现代操纵理论演示课件.ppt

(Foundation of)  Modern Control Theory 0. Introduction 0.1. What？ -how？ -why？ An example（process control shown by block diagram） Output Y(controlled variable )-process( controlled object, plant )-actuator-power amplifier (open-loop control, Manual/automatic )-disturbance input-controller-sensor(f1)-reference input (R)-Difference(R-f1) 0.2.Typically think of closed-loop control→ so we would analyze the closed-loop dynamics –Open-loop control also possible( called “feedforward”)–more prone to modeling errors since inputs not changed as a result of measured error. Open loop control system. A system in which the output has no effect upon the input signal Closed-loop control system. A system in which the output has an effect upon the input quantity in such a manner as to maintain the desired output value. 0.3. Goal: Design a controller Gc(s) so that the system has some desired characteristics. Typical objectives: -Stabilize the system (Stabilization) –Regulate the system about some design point (Regulation) –Follow a given class of command signals (Tracking) -Reduce response to disturbances. (Disturbance Rejection) 0.4.Note that a typical control system includes the sensors, actuators, and the control law. –The sensors and actuators need not always be physical devices (e.g., economic systems). –A good selection of the sensor and actuator can greatly simplify the control design process. –Course concentrates on the design of the control law given the rest of the system( although we will need to model the system). 0.5.Feedback Control Approach? 0.5.1.Establish control objectives –Qualitative–don’t use too much fuel –Quantitative–settling time of step response3sec –Typically requires that you understand the process (expected commands and disturbances) and the overall goals (bandwidths). –Often requires that you have a strong understanding of the physical dynamics of the system so that you do not “fight” them in inappropriate (i.e., inefficient ) way