Temperature control algorithm for polymerase chain reaction (PCR) instrumentation based upon improved hybrid fuzzy proportional integral derivative (PID) control

Here is reported an adaptive polymerase chain reaction (PCR) temperature control algorithm based on improved hybrid fuzzy proportional integral derivative (PID) control. The algorithm adopts fuzzy control in the rapid temperature changing stage for monitoring and reduces the overshoot. In the constant temperature stage, the PID controller's initial parameters are automatically calculated online through the relay self-tuning algorithm. The output of the system is pre-compensated by feedforward compensation algorithm, and adjusted by the variable universe fuzzy PID algorithm, which avoids the explosion of fuzzy rules to a certain extent. The experimental results show that the average heating rate of the improved hybrid fuzzy PID control algorithm is 4.2 degrees C/s, with an average cooling rate is 3.2 degrees C/s. The system stabilizes within 5 s with a maximum overshoot of less than 1.2 degrees C and a static error of +/- 0.1 degrees C at various ambient temperatures.