- 3.2 CoDR Checklist Kareena Shah
- 5.2 CoDR Checklist Sreeja Akula
- 3.2 (Thermal Equalization) Thermal Strap Analysis Divya Krishna
- 4.1 (Rotational Dynamics and Updated Torque Calcs) Izaan Rizvi @Colter Adrian Yang Elisha Aranibar
- 4.1 (Tank and Propellant Pressure Analysis) Brandon Garcia @Rene
3.2
-kareena
4.1 -
4.1 Design Book MCU Specs:
- Frequency up to 480 Mhz
- 2 Mbytes of flash memory
- 1 Mbyte of RAM
- 3x 16-bit ADC
- STM32H753 VI →
- Number of Direct channels - 3
- Number of Fast channels - 2
- Number of Slow channels -11
- STM32H753 ZI →
- Number of Direct channels - 2
- Number of Fast channels - 9
- Number of Slow channels -17
- STM32H753 AI/STM32H753 II /STM32H753 BI →
- Number of Direct channels - 2
- Number of Fast channels - 9
- Number of Slow channels -21
- STM32H753 XI →
- Number of Direct channels - 4
- Number of Fast channels - 9
- Number of Slow channels -23
- STM32H753 VI →
- –40 to +85 °C temperature range from a 1.62 to 3.6 V power supply
- 4x I 2Cs– 4x USARTs, 4x UARTs and 1x LPUART
- a high-resolution timer, 12 general-purpose 16-bit timers, two PWM timers for motor control, five low-power timers
Rigid-Body Rotational Dynamics (Tank Spin System):
Tank Specs:
Material → 304L Stainless Steel
Length → 15 cm
Radius → 4 cm
Thickness → 0.5 cm
Mass → 1.143 kg
Configuration:
Thin-walled cylindrical tank approximation
Instrumented with internal thermocouples
Sealed end-cap with wiring feedthrough
Moment of Inertia (Izz):
Izz = mR²
Izz = (1.143 kg)(0.04 m)²
Izz = 0.001829 kg·m²
Drive Torque:
τ = 0.840 N·m
Angular Acceleration:
τ = Iα → α = τ / I
α ≈ 459.4 rad/s²
Spin Rate Requirement:
2–3 RPM
ω ≈ 12.57 – 18.85 rad/s
Spin-Up Time:
t = ω / α
t ≈ 27 – 41 ms
Power Estimate:
P ≈ 6.5 W
Motor / Servo Notes:
Torque–speed curve limits max RPM
Servo must provide ≥ 0.84 N·m stall torque
Continuous power ≥ 6.5 W
Design Task:
Evaluate 4 candidate servos from electrical spreadsheet →
Compare torque, speed, power, and mass to select optimal model.
4.2
4.3
5.1
Sensor Inventory
The sensor suite must be finalized for CoDR and justified, including:
IMU (gyroscopes and accelerometers
- ignore
Redundant rate sensing
- 2 pressure sensors
Tank temperature sensor array
- Custom from WIKA
Pump RPM and motor current sensing
- ignore
Pressure and vent-state sensing
- ignore
5.2
For each sensor, Controls shall specify:
Update rate
Accuracy and noise
Drift characteristics
Survivability under spin
Electrical interface
5.3
- Max Operating Temperatures of Components (C):
- Tank Servos: max coil temp → 130, continuous (preferable) operating temp → 90
- On Board Computer (OBC): -40 to 85 (assuming power supply 1.62V to 3.6V)
- Pressure Sensor: -40 to 125
- Watchdog timer circuit: -40 to 125
- Thermocouple to digital converter: -55 to 125
- RS-422 Transceiver Bus/Data: -65 to 150 (storage temperature), 150 max junction temperature, **highly recommended: -40 to 85
- Thermal strap details: STCH_Thermal Straps_Submitted_Q2 2024.pdf
7.1 -
| Failure Mode | Detection | Isolation / Safe Mode | Recovery |
|---|---|---|---|
| Sensor bias / dropout | Redundancy, out-of-range checks, rate checks, residuals | Flag sensor invalidity, use backup, and reduce authoriuty | Sensor reset → offset compensation where valid |
| Unexpected torque | Model vs measured residuals | Switch to damping mode, inhibit impulses | Let residuals decay and re-estimate states |
| Spin-axis misalignment | Orientation vs expected dynamics | Reduce authority, re-acquisition | Re-estimate axis and update control parameters |
| Partial power loss | Voltage / Current thresholds | Disable non-essential processes and maintain survival | Gradually restore functions as power stabilizes |
FDIR = Continuously:
Observe system state
Compare to model/expectations
Flag anomalies
Enter a safe mode
Attempt recovery
Only return to nominal when consistent