145 lines
3.6 KiB
Python
145 lines
3.6 KiB
Python
'''
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Filename: 12_EulerEKF.py
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Created on: April,10, 2021
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Author: dhpark
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'''
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import numpy as np
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from numpy.linalg import inv
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import matplotlib.pyplot as plt
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from math import cos, sin, tan, asin, pi
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from scipy import io
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import pandas as pd
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def GetData(i, data):
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x = data[0][i] # (41500, 1)
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y = data[1][i] # (41500, 1)
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z = data[2][i] # (41500, 1)
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return x, y, z
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def EulerAccel(ax, ay, az):
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g = 90000.8 # 9.8
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print(ax)
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print(g)
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theta = asin(ax / g)
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phi = asin(-ay / (g * cos(theta)))
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return phi, theta
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def sec(theta):
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return 1/cos(theta)
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def Ajacob(xhat, rates, dt):
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'''
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:param xhat: State Variables(phi, theta, psi)
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:param rates: angel speed(p,q,r)
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:param dt: variable to make discrete form
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'''
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A = np.zeros([3,3])
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phi = xhat[0]
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theta = xhat[1]
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p,q,r = rates[0], rates[1], rates[2]
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A[0][0] = q * cos(phi)*tan(theta) - r*sin(phi)*tan(theta)
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A[0][1] = q * sin(phi)*(sec(theta)**2) + r*cos(phi)*(sec(theta)**2)
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A[0][2] = 0
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A[1][0] = -q * sin(phi) - r * cos(phi)
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A[1][1] = 0
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A[1][2] = 0
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A[2][0] = q * cos(phi) * sec(theta) - r * sin(phi) * sec(theta)
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A[2][1] = q * sin(phi) * sec(theta)*tan(theta) + r*cos(phi)*sec(theta)*tan(theta)
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A[2][2] = 0
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A = np.eye(3) + A*dt
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return A
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def fx(xhat, rates, dt):
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phi = xhat[0]
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theta = xhat[1]
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p,q,r = rates[0], rates[1], rates[2]
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xdot = np.zeros([3,1])
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xdot[0] = p + q * sin(phi) * tan(theta) + r * cos(phi)*tan(theta)
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xdot[1] = q * cos(phi) - r * sin(phi)
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xdot[2] = q * sin(phi)*sec(theta) + r * cos(phi) * sec(theta)
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xp = xhat.reshape(-1,1) + xdot*dt # xhat : (3,) --> (3,1)
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return xp
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def EulerEKF(z, rates, dt):
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global firstRun
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global Q, H, R
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global x, P
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if firstRun:
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H = np.array([[1,0,0],[0,1,0]])
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Q = np.array([[0.0001,0,0],[0,0.0001,0],[0,0,0.1]])
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R = 10 * np.eye(2)
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x = np.array([0, 0, 0]).transpose()
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P = 10 * np.eye(3)
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firstRun = False
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else:
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A = Ajacob(x, rates, dt)
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Xp = fx(x, rates, dt) # Xp : State Variable Prediction
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Pp = A @ P @ A.T + Q # Error Covariance Prediction
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K = (Pp @ H.T) @ inv(H@Pp@H.T + R) # K : Kalman Gain
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x = Xp + K@(z.reshape(-1,1) - H@Xp) # Update State Variable Estimation
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P = Pp - K@H@Pp # Update Error Covariance Estimation
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phi = x[0]
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theta = x[1]
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psi = x[2]
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return phi, theta, psi
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H, Q, R = None, None, None
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x, P = None, None
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firstRun = True
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df = pd.read_csv('raw_data_6d.xls', sep='\t')
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gyro_data = [list(df['%GyroX'].values), list(df['GyroY'].values), list(df['GyroZ'].values)]
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acce_data = [list(df['AcceX'].values), list(df['AcceY'].values), list(df['AcceZ'].values)]
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Nsamples = len(df)
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EulerSaved = np.zeros([Nsamples,3])
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dt = 0.01
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for k in range(Nsamples):
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p, q, r = GetData(k, gyro_data)
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ax, ay, az = GetData(k, acce_data)
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phi_a, theta_a = EulerAccel(ax, ay, az)
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phi, theta, psi = EulerEKF(np.array([phi_a, theta_a]).T, [p,q,r], dt)
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if type(phi) == type(np.array([])):
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EulerSaved[k] = [phi[0], theta[0], psi[0]]
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else:
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EulerSaved[k] = [phi, theta, psi]
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t = np.arange(0, Nsamples * dt ,dt)
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PhiSaved = EulerSaved[:,0] * 180/pi
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ThetaSaved = EulerSaved[:,1] * 180/pi
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PsiSaved = EulerSaved[:,2] * 180/pi
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plt.figure()
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plt.plot(t, PhiSaved)
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plt.xlabel('Time [Sec]')
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plt.ylabel('Roll angle [deg]')
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plt.savefig('12_EulerEKF_roll.png')
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plt.figure()
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plt.plot(t, ThetaSaved)
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plt.xlabel('Time [Sec]')
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plt.ylabel('Pitch angle [deg]')
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plt.savefig('12_EulerEKF_pitch.png')
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plt.show()
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'''
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plt.subplot(133)
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plt.plot(t, PsiSaved)
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plt.xlabel('Time [Sec]')
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plt.ylabel('Psi angle [deg]')
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''' |