La. Pineiro et Dj. Biezad, REAL-TIME PARAMETER-IDENTIFICATION APPLIED TO FLIGHT SIMULATION, IEEE transactions on aerospace and electronic systems, 29(2), 1993, pp. 290-301
In-flight simulations are normally accomplished using model-following
control laws which depend on accurate knowledge of the stability deriv
atives of the host aircraft. Degraded simulation results if the stabil
ity derivatives deviate considerably from their presumed values. Gain
scheduling is often employed to compensate for plant parameter variati
ons, but this form of open-loop compensation usually requires extensiv
e flight testing for proper fine tuning. An adaptive, fast-sampling co
ntrol law to compensate for changing aircraft parameters is described.
The step-response matrix required for implementation is identified re
cursively using a technique which does not need special ''test'' signa
ls and which automatically discounts old data depending on the input e
xcitation detected. Tracking fidelity is maintained despite parameter
changes which occur either abruptly or slowly, and actuator position a
nd rate limiting are discussed. The performance of the resulting syste
m is excellent and demonstrates the relative advantages of adaptive co
ntrollers for in-flight simulation.