In the future, we have to do more fine and more precise, that is, to change 99% to 99.9%, this is the craftsman spirit. ——Dan Fan, Vice President of Innovation, Dajiang
In the nearly two hours of dialogue, this is the most profound sentence that Wang Fan impressed me. Dajiang still retains its gene-focused genes, down-to-earth attitude and the pursuit of ultimate belief.
Dajiang Elf 4
How is the craftsman spirit reflected in the products of Dajiang?
Wang Fan: "We are most proud of the precision hovering technology under complex conditions indoors and outdoors."
"Hovering" is the most basic capability of multi-rotor drones, three-dimensional position, three-dimensional angle, three-dimensional speed, three-dimensional acceleration, three-dimensional angular velocity. These fifteen states that need to be measured are all stable for multi-rotor drones. Important role.
The controller adjusts the flight attitude through a series of "cascade control": the known three-dimensional position is always locked in the hovering position, where the control amount is the hovering speed of a target, and the target hover when the aircraft is in the hovering position The speed is 0; when the aircraft deviates from the hovering position, the target hovering speed is not 0, and the direction tends to hover.
DJI's integrated navigation technology combines the advantages and disadvantages of GPS, inertial measurement components, geomagnetic compass and barometer. By processing electronic signals and merging the measured values ​​of various sensors, it is possible to obtain more accurate measurements of fifteen state quantities of the aircraft.
Wang Fan: "The AcTIve track function of Dajiang Elf 4, also known as intelligent follow-up, truly realizes visual tracking through image recognition and machine learning."
Dajiang realized a visual odometer composed of a binocular stereo vision system and inertial measurement components on the Elf 4, which is a very complex visual perception system, which not only needs to launch the plane motion of the object in the field of view through the image, but also Reverse the three-dimensional position of these objects and make multiple optimization calculations based on the three-dimensional position of these objects.
However, it is easier to implement a binocular stereo vision system similar to the human eye structure. Since an object appears in the field of view of the left and right cameras at the same time, the left and right fields have parallax, and the parallax can help solve the position of the object, which can be solved only by a simple geometric relationship. This type of technology is very mature.
Bottom binocular stereo vision system
The function similar to visual tracking is actually available in the products before Dajiang, but it was only after setting the GPS point and flying around it. Dajiang really realized the tracking based on the screen recognition technology on the Elf 4, and it has automatic obstacle avoidance throughout the process.
Wang Fan: "From indoor to outdoor, seamlessly docking, our products will not produce any offset, this is the basic, critical, core, and not other fancy features."
The Elf 4 has two sets of binocular stereo vision systems, one for forward looking and one for looking down. This design has two advantages: 1. A downward-looking binocular stereo vision system can detect the three-dimensional position of the object on the ground below to know the distance of the ground; 2. A set of binocular stereo vision systems looking forward It can be used to detect the depth of an object in the foreground scene and generate a depth map for obstacle perception.
Depth map
There are six kinds of sensors on GPS 4, GPS, inertial measurement unit, barometer, geomagnetic compass, ultrasonic module and binocular vision system. There are two sets of binocular vision systems, a total of four cameras; two inertial measurement components for dual redundant backup; two geomagnetic compasses, also double redundant. When the inertial measurement component or the geomagnetic compass in operation is seriously disturbed, the system automatically performs backup switching and switches to another sensor.
With these sensors, the integrated navigation system has been upgraded to an intelligent navigation system. Intelligent navigation technology greatly expands the space in which the aircraft can move. When there is GPS, the system can measure fifteen state quantities based on GPS. The visual odometer can still continue to operate, providing additional speed and position measurement. The value further improves the accuracy; when the GPS signal is not good, the visual odometer can take over the GPS to provide stable observations for the entire system.
Wang Fan: "Our image data transmission technology helps a wide range of aerial photography enthusiasts realize their ideas and ideas."
Lightbridge is a dedicated communication link technology developed by DJI. It can realize almost “zero delay†720p HD transmission and display. The distance is usually more than 2 kilometers, and even more than 5 kilometers in the open and without interference.
Lightbridge technology uses one-way image data transmission, similar to the data transmission form of a high-definition television broadcast tower. This technology is undoubtedly the most advanced in the current UAV map transmission, not only to minimize the image transmission delay, but also to maximize the transmission distance. In terms of technical implementation, it is precisely because Lightbridge uses a one-way broadcast data method, even if it is far away, the picture transmission delay can remain stable for about 100-200 milliseconds.
A new generation of Elf 4 aerial drones, which is equipped with a camera capable of shooting 4K/30fps and 1080p/120fps video for slow motion shooting. The lens is designed with 8 lenses, 94° viewing angle, f/2.8 aperture, and the closest focusing distance to 1 meter. Compared with the Phantom 3 camera lens, the distortion is reduced by 36% and the color difference is reduced by 56%.
In terms of photo quality, the Phantom Elf 4 camera can also shoot 12 megapixel photos in Adobe DNG RAW format, with both video and photos. The main standard for defining professional-grade and consumer-grade aerial drones, namely imaging quality, has now crossed over in Dajiang 4. As the official promo said, Dajiang provides a complete set of perfect aerial solutions.
Finally, it is appropriate to end with another sentence by Wang Fan.
Wang Fan: "We are not a company on the PPT. We will not say it everywhere before it is realized."
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