LiftMotor_Flyer_v8

Platform: STM32G431CBTx (ARM Cortex-M4, 170 MHz)
Machine: Flyer Frame (FF) — Left Lift & Right Lift axes
Firmware: v8
Part No: CUST-0015 (Motor 300W-GS-LIBD)

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What This Firmware Does

Controls a BLDC motor that drives a lead-screw lift mechanism on the Flyer Frame machine. Two identical boards run the same firmware — one for Left Lift (CAN ID 4) and one for Right Lift (CAN ID 5).

The lift moves the bobbin carriage up and down in a traverse stroke pattern during winding. The firmware supports open-loop (duty-cycle) and closed-loop (position) control using two encoders — a 14-bit SPI motor encoder and a PWM gearbox encoder.

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Hardware

Component	Device	Purpose
MCU	STM32G431CBTx	Runs all firmware
Motor Driver	BLDC Drive 48V / ~12A	Drives motor phases U, V, W
Motor Encoder	AS5x47P 14-bit SPI (16384 cnt/rev)	Shaft angle for commutation + calibration
Gearbox Encoder	PWM absolute encoder TIM3 (45265 cnt/rev)	Lead-screw absolute position (80.6:1 ratio)
Speed Encoder	TIM2 quadrature (2048 cnt/rev)	RPM feedback for PID
Position Resolution	140 TIM3 counts per mm	Stroke position accuracy
EEPROM	I2C (hi2c1)	Stores PID, offsets, CAN ID, homing, GB bin errors
CAN	FDCAN 1 Mbit/s	Communication with Flyer MainBoard
Console	UART3 115200 baud	Service menu via USB-UART programmer
Position Loop	TIM16 40 ms periodic	Closed-loop position control execution
LOB Watchdog	TIM17	Lift out-of-bounds safety watchdog

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How a Stroke Works

MainBoard sends LIFT_SETUP (distance, time, direction) over CAN
  └─> Firmware sets up trapezoid velocity profile (PosCntrl)
  └─> MainBoard sends LIFT_NEW_STROKE command
  └─> Motor ramps up following velocity profile
  └─> Position tracked via both GB encoder and motor encoder
  └─> PID corrects error between target and actual GB position
  └─> Motor ramps down → stops at target distance
  └─> Stroke complete → IDLE_STATE

MainBoard sends RAMPDOWN_STOP at any time
  └─> Motor ramps down and stops
  └─> Returns to IDLE_STATE

Closed-Loop Position Control

• Velocity profile: Trapezoid — ramp up → cruise → ramp down
• Primary feedback: Gearbox (GB) PWM encoder — absolute position in mm
• Secondary feedback: Motor encoder — cross-checks GB position
• PID error: targetStrokePos − GBActualStroke
• Position loop rate: Every 40 ms (TIM16 interrupt)
• Velocity range: 1.5 – 4.0 mm/s (set by stroke time input)

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Motor States

State	Description
IDLE_STATE	Motor stopped. Accepts CAN commands and console trigger
RUN_STATE	Stroke in progress — open-loop or closed-loop
ERROR_STATE	Fault active. Motor stopped. Console accessible for diagnosis
CONFIG_STATE	Console active (blocking). CAN commands ignored
CALIBRATION_STATE	Motor encoder calibration — 30-step blocking routine
HOMING_STATE	Gearbox homing routine in progress
PAUSE_STATE	Stroke paused mid-run. Resumable via CAN RESUME

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EEPROM Parameters

Parameter	Address	Default	Description
Kp	0x02	0	PID proportional gain
Ki	0x06	0	PID integral gain
start_offset	0x0A	100	PWM offset at motor startup
ff_percent	0x0C	10	Feed-forward % of target velocity
MOTID	0x10	—	CAN node ID (4 = Left Lift, 5 = Right Lift)
AMS_offset_index	0x12	—	Encoder zero from calibration routine
default_direction	0x14	0 (CW)	CW = DOWN, CCW = UP for lift motors
LIFT_HOMING_POSITION	0x16	—	GB PWM count at physical home (≈ 6–7% duty)
GEARBOX_ERROR_VALUE	0x20	0.0	21-bin correction table (float × 21 = 84 bytes)

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CAN Interface

Function ID	Direction	Description
0x01	Motor → MB	Motor state byte
0x02	Motor → MB	Error bitmask (all fault bits)
0x09	Motor → MB	Runtime data (position, RPM, current, voltage)
0x10	MB → Motor	Lift stroke setup: distance, time, direction
0x15	MB → Motor	New stroke start command
0x16	MB → Motor	Request gearbox position data
0x17	Motor → MB	Gearbox position data response
0x06	MB → Motor	PID tuning update (Kp, Ki, FF, StartOffset)

CAN Node IDs:

Motor	CAN ID
Left Lift	0x04
Right Lift	0x05

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New Motor Commissioning (Console)

Connect programmer to UART3, open terminal at 115200 baud, trigger console with $$$$ (Shift+4 four times). Motor must be in IDLE_STATE.

Step	Option	Action	Note
1	Option 2	Set CAN ID (4 = Left, 5 = Right)	Save + Restart (Option 14)
2	Option 4	Set direction — CW (0) = DOWN	Save + Restart
3	Option 6	Run encoder calibration — gearbox must NOT be assembled	Record encIndex_wOffset
4	Option 3	Save encIndex_wOffset to EEPROM	Restart + verify via Option 1
5	—	Assemble gearbox. Refit lead screw — no nut yet
6	Option 7	Gearbox homing — jog until GB duty = 6–7%, save	Restart
7	Option 12	Open-loop run DOWN 300 mm to GB count ≈ 45000	Prep for calibration
8	Option 8	Gearbox calibration — run full stroke, check all bins ±15, save	Refit nut after
9	Option 11	Closed-loop test — 50 mm UP in 20 s	Verify tracking within ±5%
10	Option 13	Sync encoder abs position to GB position (press 2)

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Gearbox Calibration — How It Works

The gearbox PWM encoder has position-dependent errors. The firmware maps these across 21 bins (each = 15 mm of travel) and stores a correction table in EEPROM.

• Motor runs UP from GB count ≈ 45000 → 0 (full stroke)
• Each bin records: Average_Error = GB_reading − Motor_encoder_reading
• Correction applied in real time during closed-loop strokes
• All 21 bins must be within ±15.0 — values outside this = mechanical problem

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Error Codes

Bit	Fault	Recovery
1	Over-current (> 12A)	Check load and wiring
2	Over-voltage (> 50V)	Check PSU
3	Under-voltage (< 40V)	Check PSU under load
4	Motor thermistor fault	Check NTC wiring (10kΩ @ 25°C)
5	FET thermistor fault	Check FET NTC wiring
6	Motor over-temperature	Allow cool-down, check airflow
7	FET over-temperature	Check heatsink + thermal paste
8	EEPROM write error	Check I2C bus
9	EEPROM bad value at boot	Re-enter all settings, restart
10	Tracking error	Re-tune PID (Option 5)
11	Motor encoder setup fail	Check SPI wiring + magnet gap
12	Lift position tracking error	Re-run gearbox calibration (Option 8)
13	Lift synchronicity fail	Resync via Option 13
14	Lift out of bounds (LOB)	Use Option 10 to jog to safe position
15	EEPROM bad homing position	Re-run homing (Option 7)

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Console Menu Summary

Option	Name	When to Use
1	View Settings	First check in any session — reads all EEPROM + live sensor values
2	Change CAN ID	New motor or CAN conflict
3	Change Encoder Offset	After encoder calibration (Option 6)
4	Change Direction	Wrong rotation direction
5	PID Settings	Tuning — Kp, Ki, FF%, StartOffset
6	Encoder Calibration	Mandatory for new motor — shaft must be free
7	Gearbox Homing	Set physical home reference position
8	Gearbox Calibration	Map 21-bin error correction table
9	GB Bin Management	View or zero bin error table
10	Toggle LOB Limit	Engineering only — disable out-of-bounds check
11	Run Closed-Loop	Position-controlled stroke test
12	Run Open-Loop	Manual jog — duty-cycle controlled
13	Zero EncAbsPosition	Sync motor encoder to gearbox position
14	Restart Motor Code	Always run after saving any EEPROM value

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Build

• IDE: STM32CubeIDE
• Import project → Build (Ctrl+B)
• Flash with ST-LINK V2 via SWD or STM32CubeProgrammer (.elf / .hex)
• Do not regenerate the .ioc file without engineering review