Fault Monitoring Based on the VLSW-MADF Test and DLPPCA for Multimodal Processes

. 2023 Jan 14;23(2):987. doi: 10.3390/s23020987

Algorithm 2. Online monitoring phase.

Step 1: Input online process data

X_{o n l i n e}

;

Step 2: Determine the mode of the starting phase by minimum

SPE

;

Step 3: Monitor the current continuous

ω

data from

(k - ω + 1)

k

using an offline model corresponding to

(k - ω)

time data;
Situation 1: Below the control limit.
The current process mode is the same as the previous one.
Situation 2: Exceeding the control limit.
Situation 2.1: The current process has a fault situation.
Situation 2.2: The current process enters a new mode.
Situation 2.2.1: The process is in transition mode at the previous moment.
Situation 2.2.2: The process is in stable mode at the previous moment.

Step 4: For situation 2.2.2, calculate matching value

m_{i}

for online modal recognition.

Step 5: Use the model determined in step 4 to remonitor. If it is below the control limits, the currently selected model matches the actual mode. If it exceeds the control limits, a fault has occurred.