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.

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.

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.

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.

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.

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.

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.

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.

基于滑模预测控制的水面无人船轨迹跟踪研究

针对全驱动无人船(USV)的轨迹跟踪问题,提出了一种模型预测控制和积分滑模控制相结合的双层控制方法。首先,针对无人船系统的运动学模型,设计模型预测控制器(MPC)根据期望轨迹得到满足约束条件的期望速度信号;针对动力学模型,设计积分滑模控制器(ISMC)使得系统在外界干扰存在的情况下,实现对期望信号的跟踪,提高了系统的鲁棒性;设计非线性干扰观测器对外界干扰进行估计,并在控制律的设计过程中进行补偿;最后,采用李雅普诺夫方法证明了系统的稳定性。数值仿真证明了两者的结合可以有效地实现全驱动无人船的轨迹跟踪。

Almost Disturbance Decoupling for HOFA Nonlinear Systems with Strict-Feedback Form

The article is devoted to the almost disturbance decoupling problem for high-order fully actuated(HOFA)nonlinear systems with strict-feedback form.Using the full-actuation feature of high-order fully actuated systems and Lyapunov stability theory,a state feedback control law and virtual control laws are designed.The unknown disturbances are handled by almost disturbance decoupling(ADD)method.Finally,the effectiveness of the control strategy is verified by stability analysis and simulation.

时变通信约束下航天器绕飞的高阶全驱预测控制方法

针对视线坐标系下具有时变通信约束的航天器绕飞问题,提出了一种高阶全驱(HOFA)预测控制方法以实现绕飞任务并主动补偿服务航天器与跟踪与数据中继卫星系统间的时变通信延迟和数据丢包。首先,在视线坐标系下引入了一个非线性高阶全驱系统模型来描述航天器绕飞的相对动力学模型,并将所提出的绕飞任务转换为非线性高阶全驱系统的跟踪控制问题。其次,利用全驱特性抵消系统中的非线性,从而构建一个线性高阶全驱(LIHOFA)系统。然后,应用丢番图方程建立一个增量线性高阶全驱预测模型以代替传统的降阶预测模型,进而构建多步超前预测以实现跟踪控制性能的优化和时变通信约束的补偿,从而有效地保证了绕飞任务的实现。同时,给出了一个简单的充要条件以分析闭环系统的稳定性和跟踪性能。最后,还提供了航天器在圆轨道和椭圆轨道绕飞的数值仿真以验证高阶全驱预测控制方法的可行性。