Given a high order stable transfer function G, this code would compute the reduced order equivalent model for the system using Routh Approximation (or Gamma-Delta Approximation) of required degree.
Refer : V. Krishnamurthy and V. Sheshadri, " A simple and direct method for reducing order of systems using routh approximations in frequency domain", IEEE Transactions on Automatic Control, Vol. 21, pp. 797-799, Oct. 1976.
Computes the r-th order Routh Approximation of a given n-th order
transfer function G, with 1<=r<=n.
G=tf([1 2],[1 3 4 5])
gives the output as
0.5714 s + 1.143
s^2 + 2.286 s + 2.857
Updated program to include case of first order reduced model
Download apps, toolboxes, and other File Exchange content using Add-On Explorer in MATLAB.