zalzon said:
Hi,
couple o questions.
1)
Whats the different between stepper and servo motors? My
understanding was that stepper motors are used for motion while servo
motors are used for steering the front wheels.
The shortest answer is that they are completely different and have
nothing to do with each other, and shouldn't be confused.
A servo is more than a motor: it's both a motor and a feedback
mechanism. You tell a servo "I want you to move to the following
position" and the servo just plain does it. Commercial servoes
typically have a fixed range of motion; they can turn their output
shaft something like 270 degrees lock to lock. This makes them good
for things like steering; you just say "go to straight ahead" and
quit worrying about it.
A stepper motor is, in some respects, the exact opposite of a servo.
You tell a stepper motor you want it to move a step, and it does so.
Keeping track of how many steps it's gone, and details like not giving
it too many steps too quickly, are up to you. A stepper can keep
going round and round, which is why it's good for drive wheels.
Notice that you can do a servo in software by using a stepper, and
counting how many steps you've given it.
2)
How many kgs/pounds can two DC 4volt, 0.9amp motors move?
Could I move say 20 pounds with that on rc car wheels?
Nowhere near enough information. How much torque do the motors
provide? How are they geared? What sort of acceleration do you want?