Research On The Aerodynamics Characteristics Of The Helicopter With Electrically Controlled Rotor

Electrically Controlled Rotor(ECR), or so-called swashplateless rotor, is a kind of helicopter new technology proposed at the beginning of the 21 th century. The research on the aerodynamic characteristics of ECR helicopter should be based on the aerodynamic model of ECR and the flight dynamic model of ECR helicopter. In view of this, the aerodynamic model of ECR suitable for the aerodynamic analysis were firstly established; then combined with the model of other components, the flight dynamic model of ECR helicopter available for the flight characteristics analysis was built; finally, some key issues related to the aerodynamic characteristics of ECR helicopter were researched. Main research work was listed below:(1) Research on the ECR aerodynamic characteristics. Firstly, aerodynamics model of ECR was built, which was divided into four parts: aerodynamics model of airfoil with trailing edge flap was established, including unsteady aerodynamic model and look-up table based on CFD; inflow model of ECR was built, including free wake model and finite state wake model; ECR flapping response in explicit pattern and the relationship between flap control and blade pitch were derived. Then, steady control response test was conducted based on the improved ECR system, and test results verified the aerodynamic model of ECR. At last, the wind tunnel trim model of ECR was built, which was used for aerodynamic characteristics analysis of ECR in theoretical, and the aerodynamic characteristics of ECR were compared with those of conventional rotor.(2) Research on the ECR helicopter trim characteristics and handling characteristics. The flight dynamic model of ECR helicopter was built firstly. Then, based on the sample ECR helicopter, the trim characteristics of ECR helicopter were analyzed, and the impacts of key design parameter on those characteristics were summarized, the trim characteristics of ECR helicopter were also compared with those of conventional helicopter. In the end, the explicit model following control method for ECR helicopter was proposed to solve the specific coupling problem of ECR helicopter, and this method effectively improved the handling characteristics of ECR helicopter.(3) Research on the Performance enhancement of ECR helicopter using active control. First, based on the improved flight dynamic model of the ECR helicopter, the research for ECR performance enhancement in open-loop was conducted, and the mechanism through which active control affect ECR performance was summarized. Then, the conventional helicopter performance enhancement was researched, and the corresponding results were compared with those of ECR helicopter. At last, a close-loop control method suitable for ECR performance enhancement wasset up, which was based on the higher harmonic control algorithm.Through the simulation and wind tunnel test, the aerodynamic characteristics of ECR helicopter were obtained. The researches showed that, applying the active control to ECR was favorable to find out the potential of ECR, and appropriate active control could effectively enhance the ECR performance.