Need help with stepper motor profile with Accelstepper.h

Other Hardware Motors, Mechanics, Power and CNC
1

Hi guys,

This is my first time posting here. I currently have a project where we need to make a profile for a stepper motor with accel, constant speed, decel, and a delay.

After some research, i found that the accelstepper library has the acceleration and deceleration function.

Below is the profile that i am required to make.

Below is the code i used

#include <AccelStepper.h>

// Define a stepper and the pins it will use
AccelStepper stepper(AccelStepper::FULL4WIRE, 8, 9, 10, 11);
//no of step to move to achieve 40step aka 20ms

void setup()
{  
  //setup accel speed 20steps/sec,accel: 5steps/sec. Accel/decel should be 4s (20/5)
  stepper.setMaxSpeed(20); 
  stepper.setAcceleration(5);
}



void loop()
{
  if (stepper.distanceToGo() == 0)
  {
    //delay 3s here for the idle
       delay(3000);  
// set the distance to move 120steps = 80steps for accel+decel, 40steps constant speed. 40steps = 2 secs.
       stepper.move(120);
  }
          stepper.run();

 }

The distance is calculated with D=V*V/2A *V= max speed, A=Acceleration.

From the code, one cycle should be around 10second (exclude idle). When i try to use a stop watch, it is around 9+ seconds.

i am using LED to check the timing of the profile now

I would like to know if i am coding it correctly? or the stop watch was not timed properly?

2

The AccelStepper library bases its acceleration profile on the number of steps and the acceleration rate, not on time. And it is designed to accelerate from 0 to the max speed and then decelerate back to 0 within the number of steps in a single movement.

You may be able to figure out a number of steps and an acceleration rate that has the by-product of producing the profile you require.

Alternatively it is not difficult to write your own acceleration code. The code in this link should give you a starting point.

...R

3

Hi Robin,

Thanks for the reply.

I have tried to understand your code in the other thread. It seems to be a little too advance for my level. I am quite new to this actually.

From your code, seems like there is only 2 pins used. 1 for direction and 1 for steps only.

Can you provide some simple guide for me?

4

lcs1987:
Can you provide some simple guide for me?

Sorry. Just realized I forgot to attach these links to my earlier Reply.

Stepper Motor Basics
Simple Stepper Code

...R