论时间导数的观察者

本文从物质导数的定义出发,对质点物质导数的观察者提出与文献[1]不同的看法,并由此展开对质点时间导数的物理含意的分析与论证。     

Output regulation boundary control of first-order coupled linear MIMO hyperbolic PIDE systems

ABSTRACT

The work addresses the output regulation problem for coupled linear multiple input multiple output (MIMO) hyperbolic partial integro-differential equation systems with disturbances affecting the systems through the space and boundary input. The exosystems are extended to generate ramp signals and general family of polynomial signals. The system decomposition is applied through the state transformation and yields a decoupled equivalent system. Based on the decoupled form, the backstepping transformation is applied and then in the new coordinate, the full state and output-feedback regulators are designed, respectively. For the state feedback regulator, the corresponding regulator equation is obtained and its solvability conditions are provided to facilitate the regulator design and feasibility. The design of observer-based regulator is based on the decoupling of the observer error system into a PDE subsystem and an ODE subsystem so that the backstepping approach achieves stabilisation by eigenvalue assignment leading to design of observer stabilizing gains.     

An approach to improve active disturbance rejection control

ABSTRACT

In order to reduce the error and phase delay of the classical extended state observer (ESO) in estimating the system state and disturbance, in this paper, we combine ESO and tracking differentiator (TD) to construct a tracking differential extended state observer (TDESO). The observation error and observation speed of TDESO are also discussed. Then a nonlinear active disturbance rejection control system improved by TDESO for a linear plant is transformed into a Lurie system. Moreover, the circular criterion is used to analyse the absolute stability of the transformed Lurie system. Finally, TDESO is optimised and an improved linear state error feedback (PLSEF) is proposed to improve the rapidity of the system by using simulation and time domain analysis. And a second-order system is used to illustrate the performance of the proposed scheme. The simulation results show that our algorithm is effective.     

一阶线性自抗扰控制的整定

线性自抗扰控制（linear active disturbance rejection control,LADRC）是解决系统外部不可测扰动和内部未知不确定性的一种新型控制方法。其精髓是将系统的不确定性转化为一个可观测的状态,利用扩张状态观测器进行实时估计,并用状态反馈控制率实时进行补偿。在满足鲁棒度策略和时间乘平方误差积分的约束条件下,首先针对一阶惯性加迟延模型提出了一阶LADRC的整定公式,然后通过典型的基准系统和温度控制实验,对整定公式进行测试,最后与常规的SIMC （simplified internal model control）-PI （proportional-integral）整定方法进行性能比较。仿真结果证明了该一阶LADRC整定公式的可行性,拓展了其在工业控制领域的应用。     

新趋近律的直流微电网母线电压滑模控制设计

随着直流微电网技术的快速发展,直流微电网中母线电压的稳定性控制作为直流微电网正常平稳运行的关键,也成为了研究热点之一;针对直流微电网母线电压外环易受参数摄动和负荷扰动的影响,提出了一种扩张状态扰动观测器ESO(Extend state observer)与新型趋近律的滑模控制器NRSMC(New reaching law sliding mode control)相结合的复合控制器ESO-NRSMC;该控制器采用了一种新型趋近律方法来解决抖振现象与滑模面趋近时间之间的矛盾;同时扩张状态观测器将观测到的扰动值补偿到滑模控制器中,进一步提高控制器的抗扰动能力;还构造了Lyapunov函数来验证所设计的母线电压外环闭环控制系统的稳定性;最后通过仿真证明控制器ESO-NRSMC在微电网系统参数发生变化以及负载扰动的情况下,依然能够实现对直流微电网母线电压的稳定控制,具有较强的优越性和鲁棒性能。     

Distributed Fault-Tolerant Consensus Tracking of Multi-Agent Systems Under Cyber-Attacks

This paper investigates the distributed fault-tolerant consensus tracking problem of nonlinear multi-agent systems with general incipient and abrupt time-varying actuator faults under cyber-attacks. First, a decentralized unknown input observer is established to estimate relative states and actuator faults. Second, the estimated and output neighboring information is combined with distributed fault-tolerant consensus tracking controllers. Criteria of reaching leader-following exponential consensus tracking of multi-agent systems under both connectivity-maintained and connectivity-mixed attacks are derived with average dwelling time, attack frequency, and attack activation rate technique, respectively. Simulation example verifies the effectiveness of the fault-tolerant consensus tracking algorithm.      

基于滑动窗实时小波降噪的扩张状态观测器及自抗扰控制EI北大核心CSCD

自抗扰控制技术应用已日渐成熟,但当系统中存在高频非平稳噪声信号时,线性自抗扰控制(LADRC)存在难以选取合适的观测器带宽的问题:当带宽较小时,线性扩张状态观测器(LESO)难以实现对总扰动的实时观测,会造成时滞;当带宽较大时,LESO又会放大噪声对系统的影响,从而造成总扰动观测失真.为了解决这一问题,将小波降噪环节加入LADRC中,通过设计基于滑动窗实时小波降噪的LESO,对含噪输出信号进行实时降噪.使用Simulink搭建系统模型,分别在输出信号中加入高斯白噪声或谐波等不同类型的高频非平稳噪声进行仿真实验,并将所提方法与滑动平均法进行对比,结果验证了所提方法的有效性.     

一种带时间协同和角度约束的多导弹三维协同制导律

针对多枚导弹在三维空间从不同初始位置同时拦截机动目标的问题,设计了一种带视线角约束的有限时间协同制导律.首先,给出三维空间的导弹–目标相对运动方程并建立了考虑视线角约束的多弹协同制导模型.其次,对视线纵向及法向方向分别设计了相应的协同制导律.其中在视线方向基于多智能体有限时间一致性理论设计了协同制导律,保证各拦截弹能够同时击中目标;基于一种新型的固定时间非奇异终端滑模控制方法设计了视线法向上的角度约束制导律,使各拦截弹的视线角能够在固定时间内收敛至期望值,实现空间上的协同;同时,构造了扩张状态观测器估计目标加速度.最后,对三枚导弹同时拦截同一机动目标的情况进行仿真对比,验证了本文所提出协同制导律的有效性.     

可穿戴五自由度上肢外骨骼机器人固定时间控制

针对可穿戴上肢外骨骼系统在外部干扰及参数不确定条件下的轨迹跟踪问题,提出了一种基于观测器的固定时间控制策略.首先,采用拉格朗日方法对五自由度上肢外骨骼系统的动力学模型进行面向控制处理.其次,考虑模型中存在参数不确定及外部干扰,基于改进超螺旋算法设计了固定时间干扰观测器,实现对系统干扰的实时估计,完成对控制器的在线补偿;在此基础上,设计了非奇异终端滑模固定时间控制律,保证外骨骼关节角度跟踪误差在固定时间内收敛至原点.再次,基于Lyapunov方法证明了闭环系统的稳定性.最后,通过对比和数值仿真结果证明所提出控制策略的有效性.     

DoS攻击下基于切换Luenberger观测器的冗余控制

研究了DoS攻击下网络化控制系统基于观测器的控制器设计问题.首先,提出了一种具有多个增益的切换Luenberger观测器,实现了无DoS攻击时系统状态的间歇性估计.根据获得的估计值,控制器同时计算了系统当前以及未来一段时域的控制信号,并将其封装在一个数据包中发送给执行器,保证了系统在有无DoS攻击时都有合适的控制输入更新.其次,利用构造的切换系统对DoS攻击下观测器与控制器的不同动态进行了统一的建模,基于多Lyapunov函数方法推导了任意切换律下系统指数稳定的充分条件,并给出了相应的观测器与控制器设计方法.最后,通过网络化倒立摆系统的实验验证了所提方法的有效性.