Design of reference circuit for quadcopter based on STM-32

A quadcopter is an aircraft that uses four rotors as flight engines to fly in the air. Since the 20th century, the rapid development of electronic technology has led to the miniaturization of quadcopters, and the integration of artificial intelligence has led to the development of drones and intelligent robots.

The quadcopter not only achieves the vertical take-off and landing flight performance of a helicopter, but also reduces the design difficulty of the aircraft's mechanical structure to a certain extent. The balance control system of the quadcopter is composed of various inertial sensors. During the production process, the requirements for the center, symmetry and motor performance of the overall fuselage are relatively low, which is also the advantage of making a quadcopter. Compared with fixed-wing aircraft, the quadcopter also has the advantages of vertical take-off and landing, good maneuverability, and easy maintenance.

System solutions

This design uses STM32F4 as the core processor. The processor core architecture is ARM Cortex-M4, which has the characteristics of high performance, low cost and low power consumption.

Design overall block diagram

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

MPU-6050 circuit schematic

Power Management Module

The quadcopter requires a light overall design and a small size. Therefore, in terms of battery selection, a small, light, and large-capacity lithium battery is the most suitable. The core chip of the system is STM32F103, and the common operating voltage is 3.3V. At the same time, the conventional power supply voltage of the inertial measurement sensor and Bluetooth communication module is also 3.3V. The voltage of the lithium battery is 11.4V. To make the system work properly, the 11.4V lithium battery voltage needs to be stabilized to 3.3V. The commonly used 78 series voltage regulator chip is no longer applicable, and a voltage regulator chip with better performance must be selected.

After comprehensive consideration, this circuit uses the core chips of LM1117-3.3 and LM2940-5 power supply. The battery power is reduced to 5V by LM2940-5 and then input to LM1117-3.3 to stabilize the voltage to 3.3V. Since the current of the motor part is large, overcurrent protection is added to the flight control circuit part, and a 500mA fuse is used.

Editor's Notes

This design is a four-axis aerial photography platform based on STM32F4. With STM32F407 as the control core, the four-axis aircraft as the carrier, and the aerial photography system supplemented by the gimbal. The hardware consists of flight control circuits, power management and other systems. It has the characteristics of flexibility, lightness, ductility, and good adaptability. In practical applications, the four-axis aircraft can complete specific flight missions in complex and dangerous environments, and can also be used to monitor traffic and environment.