Fenghua He

A singular perturbation-based design for the integrated guidance and control

This paper considers the guidance and control problem of a flight vehicle with a seeker installed on the side of its head for avoiding the aerodynamic heating. In order to guarantee the target remaining in the seekers sight of view, the line of sight and the attitude of the flight vehicle should be under some constraints which cause coupling between the guidance and the attitude control. Therefore, the integrated guidance and control (IGC) is necessary. We first formulate the guidance and control problem of the interceptor into an IGC problem with constraints. Then, a singular perturbation-based design approach is proposed to decompose the IGC problem into the control design of the quasi-steady-state subsystem and the boundary-layer subsystem individually. The receding horizon control is applied in the control design for the two subsystems. Simulation results show the effectiveness of the proposed approach.

Nonsmooth backstepping design for a class of parametric strict-feedback nonlinear systems based on Lipschitz feedback

In order to obtain flexible feedback performance for a class of parametric strict-feedback nonlinear systems, a nonsmooth backstepping design method is developed to construct the nonsmooth feedback controller such that the feedback gain can be designed according to the prespecified regions in the state space. With the nonsmooth controller, the closed-loop system is presented to be discontinuous in the new coordinates. The trajectories of the closed-loop system satisfy a differential inclusion defined by Filippov such that all the trajectories can be shown to cross the boundary of the regions. It implies that the dynamics of the trajectories on the switching condition can be ignored.

Intrinsic Tetrahedron Formation of Reduced Attitude

Abstract In this paper, formation control for reduced attitude is studied, in which a regular tetrahedron formation can be achieved and shown to be asymptotically stable under a large family of gain functions in the control. Moreover, by further restriction on the control gain, almost global stability of the desired formation is obtained. In addition, the control proposed is an intrinsic protocol that only uses relative information and does not need to contain any information of the desired formation beforehand. The constructed formation pattern is totally attributed to the geometric properties of the space and the designed inter-agent connection topology. Besides, a novel coordinates transformation is proposed to represent the relative reduced attitudes in S 2 , which is shown to be an efficient approach to reduced attitude formation problems.

Analysis of Sliding Motion on a Nonsmooth Surface

Abstract This paper presents a comprehensive method to analyze the sliding motion on a nonsmooth surface. The dynamic behavior of the trajectory on the surface is characterized by the solution of Filippovs differential inclusion. Based on the new criterions on the relation between system trajectories and a nonsmooth surface in the state space, we discuss the sliding motion along the surface, which is processed with the help of the cross product to calculate the direction of the nonsmooth region from one side to another. This result allows us to construct sliding mode controller for more general cases, of which the switching surface can be designed Lipschitz continuous for the nonsmooth sliding motion. Finally, we provide a numerical example to illustrate water drops motion on the nonsmooth surface. It shows that the water drops motion on the surface can be precisely estimated based on the new criteria in good accordance with the physical phenomena.

Maneuver decision-making on air-to-air combat via hybrid control

In this paper, a maneuver decision-making strategy in air combat is investigated via a hybrid control theory. A Hybrid Input/Output Automaton (HIOA) model is established to describe a maneuver decision-making system for a flight vehicle in air combat.An evaluation index function is proposed considering angle, space range and acceleration of two aircraft. The two-point boundary value problem is converted into two single optimization ones, and a saddle point solution is obtained for an optimal problem. A hybrid decision-making algorithm is formulated. Simulation results show the effectiveness of the proposed method.

Switching logic design based on finite-time gain measure for a flight vehicle with multiple actuators

In this paper, the control allocation problem is discussed for a flight vehicle with multiple actuators, that is lateral jets and aerodynamic fins. The usage of aerodynamic surface is not constrained, while the usage of lateral jets has to be minimized due to the limited amount of fuel available on-board. A switching logic is employed to allocate the two actuators optimally. We formulate the control system of terminal guidance as a time-varying one. The switching control strategy is divided into two phases, and lateral jets and aerodynamic fins are adopted separately in respective phases. The switching logic, from one phase to another, is designed based on finite-time gain measure.

A finite-time gain measure and its application to coordinated targets assignment

Assigning targets to multiple flight vehicles which perform a cooperative mission becomes more involved considering the complex environments. In this paper, an coordinated target assignment scheme is proposed based on a finite-time gain measure. The target assignment problem is formulated as multiple Linear Time Varying (LTV) systems. A finite-time generalized H2 measure and its performance criterion are given for the LTV system in this paper, which can be calculated by solving a differential Riccati equation with improved Davison-Maki method. An assignment evaluation index is proposed for targets allocation considering the Zero Effect Miss distance. The targets are assigned by comparing the evaluation indexes. Simulation results are presented to show the effectiveness of the proposed method.