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。     

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.     

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.     

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.     

Adaptive output-feedback control for a class of nonlinear systems with actuator failures and input quantisation

In this paper, an adaptive output feedback control technique is proposed for a class of nonlinear systems with unknown parameters, unknown nonlinear functions, quantised input and possible actuator failures up to infinity. A modified backstepping approach is proposed by the use of high-gain K-filters, hyperbolic tangent function property and bound-estimation approach to compensate for the effect of possible number of actuator failures up to infinity, input quantisation and unknown nonlinear functions. It is proved both mathematically and by simulation that with the proposed controller, all the signals of the closed-loop system are globally bounded despite of input quantisation, unknown nonlinear functions and possible number of actuator failures up to infinity.     

Placement optimization of actuator and sensor and decentralized adaptive fuzzy vibration control for large space intelligent truss structure

Large space truss structure is widely used in spacecrafts.The vibration of this kind of structure will cause some serious problems.For instance,it will disturb the work of the payloads which are supported on the truss,even worse,it will deactivate the spacecrafts.Therefore,it is highly in need of executing vibration control for large space truss structure.Large space intelligent truss system(LSITS) is not a normal truss structure but a complex truss system consisting of common rods and active rods,and there...     

Adaptive output feedback tracking control for a class of uncertain switched nonlinear systems under arbitrary switching

This paper investigates the problem of adaptive output feedback tracking for uncertain switched nonlinear systems, under arbitrary switching. First, an adaptive output feedback controller is designed, which ensures the boundedness of all the closed-loop signals. Then, a novel adaptive-based robust output feedback control is proposed to drive the tracking error to zero, in which the bound of disturbances is not required to be known in advance. Both control algorithms are based on the common Lyapunov function method, without any restrictions on dwell time. To evaluate the performance of the proposed output feedback control schemes, a numerical example is presented and discussed.     

A self-organizing fuzzy logic controller for the active control of flexible structures using piezoelectric actuators

This paper proposes an on-line self-organizing fuzzy logic controller (FLC) design applied to the control of vibrations in flexible structures containing distributed piezoelectric actuator patches. In this methodology, the fuzzy rules are generated using the history of input/output (I/O) pairs without using any plant model. The generated rules are stored in the fuzzy rule space and updated on-line by a self-organizing procedure. The validity of the proposed fuzzy logic control has been demonstrated experimentally in a steel cantilever test beam and a set of experimental tests are made in the system to verify the efficiency of the on-line self-organizing fuzzy controller.     

Digital control of an electromagnetic suspension system using the TMS-32020 signal processor

Dynamics and control of electromagnetic suspension (EMS) systems for noncontacting vehicle suspension have been extensively studied during past two decades. Due to the inherent nonlinearities and open-loop instability of the EMS system, excitation control of vehicle suspension electromagnets is accomplished either through precision analogue controllers or by using large on-board computer systems. Drift and inflexibility are design constraints of the former, while the latter has significant capital costs. With the availability of low-cost, high-speed and wide data-byte VLSI devices, use of digital techniques to control high-speed analogue systems is now becoming feasible. This paper establishes a framework for the real-time control of this unstable nonlinear EMS system using the Texas Instruments TMS-32020 digital signal processor (DSP).     

Cascade cavity realization for a class of complex transfer functions arising in coherent quantum feedback control

This paper presents a realization algorithm for a class of complex transfer function matrices corresponding to physically realizable linear quantum systems. The aim of the realization algorithm is to enable a coherent quantum feedback controller, which has been synthesized using methods such as quantum H^∞ control or quantum LQG control, to be constructed using optical components such as cavities and phase-shifters. The class of linear quantum systems under consideration are passive linear quantum systems which can be described purely in terms of annihilation operators. The proposed algorithm enables a complex transfer function matrix to be realized as a pure cascade connection involving only cavities and phase-shifters.     

The switching algorithm for the control of overhead crane

This paper presents the fuzzy logic based method to control the trolley cranes. The information, including the position of trolley, load swing and the differences between the present and previous signals, are applied to derive the proper power to drive the trolley. An easy but effective switching algorithm is investigated to improve the control of trolley and suppress the load swing in this paper. This also helps to enhance the control power of the crane to depart from the deadzone. Finally, several experiments through the scaled trolley crane demonstrate the effectiveness of the scheme.This work was supported by the National Science Council of the Republic of China under Grant NSC-91-2213-E-231-007.