自平衡机械系统匀速行走模糊控制

针对自平衡机械系统的研究很少着眼于速度控制,设计一种简单的模糊控制器,应用于一级直线倒立摆的匀速行走控制中.对于设定的速度整定值,通过调整几个比例环节的系数,系统具有很好的动态性能指标,而且控制器在有外界扰动时体现了很好的抗扰能力.考虑到实际物理系统中倒立摆行程的限制,设计的自动切换开关实现了倒立摆在一段给定的行程上匀速来回行走的控制目标,通过手动切换开关也能实现倒立摆的位置控制,因而使得该模糊控制器能完成平衡控制、位置控制、匀速行走控制.经多次试验,给出了比例环节系数大小调整与系统动态性能指标之间关系的大致规律,实验结果验证了该控制器的有效性.     

基于滑模观测器的直线伺服系统反馈线性化速度跟踪控制

在许多高速、高精的直线伺服系统中,要求能实现对速度的快速精确跟踪,但其模型的非线性和变量间的耦合给控制带来难度.对高速、高精速度跟踪控制中,电流和速度的变化过程在时间尺度上相对接近,不能简单地采用磁场定向矢量控制方法实现静态解耦,否则电流和速度间的非线性耦合将破坏速度跟踪品质.采用状态反馈线性化方法来实现永磁直线同步电动机(PMLSM)模型的精确线性化和动态解耦.利用非线性坐标变换和非线性反馈将系统解耦成独立的线性电流子系统和速度子系统.通过扩展滑模观测器来实现对所需要的动子速度、加速度和负载扰动的鲁棒观测.并利用李雅普诺夫理论对由反馈线性化和滑模观测器构成的非线性闭环系统的稳定性进行了证明.仿真结果表明该方案使PMLSM伺服系统具有良好的鲁棒速度跟踪性能.     

一种复杂非线性系统的智能变结构控制方法

采用一种智能结构方法实现复杂非线性系统的控制,给出了设计原则,并用第四代歼击机飞行控制系统设计一个复杂实例来说明方法的有效性,实例系统中包含了两种控制律：增益调参和非线性动态逆控制律,两种控制律都包括了对发动机推力矢量喷管的控制。文中采用了一种基于状态的控制律切换算法进行两类控制律的切换,考虑了变结构系统切换瞬态问题和强迫振荡问题,并给出了简便的解决方法。     

基于MMST分组的一类MIMO非线性系统执行器故障自适应补偿控制

在多输入多输出(Multiple-input multiple-output,MIMO)非线性系统的执行器故障容错控制问题中,控制器能够处理的执行器故障集合的大小与执行器分组方法有很大关系.为扩大系统可处理的执行器故障集合,本文针对一类具有执行器故障的MIMO非线性最小相位系统,提出基于多模型切换(Multiple model switching and tuning,MMST)执行器分组的自适应补偿控制方法.考虑系统的执行器卡死、部分失效和完全失效故障,在微分几何反馈线性化的基础上,研究基于多模型切换的执行器分组切换指标和切换策略,设计了基于反演控制的自适应补偿跟踪控制律,所设计的控制律能保证系统在执行器故障时闭环稳定,渐近跟踪给定的参考信号,且提出的分组方法扩大了可补偿的执行器故障集合.仿真结果表明了本文设计方法的有效性.     

电力系统非线性切换励磁控制

针对反馈线性化方法难以同时提高电力系统的功角稳定性和电压调节特性的问题,提出了基于分层设计思想的非线性切换励磁控制方法.首先采用逆系统方法实现了系统的反馈线性化,然后根据Lyapunov函数方法对包含零动态的部分线性化系统设计了切换励磁控制器.在电力系统专用仿真平台上的仿真结果证明了所设计的切换控制器能够有效改善功角稳...     

自平衡机械系统匀速行走模糊控制

针对自平衡机械系统的研究很少着眼于速度控制,设计一种简单的模糊控制器,应用于一级直线倒立摆的匀速行走控制中。对于设定的速度整定值,通过调整几个比例环节的系数,系统具有很好的动态性能指标,而且控制器在有外界扰动时体现了很好的抗扰能力。考虑到实际物理系统中倒立摆行程的限制,设计的自动切换开关实现了倒立摆在一段给定的行程上匀速来回行走的控制目标,通过手动切换开关也能实现倒立摆的位置控制,因而使得该模糊控制器能完成平衡控制、位置控制、匀速行走控制。经多次试验,给出了比例环节系数大小调整与系统动态性能指标之间关系的大致规律,实验结果验证了该控制器的有效性。     

超磁致伸缩微致动器车削加工系统模糊自适应精密位移控制

考虑温度及弹簧非线性的影响,基于非线性压磁理论、扩展的J-A模型及动力学分析,建立超磁致伸缩微致动器车削加工系统非线性动力学模型;研究了前馈径向基函数(RBF)逆控制与多模自适应反馈控制方法.提出了以系统运行时间为开关的多模切换控制方案,在系统初始运行时刻采用PD反馈控制器,当时间达到规定的切换时刻采用自适应模糊滑模反馈控制器,使系统全局具有较高的跟踪精度.     

高阶不确定非线性系统线性状态反馈自适应控制设计

研究了一类控制系数未知的高阶不确定非线性系统的自适应镇定控制设计. 尽管该问题已经得到解决,但是所设计的控制器是非线性反馈形式,较为复杂. 与现有文献不同,本文通过综合运用增加幂积分技术和切换自适应控制方法,给出了该控制问题的更为简单且易于实现的新型线性反馈控制器,使得系统状态有界且最终趋于零. 值得指出的是,与切换自适应控制文献相比,本文所研究的非线性系统具有更严重的不确定/未知性和更强的非线性,这主要体现在未知的系统控制系数和更高的系统幂次中.     

基于Simulink仿真的步进电机闭环控制系统分析

步进电机通常以开环方式应用于精度要求不高的位置伺服系统中.通过位置反馈,可以实现步进电机的高精度闭环定位控制.建立的步进电机数学模型,显示了其高度非线性的特点,为此设计了应用于步进电机闭环控制的参数模糊自整定PID控制器.通过Simulink仿真,分别分析了PID控制、模糊PID控制在步进电机跟踪给定位置时系统的响应情况.并通过分析转速输出曲线,提出了加入模糊速度前馈控制环的系统改进方案,系统稳定性得到较大提高.     

自主式智能体有限时间停车问题及控制策略设计

提出自主式智能体在有限时间内的停车控制问题.基于极坐标系下自主式智能体的非线性运动模型,将智能体运动控制系统分解为原地转动的线性系统和直线运动、转动结合的弱非线性系统两种形式.利用 Lyapunov 设计方法,得到在有限时间内智能体到达给定停车区域的切换控制律,并给出到达给定区域所需时间的估算公式.仿真算例表明了所提出控制方法的有效性.     

High-gain feedback in non-linear control systems†

High-gain state and output feedback are investigated for non-linear control systems with a single additive input by using singular perturbation techniques.

Classical approximation results (Tihonov-like theorems) in singular perturbation theory are extended to non-linear control systems by defining a composite additive control strategy, a control-dependent fast equilibrium manifold and non-linear change of coordinates.

Those tools and an appropriate change of coordinates show that high-gain state feedback and variable structure control systems can be equivalently used for approximate non-linearity compensation in feedback-linearizable systems.

Next the effect of high-gain output feedback is shown to be related to the strong invertibility property and the relative order of invertibility. For strongly invertible systems the slow reduced subsystem coincides with the dynamics of the inverse system when zero input is applied and with the unobservable dynamics when a certain input-output feedback-linearizable transformation is applied.     

Linear and non-linear skyhook damping control laws for active railway suspensions

This paper presents and compares different control strategies for applying “skyhook” damping control laws in active suspension systems for railway vehicles. It first examines a number of linear approaches for filtering the absolute velocity signal in order to optimise the trade-off between the random and deterministic track input requirements, and then what can be achieved using non-linear methods based upon Kalman-filters is explored. The principles that are developed are general and can be applied to both vertical and lateral secondary suspensions, although the paper concentrates upon the vertical direction and quantifies the performance achievable for a particular combination of track characteristics.     

Nonlinear regulation in constrained input discrete-time linear systems

The use of composite linear and non-linear feedback laws for the control of constrained input discrete-time linear systems is re-examined. By making use of the delta operator formulation of a discrete-time system, an apparent restriction on the magnitude of the non-linear control law is removed, and the similarities between the continuous and discrete-time solutions to the problem are elucidated. In order to develop the results, unconstrained systems are treated initially, but it is shown that, locally, the sufficient conditions for the stabilization of such systems are actually equivalent to those for the stabilization of the corresponding constrained systems.     

Decentralized Adaptive Control of Interconnected Non-Linear Systems Using High Gain Observer

This paper investigates a decentralized adaptive control strategy for a class of interconnected unknown non-linear systems. The idea of the strategy is based on the feedback linearizing control and perturbation estimation. A high gain observer is designed in association with each sub-system to estimate the states and a fictitious state which is defined to represent the system perturbation including the combined effect of system non-linearities, unknown system dynamics, disturbances and interactions between sub-systems. Subject to the availability of sub-system states, two local controllers — decentralized non-linear adaptive state-feedback controller (DNASFC) and decentralized non-linear adaptive output-feedback controller (DNAOFC) — are developed using a high gain perturbation observer (HGPO) or a high gain state and perturbation observer (HGSPO) respectively. The stability and error analysis of the high gain observers and the closed-loop control systems are addressed in detail. The two proposed controllers are evaluated on an interconnected non-linear system involving two inverted pendulums on carts without velocity measurements.     

Local separation principle for non-linear systems

In this paper, we consider the problem of locally stabilizing non-linear systems by output feedback control. To be precise, the separation principle for non-linear systems are studied, which allows the design of the control law and the observer to be carried out independently. While the previous results assumed the existence of Lyapunov function for the observation error, we assume the existence of a state observer which asymptotically estimates the true state. As a matter of fact, it turns out that the latter condition is necessary for the former condition, but the converse is not true. The separation principle with the reduced order observer is also presented. Under the assumption that a non-linear system has asymptotically stable zero dynamics and is locally detectable, it is shown that the asymptotic output tracking by output feedback control can be achieved.     

Longitudinal tunnel ventilation control. Part 1: Modelling and dynamic feedforward control

Road tunnels exceeding a certain minimum length are equipped with a ventilation system. In case of a fire it is used to achieve a predefined air flow velocity in the tunnel by adequately controlling the installed jet fans in order to ensure sufficient visibility for persons to safely follow the escape routes. As the dynamics of the air flow in road tunnels strongly depend on the tunnel length, short tunnels with longitudinal ventilation systems pose a challenging control task. In this paper, non-linear dynamic feedforward control is proposed for longitudinal ventilation control in case of an emergency. For this purpose, an analytical non-linear zero-dimensional model of the air flow is feedback linearised. Due to its special properties, which are presented and analysed, two different versions of feedforward control are proposed: One is focused on performance, the other on robustness. Finally, the beneficial behaviour of the presented two-degrees-of-freedom control approach is demonstrated by its application to an Austrian motorway tunnel.     

Observer and global output feedback stabilisation for some mechanical systems

The objective of the work is two-fold. A first part is devoted to the problem of constructing an observer to the practical system called overhead crane with the position as output. In a second part, the problem of global output feedback stabilisation is solved for a class of Euler–Lagrange systems when the variables of velocity are the unmeasured part of the state. The equations of these systems are non-linear with respect to the velocities. A new output feedback control scheme is proposed. It relies on the determination of a change of coordinates which gives to the systems a triangular form. To illustrate the approach, it is applied to a two-link manipulator.     

Exponential tracking of feedback linearizable non-linear control systems with uncertainties

This paper studies the robust output tracking problem of feedback linearizable non-linear control systems with uncertainties. Utilizing the input-output feedback linearization technique and the Lyapunov method for non-linear state feedback synthesis, a robust globally exponential output tracking controller design methodology for a broad class of non-linear control systems with uncertainties is developed. The underlying theoretical approaches are the differential geometry approach and the composite Lyapunov approach. One utilizes the parametrized coordinate transformation to transform the original non-linear system with uncertainties into a singularly perturbed model with uncertainties and the composite Lyapunov approach is then applied for output tracking. To demonstrate the practical applicability, the paper has investigated a pendulum control system.     

Non-linear output feedback stabilization on a bounded region of attraction

In this paper it is shown that, for multi-input single-output non-affine non-linear systems, when a state feedback control stabilizes an equilibrium point of a plant with a certain bounded region of attraction, it is also stabilized by an output feedback controller with arbitrarily small loss of the region. Moreover, the proposed output feedback controller has the dynamic order n which is the same as the order of the plant. From any given state feedback, an explicit form of the overall controller is provided. A sufficient condition presented for the result is shown to be necessary and sufficient for regional uniform observability when the system is input affine. Thus, the result can be regarded as a regional separation principle for affine non-linear systems.     

单片机控制的负阻自激振动系统

振动式输送机是采用惯性激振器控制的机械振动系统,可以利用共振达到高效节能的目的。为了提高共振机械的运动稳定性,我们采用振动速度倒向信号的闭环反馈,利用微机控制技术实现了自动频率跟踪的平稳共振状态。