Discrete fuzzy variable structure control for pantograph position control

A discrete fuzzy variable structure control is developed for high-speed rail pantograph position control systems in the presence of system uncertainty and external perturbation. The proposed method gives a simple and effective tuning algorithm for the control law. The switching surface is defined using the system output signals. The stability of this control system is guaranteed and robust output performance is ensured. The closed-loop eigenvalues are placed stable. The control system is guaranteed driven to the quasi-sliding mode. Fuzzy logic serves to detect and accommodate the unexpected perturbation.     

Barcode-based position control servo for high-speed conditions

A barcode-based position controlling method for high-speed conditions was introduced to deal with the position control in some conditions where it cannot be done quickly and precisely using traditional methods. The position feedback will depend on the decoding of a specifically redesigned barcode with a special structure. By using the angle encoder and interpolation arithmetic, high precision position deviations can be attained. Then position correction will be done through the control algorithm and servo system. The design and decoding of the barcode and the method of obtaining extremely precise deviation are illuminated. In theory, this method of control servoing is very suitable for its real-time, high-precision and high-speed applicability. Translated from Journal of Shanghai Jiaotong University, 2006, 40(3): 456–465 [译自: 上海交通大学学报]     

自动离合器位置跟踪神经元自适应PID控制

针对自动离合器位置难以准确快速跟踪控制的问题,在采用蜗卷弹簧作为补偿装置改善驱动机构性能基础上,设计了一种具有前馈作用的增益可调神经元自适应PID控制器,利用前馈控制加快控制器的响应速度,利用神经元的自学习功能实现权值的自动调整,采用PSD算法实现增益的自动调整.实验结果表明,与常规控制器相比,该控制器用于离合器位置跟踪控制动、静态误差小,能够适应离合器负荷和目标接合速度的非线性变化,具有较好的鲁棒性,能够满足离合器位置跟踪控制要求.     

Decentralized control based on equilibrium point control for a three-machine electric power model system

Electric power systems have become larger and more complex year by year, and the number of decentralized power sources is rapidly increasing, Tberefore, to guarantee high reliability and security, decentralized control based on the decentralization of power systems needs to be developed. In this paper, a decentralized system is constructed by viewing the whole system from the perspective of the generator-bus with the largest power. Since the decentralized system is identified as a one-machine infinite-bus power model system with AVR and GOV, the equilibrium point control, proposed by the authors for a one-machine system, can be applied to it. Control inputs u_a · u_g for AVR · GOV are determined, and the equilibrium points of the decentralized system can be moved by changing the feedback gains. In particular, the unstable equilibrium point is set near the outside of the limiters for AVR · GOV, and stability in the limiters is guaranteed. Thus, it is shown that, by repeating the same steps for other generators, decentralized control for the three-machine model system can be attained. © 1998 Scripta Technica. Electr Eng Jpn, 122(3): 28–36, 1998     

Centralized optimal position control for active magnetic bearings: comparison with decentralized control

This paper discusses a closed-loop centralized control for a multi-input multi-output active magnetic bearing system. A genetic algorithm for design and a credible comparison of different controller structures are proposed. The evaluation of the design trade-offs of linear-quadratic and loop transfer recovery controllers are studied. The model-based controllers are compared with the classical PID controller and the cascaded PI/PD controller. The properties of the tested control configurations are examined using maximum singular values of the output sensitivity function of the closed-loop system and the tolerated disturbance at the input of the plant. Furthermore, indices such as measured peak output sensitivity, singular values of the uncertain control system, responses to the step reference position, step disturbance, and impulse force disturbance are examined. A good agreement between the simulation and the experimental results from the test-rig is shown.     

玻璃基板码垛机械手位置的迭代学习跟踪控制

码垛机械手在玻璃基板生产过程中发挥着至关重要的作用。针对玻璃基板码垛机械手码垛过程具有较强重复性的特点,提出迭代学习的码垛机械手位置跟踪控制方法。考虑到运行过程中出现的非重复性干扰设计了鲁棒迭代学习控制器。同时采用Lyapunov函数分析了码垛机械手的收敛性。理论结果表明,鲁棒迭代学习控制算法可以保证码垛机械手的位置跟踪误差收敛到0。仿真结果表明,所提出的鲁棒迭代学习控制算法,较好地抑制了非重复扰动的影响,有效提高码垛机械手的位置跟踪性能,经过20次的迭代,控制精度能达到0．01mm。在实验测试中,相邻两个玻璃基板间的码垛误差最大不超过0．1mm,取得了良好的控制效果。     

空间机械臂关节容错控制系统研究

针对空间机械臂高可靠性要求,提出一种基于双绕组永磁同步电机的关节容错控制系统.与传统控制系统相比,该控制系统使得机械臂关节保持了较小的体积和重量,能够容忍主份和备份子系统之间发生多个不重叠故障,且能在单个子系统发生故障而断电的情况下,维持关节的不间断工作,从而解决了传统双绕组电机控制系统不能容忍电源及控制器出现故障的问...     

Decentralized PI/PD position control for active magnetic bearings

This paper discusses a closed-loop decentralized control for active magnetic bearings. A cascade connection of PI and PD position controllers is proposed. The control design is based on a simplified linearized model for one axis using a root locus. An excellent agreement is noticeable between simulation and experimental results. It has been shown, that the presented PI/PD control guarantees satisfactory high damping and stiffness of the overall system.     

仿人灵巧手关节的位置/力矩控制

为了使仿人灵巧手完成各种精细作业,提出了一种新的关节位置／力矩控制方法。在自由空间和约束空间中分别采用滑模位置控制和具有前馈的PD力矩控制,在过渡过程中使用系统观测器切换控制模式。这种方法可以使关节在自由空间和约束空间中分别实现良好的轨迹跟踪和力矩跟踪,在过渡过程中实现控制模式的可靠切换和系统的稳定过渡。实验证明了该方法的有效性。     

桥式起重机位置跟踪及防摆的迭代学习控制

桥式起重机运行时,小车移动引起的货物摆动影响了运输效率,容易引发事故,桥式起重机的定位及防摆问题引起了众多专家的关注。针对桥式起重机重复运动的情况,采用迭代学习控制策略来实现位置跟踪及角度控制。根据拉格朗日方程建立了桥式起重机的三维数学模型。设计了桥式起重机角度控制的迭代学习控制算法,并证明了算法的收敛性。研究表明,迭代学习控制可有效利用桥式起重机运行的重复信息,经过一定次数的迭代学习后,位置跟踪误差为0,摆角抑制在7°以内。仿真示例验证了方法的有效性。     

位置伺服系统滑模补偿器设计

在位置伺服控制系统中,古典频域校正方法虽可有效地针对系统频响要求进行控制器设计,但各种干扰力矩的存在,严重影响了系统的性能.依据原有的频域校正控制器导出滑模切换面,给出了满足系统频响要求的滑模补偿器设计方法,在有效地克服干扰力矩影响的同时,又保证了系统动态频响性能,并已成功应用于某型飞行仿真转台的控制系统中.     

永磁同步电机位置伺服系统的有限时间控制

针对永磁同步电机位置伺服系统控制问题,对有限时间控制技术的应用进行了研究.依据有限时间控制理论,利用反步构造法,对系统的位置环提出了一种基于反馈线性化和有限时间控制技术的策略.对干扰情况下闭环系统的性能进行了严格的数学分析.仿真结果表明:与传统的基于PD和反馈线性化的控制方案相比,基于有限时间控制技术的控制方案不仅使得闭环系统的位置跟踪误差具有更快的收敛速度,而且通过调节控制器参数可以使稳态误差的边界更小,系统具有更强的抗干扰能力.仿真结果验证了该方法的有效性.     

Restoration of use of paralyzed limb muscles using sensory nerve signals for state control of FES-assisted walking.

A real-time functional electrical stimulation (FES) state controller was designed that utilized sensory nerve cuff signals from the cat forelimb to control the timing of stimulation of the Palmaris Longus (PalL) muscle during walking on the treadmill. Sensory nerve signals from the median and superficial radial nerves provided accurate, reliable feedback related to foot contact and lift-off which, when analyzed with single threshold Schmitt triggers, produced valuable state information about the step cycle. The study involved three experiments: prediction of the timing of muscle activity in an open-loop configuration with no stimulation, prediction of the timing of muscle activity in a closed-loop configuration that included stimulation of the muscle over natural PaIL electromyogram (EMG), and temporary paralysis of selected forelimb muscles coupled with the use of the state controller to stimulate the PalL in order to return partial support function to the anesthetized limb. The FES state controller was tested in a variety of walking conditions, including different treadmill speeds and slopes. The results obtained in these experiments demonstrate that nerve cuff signals can provide a useful source of feedback to FES systems for control of limb function.     

Feedback position control apparatus of tokamak plasma horizontal position with a digital drive

A plasma horizontal position feedback control system (PHPFCS) and a digital current drive (DCD) for controlling vertical magnetic field are made on an experimental base, and the horizontal position of a plasma in a small tokamak (HAMANA‐T) is controlled by PID operations from the initial phase of plasma generation. The DCD consists of constant‐current discharge units for multiple condensers and drives a digital current analogous as a whole to the control signal of PHPFCS in the range of ±90 A. The maximum value of the digital current increases in proportion to the number of units. This PHPFCS elongates plasma duration from 1.3 ms to 2.1 ms, smooths the waveform of plasma current, and reduces the plasma loop voltage from 25 V to 20 V. Furthermore, PHPFCS reduces the range of variation in plasma horizontal displacement from 3.5 cm to within 0.5 cm and makes it possible to set accurately the horizontal position from the initial phase in the inner region of a vacuum chamber. © 2000 Scripta Technica, Electr Eng Jpn, 130(4): 26–34, 2000     

Quick and precise position control of ultrasonic motor using hybrid control

The ultrasonic motor has an excellent level of performance and many useful features, including high torque, low speed, compactness in size, and absence of electromagnetic interference. This motor has an especially large holding torque and a high response characteristic, making it ideal for use as a servomotor. The drive principle of the ultrasonic motor is, however, different from that of electromagnetic motors and its mathematical model has not been developed yet. Its speed characteristics, moreover, vary with the driving conditions. Consequently, it is difficult to control the ultrasonic motor while maintaining performance. In this paper, a position control scheme using adaptive control is proposed. The utility and validity of the proposed control scheme is tested in experiment.     

Effect of joint angle on EMG variables in leg and thigh muscles

It is the purpose of this article (a) to show the influence of electrode location on EMG amplitude and spectral variables for simulated and real signals for different muscles of the thigh and leg, (b) to investigate the relative movement of the muscle under the recording electrodes when the joint angle changes for the set of muscles most frequently investigated in gait analysis, and (c) to illustrate how different electrode locations may lead to different interpretations of the muscle activity investigated with amplitude and spectral analysis of the surface EMG signal. The study has been carried out on the following muscles of the leg and thigh: rectus femoris, vastus lateralis, vastus medialis, biceps femoris, semitendinosus, tibialis anterior, gastrocnemius lateralis, and gastrocnemius medialis     

机器人灵巧手柔性关节自适应阻抗控制

针对具有柔性关节的HIT/DLR Ⅱ五指仿人机器人灵巧手,研究了基于关节力矩反馈和非线性补偿的关节空间和笛卡尔空间阻抗控制。通过建立柔性关节机器人灵巧手的控制模型,在HIT/DLR Ⅱ型灵巧手上实现基于无源性控制的柔性关节机器人阻抗控制策略。针对非线性摩擦力和重力对灵巧手阻抗控制的影响,基于扩展卡尔曼滤波器提出了自适应摩擦力观测器,实现了具有摩擦力补偿和基于最小二乘法优化重力补偿的机器人灵巧手自适应阻抗控制。实验结果表明,在具有谐波减速器等柔性环节的机器人灵巧手中,所提出的自适应阻抗控制器提高了位置控制的精确度,并获得了稳定的抓取力。     

中压链式梯次储能系统的电池组均衡控制策略

针对中压链式梯次储能系统电池模块串并联数量受限及梯次电池筛选重组成本高等问题,提出了一种电池组接入方式及涉及簇间均衡、箱间均衡、箱内均衡的电池组均衡控制策略,有效降低了退运动力电池梯次储能应用的难度,同时延长了梯次利用储能电池组的使用寿命,具有均衡效果明显、应用范围广的特点。搭建了仿真平台和实验平台,验证了该均衡控制策略的可行性及在中压链式储能系统中应用的可靠性。