Interaction transfer function matrix and the design of multivariable control systems

The ITF (interaction transfer function) technique has been developed to reduce the multivariable design problem to a sequence of scalar problems. The ITF can be easily calculated and used to determine the stability of the multivariable systems by using a computer-aided design technique. The stability can be determined from Nyquist loci of some diagonal ITFs. The compensation of multivariable systems can be achieved by compensating the diagonal ITFs of an ITF matrix directly. Two examples are used to demonstrate the use of the design technique