The Research Of Output Tracking Control Allocation Algorithm About Over-actuated Aircraft

In the field of military and civil aviation, as the demand for safety and reliability aspects of the system is increasing and increasing, modern aircraft have adopted a multi-control surface arrangement. For this type of aircraft, the aerodynamic arrangement with multiple independent control effectors results in over-actuated problem. In addition to the design of multi-modal control law, in the flight control system design process, a control allocator is designed to map the total control demand onto individual actuators.In this thesis, for over-actuated aircraft control law design and control allocation, we propose a control allocation method for a particular uncertain over-actuated nonlinear system(Including the minimum phase control model and non-minimum phase control model). For the non-minimum phase control model, The corresponding control allocation law has to guarantee the commanded output to track a smooth output reference trajectory. Taking into account the control surface actuators instructions constraints, and to achieve the stabilization of the internal dynamics. Specifically speaking,The main content of the present thesis can be outlined as follows:Firstly,We have established the kinematics and dynamics of nonlinear six degrees of freedom model; then we analyze the characteristics of the phase and over-actuated. We can introduce some basic concepts of control theory, for example, the theory of finite-time convergence, nonlinear optimization and feedback linearization and so on, which lays a theoretical foundation for the theoretical derivation of control allocation.Secondly, by using the technology of feedback linearization,we have designed the corresponding control allocation algorithm for minimum phase system; and the controller has been designed and verified by simulation. performance of the algorithm can be analyzed.Thirdly,Stable inversion technique and logarithm barrier formulation have been used to design control allocation algorithm for non-minimum phase system. On the base of dynamic update law, the controller has been designed and verified by digital simulation. Simulation results of input constraints and internal dynamic show that the proposed method is right.Finally, based on a common platform of flight simulation,the aircraft’s equation of motion in the longitudinal plane of symmetry has been established. By using the dynamic update law in this thesis, we will design the corresponding controller and test control allocation algorithm correctness. Then, according to the simulation results, the algorithms in this dissertation can be compared with other control allocation algorithm, we analyze the advantages and disadvantages to verify the effectiveness of the algorithm.We propose an optimal control allocation method for a class of uncertain over-actuated affine nonlinear systems with internal dynamics. The proposed method is based on a Lyapunov design approach, and the resulting scheme is in the form of a finite-time convergent dynamic update law. The advantage of this method is computational efficiency since it is not necessary to optimize the control allocation problem exactly at each time instant. Instead, only an ordinary differential equation(ODE) defining the optimal controller has to be integrated online.