Underwater Robots - Gianluca Antonelli.pdf

7.2 Feedforward Decoupling Control
7.2 Feedforward Decoupling Control 143
In 1996 T. McLain, S.Rock and S. Lee, in [205, 206], present acontrol
law for UVMSs with some interesting experimental results conducted at the
Monterey Bay Aquarium Research Institute (MBARI). A1-link manipulator
is mounted on the vehicle OTTER (see Figure 7.1) controlled in all the 6-
DOFs by mean of 8thrusters. Acoordinated control is then implemented to
improve the tracking error of the end effector.
Fig. 7.1. OTTER vehicle developed in the Aerospace Robotics Laboratory at
Stanford University (courtesy of T. McLain, Brigham Young University)
In order to explain the control implemented let rewrite the equations of
motion for the sole vehicle in matrix form as
M v ˙ν + C v ( ν ) ν + D RB( ν ) ν + g RB( R I B )=τ v − τ m ( R I B , q , ζ , ˙ ζ )(7.1)
where τ m ( R I B , q , ζ , ˙ ζ ) ∈ IR 6 represents the coupling effect caused bythe presence
of the manipulator. The control ofthe vehicle and ofthe arm isachieved,
independently, by classical control technique. The coordination action