Design and implementation of 3-DOF helicopter bench test system

Abstract

The scope of this project is to control the speed and the direction of dc motor using H-bridge and PWM and developing a mathematical model for the motor. It is asked to develop a 3-DOF (3 Degree Of Freedom) helicopter for laboratory experiment which is often used in control research education and analysis for the design and implementation of linear and non-linear control concepts. It is composed by three rotational joints, with the end bar carrying a pair of propellers actuated by DC motors. Measurements of the joints angles are supplied by incremental encoders. Two speed controllers based on Hbridges drivers for actuating the DC motor/propeller assemblies. Both angular measurements and control voltages provided by PC based hardware interfaces and software LABVIEW programs. Based on the identified model, a PID controller has been developed to control the speed of the motor. The simulation results show that the designed control system can guarantee high precision altitude and a good control under multi operation points