According to the TTCP geometry, change the wrap-around fins to the planar fins. Construct the flow-field then generate the grid. Utilizing the computational fluid dynamics method, the lift, drag and roll moment coefficients are computed in different angles of attack. The roll moment coefficients are computed from the flow field solution and compared with the experimental results. The results show good agreement with the experimental measurements for various flight Mach numbers. The aerodynamic characteristics of these two fins are similar to each other from the numerical solution. If consider the lift, drag and center of pressure coefficients merely, these two kinds of fins can be interchanged .But the roll moment coefficient in Wrap-Around fins and planar fins are different. They need to calculate separately.
In order to ensure the quad-rotor can track moving targets or desire trajectory accurately and quickly when face external disturbance, sliding mode control is used to overcome the system uncertainties and external disturbances. A fuzzy controller is introduced to decrease the chattering and improve performance of the system. The simulation considering external disturbance is used to test the performance of the fuzzy sliding mode trajectory tracking controller and the result shows that the fuzzy sliding mode trajectory tracking controller is feasible.
For image guided missile, in order to avoid frame collision, the maximum needed frame-angle of the seeker should not exceed the maximum available frame-angle in flight. Subjected to diameter and volume of the seeker, the required frame-angle needs to be reduced. By combination signal of frame-angle, three different improved guidance laws are discussed. By using of special developed optimization scheme, the integral proportional guidance is selected finally for its best effect. For purpose of reducing required overload of the missile, further improvement of the guidance law is generated by using variable proportional factors. The simulation results show that after using of the final improved guidance law, the maximum required frame-angle is reduced by 1.5, the required overload of the missile at the beginning of tracking is reduced from 5.8 to 2.4. According to the results, the effectiveness of the improved guidance law is verified.
It had not been explored which real-time magnitude can meet the requirement of the simulation object in computer simulation system. Taking time delay into consideration, the influence of time delay on the stability of the low-altitude and low-speed small Unmanned Aircraft Systems (UAS) flight control system had been analyzed and the real-time magnitude of the miniature hardware-in-loop (HIL) simulation system was determined. Then a miniature HIL simulation system of the UAS flight control system was designed to prove the real-time magnitude feasibility. The result shows the real-time magnitude by time delay analysis can meet the requirements of flight control system.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.