Society of Robots - Robot Forum
Electronics => Electronics => Topic started by: dmehling on August 26, 2007, 03:56:02 PM
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I have just about decided to use a basic stamp for my robot, and now I am trying to determine what kind of motor driver I need for my stepper motors. I will be using two of these motors; one to raise and lower a platform weighing 15 to 20 pounds and the other motor to slide that same platform forwards and backwards. Both of these motors will be using a screw thread drive to accomplish this linear movement. I am not sure how powerful of a stepper motor I need as well as the type of driver/controller I need.
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There are a couple of unknowns in the equation for torque needed for your application. Screw pitch and efficiency.
But anyway, for example-
screw pitch = 2mm = 2x10-3m
efficiency = 70%
mass of platform = 10kg (i like metric :))
work in x efficiency = work out
torque x 2pi x efficiency = mass of platform x acceleration due to gravity x screw pitch
torque x 2pi x 0.7= 10 x 9.8 x 2x10-3
torque = (98 x 10-3) / (pi x 0.7) = 0.044unipolar and bip6Nm = 4.46Ncm
The driver you want to choose depends on 2 things - unipolar or bipolar motor? and how much are you willing to pay?
unipolar motors have 5,6 or 8 leads and require a different driver to a bipolar which have 4 leads.
If you wanna keep costs down, then you can build your own driver - http://aaroncake.net/circuits/stepper.asp (http://aaroncake.net/circuits/stepper.asp)
otherwise there are plenty of commercial drivers out there to suit your needs.
Harry