The challenges of conducting inspections in enclosed indoor spaces lie in spatial constraints and a lack of information. In some environments, inspectors are unable to enter the space to conduct inspections due to its size; drones, with their three-dimensional maneuverability, serve as an ideal alternative to human eyes and hands for accessing complex spaces.
- Large-scale warehouse/logistics center
Equipped with vision and RFID modules, the drone autonomously flies along the aisles of the warehouse, batch-reading labels on pallets or shipping containers to perform “flying inventory.” Compared to manual mobile inspections, this method increases efficiency by more than tenfold without interrupting operations.
- Inspection of Industrial Facilities
Such as the interiors of blast furnace tops, cement silos, and large oil storage tanks. These enclosed spaces are toxic, hazardous, and oxygen-deprived. Drones equipped with collision-proof cages and high-intensity lights enter these areas to perform visual scans that generate 3D models of the interior walls, inspecting for defects such as corrosion and cracks. This replaces the extremely high-risk operations of entering these spaces via scaffolding or aerial work platforms.
- Mines and Tunnels
During work stoppages or in the aftermath of disasters, gas-sensing drones conduct aerial inspections to monitor tunnel deformation, methane concentrations (using multi-gas sensors), and roof separation, providing firsthand environmental data to support safe resumption of work or rescue operations.
- Hazardous Chemical Spill Response
Inside chemical plants, drones equipped with gas sensors are deployed first to quickly map the distribution of toxic gas concentrations and delineate evacuation and containment zones, thereby preventing personnel from being exposed to the hazardous substances.
- Security Patrols
Automated nighttime patrols of large data centers and art galleries. Drones fly along random or pre-programmed routes, using multispectral or ultra-high dynamic range cameras to detect abnormal heat sources, water stains, and unauthorized intrusions, and integrate with ground-based security systems.
Enclosed indoor environments place extremely demanding requirements on unmanned aerial vehicle systems, which must address four key challenges: “where am I,” “how do I navigate,” “can I communicate,” and “is it safe.”
In situations where GPS is completely unavailable, drones rely on visual recognition and simultaneous localization and mapping (SLAM) technology:
- Visual SLAM
Using fisheye or stereo cameras to track environmental landmarks, current mainstream solutions can achieve centimeter-level accuracy. However, low light, white walls, reflective surfaces, and moving shadows or people can cause the system to lose its position. The latest solutions integrate IMU, vision, and LiDAR to form a tightly coupled multisensor system, and incorporate an AI semantic recognition layer.
By adding semantic features such as “doors,” “shelves,” and “pipes” as constraints, these systems enhance recognition accuracy.
- Laser SLAM
Based on 2D/3D LiDAR, it is less susceptible to lighting conditions and is well-suited for dimly lit environments such as mines and storage tanks. However, it is relatively heavy and consumes a significant amount of power, and its performance tends to degrade in long corridors with repetitive geometric features.
Due to the confined indoor space and numerous moving obstacles (people, forklifts), drones cannot simply hover and wait; they must:
- Real-time local planning based on a depth camera
Constructs a real-time grid map of surrounding obstacles on the robot and performs online re-planning to smooth the trajectory.
- Bio-inspired “touch-and-follow” flight:
Upon detecting contact, the lightweight propeller shroud is allowed to glide along the surface of the object while maintaining its orientation, making it suitable for inspecting extremely narrow pipes.
- Fault-tolerant planning
In the event of a communication failure, the system must have onboard autonomous return-to-home logic that does not rely on external computing power, capable of memorizing the flight path and returning along the same route or via a safe route.
SANRAY UAV is a high-tech company specializing in comprehensive solutions for FPV, drones, and related equipment, offering proven solutions for enclosed environments.
