控制工程6（英文）The Design of Feedback Control Systems培训资料.pptVIP

Ch10 The Design of Feedback Control Systems;10.1 Introduction;Types of compensation;;10.2 Approach to system design ;;;The TF of phase-lead compensation;;;;The TF of phase-lag compensation;;;10.4 Phase-lead design using Bode diagram ;Design procedure;4 Evaluate 10loga and determine the frequency where the uncompensated magnitude curve is -10loga dB. This frequency is the new 0-dB crossover frequency and . 5 Calculate the pole and zero 6 Draw the compensated frequency response,check the resulting phase margin, and repeated the steps if unsatisfying. Finally, raise the gain of the amplifier in order to account for the attenuation . ;Design example;;A lead compensator for a second-order system;Design procedure;3.Determine the frequency where the phase margin requirement would be satisfied if the magnitude curve crossed the 0-dBline at this frequency, .(Allow for phase lag from the phase-lag network when determining the new crossover frequency.) 4.Place the zero of the compensator one decade below the new crossover frequency and thus ensure only of additional phase lag at due to the lag network. 5.Measure the necessary attenuation at to ensure that the magnitude curve crosses at this frequency. 6.Calculate a by noting that the attenuation introduced by the phase-lag network is -20 log a at . 7.Calculate the pole as = . ;Design example;;It is evident that the phase lag introduces an attenuation that lowers the crossover frequency and therefore increase the phase margin.;;Summary; When large error constants are specified for a feedback system, it is usually easier to compensate the system by using integration (phase-lag) networks. We also noted that the phase-lead compensation increases the system bandwidth, whereas the phase-lag compensation decreases the system bandwidth. The bandwidth may often be an important factor when noise is present at the input and generated within the system. Also we noted that a sati