Design of model reference adaptive control systems based on virtual error method

Systems that are controlled as following to the ideal response hoped for it are called Model Reference Adaptive Control Systems (MRACS). The design method of MRACS for discrete-time systems under ideal condition has been already proposed, and a variety of application examples has been presented. These method require the accurate order of error transfer functions for the stability. This paper proposes a design of the adaptive control systems based on virtual error approach for the discrete-time plants. This method enables the proof of the stability without the accurate order of the error transfer function.