ROS2 机器人在静止下地图无法保存，需在移动时才能保存地图

[1157354382]

大佬 你们好
版本 20.04 foxy
在使用gmapping建好地图后，使用 map_saver无法正常保存地图，显示结果图下 日志如下

ros2 run nav2_map_server map_saver_cli 
[INFO] [1676945889.284354723] [map_saver]: 
	map_saver lifecycle node launched. 
	Waiting on external lifecycle transitions to activate
	See https://design.ros2.org/articles/node_lifecycle.html for more information.
[INFO] [1676945889.284500481] [map_saver]: Creating
[INFO] [1676945889.284764118] [map_saver]: Saving map from 'map' topic to '' file
[WARN] [1676945889.284791241] [map_saver]: Free threshold unspecified. Setting it to default value: 0.250000
[WARN] [1676945889.284822450] [map_saver]: Occupied threshold unspecified. Setting it to default value: 0.650000
[ERROR] [1676945891.288356825] [map_saver]: Failed to save the map: timeout
[INFO] [1676945891.288500232] [map_saver]: Destroying

在移动时地图就能正常保存
另附上我的tf树

[1157354382]

我似乎是找到了原因，可能是Qos没有相匹配，导致信息不能相互传输。但是具体修改哪个东西的qos我不是很懂，因为map不是gmapping自己发布的嘛，那他这个要和什么相匹配呢。
这是rviz上的日志：

ros2 run nav2_map_server map_saver_cli 
[INFO] [1677118775.546330774] [map_saver]: 
	map_saver lifecycle node launched. 
	Waiting on external lifecycle transitions to activate
	See https://design.ros2.org/articles/node_lifecycle.html for more information.
[INFO] [1677118775.546418351] [map_saver]: Creating
[INFO] [1677118775.546718313] [map_saver]: Saving map from 'map' topic to '' file
[WARN] [1677118775.546743987] [map_saver]: Free threshold unspecified. Setting it to default value: 0.250000
[WARN] [1677118775.546763269] [map_saver]: Occupied threshold unspecified. Setting it to default value: 0.650000
[WARN] [1677118775.547629798] [map_saver]: New publisher discovered on topic '/map', offering incompatible QoS. No messages will be sent to it. Last incompatible policy: DURABILITY_QOS_POLICY
[ERROR] [1677118777.547682744] [map_saver]: Failed to spin map subscription
[INFO] [1677118777.548951015] [map_saver]: Destroying

这是gmapping报错部分：

[slam_gmapping-6] [WARN] [1677118742.381892406] [slam_gmapping]: New subscription discovered on topic '/map', requesting incompatible QoS. No messages will be sent to it. Last incompatible policy: DURABILITY_QOS_POLICY

[小鱼]

@1157354382 ros2 topic info /mqp -v 可以查看详细的QOS

[1157354382]

@小鱼 感谢小鱼儿的帮助。我将 gmapping的 Durability 修改成了 transient_local ，map_saver保持一致了，也能进行保存工作。困扰了快一个星期了，感谢帮助。

[374870361]

我这里用ros2 eloquent也是gmapping建图，建好图之后直接执行

ros2 run nav2_map_server map_saver

就可以直接保存了

[374870361]

@1157354382 我在ros2 galactic中也遇到了和你一样的问题，想问下你是怎么修改gmapping的Durabiliy的呢

[1157354382]

@374870361
void SlamGmapping::startLiveSlam() 里面的内容，好像是这一块，好久没搞了

 // sst_ = this->create_publisher<nav_msgs::msg::OccupancyGrid>("map", rclcpp::SystemDefaultsQoS());
    sstm_ = this->create_publisher<nav_msgs::msg::MapMetaData>("map_metadata", rclcpp::SystemDefaultsQoS());

    scan_filter_sub_ = std::make_shared<message_filters::Subscriber<sensor_msgs::msg::LaserScan>>
            (node_, "scan", rclcpp::SensorDataQoS().get_rmw_qos_profile());
   
    sst_ = this->create_publisher<nav_msgs::msg::OccupancyGrid>("map", rclcpp::QoS(rclcpp::QoSInitialization::from_rmw(rmw_qos_profile_system_privated), rmw_qos_profile_system_privated));

//    sub_ = this->create_subscription<sensor_msgs::msg::LaserScan>(
//        "scan", rclcpp::SensorDataQoS(),
//        std::bind(&SlamGmapping::laserCallback, this, std::placeholders::_1));

我现在是使用 cartographer 来建图了，感觉也挺不错的