Control Of Quadrotor Unmanned Aerial Vehicles’s Actuators Via Digital Signal Processor

The quadrotor unmanned aerial vehicle (UAV) has a special configuration which results in better mobility, simpler structural design, and smaller comparing with other rotorcrafts. Meanwhile, the value of the quadrotor UAVs in both military use and civil use is huge, but the quadrotor has the disadvantages of complex dynamic model and environmental impact greatly which restrict its development and application, so more and more researchers have begun the research on the control quadrotor UAVs. As an important part of the quadrotor UAV systems, the actuators directly determine the quadrotor’s flying performance, so a series of research will be done about the modeling and control of the quadrotor’s actuators in this thesis.Brushless motor is often used as the actuator of quadrotor UAVs. Since the control of brushless motor might need speed measurements, so two methods of measuring motor speed which is motor speed sampling via hall sensor and terminal voltage frequency are proposed in this thesis. Both methods have its own advantages and disadvantages, which method will be used is determined by the actual implementation.A hardware architecture of computer, DSP, ESC, brushless motors and hall sensor is being designed to obtain steady state and dynamic models of the brushless motor via nonlinear regression analysis.Two controllers which are the open-loop controller and the closed-loop controller are designed for real-time motor speed control system. The open-loop control system uses steady state model which is established in the second chapter, according to motor speed and supply voltage, to calculate out the duty cycle signal of PWM wave. The closed-loop control uses fuzzy and expert PID control method to achieve brushless motor closed-loop control. This controller greatly reduces the system’s rise time, delay time, and increase the sensitivity of the brushless motor.Finally,a drive circuit is designed and two PCB boards are produced to achieve the underlying control on quadrotor UAVs. And the experiment that four brushless motors track are controlled to track the actual attitude angles obtained from the on-board IMU is completed via the two PCB boards. Through the results of these experiments, it can be concluded that the brushless motor speed control system works stably, and the desired objectives are achieved.