Over the past decade of deep exploration in the field of aerial photography, I have witnessed the breakthrough of drone technology towards miniaturization. The 21-milligram wireless flying robot (with a diameter of 9.4 millimeters) developed by the University of California, Berkeley, is reshaping human's cognitive boundaries towards flying vehicles.
This world's smallest drone, with a structural design that breaks through physical limits, adopts a bionic propeller structure and achieves wireless power supply through two neodymium-iron-boron magnets. The external magnetic field alternates to drive the propeller at 3000 rpm to generate lift, achieving sub-millimeter positioning accuracy and continuous takeoff and landing. Miniaturization brings significant limitations: it can only carry micrometer-sized sensors and has weak wind resistance (when the wind speed exceeds 0.5 m/s, the trajectory deviation can reach 300% of the drone's body length). Compared to traditional drones, its volume is reduced by nearly a thousand times, but there is still a hundredfold gap compared to the domestic 4.21-gram solar-powered drone.
The technology driven by magnetic fields pioneers a global magnetic field manipulation mode, forming a stark contrast with traditional GPS systems: the DJI Mavic 3 achieves a hovering accuracy of ±0.1 meters (with a power consumption of 200mW), while the trajectory error of micro-devices is ±2.3 millimeters (with a power consumption of only 15μW). Core technological breakthroughs include: 1. Three-dimensional trajectory manipulation: magnetic field adjustment enables hovering, sharp turns, and precise impacts; 2. Self-stabilization mechanism: the gyro effect controls the attitude deviation of 1.5m/s crosswind within 2 degrees; 3. Swarm collaboration: 5mm-scale robots demonstrate group chain movement capabilities. Current devices rely on electromagnetic coil environments, and the next generation of radio wave control technology may usher in a new era of intravascular treatment.
Prospective applications of micro air vehicles revolutionize professional aerial photography: traversing 4mm gaps to map ancient architectural tenon-and-mortise joints, delving into drainage pipes to monitor corrosion, and achieving microscopic camera movement at the mouth of a teacup (with a resolution of 50μm/pixel tested in the Forbidden City).
Cross-disciplinary application scenarios: · Disaster relief: detecting vital signs through cracks in ruins · Precision agriculture: replacing bees to complete greenhouse pollination · Medical revolution: laboratory simulation for removing cerebral thrombosis
The current equipment is not equipped with an environmental perception module, necessitating the overcoming of challenges related to autonomous obstacle avoidance and weak magnetic field control. Similar to how digital cameras heralded the imaging revolution in 1976, this technology is paving the way for new possibilities in the field of drones.
As aerial photographers, we must embrace technological innovation while also examining technological ethics. When drones can penetrate any space, balancing innovation and privacy protection will become a key issue for the industry. This technology has been granted an international patent (WO2025UCBMFD01), and its evolution deserves continuous attention.
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