无人机降落

任务目标

无人机自主解锁，在完成飞行任务后进行自主降落

难点

难以判断是否落地然后停桨

解决方案

1. 调用mavros的服务使其自动解锁
   注：千万不要自动offboard

   • 通过rosservice list可以查阅到可调用的服务：

     /mavros/cmd/arming
     /mavros/cmd/command
     /mavros/cmd/command_ack
     /mavros/cmd/command_int
     /mavros/cmd/land
     /mavros/cmd/set_home
     /mavros/cmd/takeoff
     /mavros/cmd/trigger_control
     /mavros/cmd/trigger_interval
     /mavros/cmd/vtol_transition
     /mavros/ftp/checksum
     /mavros/ftp/close
     /mavros/ftp/list
     /mavros/ftp/mkdir
     /mavros/ftp/open
     /mavros/ftp/read
     /mavros/ftp/remove
     /mavros/ftp/rename
     /mavros/ftp/reset
     /mavros/ftp/rmdir
     /mavros/ftp/truncate
     /mavros/ftp/write
     /mavros/geofence/clear
     /mavros/geofence/pull
     /mavros/geofence/push
     /mavros/get_loggers
     /mavros/home_position/req_update
     /mavros/mission/clear
     /mavros/mission/pull
     /mavros/mission/push
     /mavros/mission/set_current
     /mavros/param/get
     /mavros/param/pull
     /mavros/param/push
     /mavros/param/set
     /mavros/rallypoint/clear
     /mavros/rallypoint/pull
     /mavros/rallypoint/push
     /mavros/set_logger_level
     /mavros/set_message_interval
     /mavros/set_mode
     /mavros/set_stream_rate
     /mavros/setpoint_position/mav_frame
     /mavros/setpoint_trajectory/mav_frame
     /mavros/setpoint_trajectory/reset
     /mavros/setpoint_velocity/mav_frame
     /mavros/vehicle_info_get
     /rosout/get_loggers
     /rosout/set_logger_level

     • 在这里调用/mavros/cmd/arming服务进行解锁
       Python代码为：

       import rospy
       from mavros_msgs.srv import SetMode, CommandBool, CommandBoolRequest
       
       def arm():
           rospy.init_node('takeoff_node', anonymous=True)
           
           # 等待连接
           rospy.wait_for_service('mavros/cmd/arming')
           
           arming_service = rospy.ServiceProxy('mavros/cmd/arming', CommandBool)
           
           # 解锁和解锁无人机
           arm_command = CommandBoolRequest(value=False)
           arming_service.call(arm_command)
       
       if __name__ == '__main__':
           try:
               arm() 
           except rospy.ROSInterruptException:
               pass

2. 调用mavros的服务使其自动降落

   • 在这里调用/mavros/set_mode服务进行模式切换，可切换的模式有：

     static const cmode_map px4_cmode_map{{
     { px4::define_mode(px4::custom_mode::MAIN_MODE_MANUAL),           "MANUAL" },
     { px4::define_mode(px4::custom_mode::MAIN_MODE_ACRO),             "ACRO" },
     { px4::define_mode(px4::custom_mode::MAIN_MODE_ALTCTL),           "ALTCTL" },
     { px4::define_mode(px4::custom_mode::MAIN_MODE_POSCTL),           "POSCTL" },
     { px4::define_mode(px4::custom_mode::MAIN_MODE_OFFBOARD),         "OFFBOARD" },
     { px4::define_mode(px4::custom_mode::MAIN_MODE_STABILIZED),       "STABILIZED" },
     { px4::define_mode(px4::custom_mode::MAIN_MODE_RATTITUDE),        "RATTITUDE" },
     { px4::define_mode_auto(px4::custom_mode::SUB_MODE_AUTO_MISSION), "AUTO.MISSION" },
     { px4::define_mode_auto(px4::custom_mode::SUB_MODE_AUTO_LOITER),  "AUTO.LOITER" },
     { px4::define_mode_auto(px4::custom_mode::SUB_MODE_AUTO_RTL),     "AUTO.RTL" },
     { px4::define_mode_auto(px4::custom_mode::SUB_MODE_AUTO_LAND),    "AUTO.LAND" },
     { px4::define_mode_auto(px4::custom_mode::SUB_MODE_AUTO_RTGS),    "AUTO.RTGS" },
     { px4::define_mode_auto(px4::custom_mode::SUB_MODE_AUTO_READY),   "AUTO.READY" },
     { px4::define_mode_auto(px4::custom_mode::SUB_MODE_AUTO_TAKEOFF), "AUTO.TAKEOFF" },
     { px4::define_mode_auto(px4::custom_mode::SUB_MODE_AUTO_FOLLOW_TARGET), "AUTO.FOLLOW_TARGET" },
     { px4::define_mode_auto(px4::custom_mode::SUB_MODE_AUTO_PRECLAND), "AUTO.PRECLAND" },}};

   • 调用示例

     import rospy
     from mavros_msgs.srv import CommandBool, CommandBoolRequest, SetMode, SetModeRequest
     set_mode_client = rospy.ServiceProxy("/mavros/set_mode", SetMode)
     set_mode_client(0,'AUTO.LAND')

附录：mavros的话题：

/mavlink/from
/mavlink/gcs_ip
/mavlink/to
/mavros/actuator_control
/mavros/altitude
/mavros/battery
/mavros/estimator_status
/mavros/extended_state
/mavros/geofence/waypoints
/mavros/global_position/compass_hdg
/mavros/global_position/global
/mavros/global_position/gp_lp_offset
/mavros/global_position/gp_origin
/mavros/global_position/local
/mavros/global_position/raw/fix
/mavros/global_position/raw/gps_vel
/mavros/global_position/raw/satellites
/mavros/global_position/rel_alt
/mavros/global_position/set_gp_origin
/mavros/hil/actuator_controls
/mavros/hil/controls
/mavros/hil/gps
/mavros/hil/imu_ned
/mavros/hil/optical_flow
/mavros/hil/rc_inputs
/mavros/hil/state
/mavros/home_position/home
/mavros/home_position/set
/mavros/imu/data
/mavros/imu/data_raw
/mavros/imu/diff_pressure
/mavros/imu/mag
/mavros/imu/static_pressure
/mavros/imu/temperature_baro
/mavros/imu/temperature_imu
/mavros/local_position/accel
/mavros/local_position/odom
/mavros/local_position/pose
/mavros/local_position/pose_cov
/mavros/local_position/velocity_body
/mavros/local_position/velocity_body_cov
/mavros/local_position/velocity_local
/mavros/manual_control/control
/mavros/manual_control/send
/mavros/mission/reached
/mavros/mission/waypoints
/mavros/nav_controller_output
/mavros/param/param_value
/mavros/radio_status
/mavros/rallypoint/waypoints
/mavros/rc/in
/mavros/rc/out
/mavros/rc/override
/mavros/setpoint_accel/accel
/mavros/setpoint_attitude/cmd_vel
/mavros/setpoint_attitude/thrust
/mavros/setpoint_position/global
/mavros/setpoint_position/global_to_local
/mavros/setpoint_position/local
/mavros/setpoint_raw/attitude
/mavros/setpoint_raw/global
/mavros/setpoint_raw/local
/mavros/setpoint_raw/target_attitude
/mavros/setpoint_raw/target_global
/mavros/setpoint_raw/target_local
/mavros/setpoint_trajectory/desired
/mavros/setpoint_trajectory/local
/mavros/setpoint_velocity/cmd_vel
/mavros/setpoint_velocity/cmd_vel_unstamped
/mavros/state
/mavros/statustext/recv
/mavros/statustext/send
/mavros/sys_status
/mavros/target_actuator_control
/mavros/time_reference
/mavros/timesync_status
/mavros/vfr_hud
/mavros/wind_estimation