High-performance robust motion control of machine tools: an adaptive robust control approach and comparative experiments

This paper studies the high-performance robust motion control of machine tools. The newly proposed adaptive robust control (ARC) is applied to make the resulting closed-loop system robust to model uncertainties, instead of the disturbance observer (DOB) design previously tested by many researchers. Compared to DOB, the proposed ARC has a better tracking performance and transient in the presence of discontinuous disturbances, such as Coulomb friction, and it is of a lower order. As a result, time-consuming and costly rigorous friction identification and compensation is alleviated, and overall tracking performance is improved. The ARC design can also handle large parameter variations and is flexible in introducing extra nonlinear robust control terms and parameter adaptations to further improve the transient response and tracking performance. An anti-integration windup mechanism is inherently built in the ARC and, thus, the problem of control saturation is alleviated. Extensive comparative experimental tests are performed, and the results show the improved performance of the proposed ARC.     

Variable-structure direct torque control - a class of fast and robust controllers for induction machine drives

A family of variable-structure controllers for induction machine drives is presented, in which the principles of direct torque control (DTC), variable-structure control (VSC), and space-vector pulsewidth modulation are combined to ensure high-performance operation, both in the steady state and under transient conditions. Three new VSC schemes are designed following the DTC voltage-control-based philosophy. These provide robust, fast, and accurate torque and flux control, without the penalty of high chattering. Comparative results demonstrate that proposed techniques preserve the DTC transient merits, while the steady-state behavior is significantly improved. Experimental results prove the strong robustness, accuracy, quickness, and low-ripple sensor-less operation of a drive that uses the new schemes.     

Predictive direct torque control for the PM synchronous machine

This paper shows that a predictive digital control combined with the principle of direct torque control (DTC) leads to an excellent dynamic behavior of the synchronous machine with surface-mounted permanent magnets and is a real alternative to the classical field-orientated control. The advantages are a DTC control scheme with constant switching frequency and a predictable torque ripple. The settling times of the torque are reduced compared to the classical field-orientated control. The application in servo drives in which the rotor position is always measured can easily be achieved by using a commercial digital signal processor. Numerous simulations and measurements confirm the theoretical work.     

Nonlinear adaptive torque control of electro-hydraulic load system with external active motion disturbance

This paper develops a high performance nonlinear adaptive control method for electro-hydraulic load simulator (EHLS). The tracking performance of EHLS is mainly affected by the following factors: actuator’s active motion disturbance, flow nonlinear and parametric uncertainties, etc. Most previous studies on EHLS pay too much attention on actuator’s active motion disturbance, while deemphasize the other two factors. This paper concerns EHLS as a motion loading system. Besides actuator’s motion disturbance, both the nonlinear characteristics and parametric uncertainties of the loading system are addressed by the present controller. First, the nonlinear model of EHLS is developed, and then a Lyapunov-based control algorithm augmented with parameters update law is developed using back-stepping design method. The stability of the developed control algorithm is proven via Lyapunov analysis. Both the co-simulation and experiment are performed to validate the effectiveness of the developed algorithm.     

Nonlinear sliding-mode torque control with adaptive backsteppingapproach for induction motor drive

In this paper, the nonlinear sliding-mode torque and flux control combined with the adaptive backstepping approach for an induction motor drive is proposed. Based on the state-coordinates transformed model representing the torque and flux magnitude dynamics, the nonlinear sliding-mode control is designed to track a linear reference model. Furthermore, the adaptive backstepping control approach is utilized to obtain the robustness for mismatched parameter uncertainties. With the proposed control of torque and flux amplitude, the controlled induction motor drive possesses the advantages of good transient performance and robustness to parametric uncertainties, and the transient dynamics of the induction motor drive can be regulated through the design of a linear reference model which has the desired dynamic behaviors for the drive system. Finally, some experimental results are demonstrated to validate the proposed controllers     

Voltage control strategy for maximum torque operation of aninduction machine in the field-weakening region

In this paper, a novel field-weakening scheme for the induction machine is presented. The proposed algorithm, based on the voltage control strategy, ensures the maximum torque operation over the entire field-weakening region without using the machine parameters. Also, by introducing the direct field-oriented (DFO) control, which is insensitive to the variation of machine parameters in the field-weakening region, the drive system can obtain robustness to parameter variations. Moreover, the speed sensorless control can be achieved in the very-high-speed range, where the utilization of the speed sensor is limited. Experimental results for the laboratory induction motor drive system confirm the validity of the proposed control algorithm     

An adaptive hysteresis-band current control technique of avoltage-fed PWM inverter for machine drive system

An adaptive hysteresis-band control method where the band is modulated with the system parameters to maintain the modulation frequency to be nearly constant is described. Although the technique is applicable to general AC motor drives and other types of load, an interior permanent magnet (IPM) synchronous machine load is considered. Systematic analytical expressions of the hysteresis band are derived as functions of system parameters. An IPM machine drive system with a voltage-fed current-controlled PWM (pulse width modulation) inverter has been computer simulated to study the performance of the proposed method     

模糊PID在拉拔机控制系统中的应用

针对拉拔机在拉拔的过程中因负载大小不同而引起不稳定和抖动的现象,设计了模糊PID控制器。模糊PID以系统偏差和偏差变化率作为输入,通过修改PID控制器的参数来获得满意的动态和静态控制性能。仿真结果表明,模糊PID在上升时间和稳态时间上分别比传统PID控制器缩短了0.119 s和0.503 s,在快速性和稳定性上明显优于传统PID控制器。采用这种控制器改善了控制系统的动态性能,提高了系统的控制精度。     

高速激光切割机床数控系统探究

随着经济的迅速发展,我国工业技术也有了较大的改善。现如今切割技术也有了很大的创新改进,新兴的激光切割,它目前已成为热切割技术发展的热点之一,激光切割技术相比较传统切割技术多了高精度、高效率、低污染等优点。为了满足激光切割装备的数字化、精密化等要求,实现此种技术的国产化。本文就高速激光切割机床数控系统各方面进行了研究分析,以此来满足我国对激光切割机床数控技术发展的要求。     

高速激光切割机床数控系统探究

随着经济的迅速发展,我国工业技术也有了较大的改善。现如今切割技术也有了很大的创新改进,新兴的激光切割,它目前已成为热切割技术发展的热点之一,激光切割技术相比较传统切割技术多了高精度、高效率、低污染等优点。为了满足激光切割装备的数字化、精密化等要求,实现此种技术的国产化。本文就高速激光切割机床数控系统各方面进行了研究分析,以此来满足我国对激光切割机床数控技术发展的要求。     

Axial vibration suppression of wire-ropes and container in double-rope mining hoists with adaptive robust boundary control

Under the high-speed and heavy-load operating conditions of the mine hoist, due to its own elastic deformation and unknown interference from the outside world, the wire rope will produce large undesired vibrations, which greatly affects the service life of the wire rope and the comfort of the passengers. Aiming at this problem, taking the double-rope winding hoist as the research object, the Hamilton principle is applied to establish the distributed parameter dynamic model of the system. Considering the uncertainty of system modeling, a parameter adaptive law is designed to fit unknown parameters. On this basis, an adaptive robust boundary controller for suppressing longitudinal vibration of steel wire rope is proposed. The stability of the designed controller is proved by Lyapunov theory, and the experimental verification is carried out on the experimental platform of double-rope winding hoist. The results show that the designed boundary controller can effectively suppress the longitudinal vibration of the lifting rope and the container.     

输出不可量测非线性系统的神经模型参考自适应控制

该文针对被控对象输出不可量测的非线性系统,引入一个便于在线辨识的扩展神经网络模型,提出一种基于前馈-反馈结构的神经网络模型参考自适应控制方法。给出了具有全局收敛性的网络训练算法,并分析了控制系统的稳定性。仿真结果表明该控制方法是有效的,而且对网络初始权值的选取及被控对象特性参数的扰动都具有良好的鲁棒性。     

舵机加载系统的自适应滑模控制策略研究

舵机加载系统主要用于模拟导弹在飞行过程中舵面受到的各种气动力矩,但存在力矩效率低,多余力较多,干扰复杂等特点。为使电动加载系统的仿真度和力矩精度进一步提高,采用自适应滑模控制对多余力矩和其他位置干扰进行抑制,同时对滑模控制的切换函数进行改进,以削弱系统存在的抖振。仿真结果显示,加载系统的精度和抗干扰能力有进一步提高。     

Software package for the performance evaluation of satellitecommunication systems with adaptive allocation of on-board commonresources

Advanced communication satellite systems in which on-board resources could be temporarily assigned to earth-stations undergoing severe rain attenuation are described. Based on a mathematical model of the spatial correlation of rain developed from experimental data, a software package is presented which allows the evaluation of the performance of such systems     

Congestion control for fair resource allocation in networks with multicast flows

We consider the problem of congestion control in networks which support both multirate multicast sessions and unicast sessions. We present a decentralized algorithm which enables the different rate-adaptive receivers in different multicast sessions to adjust their rates to satisfy some fairness criterion. A one-bit ECN marking strategy to be used at the nodes is also proposed. The congestion-control mechanism does not require any per-flow state information for unicast flows at the nodes. At junctions nodes of each multicast tree, some state information about the rates along the branches at the node may be required. The congestion-control mechanism takes into account the diverse user requirements when different receivers within a multicast session have different utility functions, but does not require the network to have any knowledge about the receiver utility functions.     

Novel switching techniques for reducing the speed ripple of AC drives with direct torque control

The main theme of this paper is to present novel switching techniques, which insert zero-voltage vectors and/or more nonzero-voltage vectors to the conventional switching table, for AC drives with direct torque control. For the same sampling frequency of a drive controller, the proposed techniques are quite effective in reducing the torque pulsation and the speed ripples of the motors, as demonstrated in several experimental results. Moreover, the experimental confirmations have been made not only on an induction machine but also on a permanent-magnet synchronous machine.     

模糊自适应PID在汽车底盘测功机中的仿真研究

在汽车底盘测功机研究中,由于汽车底盘测功机是一个复杂的时变非线性、大惯性系统。传统的PID控制对于非线性、时变性的系统难以达到控制精度的要求,而模糊自适应PID控制具有在线自动调整的功能,从对传统的PID与模糊自适应PID比较的基础上,分析了参数对系统性能的影响,并利用MATLAB软件中的模糊工具箱对连续系统进行了仿真,离散系统采用编程仿真,比较结果表明,模糊自适应PID控制器具有良好的跟踪性能,超调量小、控制精度高、调节速度快,可以实现对PID参数的最佳调整。     

基于热处理线淬火机控制策略的研究与应用

介绍了中厚板热处理线淬火设备组成、工艺概况和淬火自动控制系统,介绍了淬火模型的组成及控制策略,着重分析了加热温度和控冷速度对钢的淬透性和硬度等组织性能的影响,并在生产过程中不断优化完善淬后组织预测模型,大大增加NM360钢的强度、韧性,降低碳含量和碳当量。淬火后板材平直度及性能指标达到或优于国外同类进口先进设备的工艺水平,提高钢板的焊接性能,在热处理生产线上具有很高的推广价值。     

On the development of adaptive hybrid active noise control system for effective mitigation of nonlinear noise

The presence of nonlinearities as well as acoustic feedback deteriorates the cancellation performance of the conventional filtered-x LMS (FxLMS) algorithm based active noise control (ANC) systems. With an objective to improve the performance, a novel filtered-su LMS (FsuLMS) algorithm based ANC system which employs a convex combination of an adaptive IIR filter with a functional link artificial neural network (FLANN) is proposed in this paper. The corresponding learning algorithm of the ANC system is derived and used in the simulation study for performance evaluation. Simulation study reveals enhanced performance of the proposed system over that of its component filters.