Fig。 6。 Identification process for unknown cable dynamics。
Fig。 8。 Frequency responses of the disturbance model (cable model)。
Fig。 9。 Feedback system representation。
Fig。 10。 Feedback system representation based on robust control ap- proach。
Fig。 7。 Responses of disturbance model (cable model)。
as the following transfer function:
any loss of generality, and a generalized plant with controller based on the Hmethod is illustrated in Fig。 11。 Therefore, the control system design objective is equalized to obtain a
controller K (s) which satisfies the norm condition:
7。68 10s 3。79 103
Gd (s) 3 2 3 4 。
s 27。78s 1。64 10 s 1。43 10
4。 Controller design and experiment
is the transfer function from w to
z zT zT , and W (s) is a weighting function to shape the
Based on the proposed idea and identification results, we
design a robust control system。
For example, if we introduce the Hcontrol theory [11, 12], a feedback system configuration is obtained as shown in Fig。 9 where the cable dynamics Gd (s) is considered as disturbance
and uncertainty (s), because the cable motions produce force
output sensitivity function。
Let us describe the transfer functions and W (s) in Fig。 11 as follows:论文网
variations for the winch system as described in the previous
section。 Then, Fig。 9 is directly depicted as Fig。 10 without
Then, the feedback system with the controller K (s) is stable if and only if there exist the positive definite matri- ces X and Y which satisfy the following conditions [11, 12]:
and the elementary matrices in Eq。 (11) are defined as follows:Using MatLab Tool, the controller satisfying the given con-
Then, a controller stabilizing the closed-loop system and and the weighting function W (s) is selected as follows:
satisfying the constraint
Based on these results, we present the simulation results。 First, Fig。 13 shows the disturbance rejection performance
Fig。 12。 Step type disturbance input to the vessel : simulation。
Fig。 13。 Disturbance rejection performance with designed controller : simulation。
Fig。 14。 Control input made by controller : simulation。
Fig。 15。 Sinusoidal type disturbance (frequency range: 1 to 15 Hz, amplitude: 1 N) : simulation。
of the proposed control system where a step type disturbance shown in Fig。 12 exists and the distance target of the con- trolled vessel is 0。05 m。
Fig。 14 depicts the control signal produced from the control- ler to cope with the disturbance input。
Fig。 16 shows the control performance when the vessel is exposed to the sinusoidal disturbance input as shown in Fig。 15, and Fig。 17 is the control signal made by the controller。
As shown in the simulation results, it is clear that the de- signed control system with proposed control strategy works well。 船舶系泊绞车系统英语文献和中文翻译(4):http://www.youerw.com/fanyi/lunwen_203348.html