Control Law for Fast, Non-Ringing Transients for Dynamic Systems

"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."