Singularly Perturbation Method Applied To Multivariable PID Controller Design

Table 5

Characteristic of closed loop response for evaporator system.

Output	Method	Rise time, (s)		Settling time, (s)		Percentage overshoot (%OS)		Steady state error, (%)
		Step		Step		Step		Step
		Up	Down	Up	Down	Up	Down	Up	Down
Separator level,	Davison	34.5	43.3	—	117	11.67	8.02	0.2	—
	Penttinen-Koivo	1.1	1.2	5.9	2.19	5.20	0.23	0.03	0.01
	Combined	0.9	1.6	5.4	7.5	3.67	—	0.01	0
	Fauzi	8.1	0.8			7.40	3.71
Operating pressure,	Davison	30.3	34.4	—	139.6	10	10	—	0.5
	Penttinen-Koivo	0.7	1.3	1	1.8	—	—	1.45	0.15
	Combined	1	1.9	2	3.1	—	—	0.05	0.05
	Fauzi	2.5	2.4			15

Unstable.