Control Of The ST-3 Type Airship Thrust Vector

Unmanned airship is a lighter-than-air aircraft with the propulsion, which can be controlled in flight. With the development of technology, unmanned airship has become increasingly important, and in many areas received a new application. The flight control system, which determines various flight performance of the unmanned airship, is the core of the airship. Although the designs of a variety of unmanned airships achieve fixed high and directional flight, still the study of the ability to resist environmental interference, based on the process of airship flight, is still deficient;consequently Strengthen research in the field is necessary.Unmanned airship in flight is often subject to the impact of updraft and downdraft, which makes the airship unstable to fly and affects the implementation of the tasks. To the ST-3-type airship as the research object, a control system is designed for the impact of air flow. It is useful to decrease the impact of airflow by changing the thrust vector of the airship engines. To change the thrust vector of the airship engines means to change the direction of the engines. By changing the direction of the engines, it provides both horizontal thrust and downward or upward component to the airship, that aids the elevator to overcome the forces of the updraft or the downdraft, making the airship easy to maintain a predetermined height and improving control performance of airship. Specific tasks include the following(1) First of all, it were introduced that the composition of the airship's transmission, the force of the airship and the principle of the deflexion to the airship's thrust vectoring. (2) The work for the hardware and circuit design were made to the step motor as the controlled object. Mostly, the 8-bit SCM (single chip microcomputer) PIC16F877A was used as the control center.(3) Programming is the main part of the thesis. Assembly language is used for programming language and the programming environment is MPLAB IDE. Basing on the hardware design, the software was designed in detail.(4) Software functionality is tested when the step motor without losing the steps and that the software was reasonable has been verified.Debugging the software and hardware showed that the system met the design objective, could timely response to control commands given by operator and improved the control performance of the airship.