Design of the Hardware Scheme of the UAV Electronic Governor System

The traditional aero model DC(direct current) motor is commutated mechanically by brush and commutator, however, there is mechanical friction between the brush and commutator, which will cause noise, sparks, electromagnetic interference and many other problems. Because of the disadvantages of high manufacturing cost, short service life and difficult maintenance, the use of brush motors is restricted in many situations. The DC brushless motor is the rotation of the magnetic pole, while the armature is still. The electronic inverter is controlled by the magnetic pole position signal to supply the power to the armature. Using the electronic inverter to replace the mechanical commutator has a very obvious advantage. This paper designs a UAV(unmanned aerial vehicle) brushless motor speed controller based on SCM(single chip microcomputer), mainly in order to meet the light weight, high control precision, good stability and other special requirements of the UAV brushless motor controller. The results show that the design uses fewer components to realize the start, stop, forward and reverse rotation, acceleration and deceleration, emergency stop and other functions. Introduction In the aeromodelling field, traditional brush motor hasn’t already meet the aeromodelling system’s special requirements of the high precision, low power consumption, stability, light weight[1-2]. Brushless motor with small size, light weight, low cost, no commutation spark, no carbon brush wear, long service life, etc [3-5]. It will replace the traditional brush motor has become inevitable[6-8]. In addition, as the global price of brushless motor speed controller has greatly decreased, also make the brushless motor has been widely applied. At present, electronic products are experiencing the conversion from analog to digital, and the development of power electronics technology, computer technology and control theory makes the motor speed control technology developed rapidly[9]. The application of new power electronic devices and digital integrated circuit with high performance and advanced control theory makes the function of the control unit more perfect[10]. The number and controller required less control device volume is shrinking, which improve the reliability of the controller and the cost is lower. The Overall Hardware Scheme of the UAV Electronic Governor System The hardware of electronic governor system of UAV is mainly composed of STC89C52RC main controller, a brushless DC motor, 7407I/O driver circuit, TLP521 optocoupler isolation circuit and three-phase full bridge circuit, Holzer sensor phase detection circuit, key matrix circuit and LED digital tube display circuit. The controller STC89C52RC is used for the hardware design of UAV brushless motor speed controller based on MCU and the motor uses a 12-36V brushless motor. The drive circuit of power module comprises a 12V power supply and 5V control module. There are two isolation circuits in electronic governor system: the isolation circuit between the three-phase full bridge circuit and the 7407 microcontroller I/O port and the isolation circuit between the driving circuit of Holzer sensor phase detection circuit and the MCU P3 port. The speed display circuit of brushless motor is made up of 8th International Conference on Social Network, Communication and Education (SNCE 2018) Copyright © 2018, the Authors. Published by Atlantis Press. This is an open access article under the CC BY-NC license (http://creativecommons.org/licenses/by-nc/4.0/). Advances in Computer Science Research, volume 83