PlotDemo/plot_pade.py at master · tnakaicode/PlotDemo · GitHub

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import matplotlib.pyplot as plt
import numpy as np
from control import matlab

from base import plot2d

# pade近似を表現,前提として5秒のむだ時間を設定
# まずパデ近似の分子、分母を求める
num2, dem2 = matlab.pade(5, 2)
num4, dem4 = matlab.pade(5, 4)
num6, dem6 = matlab.pade(5, 6)
num8, dem8 = matlab.pade(5, 8)
num10, dem10 = matlab.pade(5, 10)
# pade近似の分子、分母を伝達関数の形に変換
P2 = matlab.tf(num2, dem2)
P4 = matlab.tf(num4, dem4)
P6 = matlab.tf(num6, dem6)
P8 = matlab.tf(num8, dem8)
P10 = matlab.tf(num10, dem10)
# 最後にstep応答を行う
time = 100
t = np.linspace(0, time, 1000)
y2, T = matlab.step(P2, t)
y4, T = matlab.step(P4, t)
y6, T = matlab.step(P6, t)
y8, T = matlab.step(P8, t)
y10, T = matlab.step(P10, t)

obj = plot2d()
obj.axs.set_aspect('auto')
plt.plot(T, y2, label="2")
plt.plot(T, y4, label="4")
plt.plot(T, y6, label="6")
plt.plot(T, y8, label="8")
plt.plot(T, y10, label="10")
plt.xlim((1, 15))
plt.ylim((-0.50, 1.1))
plt.xlabel("Time[sec.]")
plt.ylabel("y(t)")
plt.legend()
obj.SavePng()