Section 9.1 The 2DOF Structure for Stable Plants C1(s):The design of Cl(s)is the same as that for the controller in a 1DOF system C2(s):After C1(s)is designed,the loop consisting of C1(s)and G(s)is viewed as an augmented plant,of which the transfer function is denoted by T(s).The system that consists of C2(s) and T(s)forms the IMC structure with an exact model. Accordingly,C2(s)can be directly designed To illustrate the design procedure,consider the following plant: G(s= T5+1 The system is required to track a step reference,and at the same time to reject the disturbance that is in the form of a ramp at the plant output 4口，+@，4定4定90C Zhang.W.D..CRC Press.2011 Version 1.0 8/95Section 9.1 The 2DOF Structure for Stable Plants C1(s): The design of C1(s) is the same as that for the controller in a 1DOF system C2(s): After C1(s) is designed, the loop consisting of C1(s) and G(s) is viewed as an augmented plant, of which the transfer function is denoted by T(s). The system that consists of C2(s) and T(s) forms the IMC structure with an exact model. Accordingly, C2(s) can be directly designed To illustrate the design procedure, consider the following plant: G(s) = K τ s + 1 e −θs The system is required to track a step reference, and at the same time to reject the disturbance that is in the form of a ramp at the plant output Zhang, W.D., CRC Press, 2011 Version 1.0 8/95