Tham khảo tài liệu 'bishop, robert h. - the mechatronics handbook [crc press 2002] part 13', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | FIGURE Polar plots of system with various system types as O 0. FIGURE Polar plots of system with various relative degrees as O ra. We will see that for a closed-loop system the polar plot of the loop transfer function is useful in determining the stability of the system. The polar plots of some simple systems are shown in Fig. . Log-Magnitude Versus Phase Plots Another approach to presenting the frequency response of a system by a single graph is to plot its logarithmic magnitude versus the phase angle over a frequency range of interest. The resulting curve is a function of the frequency O. Such log-magnitude versus phase plots are called Nichols charts. Advantages of the Nichols chart are that the relative stability of the closed-loop system can be determined quickly and that the process of closed-loop compensation can be carried out easily. The Nichols charts of the systems in Fig. are depicted in Fig. for comparison. Figure displays three different frequency-response curves of the second-order system 2 a G s s 2 Q iJns On 2002 CRC Press LLC FIGURE Polar plots of system with various system types as O 0. FIGURE Polar plots of system with various relative degrees as O ra. We will see that for a closed-loop system the polar plot of the loop transfer function is useful in determining the stability of the system. The polar plots of some simple systems are shown in Fig. . Log-Magnitude Versus Phase Plots Another approach to presenting the frequency response of a system by a single graph is to plot its logarithmic magnitude versus the phase angle over a frequency range of interest. The resulting curve is a function of the frequency O. Such log-magnitude versus phase plots are called Nichols charts. Advantages of the Nichols chart are that the relative stability of the closed-loop system can be determined quickly and that the process of closed-loop compensation can be carried out easily. The Nichols charts of the .
