I built a new style PID trainer, trying to make it more affordable then our current model, this one seams simple but I can get it... before I build them I need to make sure they function correctly and they will work mechanically.
Your first problem is that this is not an easy system to control, duh.
Simple ball on a piece of angle with a motor for the up and down on one end but regardless on the PID setup I cant get it, I have changed every setting that I know and I thought I was decent at setting them up
The second problem is that it is not an easy system to control. it can be controlled with a PID but it is not easy because is not linear.
Is it possible that there is such a thing as not able to set a PID? maybe my motor is to slow/fast?
I doubt it is a motor problem
This is not an easy system to control.
Get the hint?
I was going to have a fan oscillate to give another dimension but I cant get this one let alone introducing more variables
Now you want to make a system that is not easy to control even harder. Good luck.
Find something easier to control like Ron Beaufort's hot rod temperature control systems he used for training. This was discussed back in 2005.
We have a system like that some where around Delta Motion.
I think it morphed into a 6DOF system were we rolled ball through a maze for a trade show.
Originally the simpler system back and forth balancing system was used for a project by the local university for a senior project. They flailed and failed for a few weeks. They were clueless as to why they couldn't get it to work ( our new university system ). They didn't try to model the system. They were trying to use trial and error. One time I just happened to be walking by ( I am retired and not normally at the office ) and I saw what they were attempting to do. I told them they were doing it all wrong.
The system they built was similar to GITs, and were trying to balance a 1 inch steel ball. That was a mistake. Too much mass, too much energy. I told them to replace the steel ball with a ping pong ball. That helped a lot. The trick is how do you remove the energy?
I modeled the system using Mathcad. I got it done but they were able to get the TT ball to balance by moving the ball slowly.
drbitboy said:
Have you modeled the system?
Modeling the system helps in understanding the system. The problem is that one must keep track of the energy that the ball has. One is starts moving it has a lot of kinetic energy, both translational and rotational. The kinetic energy must be reduced to 0 to stop the ball and this can't be done if the ball is rolling too fast. If the ball is rolling too fast you can't stop it by tilting the system enough before the ball rolls off the edge. Energy is added by tilting. Then the ball has potential energy and will start to roll down hill trading off potential energy for kinetic energy. If the ball gets too close to the pivot before it is slowed down, it is too late. The angle of the tilt requires a trig function.
I worked out the math for the students but it was over their heads. Only one student even knew about solving non-linear differential equations using Runge-Kutta. The system isn't linear and it requires some trig in the transfer function.
This is a good example of why real control experts use systems of differential equations.
I can show you the math but I don't know what good it will do. Your tilt system is too complicated for beginners. Did I mention this is not an easy system to control?