The problem of three-dimensional impact time control guidance considering field-of-view constraints and time-varying velocity is investigated in this study. First, considering the effect of gravity and aerodynamic forces on velocity, a simplified numerical estimation algorithm of flight time with a three-dimensional proportional navigation guidance law is derived. Then, based on the structure of the biased proportional navigation guidance law, the effect of the biased term on flight time is analyzed. The biased term is then designed to achieve impact time and field-of-view constraints considering time-varying velocity. Finally, numerical simulations are performed to demonstrate the effectiveness and superiority of the proposed guidance law.

An indirect Gauss pseudospectral method based path-following guidance law is presented in this paper. A virtual target moving along the desired path with explicitly specified speed is introduced to formulate the guidance problem. By establishing a virtual target-fixed coordinate system, the path-following guidance is transformed into a terminal guidance with impact angle constraints, which is then solved by using indirect Gauss pseudospectral method. Meanwhile, the acceleration dynamics are modeled as the first-order lag to the command. Using the receding horizon technique a closed-loop guidance law, which considers generalized weighting functions (even discontinuous) of both the states and the control cost, is derived. The accuracy and effectiveness of the proposed guidance law are validated by numerical comparisons. A STM32 Nucleo board based on the ARM Cortex-M7 processor is used to evaluate the real-time computational performance of the proposed indirect Gauss pseudospectral method. Simulations for various types of desired paths are presented to show that the proposed guidance law has better performance when compared with the existing results for pure pursuit, a nonlinear guidance law, and trajectory shaping path-following guidance and provides more degrees of freedom in path-following guidance design applications.

In this paper, an approach that considered both the continuous and discrete variables using the Gauss pseudospectral method is presented for multiphase trajectory optimization of gun-launched glide guided projectiles. The entire projectile trajectory is divided into four flight phases that connect to each other sequentially to ensure continuity. Continuous variables are utilized to describe the projectile’s state and control. Meanwhile, discrete variables are proposed to express the initial flight path angle and switching times between different flight phases. The trajectory optimization problem is posed as a constrained multiphase nonlinear optimal control problem, which is then transcribed into a nonlinear programming problem using the Gauss pseudospectral method and is finally solved using the interior point algorithm. Simulation results demonstrate the feasibility and effectiveness of this approach, as well as a detailed analysis of the key features of the trajectory parameters.

A novel attitude control scheme is proposed for a rolling aerial vehicle (RAV) with large uncertainties. Firstly, the RAV highly coupled nonlinear system is separated into attitude loop and angular loop via backstepping technique. The nominal states are calculated based on the procedure of trajectory linearization control (TLC). Then, extended state observers (ESO) are applied to estimate the uncertainties in the RAV system. Meanwhile, a feedback linearization-based controller is synthesized for the attitude loop using the estimated uncertainties, and an ESO-based sliding mode controller is synthesized for the angular rate loop. The stability of the closed-loop system is studied. Simulation results with comparisons are presented to demonstrate the feasibility of the proposed control scheme.