Larry's Blog

A NEW ROBOT

This new robot is pictured on the right. It is called
STEPBOT and is powered by stepper motors.

I am coming to grips with problems of torque. The wave pattern
is the easiest to drive a stepper. These are unipolar stepper
motors. So I went to a half-step pattern which should give me
more torque - I hope. There is still another pattern that I can look into.
With the DC motors there seems to be no problem with torque.

Stepper motors for locomotion do have some advantages.
To reverse direction, I just send the patterns in the opposite
sequence. To stop, I just stop sending the signals.

An example of wave pattern is as follows:
1 0 0 0
0 1 0 0
0 0 1 0
0 0 0 1

Each of the one's represents energizing one of the coils
in the stepper motor. You just repeat sending this pattern over and over
and the motor steps ahead. The pattern for the half-step
is more complicated, but basically energizes 2 coils
on some of the patterns.

Of course, I am sending these patterns to 2 stepper motors,
so I can make one stop or go in reverse while the other
goes forward.