智能电动执行器

智能电动执行器将微机技术直接与电动执行器结合起来,克服了传统产品的不足,提高了技术指标,并增加了功能。本文介绍了智能电动执行器的工作原理、结构及技术特点。     

简化电动执行器的控制

传统的电动机执行器控制由组合仪表构成 ,系统复杂、故障率高、造价较高。而今PLC的使用越来越普遍 ,在控制装置已有PLC配置的基础上 ,利用剩余的几个I/O点和元件即可构成简单、可靠、性能优良而又美观的电动执行器控制系统。     

集中供电的电动执行器用位置发送器

介绍一种采用直流２４Ｖ集中供电的新型位置发送器。详细介绍了该位置发送器的方案、组成和工作原理,文末给出整机测试结果。     

电动执行器故障诊断的研究

以往对于执行器的故障诊断主要基于仿真层面,然而在实际应用中却不太理想.针对上述情况,通过深入分析执行器的故障特点提出了一些切实可行的诊断方法以及排除故障的方法.这些方法不需要建立执行器复杂的数学模型,而是通过分析输入信号和输出信号变化特点进行故障诊断,具有运算简单、判断迅速、成本低等优点.这些排除故障的方法,只要采集适当的信号就可以实现故障诊断适用于电动执行器及其他类型的执行器.     

基于MODBUS的电动执行器远程控制系统实现

介绍了基于MODBUS的智能通讯模块的硬件与软件设计。模块采用通用的MODBUS通讯接口以及有效的保护电路,并组建了电动执行器的远程控制系统,实现了电动执行器的智能化集中管理。系统具有高可靠、操作简便、性能价格比高等优点。     

基于AVR单片机的电动执行器控制模块检测仪的设计

电动执行器控制模块采用传统的控制电路结构较复杂,发生故障的概率相对较高,另外,电机在运行时会产生很多热量,导致电机发热过高,增加了机械的磨损,结果造成执行器运行速度慢,耗费时间,寿命短。本文采用一种基于AVR单片机ATMEGA329为核心的电动执行器控制模块检测仪,很好的解决了传统电动执行器控制模块存在的问题,实现了较高的可靠性和稳定性,可以长距离的传输信号,且速度较快,与其它一些仪表可以做到调试、功能和技术性能测试。文中简介了该控制模块检测仪的基本原理、设计方案和实验测试结果。最后经过试验证明,该电动执行器运行稳定,可靠,能够满足技术更新的要求。     

电动执行机构常见故障及快速排除方法

简要介绍了电动执行机构的定义、分类及其工作原理,着重分析了执行机构的常见故障及其排除方法。     

基于神经网络的电动执行器状态诊断

本文以神经网络为工具,以电动执行器为研究对象,提出基于自组织竞争型神经网络的电动执行器诊断方法,利用该网络的非线性动态系统辨识能力,通过比较系统预测值和实际参数测量值,达到状态诊断的目的。本系统以VB6.0为开发工具,以SQLServer2000为后台数据库,实现了对电动执行器的智能状态诊断。     

基于神经网络的电动执行器状态诊断

本文以神经网络为工具,以电动执行器为研究对象,提出基于自组织竞争型神经网络的电动执行器诊断方法,利用该网络的非线性动态系统辨识能力,通过比较系统预测值和实际参数测量值,达到状态诊断的目的.本系统以VB6.0为开发工具,以SQL Server2000为后台数据库,实现了对电动执行器的智能状态诊断.     

基于DeviceNet现场总线的电动执行器控制系统开发

介绍了具有DeviceNet现场总线通信接口的电动执行器的开发过程。保留了原有电动执行器现场控制功能,增加了DeviceNet远程控制和故障信号的采集。给出了软硬件实现方案和程序流程图,并详细讨论了DeviceNet对象模型的建立和在Keil C中对象化的实现方法。该电动执行器支持组态软件的接入并实现与其他DeviceNet现场总线产品的互连、互操作。     

Stabilisation and control synthesis of switching systems subject to actuator saturation

This article presents sufficient conditions for the stabilisation of switching discrete-time linear systems subject to actuator saturations. These conditions are obtained by using successively state and output feedback control laws. The obtained results are formulated in terms of linear matrix inequalities (LMIs). The saturating and non-saturating controllers are synthesised for both cases in this work. Three sets of LMIs are presented for output feedback case. Numerical examples are used to illustrate these techniques by using a linear optimisation problem subject to LMI constraints.     

Fault-tolerant control of linear systems using adaptive virtual actuator

In this paper, design and development of fault-tolerant control (FTC) is investigated for linear systems subject to loss of effectiveness and time-varying additive actuator faults as well as an external disturbance using the fault-hiding approach. The main aim of this approach is to keep the nominal controller and to design a virtual actuator that is inserted between the faulty plant and the nominal controller in order to hide actuator faults and disturbances from the nominal controller, and consequently the performance of the system before and after the occurrence of actuator faults is kept to be the same. The proposed adaptive virtual actuator does not require a separated fault detection, isolation and identification (FDII) unit and both state and output feedback cases are considered. An illustrative example is given to demonstrate the effectiveness of the proposed adaptive virtual actuator in both cases.     

Precise control of linear systems subject to actuator saturation using tracking differentiator and reduced order composite nonlinear feedback control

Aiming at the actuator saturation problem and the system performance requirement, this article proposes a new control scheme, i.e. a newly developed tracking differentiator-composite nonlinear feedback (TDCNF) control law, which is the combination of a tracking differentiator (TD) and a reduced order composite nonlinear feedback (CNF) control law. The TD, used here, mainly helps to provide a smooth reference signal and largely avoid actuator saturation. The reduced order CNF control law, on the one hand, estimates those unmeasurable state variables for measurement feedback control and, on the other hand, ensures satisfactory system performance. The stability of the newly developed TDCNF is proved in detail. Finally, to verify the effectiveness of the newly developed TDCNF control law, two illustrative examples are demonstrated and therein a novel design of the proposed control law is given. Simulation results show that the proposed control law can achieve good tracking performance and effectively avoid the actuator saturation.     

压电陶瓷执行器的非光滑三明治模型辨识与内模控制

压电陶瓷执行器中含有非光滑、多值映射、频率依赖的非线性迟滞特性,然而在实际应用中,压电器件的输入输出信号无法直接测量,常规方法难以进行有效的辨识和控制.本文采用三明治模型来精确描述实际对象,并提出一种基于退化激励信号的两步辨识法解决三明治迟滞模型的辨识问题.最后,基于已辨识的三明治模型,设计一个内模控制器,解决压电陶瓷执行器的精密轨迹控制问题.实验结果表明所提出的辨识和控制方案取得了令人满意的结果.     

Simultaneous optimization of photostrictive actuator locations,numbers and light intensities for structural shape control using hierarchical genetic algorithm

The present paper introduces an investigation into simultaneous optimization of the PbLaZrTi-based actuator configuration and corresponding applied light intensity for morphing beam structural shapes. A finite element formulation for multiphysics analysis of coupled opto-electro-thermo-mechanical fields in PbLaZrTi ceramics is derived and verified with the theoretical solution and the commercial software ANSYS. This element is then used to simulate beam bending shape control using the orthotropic PbLaZrTi actuators and the simultaneous optimization. In this procedure, the controlling and geometrical variables are simultaneously optimized via a hierarchical genetic algorithm. A bi-coded chromosome is proposed in a hierarchical mode, which consists of some control genes (i.e. actuator location and number) and parametric genes (i.e. applied light intensity). Whether the parametric gene is activated or not is managed by the value of the first-grade control genes. The numerical results demonstrate that the achieved beam bending shapes correlate remarkably well with the expected ones and the simultaneous optimization of photostrictive actuator locations, numbers and light intensities can result in optimal actuator layout with less PbLaZrTi actuators and irradiated light energy. The simulation results also show that the hierarchical genetic algorithm has more superior performance over the conventional real-coded genetic algorithm.     

Position control of electro-hydraulic actuator system using fuzzy logic controller optimized by particle swarm optimization

The position control system of an electro-hydraulic actuator system (EHAS) is investigated in this paper. The EHAS is developed by taking into consideration the nonlinearities of the system: the friction and the internal leakage. A variable load that simulates a realistic load in robotic excavator is taken as the trajectory reference. A method of control strategy that is implemented by employing a fuzzy logic controller (FLC) whose parameters are optimized using particle swarm optimization (PSO) is proposed. The scaling factors of the fuzzy inference system are tuned to obtain the optimal values which yield the best system performance. The simulation results show that the FLC is able to track the trajectory reference accurately for a range of values of orifice opening. Beyond that range, the orifice opening may introduce chattering, which the FLC alone is not sufficient to overcome. The PSO optimized FLC can reduce the chattering significantly. This result justifies the implementation of the proposed method in position control of EHAS.     

Extremum seeking control for soft landing of an electromechanical valve actuator

Many electromagnetic actuators suffer from high velocity impacts. One such actuator is the electromechanical valve actuator, recently receiving attention for enabling variable valve timing in internal combustion engines. Impacts experienced by the actuator are excessively loud and create unnecessary wear. This paper presents an extremum seeking controller designed to reduce the magnitude of these impacts. Based on a measure of the sound intensity at impact, the controller tunes a nonlinear feedback to achieve impact velocities of less than while maintaining transition times of less than . The control strategy is implemented with an eddy current sensor, to measure the valve position, and a microphone.     

非线性奇异系统非交互控制的反馈实现

研究非线性奇异系统的非交互控制的反馈实现问题．首先给出了非线性奇异系统的向量相对阶与其非交互控制实现的关系；然后对正则非线性奇异系统的反馈控制系统的非交互控制的实现问题，给出了一种可使系统实现非交互控制的反馈律的构造方法。     

Construction of switching sequences for reachability realization of switched impulsive control systems

This paper studies the construction of switching sequences for reachability realization of switched impulsive control systems. An approach is proposed to design switching sequences so that the reachable subspace of switched impulsive control systems is expressed in terms of the reachable state sets of the designed switching sequences. For a class of switched impulsive control systems, it is proved that a single switching sequence can be designed with its reachable state set coinciding with the reachable subspace. Periodic switching sequences are also constructed in this paper for the reachability realization problem. The results present a new way to exploit the switching mechanism to achieve the reachability and controllability of switched impulsive control systems. Copyright © 2007 John Wiley & Sons, Ltd.     

Structural design of composite nonlinear feedback control for linear systems with actuator constraint

The performance of the composite nonlinear feedback (CNF) control law relies on the selection of the linear feedback gain and the nonlinear function. However, it is a tough task to select an appropriate linear feedback gain and appropriate parameters of the nonlinear function because the general design procedure of CNF control just gives some simple guidelines for the selections. This paper proposes an operational design procedure based on the structural decomposition of the linear systems with input saturation. The linear feedback gain is constructed by two linear gains which are designed independently to stabilize the unstable zero dynamics part and the pure integration part of the system respectively. By investigating the influence of these two linear gains on transient performance, it is flexible and efficient to design a satisfactory linear feedback gain for the CNF control law. Moreover, the parameters of the nonlinear function are tuned automatically by solving a minimization problem. The proposed design procedure is illustrated by applying it to design a tracking control law for the inverted pendulum on a cart system. Copyright © 2010 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society