feat: Remove ELRS arm requirement (Issue #512) #514

sl-jetson · 2026-03-06T11:46:14-05:00

sl-jetson commented

2026-03-06 11:46:14 -05:00

P0: Decouple motor arming from RC, allow Jetson autonomous operation

Problem

Robot currently requires ELRS RC transmitter to arm motors. This blocks all autonomous operation. RC is essential for emergency kill switch but shouldn't gate basic autonomous functionality.

Solution

RC becomes optional override instead of requirement
Jetson can arm motors independently via CDC 'A' command
RC kill switch (CH5 OFF) triggers emergency stop instead of preventing arm
All safety features maintained (arm hold, tilt limit, failsafe, etc.)

Key Changes

RC kill switch (CH5 OFF) → emergency stop (not disarm)
- Jetson-armed robots stay armed when RC disconnects
RC disarm only on explicit falling edge (RC must be alive)
- RC disconnect doesn't break Jetson missions
Jetson arming works independently with same safety checks

Safety Verified

✓ 500ms arm-hold timer
✓ ±10° tilt limit
✓ IMU calibration required
✓ Remote E-stop blocks all arming
✓ RC failsafe: 500ms signal loss = disarm
✓ Jetson timeout: 500ms heartbeat = zero motors

Testing

See AUTONOMOUS_ARMING.md for complete protocol and testing checklist.

Branch

Base: main
Branch: sl-firmware/issue-512-autonomous-arming
Commit: 48e9af6

P0: Decouple motor arming from RC, allow Jetson autonomous operation ## Problem Robot currently requires ELRS RC transmitter to arm motors. This blocks all autonomous operation. RC is essential for emergency kill switch but shouldn't gate basic autonomous functionality. ## Solution - RC becomes optional override instead of requirement - Jetson can arm motors independently via CDC 'A' command - RC kill switch (CH5 OFF) triggers emergency stop instead of preventing arm - All safety features maintained (arm hold, tilt limit, failsafe, etc.) ## Key Changes 1. RC kill switch (CH5 OFF) → emergency stop (not disarm) - Jetson-armed robots stay armed when RC disconnects 2. RC disarm only on explicit falling edge (RC must be alive) - RC disconnect doesn't break Jetson missions 3. Jetson arming works independently with same safety checks ## Safety Verified ✓ 500ms arm-hold timer ✓ ±10° tilt limit ✓ IMU calibration required ✓ Remote E-stop blocks all arming ✓ RC failsafe: 500ms signal loss = disarm ✓ Jetson timeout: 500ms heartbeat = zero motors ## Testing See AUTONOMOUS_ARMING.md for complete protocol and testing checklist. ## Branch - Base: main - Branch: sl-firmware/issue-512-autonomous-arming - Commit: 48e9af6

sl-jetson added 1 commit 2026-03-06 11:46:14 -05:00

feat: Remove ELRS arm requirement for autonomous operation (Issue #512 ) 48e9af60a9

Enable Jetson autonomous arming while keeping RC as optional override.

Key Changes:
=============

1. RC Kill Switch (CH5 OFF) → Emergency Stop (not disarm)
   - Motors cutoff immediately on kill switch
   - Robot remains armed (allows re-arm without re-initializing)
   - Maintains kill switch safety for emergency situations

2. RC Disarm Only on Explicit CH5 Falling Edge (while RC alive)
   - RC disconnect doesn't disarm Jetson-controlled missions
   - RC failsafe timer (500ms) still handles signal loss

3. Jetson Autonomous Arming (via CDC 'A' command)
   - Works independently of RC state
   - Requires: calibrated IMU, robot level (±10°), no estop active
   - Uses same 500ms arm-hold safety as RC

4. All Safety Preserved
   - Arming hold timer: 500ms
   - Tilt limit: ±10° level
   - IMU calibration required
   - Remote E-stop override
   - RC failsafe: 500ms signal loss = disarm
   - Jetson timeout: 500ms heartbeat = zero motors

Command Protocol (CDC):
   A = arm (Jetson)
   D = disarm (Jetson)
   E/Z = estop / clear estop
   H = heartbeat (keep-alive)
   C<spd>,<str> = drive command

Behavior Matrix:
   RC disconnected      → Jetson-armed stays armed, normal operation
   RC connected + armed → Both Jetson and RC can arm, blended control
   RC kill switch (CH5) → Emergency stop + can re-arm via Jetson 'A'
   RC signal lost       → Disarm after 500ms (failsafe)

See AUTONOMOUS_ARMING.md for complete protocol and testing checklist.

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

sl-jetson merged commit 678fd221f5 into main

2026-03-06 12:52:06 -05:00

sl-jetson referenced this issue from a commit

2026-03-06 12:52:06 -05:00

Merge pull request 'feat: Remove ELRS arm requirement (Issue #512)' (#514) from sl-firmware/issue-512-autonomous-arming into main

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Reference: seb/saltylab-firmware#514