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Underwater Robots - Gianluca Antonelli.pdf

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7.8 Output Feedback Control 177<br />

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Fig. 7.15. Output feedback control; first case study. Comparison between the<br />

control laws (7.41),(7.42) and (7.62): vehicle control moments. Left: control<br />

law (7.41),(7.42); Right: control law (7.62)<br />

the measurements relative tothe subsystem with faster dynamics (i.e., the<br />

manipulator) remains the same (100Hz), while the update rate of the measurements<br />

relative tothe vehicle (5 Hz) isstill adequate to its slower dynamics.<br />

Figures 7.19 to7.21 show the corresponding control forces, moments and<br />

torques. It can be recognized that unacceptable chattering onthe control<br />

inputs is experienced when numerical derivatives are used, which isalmost<br />

completely cancelled when the controller-observer scheme is adopted.

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