Zhen Ziyang

Primary exploration of nonlinear information fusion control theory

By introducing information fusion techniques into a control field, a new theory of information fusion control (IFC) is proposed. Based on the theory of information fusion estimation, optimal control of nonlinear discrete control system is investigated. All information on control strategy, including ideal control strategy, expected object trajectory and dynamics of system, are regarded as measuring information of control strategy. Therefore, the problem of optimal control is transferred into the one of information fusion estimation. Firstly, the nonlinear information fusion estimation theorems are described. Secondly, an algorithm of nonlinear IFC theory is detailedly deduced. Finally, the simulation results of manipulator shift control are given, which show the feasibility and effectiveness of the presented algorithm.

Information fusion distributed navigation for UAVs formation flight

High precision navigation is a key technique for unmanned aerial vehicles (UAVs) formation flight. A methodology for fusing data from inertial navigation system (INS), global positioning system (GPS) and vision sensor is presented. For the lead UAV, a Kalman filter based INS/GPS integrated navigation system is designed. For the wing UAV, a local Kalman filter based INS/GPS integrated subsystem and local Kalman filter based INS/Vision/JTIDS subsystem are designed, and a distributed master filter based on information fusion estimation is designed to get the absolute navigation solution of wing UAV. And then, the relative navigation between the lead UAV and the wing UAV in formation can be obtained. Simulation results verify the validity of this formation navigation architecture for UAVs. Moreover, it illustrates that the distributed information fusion INS/GPS/Vision integrated navigation system for formation UAVs has highest geodetic navigation accuracy, when comparing with INS/GPS integrated navigation system and INS/Vision integrated navigation system.

Tiltrotor aircraft attitude control in conversion mode based on optimal preview control

An attitude control method based on optimal preview control for tiltrotor aircraft in conversion mode is proposed in this paper. A nonlinear model and a linear mathematical model for a tiltrotor aircraft are given. For the attitude control problem of the aircraft, a preview controller based on the error system model is designed, which produces seven control variables signals to control the pitch, roll and yaw movements of the aircraft. The controller is composed of two parts, one is feedforward loop which fuses the future previewed information, the other is feedback loop which equals to the optimal state feedback control. Then a Dryden turbulence is added to impact the aircraft in simulation. The simulation results show that the previewed information is beneficial for improving the accuracy of attitude tracking control and capacity of resisting disturbance.

Path planning of UAVs formation based on improved ant colony optimization algorithm

Aimed at the problem about the path planning of multiple unmanned aerial vehicles (UAVs) formation in radar-threatening environment, an intelligent method based on improved ant colony optimization (ACO) algorithm is presented. To begin with, initialize the mission environment before the mathematically modeling of flight path and environment. Then, a path of a single UAV can be sought by ACO algorithm. The following step is the formation of multiple UAVs. Ultimately, a real flyable path comes out on condition that the formation remains unchanged. However, path planning based on the traditional ACO may not be the best when it comes to the fact that it may contain some dispensable routes. To solve this problem, the path is trimmed afterwards to make it more straightforward. Simulation results show that the proposed improved intelligent method have better dynamic nature and computing power.

3D scene simulation of UAVs formation flight based on FlightGear simulator

To solve the problem of scene simulation for unmanned aerial vehicles (UAVs) formation flight, a method based on FlightGear is proposed. The 3D scene simulation system scheme is designed. The formation flight control system of leader-followers is established by the Matlab/Simulink, where the flight state data of UAVs is output to the FlightGear simulator by the interface of Matlab. A 3D model of UAV is designed based on AC3D software. A friendly man-machine interface is designed, which combines the simulation data with 3D animations, to make the simulation results more exhaustive. Finally, the UAVs formation flight scene simulation results show the effectiveness of the proposed method.

Research on effects of sea states on air wake

The effect of carriers air wake, which causes severe landing error, even landing failure, is not avoidable during carrier-based aircraft landing. At the same time, carriers air wake is certainly affected by sea states. From now on, there is no research or paper discussing this phenomenon. The effects of the sea states on air wake are studied in the first time in this paper, and finally got some conclusions. Every component model of carrier air wake was built, which could be used to build the relationships between the air wake and the sea states. According to the models, the wind over deck, the pitch amplitude of carrier, and the pitch frequency are critical factors causing the variety of air wake as sea states are changed. The simulation results show that the carrier air wake is affected severely by sea states. The steady carrier-wake turbulence and the periodic ship-motion-induced turbulence are influenced more significantly, especially for the periodic component. The research results of this paper have important effect on the further studying of landing safety and air wake rejecting.

Constraints for unmanned aerial vehicles formation flight path

The constraints for flight paths of unmanned aerial vehicles (UAVs) formation in form of leader-follower are investigated in this paper. First, in order to keep the formations spatial pattern stable, a minimum turning radius for leader is derived from the limitation of UAVs velocity. Second, a formation turning controller in follower is designed, which consists of followers turning angular rate control loop to track the leaders turning angular rate and velocity control loop to keep the certain distance to the leader. Finally, the simulations are implemented on the control system to verify the effect of the path constraints.

Monte Carlo approach to the analysis of UAVs control system

Several nonlinear control theories have been implied in UAVs control system, although all of those control system can achieve control objects and satisfy control requirement, the robustness of those system is unknown. This paper introduces Monte Carlo approach which is a statistical method to the study of UAVs control systems robustness. Disturbances which are worthy to consider and detailed process are presented. And Simulation results show that, considering atmospheric turbulence and sensors noises, Monte Carlo approach is a proper tool in the analysis of the robustness of UAVs formation control system.