  Electromechanical relays and contactors suffer from strong collisions at the
end of the switching operations. This causes several undesirable phenomena,
such as clicking, mechanical wear and contact bounce. Thus, there is great
interest in mitigating these switching impacts while keeping the advantageous
features of these devices. This paper proposes a complete control strategy for
soft landing. The control structure includes three main components. The first
one is a real-time flux-tracking feedback controller, which presents several
advantages over voltage or current control. The second one is a feedforward
controller, which computes the flux reference signal based on a proposed
dynamical model and the desired position trajectory for the switching
operations. Lastly, the third control component is a learning-type run-to-run
adaptation law that iteratively adapts the model parameters based on an audio
signal. It exploits the repetitive nature of these devices in order to
circumvent modeling discrepancies due to unit-to-unit variability or small
changes between operations. The effectiveness of the proposed control is
demonstrated through various experiments.
