sl-jetson 30be0d8cd3 feat(bridge): binary STM32 command protocol (Issue #119)
Add stm32_protocol.py — pure-Python binary frame codec:
- Frame: STX(0x02)+TYPE+LEN+PAYLOAD+CRC16-CCITT(BE)+ETX(0x03)
- CRC covers TYPE+LEN+PAYLOAD; polynomial 0x1021, init 0xFFFF
- Encoders: HEARTBEAT, SPEED_STEER(-1000..+1000 int16), ARM, SET_MODE, PID_UPDATE
- Telemetry decoders: ImuFrame, BatteryFrame, MotorRpmFrame, ArmStateFrame, ErrorFrame
- FrameParser: streaming byte-by-byte state machine, resync on corrupt data

Add stm32_cmd_node.py — ROS2 bidirectional bridge node:
- /cmd_vel → SPEED_STEER at up to 50 Hz
- HEARTBEAT timer (default 200ms); STM32 watchdog fires at 500ms
- Jetson-side watchdog: no /cmd_vel for 500ms → send SPEED_STEER(0,0)
- /saltybot/arm service (SetBool) → ARM frame
- /saltybot/pid_update topic → PID_UPDATE frame
- Telemetry RX: IMU→/saltybot/imu, BATTERY→/saltybot/telemetry/battery,
  MOTOR_RPM→/saltybot/telemetry/motor_rpm, ARM_STATE→/saltybot/arm_state,
  ERROR→/saltybot/error
- Auto-reconnect on USB disconnect (serial.SerialException caught)
- Zero-speed + disarm sent on node shutdown
- /diagnostics with serial health, frame counts, last cmd age

Add test_stm32_protocol.py (60+ tests):
- CRC16-CCITT correctness, known test vectors
- All encoder output structures and payload values
- FrameParser: all telemetry types, bad CRC, bad ETX, resync, streaming,
  oversized payload, frame counters, reset

Add test_stm32_cmd_node.py (30+ tests):
- MockSerial: TX/RX byte-level testing without hardware
- Speed/steer clamping, scaling, frame structure
- Watchdog fires/doesn't fire relative to timeout
- CRC error counted, resync after garbage

Add stm32_cmd_params.yaml, stm32_cmd.launch.py.
Update package.xml (add std_srvs, geometry_msgs deps).
Update setup.py (add stm32_cmd_node entry point + new config/launch).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
2026-03-02 09:17:04 -05:00

53 lines
2.1 KiB
Python

"""stm32_cmd.launch.py — Launch the binary-framed STM32 command node (Issue #119).
Usage:
# Default (binary protocol, bidirectional):
ros2 launch saltybot_bridge stm32_cmd.launch.py
# Override serial port:
ros2 launch saltybot_bridge stm32_cmd.launch.py serial_port:=/dev/ttyACM1
# Custom velocity scales:
ros2 launch saltybot_bridge stm32_cmd.launch.py speed_scale:=800.0 steer_scale:=-400.0
"""
import os
from ament_index_python.packages import get_package_share_directory
from launch import LaunchDescription
from launch.actions import DeclareLaunchArgument
from launch.substitutions import LaunchConfiguration
from launch_ros.actions import Node
def generate_launch_description() -> LaunchDescription:
pkg = get_package_share_directory("saltybot_bridge")
params_file = os.path.join(pkg, "config", "stm32_cmd_params.yaml")
return LaunchDescription([
DeclareLaunchArgument("serial_port", default_value="/dev/ttyACM0"),
DeclareLaunchArgument("baud_rate", default_value="921600"),
DeclareLaunchArgument("speed_scale", default_value="1000.0"),
DeclareLaunchArgument("steer_scale", default_value="-500.0"),
DeclareLaunchArgument("watchdog_timeout", default_value="0.5"),
DeclareLaunchArgument("heartbeat_period", default_value="0.2"),
Node(
package="saltybot_bridge",
executable="stm32_cmd_node",
name="stm32_cmd_node",
output="screen",
emulate_tty=True,
parameters=[
params_file,
{
"serial_port": LaunchConfiguration("serial_port"),
"baud_rate": LaunchConfiguration("baud_rate"),
"speed_scale": LaunchConfiguration("speed_scale"),
"steer_scale": LaunchConfiguration("steer_scale"),
"watchdog_timeout": LaunchConfiguration("watchdog_timeout"),
"heartbeat_period": LaunchConfiguration("heartbeat_period"),
},
],
),
])