microAutoware: An Autoware vehicle interface for real-time embedded systems

microAutoware is a package based in micro-ROS to bring the Autoware Core/Universe inside a microcontroller with Hardware-In-the-Loop (HIL) validation support.

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Introduction

Looking to bring standardization to the Autoware Core/Universe interface with the vehicle's low-level modules, microAutoware utilizes micro-ROS to embed the vehicle interface module inside the microcontroller, using the default ROS2 topics and services to control the vehicle. Another advantage of this package is its independence from the physical layer, where data between Autoware and microAutoware can be transmitted through UART (as validated in this repository), Ethernet, or other micro-ROS-compatible protocols.

As of now, microAutoware is available only for STM32 microcontrollers using FreeRTOS, but there are future plans to expand compatibility to other hardware families and RTOSes.

In FreeRTOS, microAutoware is implemented as a task that communicates and synchronizes with other tasks using event flags and global variables protected by a mutex.

Dependencies

• ROS 2 Humble
• Autoware Core/Universe 2024.01
• STM32 microcontroller that supports micro-ROS
• For HIL testbed:
  • CARLA Simulator 0.9.15

microAutoware lib

• microAutoware.h
  • Header file including: micro-ROS libraries, Autoware libraries, defining flags, declaring structs typedefs and function prototypes.
• microAutoware.c
  • microAutoware task, that implement the micro-ROS node and declare package's global variables.
• microAutoware_config.h
  • Header file to configure microAutoware parameters, as timeouts, timing, transport layer and node name.
• executorCallbacks.c
  • Declaration of micro-ROS callback functions for timers, topics and services.

Creating project in STM32CubeIDE

STM32CubeIDE 1.15.1

1. After create your project in STM32CubeIDE, the first step is configure the code generation:

   • In your .ioc file go to: Project Manager > Code Generator;
   • Check Generate peripheral initialization as a pair of 'c/.h' files per peripheral.

2. Once you configured the FreeRTOS using CMSIS_V2, is necessary to create the microAutoware tasks and RTOS entities:

   • Again in the .ioc file, go to: Pinout & Configuration > Middleware and Software > FREERTOS > Configuration > Tasks and Queues;

     • Create microAutoware task as below:

       Field	Parameter
       Task Name	TaskMicroAutowa
       Priority	osPriorityNormal
       Stack Size (Words)	4500
       Entry Function	StartMicroAutoware
       Code Generation Option	As external
       Parameter	NULL
       Allocation	Dynamic
       Buffer Name	NULL
       Control Block Name	NULL

       It's important that microAutoware task don't stay blocked for long once the executor runs periodically. Thus, is important to evaluate TaskMicroAutowa priority to avoid starvation.

   • Now, the mutexes are created in Pinout & Configuration > Middleware and Software > FREERTOS > Configuration > Mutexes;

     • Create microAutoware mutexes as below:

       1. MutexVehicleStatus

          Field	Parameter
          Mutex Name	MutexVehicleStatus
          Allocation	Dynamic
          Control Block Name	NULL

       2. MutexControlAction

          Field	Parameter
          Mutex Name	MutexControlAction
          Allocation	Dynamic
          Control Block Name	NULL

   • Finally, is necessary to create the event flag object, going to Pinout & Configuration > Middleware and Software > FREERTOS > Configuration > Events;

     • Create microAutoware event flags as below:

       Field	Parameter
       Event flags Name	EventsMicroAutoware
       Allocation	Dynamic
       Control Block Name	NULL

3. Copy microAutoware_config.h and microAutoware.h to Core/Inc project folder;

4. Copy microAutoware.c and executorCallbacks.c to Core/Src project folder;

5. Clone micro-ROS for microAutoware repository:

git clone -b humble [email protected]:LMA-FEM-UNICAMP/microautoware_micro-ROS_stm32.git

6. Configure micro-ROS for microAutoware [1]: microautoware_micro-ROS_stm32 project configuration.

Global variables

xVehicleStatus

• Collect vehicle information to publish in Autoware.

• Type: vehicle_status

  Variable	Type	Description
  xLongSpeed	float	Longitudinal speed (m/s)
  xLatSpeed	float	Lateral speed (m/s)
  xHeadingRate	float	Heading rate (rad/s)
  xSteeringStatus	float	Steering tire angle (rad)

xControlAction

• Compact Autoware's high-level control references to embedded system low-level control tasks.

• Type: control_action

  Variable	Type	Description
  xSteeringAngle	float	Steering tire angle (rad)
  xSteeringVelocity	float	Steering tire speed (rad/s)
  xSpeed	float	Speed (m/s)
  xAcceleration	float	Acceleration (m/s^2 )
  xJerk	float	Jerk (m/s^3)
  ucControlMode	unsigned char	Vehicle control mode (HIL only)

Flags

VEHICLE_DATA_UPDATED_FLAG

Once the vehicle information to the Autoware are ready, the VEHICLE_DATA_UPDATED_FLAG is set to microAutoware and sends that data through ROS.

• Pooling flag to microAutoware task.

AUTOWARE_DATA_UPDATED_FLAG

When microAutoware receives Autoware's data and updates xControlAction, the AUTOWARE_DATA_UPDATED_FLAG is set to system tasks to process that information.

• Blocks control task.

Change control mode flags

A command to change the vehicle's control mode can be executed from either Autoware or the vehicle, i.e., there is a two-way control mode change. Therefore, the flags to activate the mode change were split into two flags for each function, with the prefix MA_ when the command comes from the vehicle and SYS_ when it comes from Autoware.

Both the TO_AUTOWARE_MODE, TO_MANUAL_MODE, and EMERGENCY_MODE flags are non-blocking and are polled at the start of the execution of the microAutoware task, as well as in the system task designed in the HIL package. The last two flags are used for fail-safe capabilities, and the last one is used exclusively for this purpose.

MICRO_ROS_AGENT_ONLINE_FLAG

When the embedded system is powered on, microAutoware tries to connect to the micro-ROS agent to establish communication with Autoware, and the system task loops are blocked. When this occurs, the MICRO_ROS_AGENT_ONLINE_FLAG flag is set, unblocking the system tasks. This flag has a timeout, and if the high-level system does not connect to the low-level system, the embedded system powers up in manual mode only.

HIL Mode

Embedded system configuration

1. To use the HIL testbed, is needed to configure the TaskControle task, as follow:

   • In the .ioc file, go to: Pinout & Configuration > Middleware and Software > FREERTOS > Configuration > Tasks and Queues;

     • Create TaskControle task as below:

       Field	Parameter
       Task Name	TaskControl
       Priority	osPriorityAboveNormal
       Stack Size (Words)	1500
       Entry Function	StartTaskControl
       Code Generation Option	As weak
       Parameter	NULL
       Allocation	Dynamic
       Buffer Name	NULL
       Control Block Name	NULL

2. Finally, set the USE_SIM_TIME constant in microAutoware_config.h to true.

Autoware + CARLA configuration

The HIL testbed uses the Carla-Autoware-Bridge, forked from [2] to work within microAutoware. Is necessary to follow the instructions of the repository.

microAutoware + CARLA configuration

To communicate the embedded system with the CARLA Simulator, the serial-ROS package carla_serial_bridge is used, but another strategies could be explored if it's of interest. micro-ROS aren't employed to this function to avoid overheading of the framework with the simulated vehicle data that in real world don't flow through then.

Running HIL testbed

1. Launch CARLA Simulator

./CarlaUE4.sh -carla-rpc-port=1403

2. Launch Carla-Autoware-Bridge

ros2 launch carla_autoware_bridge carla_aw_bridge.launch.py port:=1403 town:=Town10HD timeout:=100

3. Launch carla_serial_bridge

ros2 run carla_serial_bridge carla_serial_bridge_node

4. Launch micro-ROS agent

ros2 run micro_ros_agent micro_ros_agent serial --dev /dev/ttyACM0 -b 921600

5. Launch Autoware Core/Universe

ros2 launch autoware_launch e2e_simulator.launch.xml vehicle_model:=carla_t2_vehicle sensor_model:=carla_t2_sensor_kit map_path:=/home/vilma/autoware_ws/maps/carla-autoware-bridge/Town10

6. Set third view camera in CARLA Simulator (optional)

python src/Carla-Autoware-Bridge/utils/thirdview_camera.py

1, 2, 3 and 4 could be compacted in a single launch file

References

[1] micro-ROS for STM32CubeMX/IDE. Available in: github.com/micro-ROS/micro_ros_stm32cubemx_utils.

[2] G. Kaljavesi, T. Kerbl, T. Betz, K. Mitkovskii and F. Diermeyer, "CARLA-Autoware-Bridge: Facilitating Autonomous Driving Research with a Unified Framework for Simulation and Module Development," 2024 IEEE Intelligent Vehicles Symposium (IV), Jeju Island, Korea, Republic of, 2024, pp. 224-229, doi: 10.1109/IV55156.2024.10588623. Available in: github.com/TUMFTM/Carla-Autoware-Bridge.