Dexterous external space manipulation: serial or parallel concepts comparison

Within the external space manipulation framework, we compare two concepts to achieve an accurate positioning of the manipulator end effector. The first one involves a serial mini-manipulator inserted between the external space manipulator (macro-manipulator) and the end effector. Then, an anchorage mechanism is required to provide a hold point to the macro / mini manipulators interface. This solution can be called: static positioning of the minimanipulator \nbase. The anchorage system stiffness is then discussed. In the second concept,the mini-manipulator serial architecture is replaced by a light parallel architecture. The macro \nmanipulator is then used to provide a dynamic positioning to the mini-manipulator base by the mean of a coordinated control scheme between both manipulators.