# Enhancing Antifragile Performance of Manufacturing Systems through Predictive Maintenance
## 6 Method for Injection of Artificial Errors in a Virtual Environment
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{
\begin{tabular}{c} **Critical** \\ **Component** \\ \end{tabular} } & \multirow{2}{*}{**Failure Mode**} & \multirow{2}{*}{**Failure Cause**} & \multirow{2}{*}{**Failure Effects**} & \multicolumn{4}{c}{**Initial Risk Ranking**} \\ \cline{4-9}  & & & & **(S)** & & **Occurrence** & **Detectability** & **Risk Priority** \\  & & & & **(S)** & & **(O)** & **(D)** & **Number** \\ \hline
1. Programmable & & & & & & & & \\ logical controller & & & & & & & & \\  (PLC) & & & & & & & & \\ \hline
2. Programmable & & & & & & & & \\ logical controller & & & & & & & \\  (PLC) & & & & & & & \\ \hline
3. Programmable & & & & & & & & \\ logical controller & & & & & & & \\  (PLC) & & & & & & & \\ \hline
4. TP1500 Comfort & & & & & & & & \\ HMI trainer & & & & & & & \\ \hline
5. Conveyor belt & & & & & & & \\ with asynchronous & & & & & & & \\ AC motor & & & & & & & \\ \hline
6. Conveyor belt & & & & & & & \\ with asynchronous & & & & & & & \\  & & & & & & & \\  & & & & & & & \\  & & & & & & & \\  & & & & & & & \\ \hline
7. Conveyor belt & & & & & & & & \\ with asynchronous & & & & & & & \\ AC motor and IO & & & & & & & \\ \hline
8. SINAMICS & & & & & & & \\ G120—1 AC 230 V & & & & & & & \\ \hline
9. SINAMICS & & & & & & & \\ G120—1 AC 230 V & & & & & & & \\  & & & & & & & \\ \hline
10. Compact & & & & & & & \\ pneumatic & & & & & & \\ pallet storage unit & & & & & & \\  & & & & & & \\ \hline
11. & & & & & & & \\ RFID–SIGNENS & & & & & & & \\ RF300 & & & & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 1: FMEA analysis of station components (an extract), considering minimum occurrence risk. would affect all frequency convertors and conveyor belt motors but with a lower risk index. This risk index is computed based on the offline values for the occurrence factor, as identified in the FMEA analysis. For example, for the conveyor belt, the occurrence factor for motor failure under the event of motor failure will be set to 4, so the new risk index will become 128. The index factor for FREQ2 is computed also considering the initial occurrence factor of 5, thus resulting in a risk index of 240. By determining the new risk indexes (higher than previous in the case of component #3, #4, #5, and #6), we consider the learning phase produces visible results. In addition, by determining the different factors for the new indexes, the system reacts differently to different stressors and provides data for the decision-making process. Although research to validate antifragile design control solutions is in its infancy, the facilities offered by the DT-based CIDSACTEH testbed are promising and encouraging. To date, the performance of adaptive control procedures and physical controls has been assessed using HIL (hardware in the loop) and SIL (software in the loop) techniques--see details in [25]. Now, the research aims to increase this performance by addressing antifragile responses to the effect of uncertainties due to changes in the environment. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Critical Component** & **Identification** & **Initial Risk Index** & **New Risk Index** \\ \hline \(1\). Programmable logical controller (PLC) & PLC & 63 & 63 \\ \hline \(2\). TP1500 Comfort HMI trainer & HMI & 16 & 16 \\ \hline \(3\). Conveyor belt with asynchronous AC motor (Station 1) & B1 & 32 & 128 \\ \hline \(4\). Conveyor belt with asynchronous AC motor (Station 2) & B2 & 32 & 128 \\ \hline \(5\). SINAMICS G120—1 AC 230 V (Station 1) & FREQ1 & 48 & 480 \\ \hline \(6\). SINAMICS G120—1 AC 230 V (Station 2) & FREQ2 & 48 & 240 \\ \hline \(7\). Compact pneumatic pallet storage unit (Station 1) & SO1 & 12 & 12 \\ \hline \(8\). RFID—SIGENS RF300 (Station 1) & RFID1 & 36 & 36 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Risk index of station components (an extract), considering artificial failure injection. Figure 4: Method for artificial failure injection and analysis.