Px4 Ros2

PX4 ROS2 集成技能

用于将 PX4 与 ROS2 系统集成实现自主控制

何时使用

当需要以下帮助时使用此技能：

• 配置 MAVROS/mavros2
• 通过 ROS2 控制无人机
• 订阅 PX4 话题
• 实现 Offboard 模式控制

快速参考

安装 MAVROS

# ROS2 安装
sudo apt install ros-${ROS_DISTRO}-mavros ros-${ROS_DISTRO}-mavros-extras

# 安装 mavros 工具
sudo apt install mavros-utils

启动 MAVROS

# 通过 UDP 连接 SITL
ros2 launch mavros px4.launch fcu_url:="udp://:14540@"

# 通过 UDP 连接真实飞控
ros2 launch mavros px4.launch fcu_url:="udp://192.168.1.1:14550@"

# 通过串口连接
ros2 launch mavros px4.launch fcu_url:="/dev/ttyUSB0:921600"

MAVROS 节点

话题订阅

话题发布

Offboard 控制示例

节点模板 (Python)

#!/usr/bin/env python3
import rclpy
from rclpy.node import Node
from geometry_msgs.msg import PoseStamped
from mavros_msgs.srv import CommandBool, SetMode
from mavros_msgs.msg import State

class OffboardNode(Node):
    def __init__(self):
        super().__init__('offboard_node')
        
        # 状态订阅
        self.state_sub = self.create_subscription(
            State,
            '/mavros/state',
            self.state_callback)
        
        # 位置发布
        self.pos_pub = self.create_publisher(
            PoseStamped,
            '/mavros/setpoint_position/local',
            10)
        
        # 服务客户端
        self.arm_client = self.create_client(CommandBool, '/mavros/cmd/arming')
        self.mode_client = self.create_client(SetMode, '/mavros/set_mode')
        
        self.connected = False
        self.armed = False
        
    def state_callback(self, msg):
        self.connected = msg.connected
        self.armed = msg.armed
        
    def send_position(self, x, y, z):
        pose = PoseStamped()
        pose.header.stamp = self.get_clock().now().to_msg()
        pose.pose.position.x = x
        pose.pose.position.y = y
        pose.pose.position.z = z
        self.pos_pub.publish(pose)

起飞降落

起飞命令

# 通过 service
ros2 service call /mavros/cmd/takeoff mavros_msgs/srv/CommandTOL \
  "{min_pitch: 0.0, yaw: 0.0, latitude: 0.0, longitude: 0.0, altitude: 2.0}"

降落命令

ros2 service call /mavros/cmd/land mavros_msgs/srv/CommandTOL \
  "{min_pitch: 0.0, yaw: 0.0, latitude: 0.0, longitude: 0.0, altitude: 0.0}"

解锁/锁定

# 解锁
ros2 service call /mavros/cmd/arming mavros_msgs/srv/CommandBool \
  "{value: true}"

# 锁定
ros2 service call /mavros/cmd/arming mavros_msgs/srv/CommandBool \
  "{value: false}"

切换飞行模式

# Offboard 模式
ros2 service call /mavros/set_mode mavros_msgs/srv/SetMode \
  "{custom_mode: 'OFFBOARD'}"

# Position 模式
ros2 service call /mavros/set_mode mavros_msgs/srv/SetMode \
  "{custom_mode: 'POSCTL'}"

# Stabilized 模式
ros2 service call /mavros/set_mode mavros_msgs/srv/SetMode \
  "{custom_mode: 'STABILIZED'}"

速度控制

速度消息

ros2 topic pub /mavros/setpoint_velocity/cmd_vel geometry_msgs/Twist \
  "{linear: {x: 1.0, y: 0.0, z: 0.0}, angular: {x: 0.0, y: 0.0, z: 0.0}}"

参数配置

mavros 参数文件

mavros:
  fcu_url: "udp://:14540@"
  fcu_protocol: "v2.0"
  protocol_version: "2.0"
  
  pub_global_position: {frame_id: "map", rate: 100.0}
  pub_local_position: {frame_id: "base_link", rate: 50.0}
  pub_imu: {frame_id: "base_link", rate: 100.0}
  
  subscribe_attitude: true
  subscribe_rc: true

使用 XRCE-DDS

PX4 端配置

# 启用 uXRCE-DDS
UXRCE_DDS_CFG = 1  # 启用
UXRCE_DDS_PRT      # 端口

ROS 2 端

# 安装 micro_ros_agent
sudo apt install ros-humble-micro-ros-agent

# 启动 agent
micro_ros_agent udp 8888

常见问题

无法连接

1. 检查飞控模式

   # 需要先切换到 Offboard 模式
   

2. 检查防火墙

   sudo ufw allow 14540/udp
   

3. 检查话题映射

控制无效

# 确认 Offboard 模式已激活
# 确认已解锁
# 检查 MAVLink 状态

相关文档

• MAVROS 文档
• PX4 ROS2
• Offboard 模式