micro-ROS
可行性分析
micro-ROS框架
micro-ROS静态库编译
1. 下载micro_ros_setup
2. 下载micro-ROS相关代码
3. 创建交叉编译链
4. 创建和编译静态库相关的宏定义
5 编译
micro-ROS静态库移植
1. 复制静态库和头文件
2. 将库和头文件包含进工程
3. 添加接口函数
4. 添加时钟同步函数
测试
publish测试
subscriber测试
总结
下一步
参考
相关代码和《Robot Operating System》,回复"microROS"
micro-ROS
可行性分析
micr-ROS是ROS2专门为微控制器开发的组件，旨在将微控制器变成ROS2的一个节点连接进入ROS系统中。在实际应用中，我们可以实现将微控制器直接接入ROS系统，而不是首先微控制器和树莓派等控制器通信，然后树莓派接入ROS系统。
micr-ROS主要针对中高端的32位单片机，其占用内存根据节点数量和消息类型变化而变化，一般来说，micro-ROS 需要数十 KB 的RAM ，其支持主要硬件如下：
| 板卡 | MCU | RAM | flah |
|---|---|---|---|
| Espressif ESP32 | ultra-low power dual-core Xtensa LX6 | 520 kB | 4 MB |
| Raspberry Pi Pico RP2040 | Dual-core Arm Cortex-M0+ | 264 kB | 16 MB |
| ROBOTIS OpenCR 1.0 | ARM Cortex-M7 STM32F746ZGT6 | 320 kB | 1024 kB |
| Teensy 3.2 | ARM Cortex-M4 MK20DX256VLH7 | 64 kB | 256 kB |
| STM32L4 Discovery kit IoT | ARM Cortex-M4 STM32L4 | 128 kB | 1MB |
详细支持硬件详见链接1
支持平台
- FreeRTOS;
- ThreadX;
- Arduino;
- Zephyr;
- ...
其更详细的支持平台，见micr-ROS仓库[2]
XR806的CPU为Arm-Star ARMv8-M，288KB SRAM，160KB Code ROM. 和16Mbit Flash。从内存上来说，满足要求。另外本次测评的是XR806 FreeRTOS 的SDK，也属于miro-ROS的支持平台，加大将miro-ROS移植到XR806中的可能性。
对于外设，一般都使用uart和UDP。XR806也满足要求。
综上，将miro-ROS移植到XR806中，具有可行性；
micro-ROS框架
img从框架可以看出，FreeRTOS系统是很容易接入micro-ROS，关于micro-ROS框架的详细描述，请参考官网或Robot Operating System (ROS)这本书籍的的第七章。
micro-ROS静态库编译
XR806不在micro-ROS支持的硬件中，因此没有可直接使用的静态库，但是其官网提供将micro-ROS编译成静态库[3]的方法。
前提要求：
- 在PC上安装好ROS2，其安装参考官网[4]，版本：galactic（其他版本也是可以）
也可以使用docker，本次未使用，不做介绍。
1. 下载micro_ros_setup
micro-ROS相关操作被封装到micro_ros_setup节点中
# 启动ROS2 环境
source /opt/ros/galactic/setup.sh
# 创建工作空间用于下载micro-ROS tools
mkdir microros_ws
cd microros_ws
git clone -b galactic https://github.com/micro-ROS/micro_ros_setup.git src/micro_ros_setup
# 更新依赖
sudo apt update && rosdep update
rosdep install --from-paths src --ignore-src -y
# 编译
colcon build
# source 工作空间
source install/local_setup.bash
2. 下载micro-ROS相关代码
ros2 run micro_ros_setup create_firmware_ws.sh generate_lib
该命令将从github拉取众多程序，保证网络流程，必要时挂梯子才能保证代码拉取成功。若没有梯子，可以在公众号中回复“clash”获取我目前使用的梯子。拉去的时间比较长，耐心等待。
拉取的文件放在firmware文件中，具体内容如下
.
├── COLCON_IGNORE
├── dev_ws
│ ├── ament
│ ├── build
│ ├── install
│ ├── log
│ ├── ros2
│ └── ros2.repos
├── mcu_ws
│ ├── colcon.meta
│ ├── eProsima
│ ├── ros2
│ ├── ros2.repos
│ └── uros
└── PLATFORM
3. 创建交叉编译链
touch toolchain.cmake
内容如下：
set(CMAKE_SYSTEM_NAME Generic)
set(CMAKE_CROSSCOMPILING 1)
set(CMAKE_TRY_COMPILE_TARGET_TYPE STATIC_LIBRARY)
# SET HERE THE PATH TO YOUR C99 AND C++ COMPILERS
set(CMAKE_C_COMPILER "/home/haijun/xr806/tools/gcc-arm-none-eabi-8-2019-q3-update/bin/arm-none-eabi-gcc")
set(CMAKE_CXX_COMPILER "/home/haijun/xr806/tools/gcc-arm-none-eabi-8-2019-q3-update/bin/arm-none-eabi-g++")
set(CMAKE_C_COMPILER_WORKS 1 CACHE INTERNAL "")
set(CMAKE_CXX_COMPILER_WORKS 1 CACHE INTERNAL "")
# SET HERE YOUR BUILDING FLAGS
set(FLAGS "-O2 -mcpu=cortex-m33 -mtune=cortex-m33 -march=armv8-m.main+dsp -mfpu=fpv5-sp-d16 -mfloat-abi=softfp -mcmse -mthumb --param max-inline-insns-single=500 -DF_CPU=84000000L -D'RCUTILS_LOG_MIN_SEVERITY=RCUTILS_LOG_MIN_SEVERITY_NONE'" CACHE STRING "" FORCE)
set(CMAKE_C_FLAGS_INIT "-std=gnu99 ${FLAGS} -DCLOCK_MONOTONIC=0 -D'__attribute__(x)='" CACHE STRING "" FORCE)
set(CMAKE_CXX_FLAGS_INIT "-std=gnu++98 ${FLAGS} -fno-rtti -DCLOCK_MONOTONIC=0 -D'__attribute__(x)='" CACHE STRING "" FORCE)
set(__BIG_ENDIAN__ 0)
CMAKE_C_COMPILER和CMAKE_CXX_COMPILER为交叉编译链的路径；FLAGS设置和芯片相关的宏编译指令，来自于SDK中gcc.mk中的设置内容；
4. 创建和编译静态库相关的宏定义
touch colcon.meta
{
"names": {
"tracetools": {
"cmake-args": [
"-DTRACETOOLS_DISABLED=ON",
"-DTRACETOOLS_STATUS_CHECKING_TOOL=OFF"
]
},
"rosidl_typesupport": {
"cmake-args": [
"-DROSIDL_TYPESUPPORT_SINGLE_TYPESUPPORT=ON"
]
},
"rcl": {
"cmake-args": [
"-DBUILD_TESTING=OFF",
"-DRCL_COMMAND_LINE_ENABLED=OFF",
"-DRCL_LOGGING_ENABLED=OFF"
]
},
"rcutils": {
"cmake-args": [
"-DENABLE_TESTING=OFF",
"-DRCUTILS_NO_FILESYSTEM=ON",
"-DRCUTILS_NO_THREAD_SUPPORT=ON",
"-DRCUTILS_NO_64_ATOMIC=ON",
"-DRCUTILS_AVOID_DYNAMIC_ALLOCATION=ON"
]
},
"microxrcedds_client": {
"cmake-args": [
"-DUCLIENT_PIC=OFF",
"-DUCLIENT_PROFILE_UDP=OFF",
"-DUCLIENT_PROFILE_TCP=OFF",
"-DUCLIENT_PROFILE_DISCOVERY=OFF",
"-DUCLIENT_PROFILE_SERIAL=OFF",
"-UCLIENT_PROFILE_STREAM_FRAMING=ON",
"-DUCLIENT_PROFILE_CUSTOM_TRANSPORT=ON"
]
},
"rmw_microxrcedds": {
"cmake-args": [
"-DRMW_UXRCE_MAX_NODES=1",
"-DRMW_UXRCE_MAX_PUBLISHERS=5",
"-DRMW_UXRCE_MAX_SUBSCRIPTIONS=5",
"-DRMW_UXRCE_MAX_SERVICES=1",
"-DRMW_UXRCE_MAX_CLIENTS=1",
"-DRMW_UXRCE_MAX_HISTORY=4",
"-DRMW_UXRCE_TRANSPORT=custom"
]
}
}
}
该文件规定哪些文件会被编译，定义了该静态库许可允许的最大节点数为1，最大发布量为5，最大订阅量为5，最大服务数为1，。可以根据微控制器的内存调整。
5 编译
ros2 run micro_ros_setup build_firmware.sh $(pwd)/toolchain.cmake $(pwd)/colcon.meta
编译成功标志：64个包被编译
Summary: 64 packages finished [2min 0s]
40 packages had stderr output: action_msgs actionlib_msgs builtin_interfaces composition_interfaces diagnostic_msgs example_interfaces geometry_msgs libyaml_vendor lifecycle_msgs micro_ros_msgs micro_ros_utilities microxrcedds_client nav_msgs rcl rcl_action rcl_interfaces rcl_lifecycle rcl_logging_interface rcl_logging_noop rclc rclc_lifecycle rclc_parameter rcutils rmw rmw_implementation rmw_microxrcedds rosgraph_msgs rosidl_runtime_c rosidl_typesupport_c rosidl_typesupport_microxrcedds_c sensor_msgs shape_msgs statistics_msgs std_msgs std_srvs stereo_msgs test_msgs trajectory_msgs unique_identifier_msgs visualization_msgs
并在firmware/build生成静态库libmicroros.a和相应的头文件include
haijun@haijun-Lenovo:~/Desktop/microros_ws/firmware/build$ tree -L 2
.
├── include # 相关头文件
│ ├── actionlib_msgs
│ ├── action_msgs
│ ├── builtin_interfaces
│ ├── composition_interfaces
│ ├── diagnostic_msgs
│ ├── example_interfaces
│ ├── geometry_msgs
│ ├── lifecycle_msgs
│ ├── micro_ros_msgs
│ ├── micro_ros_utilities
│ ├── nav_msgs
│ ├── rcl
│ ├── rcl_action
│ ├── rclc
│ ├── rclc_lifecycle
│ ├── rclc_parameter
│ ├── rcl_interfaces
│ ├── rcl_lifecycle
│ ├── rcl_logging_interface
│ ├── rcutils
│ ├── rmw
│ ├── rmw_microros
│ ├── rmw_microxrcedds_c
│ ├── rosgraph_msgs
│ ├── rosidl_runtime_c
│ ├── rosidl_typesupport_c
│ ├── rosidl_typesupport_interface
│ ├── rosidl_typesupport_introspection_c
│ ├── rosidl_typesupport_microxrcedds_c
│ ├── sensor_msgs
│ ├── shape_msgs
│ ├── statistics_msgs
│ ├── std_msgs
│ ├── std_srvs
│ ├── stereo_msgs
│ ├── test_msgs
│ ├── tracetools
│ ├── trajectory_msgs
│ ├── ucdr
│ ├── unique_identifier_msgs
│ ├── uxr
│ ├── visualization_msgs
│ └── yaml.h
└── libmicroros.a
├── include
│ ├── actionlib_msgs
│ ├── action_msgs
│ ├── builtin_interfaces
│ ├── composition_interfaces
│ ├── diagnostic_msgs
│ ├── example_interfaces
│ ├── geometry_msgs
│ ├── lifecycle_msgs
│ ├── micro_ros_msgs
│ ├── micro_ros_utilities
│ ├── nav_msgs
│ ├── rcl
│ ├── rcl_action
│ ├── rclc
│ ├── rclc_lifecycle
│ ├── rclc_parameter
│ ├── rcl_interfaces
│ ├── rcl_lifecycle
│ ├── rcl_logging_interface
│ ├── rcutils
│ ├── rmw
│ ├── rmw_microros
│ ├── rmw_microxrcedds_c
│ ├── rosgraph_msgs
│ ├── rosidl_runtime_c
│ ├── rosidl_typesupport_c
│ ├── rosidl_typesupport_interface
│ ├── rosidl_typesupport_introspection_c
│ ├── rosidl_typesupport_microxrcedds_c
│ ├── sensor_msgs
│ ├── shape_msgs
│ ├── statistics_msgs
│ ├── std_msgs
│ ├── std_srvs
│ ├── stereo_msgs
│ ├── test_msgs
│ ├── tracetools
│ ├── trajectory_msgs
│ ├── ucdr
│ ├── unique_identifier_msgs
│ ├── uxr
│ ├── visualization_msgs
│ └── yaml.h
└── libmicroros.a # 静态库
到此，静态库的编译工作完成。
micro-ROS静态库移植
1. 复制静态库和头文件
使用工程：xr806_sdk/project/demo/ros2
# 创建microros来存静态文件库和头文件
mkdir -p project/demo/ros2/microros/
# 复制
cp -rf ~/Desktop/microros_ws/firmware/build/ project/demo/ros2/microros/
2. 将库和头文件包含进工程
修改project/demo/ros2/gcc/Makefile
...
DIRS_IGNORE += $(ROOT_PATH)/project/common/board/$(shell echo $(CONFIG_BOARD))
# 忽视文件夹中的内容：不参与编译
DIRS_IGNORE += $(PRJ_ROOT_PATH)/microros%
...
# extra libraries searching path
PRJ_EXTRA_LIBS_PATH := -L$(PRJ_ROOT_PATH)/microros
# extra libraries
PRJ_EXTRA_LIBS := -lmicroros
# extra header files searching path
PRJ_EXTRA_INC_PATH := -I$(PRJ_ROOT_PATH)/microros/include
...
其中DIRS_IGNORE += $(PRJ_ROOT_PATH)/microros%很重要，不加，按照已有的编译规则，microros文件下的内容也会参与编译，因缺少相关c文件编译失败。
3. 添加接口函数
micro-ROS和PC上的ROS服务端通信需要实现rmw_uros_set_custom_transportAPI 中的内容[6]：
rmw_uros_set_custom_transport(
true, // Framing enabled here. Using Stream-oriented mode.
(void *) &args,
my_custom_transport_open,
my_custom_transport_close,
my_custom_transport_write,
my_custom_transport_read
);
从定义来说，则是实现uart的初始化，读、写三个功能
创建set_microros_transports()函数用于调用rmw_uros_set_custom_transport()
static inline void set_microros_transports()
{
rmw_uros_set_custom_transport(
1,
(void *) NULL,
serial_transport_open,
serial_transport_close,
serial_transport_write,
serial_transport_read
);
}
实现uart接口函数
/*串口1初始化*/
static int uart_init(void)
{
UART_InitParam param;
param.baudRate = 115200;
param.dataBits = UART_DATA_BITS_8;
param.stopBits = UART_STOP_BITS_1;
param.parity = UART_PARITY_NONE;
param.isAutoHwFlowCtrl = 0;
if(HAL_UART_Init(UARTID, ¶m) != HAL_OK)
return -1;
/*使能DMA*/
if (HAL_UART_EnableTxDMA(UARTID) != HAL_OK)
return -2;
if (HAL_UART_EnableRxDMA(UARTID) != HAL_OK)
return -3;
return 0;
}
bool serial_transport_open(uxrCustomTransport* transport){
HAL_Status status = HAL_ERROR;
status = uart_init();
if(status == HAL_OK){
printf("open uart%d successful!\n", UARTID);
return 1;
}
else{
printf("open uart%d fail!\n", UARTID);
return 0;
}
}
bool serial_transport_close(uxrCustomTransport* transport){
HAL_Status status = HAL_ERROR;
HAL_UART_DisableTxDMA(UARTID);
HAL_UART_DisableRxDMA(UARTID);
status = HAL_UART_DeInit(UARTID);
if(status == HAL_OK)
return 1;
else
return 0;
}
size_t serial_transport_write(uxrCustomTransport* transport,const uint8_t* buffer,
size_t length,uint8_t* errcode){
return HAL_UART_Transmit_DMA(UARTID, (uint8_t *)buffer, length);
}
size_t serial_transport_read(uxrCustomTransport* transport,uint8_t* buffer,
size_t length,int timeout,uint8_t* errcode){
return HAL_UART_Receive_DMA(UARTID, buffer, length, timeout);
}
#endif
4. 添加时钟同步函数
micro-ROS还需要一个时钟函数，以保证微控制器和ROS2同步
#define micro_rollover_useconds 4294967295
int clock_gettime(clockid_t unused, struct timespec *tp)
{
(void)unused;
static uint32_t rollover = 0;
static uint32_t last_measure = 0;
uint32_t m = OS_GetTicks() * 1000;
rollover += (m < last_measure) ? 1 : 0;
uint64_t real_us = (uint64_t) (m + rollover * micro_rollover_useconds);
tp->tv_sec = real_us / 1000000;
tp->tv_nsec = (real_us % 1000000) * 1000;
last_measure = m;
return 0;
}
时间计算主要通过滴答函数OS_GetTicks()获取。
到此，完成micro-ROS的移植！
测试
publish测试
XR806发布一个int32位的数字，在ROS2上检验是否发布有相应的节点，话题，是否查询到话题的消息。
XR806端
XR806端publish代码：
static void timer_callback(rcl_timer_t * timer, int64_t last_call_time)
{
if (timer != NULL)
{
RCSOFTCHECK(rcl_publish(&publisher, &msg, NULL));
msg.data++;
printf("msg.data = %d\n", msg.data);
}
else {
printf("micrros timer null\n");
}
}
void microros_pub_int32()
{
OS_MSleep(100);
RCCHECK(rclc_executor_spin_some(&executor, RCL_MS_TO_NS(100)));
}
void microros_pub_int32_init()
{
#if defined MICROROS_SERIAL
set_microros_transports();
#endif
allocator = rcl_get_default_allocator();
//create init_options
RCCHECK(rclc_support_init(&support, 0, NULL, &allocator));
// create node
RCCHECK(rclc_node_init_default(&node, "xr806_node", "", &support));
// create publisher
RCCHECK(rclc_publisher_init_default(
&publisher,
&node,
ROSIDL_GET_MSG_TYPE_SUPPORT(std_msgs, msg, Int32),
"xr806_node_publisher")
);
// create timer
const unsigned int timer_timeout = 1000;
RCCHECK(rclc_timer_init_default(
&timer,
&support,
RCL_MS_TO_NS(timer_timeout),
timer_callback)
);
// create executor
RCCHECK(rclc_executor_init(&executor, &support.context, 1, &allocator));
RCCHECK(rclc_executor_add_timer(&executor, &timer));
msg.data = 0;
printf("micro_ros init successful.\n");
}
设置节点：xr806_node；话题xr806_node_publisher，消息类型：std_msgs.msg.Int32。并定义了一个1000ms的定时器，用于msg.data++。
在主函数中初始化microros_pub_int32_init();,循环调用microros_pub_int32();
PC端
创建micro-ROS agent
source /opt/ros/galactic/setup.sh
ros2 run micro_ros_setup create_agent_ws.sh
ros2 run micro_ros_setup build_agent.sh
source install/local_setup.sh
在PC端运行agent
ros2 run micro_ros_agent micro_ros_agent serial -D /dev/ttyUSB1 -v6
启动XR806，结果如下
subscriber测试
XR806端
初始化
void microros_sub_int32_init()
{
#if defined MICROROS_SERIAL
set_microros_transports();
#endif
allocator = rcl_get_default_allocator();
// create init_options
RCCHECK(rclc_support_init(&support, 0, NULL, &allocator));
// create node
RCCHECK(rclc_node_init_default(&node, "xr806_node", "", &support));
// create subscriber
RCCHECK(rclc_subscription_init_default(
&subscriber,
&node,
ROSIDL_GET_MSG_TYPE_SUPPORT(std_msgs, msg, Int32),
"xr806_node_subscriber"));
// create executor
RCCHECK(rclc_executor_init(&executor, &support.context, 1, &allocator));
RCCHECK(rclc_executor_add_subscription(&executor, &subscriber, &recv_msg, &subscription_callback, ON_NEW_DATA));
printf("micro_ros init successful.\n");
// ros2 topic pub /micro_ros_xr806_node_subscriber std_msgs/msg/Int32 data:\ 12
}
- 节点：xr806_node
- 话题：xr806_node_subscriber
回调函数
static void subscription_callback(const void * msgin)
{
count ++;
const std_msgs__msg__Int32 * msg = (const std_msgs__msg__Int32 *)msgin;
printf("%d: Received: %d\n", count, msg->data);
}
回调函数打印订阅的次数和消息内容。
PC端
ros2 run micro_ros_agent micro_ros_agent serial -D /dev/ttyUSB1 -v6,ros2 topic pub /micro_ros_xr806_node_subscriber std_msgs/msg/Int32 data:\ XX效果：
下一步
参考
[1] https://micro.ros.org/docs/overview/hardware/
[2] https://github.com/micro-ROS
[3] https://micro.ros.org/docs/tutorials/advanced/create_custom_static_library/
[4] https://docs.ros.org/en/foxy/Installation.html
[6] https://micro.ros.org/docs/tutorials/advanced/create_custom_transports/