Attitude Control Lab 1

ntut-attitude-lab1.py

"""
ntut-lab1.py
Sets initial conditions for a spacecraft in Basilisk 2.4.0.
"""

from Basilisk.simulation import spacecraft
from Basilisk.utilities import SimulationBaseClass, macros
import matplotlib.pyplot as plt

# Create simulation base
sim = SimulationBaseClass.SimBaseClass()
simProcessName = "process1"
simTaskName = "task1"


dynamicsProcess = sim.CreateNewProcess(simProcessName)
dynamicsProcess.addTask(sim.CreateNewTask(simTaskName, macros.sec2nano(0.1)))

# Create spacecraft object
scObject = spacecraft.Spacecraft()
scObject.ModelTag = "spacecraftBody"

# Set initial conditions directly
scObject.hub.r_CN_NInit = [0.0, 0.0, 0.0]        # Initial position vector [m]
scObject.hub.v_CN_NInit = [0.0, 0.0, 0.0]        # Initial velocity vector [m/s]
scObject.hub.sigma_BNInit = [0.0, 0.0, 0.0]      # Initial MRP attitude
scObject.hub.omega_BN_BInit = [0.1, 0.1, 0.0]    # Initial body rates [rad/s]

# Add spacecraft object to the simulation
sim.AddModelToTask(simTaskName, scObject)

# Log spacecraft state
scLog = scObject.scStateOutMsg.recorder()
sim.AddModelToTask(simTaskName, scLog)

# Run simulation
sim.InitializeSimulation()
sim.ConfigureStopTime(macros.sec2nano(600))  # Simulate 600 seconds
sim.ExecuteSimulation()

# Retrieve logged data
time = scLog.times() * macros.NANO2SEC
omega = scLog.omega_BN_B

# Plot angular velocity
plt.figure()
plt.plot(time, omega[:, 0], label='ω_x')
plt.plot(time, omega[:, 1], label='ω_y')
plt.plot(time, omega[:, 2], label='ω_z')
plt.xlabel("Time [s]")
plt.ylabel("Angular Velocity [rad/s]")
plt.title("Spacecraft Angular Velocity")
plt.legend()
plt.grid()
plt.tight_layout()
plt.show()