Adaptive boundary control for flexible three‐dimensional Euler‐Bernoulli beam with input signal quantization

This paper proposes an adaptive boundary control scheme for the flexible three‐dimensional Euler‐Bernoulli beam with input signal quantization. Considering the coupling effect between the axial deformation and the transverse displacement, the dynamics of the flexible system are represented by partial differential equations and ordinary differential equations. Input signals in modern control systems are often quantized before being transmitted through communication channels in technology engineering. Logarithmic quantitative controllers are designed to suppress the vibration of the beam. It is proved that the proposed control scheme can be guaranteed in handling the vibration of the beam and input signal quantization simultaneously. Finally, numerical simulations illustrate the effectiveness of the results.     

Smooth switching control for transfer from the Automatic Traveling Mode to the Power Assist Mode of the Skill‐Assist

The objective of this study is to verify a smooth switching control method for transfer from the automatic traveling mode (ATM) to the power assist mode (PAM) of Skill‐Assist. A control law including time‐varying impedance parameters is utilized to attain the objective. The experimental result shows that the transfer from ATM to PAM was successfully performed by the smooth switching control method. © 2007 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Vibration control of flexible arm by multiple observer structure

This paper describes vibration control of a flexible arm by multiple‐observer structure using the accelerations of the arm. In general, a flexible arm has several oscillation modes. In the model of a flexible arm described as a two‐mass resonant system, the reaction torque feedback makes the flexible arm system stable. In the N‐mass resonant system, it is known that the reaction torque feedback makes all oscillation modes, only the reaction torque feedback is not enough to make the system stable. Resonance ratio control with the arm disturbance observer has been proposed. The arm disturbance observer is able to suppress the disturbance applied to the tip, but it is not sufficient for the disturbance applied to other points on the arm. The aim is to make the control system robust to arm inertia variation and disturbance. This paper proposes vibration control of flexible arm by acceleration feedback, and disturbance rejection by multiple‐observer structure using the acceleration of the arm. The validity of the proposed method is shown by simulations and experiments. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 154(2): 68–75, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20175     

永磁直线电机驱动单连杆柔性臂系统的试验模型辨识

针对永磁直线电机（PMLM）驱动单连杆柔性机械臂（SLFM）做点到点运动时存在残余振动从而影响柔性臂末端迅速精准定位的问题,研究了基于PMLM平动柔性臂系统的试验模型辨识问题。建立了从位置指令到柔性臂根部应变振动信号的传递函数模型,并对模型采用阶跃输入法和扫频激励法进行了试验辨识,为开展基于PMLM的平动柔性臂系统抑制残余振动控制提供了模型基础。试验结果得出辨识模型在2种激励信号下的仿真输出与实际结构动态响应的吻合度均较高,验证了模型辨识结果的正确性,并反映了基于PMLM的平动柔性臂系统的动力学特性。     

基于电感电压反馈和输入整形技术的LC滤波器混合阻尼控制

电流型PWM整流器采用LC环节来滤除谐波及帮助器件换流,LC型滤波器呈二阶特性,存在谐振尖峰,且电容阻尼较小,在控制系统存在扰动的情况下,容易引起电流波形畸变和振荡。提出了一种采用输入整形技术和电感电压反馈结合的控制策略,输入整形技术能够有效地抑制小阻尼系统的振荡,电感电压反馈控制能够在外部干扰抑制网侧电流波形畸变。结合两者的优点,可有效地解决电流型脉宽调制整流器网侧电流振荡和畸变。仿真验证了所提出的控制策略能够有效减少电流畸变,增加系统的稳定性,并具有一定工程实用性。     

Adaptive constraint control for flexible manipulator systems modeled by partial differential equations with dead-zone input

In this article, based on partial differential equations (PDEs), the flexible manipulator system with both dead-zone input and state constraints is studied. The dynamic model of the flexible manipulator system is described by PDEs. The parameters of the dead-zone input are unknown, and the state constraint problem is also considered. An adaptive approach is proposed to offset the effects caused by dead-zone input. Thus, to guarantee that all states remain within their respective constraint regions, the boundary control law based on the barrier Lyapunov function is given, and an adaptive controller is designed. According to the Lyapunov analysis method, the control method is given to ensure that all signals of the closed-loop system are bounded and all states satisfy the constraint conditions. Finally, simulation results show the effectiveness of the proposed control method in this article.     

Vibration control for pneumatic isolation table with feedforward control input

In this paper, we consider a vibration suppression problem for a pneumatic isolation table with on–off valves using the feedforward control input profile. In this system, it is possible to enhance the vibration suppression performance by adjusting the flow rate of air into and from air springs. However, there is a significant problem that a steady‐state deviation, namely an offset, for displacement of the table occurs. Therefore, we propose an efficient search method of the optimal feedforward control input profile, which provides high vibration suppression performance without a steady‐state deviation. A key idea is to update the control input profile to belong to a space where velocity of the table does not change.     

Vibration signal analysis for condition monitoring of puffer‐type high‐voltage circuit breakers using wavelet transform

Nowadays, the goals of electrical supply utilities are to reduce equipment failures, extend service life, increase equipment reliability, and reduce their related operating and maintenance costs. The high‐voltage circuit breaker is an important element in the electrical network. In order to determine or to detect abnormal conditions inside a circuit breaker, powerful vibration analytical techniques have been proposed. In this paper, a vibrational analysis is carried out by analyzing the signal in the time–frequency domain under no‐load switching operations with a commercially available high‐voltage puffer‐type circuit breaker without opening its major parts. Vibration of the circuit breaker poles, operating mechanism, and various monitored parameters were recorded under normal and variable operating conditions. Moreover, a synthetic mechanical damage introduced deliberately is also investigated. The experimental result indicates that mechanical defects can be detected by analyzing the vibration signal. © 2011 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Adaptive output feedback dynamic surface control of stochastic nonlinear systems with state and input unmodeled dynamics

In this paper, an adaptive neural output feedback control scheme is investigated for a class of stochastic nonlinear systems with unmeasured states and four kinds of uncertainties including uncertain nonlinear function, dynamic disturbance, input unmodeled dynamics, and stochastic inverse dynamics. The unmeasured states are estimated by K‐filters, and stochastic inverse dynamics is dealt with by constructing a changing supply function. The considered input unmodeled dynamic subsystem possesses nonlinear feature, and a dynamic normalization signal is introduced to counteract the unstable effect produced by the input unmodeled dynamics. Combining dynamic surface control technique with stochastic input‐to‐state stability, small‐gain condition, and Chebyshev's inequality, the designed robust adaptive controller can guarantee that all the signals in the closed‐loop system are bounded in probability, and the error signals are semi‐globally uniformly ultimately bounded in mean square or the sense of four‐moment. Simulation results are provided to verify the effectiveness of the proposed approach. Copyright © 2015 John Wiley & Sons, Ltd.     

Accurate contour control of mechatronic servo systems without parameter adjustment by use of modified input data method

This paper describes a technique of accurate contour control by a modified input data method for industrial mechatronic servo systems with unadjusted servo parameters. Adjustment of the servo parameters in order to achieve high‐performance contour control in mechatronic servo systems is a tedious task. The modified input data method can realize satisfactory contour control performance accuracy within rather large tolerances for servo parameter errors. The effectiveness of the proposed method has been verified by simulation and experimental studies of contour control of an actual mechatronic servo system. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 160(4): 60–69, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20322     

Levitation force assist through LSM armature currents in superconducting maglev vehicle

In a superconducting maglev vehicle, levitation forces produced by the interaction between the ground levitation coils and the onboard SCMs become insufficient when the running speed is low. This paper presents a levitation force assist method through the control of LSM armature currents, which usually function to generate propulsion forces. The levitation assist system is constructed in terms of d‐axis armature currents, leading to the definition of the vertical force coefficient of propulsion system. The calculated results show the feasibility of the system, which produces damping forces as well as levitation assist forces. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 155(4): 45–52, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20260     

基于卡尔曼滤波的风机控制系统优化

为进一步优化风机控制效果,缓解输入信号滞后于风能变化问题;在原有的控制算法基础上,引入卡尔曼滤波预测控制算法。建立了传动系统柔性模型,推导了卡尔曼滤波系统更新方程,并根据卡尔曼滤波原理研究了相关协方差确定方法,得到了滤波系数回归更新方法。利用系统平台和bladed软件进行仿真,证明了算法对传动振动优化效果和对功率曲线平稳性优化效果。结果表明,算法具有减缓传动链振动和平滑功率曲线的作用,可以在风场推广应用。     

Indirect adaptive fuzzy control for input and output constrained nonlinear systems using a barrier Lyapunov function

In this paper, a novel indirect adaptive fuzzy controller is proposed for a class of uncertain nonlinear systems with input and output constrains. To address output and input constraints, a barrier Lyapunov function and an auxiliary design system are employed, respectively. The proposed approach is explored by employing fuzzy logic systems to tackle unknown nonlinear functions and combining the adaptive backstepping technique with adaptive fuzzy control design. Especially, the number of the online learning parameters are reduced to 2n in the closed‐loop system. It is proved that the proposed control approach can guarantee that all the signals in the closed‐loop system are bounded, and the input and output constraints are circumvented simultaneously. A numerical example with comparisons is provided to illustrate the effectiveness of the proposed approach. Copyright © 2013 John Wiley & Sons, Ltd.     

柔性机械臂振动控制中的压电传感器故障诊断

压电传感器常被应用于结构的振动控制中,为了解决压电传感器故障给控制系统的带来的不稳定问题,根据压电柔性臂振动用压电传感片故障的特点,提出运用小波包变换和RBF神经网络的故障诊断方法。首先运用小波包分解和重构原理将传感器输出信号分解到不同频段中,提取每个频段的能量作为状态监测的特征向量,作为RBF网络的输入,然后利用最佳的RBF神经网络进行压电传感器故障分类。实验结果表明该方法具有良好的非以此线性跟踪能力,置信度达到90%,为后续振动容错控制研究奠定良好的基础。     

A damping of rotor natural vibration in three‐phase hybrid stepping motors

This paper proposes a damping method of rotor natural vibration in three‐phase hybrid stepping motors, in which optimal commutation signals are calculated from the period of the natural vibration measured by detecting the motor voltages. Moreover, an acceleration and deceleration pattern is derived from a simple model of the rotor vibration, to suppress undesirable transient oscillation in acceleration, deceleration, and positioning operations. An experimental drive system has been implemented and tested to confirm the effectiveness and versatility of the proposed method. Some experimental results show that the experimental system can damp the rotor natural vibration even if the rotor inertia varies. Compared with the conventional pattern, it is confirmed that the proposed pattern makes a great contribution to damping the undesirable transient oscillations. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 144(3): 69–77, 2003; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10153     

Manoeuvring and vibration reduction of a flexible spacecraft integrating optimal sliding mode controller and distributed piezoelectric sensors/actuators

This investigation is to apply optimal sliding mode (OSM) control theory and distributed piezoelectric sensor/actuator technology to vibration control of a flexible spacecraft. An approximate analytical dynamic model of a slewing flexible spacecraft with surface‐bonded piezoelectric sensors/actuators is developed using Hamilton's principle with discretization by assumed model method. To satisfy pointing requirements and simultaneously suppress vibration, two separate control loops are adopted. The first uses the piezoceramics as sensors and actuators to actively suppress certain flexible modes by designing a positive position feedback (PPF) compensators that add damping to the flexible structures in certain critical modes in the inner feedback loop; then a second feedback loop is designed using OSM control to slew the spacecraft. The OSM controller minimizes the expected value of a quadratic objective function consisting of only the states with the constraints that the error states always remain on the intersection of sliding surfaces. The advantage in this method is that the vibration reduction and attitude control are achieved separately in the two separate feedback loops, allowing the pointing requirements and simultaneous vibrations suppression to be satisfied independently of one another. An additional attraction of the design method is that the selection of PPF gain is determined by introducing a cost function to be minimized by the feedback gains which are subject to the stability criterion at the same time, such that the feedback gains are selected in a more systematical way to avoid the arbitrary selecting of feedback gains. The proposed control strategy has been implemented on a flexible spacecraft, which is a hub with a cantilever flexible beam appendage and can undergo a single axis rotation. Both analytical and numerical results are presented to show the theoretical and practical merits of this approach. Copyright © 2006 John Wiley & Sons, Ltd.     

In‐Air finger motion interface for mobile devices with vibration feedback

In this paper, we propose the ‘in‐air finger motion interface’, which solves a problem users face in interacting with mobile devices. The interface uses only a single small camera to track the three‐dimensional (3D) position of the user's finger. The finger region is robustly extracted by using flashing infrared light‐emitting diodes (LEDs) and by obtaining the difference image between an illuminated image and a nonilluminated image. The movement of the finger is modeled by transformation of a finger image, and its parameters are accurately estimated by iterative template matching. As a result of the evaluation, an operating area 131% larger than the size of the display and accuracy of input action of 0.6 mm in the x‐direction are realized. Finally, to investigate the effect of vibration feedback, we conducted a study and found that vibration feedback significantly reduces the average time to finish the task as well as the number of input errors. © 2014 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Input power factor control of three‐phase to three‐phase matrix converters

This paper presents input power factor control of three‐phase to three‐phase matrix converters. The authors propose three kinds of switching patterns for the matrix converters that can realize an arbitrary input‐power‐factor angle between 0 and 2π and reduce the number of commutations in all three phases to four during the control period. Also, the control range of the output voltage reference in the proposed control scheme is derived. The improvement of the input power factor by using the proposed control algorithm has been verified by experiments. © 2011 Wiley Periodicals, Inc. Electr Eng Jpn, 178(3): 42–52, 2012; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21199     

最优模糊控制在悬臂梁振动控制系统中的研究

基于模糊控制的振动控制方法,针对振动系统,分析了一种振动控制方法,通过传感器将信号采集进来,由最优控制理论离线计算得到理论输出值,并将理论输出值与对应的系统输入值对应起来,从而建立拥有最优解的模糊控制规则表,并在线处理振动输入信号和输出最优的控制信号作用于执行器,产生相应的执行力来抑制悬臂梁的振动,从而达到振动控制的目...     

Fully parameterized fixed‐order controller design for H∞ loop shaping method using frequency responses—extension to MIMO systems

Robust control is often applied to systems with uncertainties and disturbances. Above all, the H∞ loop shaping method is known to achieve good control performance and robustness. In this method, the final controller consists of weighting functions and a stabilizing controller. The stabilizing controller is derived for the shaped plant to suppress the H∞ norm of the transfer matrix consisting of a sensitivity function, a complementary sensitivity function, and so on. In addition, the stabilizing controller improves robust stability margin while keeping gain characteristic of the shaped plant if weighting functions are suitable. As a result, the closed‐loop system is well‐balanced between good tracking and robustness. However, a final controller tends to be high‐order. For this problem, reduction techniques are often applied to the final controller. In this case, performance and stability is not always adequately evaluated due to errors by the controller reduction. This paper proposes a fully parameterized fixed‐order controller design method using frequency responses of the plant. We formulate a design problem for multi‐input–multi‐output systems as an optimization problem. Therefore, we can directly design a low‐order controller from frequency responses using the iterative LMI optimization. Accordingly, we can avoid to deteriorate the evaluation of performance and stability.