Simultaneous PID self-tuning and control

Controllers are usually needed to tune before they work. This often results to offline model identification and/or a long tuning time. We present a model-free tuning method for proportional-integral-derivative (PID) controller. Using this tuning method, PID controller is tuned while it functions simultaneously. To achieve this goal, a desired controlled model with respect to the PID parameters is introduced. The PID parameters are tuned continuously when the desired model approaches to the unknown actual model. The system controlled by the resulting PID has satisfactory performance. The proposed scheme can also be used to design an adaptive PID.