Error: According to the loaded plugin descriptions the class trac_ik_kinematics_plugin/TRAC_IKKinematicsPlugin with base class type kinematics::KinematicsBase does not exist.

[hilinxinhui]

执行：

roslaunch ar_track_tracking.launch

提示以下错误信息：

[ INFO] [1644386574.337962248]: No root/virtual joint specified in SRDF. Assuming fixed joint
[ERROR] [1644386574.441486291]: The kinematics plugin (arm) failed to load. Error: According to the loaded plugin descriptions the class trac_ik_kinematics_plugin/TRAC_IKKinematicsPlugin with base class type kinematics::KinematicsBase does not exist. Declared types are  cached_ik_kinematics_plugin/CachedKDLKinematicsPlugin cached_ik_kinematics_plugin/CachedSrvKinematicsPlugin kdl_kinematics_plugin/KDLKinematicsPlugin lma_kinematics_plugin/LMAKinematicsPlugin srv_kinematics_plugin/SrvKinematicsPlugin
[ERROR] [1644386574.441528618]: Kinematics solver could not be instantiated for joint group arm.

安装对应插件即可：

sudo apt-get install ros-melodic-trac-ik-kinematics-plugin

更多详细信息请参考这里，请注意软件包名中的ROS版本。