Parameter identification and intersample output estimation of a class of dual-rate systems

For a class of dual-rate systems in which the input updating rate is an integer multiple of the output sampling rate, a frequency-domain model with a finite number of parameters is derived; based on this model, new algorithms for parameter identification and intersample output estimation using directly the dual-rate input-output data are proposed. We study convergence properties of the algorithms in detail in the stochastic framework and show: 1) the parameter estimation error consistently converges to zero under the persistent excitation condition; 2) the intersample output estimation error is uniformly bounded; and 3) the estimated output at the sampling instants based on the past input-output data has the property of minimum variance. Finally, we illustrate and test the proposed algorithms with an example system.