[ERROR] [1611831985.981080848]: Failed to load nodelet [/cmd_vel_mux] of type [yocs_cmd_vel_mux/CmdVelMuxNodelet] even after refreshing the cache: According to the loaded plugin descriptions the class yocs_cmd_vel_mux/CmdVelMuxNodelet with base class type nodelet::Nodelet does not exist. Declared types are SlamGMappingNodelet depth_image_proc/convert_metric depth_image_proc/crop_foremost depth_image_proc/disparity depth_image_proc/point_cloud_xyz depth_image_proc/point_cloud_xyz_radial depth_image_proc/point_cloud_xyzi depth_image_proc/point_cloud_xyzi_radial depth_image_proc/point_cloud_xyzrgb depth_image_proc/register image_proc/crop_decimate image_proc/crop_nonZero image_proc/crop_non_zero image_proc/debayer image_proc/rectify image_proc/resize image_publisher/image_publisher image_rotate/image_rotate kinect2_bridge/kinect2_bridge_nodelet nodelet_tutorial_math/Plus pcl/BAGReader pcl/BoundaryEstimation pcl/ConvexHull2D pcl/CropBox pcl/EuclideanClusterExtraction pcl/ExtractIndices pcl/ExtractPolygonalPrismData pcl/FPFHEstimation pcl/FPFHEstimationOMP pcl/MomentInvariantsEstimation pcl/MovingLeastSquares pcl/NodeletDEMUX pcl/NodeletMUX pcl/NormalEstimation pcl/NormalEstimationOMP pcl/NormalEstimationTBB pcl/PCDReader pcl/PCDWriter pcl/PFHEstimation pcl/PassThrough pcl/PointCloudConcatenateDataSynchronizer pcl/PointCloudConcatenateFieldsSynchronizer pcl/PrincipalCurvaturesEstimation pcl/ProjectInliers pcl/RadiusOutlierRemoval pcl/SACSegmentation pcl/SACSegmentationFromNormals pcl/SHOTEstimation pcl/SHOTEstimationOMP pcl/SegmentDifferences pcl/StatisticalOutlierRemoval pcl/VFHEstimation pcl/VoxelGrid stereo_image_proc/disparity stereo_image_proc/point_cloud2 [ERROR] [1611831985.981136326]: The error before refreshing the cache was: According to the loaded plugin descriptions the class yocs_cmd_vel_mux/CmdVelMuxNodelet with base class type nodelet::Nodelet does not exist. Declared types are SlamGMappingNodelet depth_image_proc/convert_metric depth_image_proc/crop_foremost depth_image_proc/disparity depth_image_proc/point_cloud_xyz depth_image_proc/point_cloud_xyz_radial depth_image_proc/point_cloud_xyzi depth_image_proc/point_cloud_xyzi_radial depth_image_proc/point_cloud_xyzrgb depth_image_proc/register image_proc/crop_decimate image_proc/crop_nonZero image_proc/crop_non_zero image_proc/debayer image_proc/rectify image_proc/resize image_publisher/image_publisher image_rotate/image_rotate kinect2_bridge/kinect2_bridge_nodelet nodelet_tutorial_math/Plus pcl/BAGReader pcl/BoundaryEstimation pcl/ConvexHull2D pcl/CropBox pcl/EuclideanClusterExtraction pcl/ExtractIndices pcl/ExtractPolygonalPrismData pcl/FPFHEstimation pcl/FPFHEstimationOMP pcl/MomentInvariantsEstimation pcl/MovingLeastSquares pcl/NodeletDEMUX pcl/NodeletMUX pcl/NormalEstimation pcl/NormalEstimationOMP pcl/NormalEstimationTBB pcl/PCDReader pcl/PCDWriter pcl/PFHEstimation pcl/PassThrough pcl/PointCloudConcatenateDataSynchronizer pcl/PointCloudConcatenateFieldsSynchronizer pcl/PrincipalCurvaturesEstimation pcl/ProjectInliers pcl/RadiusOutlierRemoval pcl/SACSegmentation pcl/SACSegmentationFromNormals pcl/SHOTEstimation pcl/SHOTEstimationOMP pcl/SegmentDifferences pcl/StatisticalOutlierRemoval pcl/VFHEstimation pcl/VoxelGrid stereo_image_proc/disparity stereo_image_proc/point_cloud2 [FATAL] [1611831985.981302245]: Failed to load nodelet '/cmd_vel_mux` of type `yocs_cmd_vel_mux/CmdVelMuxNodelet` to manager `mobile_base_nodelet_manager' [cmd_vel_mux-8] process has died [pid 6001, exit code 255, cmd /opt/ros/melodic/lib/nodelet/nodelet load yocs_cmd_vel_mux/CmdVelMuxNodelet mobile_base_nodelet_manager cmd_vel_mux/output/cmd_vel:=cmd_vel __name:=cmd_vel_mux __log:=/home/miao/.ros/log/db1e215c-6158-11eb-9af9-200db0271ba0/cmd_vel_mux-8.log]. log file: /home/miao/.ros/log/db1e215c-6158-11eb-9af9-200db0271ba0/cmd_vel_mux-8*.log
该类错误j解决
sudo apt install ros-melodic-yocs-cmd-vel-mux