Design of reference circuit based on STM32 quadcopter

Industrial Router Crystal 3.2*2.5mm 3225 26M (26.000MHZ) 12PF 10PPM 20PPM 30PPM

Photocoupler

A quadcopter is an aircraft that uses four rotors as a flight engine for aerial flight. Since the beginning of the 20th century, the rapid development of electronic technology has begun to be miniaturized, and incorporates artificial intelligence to make it develop into drones and intelligent robots.

The quadcopter not only realizes the flight performance of the helicopter's vertical lifting, but also reduces the design difficulty of the aircraft mechanical structure to a certain extent. The balance control system of the quadcopter consists of various inertial sensors. In the production process, the center of the overall fuselage, symmetry and motor performance requirements are lower, which is the advantage of making a four-axis aircraft, and compared to the fixed-wing aircraft, the four-axis also has a vertical take-off and landing, Good mobility and easy maintenance.

System solutions

This design uses STM32F4 as the core processor. The processor core architecture ARMCortex-M4 has high performance, low cost and low power consumption.

Overall block diagram of the design

The main control board includes the sensor MPU6050 circuit module, wireless Bluetooth module, motor start module, power management module, etc.; remote control uses commodity remote control and receiver. The control chip captures the PPM command signal of the receiver, and the IIC bus is connected between the sensor and the control chip, and the control signal is transmitted by the PWM between the MCU and the ESC.

MPU-6050 circuit schematic

Power management module

The quadcopter requires the overall design to be lighter in weight and smaller in size. Therefore, in the selection of the battery, it is most suitable to use a lithium battery that is small in size, light in weight, and large in capacity. The core chip of the system is STM32F103. The common working voltage is 3.3V. At the same time, the inertial measurement sensor, the conventional power supply voltage of the Bluetooth communication module is also 3.3V, and the voltage of the lithium battery is 11.4V. To make the system work normally, it needs to be 11.4V. The lithium battery voltage is regulated to 3.3V. The commonly used 78 series regulator chip is no longer suitable, and a better performance regulator chip must be selected.

After comprehensive consideration, this circuit uses the core chip of the LM1117-3.3 and LM2940-5 power supply parts. The battery power is reduced to 5V after the LM2940-5 is regulated to 3.3V at the input LM1117-3.3. Due to the large current of the motor part, overcurrent protection is added to the flight control circuit section, and a 500 mA fuse is used.

Editor's conclusion

This design is based on the STM32F4 four-axis aerial camera platform. With STM32F407 as the control core, the four-axis aircraft is the carrier, supplemented by the aerial camera system of the PTZ. The hardware consists of a flight control circuit, power management and other systems. It is flexible, light, malleable and adaptable. In practical applications, the quadcopter can perform specific missions in complex and dangerous environments, as well as monitor traffic, the environment, and so on.