ntre Table 1-1 Summary of MPC signals(see also Figure 1-1). Symbol Description d Unmeasured disturbance. a disturbance unknown to MPC that affects the plant output. MPC provides feedback compensation r Setpoint (or reference signal). The target value for the Actuator (or manipulated variable). The signal MPC adjusts in order to achieve its control objectives Measured disturbance(optional). MPC feedforward compensation adjusts for such disturbances as they occur to minimize their impact on the controlled variable Controlled variable( or plant output). The signal to be held at the setpoint. This is the"true"value, uncorrupted by measurement noise Measurement of the controlled variable. Used to estimate the true value, y z Measurement noise Represents electrical noise, sampling errors,drifting calibration, and other effects that reduce the accuracy of the measurement The measured disturbance also affects y. The MPC block includes models of the way in which v and u affect y(symbolically, v-y and u-y). It uses this information to calculate u adjustments that keep y at its setpoint in spite of the(known)disturbance. This calculation considers the effect of any known constraints on the adjustments(e.g,an actuator at its upper or lower bound). If the models are accurate and the plant responds quickly to u, this"feedforward" compensation counteracts the effect of v perfectly1 Introduction 1-6 The measured disturbance also affects . The MPC block includes models of the way in which v and u affect (symbolically, and ). It uses this information to calculate u adjustments that keep at its setpoint in spite of the (known) disturbance. This calculation considers the effect of any known constraints on the adjustments (e.g., an actuator at its upper or lower bound). If the models are accurate and the plant responds quickly to u, this “feedforward” compensation counteracts the effect of v perfectly. Table 1-1 Summary of MPC signals (see also Figure 1-1). Symbol Description d Unmeasured disturbance. A disturbance unknown to MPC that affects the plant output. MPC provides feedback compensation for such disturbances. r Setpoint (or reference signal). The target value for the controlled variable. u Actuator (or manipulated variable). The signal MPC adjusts in order to achieve its control objectives. v Measured disturbance (optional). MPC feedforward compensation adjusts for such disturbances as they occur to minimize their impact on the controlled variable. Controlled variable (or plant output). The signal to be held at the setpoint. This is the “true” value, uncorrupted by measurement noise. y Measurement of the controlled variable. Used to estimate the true value, . z Measurement noise. Represents electrical noise, sampling errors, drifting calibration, and other effects that reduce the accuracy of the measurement. y y y y v y ® u y ® y