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buntonj / polynomial_observers

Polynomial observers: a Savitzky-Golay filter for estimating the derivatives of an output signal, then using it to estimate the state of a nonlinear dynamical system.
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Fit and differentiate centered polynomials rather than endpoint differentiation #14

Closed buntonj closed 1 year ago

buntonj commented 1 year ago

For numerical stability, fit and differentiate the polynomials with centered values. Fitting might already be implemented by numpy's polynomial class (check).

When using this for control, we will need to evolve the state estimate forward in time to accommodate the delay caused by this approach.

buntonj commented 1 year ago

Need to update this for bound purposes also. Pushing to higher priority--need to clean up the notation/code for degree of polynomial, residuals, etc.

buntonj commented 1 year ago

Doing this adds estimation lag, which may be undesirable. Would have to evolve the dynamics forward in time after getting the estimate.