Multi term power series fitting with MATLAB
1 view (last 30 days)
I would like to do parameter-identification of a DC motor.
The estimation is based on the attached pdf file.
I would like to fit mullti term power series (built-in function is only able to estimate with maximum 2 term) to the data, which also attached with time domain.
The equation is the following:
The motor parameters can be calculated from these constants as described in the pdf.
Do you have an idea how to calculate these constants?
Star Strider on 29 Jan 2020
D = load('NoLoadSpeed.mat');
T = load('Time.mat');
NLS = D.MotorSpeed_NoLoad; % Column Vector
t = T.Time; % Column Vector
pdv = 2:9; % Power & Denominator Vector
DM = t.^pdv./cumprod(pdv); % Design Matrix
BetaVct = DM \ NLS;
NLSfit = DM * BetaVct; % Fit Regression
plot(t, NLS, '.')
plot(t, NLSfit, '-r')
legend('Data', 'Fit', 'Location','E')
The ‘pdv’ vector can only go to 9 before the design matrix loses rank. This produces 8 β coefficients (the ‘BetaVec’ vector).