Singularly Perturbation Method Applied To Multivariable PID Controller Design

Table 2

Characteristic of closed loop response for WWTP.

Output	Method	Rise time, (h)	Settling time, (h)	Percentage overshoot (%OS)	Steady state error (%)
Substrate,	Davison	2.0	44	45.65	0.152
	Penttinen-Koivo	1.8	21	8.65	0.092
	Maciejowski	0.9	14	5.65	0.032
	Combined	0.1	11	0	0.012
Dissolved oxygen, DO	Davison	1.0	14	62.49	0.03
	Penttinen-Koivo	1.2	5.5	21.58	0.03
	Maciejowski	0.1	0.2	0	0.17
	Combined	0.1	0.4	0	0.02