I am using a PID Neural Network (PIDNN) algorithm to control a multi-zoned temperature hardware. The aim of the algorithm is to minimize the error with the Backpropagation rule and weights updating.
The device is commanded by B&R X20CP1484 CPU.
Unfortunately, the device has a very large inertia (SetTemperature 60°, ActualTemperature can reach 72°). Stabilizing the system requires a very long time, but always with few degrees above and below. PS: This is the case when controlling only one zone (the model has 4 zones, let alone controlling the 4 zones).
I thought about decoupling, and added all necessary equations. Still, the system has a very large inertia, heating is unstoppable. I am using a PWM too, so when the sensor value is equal to set value, duty is 0. Then temperature keeps rising even when the heater is off.
The question is: Are the PID parameters wrong? Is there a problem with the PWM period?
The same model was controlled before with GPC and had perfect results.
Device is using 4 SSR, the 4 sensors are few CMs close to the thermocouple.
Any suggestions? Thanks in advance.