Min-Jea Tahk

Filtering problems with kinematic constraints which may arise in target tracking problems are considered. A novel approach which treats kinematic constraints as additional fictitious or pseudomeasurements is proposed. A numerical example is provided to show the technical feasibility of the proposed idea for target tracking problems. This example shows that the proposed method can improve estimation accuracy significantly for velocity and acceleration states in the tracking problem. However, it i

This paper introduces a coevolutionary method developed for solving constrained optimization problems. This algorithm is based on the evolution of two populations with opposite objectives to solve saddle-point problems. The augmented Lagrangian approach is taken to transform a constrained optimization problem to a zero-sum game with the saddle point solution. The populations of the parameter vector and the multiplier vector approximate the zero-sum game by a static matrix game, in which the fitn

This paper addresses the problem of computing accurate time-to-go estimates, which is an important issue in implementing various optimal guidance laws developed for missiles of time-varying velocity. A recursive time-to-go computation method which updates the time-to-go in a noniterative way is presented. The recursive method includes an error compensation feature which explicitly computes the time-to-go error produced by nonzero initial heading errors. The proposed method is simple and straight

This paper proposes a novel approach for guidance law design to satisfy the impact-time constraints for a certain class of homing missiles. The proposed guidance law provides proper lateral acceleration commands that make the impact time error converge to zero by the time of impact. This scheme can be applied to any existing guidance law for which a formula of predicted time to go is available. Convergence of time-to-go errors is supported by Lyapunov stability. The optimal guidance law and the

Two-dimensional formation guidance laws for formation flight using only line-of-sight angle information are addressed. The main idea is to use the line-of-sight angles to two nearby vehicles to maintain the formation position of the current vehicle. Such a formation guidance law is useful because measurement of the line-of-sight angles does not require data communication between the vehicles. We propose two methods of using the line-of-sight angle information for formation guidance: the angle in

A linearizing transformation technique developed for the control of nonlinear systems is applied to the autopilot design of air-to-air missile systems. The plant inversion characteristic of this methodology is clearly displayed, and stability problems associated with nonminimum-phase plants are identified. To avoid the difficulty associated with the non-minimum-phase dynamics of missile acceleration, the plant inversion is first applied to the control of angle-of-attack and sideslip. Owing to si

The design, dynamics, and control allocation of tri-rotor unmanned aerial vehicles (UAVs) are introduced in this paper. A trirotor UAV has three rotor axes that are equidistant from its center of gravity. Two designs of tri-rotor UAV are introduced in this paper. The single tri-rotor UAV has a servo-motor that is installed on one of the three rotors, which enables rapid control of its motion and its various attitude changes-unlike a quad-rotor UAV that depends only on the angular velocities of f

This article proposes a hybrid optimization algorithm, which combines evolutionary algorithms (EA) and the gradient search technique, for optimization with continuous parameters. Inheriting the advantages of the two approaches, the new method is fast and capable of global search. The main structure of the new method is similar to that of EA except that a special individual called the gradient individual is introduced and EA individuals are located symmetrically. The gradient individual is propag

Abstract In this paper, optimal guidance laws for multiple vehicles formation flight are addressed. The proposed laws are obtained as state-feedback solutions of linear quadratic optimal control problems to minimize the time varying energy cost with terminal constraints on position and velocity. Since the proposed laws are able to control the flight time, they are possible to make all vehicles join the formation concurrently at a specified time. A method to compensate the acceleration or maneuve