Presented below is a summary of the results obtained to date on the verification of a novel state space model identification technique called PLID (Pseudo Linear IDentification), given in Hopkins et al.1 This technique has several unique features that include: (1) optimal joint parameter and state estimation (that gives rise to its nonlinearities); (2) provisions for sensor, actuator, and state noise; (3) and it converges almost surely to the true plant parameters provided that the plant is linear, completely controllable/observable, strictly proper, time invariant, and all noise sources are zero mean white gaussian (ZMWG). Experiments carried out on a flexible, modally dense 3-D truss structure standing 4 feet tall have shown PLID to be a robust technique capable of managing significant deviations from the assumptions made to prove strict optimality. Using the 3 actuators and 3 sensors attached to the structure, models varying in size from 24 to 64 states have been used to approximate this infinite dimensional testbed in the frequency range between 50 to 500 Hz. Sensor signals with RMS levels of approximately 2 volts have been predicted by PLID to within 0.01 volts RMS.
Date of creation, presentation, or exhibit
Department, Program, or Center
Microelectronic Engineering (KGCOE)
Vallone, Phillip and Hopkins, Mark, "Experimental verification of a novel system ID technique called PLID using a flexible 3-D structure" (1995). Accessed from
RIT – Main Campus