Observer-based robust high-order fully actuated attitude autopilot design for spinning glide-guided projectiles

This paper investigates the design of an attitude autopilot for a dual-channel controlled spinning glideguided projectile(SGGP),addressing model uncertainties and external disturbances.Based on fixed-time stable theory,a disturbance observer with integral sliding mode and adaptive techniques is proposed to mitigate total disturbance effects,irrespective of initial conditions.By introducing an error integral signal,the dynamics of the SGGP are transformed into two separate second-order fully actuated systems.Subsequently,employing the high-order fully actuated approach and a parametric approach,the nonlinear dynamics of the SGGP are recast into a constant linear closed-loop system,ensuring that the projectile's attitude asymptotically tracks the given goal with the desired eigenstructure.Under the proposed composite control framework,the ultimately uniformly bounded stability of the closed-loop system is rigorously demonstrated via the Lyapunov method.Validation of the effectiveness of the proposed attitude autopilot design is provided through extensive numerical simulations.

Optimal Cooperative Secondary Control for Islanded DC Microgrids via a Fully Actuated Approach

DC-DC converter-based multi-bus DC microgrids(MGs) in series have received much attention, where the conflict between voltage recovery and current balancing has been a hot topic. The lack of models that accurately portray the electrical characteristics of actual MGs while is controller design-friendly has kept the issue active. To this end, this paper establishes a large-signal model containing the comprehensive dynamical behavior of the DC MGs based on the theory of high-order fully actuated systems, and proposes distributed optimal control based on this. The proposed secondary control method can achieve the two goals of voltage recovery and current sharing for multi-bus DC MGs. Additionally, the simple structure of the proposed approach is similar to one based on droop control, which allows this control technique to be easily implemented in a variety of modern microgrids with different configurations. In contrast to existing studies, the process of controller design in this paper is closely tied to the actual dynamics of the MGs. It is a prominent feature that enables engineers to customize the performance metrics of the system. In addition, the analysis of the stability of the closed-loop DC microgrid system, as well as the optimality and consensus of current sharing are given. Finally, a scaled-down solar and battery-based microgrid prototype with maximum power point tracking controller is developed in the laboratory to experimentally test the efficacy of the proposed control method.

Adaptive Trajectory Tracking Error Constraint Control of Unmanned Underwater Vehicle Based on a Fully Actuated System Approach

This paper focuses on the trajectory tracking control problem of unmanned underwater vehicles(UUVs)with unknown dead-zone inputs.The primary objective is to design an adaptive trajectory tracking error constraint controller using the fully actuated systems(FAs)approach to enable UUVs to asymptotically track target signals.Firstly,a novel error constraint fully actuated systems(ECFAs)approach is proposed by incorporating the tracking error dependent normalized function and barrier function along with time-varying scaling.Secondly,in order to deal with the model uncertainties of the UUVs,adaptive radial basis function neural networks(RBFNNs)is combined with the ECFAs approach.Then,a positive time-varying integral function is introduced to completely eliminate the effect of the residual effect caused by unknown dead-zone inputs,and it is proved that the trajectory tracking error converges to zero asymptotically based on the Lyapunov functions.Finally,the simulation results demonstrate the effectiveness of the designed adaptive controller.

全驱系统理论在LCL并网逆变器中的控制及应用

利用系统固有的全驱特性可将系统数学模型化为全驱模型,大大简化控制器的设计。文中建立了LCL滤波器全驱系统的数学模型,并推导出其控制率,通过仿真验证了控制的稳定性。

输入受限的挠性航天器全驱姿态饱和控制

面向空间攻防等任务的航天器通常安装微波、激光等大功率对抗载荷,未来航天器需要装备大型挠性太阳能帆板.针对挠性航天器姿态机动过程中存在外部干扰、执行机构饱和及挠性附件振动且挠性模态不易直接测量等问题,提出带挠性附件航天器的全驱姿态控制方法.首先,建立挠性航天器全驱姿态控制模型.其次,基于扩展非线性观测器(Extended nonlinearity observer,ENO)与努斯鲍姆增益调节设计一种抗饱和的姿态控制鲁棒算法.将外部扰动、挠性振动和输入饱和函数饱和估计误差作为复合干扰,采用非线性干扰观测器对其进行有效补偿.在直接参数设计线性控制参数基础上,扩展非线性观测器负责对挠性航天器产生的挠性振动等非线性进行实时估计和补偿,努斯鲍姆函数辅助控制器输出力矩避免饱和,并利用李雅普诺夫方法严格证明闭环系统的稳定性.最后通过数学仿真验证该方法不仅能够实现执行机构饱和约束条件下的姿态控制,还能有效抑制挠性结构的振动,为探索未来带有大型挠性附件航天器姿态控制新的方法提供参考.

基于非线性补偿LQR的全驱动碟式水下机器人控制

本文提出了一种仅使用6个推进器实现全自由度可控的圆碟式水下机器人结构,在静水环境下对其进行动力学建模.随后,基于此模型提出一种带非线性补偿环节的线性二次型调节器(LQR)反馈控制方法,可通过双向水下推进器实现对水下机器人6个自由度的全驱动控制并抑制由重力矩导致的扰动.最后,经仿真试验表明本文设计的非线性补偿算法对重力矩扰动具有很强的抑制作用,控制器能稳定实现水下机器人六自由度状态跟踪,本文中设计的推进器布局也对全驱动水下机器人的设计具有一定的指导意义.

非平面全驱动多旋翼无人机的鲁棒预测控制

针对非平面全驱动多旋翼无人机飞行时易受外部风场与未建模动态影响等问题,设计了鲁棒性较好的预测控制系统。采用牛顿-欧拉法构建了无人机六自由度非线性运动模型;设计了线性扩张状态观测器,将同时受匹配与非匹配干扰影响的无人机系统转化为仅受匹配干扰影响的等效系统,用以估计系统的状态变量;针对等效系统设计预测控制器以降低系统输出振荡和输入激增,设计干扰补偿器以提升闭环系统抗干扰的鲁棒性。仿真实验表明:与常规的非线性动态逆控制方法相比,该算法下的闭环系统具有更强的抗干扰能力与更高的轨迹跟踪精度。

Attitude Control of Spherical Liquid-Filled Spacecraft Based on High-Order Fully Actuated System Approaches

The attitude of spherical liquid-filled spacecraft is controlled based on the high-order fully actuated system approaches.The rigid-fluid coupling dynamic equation can be established in terms of the Euler angles of the spacecraft and the angular velocities of the liquid fuel.According to the dynamic equation,three kinds of input selections are presented.In the case of one control input,the dynamic equation is transformed into the third-order or the second-order differential equations of the Euler angle by the high-order fully actuated system approaches.Then a control law is designed to track the target.The effectiveness of the control law is demonstrated by numerical simulations.

Adaptive Control for a Class of Nonlinear Time-Delay System Based on the Fully Actuated System Approaches

This paper focuses on the problem of adaptive control for a class of time-delay systems.First,the strict feedback nonlinear time-delay system is transformed into a fully actuated system by utilizing the fully actuated system theory.Then,the uncertain time-delay terms of the system are bounded by the product of the absolute value of the system state and the non-linear function with the unknown parameters.By following the high order fully actuated system approaches,a continuous adaptive controller is designed for the system.It is proved that the controller can render the system achieve asymptotically stability.Finally,two numerical examples are provided to illustrate the effectiveness of the theoretical results.

基于全驱系统方法的高阶严反馈系统时变输出约束控制

针对输出受不对称时变约束的不确定高阶严反馈系统,提出一种基于全驱系统方法的高阶自适应动态面输出约束控制方法.所研究的高阶严反馈系统,每个子系统都是高阶形式,通过非线性转换函数将原输出约束系统转换为新的无约束系统,从而将原系统输出约束问题转化为新系统输出有界的问题.进一步结合全驱系统方法和自适应动态面控制,直接将每个高阶子系统作为一个整体进行控制器设计,而不需要将其转化为一阶系统形式,有效简化了设计步骤;同时通过引入一系列低通滤波器来获得虚拟控制律的高阶导数,以代替复杂的微分运算.基于Lyapunov稳定性理论证明闭环系统所有信号是一致最终有界的,系统输出在满足约束的条件下能有效跟踪期望的参考信号,且可通过调整参数使得系统跟踪误差收敛到零附近的足够小的邻域内.最后,通过对柔性关节机械臂系统进行仿真,验证了所提出控制方法的有效性.

Prescribed Error Performance Control for Second-Order Fully Actuated Systems

In this paper,the prescribed error trajectory control is proposed for second-order fully actuated systems.At first,by taking advantage of the full-actuation property,an intermediate control law is designed such that the intermediate closed-loop system is in a very simple form.Then,by utilizing the initial conditions of system states and the prescribed error performance function,the intermediate control law is developed to force the tracking error of the system on the proposed sliding mode surface from the beginning.The overall control law is obtained by combining the aforementioned steps.It is revealed that under the designed control law,the tracking error of the closed-loop system converges to zero along the prescribed error trajectory.Finally,an example is provided to validate the effectiveness of the presented approach.

Fully Actuated System Approach for 6DOF Spacecraft Control Based on Extended State Observer

This paper deals with the problem of position and attitude tracking control for a rigid spacecraft.A fully actuated system(FAS)model for the six degree-of-freedom(6DOF)spacecraft motion is derived first from the state-space model by variable elimination.Considering the uncertainties from external disturbance,unknown motion information,and uncertain inertia properties,an extended state observer(ESO)is designed to estimate the total disturbance.Then,a tracking controller based on FAS approach is designed,and this makes the closed-loop system a constant linear one with an arbitrarily assignable eigenstructure.The solution to the parameter matrices of the observer and controller is given subsequently.It is proved via the Lyapunov stability theory that the observer errors and tracking errors both converge into the neighborhood of the origin.Finally,numerical simulation demonstrates the effectiveness of the proposed controller.

全驱动倾转四旋翼式飞枪的建模与控制

欠驱动的机/枪一体式四旋翼飞枪位置和姿态的控制存在耦合,无法实现带俯仰角的悬停射击,移动射击过程中火控策略复杂。设计了一种全驱动的倾转四旋翼无人机,并以此作为飞枪载体,在实现系统解耦的同时,简化了控制分配方法。首先通过牛顿欧拉法对系统进行数学建模,然后利用反步法设计控制器并证明系统稳定性,最后通过Simulink进行仿真实验。实验结果表明:本文设计的全驱动飞枪模型可实现位置和姿态的解耦控制,跟踪误差小,可满足飞枪悬停射击、移动射击的射击要求,适用于实时性要求高的飞/火控系统。

On the Role of Zeros in the Pole Assignment of Scalar High-Order Fully Actuated Linear Systems

It is well known that for a linear system in state space form,controllability is equivalent to arbitrary pole assignment by state feedback.This brief points out that for a scalar high-order fully actuated linear system,the pole assignment problem is solvable if and only if the desired pole set of the closed-loop system should not include the zero set of the open-loop system if the implementation issue of the controller is taken into account,that is,controllability cannot guarantee arbitrary pole assignment by state feedback.

Predictive Control of High-Order Fully Actuated Nonlinear Systems with Time-Varying Delays

This paper investigates the control problem of high-order fully actuated nonlinear systems with time-varying delays in the discrete-time domain.To make the compensation for time-varying delays concise,active and universal,a novel nonlinear predictive control method is proposed.The designed nonlinear predictive controller can achieve the same expected control performance as the nonlinear systems without delays.At the same time,the necessary and sufficient conditions for the stability of the closed-loop nonlinear predictive control systems are derived.Numerical examples show that the proposed nonlinear predictive controller design method can completely compensate for the time-varying delays of nonlinear systems.

Stabilization via Fully Actuated System Approach:A Case Study

In this note,a benchmark example system which is not stabilizable by a smooth state feedback controller is considered with the fully actuated system(FAS)approach.It is shown that a smooth controller exists which drives the trajectories starting from a large domain in the initial value space to the origin exponentially.Such a result brings about a generalization of Lyapunov asymptotical stability,which is termed as global exponential sub-stability.The region of attraction is allowed to be an unbounded open set of the initial values with closure containing the origin.This sub-stability result may be viewed to be superior to some local stability results in the Lyapunov sense because the region of attraction is much larger than any finite ball containing the origin and meanwhile the feasible trajectories are always driven to the origin exponentially.Based on this sub-stabilization result,globally asymptotically stabilizing controllers for the system can be provided in two general ways,one is through combination with existing globally stabilizing controllers,and the other is by using a pre-controller to first move an initial point which is not within the region of attraction into the region of attraction.

Fully Actuated System Approach for Linear Systems Control:A Frequency-Domain Solution

This note studies fully actuated linear systems in the frequency domain in terms of polynomial matrix description(PMD).For a controllable first-order linear state-space system model,by using the right coprime factorization of its transfer function matrix,under the condition that the denominator matrix in the right coprime factorization is column reduced,it is equivalently transformed into a fully actuated PMD model,whose time-domain expression is just a high-order fully actuated(HOFA)system model.This method is a supplement to the previous one in the time-domain,and reveals a connection between the controllability of the first-order linear state-space system model and the fullactuation of its PMD model.Both continuous-time and discrete-time linear systems are considered.Some numerical examples are worked out to illustrate the effectiveness of the proposed approaches.

Adaptive Neural Network Control of Thermoacoustic Instability in Rijke Tube: A Fully Actuated System Approach

Thermoacoustic instability phenomena often encounter in gas turbine combustors,especially for the premixed combustor design,with many possible detrimental results.As a classical experiment,the Rijke tube is the simplest and the most effective illustration to study the thermoacoustic instability.This paper investigates the active control approach of the thermoacoustic instability in a horizontal Rijke tube.What’s more,the radial basis function(RBF)neural network is adopted to estimate the complex unknown continuous nonlinear heat release rate in the Rijke tube.Then,based on the proposed second-order fully actuated system model,the authors present an adaptive neural network controller to guarantee the flow velocity fluctuation and pressure fluctuation to converge to a small region of the origin.Finally,simulation results demonstrate the feasibility of the design method.

A Fully Actuated System Approach for Stabilization of Discrete-Time Multiple-Input Nonlinear Systems with Distinct Input Delays

In this paper,the problem of stabilization is considered for discrete-time multiple-input nonlinear systems with distinct input delays law based on the fully actuated system approach.In order to compensate the input delays,a prediction scheme is presented to predict future states based on the closed-loop linear system.Then,a stabilizing law is constructed for nonlinear delayed systems by replacing the future states in the control law for the corresponding delay-free systems with their prediction.Finally,numerical examples are given to verify the effectiveness of the proposed approach.

基于扩张状态观测器的非完整系统的镇定控制:一种全驱系统方法

利用全驱系统方法,研究一类具有未知外部扰动的非完整系统的全局镇定控制问题。针对系统的两个控制输入,分别设计指数镇定控制器和基于扩张状态观测器的输出反馈镇定控制器。基于全驱系统模型,通过引入扩张状态观测器来估计系统状态和未知外部扰动。稳定性分析表明,所提出的镇定控制策略能够保证闭环系统的信号是一致有界的。仿真结果验证了所提出的控制方案的有效性和合理性。