Conception, modélisation et optimisation des actionneurs polyentrefers à bobinages globaux : Application aux structures linéaires multi-tiges

The aim of this thesis is the study and the conception of splited structures of global coil synchronous machines for the maximisation of specific torque or thrust. This concept of machine, called multi-airgap, is more precisely applied to the elaboration of a new linear multi-rods actuator. It is clearly connected to the context of direct drive solutions. First, a classification of different electromagnetic actuator families gives the particular place of multi-airgaps actuators. Then, a study, based on geometrical parameters optimisations, underlines the interest of that kind of topology for reaching very high specific forces and mechanical dynamics. A similitude law, governing those actuators, is then extracted. A study of mechanical behaviour, taking into account mechanic (tolerance) and normal forces (guidance), is carried out. Hence, methods for filtering the ripple force, and decreasing the parasitic forces without affecting the usefull force are presented. This approach drives to the multi-rods structures. A prototype is then tested and validates the feasibility of that kind of devices, and the accuracy of the magnetic models. This motor, having only eight rods for an active volume of one litre, reaches an electromagnetic force of 1000 N in static conditions. A method for estimate optimal performances of multi-rods actuators under several mechanical stresses is presented.