Navigation and Control of the PRISMA Formation： In-Orbit Experience

This paper presents flight results and lessons learned from the Spaceborne Autonomous Formation Flying Experiment （SAFE） conducted by the German Space Operations Center in the frame of the Swedish PRISMA technology demonstration mission. PR1SMA involves two fully autonomous formation-flying spacecraft which have been launched in June 2010 in a dawn/dusk orbit at an altitude of 750 km. SAFE represents one of the first demonstrations in low Earth orbit of an advanced guidance, navigation and control system for dual-spacecraft formations. Innovative techniques based on carrier-phase differential GPS （Global Positioning System）, relative eccentricity/inclination vectors and impulsive maneuvering are validated and tuned in orbit to achieve centimeter accurate real-time relative navigation, reliable formation keeping at the meter level and flexible formation reconfiguration capabilities. The technologies demonstrated within SAFE are considered as key precursors of future distributed satellite systems for unrivaled remote sensing and space exploration.

Cooperative Navigation for Autonomous Underwater Vehicles Based on Estimation of Motion Radius Vectors

A cooperative navigation algorithm for a group of autonomous underwater vehicles is proposed on the basis of motion radius vector estimation.Combined the dead reckoning data with the mutual range data through an acoustic communication network among the group members, the relative positioning problem can be solved. A novel approach for solving the relative positioning is presented by using a recursive trigonometry technique and extended Kalman filter(EKF). Simulation results verify the correctness and effectiveness of this navigation method.

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

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 is presented. An approximate formula for predicting the ballistic drift and trajectory correction quantity is deduced. And the lateral correction capability for different fire angles and its influencing factors are analyzed. All the work is valuable for further research.

UPF based autonomous navigation scheme for deep space probe

The autonomous "celestial navigation scheme" for deep space probe departing from the earth and the autonomous "optical navigation scheme" for encountering object celestial body are presented. Then, aiming at the conditions that large initial estimation errors and non-Gaussian distribution of state or measurement errors may exist in orbit determination process of the two phases, UPF (unscented particle filter) is introduced into the navigation schemes. By tackling nonlinear and non-Gaussian problems, UPF overcomes the accuracy influence brought by the traditional EKF (extended Kalman filter), UKF (unscented Kalman filter), and PF (particle filter) schemes in approximate treatment to nonlinear and non-Gaussian state model and measurement model. The numerical simulations demonstrate the feasibility and higher accuracy of the UPF navigation scheme.

Cooperative Search and Task Allocation Among Heterogeneous Teams of UAVs

A cooperative control method of multi-class UAV(unmanned air vehicle) team is investigated.During the mission,the UAVs perform search,classification,attack and battle damage assessment(BDA) tasks at various locations,which involves a combination of the team intelligence type of decision making combined with control,estimate and real-time trajectory optimization.The search-theoretic approach based on rate of return(ROR) maps is developed to get the cooperative search strategy.Templates are developed and views are combined to maximize the probability of correct target identification over various aspect angles.Monte Carle simulation runs for the scenario to evaluate the performance of the approach with various decision parameters,UAVs distributions and UAV team characteristics.Simulation results show that the cooperative behavior can significantly improve the operational effectiveness of UAV team,and the cooperative control allows for near optimal solution of the correlative behavior of a group of UAVs in battlefield.

Design of Neural Network Variable Structure Reentry Control System for Reusable Launch Vehicle

A flight control system is designed for a reusable launch vehicle with aerodynamic control surfaces and reaction control system based on a variable-structure control and neural network theory.The control problems of coupling among the channels and the uncertainty of model parameters are solved by using the method.High precise and robust tracking of required attitude angles can be achieved in complicated air space.A mathematical model of reusable launch vehicle is presented first,and then a controller of flight system is presented.Base on the mathematical model,the controller is divided into two parts:variable-structure controller and neural network module which is used to modify the parameters of controller.This control system decouples the lateraldirectional tunnels well with a neural network sliding mode controller and provides a robust and de-coupled tracking for mission angle profiles.After this a control allocation algorithm is employed to allocate the torque moments to aerodynamic control surfaces and thrusters.The final simulation shows that the control system has a good accurate,robust and de-coupled tracking performance.The stable state error is less than 1°,and the overshoot is less than 5%.

Optimal Gliding Guidance of Vertical Plane for Standoff Released Guided Bomb Unit

Optimal gliding guidance for a guided bomb unit in the vertical plane is studied based on nonlinear dynamics and kinematics.The guidance law is designed under minimum energy loss index.To avoid the complexity in solving two-point-boundary-value problems,the steady-state solutions of the adjoint states in regular equations are suggested to be used.With these considerations,a quasi-closed,optimal gliding guidance law is obtained.The guidance law is described by the angle of attack in a simple nonlinear equation.An iterative computation method can be easily used to get the optimal angle of attack.The further simplified direct computation algorithm for the optimal angle of attack is also given.The guidance properties are compared with those of maximum lift-to-drag angle of attack control.The simulation results demonstrate that the quasi-closed,optimal gliding guidance law can improve the gliding phase terminal performance with significant increase in the altitude and much little decrease in the speed.

Research on Robust Control of Nonlinear Fuzzy VSS for Spacecraft

The nonlinear dynamic system of spacecraft with uncertainty and coupling is analyzed and its general dynamical equation is given.The decoupling-ability and controllability are proved.Aiming at this system,a new nonlinear decoupling controlling method is put forward by synthetically using the variable structure and fuzzy theory.The simulation results show that this method is effective in tracking performances under the existence of uncertainty and outer disturbance.

Re-entry Attitude Double-loop SMC of the Spacecraft and Its Logic Selection

A spacecraft re-entry attitude control method using sliding mode control (SMC) theory is developed. The controller utilizes double-loop SMC scheme and provides the robust, de-coupled tracking of both the angular velocity and the shuttle orientation angles. In accordance with the hybrid-controlling characteristics of the aerodynamic surfaces and reaction control system of the spacecraft, the control torque commands are allocated into the actuators such as the aerodynamic surfaces and reaction control system by using the optimal control selection allocation algorithm. The simulation of the spacecraft re-entry attitude controlling demonstrates the robust, de-coupled tracking performance of the proposed method and its validity.

A Study on Missile Reentry Control Based on the Method of Feedback Linearization

In the process of missile large attack angle reentry,there exist nonlinear,strong coupling uncertainty and multi-input-multi-output(MIMO)in the movement equations,so the traditional small disturbance faces difficulties.For such situations,the method of feedback linearization is adopted to control the complex system,and the control method based on the fuzzy adaptive nonlinear dynamic inversion decoupling control of missile is proposed in the paper.According to the principle of time-scale separation,the system is separated into fast loop and slow loop,the method of dynamic inversion is applied to them,and the method of adaptive fuzzy approach is adopted to compensate for the uncertainty of the fast loop.The simulation results denote the control method in the paper has a better tracing characteristic and robustness.

Research on Airborne Electro-Optical Tracking and Sighting System Based on Fuzzy PID and H_∞ Control

Airborne electro-optical tracking and sighting system is a three-degree-of-freedom angular position servo system which is influenced by multi-disturbance,and its control system consists of stabilizing and tracking components.Stabilizing control is applied to track angular velocity order and control multi-disturbance under airborne condition,and its robustness should be very good;tracking control is applied to compensate tracking error of angular position.A mathematical model is established by taking the control of yaw loop as example.H∞ stabilizing controller is designed by taking the advantage of H∞ control robustness and combining with Kalman filter.A fuzzy control is introduced in general PID control to design a decoupled fuzzy Smith estimating PID controller for tracking control.Simulation research shows that the control effect of airborne electro-optical tracking and sighting system based on fuzzy PID and H∞ control is good,especially when the model parameters change and the multi-disturbance exists,the system capability has little fall,but this system still can effectively track a target.

5G通信技术在船舶电气控制系统中的应用

文章探讨了5G通信技术在船舶电气控制系统中的应用。5G通信技术凭借其高带宽、低时延以及高可靠性,显著提升了船舶电气系统的实时监控、远程控制以及智能电网管理能力。同时,5G通信技术在自主航行与避障系统、船岸一体化通信中发挥着关键作用。通过优化能耗管理,提升系统的灵活性和适应性,5G通信技术为船舶电气系统的智能化发展提供了重要支持。

智能割草机自主导航关键技术的研究综述

首先介绍了智能割草机市场规模和发展前景,然后概述了国内外主流智能割草机产品的功能和使用技术。随后对智能割草机采用的全球导航卫星系统导航(GNSS)、机器视觉导航、激光雷达导航和多传感器融合定位导航等4类导航技术的研究现状进行了介绍,并对它们的优势和不足进行了概括分析。研究结果显示,多传感器融合定位导航是智能割草机未来导航发展的方向。接下来介绍了智能割草机所采用的PID控制和纯跟踪算法控制等2种导航策略的研究现状。最后对智能割草机存在的问题和未来发展方向进行了总结和展望。

跨介质无人机的技术问题与解决方案分析

阐述跨介质无人机作为一种能够在不同介质(水体、空气)中自由切换的多功能飞行器,受到广泛关注。分析跨介质无人机所面临的机械结构、能源与动力系统、导航与控制系统方面的技术问题,提出相应解决方案。通过优化机械结构、改进能源系统和升级导航控制系统的措施,有效地解决跨介质无人机的技术挑战,推动其在各个应用领域的发展。

玉米播种机械的智能化设计与实现

玉米播种机械的智能系统可以提高玉米播种精度、效率及可靠性,推动农业生产的现代化和智能化。该文设计一种集播种装置、传动系统、控制单元为一体的玉米播种智能化系统,系统利用北斗/GPS导航系统实现玉米播种机田间的精准定位和路径规划,在工作过程中基于传感器采集数据实现对播种深度、行距和种子数量的实时监测和控制。田间试验表明,玉米智能播种机械在播种精度、作业效率和稳定性方面表现优异,显著减少漏播、重播和种子损坏的现象,提高了播种深度和行距的均匀性,还可以降低对操作人员技术水平的依赖,提升了机械的普及和应用潜力。研究结果可以为进一步提升农业机械的智能化水平提供技术参考,有望为现代农业的高效、精准和可持续发展作出贡献。

内河码头污染防治技术应用分类模型研究

本文构建了基于规则分类方法的内河码头污染防治技术分类模型,提出了基于政策标准要求、技术适用性、应用基础条件、污染防治效果和成本费用5个分类属性及相应的分类标准,通过建立20个分类关系规则,将不同污染防治技术划归为“应、宜、可、严禁、不提倡”5种分类标签,最后以易扬尘货物堆存粉尘防治技术为代表进行了方案应用案例分析。该分类模型可促使内河码头从更深层次、更广范围,以更高要求采取有效的污染防治措施,实现码头污染防治精准治理。

发电厂巡检机器人导航控制算法研究

针对目前发电厂巡检机器人导航控制技术中定位不准确、灵活性差等问题,提出一种基于KEA128单片机的巡检机器人导航控制算法。利用多传感器融合采集信号,建立合理的反馈控制数学模型,分别设计平衡控制、速度控制、方向控制3个方面的反馈控制系统,根据Nyquist判据计算出稳定的反馈控制系统。最后,基于MATLAB/Simulink对该控制系统的PID控制算法进行仿真分析和参数整定,结果验证了算法的有效性。该导航控制算法可为电厂巡检机器人的安全稳定运行提供理论依据,具有实际的应用价值。

电子信息技术在无人机领域的应用

介绍了电子信息技术在无人机领域的应用情况,分析了导航与控制、通信与数据传输、传感器技术、机器视觉与图像处理技术、人工智能与机器学习、地理信息系统(GIS)等在无人机领域的具体应用,提出了电子信息技术在无人机领域的应用,提高了无人机的性能和功能。分析认为,电子信息技术为无人机在各个行业的应用提供了技术支持。

基于多源感知的智能巡检机器人系统设计

为了提高智能巡检机器人巡检效果,保障电力系统稳定运行,设计基于多源感知的智能巡检机器人系统。依据多源感知原理设计,系统的硬件单元包括传感器选型单元、控制器选型单元及其边缘设备通信单元;软件模块包括多传感器模型构建模块、多传感器获取特征融合模块与巡检机器人导航控制模块。通过设计与开发,实现了智能巡检机器人系统的运行。实验数据表明,应用所设计系统获得的巡检机器人响应时延更短,巡检机器人导航距离、角度偏差数据较小,充分证实了所设计系统提高了巡检机器人巡检效果,具有较好的应用性能,能够保障电力系统稳定运行。

船舶综合导航系统发展现状及趋势展望

本文以船舶综合导航系统的介绍为切入点,阐述了船舶综合导航系统的定义及功能,由此对船舶综合导航系统的技术关键进行了研究。通过研究船舶综合导航系统的两大关键技术:导航传感器技术和导航控制技术,本文重点阐述了GPS技术、惯性导航系统(INS)、声学定位系统(SLS)和船舶自动操纵系统的技术情况,结合当前科技发展趋势,进行了展望与挑战分析,预测了船舶综合导航系统将向着智能化、自主化、可靠性等方向发展。