I recently completed a weight calibration and firmware update, but now before take off the drone is saying the weight limit has exceeded, which it hasn't. The latest warning said 'the weight of 43.5kg exceeds the maximum weight of 45.6kg'.
The drone also is very wobbly when taking off and hovering, at one point it began to lower itself back to the ground with no warnings.
Anyone else seen these issues before?
Hi Garry, Sorry for the issue you have.
It sounds like your DJI T40 drone is having issues related to weight calibration, possibly firmware or sensor calibration, and potentially with its flight stability. Here’s a breakdown of potential causes and solutions:
1. Weight Calibration Error
The fact that the drone is warning about exceeding the weight limit when it shouldn’t suggests that the weight calibration might not have been performed correctly, or there might be an issue with the sensors.
Double-check Calibration: When doing a weight calibration, make sure the drone is on a flat, stable surface and that the weight is properly centered. If the calibration wasn’t successful, try repeating it.
Firmware Impact: Sometimes, after a firmware update, sensor calibration data can become misaligned or reset, leading to incorrect readings. After the firmware update, perform a fresh weight calibration again to ensure it’s registering correctly.
2. Incorrect Load Detection
If the weight warning is still appearing, it could also be due to incorrect load detection from the drone's onboard sensors. These sensors are designed to detect the weight of the payload, including any equipment like spray tanks or cameras.
Payload Configuration: Ensure that the drone’s payload configuration is correct in the software or app. If there are any incorrect settings, like an added payload that’s not properly accounted for, this could cause the system to misinterpret the weight.
3. Flight Stability / Wobbly Hovering
The wobbling and instability during takeoff and hovering could be related to a number of factors, including:
Propeller or Motor Issues: Check the propellers for any damage or deformation. A bent or chipped propeller can cause instability. Similarly, motors that aren’t functioning properly could lead to uneven lift, causing wobbling.
IMU Calibration: The Inertial Measurement Unit (IMU) calibration might be off. When the drone is wobbly during flight or fails to maintain its position, it could be due to an IMU calibration issue. Make sure to recalibrate the IMU, as it can affect the drone’s balance and stability.
GPS Calibration: If the GPS system isn’t calibrated correctly, the drone may struggle to hold its position, which could cause it to wobble or drift. Ensure that the drone has a strong GPS signal and recalibrate it if necessary.
Firmware Update Bug: Sometimes, after a firmware update, there can be bugs or settings that interfere with the drone's performance. Check the release notes for the update to see if any known stability issues were mentioned, and consider rolling back to a previous firmware version if necessary.
4. Return-to-Land (RTL) Behavior
The fact that the drone started to lower itself back to the ground without warnings might indicate an automatic fail-safe behavior, possibly triggered by the drone detecting abnormal conditions such as instability, an over-limit weight reading, or low battery. Ensure that the following are in order:
Battery Health and Voltage: Check the battery’s health and voltage. A low or unhealthy battery might cause the drone to return to land unexpectedly.
Failsafe Settings: Review the failsafe settings in the drone’s flight control app to see if it’s set to automatically land or return to home when certain conditions are met (e.g., weight limit exceeded, low battery).
Next Steps:
Recalibrate Sensors: Try recalibrating the weight, IMU, and possibly the GPS.
Check Firmware Update: If possible, roll back to the previous firmware version to see if the issue persists.
Inspect Hardware: Look for any physical issues with the propellers, motors, or other components.
Consult DJI Support: If the problem continues, especially after re-calibration, Please let us know for further investigation.
If any of the issues persist after troubleshooting, it might be a good idea to take the drone to a service center for a professional inspection, especially if it’s still under warranty. Regards Technical supporting team RUJ DRONES