Trial & Error Method of PID Tuning.

TRIAL AND ERROR METHOD OF PID TUNING

The Trial and Error method requires a closed loop system, it steps through the system from proportional to integral to derivative.

This method is a divide and conquer approach, first it puts the system into a rough solution from which small tweaks are performed to perfect the response.

1. To begin, each coefficient of the PID controller is set to zero.
2. The proportional component is now considered by increasing its value until a steady oscillation is obtained . Scaling the current proportional value down by a factor of two will give the resulting proportional value. Applying this proportional value will dismiss the steady oscillations.
3. Next the integral coefficient is increased until steady oscillations are again obtained. The present value of the integral coefficient is scaled up by a factor of three and applied to the integral as the final value. This once again sets oscillations off, which brings up the derivative control, this value is increased until for a final time the oscillations are at a constant period and amplitude.
4. The coefficient of the derivative is then scaled down by a factor of three and applied as the final value for the derivative control. The resulting output may still have some noise associated with it, this must now be tuned by hand with small educated tweak of the different coefficients.