Multicriteria design of an electromagnetic hammer

In this paper, a Pareto based multicriteria design procedure for a linear motor driving an electromagnetic demolition hammer is presented. The hammer application requires high dynamical performance as it must deliver at the same time high value of impact energy and frequency of cycle. The uncertain characteristic of the medium on which the hammer head will impact has to be taken into account in an integrated electromechanical model of the system that could guide the control strategy of the supply system. Requirements of the application are stated and some preliminary analysis that lead to the choice of a Linear Permanent Magnet Synchronous Motor are described. The integrated electromechanical model, taking into account the modelling of the head impact on the soil is described. Some of the principal results show that the solution is not unique but comes out of a spread of possibilities so that Pareto criterion is used to sort them out. Simulation results obtained on the main operative hammer quantities are presented and discussed.