Add hw_button driver (PC2 active-low, 20ms debounce) with gesture detection:
- Single short press + 500ms quiet -> BTN_EVENT_PARK
- SHORT+SHORT+LONG combo (within 3s) -> BTN_EVENT_REARM_COMBO
New BALANCE_PARKED state: PID frozen, motors off, quick re-arm via button
combo without the 3-second arm interlock required from DISARMED.
FC_BTN (0x404) CAN frame sent to Orin on each event:
event_id 1=PARKED, 2=UNPARKED, 3=UNPARK_FAILED (pitch > 20 deg)
Includes 11 unit tests (1016 assertions) exercising debounce, bounce
rejection, short/long classification, sequence detection, and timeout.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Adds a slow-adapting terrain slope estimator (IIR tau=5s) that decouples
the robot's balance offset from genuine ground incline. The balance
controller subtracts the slope estimate from measured pitch so the PID
balances around the slope surface rather than absolute vertical.
- include/slope_estimator.h + src/slope_estimator.c: first-order IIR
filter clamped to ±15°; JLINK_TLM_SLOPE (0x88) telemetry at 1 Hz
- include/jlink.h + src/jlink.c: add JLINK_TLM_SLOPE (0x88),
jlink_tlm_slope_t (4 bytes), jlink_send_slope_tlm()
- include/balance.h + src/balance.c: integrate slope_estimator into
balance_t; update, reset on tilt-fault and disarm
- test/test_slope_estimator.c: 35 unit tests, all passing
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
