C ยท Robotics Systems Engineering
Troubleshooting & Diagnostics
Real robotics problems with a diagnostic procedure for each: symptoms, measurements, commands, investigation, fix and validation.
39 of 39 open. Items marked Coming soon are not yet available.
Every diagnostic follows one structure: symptoms, possible causes, measurements to collect, diagnostic commands, step-by-step investigation, corrective actions and validation after the fix. None is a bare list of causes. Entries marked Coming soon are listed so you can see the scope; their procedures are written in Phase 6.
Sensors
- LiDAR point cloud is distortedModule 02, 07, 08Walls look curved or doubled while the robot moves or turns.
- Camera and LiDAR detections do not alignModule 06, 08Projected LiDAR points land beside the object in the image.
- IMU orientation driftsModule 02, 10Roll, pitch or yaw creeps while the robot is stationary.
- GPS position jumpsModule 02, 11The reported position leaps by metres with no robot motion.
- Barometer altitude fluctuatesModule 02Altitude oscillates or steps with no change in height.
- Camera images contain motion blurModule 02, 08Feature tracking degrades when the robot moves.
- Sensor data drops intermittentlyModule 02, 04A topic stalls or loses messages at irregular intervals.
Calibration and synchronization
- Incorrect TF transformsModule 06The model or point cloud appears rotated, mirrored or offset in RViz.
- Extrinsic calibration is wrongModule 06, 10Fused data disagrees consistently by a fixed rotation or offset.
- Sensor timestamps are inconsistentModule 07Stamps jump, run backwards or differ from the ROS clock.
- Camera data is delayedModule 07Images lag the other sensors by a constant or growing amount.
- IMU and LiDAR frequencies do not matchModule 07Fusion drops or interpolates data at mismatched rates.
- Localization fails due to timestamp offsetsModule 07, 10The estimator diverges only when the robot rotates quickly.
SLAM and localization
- SLAM driftsModule 09The map bends or the trajectory does not close on revisit.
- SLAM fails in repetitive environmentsModule 09Corridors or aisles are matched to the wrong place.
- Visual tracking is lostModule 09, 10The visual system reports lost tracking or reinitializes.
- LiDAR localization becomes unstableModule 09, 12The pose oscillates or snaps between hypotheses.
- GNSS-to-indoor transition causes a pose jumpModule 12The pose steps when GNSS is dropped near a building.
- Localization covariance grows unexpectedlyModule 11, 12Reported uncertainty rises with no obvious sensor loss.
- Map and odometry frames are inconsistentModule 06, 12The map to odom transform jumps or fights with another publisher.
Compute and ROS 2
- CPU usage is too highModule 05, 17One or more cores saturate and the pipeline falls behind.
- GPU utilization is unexpectedly lowModule 05, 17The GPU idles while the CPU is the bottleneck.
- ROS 2 messages are delayedModule 17End-to-end latency grows or is much higher than the sum of its stages.
- Messages are droppedModule 17Subscribers receive fewer messages than the publisher sent.
- Memory consumption keeps increasingModule 05, 17RAM climbs steadily until a process is killed.
- Nodes stop respondingModule 17A node stops publishing or serving but the process is alive.
- ROS 2 communication fails between computersModule 20Topics are visible on one machine and empty on the other.
Navigation and control
- Robot oscillates near obstaclesModule 13, 14The robot swings left and right or dithers beside an obstacle.
- Robot fails in narrow corridorsModule 13Planning succeeds in open space and fails in doorways or corridors.
- Robot does not follow velocity commandsModule 14Measured velocity differs from the commanded velocity.
- Path planning failsModule 13The planner reports no valid path to a reachable goal.
- Robot gets stuckModule 13Recoveries repeat without progress.
- Robot works in simulation but not in realityModule 15The same software passes in simulation and fails on hardware.
- Pick-and-place failsModule 16The gripper misses, drops or collides with the object.
Deployment
- Robot stops after running for several hoursModule 03, 19Stable at first, then a shutdown or stall after a long run.
- Sensor disconnects intermittentlyModule 04A device drops off the bus or the USB/network link resets.
- Motor overheatsModule 03, 14Case temperature rises or the driver thermally limits.
- Localization fails after rebootModule 12, 19The robot cannot find its position after a restart.
- Robot behaves differently in a new environmentModule 19Tuned behavior degrades at a new site.