PI Controller Design for MIMO process on the Autoclave Passivation

Passivation Autoclave is a device used to passivate (make passive) the surface of the nuclear fuel element beam cladding, so that the metal surface will have a low corrosion rate. This autoclave system is a heating furnace with a Multiple Input Multiple Output (MIMO) $3 \times 3$ model. System identification is performed experimentally directly on the device to derive a mathematical model in the form of a first-order transfer function. The inverted decoupling technique is used to reduce interactions in the MIMO model, followed by the implementation of PI control within this mathematical model. The control simulation results for the ramp function, with a temperature increase rate of $100^{\circ} \mathrm{C}$ per hour at a temperature setting of $200^{\circ} \mathrm{C}$, indicate a steady-state error of $7.8{ }^{\circ} \mathrm{C}$ for y
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and $36.5{ }^{\circ} \mathrm{C}$ for y
3
. Experiments for PI control testing were conducted directly using the ramp function, with a temperature increase rate of $100^{\circ} \mathrm{C}$ per hour at a temperature setting of $200^{\circ} \mathrm{C}$. The results of this experiment indicated that the steady-state error for each of the three outputs averaged 1.15%, with the largest error observed in output y
3
at $195.24^{\circ} \mathrm{C}$, or 2.38%. The steady-state error value, which is below 5%, meets the achievement criteria which shows the performance results of the control scheme