Micro stepping stepper motor doubts

[raman00084]

how micro stepping stepper drive works?
i have a stepper motor with 1.8 degree that is if i give one pulse it must move 1.8 degrees for 200 pulses it must move 360 degree.

how this principle changes in micro stepping drive if i use the same 1.8 deg stepper motor in micro stepping drive i am getting upto 25000 pulses for one rotation that is if i give 25000 pulse it moves 360 degree that is one rotation.

my doubt is basically the motor is designed for 1.8 degree per step how this stepping angle gets reduced by using micro stepping drive

 

[D.A.(Tony)Stewart]

Microstep involves PWM so it dithers the applied voltage so it only moves according with PWM duty cycle. This gives fine tuning position at the expense of reduced maximum torque and constant applied PWM power.

A counter may keep track of microsteps and adjust PWM almost linear microposition interpolation between steps and resolution of counter. It can also be used for smooth stepping or acceleration, again at the expense of torque but can reduce overshoot.

 

[aandavan]

Hi SunnySkyGuy,
Can you explain with a sample code please

 

[amayilsamy]

Hi..

Given link is having A3967 micro step driver datasheet, refer the datasheet you can understand better about microstepping.

**broken link removed**

 

[doraemon]

Hello!

The principle of microstepping is not very complicated (but the implementation can be).
Imagine one magnet and 2 perpendicular coils A, B.
If you power one coil at a time, you will have 4 positions depending on whether you power A and B
in one direction (+) or the other (-).
So if you write that on a piece of paper, A+ will turn your magnet for example towards the axis X+ (let's call
that 0 degree) then B+ will turn your magnet towards Y+ (90 degree) and similarily for X- (180) and Y- (270).
The switching sequence will be: A+, B+, A-, B-
I suppose you understand until here.
Now what happens if you power with the same current A and B? Your magnet will be oriented at 45
degree. The switching sequence will be: A+, (A+&B+), B+, (B+&A-), A-, etc.. and you will have 8
"microsteps" of 45 degrees each although your motor was designed for 4 steps of 90 degrees.

The same principle applies to any stepper motor. I explained half steps with equal currents, but if you
can control current accurately, you can also make quarter steps (make one current 3 times stronger as
the others, and you will have quarter steps). Then you can calculate what you should power for even
smaller steps.

Dora.