![]() |
Stepper motor questions
Hey guys. I am an alumni of FRC Team 514. I am not completely sure this is the correct location for this thread, if a moderator sees it fit, please go ahead and move it...
So, as part of a college project, we are working on developing a machine that is going to pump a very precise amount of fluid. Our basic design idea is one similar to that of a syringe pump. We are going to take a large syringe, and compress the plunger using a lead screw, which we plan on powering using a stepper motor we purchased. Now the problem is that none of us have ever used a stepper motor before, and we are having trouble coming by anyone, professor or otherwise, who knows enough about them to recommend what kind of control board we will be needing. The control of the system is going to be handled entirely within Labview, and we plan to do all of the controlling of the stepper motor using a National Instruments DAQ board (model 180955-01B). What I am basically trying to learn is whether or not we will be needing a separate control board, and what kind of board we will be needing that would be compatible with our daq board. None of us really have any experience in this, so some basic information to get us started and have a working stepper motor is all I really need. Here is a link to our motor: http://cgi.ebay.com/177-oz-inch-STEP...em19b954 4621 Thanks! -Rich |
Re: Stepper motor questions
I've built a couple CNC machines, and have had good luck with this one:
http://cgi.ebay.com/3-Axis-TB6560-CN...em3f033d 8ace It's really easy to use, and has a parallel interface for controlling with a computer. I've never used LabView before, but I'm assuming it allows you to interface with the parallel port. |
Re: Stepper motor questions
At work, I use peristaltic metering pumps to dose. what volume and and pressure are you looking at?
|
Re: Stepper motor questions
|
Re: Stepper motor questions
@Richard: This isn't an invention which we plan on applying for a patent with, just a solution to a problem which was assigned to us as a school project. Pumps like this have existed for much longer, such as the syringe pumps commonly used for the gradual injection of small amounts of fluid.
@gdeaver: We are looking to move anywhere between 1 and 1000 ml, with a precision of +-2 ml, We were going to use two 500 ml syringes, and so pressure will be very low. our stepper motor has a far higher torque than we need, we are using it because we got a deal on it. Basically all I need is what I can do to get this motor turning under control, and I can take it from there. |
Re: Stepper motor questions
Julio,
Your link indicates that the motor came with a motor driver board. The data sheet can be found here... http://www.sanyocomponentsdirect.com...K672-340-E.pdf With stepper motors, you need some feedback mechanism that can sense position and speed and a direction command. For your motor, it will also need a pretty hefty power supply. An FRC battery could supply the needed power or certainly a 12 volt pack of D cells would work as well. In your application, a motion limit might work but something that can sense the actual fluid flow would be better. Then you would just need to command a direction and enable the motor. Disable when the motor reaches the required distance/flow. |
Re: Stepper motor questions
Stepper motors are often operated open-loop with a relative position command (relative to the startup position or some stall position established at startup).
If the stepper motor torque capability substantially exceeds the maximum expected load, it is assumed that the motor will step faithfully when commanded, which eliminates the need for feedback. Of course, if safety is paramount then this type of open-loop control may not be appropriate (for example, if something were to jam and the motor was unable to move the load, the controller would not know). The control algorithm meters the steps at a rate slow enough that the motor will track faithfully (based on motor torque capability and expected maximum load). The algorithm keeps track of the commanded steps so it knows the position of the motor (relative to the startup position previously mentioned), without the need for a feedback sensor. |
Re: Stepper motor questions
Ether,
The stated use requires some form of feedback. The user intends to control a flow of 1-1000ml +/- 2 ml. |
Re: Stepper motor questions
Quote:
BTW, the Hurst step motor controller still works very well. |
Re: Stepper motor questions
Quote:
|
Re: Stepper motor questions
Quote:
Rich, you might consider Gdeaver's response more carefully, as a peristaltic pump can do that easily with at least an order of magnitude greater precision. |
Re: Stepper motor questions
Don,
As there are a number of variables here, atmospheric pressure being one, that influences flow rate, isn't some feedback needed? |
Re: Stepper motor questions
Quote:
|
Re: Stepper motor questions
But the syringe is...
|
Re: Stepper motor questions
Quote:
|
| All times are GMT -5. The time now is 15:09. |
Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
Copyright © Chief Delphi