I want to make a 3 axis serial industial robot with stepper motor.
I heard that the stepper motor doesn’t need to have encoder. but I don’t know how can control the velocity and the position by this kinds of motors.
is there anyone here know about that?
the reason to have an encoder on a stepper motor, or any motor, is because it is a measure of absolute position. once you establish the “home” position then you can certainly index stepper motors out and have a general idea of their rotational angle. with stepper motors in particular though if you exceed their torque specification they loose sync with the controller and you really have no direct way to regain position information. typically this means going full stop and slowly bring them back to an index postion where a sensor can establish either home or limit. If you are working on a table or xyz this isn’t so much of a problem however if you are talking an arm with the potential for joint restrictions or objects in it’s operating space that need to be avoided this is much more challenging.
stepper motor control is all software and there is an abundance of examples and products around the internet. the absolute easiest route is to purchase an integrated drive and controller so you can just send it parameters and commands to achieve the acceleration ramps, velocity, and position desired. if you have more time than money you can purchase drives only and do the calculations yourself. I strongly recommend a microstepping drive, ideally with torque compensation, as it will help you overcome more easily some issues such as the mechanical resonanance that occurs at low stepping rates.
some general information about stepper control follows. velocity for a stepper is equivalent to the frequency of step pulses. position therfore is the number of accumulated pulses from your index mark. your acceleration and deceleration ramps are determined by the rate that you change the step pulse frequency. unlike a dc motor that you can just full field and allow to reach some velocity based upon the motor, load, and current limits of the supply a stepper motor needs a programmed ramp for acceleration and, if there is enough inertia in the load, a programmed ramp for deceleration.
hi
thanks for your response.
My problem is that ,i can’t find a controller for 3 motor simultaneously.because of synchronization problem, i need a controller which is able to control the 3 axis or more,
have you ever use this kind of controller, or can you recommend me one of this controller.
at last
If I have 3 axis serial robot (like a common industrial robot).I wan to do a trajectory by my robot like writing some thing or following a curve.
do you think selection of stepper motor is a good solution to run my robot
instead of dc motor due to price and easy to control.
thanks in advance
Dude!
Just get one of these…
probotix.com/3_axis_stepper_ … iver_kits/
Control it with G-code Google it! and you’re basically done… 
thanks alot
have you ever use them? do you know a bout the precision of them, I mean precision to chang angular position.
Is the controller software ‘‘EMC2’’ user friendly?`easy to operate?
scincerely
Dude,
Please go to the website and ask him. His name is Len and he is a friend of mine. I’m sure he will be more knowledgeable than me!
Check on the CAD_CAM_EDM_DRO or SherlineCNC lists I mentioned. There are plenty of 3 or 4 axis stepper motor controllers available.
I’ve had good success with the Gecko drive modules I’ve mentioned.
Any of the CNC control programs I’ve mentioned will easily run 3 or more axis CNC systems.
You really need to shift your searches over to a CNC list!
Alan KM6VV
I am so thankful for all responce
Probotix has some nice stuff! And prices aren’t bad either.
That table-top router would work great for the PCB router I’ve been trying to get finished.
Yes, I think he just needs to shift gears over to either stepper or DC servo motors.
I’m using steppers on my mills and lathe. With a CNC controller program that generates step/direction signals from Gcode files, it’s easy to drive either type of motor with readily available motor drivers.
Alan KM6VV
Are you comfortable with Linux? EMC/EMC2 runs on Linux. You don’t have to know much about Linux to run the program, although it does tie up a PC unless you make it dual boot. I’ve got Linus and EMC on one of my machines, but I very rarely run it. I have a CNC controller program that I wrote (STEP4) that runs on DOS, and serves me quite well for my mill and lathe.
Setting up EMC2 might be a little challenging. Find the EMC list and ask any questions you need there. the CCED list I’ve mentioned is also a good place to ask questions.
Think in the CNC domain!
Alan KM6VV
I have EMC2 set up. I really like it so far. Also, if you don’t want to spend a bunch of money on CAD and gcode generation check into Google’s SketchUp with the Phlatboyz plugin for gcode creation. This video is long but gives an overview of SketchUp and shows the totally free plugin for generating gcode for your CNC machine that EMC2 can read.
phlatboyz.com/the-process-cr … ur-design/
I’m using this setup for enclosure cutouts, 2D. This setup is limited in 3D but improving. There are plugins for Eagle pcboard gcode generation too.
