Why isn't my drone's obstacle avoidance working?

A crucial aspect of ensuring your drone's safe and reliable flight is that obstacle avoidance is activated. However, have you ever experienced the terrifying moment when obstacle avoidance fails? Why is my drone's obstacle avoidance system malfunctioning?

Let's analyze in depth the reasons for drone obstacle avoidance failure and troubleshooting methods.

What is a drone obstacle avoidance system?

Obstacle avoidance is a vital safety feature for drones. It detects and senses obstacles in the drone's flight path and automatically adjusts its trajectory to avoid collisions.

Recreational drones typically feature a three-way obstacle avoidance sensor system, detecting obstacles in front, behind, and below. Advanced drones typically feature a six-way obstacle avoidance sensor system, supporting 360° all-around obstacle detection and avoidance.

The drone's obstacle avoidance response is usually to stop or fly around the obstacle.

What is Autel drone obstacle avoidance?

Autel drones utilize visual sensors to detect obstacles in their flight path. The drone then automatically decelerates and hovers to avoid collisions.

Read more: What is Drone Obstacle Avoidance System?

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Why does drone obstacle avoidance fail?

1. Lighting Issues

Currently, most civilian and industrial drones (such as the DJI Mavic series and some Autel EVO models) primarily rely on binocular vision systems to perceive obstacles. Dimming light affects the vision system's ability to capture objects, causing recognition errors.

• In low light: When flying at dusk, night, or under dark underpasses, the visual sensors cannot acquire sufficient texture and environmental contrast, causing the obstacle avoidance system to automatically shut down or fail.
• Strong Backlighting (Direct Sunlight): When a drone flies towards strong sunlight, its sensors may experience temporary blindness, preventing it from accurately calculating the distance to objects ahead.

2. Unrecognizable "Special Materials":

Obstacle avoidance systems can misjudge objects made of certain materials. This is especially true when flying in densely built-up urban areas or close to building facades, where obstacle avoidance can become intermittent.

Mirrors and Glass Walls: Glass refracts light and reflects the sky or surrounding buildings. Visual sensors can be misled by reflections, failing to recognize them as obstacles and causing crashes.

Water surfaces: Ripples and reflections on water surfaces significantly interfere with downward-facing visual and ultrasonic sensors, preventing drones from accurately determining altitude at low altitudes.

Shock-absorbing or non-reflective textured surfaces: If facing a smooth, pure black surface or an extremely rough, light-absorbing material (such as the exterior walls of some new buildings), the visual system may be unable to extract feature points.

3. Tiny obstacles of very small size

Enabling obstacle avoidance mode does not guarantee accurate detection of all obstacles. When your flight path contains long, thin objects such as power lines, kite strings, or leafless branches, the drone may barely detect them from a distance, and when they get close, it often cannot brake or slow down in time.

Secondly, when you activate the drone's Sport Mode for high-speed outdoor flight, the drone automatically disables all obstacle avoidance sensors. Inexperienced drone pilots often crash due to this mistake.

4. Sensor Obstruction or Damage

Drone obstacle avoidance relies primarily on visual sensors. Dirt or obstruction of these sensors can cause obstacle avoidance failure.

When flying outdoors, dust, fingerprints, or moisture can interfere with the lens. Regularly maintain the drone's camera lens before and after each flight. Additionally, improperly installed stickers, propeller guards, or landing gear can obstruct the visual sensor's field of view, also causing obstacle avoidance failure.

5. Uncalibrated Software or Firmware Malfunction

Drone visual obstacle avoidance requires extremely precise mathematical models for calculation.

With accumulated flight time, minor impacts, or drastic temperature changes, the visual sensor may experience slight physical displacement.

If your drone app displays a "Vision system needs calibration" message, calibrate it immediately to avoid obstacle avoidance problems caused by sensor malfunctions.

How to avoid the risk of crashing due to obstacle avoidance failure?

1. Regular Cleaning and Calibration: Before each takeoff, wipe all obstacle avoidance sensor lenses on the drone with a dedicated lens cloth. Calibrate the camera, GPS, IMU, and other sensors every few months.

2. Understand Mode Switching: Remember that obstacle avoidance is disabled in Sport Mode (S Mode)! When flying in complex or confined environments, always switch back to Normal Mode (N/P Mode) or Stable Mode (T Mode).

3. Flight Within Visual Line of Sight (VLOS): Always keep the drone within your line of sight (VLOS). This is both legal and safe. When flying over high-voltage power lines, reflective glass, dense vegetation, or at night, your own eyes and manual control are the last and most reliable obstacle avoidance system!

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