feat: person-following control loop (Phase 2b)
Adds saltybot_follower ROS2 package — proportional person-following
controller that bridges sl-jetson's /person/target detections to Nav2
/cmd_vel, with the cmd_vel_bridge_node (PR #46) providing safety wrapping.
Controller features:
- Proportional control: linear.x ∝ distance error, angular.z ∝ bearing
- Follow distance: 1.5m default with ±0.3m dead zone (no jitter at target)
- Max speed: 0.5 m/s linear, 1.0 rad/s angular (conservative for balance)
- Obstacle override: zeroes forward cmd_vel when Nav2 local costmap
detects obstacle in forward corridor; turning still allowed
- Lost-target state machine:
FOLLOWING → person visible
STOPPING → lost > 2s, publish zero
SEARCHING → lost > 5s, slow rotation (0.3 rad/s) to re-acquire
- Mode integration: follow_enabled param (toggle via ros2 param set)
independently gates the controller; cmd_vel bridge gates on md=2
Deliverables:
saltybot_follower/person_follower_node.py — ROS2 node (314 lines)
config/person_follower_params.yaml — all params documented
launch/person_follower.launch.py — all params as launch args
test/test_person_follower.py — 53 pytest tests, no ROS2
package.xml / setup.py / setup.cfg — package metadata
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
sl-controls
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