Optimization of the PNG Law for a Dual-Spin Mortar with Fixed Canards

Pengfei Liu,Hongsong Cao,Lifei Cao,Hengzhu Liu,Shunshan Feng,Xiaodong Sun

doi:10.1155/2021/1741260

Abstract

The limited instantaneous overload available and the curved trajectory lead to adaptivity problems for the proportional navigation guidance (PNG) of a guided mortar with a fixed-canard trajectory correction fuze. In this paper, the optimization of a PNG law with gravity compensation is established. Instead of using the traditional empirical method, the selection of the proportional navigation constants is formulated as an optimization problem, which is solved using an intelligent optimization algorithm. Two optimization schemes are proposed for constructing corresponding optimization models. In schemes 1 and 2, the sum squared error between the impact point and target and the circular error probability (CEP), respectively, are taken as the objective function. Monte Carlo simulations are conducted to verify the effectiveness of the two optimization schemes, and their guidance performance is compared through trajectory simulations. The simulation results show that the impact point dispersion can be efficiently reduced under both proposed schemes. Scheme 2 achieves a lower CEP, which is approximately 2.9 m and 2.4 times smaller than that achieved by scheme 1. Moreover, the mean impact point is closer to the target.

Highlights

With the increasing operational requirements regarding mortar delivery accuracy and maneuverability as well as collateral damage and round expenditure, trajectory correction mortars have received significant research attention [1,2,3,4,5,6,7].As one of the key technologies for guided ammunition, guidance methods are always a focus of research in this field [2, 8]. e proportional navigation guidance (PNG) law has computational simplicity, robustness, and implementability and has been widely used in various kinds of trajectory correction projectiles [3]
Results and Discussion e projectile used in this study is a 120 mm, fin-stabilized mortar projectile e physical properties and aerodynamic coefficients of this projectile are listed in Tables 2 and 3, respectively
Based on a PNG law with gravity compensation, two optimization schemes are proposed in which the proportional navigation constants are taken as the design variables. e objective functions of schemes 1 and 2 are the sum squared error between the impact point and target and the circular error probability (CEP), respectively

Summary

Introduction

With the increasing operational requirements regarding mortar delivery accuracy and maneuverability as well as collateral damage and round expenditure, trajectory correction mortars have received significant research attention [1,2,3,4,5,6,7].As one of the key technologies for guided ammunition, guidance methods are always a focus of research in this field [2, 8]. e proportional navigation guidance (PNG) law has computational simplicity, robustness, and implementability and has been widely used in various kinds of trajectory correction projectiles [3]. E proportional navigation guidance (PNG) law has computational simplicity, robustness, and implementability and has been widely used in various kinds of trajectory correction projectiles [3]. E limited control force and low velocity result in the availability of insufficient instantaneous overloads. The required overload due to the curved trajectories of such mortar projectiles is large and may exceed the available instantaneous overloads; as a result, such a projectile may not approach the line of sight at the angular rate specified in conventional PNG. Zhang took the horizontal velocity and position as the control variables to construct a new adaptive proportional-derivative guidance law for a guided mortar projectile [10]. It is well known that the proportional navigation constants are the key factors for the PNG law [11]. In the above-mentioned works, the proportional navigation constants were determined

Methods

Results

Conclusion