My projects
Engineering Work
End-to-End 3U CubeSat ADCS & Mission Simulation
A complete attitude determination and control system (ADCS) mission architecture simulated in MATLAB and Simulink. The spacecraft autonomously switches between ground-tracking and solar-pointing modes, implements realistic actuator constraints, and handles environmental disturbances with momentum dumping.
- Pointed the spacecraft's +Z body axis toward USU (Logan, UT) during communication windows ≥10° above horizon
- Secondary constraint: align +Y body axis with orbit angular momentum vector during ground contact
- Sun-pointing mode outside ground passes with +X axis as secondary angular momentum constraint
- Inner loop proportional controller: gain crossover ~6.7 Hz, 65.5° phase margin, 11.3 dB gain margin
Inner loop frequency & step response ▼
Open loop Bode w/ control gain
Closed loop Bode w/ control
Closed loop step response
- Outer loop integrator/lead compensator: 2.8 Hz crossover, zero overshoot, 62.7° phase margin
Outer loop frequency & step response ▼
Outer open loop Bode
Outer closed loop Bode
Outer closed loop step response
- Trapezoidal trajectory profiling with command feedforward to minimize tracking error
Trapezoidal trajectory & feedforward results ▼
Error angle (θe)
Angular momentum hw_B
Torque ḣw_B
Quaternion q_BI
- Reaction wheel saturation handling with anti-windup and proportional switching near limits
- Momentum dumping via magnetic torque rods using a scaled M* approach
Momentum dumping results ▼
Open loop Bode
Step error rejection
Commanded magnetic moment (A·m²)
Reaction wheel angular momentum
- EGM2008 gravity field, atmospheric drag, solar radiation pressure, and gravity gradient torques modeled
- World Magnetic Model 2020 + eclipse detection via Julian Date sun vector calculation
Disturbance torque model ▼
Gravity gradient torque implementation (3μ/r³ · n × J·n)
Quaternion Attitude Estimation via Kalman Filter
A spacecraft attitude estimation system using a Kalman filter to track orientation and angular velocity while compensating for gyroscope bias and noisy measurements. The filter converges rapidly to steady-state bias estimates and provides smooth angular velocity outputs.
- Quaternion-based state vector with gyroscope bias augmentation
- Measurement updates from two vector sensor sources sampled at different rates
- Filter tracks attitude closely, including after a large attitude change near the 40-second mark
- Biases converge to steady state quickly; estimated and true quaternions align through simulation
- Kalman smoothing visibly reduces input noise on angular velocity signals
Filter performance figures ▼
Angle tracking — vector 1
q̂_bi vs q_bi
Gyroscope bias convergence
Raw vs filtered ω_bi
Nested Inner/Outer Loop Controller Design
A two-loop cascaded control architecture for a 3U CubeSat driven by a Blue Canyon Technologies XACT reaction wheel assembly. Designed for step, ramp, sine, and disturbance inputs with full frequency-domain stability analysis.
- Second-order actuator model: 10 Hz natural frequency, √2/2 damping, 10 ms system delay
- Steady-state ramp error analytically shown to be zero via final value theorem
- Zero overshoot on outer loop step response; disturbance attenuated within ~500 s
- Sine tracking at 3.48 rad/s near-perfect amplitude match with expected phase lag
- Implementation of design onto hardware using C++ and sending data for modeling via UDP traffic in Simulink
Impedance of Plasma-Filled Capacitors in a Magnetized Anisotropic Cold Plasma
Numerical and analytical analysis of a Langmuir probe in cylindrical and spherical geometries using MATLAB's PDE Toolbox.
- Mesh objects in MATLAB with multiple faces for cylindrical and spherical probe geometries
- PDE Toolbox used to simulate plasma density and RF frequency hitting the probe face at varying angles
- Analytical equations implemented for comparison between expected and simulated impedance values
Probe geometry models ▼
Cylindrical mesh model
Spherical mesh model
Impedance results at 8 MHz ▼
Cylindrical — 8 MHz
Spherical — 8 MHz