Among the many types of UAVs, the quadrotor is widely used because of its vertical take-off and landing, strong stability, and relatively simple structure. At present, whether it is academia or industry, the research on quadrotor is deepening, and the expansion and application of quadrotor is increasing. Therefore, it is of good practical value to learn and study the technology related to quadrotor.
3D visual workshop Yufeng 250 machine physical drawing
To learn quadrotor, you must first have a good experimental platform
For beginners, due to lack of experience, it is often difficult to reasonably select and match each module, and it is easy to ignore the primary and secondary. For example, for the rack, the first thing to consider is the strength, because this is directly related to the vibration of the drone, and the vibration affects the sensor data quality, and the data quality affects the final control effect; The second thing to consider is whether it is easy to install, for example, some drones use round carbon fiber tubes as arms, which makes it difficult to install the motor horizontally, which will eventually affect the control effect of the drone.
Schematic diagram of the bottom of the drone
The motor and ESC are also crucial, and the cheap motor ESC is often not only easy to burn out, but also easy to deviate after exploding, resulting in an imbalance in the power of the drone.
ESC connection
In addition, these motor ESCs also have unseen defects, such as insufficient smooth response and large response delay. On the contrary, an excellent power system can not only ensure the high performance of the drone, but also use it for a long time, eliminating the time spent on maintenance.
In addition to the frame, motor and ESC, the matching of propeller and motor, the choice of 4S or 6S lithium battery is also very particular. Flight controllers and sensors require long-term experience to make a suitable choice.
Here, for learning and scientific research scenarios, a high-performance miniature quadcopter platform - Yufeng 250 is launched with a high-quality flight kit.
"Yufeng 250" UAV, "Yufeng 250" - Quadcopter UAV (based on PX4) [Hardware + Code]
Yufeng 250 has three advantages, one is module selection, the second is simulation kit, and the third is course support.
First of all, by selecting the appropriate module, the frame adopts a wide-side X-shaped layout, the wheelbase is 225mm, the total mass is 600g, and the battery life is 21 minutes. The Yufeng 250 supports PX4 firmware, and is equipped with IMU, magnetometer, barometer, GPS, optical flow and laser ranging modules, which support indoor and outdoor fixed-point stable hovering.
Optical flow installation
The advantages of this drone are shown in the table below:
Comparison projectThe traditional quadcopter Yufeng 250 flight controller is large in size, and it needs to install a shock absorber plate separately, which is inconvenient to install 30*30mm, small in size, and light in weight; Fixed hole installation, with its own shock absorbing ball, easy to install; Support PX4 firmware, support secondary development rack plastic frame, low strength, large vibration, the original value is often about 1g high-strength carbon fiber frame, high strength, small vibration, The measured vibration is about 0.2g, the ESC is cheap, it is easy to be damaged, it does not support the Dshot protocol, the high-quality 4-in-1 ESC is small, the peak current is 50A, it adapts to instantaneous acceleration, it supports the Dshot protocol, the motor is cheap, it is easy to damage, the response is slow, the high-performance motor is explosive, the response is fast, the number of GPS star searches is small, the positioning accuracy is low, the normal star search is about 25, the positioning accuracy is high, the optical flow and laser ranging, the smooth ground, the strong light and the weak light are common, the positioning effect is poor, the smooth ground, the outdoor sun, At night, indoor lighting and other situations can still stably locate the battery, cheap battery, short life, high-quality lithium battery, long life, remote control, conventional + send rechargeable battery kit tools, no screwdriver, motor quick release tools, etc., easy to use
Secondly, the model parameters of the UAV and the corresponding Gazebo simulation environment are provided.
Physical quantities such as the mass, moment of inertia, throttle pull curve, and lift coefficient of the drone are provided here, and with these parameters, the corresponding drone model can be built in the simulation environment.
Having a simulation environment allows you to verify the control logic on the one hand. By testing in the simulation environment, the logic problem of its own algorithm is eliminated, and the simulation effectively reduces the risk of blowing up the machine by downloading the code to the physical platform. On the other hand, the control algorithm can be verified, and when a new control algorithm is designed, it is often difficult to know how many parameters are approximately, and the order of magnitude is sometimes difficult to determine, so it can reduce the cost of manpower and material resources by adjusting it in the simulation environment. In fact, when the accuracy of the model parameters is high, the reasonable range of parameters can even be obtained according to the theory, which greatly improves the design efficiency and realizes the leap from theory to practice.
Flight controller with GPS mounting
Finally, to build a set of Yufeng 250 hardware system from scratch, we are equipped with two courses for everyone.
Courses include simulation courses and physical courses
- Simulation Course: Beginner Quadrotor Modeling and Control (MATLAB Simulation) [Theory + Practice]
The simulation course includes theoretical fundamentals and MATLAB simulation.
- Object Course: Quadrotor Modeling and Control Based on PX4
The physical course includes three modules, one is to lead the students to debug the drone and let the aircraft fly steadily; The second is to lead the students to learn the code of the PX4 control part, learn the code of this large module, and can also touch the code of other parts of PX4; The third is to lead the trainees to replace the new controller, so that the trainees can deploy the advanced control algorithms to the PX4 platform.
Physical drawing of the whole machine
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