ros相关笔记

ros命令

查看package的依赖

查看直接依赖

rospack depends1 beginner_tutorials

输出

roscpp
rospy
std_msgs

查看所有依赖包(包括依赖的包 依赖的 包)
rospack depends beginner_tutorials

更改ros默认依赖的opencv

https://blog.csdn.net/qq_33161084/article/details/90914366
ros melodic使用full安装后会自动安装opencv3.2,但cmake配置文件中的依赖添加并不完整，很多时候需要手动添加需要的依赖。如果系统中存在多个版本opencv，切换版本时也可以使用接下来的方法修改配置。
配置文件地址为：/opt/ros/melodic/share/cv_bridge/cmake/cv_bridgeConfig.cmake

catkin_make不编译某些package

https://answers.ros.org/question/54181/how-to-exclude-one-package-from-the-catkin_make-build/
catkin_make -DCATKIN_BLACKLIST_PACKAGES="foo;bar"

catkin_make指定编译某个package

catkin_make -DCATKIN_WHITELIST_PACKAGES=" 你的包名"

查看cmake相关变量

比如查看CATKIN变量
在build目录
cmake -L|grep CATKIN

CATKIN_BLACKLIST_PACKAGES:STRING=vps_detect
CATKIN_DEVEL_PREFIX:PATH=/home/nano/***/devel
CATKIN_ENABLE_TESTING:BOOL=ON
CATKIN_SKIP_TESTING:BOOL=OFF
CATKIN_SYMLINK_INSTALL:BOOL=OFF
CATKIN_WHITELIST_PACKAGES:STRING=

日志相关

rosconsole will load a config file from $ROS_ROOT/config/rosconsole.config when it initializes.
rosconsole also lets you define your own configuration file that will be used by log4cxx, defined by the ROSCONSOLE_CONFIG_FILE environment variable. Anything defined in this config file will override the default config file.

A simple example:

 # Set the default ros output to warning and higher
 log4j.logger.ros=WARN
 # Override my package to output everything
 log4j.logger.ros.my_package_name=DEBUG

cd $ROS_ROOT/config
vi rosconsole.config
#
#   rosconsole will find this file by default at $ROS_ROOT/config/rosconsole.config
#
#   You can define your own by e.g. copying this file and setting
#   ROSCONSOLE_CONFIG_FILE (in your environment) to point to the new file
#
log4j.logger.ros=INFO
log4j.logger.ros.roscpp.superdebug=WARN

拷贝文件到xx目录,配置ROSCONSOLE_CONFIG_FILE环境变量=xx/rosconsole.config
日志级别分为

  • DEBUG
  • INFO
  • WARN
  • ERROR
  • FATAL

launch file相关

todo

catkin_make编译相关

要让ros将某个目录认为是一个package.则在该目录下需要有package.xml文件

rostopic

查看当前有哪些topic

查看某一topic具体内容

roslaunch file注意事项

<param name="image_detected_topic" default="$(arg image_detected_topic)"/>
不要写成
<param name="image_detected_topic" default="$(arg_image_detected_topic)"/>

python3中使用rospy

rospy在安装ros时被默认安装到了/opt/ros/kinetic/lib/python2.7/dist-packages
python3中使用需要指定PYTHONPATH.并安装 rospkg catkin_pkg
https://stackoverflow.com/questions/49758578/installation-guide-for-ros-kinetic-with-python-3-5-on-ubuntu-16-04

pip install pyyaml
pip install rospkg catkin_pkg

代码里:

import sys
print(sys.path)
sys.path.append('/opt/ros/kinetic/lib/python2.7/dist-packages')
print(sys.path)

指定了PYTHONPATH的话,会把$PYTHONPATH加到sys.path的最前面.导致某些python3的库无法使用,比如cv2.

坐标转换相关

tf2::Matrix 完成矩阵和rpy等的转换.
http://docs.ros.org/en/jade/api/tf2/html/classtf2_1_1Matrix3x3.html

  1. 查看两个坐标系之间的关系
rosrun tf tf_echo base_link odom

  1. rviz中xyz轴的颜色分别为红绿蓝.

  2. 查看系统中的tf tree

rosrun rqt_tf_tree rqt_tf_tree

  1. rpy/matrix/四元数在线转换
    https://www.andre-gaschler.com/rotationconverter/

  2. ros中tf的frame_id和child_frame_id
    表达的是frame_id这个坐标系到child_frame_id这个坐标系的变换.注意是frame坐标系到child_frame_id坐标系的变换！不是frame坐标系下的一个点变换到child_frame_id.
    比如:A和B两个坐标系.变化矩阵为T

[1.,0., 0., -1,
  0.,  1., 0., 0,
  0.,  0., 1., 0,
  0.0,           0.0,                     0.0,                     1.0,]

其对应的rpy xyz为

x:-1 y:0 z:0 roll:0 pitch:0 yaw:0

frame_id:A child_frame_id:B
表达的是A坐标系在x方向移动-1得到坐标系B. 坐标系A下的一个点pA与坐标系B下的点pB的对应关系为pA=T.dot(pB) 而不是pB=T.dot(pA)

  1. 由于要生成tf tree,所以不允许一个child frame有多个parent frame
    比如
send_tf(fame_id=A,child_frame_id=B)
send_tf(fame_id=A,child_frame_id=C)

这样是合法的.

send_tf(fame_id=B,child_frame_id=A)
send_tf(fame_id=C,child_frame_id=A)

这样是不合法的.
不合法不是说程序不能编译运行. 你可以这么发,但是lookupTransform的时候是会报错的.

Failure at 1629192966.109406812
Exception thrown:"front_camera" passed to lookupTransform argument target_frame does not exist. 
The current list of frames is:
Frame rslidar exists with parent right_camera.

ros中认定了一个frame只有能一个parent frame.详见http://wiki.ros.org/tf/FAQ

The frames are published incorrectly. tf expects the frames to form a tree. This means that each frame can only have one parent. If you publish for example both the transforms:

from "A (parent) to B (child)" and
from "C (parent) to B (child)".
This means that B has two parents: A and C. tf cannot de
  1. rostf2_ros包中有节点发送tf.
<node pkg="tf2_ros" type="static_transform_publisher" name="vehicle_rslidar_tf_fake" args="0.8 0.0 2.0 0.0 0.0 0.0 ndt_base_link rslidar_fake" />
  1. lookupTransform
xx = tf_buffer_.lookupTransform("A", "B",cluster_header_stamp, ros::Duration(2.5));

lookupTransform查询的是"A"坐标系到"B"坐标系的变换. 也即:B坐标系下的一个点p0左乘xx得到其在A坐标系下的位置.

  1. doTransform
            tf2::doTransform(p0,p1,msg_transform_stamped_xx);

p0左乘msg_transform_stamped_xx得到p1. 如果p0是点p在坐标系A下的坐标,p1是点p在坐标系B下的坐标, 那么msg_transform_stamped_xx应该是坐标系B到坐标系A的变换.即lokkupTransform("B","A",timestamp)

topic相关

  1. 回调函数不变.改变topic.
    https://stackoverflow.com/questions/17066839/unsubscribe-from-a-topic-and-subscribe-from-a-new-one-runtime-c-ros
os::NodeHandle nh;
ros::Subscriber sub = nh.subscribe("A", 1, callbackFunc);

// Do something
...

// shutdown the subscriber (this should be unnecessary)
sub.shutdown();


// Now change the subscriber
sub = nh.subscribe("B", 1, callbackFunc);
// You are no longer subscribed to topic A
  1. ros中不支持一个puber在多个topic上发送信息
posted @ 2019-09-26 14:18  core!  阅读(815)  评论(0)    收藏  举报