This paper discloses the simultaneous and interdependent development of an
actuator and its novel control law. Magnetostrictive alloy terfenol-d offers
high energy density. When packaged properly, quantum mechanics within terfenol-d
maintains its performance. The novel control law tames and directs its untapped
potential. Therefore, terfenol-d can provide lifetime direct operation of the
needle in an injector for a compression-ignition engine, potentially improving
emissions, efficiency, fuel flexibility, and combustion noise.
The novel control law yields a custom forcing function for desired boundary
conditions such as either non-ringing or deliberately ringing transients for
this actuator as well as other non-magnetostrictive dynamic systems. The two key
characteristics that enable such a custom forcing function are to (1) use the
Bright Principle of modeling all energy terms and (2) setting up a specific
polynomial to solve for the desired boundary conditions for a particular dynamic
system.
Test data from an actuator aided the development of this general and flexible
control law. Implementing the control law, a computer predicts the necessary
voltage with respect to time to achieve a set displacement within a defined
transient time. A difference in frequency content appears between fast Fourier
transform (FFT) spectra of non-ringing followed by deliberately ringing
displacement data.