Research And Design Of The Miniature Unmanned Rotorcraft

The helicopter and quadrotor are very popular in miniature unmanned rotorcraft,but it is restricted to airspace environment. The high-speed rotating blade is Dangerous, and it can cause flight mission failure, if encounter obstacles. In addition, When the helicopter and quadrotor taking off or landing, they have a strict requirements such as flat terrain, because tough terrain impact on the attitude stability. In order to avoid the emergence of these serious consequences, this paper designed a coaxial and spherical aircraft, which adapt to the features of the terrain and equip with propeller protection device.First of all, according to the aircraft structure and the control system hardware, this article carries on the overall design including the structure design goal and the control system hardware plan. Based on the requirements of the aircraft, we proposed a variety of structural layout, and choosed the coaxial rotor and four rudder control. Completed the design and selection of aircraft parts and main work include: the selection of dynamic components, the implementation of components selection and the design of the aircraft body. In order to improve the reliability, feasibility and superiority of the above work, the hardware circuit of the open source flight controller is studied. We determined to use the gyroscope, accelerometer and magnetometer to provide the attitude reference system, and the barometer combined with GPS to provide the position information. At the same time, also designed the hardware circuit of the spherical aircraft, mainly including: dual STM32 control circuit, power supply circuit, SD card circuit, barometer circuit, IMU circuit and wireless communication circuit.Secondly, based on the combination of theoretical research and practical exploration, this paper discusses the multi-sensor information fusion algorithm and attitude control algorithm, and establishes the earth, aircraft and the sensor coordinate system. In order to get more accurate attitude information, the gyroscope and accelerometer were calibrated.Then, the data fusion algorithm of gyroscope and accelerometer is studied, including: linear complementary filter, gradient descent method and extended Kalman filter algorithm. By comparison, it is found that the extended Kalman filtering algorithm has higher precision and better real-time performance, which can be applied to the attitude calculation. To this end, a control model based on hovering of the aircraft is established, and the control strategy of the vehicle is established. A PI controller based on angular velocity feedback is adopted in the control of the aircraft. The aircraft control algorithm process is designed in detail, including: input capture, debug communications, serial communications, information storage and execution procedures.Finally, the spherical aircraft was tested. Taking the high precision IMU product as the reference, the sensitivity of the sensor in the static and motion state is tested. The experimental results show that the sensor data after the extended Kalman filter algorithm can meet the requirements of the attitude information of the spherical vehicle. Through many tests to determine the PID parameters, a set of good parameters were determined. The aircraft has passed a serious of test in outdoor with bad weather conditions. The flight test results show that: controller designed in this paper can effectively receive remote signal, and control the aircraft completed hover and maneuverable flight. Thus it is proved that efficiency of the structure and controller design. Related research results can provide useful reference for the design and development of similar products.