Small Gas Helicopter Autopilot Design

Unmanned Aerial Vehicle (UAV) has been made rapid development in recentdecades. The topic of this paper is derived from a small unmanned aerial gas helicopterautopilot design.Small gas helicopter manufacturing technology has become mature. We chose a90gasoline helicopter as autopilot control object. The body of the helicopter is convertedto improve overall mechanical properties. We design damping pod for circuit automaticcontrol system installation and fixed. And, we independently complete the overalldesign of hardware circuitry. The hardware circuit design tasks include the MEMSsensor signal compensation, attitude solution, flight path control, flight attitude control,and so on.The use of micro-mechanical sensor makes the system tend to be more lightweightand more compact. But MEMS sensor has its own drawbacks-low precision, easy to beinterfered with. Sensor error is a major factor in affecting the attitude algorithmaccuracy. We analyze and compensate the major error of the sensor-fixed offset andtemperature drift, establish the temperature model within0-50℃, using a polynomialcompensation. For bad values in the data, we use a normal test method to remove.Founded in the debugging process for the deterioration of the sensor accuracy problemin complex environments, we design a digital FIR filter algorithms, filter out highfrequency noise and keep the valid information. The effect is obvious.Gyroscope and inclinometer with stable low-frequency characteristics is the sourceof information on attitude algorithm. Although with excellent high frequencycharacteristics, but Gyroscope has a certain accumulation of error. We use acomplementary filter based on multi-sensor information fusion technology to correct theerror. In this paper, the rotation quaternion is used to update the attitude matrix. In orderto improve the attitude algorithm of real-time, we use the fourth-order Runge-Kuttamethod to update rotation quaternion in real time. Simulation and flight experimentsshow that this method has long-term high accuracy, and dynamic performanceadvantages.Small unmanned helicopter flight control includes path control and attitude control.For helicopter control in multi-parameter loop, we design a control algorithm ofdual-loop cascade PID that angular velocity and angle are located in internal andexternal loops. After actual flight tests, the flight control algorithm basically meetsrequirements.