Stepper motor controller

[aratti]

The profile algorithm transforms the travel command (steps) into three vector quantities:

Vector A Acceleration from rest to fixed speed
Vector B travel at fixed speed from end of vector A to begining of vector C
Vector C Deceleration from fixed speed to rest at target point

This technique is known as "TRAPEZOIDAL PROFILE".

When the travel command is equal or less than vector A + vector B
the algorithm convert the trapezoidal profile into "TRIANGULAR PROFILE"
calculating new vectors A & B with different slopes.(1/2 total travel)

For small travel command (few steps) the algorithm was yielding very sharp slopes stalling the motor. The bug has been found and removed!

Now the motor turns smootly also with few steps travel command at high speed.

The new version software (Stepper_Driver_2) is attached, as a zipped file, to this post.

Please note that the attached schematic (very simple to build) will tremendously improve
small motors performace (max 1.2 A current)

Al.

[DarthV]

Hello to all, i´m new here and i would like to start by saying thanks to aratti for posting this nice project.
I´m thinking about use it but i wish to drive stepper motors with an model RC receiver(PWM-8 ch frame) using 2 of the 8 channels, 1 for each motor, my question is,...is it possible to add some more routines into the code in order to implement these movements and thus replace 2 of the servo motors that i have ?

thanks in advance

G.V

[aratti]

Thank you DarthV, unfortunatly the 16F84A is full as an egg and you cannot add even one extra byte. The controller accept TTL serial commands so if your radio device has serial communication capabilities you can feed the commands into the controller using this way.
I am working on MK2 version and I a using a more powerfull pic device, which could have some space available at the end (But who knows, I will tell you only at the end). Post some more details on what you want to do, perhaps I could see how to solve the problem.

Al.

[tenaja]

Would you mind sharing the PBP code for the hex file you've already shared?

[aratti]

Why not! I need to comment it before. Give me few days.

Al.

[DarthV]

Hi, guys....well let me describe better what the needs are, i have 2 PWM servo outputs, each one is driving each servo from left to right,..., with a 5V TTL logic level, movement from left to right is changing the pulse width from 1ms to 2ms, with 1.5ms at center position,....the movement is like 0....to...60 degrees minimum angle, or a maximum 90 degress !

Thanks

[aratti]

DarthV, I have read your introduction to the problem. but you didn't write what your problem is.

Al.