCNC list.
Alan KM6VV
Alan, thanks. I have seen your name many times in the cad cam edm forum also on cnczone I think?You bring up a great point, why not just cnc the arm. Please rember you have forgotten more about programming than I ever knew!!! I currently use turbocnc or mach3, depending on machine. I have looked into emc for the robot arm, just seems confusing to me. The arm I would like to build can be tethered to a pc, no problem. I have to admit I am a bit lost on how to use gcode to control it without doing alot of expermental moves, ex: at what location will the gripper be at after each move. I also like the idea of using a joystick to teach the robot, like RIOS can. How would you convert gcode into defined motion short of expermenting? I know industrial robots have such a program, gcode to robot control, I just have a few zeros short of that budget.
Thanks
Dan
Hi Dan,
Yeah, I’ve been around on several lists. EMC has been made partially for robotic control. I haven’t used it for that, and don’t use it much as I have my own CNC controller program, and Mach3 also, if I want to use it. It’s more fun to use a program you yourself wrote!
I’m not sure what all EMC supplies for robots. It has jog keys, I know. In my program, I can turn on a “log file” and save the moves I’ve made with MDI (manual data entry) or the jog keys. this should be fine for “teaching” a 'bot.
In my case with Loki (biped), I don’t need to “teach” my 'bot much, I can generate a walk gait with a loop and about 6 or 7 states. I’ve already made him walk that way! Add a few more subroutines for turns, and I think walking is covered. That leaves the remainder of the interpreter to do the other “robot” stuff. I will have to add a little more “sensing”, but I do have some already. All easy if you have the 'code.
TurboCNC and CNCpro source code is also available, with ‘pro being free (and in C), and Turbo’ being quite reasonable. I have both. My controller is in C, of course.
I have an arm I built a long time ago that uses about 6 stepper motors. I should probably get around to running that with my CNC controller too!
Let’s give this some more thought! RIOS being able to use a joystick is great, but I’ve tried moving around the mill’s axis with a joystick, didn’t like it much.
Do you mean how do you write Gcode short of experimenting? If you’ve got sets of coordinates from a “simulator” program, then you can almost “cut and paste” the coordinates into a Gcode program. Just need to stick in the axis numbers… ;>)
Alan KM6VV