The invention provides a method for transforming a continuous-time filter to a discrete-time filter. The method includes: sampling input quantity and output quantity of a controlled
system, and utilizing an identification
algorithm for obtaining a continuous-
time model of the
system; constructing the continuous-time filter according to the continuous-
time model; adopting a
partial differential equation method to compute a
coefficient matrix of the discrete-time filter according to coefficients in a continuous-time filter equation and adopted time of a
discrete system; and constructing a discrete-time filter structure. The discrete-time filter is obtained by performing discrete transformation to the designed continuous-time filter. Compared with an existing discrete-time
filter design method, the method has the advantages that
discretization processes of a controlled object and filter designing processes based on the
discrete system are decreased, and by utilizing advantages of a
filter design theory based on a continuous-
time system, the filter excellent in performances can be designed,
system design and development time can be saved, and the method is particularly suitable for practical
engineering application of
digital control systems.