Hi !

I like to plan to do this again with a stepper motor.


The project will be relatively the same as on the video. A laser sensor to know the distance of the ball and a stepper motor without encoder to manage the inclination of my pendulum.

I was wondering how to do my regulation in such a way that it controls my engine. For regulation and motion control I know how to configure my technological objects but it's really the connection between the two that I call.

THANKS 

Hi maxmax, interesting problem, following the link in the video description I see that a SERVO has been used. A servo is different from a stepper.

In a servo you control the absolute angle, in a stepper without encoder you just control relative rotation.

Trying to do this, with decent repeatability, without at least a "homing" limit switch is basically impossible.

If you have a homing position you can then do some pretty basic extrapolation of PID output => number of steps/direction   and you end up with a homemade servo.

A fun addition could be monitoring the expected acceleration of the ball compared to PID output to check if there are missing steps and correct accordingly (or you could just check against the homing position each time you cross it, but I've been known for my tendency to overcomplicate simple stuff).

In my experience I have worked with regulators and actuators without feedback, and if there is something I have learned is not to do it again. Even if it is possible to account for added tolerance by controlling an indirect effect, once the regulator compensates for some type of offset things can go bad because you loose track of where things are.

Having said that, if you really want to use a stepper maybe another way could be monitoring the angle of the bar and having 2 regulators.

Hi,

thank you for your answer! What poses a problem for me is the control of my S210. I know how to make it move but each time with positrons, for example, rotate it by X mm. My movement is activated with a rising edge. So it's complicated because he doesn't know how to read a position and go straight there. Basically, I can't use a 0-10V potentiometer, for example, to move directly over 100mm, for example. And I can't find no way to do this

In short how to synchronize the value of my analog input to the position of my servo a bit like in this video but suddenly one of the axes is a potentiometer