Trajectory Correction Projectile Research Articles

Robust Optimization Design of the Aerodynamic Shape and External Ballistics of a Pulse Trajectory Correction Projectile

To improve the tactical and technical performance of pulse correction projectiles while maintaining stability in uncertain conditions and considering practical engineering constraints, this study performs a multi-objective robust optimization design of the aerodynamic shape and external ballistics of a projectile. The study utilizes an aerodynamic force engineering algorithm and numerical trajectory calculations to obtain the projectile’s performance responses within the Latin hypercube design space. To enhance optimization efficiency, a stochastic Kriging surrogate model is established to capture the inherent uncertainty of limited input data. Ultimately, a Pareto optimal solution for the projectile is obtained using a non-dominated sorting multi-objective sparrow search algorithm. The results of this study demonstrate that the consideration of design uncertainty in the robust optimization of pulse correction projectiles leads to significant enhancements in both lateral correction ability and range while satisfying flight stability requirements. Moreover, when compared to deterministic optimization, the performance variability of the design is markedly improved. This research methodology provides valuable insights for optimizing the performance of pulse correction projectiles.

Design and Parameter Optimization of Trajectory Correction Control Strategy for Air Duct Structure Projectile

In order to make the new air duct structure trajectory correction projectile have good dynamic correction control effect, the control strategy of the projectile’s correction mechanism is studied in this paper. A design method of trajectory correction control strategy based on particle swarm optimization-cuckoo search (PSO-CS) hybrid algorithm is proposed to obtain the optimal control parameters that can make the projectile flight stable and correct accurately. Firstly, the mathematical model of the air duct structure projectile is established. Secondly, the multiobjective optimization problem is analyzed. The projectile’s correction control strategy optimization model is established by taking the start control time, the number of corrections, the correction working time, and the interval time as the control variables. The optimization model innovatively considers the influence of the correction action on the flight stability of the projectile and the influence of the start control time on the correction range. Finally, the PSO-CS hybrid algorithm is used to design the calculation method of the optimization model and solve the optimal correction working parameters. The simulation results indicate that the control strategy optimization model can be solved by the proposed calculation method. Moreover, optimal correction working parameters of the correction mechanism in the current state can be obtained. Compared with the results of using single PSO algorithm and CS algorithm, the correction scheme calculated by PSO-CS hybrid optimization algorithm is better. This correction control scheme can effectively reduce the impact point deviation and make the projectile flight stable. At the same time, the circular error probable (CEP) of the projectile after correction is reduced from 42.3 m to 4.6 m while the impact point dispersion is lowered. The research results show that the design method of correction control strategy proposed in this paper is effective for trajectory correction of the new air duct structure projectile.

Ballistic and Aerodynamic Characteristics Simulation for Trajectory Correction Projectile

Conventional ammunition easily deviates from the intended target. Its hit probability is reduced by such disturbance factors as fabrication errors, initial muzzle disturbance, initial velocity probable error, and stochastic wind effect. The effect of the above interference factors can be reduced by improving the shooting dispersion, ammunition, and gun or rocket engine structure. However, such improvements may fail to meet the operational requirements for modern warfare. Ballistic correction technique is a proposed trajectory control technique for precision strike with effective damage. Taking a 57mm calibre projectile as research object, trajectory correction projectile with different aerodynamic layouts were designed. The aerodynamic characteristic, static stability, exterior ballistic characteristic and firing density of each projectile has been studied through research method of theoretical analysis and numerical calculation. These findings are considered instrumental in the trajectory correction technology research and engineering application.

Control Strategies for Flight Stability of Trajectory Correction Projectile with Air-Ducts Structure

Aiming at the controllability of spin-stabilized projectile trajectory correction, a new two-dimensional trajectory correction projectile model with a controllable air-ducts structure suitable for the spin-stabilized projectile is proposed in this paper. Furthermore, control strategies of the projectile in the corrected configuration are studied to ensure a stable flight. The correction scheme of the projectile is innovated on the basis of the ram air control mechanism. The air-ducts structure is designed inside the projectile body, and the internal air valve is used to control the lateral air-jet to achieve trajectory correction of the projectile. This is a new two-dimensional trajectory correction scheme with a relatively simple control method. Firstly, the correction mechanism of the new air-ducts structure projectile is analyzed. Secondly, based on the dynamic equation of the projectile, the key parameters of the impulse air valve control, including the safe range of the working pulse width and frequency, are calculated, and the corresponding control strategies are proposed. Finally, the flow field of the projectile in the corrected configuration of the terminal trajectory is numerically simulated, and aerodynamic parameters of the projectile are obtained. Through stability conditions established in this paper and combined with aerodynamic parameters, the validity of the proposed projectile stable flight control strategies is confirmed. The innovations of this paper include: (1) a proposed new aerodynamic configuration model with the air-ducts structure for the spin-stabilized projectile and (2) proposed innovative stable flight control strategies of the corrected configuration projectile. The numerical simulation results show that, compared with the reference projectile without air-ducts structure, the lateral force of the air-ducts structure projectile can produce a radial correction effect on the moving projectile. The simulation results of control strategies indicate that the control strategies can ensure stable flight of the corrected configuration projectile under different conditions.

Correction-Efficiency-Coefficient-Based Trajectory Optimization for Two-Dimensional Trajectory Correction Projectile

Based on the lift-to-drag ratio of a two-dimensional trajectory correction projectile, in this paper, a novel correction efficiency coefficient model has been proposed for the trajectory optimization of a two-dimensional trajectory correction projectile, and research on the influence a correction efficiency coefficient has on the flight parameters of correction trajectory is carried out. A series of results are obtained through theoretical analysis and simulation calculations, indicating that, the smaller the value of the correction efficiency coefficient is, the stronger the correction ability of the projectile reserves. The trajectory and canard geometry of the correction section of the two-dimensional trajectory correction projectile are optimized by the Gauss pseudo-spectral method and correction efficiency coefficient, and, after taking the correction efficiency coefficient into account, the projectile can accurately hit the target and effectively eliminate the swing phenomenon of the projectile’s lateral trajectory. Meanwhile, a stable roll control command is obtained. When the diameter aspect ratio of the canard is 0.4, both the flight state quantity of the optimized projectile and the roll control command are more stable, and, when the canard shape is trapezoidal, the correction efficiency coefficient is smaller, the result of trajectory optimization is more stable, and the stability of the output roll control command is better. The research results of this paper can provide certain references for both the designs of the two-dimensional trajectory correction projectile’s trajectory and the canard geometry.

Research on Parametric Modeling Optimization of Trajectory Correction Projectile Based on FVM

Research on Parametric Modeling Optimization of Trajectory Correction Projectile Based on FVM

Disturbance-Observer-Based Sliding-Mode Attitude Control of Rotation-Isolating Rudder with Ultrasonic Motor

Rotation-isolating rudder is a type of correction mechanism widely used in two-dimensional trajectory correction projectile. In this paper, we focus on its attitude servo system, develop a disturbance-observer-based sliding-mode control method, and prove the asymptotic stability of the control method. Based on the single-axis turntable established, we test the rolling attitude control performance of the rotation-isolating rudder, and the experimental result shows the effectiveness of the control method developed.

Real‐time estimation of roll angle for trajectory correction projectile using radial magnetometers

An adaptive extend Kalman filter（EKF） is designed to estimate the roll angle for trajectory correction projectile only using radial magnetometers. By analysing the characteristics of the radial magnetometer output signal and the complex angular motion of the high-spin projectiles, the measurement equation is established. Two important measures, namely noise parameter adaptation and increasing system observation, are taken to improve the performance of the designed EKF. The novelty of this study is the proposed adaptive EKF has no requirements on the magnetometer measurement accuracy. That is the magnetometers used need not undergo a complicated calibration process. In addition, orthogonal difference method is introduced to adjust noise parameters. Finally, a series of numerical simulations and flight tests are carried out to verify the performance of the proposed method. The results show the designed adaptive EKF can effectively estimate the roll angle for the trajectory correction projectile and could be extended to practical engineering applications.

Research on Evaluation Methods of Firing Precision of Trajectory Correction Projectile

As a new type of ammunition, the trajectory correction projectile has much different ballistic characteristics than traditional uncontrolled ammunition and missile. The firing precision of trajectory correction projectile is significantly higher than that of uncontrolled projectile and lower than missile. Also the evaluation method for firing precision is different from that of uncontrolled projectile and missile. In this paper, by analyzing the calculation methods and characteristics of different firing precision evaluation indicators, the method suitable for evaluating the precision of trajectory correction projectile is determined, which provides theoretical and technical support for acceptance of trajectory correction projectile firing precision.

Design of Attitude Controller of Two-Dimensional Correction Projectile Based on UAS-SMC Method

For the spin stabilized two-dimensional trajectory correction projectiles with utation and precession phenomenon, an attitude controller with sliding mode control method and unidiational auxilairy surfaces (UAS-SMC) is proposed in this paper. And the underactuated control allocation in two-dimensional trajectory correction projectile with UAS-SMC controller is also discussed here. Simulation results show that the proposed controller can effectively control the attitude of the projectile and has strong robustness, which provides reference for engineering applications.

Research on Instability Boundaries of Control Force for Trajectory Correction Projectiles

The balance of stability and maneuverability is the foundation of the trajectory correction projectile. For the terminal correction projectile without an attitude feedback loop, a larger control force is expected which may cause an instability. This paper proposes a novel method to derive instability boundaries for the control force magnitude. No additional coordinate system is needed in this method. By introducing the concept of angular compensation matrix, the exterior ballistic linearized equations considering control force are established. The necessary prerequisite for a stable flight under control is given by the Routh stability criterion. The instability boundaries for the control force magnitude are derived. The results of example flights are 13.5% more accurate compared with that in relevant research. Numerical simulations demonstrate that if the control force magnitude lies in the unstable scope derived in this paper, the projectile loses its stability. Furthermore, the effects of the projectile pitch, velocity, and roll rate on flight stability during correction are investigated using the proposed instability boundaries.

Roll Angle Measurement for a Spinning Vehicle Based on GPS Signals Received by a Single-Patch Antenna.

Roll angle measurement is an essential technology in the trajectory correction projectiles. In this paper, an algorithm to detect the roll angle and rotational speed of a spinning vehicle is studied by using a GPS (Global Positioning System) receiver with a single side-mounted antenna. A Frequency-Locked Loop (FLL) assisted Phase-Locked Loop (PLL) is designed to obtain the attitude information from GPS signals, and the optimal parameters of this system are discussed when different rotational speeds are considered. The error estimation of this method and signal-to-noise ratio analysis of GPS signals are also studied. Finally, experiments on the rotary table were carried out to verify the proposed method. The experimental results showed that the proposed algorithm can detect the roll angle in a precision of within 5 degrees.

Research on Roll Control System for Fixed Canard Rudder of the Dual-Spin Trajectory Correction Projectile

The characteristics of high-spin, high-load and wide-range of the dual-spin trajectory correction projectile are the main design difficulties of the fixed canard rudder roll control system. Permanent magnet alternating generator within the limited space, which integrates the battery and rudder, as well as its driving and measuring system is designed based on the high-spin and dual-spin characters. Meanwhile, based on the analysis of structure and operating principle, the triple closed-loop roll control system based on parallel processors is proposed, and then the signals under strong interference are processed, completing the roll attitude solution within the whole scope of trajectory. A semi-physical simulation system is built to complete control experiments with the air torque respectively provided by torque motor and wind tunnel. The wireless transmission module has also been equipped to realize real-time display of the measured roll data on the terminal computer. The responding time is less than 0.7 s and the control precision is within ± 5°. It’s proved that the designed generator provides needful torque for control and also power supply for whole electrical circuits, saving both space and cost. It is also demonstrated that the proposed triple closed-loop roll control system has good feasibility, reliability and value in engineering application.

Firing Control Optimization of Impulse Thrusters for Trajectory Correction Projectiles

This paper presents an optimum control scheme of firing time and firing phase angle by taking impact point deviation as optimum objective function which takes account of the difference of longitudinal and horizontal correction efficiency, firing delay, roll rate, flight stability, and so forth. Simulations indicate that this control scheme can assure lateral impulse thrusters are activated at time and phase angle when the correction efficiency is higher. Further simulations show that the impact point dispersion is mainly influenced by the total impulse deployed, and the impulse, number, and firing interval need to be optimized to reduce the impact point dispersion of rockets. Live firing experiments with two trajectory correction rockets indicate that the firing control scheme works effectively.

A Study on the Aerodynamic Characteristics for a Two-Dimensional Trajectory Correction Fuze

This study researched the aerodynamic characteristics of a two-dimensional trajectory correction fuze used for the common artillery ammunition, which increases the targeting accuracy by decreasing the circular error probability. The correction fuze has a pair of fixed canard and a pair of steering canards for roll control and guidance. In this study, computational fluid dynamic (CFD) simulation is performed to study the aerodynamic characteristics of the trajectory correction fuze. The primary purpose of this performance was to predict the aerodynamic coefficients and flow field over a spin-stabilized projectile with the correction fuze. Calculation covered from-10 degrees to 10 degrees steering canards deflection over speed range from Mach 0.6 to 3. The results showed the variation law in the rotary moment of correction module and the control forces of the steering canards with the Mach varying, providing aerodynamic reference for the research of trajectory correction projectiles in the future.

Study on Aerodynamic Layout of Two-Dimension Trajectory Correction Projectile

To research aerodynamic layout of the two-dimensional correct projectile, the model of projectile under different aerodynamic layout was established. Various kinds of aerodynamic dates were obtained through aerodynamic simulation. Through the establishment of suitable for two-dimensional modified ballistic model of the projectile, the capability of correcting has been received for the different layouts of the rudder. The simulation results show, to meet the aerodynamic layout of the two-dimensional correct projectile and flight stability, the rudder is closer to the head of the projectile, the correction ability is better.

The Rotational Speed Measurement of Brushless DC Motor Based on STM32 Microcontroller

The brushless DC motor applied on the electric steering gear of trajectory correction projectiles often requires getting real-time rotational speed value. The hall sensors output the hall signals for measurement, after the integration by the D-type flip-flop, an ideal pulse can be produced. Afterwards STM32F103ZE microcontroller is used to calculate the rotational speed value of the motor by the Improved M/T method. The resolution and precision can be analyzed after getting the result. This rotational speed measurement system has high precision and good real-time characteristics. It is significant for the meaning of the correction of the steering gear.

Circuit Design and System Error Analysis Based on MR / GPS Combination Measuring Projectile Roll Angle

In the control process of trajectory correction projectile, a real-time accurate measurement of projectile roll angle information is required. Geomagnetic and GPS measurement principle is applied for the establishment of the projectile measured roll angle combinations mathematical calculation model, the designing of MR and GPS measuring circuits, and derivation of the singular points of the system and error resolution type. Numerical simulation methods are applied to verify the location of singular points of the combination of measurements and the linear spline combination of interpolation method of compensation the position of the magnetic vector error and the ellipsoid fitting calibration algorithm compensate for magnetic measurement error. The geomagnetic error has less effects on the combination of measured roll angle error, while the pitch angle and yaw angle error has greater impact on the roll angle error. Remove the singular point area, projectile roll angle error is less than 2°when measured by the combination of MR / GPS .

Modeling and Simulation of Impact Point Prediction Algorithm

Trajectory correction projectiles significantly improved shooting accuracy of conventional ammunition.This paper designed an impact point prediction algorithm based on perturbation theory, and proposed trajectory correction scheme based on the impact point prediction algorithm. Based on perturbation theory, getting samples by solving ideal trajectory and typical disturbed trajectory, and solving the coefficients of the prediction model by regression.The 6-degrees of freedom trajectory simulation shows that adopting this correction guidance law, the standard error of the longitudinal falling points of projectiles reduced significantly.

Impact Point Prediction and Analysis of Lateral Correction Analysis of Two-Dimensional Trajectory Correction Projectiles

Abstract Compared with the one-dimensional trajectory correction technology which adjusts longitudinal range, not only does the two-dimensional trajectory correction technology adjust the force in velocity direction, but also need to modulate the lateral force or trajectory (perpendicular to the vertical plane of fire direction). Therefore, the structure of control cabin of two-dimensional trajectory correction projectile (TDTCP) is more complicated than that of one-dimensional trajectory correction projectile (ODTCP). To simplify the structure of control cabin of TDTCP and reduce the cost, a scheme of adding a damping disk to the control cabin of ODTCP has been developed recently. The damping disk is unfolded at the right moment during its flight to change the ballistic drift of spin stabilized projectile. For this technical scheme of TDTCP, a fast and accurate impact point prediction method based on Extended Kalman Filter was presented. An approximate formula for predicting the ballistic drift and trajectory correction quantity was deduced. And the lateral correction capability for different fire angles and its influencing factors were analyzed. All the work is valuable for further research.