The Obstacle Avoidance System Of Agriculture UAV
Currently, the types of sensors commonly used in obstacle avoidance applications include radar ranging, binocular vision, laser ranging, and ultrasonic ranging.
The crop UAV is affected by the complex farmland environment, the difficulty factor of obstacle avoidance is greatly increased, and the application scenarios are also very different.
What’s the principle of the obstacle avoidance system?
Common radar ranging, laser ranging and ultrasonic ranging use distance sensors. The working principle mainly relies on self-emitting electromagnetic waves or lasers, sound waves reflected the front obstacles and measuring the echo time difference to determine the distance. The echo strength reflected from the material of the detected object is also very different.
The principle of visual obstacle avoidance is to calculate the distance of each point by the difference of images, which is the same as the principle of the distance between human eyes. However, the algorithm is more complicated, and it is necessary to do image processing. The performance of the processor and the excellent algorithm are relatively high.
The general infrared perception is based on the principle of triangulation. The infrared emitter emits an infrared beam at a certain angle, and the light is reflected back after encountering the object. After the CCD detects the reflected light, the object distance can be calculated through the geometrical relationship of the structure.
However, for crop uavs, the use of other obstacle avoidance methods is not as good as the obstacle avoidance method of radar wave ranging. As far as the common visual obstacle avoidance is concerned, in the actual operation, the farmland environment often has flying dust and flying liquid medicine.
When they block the visual system, it will seriously affect the function of the visual obstacle avoidance system, resulting in accidents. Therefore, visual obstacle avoidance is not very suitable for the farmland environment, but the radar wave can be perfectly handled, which is a better choice at present.
Accuracy requirements for obstacle avoidance in adapting to farmland
Crops agriculture uavs are usually only 1-5 meters above the ground when flying on farmland, which means they will face more obstacles. For example, small trees growing in the middle of farmland, poles, and wires erected in the fields, and cable-stayed cables.
Since the cable-stayed wire is usually only 2-3 cm in diameter, it is difficult to find it from the naked eye. It is a special danger to the crops agriculture uavs. Therefore, the crops agriculture uavs has very high-performance requirements for the obstacle avoidance system.
The lower precision of the barrier system is far from meeting the obstacle avoidance requirements of the delivery drones.
Exploring obstacle avoidance methods
Now let’s talk about obstacle avoidance methods. After detecting obstacles, there are three common obstacle avoidance methods: on-site suspension, planned travel route obstacles, and autonomous obstacles.
Suspension of standby is the most basic way of handling, relatively simple and safe, and must be done when encountering major obstacles. Planning for obstacles requires exploration of obstacles before the operation and setting up obstacle avoidance routes in the flight routes.
Planning for obstacle avoidance applies to small obstacles. This method is economical and reliable and requires people to participate in daily surveys. Autonomous obstacles require the machine to evade the algorithm and regenerate the route on the machine, but after regeneration, it will face new problems, such as how far it is, how to avoid new obstacles, and so on.
Redundant obstacle avoidance actions affect the efficiency
When the action of automatically avoiding obstacles during flight, the redundant action of the agriculture drone plane will become the burden of battery life. If two obstacles are encountered on the way, the remaining power cannot be returned.
Therefore, there are still many problems to be solved in the autonomous obstacle avoidance function, and there is no practical application.
In the future, the agriculture aircraft’s obstacle avoidance system can detect peripheral obstacles in all directions without dead angles and can identify various obstacles efficiently and accurately, and escort our agriculture aircraft.
At the same time, the obstacle avoidance system can be highly integrated, modular, with a high protection level and easy to maintain to better adapt to farmland.
In the era when agriculture drones are getting hotter, agriculture uavs need to be smarter, more powerful performance and a lot of practice to select better plant protection drone obstacle avoidance systems.