Coupled Dynamics and Integrated Control for Position and Attitude Motions of Spacecraft:A Survey

Inspired by the integrated guidance and control design for endo-atmospheric aircraft,the integrated position and attitude control of spacecraft has attracted increasing attention and gradually induced a wide variety of study results in last over two decades,fully incorporating control requirements and actuator characteristics of space missions.This paper presents a novel and comprehensive survey to the coupled position and attitude motions of spacecraft from the perspective of dynamics and control.To this end,a systematic analysis is firstly conducted in details to show the position and attitude mutual couplings of spacecraft.Particularly,in terms of the time discrepancy between spacecraft position and attitude motions,space missions can be categorized into two types:space proximity operation and space orbital maneuver.Based on this classification,the studies on the coupled dynamic modeling and the integrated control design for position and attitude motions of spacecraft are sequentially summarized and analyzed.On the one hand,various coupled position and dynamic formulations of spacecraft based on various mathematical tools are reviewed and compared from five aspects,including mission applicability,modeling simplicity,physical clearance,information matching and expansibility.On the other hand,the development of the integrated position and attitude control of spacecraft is analyzed for two space missions,and especially,five distinctive development trends are captured for space operation missions.Finally,insightful prospects on future development of the integrated position and attitude control technology of spacecraft are proposed,pointing out current primary technical issues and possible feasible solutions.

Relative Position and Attitude Control for Drag-Free Satellite with Prescribed Performance and Actuator Saturation

An adaptive prescribed performance control scheme is proposed for the drag free satellite in the presence of actuator saturation and external disturbances.The relative translation and rotation dynamics between the test mass and outer satellite are firstly derived.To guarantee prescribed performance bounds on the transient and steady control errors of relative states,a performance constrained control law is formulated with an error transformed function.In addition,the requirements to know the system parameters and the upper bound of the external disturbance in advance have been eliminated by adaptive updating technique.A command filter is concurrently used to overcome the problem of explosion of complexity inherent in the backstepping control design.Subsequently,a novel auxiliary system is constructed to compensate the adverse effects of the actuator saturation constrains.It is proved that all signals in the closed?loop system are ultimately bounded and prescribed performance of relative position and attitude control errors are guaranteed.Finally,numerical simulation results are given to demonstrate the effectiveness of the proposed approach.

Design of trotting controller for the position-controlled quadruped robot

This work presents a controller designed for position-controlled quadrupedal dynamic locomotion,aiming at simple and robust trotting control. The controller takes the torso attitude angles and velocities into planning foot trajectories. Firstly design of the servo motor actuated quadruped robot is introduced and the kinematic equations are deduced. Then a scheme is presented for controlling the robot torso attitude based on the virtual leg model. Furthermore,it demonstrates the design of the controller which enables the robot to have a wide range of trotting gaits and omni-directional motions. Finally,results of robust trotting in various speeds,path tracking and push recovery in simulation are reported,and results of trotting on real quadruped robots will be studied.

ANALYSIS OF LOCATION ACCURACY FOR AN EMITTER USING SATELLITE-MOUNTED INTERFEROMETER

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Research on a combinatorial control method for coaxial rotor aircraft based on sliding mode

Aiming at the position and attitude tracking of coaxial rotor aircraft(CRA),this paper proposes a combinatorial control method of sliding mode control(SMC)coupled with proportional-integralderivative control(PIDC).Considering the complete description of flight dynamics,aerodynamics and airflow interference,the dynamical model of CRA is established.The dynamical model is simplified according to the actual flight,then the simplified dynamical model is divided into two subsystems:a fully-actuated subsystem and an under-actuated subsystem.The controller of the fully-actuated subsystem consists of a SMC controller coupled with a rate bounded PIDC controller,while the controller of the under-actuated subsystem is composed of a SMC controller.The sliding manifold is defined by combining the position and velocity tracking errors of the state variables for each subsystem.Lyapunov stability theory is used to verify the stability of the sliding mode controller,which ensures that all state trajectories of the system can reach and stay on the sliding mode surface,the uncertainty and external interference of the model are compensated.Simulation and experiment compared with the conventional PIDC are carried out,the results demonstrate the effectiveness and the robustness of the proposed control method of this paper.

Composite anti-disturbance position and attitude control for spacecrafts with parametric uncertainty and flexible vibration

The rendezvous and proximity operations with respect to a tumbling non-cooperative target pose high requirement for the position and attitude control accuracy of servicing spacecraft.However,multiple disturbances including parametric uncertainties,flexible vibration,and unknown nonlinear dynamics degrade the control performance significantly.In order to enhance the system anti-disturbance ability,this paper proposes a composite anti-disturbance control law for the spacecraft position and attitude tracking.Firstly,the relative position and attitude dynamic models with multiple disturbances are established,where the refined descriptions of multiple disturbances are accomplished based on their characteristics.Then,by combining a dual Disturbance ObserverBased Control(DOBC)and a sliding mode control,a composite controller with hierarchical architecture is proposed,where the dual DOBC in the feedforward channel is used to reject the flexible vibration,environment disturbance,and complicated nonlinear dynamics,while the parametric uncertainties are attenuated by the sliding mode control in the feedback channel.Stability analysis is carried out for the closed-loop system by unifying the sliding mode dynamics and observer dynamics.Finally,the effectiveness of the proposed controller is verified via numerical simulation and hardware-in-the-loop test.

城市无人机航线飞行间隔与调控频率综合研究

聚焦城市无人机航线飞行,为确保运行安全,需要为无人机配备合适的飞行间隔。面向同航线纵向飞行场景,研究了考虑冲突频率与碰撞概率且符合ICAO间隔制定原则的间隔调控模型。通过研究仅考虑无人机定位误差下的碰撞风险,得到无人机纵向飞行间隔,作为后续间隔计算的基准;通过综合考虑定位误差和速度误差引发的位置不确定性,计算伴随无人机航线飞行进程的碰撞风险。加大纵向间隔会延迟突破安全目标水平的时机,但随着飞行进程的推进,碰撞风险终将突破安全目标水平。基于此,提出了无人机位置调控机制,对2架无人机位置进行定期调控,以消除速度所产生的累积误差。针对某1个指定的安全目标水平,得到了纵向间隔与位置调控频率的关系曲线,发现二者存在博弈关系,实施高频调控,需要采取更小的航线间隔;反之,则需要加大航线间隔。同时,为兼顾城市空间与位置调控能力的双重约束,提出了选取曲率最大值位置的所需飞行间隔与调控频率作为折中方案,发现安全目标水平要求越严格,所需调控频率和飞行间隔越大。实验得到在满足安全目标水平为5×10^(-9)次/飞行小时情况下,所需调控频率为87次/h,所需纵向飞行间隔为90 m;同时在实际运行环境中,应用上述评估模型与方法可以客观选择所需间隔和调控频率。本文研究可以兼顾城市物流无人机空中运行的安全,提高城市空域利用率和派送效率。

Long March 6A and Its Technical Characteristics

China’s first solid-liquid bundled launch vehicle,the Long March 6 A(LM-6 A)successfully adopted a number of key new technologies,launching the Pujiang 2 and Tiankun 2 satellites precisely into their predetermined orbits,thus demonstrating that China has mastered solid-liquid bundled launch vehicle technology and has a new member in the new generation launch vehicle family.For the first time in China,a booster adopted a 2 m-diameter solid motor and a 270 V,20 k W high-voltage and high-power electric servo system was used to control the swing of the solid motor nozzles.A health diagnosis system for the core first stage engine and unattended automation technology were also adopted for the first time.

面向变构型飞行器的强化学习位置姿态一体化控制方法

针对变构型飞行器在飞行过程中由于构型发生改变导致其质心、气动力、转动惯量和气动力矩以及飞行器的抗扰能力等参数或特性发生变化,对飞行器飞行控制品质产生较大影响的问题,提出一种基于强化学习的变构型飞行器一体化位置姿态控制方法,通过孪生延迟深度确定性策略梯度(TD3)强化学习算法训练神经网络控制律,实现变构型飞行器的一体化位置姿态控制。算法通过数学仿真与飞行试验进行了验证,仿真结果与飞行试验结果表明,该算法所设计的神经网络控制律能够实现变构型飞行器的一体化位置姿态控制,并对于外界干扰具有较强的适应能力。

面向机器人加工复杂轮廓误差控制的策略研究

针对机器人加工复杂曲面零件,提出一种面向加工轮廓误差的控制策略。通过向量的形式定义了机器人加工任务的轮廓误差,结合双向搜索、斐波那契搜索和球面线性插补算法,对机器人轮廓误差进行了估计;在此基础上通过将加权轮廓误差分量补偿到机器人任务空间的速度指令中,设计了机器人加工任务的轮廓控制策略。实验结果表明:对于位置和姿态轮廓误差,估计值与真实值的差异非常小,且与单纯的跟踪控制相比,位置和方向轮廓平均误差大约降低了30%,验证了所提加工轮廓误差控制策略的有效性。

基于预定义时间的四旋翼滑模控制

针对四旋翼位置环和姿态环的控制问题,使得四旋翼位姿能够在预定时间内稳定,提出一种基于预定义时间滑模控制算法的位姿控制器。该控制器通过对四旋翼位置环和姿态环2个环节的控制,使得四旋翼的位姿能够在预定时间内稳定。理论推导及数值仿真表明:所提算法具有正确性;仿真结果表明:应用所提控制器的四旋翼的位置和姿态能够在预定时间内达到稳定。

基于干扰补偿的四旋翼无人机轨迹跟踪控制

针对带有未知外部扰动的四旋翼无人机轨迹稳定跟踪问题,设计了一种基于干扰补偿的控制策略。针对四旋翼无人机位置环设计PID位置控制器,并基于干扰估计器对外部干扰进行补偿。通过姿态解算得到期望姿态,并针对四旋翼无人机姿态环设计具有强鲁棒性能的INDI姿态控制器,通过Simulink进行仿真对比试验。实验结果表明,该控制策略可实现带有未知外部扰动条件下的四旋翼无人机轨迹跟踪能力。

静不稳定航弹弹道初始段姿态控制方法研究

某种采用折叠弹翼结构的航空制导炸弹在弹射投放后延迟展开弹翼且弹翼展开前具有较大的静不稳定度。针对航弹静不稳定状态下的机弹分离安全问题和姿态控制问题,提出了一种基于改进扩张状态观测器补偿的非奇异终端滑模控制方法。该方法利用滑模控制的强鲁棒性应对机弹分离过程中的各种外界扰动和内部不确定性,为了抑制控制抖振,设计了一种时变带宽的改进扩张状态观测器对系统总不确定项进行估计,从而形成补偿控制信号以改善控制效果,并证明了控制系统的Lyapunov稳定性和有限时间收敛性。仿真结果表明:所设计的方法能够实现弹道初始段弹体姿态的快速稳定控制且具有较高的控制品质,保证了机弹分离的安全性,同时为中制导创造了良好的初始条件。

排球训练机器人扣球位姿修正中的解耦控制

因排球训练机器人在扣球位姿控制过程中需要多回路控制,不同控制回路之间相互影响,导致存在不同回路之间的耦合干扰,要获得良好的训练效果,需要对排球训练机器人在扣球训练过程中的耦合干扰进行解耦控制。为此,提出一种针对排球训练机器人扣球位姿修正的解耦控制方法。根据机器人的主要能量和扣球速度独立非线性项计算排球机器人姿态运动参数,采用扩展卡尔曼滤波器,估计机器人在扣球训练过程中的位姿。根据机器人位姿估计结果,建立位姿修正解耦控制的目标函数,并设定扣球位姿控制的约束参量,引入变步长动态平衡反馈调节方法实现单一回路的解耦控制。实验结果表明:这种解耦控制方法在x轴和y轴中的跟踪误差均低于0.3m,在控制过程中的俯仰角、关节旋转角度和加速度变化曲线与设定期望值相符,证明所提方法可有效提高排球训练机器人的跟踪精度和控制效果,获得较好训练效果。

低成本惯性多冗余导航控制一体机设计

为了智能体的精确定位和定姿,实现其稳定运动控制,设计了一种低成本多惯性冗余导航控制一体机,给出了设计方法。稳压电路的开关电源MP2482DN和线性电源JW29300U-3.3V为一体机提供稳定5 V和3.3 V的较大功率电源;控制器STM32H7的SPI采用星形拓扑总线与3片六轴惯性芯片BMI088通信,2路TTL串口与差分卫星定位板双向通信,实现智能体定位和定姿;控制器STM32F4的CAN总线接口与智能体底盘双向通信,实现其运动控制,1路TTL串口实现与控制器STM32H7的双向通信;两控制器的网络接口与上位机组成无线局域网,实现数据交换和状态监控。整个系统具有功耗低、体积小、成本低、接口丰富的特点。

力位协同控制下的机翼壁板定位及柔性调姿技术

调姿过程中受力节点的错误选定会导致机翼壁板的承力能力大幅下降,因此准确定位受力节点才能降低壁板调姿偏差;为此,针对力位协同控制下的机翼壁板定位及柔性调姿技术展开研究;按照力位协同控制原则,建立机翼壁板的力位结构模型;并根据力学协同作用描述条件,求解机翼力位的阻抗作用效果;再通过齐次变换定位坐标的方式,推导具体的机翼壁板定位模型,实现基于力位协同控制的机翼壁板定位;分析机翼壁板的柔性等效力作用,参考调姿位移计算结果,确定位移绝对向量,定义调姿自由点所处位置,并完成柔性调姿目标模型的构建,实现力位协同控制下机翼壁板定位及柔性调姿方法的设计;实验结果表明,上述算法的应用,可将调姿受力节点与标准受力点之间的定位坐标误差控制在3 mm之内,能够解决由错误选定调姿受力节点造成的机翼壁板承力能力下降的问题,符合实际应用需求。

模型不确定和未知扰动下四旋翼无人机位置与姿态控制

在模型不确定和未知扰动下,针对由六个自由度组成的四旋翼无人机控制问题,提出一种自适应滑模控制方法,该方法能实现位置与姿态跟踪控制。首先,根据四旋翼无人机动力学系统,将其分为全驱动、欠驱动子系统,充分考虑无上下限约束的模型不确定和未知扰动,提炼出各子系统的集合干扰项;然后,借助于径向基函数神经网络对包含集合干扰项的等效控制器进行实时逼近和估计,同时运用自适应控制方法估计逼近误差项,设计带有等效控制器和逼近误差项估计值的滑模控制器和对应的自适应更新律,并根据Lyapunov理论,对各子系统状态轨迹所在滑模面的可达性及其收敛性进行了分析说明;最后,所提方法的有效性通过对比仿真得到了验证。

一种多星分离的姿控联合仿真方法

现阶段仅依据多体动力学,难以准确分析和评估多星分离时含调姿过程的近远场分离过程。因此针对一箭多星任务的分离安全性设计需求,提出了一种姿控联合仿真方法,实现了近远场分离的实时调姿仿真。计算结果表明,该方法与专业弹道软件相比,计算误差不超过5%。同时为了进一步研究结构参数、动力学参数和调姿算法等变量对分离方案的影响,结合拉丁超立方采样和蒙特卡罗打靶法,优化了采样空间,从而可以快速分析变量偏差、采样方式对不同分离工况的影响,进而准确判定分离方案的安全性。该方法实现了参数的自动化设置,可有效提高仿真效率,能为一箭多星发射任务的快速论证及分离安全性设计需求提供有力支撑。

基于多传感器融合的工作面设备定位定姿技术研究

随着科技的发展与进步,煤矿智能化已经成为目前矿业生产中的重点研究方向。但是在薄煤层工作面中由于顶板条件的复杂性以及作业环境的多变性,导致目前的井下自动化控制技术中存在液压支架自动跟机不能完美适应井下顶底板环境且采煤机难以精准定位的问题。以薄煤层工作面自动化控制系统为基础,结合图像识别以及多传感器融合的方法研究采煤机的定位技术,并对液压支架定姿的关键技术进行了分析,期望提高薄煤层自动化系统在煤矿井下的适应性,减少工作面的操作人员,提高煤矿生产的效率。

基于分时策略的离散姿态磁控算法

针对低轨磁控卫星的姿态稳定控制问题,提出了一种基于比例微分算法的分时控制律。与传统的将时间连续控制律离散化的设计思路不同,在控制律设计之初就将系统的测量———执行分时约束纳入考虑,以弱化测量机构与执行机构对系统稳定的不利影响,保证控制系统的精度与稳定性。数学仿真结果表明,该控制律能有效使系统收敛,与经典PID方法相比,在不增加过渡时间的前提下,能够显著提升磁控卫星的姿态精度和稳定度。此外,给出了一种控制律参数的确定方法,该方法可用于确定控制律控制周期、执行机构的工作时间,进而指导执行机构的选型和设计,具有一定的工程应用价值。