Ball and Beam Conrtol Help

[sakura15]

I am making a ball on beam project. I just wanted to know how to make a unstable transfer function function. the ball on beam model is 0.21/s^2 and i want to make it stable so that i can control it using pid. please help me out in this problem . Im writing the code in labview Rt.

[altenbach]

Is this an algorithm question or a programming question?

Is this a real ball/beam or a simulation?

[sakura15]

real ball on beam not simulation. I want the solution for both algorithm and programming.

[Lysandros]

the ball on the beam model, has a squared "s" in the denominator, which means it has two poles at zero. If you want to create an unstable model, you can achieve this by a positive pole in the denominator. This can be interpeted in that a constant force or perturbation will lead to an ever increasing output.

Example:

1/(s-1)    Pole is: s=+1  Positive therefore unstable pole.

1/(s^2)    Pole is: s=0,0  Zero, similar to rigid body motionm which is nowhere attached

1/(s+1)   Pole is: s=-1   Negative therefore unstable pole.

With your controller you essentialy bring the poles of the entire system (loop of plant & controller) in the negative regime. A good tool to test such loops is in Simulink, but in Labview, using a while loop is also an option.