Open sorce Propeller CNC controller
Hi All,
This whole propeller cnc has been rolling around in my head for awhile ,I have read alot of post about it but we need to start from scratch and build a good one.
The first thing we need is a object that can call 1-4 cogs to control step and direction of each axis (step and direction drives will work from really cheap steppers to big ac servo's). The way I see it is that each cog can have one counter controling the step while it is getting the data for the next move.
the cog should be started up with info like: axis data (x.y.z.a),backlash ,max speed,steps per inch,direction marker,and where the next move data is stored in the hub.
I think if we start from the bottom and work up we can build a contoller that will work on any machine.
Brian
This whole propeller cnc has been rolling around in my head for awhile ,I have read alot of post about it but we need to start from scratch and build a good one.
The first thing we need is a object that can call 1-4 cogs to control step and direction of each axis (step and direction drives will work from really cheap steppers to big ac servo's). The way I see it is that each cog can have one counter controling the step while it is getting the data for the next move.
the cog should be started up with info like: axis data (x.y.z.a),backlash ,max speed,steps per inch,direction marker,and where the next move data is stored in the hub.
I think if we start from the bottom and work up we can build a contoller that will work on any machine.
Brian
Comments
if the axles should move synchronised you have to create step and direction signals in just one cog. Otherwise it will run out of sync.
This is no problem even for high pulserates when using PASM. There is an algorithm called Bresenham-algorithm which can create
XYZ-pulse ratios meaning X : Y 1 : 4.56782 : 2.65789 or any other ratio only by calculating sums and differences. No multiplication nescessary.
This algorithm allows to create the step-pulses for each axle within one single loop. This makes 100% sure that the pulses stay in sync.
I'm thinking about a controller-concept where the controller can drive steppers servos and and AC-async-motors. I'm just at the beginning
so I do not know yet what comes out.
I want to do this in collaboration with the http://opensourceecology.org/wiki/Open_Source_Stepper_Motor_Controller
How about working together with them?
keep the comments coming
best regards
Stefan
I've seen some nice efforts from you ,Ken Bash and Graham Stabler. I was just testing your mini cnc code today but could not get the steppers to move very much.I would be more that happy to work together on this.
Here is a screen shot of my milltronics mill , I would like the prop controller display to look similar.
Brian