DYNAMIC ANALYSIS OF A MANIPULATOR IN A FLUID ENVIRONMENT

The computation of the generalized forces produced by a fluid acting o n the links of manipulators is considered here. The evaluation of thes e forces is necessary for the controller of an underwater manipulator (partially or totally immersed). This article presents an approximate method for the computation of buoyancy in local coordinates. The drag forces are computed by numerical integration of the local drag force. Numerical integration is necessary here to achieve a good precision. A new local reference frame is also added on each link to allow an easy description of the geometry of the links. When those computations are included in the dynamic model, a compromise must be made between comp utation time and precision, because this inclusion may result in doubl ing or tripling the number of operations to be performed in comparison with a standard dynamic algorithm.