Swing‐up and stabilization control of a cart– pendulum system via energy control and controlled Lagrangian methods

This paper addresses a swing‐up and stabilizing problem for a cart– pendulum system, which consists of a pendulum and a motor‐driven cart. Existing methods are based on the strategy of swing‐up of the pendulum by energy control methods, then switching the controllers to balance the pendulum when it approaches the upright position. The switching angle influences significantly control performance, so the pendulum might fall down if the angle is inadequately chosen. This paper proposes a swing‐up and stabilizing control method which makes it possible to determine an appropriate switching angle more arbitrarily. In addition to the energy control method for swing‐up, a stabilizing method based on controlled Lagrangians is adopted instead of a linear controller. The attractive domain of the closed‐loop system with this method can be known in advance and is wider than with linear controllers. In this way, our proposed control strategy overcomes the difficulty in choosing the switching angle of the controllers. An experimental result illustrates the effectiveness of the proposed method. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 160(4): 24– 31, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20534     

Adaptive control of an underactuated spherical robot with a dynamic stable equilibrium point using hierarchical sliding mode approach

Unlike the traditional underactuated mechanical system, the equilibrium point of the inner swing‐up suspension of a spherical robot possesses stable and dynamic characteristics. The stable dynamic equilibrium position of the underactuated suspension must agree well with the uncertain rolling resistance in practice. To overcome this special underactuated problem with dynamic equilibrium, we present an adaptive control scheme to enhance the ground adaptability using hierarchical sliding mode approach. The control method can drive the spherical robot to a desired position, and at the same time, the suspension subsystem holds on their dynamic equilibrium points rapidly. The proposed control approaches are verified to be effective by numerical simulation for a spherical robot to achieve satisfactory control performances, such as ground adaptability, rapid convergence, and disturbance rejection. Copyright © 2013 John Wiley & Sons, Ltd.     

Active‐terminated transmitter and receiver circuits for high‐speed low‐swing duobinary signaling

In this work, we propose transmitter and receiver circuits for high‐speed, low‐swing duobinary signaling over active‐terminated chip‐to‐chip interconnect. In active‐termination scheme port impedance of transmitter and receiver is matched with characteristic impedance of the interconnect. Elimination of the passive terminators helps in reducing the transmitted signal level without degrading the 0signal detectability of the receiver. High‐speed current‐mode receiver and transmitter circuits are designed, so that the input port impedance of the receiver and the output port impedance of the transmitter are matched with characteristic impedance of the link. These Tx–Rx pair is used to validate the proposed active‐termination scheme. We also propose a duobinary precoder architecture suitable for high‐speed operation and a low‐power broadband equalizer topology for compensating the lossy long interconnect. The duobinary transmitter and receiver circuits are implemented in 1.8 V, 0.18 µm Digital CMOS technology. The designed high‐speed duobinary Tx/Rx circuits work up to 8 Gb/s speed while transmitting the data over 29.5 in. FR4 PCB trace for a targeted bit error rate (BER) of 10^?15. The power consumed in the transmitter and receiver circuits is 42.9 mW at 8 Gb/s. Copyright © 2010 John Wiley & Sons, Ltd.     

An analytical model of triple‐material double‐gate metal–oxide–semiconductor field‐effect transistor to suppress short‐channel effects

This paper presents an analytical subthreshold model for surface potential and threshold voltage of a triple‐material double‐gate (DG) metal–oxide–semiconductor field‐effect transistor. The model is developed by using a rectangular Gaussian box in the channel depletion region with the required boundary conditions at the source and drain end. The model is used to study the effect of triple‐material gate structure on the electrical performance of the device in terms of changes in potential and electric field. The device immunity against short‐channel effects is evaluated by comparing the relative performance parameters such as drain‐induced barrier lowering, threshold voltage roll‐off, and subthreshold swing with its counterparts in the single‐material DG and double‐material DG metal–oxide–semiconductor field‐effect transistors. The developed surface potential model not only provides device physics insight but is also computationally efficient because of its simple compact form that can be utilized to study and characterize the gate‐engineered devices. Furthermore, the effects of quantum confinement are analyzed with the development of a quantum‐mechanical correction term for threshold voltage. The results obtained from the model are in close agreement with the data extracted from numerical Technology Computer Aided Design device simulation. Copyright © 2015 John Wiley & Sons, Ltd.     

Adaptive concentric power swing blocker

The main purpose of power swing blocking is to distinguish faults from power swings. However, the faults occur during a power swing should be detected and cleared promptly. This paper proposes an adaptive concentric power swing blocker (PSB) to overcome incapability of traditional concentric PSB in detecting symmetrical fault during power swing. Based on proposed method, two pairs of concentric characteristics are anticipated which the first one is placed in a stationary position (outer of zone3) but the position of the second pair is adjustable. In order to find the position of the second pair of characteristic, Static Phasor Estimation Error (SPEE) of current signal is utilized in this paper. The proposed method detects the abrupt change in SPEE and puts the second pair of characteristic in location of impedance trajectory correspondingly. Second concentric characteristic records travelling time of impedance trajectory between outer and inner zones and compares to threshold value to detect symmetrical fault during power swing. If recorded time is lower than threshold, three-phase fault is detected during power swing. Intensive studies have been performed and the merit of the method is demonstrated by some test signals simulations.     

Improved differential evolutionary algorithm for nonlinear identification of a novel vibration‐assisted swing cutting system

Vibration‐assisted swing cutting (VASC) is a new precision machining technology. VASC not only inherits the characteristics of EVC intermittent cutting but also alleviates the problem of EVC residual height. However, system identification is key if you want to achieve precise control. In order to solve this problem, a new improved differential evolutionary (IDE) algorithm is proposed to identify and optimize the Hammerstein‐Wiener model parameter in VASC system. IDE algorithm is applied to transform the identification problem of the model into the optimization problem in the parameter space, and the optimal solution of the parameter of the model in the parameter space is obtained. Meanwhile, the IDE algorithm and the conventional five differential evolutionary algorithms perform performance comparison tests on six different test functions. The test results show that the IDE algorithm is strengthening the global search capability, accelerate the convergence rate to the global optimal solution, and indicate that the IDE algorithm can be effectively applied to the parameter optimization of Hammerstein‐winner model. Based on the input and output data collected from the experiment, the accuracy of the identification model can be up to 98%, which prove the superiority of the proposed IDE algorithm for system identification.     

Position and altitude tracking control for toe support phase of biped walking robot

No paper has been published on the active use of the foot toe of biped walking robots. In other words, the sole of the supporting leg is usually assumed to completely contact the ground. To maintain this condition, the robot walking has a restriction such as the maximum walking speed limitation. If the point contact of the toe to the ground through walking is available, a variety of walking can be realized. In this paper, a new control method for biped robots, in which the contact of the sole to the ground becomes a point contact, is proposed. The COM (Center of Mass) and swing leg can track the desired path and each heel joint angle can be controlled by the proposed controller while a biped walking robot is following a forward falling. Therefore, the motion of the body does not need to be limited to quiet motion. The proposed method is verified by simulation and experimental results with “Ken,” a six‐joint DOF biped robot. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 157(1): 72–79, 2006; Published online in Wiley InterScience ( http://www.interscience.wiley.com ). DOI 10.1002/eej.20094     

Integrated reproduction of human motion components by motion copying system

Currently, the development of leading‐edge technology for recording and loading human motion on the basis of haptic information is required in the fields of manufacturing and human support. Human movement is an assembly of motion components. Since human movements should be supported by a robot in real time, it is necessary to integrate the motion components that were saved earlier. Once such motion integration is realized, future technology for use in daily human life can be developed. This paper proposes the integrated reproduction of the decomposed components of human motion by using a motion copying system. This system is the key technology for the realization of the acquisition, saving, and reproduction of real‐world haptic information. By using the proposed method, it is possible not only to achieve expert skill acquisition, skill transfer to robots, and power assist for each motion component, but also to open up new areas of applications. © 2012 Wiley Periodicals, Inc. Electr Eng Jpn, 181(1): 28–35, 2012; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.21263     

A novel out of step relaying algorithm based on wavelet transform and a deep learning machine model

Out-of-step protection of one or a group of synchronous generators is unreliable in a power system which has significant renewable power penetration. In this work, an innovative out-of-step protection algorithm using wavelet transform and deep learning is presented to protect synchronous generators and transmission lines. The specific patterns are generated from both stable and unstable power swing, and three-phase fault using the wavelet transform technique. Data containing 27,008 continuous samples of 48 different features is used to train a two-layer feed-forward network. The proposed algorithm gives an automatic, setting free and highly accurate classification for the three-phase fault, stable power swing, and unstable power swing through pattern recognition within a half cycle. The proposed algorithm uses the Kundur 2-area system and a 29-bus electric network for testing under different swing center locations and levels of renewable power penetration. Hardware-in-the-loop (HIL) tests show the hardware compatibility of the developed out-of-step algorithm. The proposed algorithm is also compared with recently reported algorithms. The comparison and test results on different large-scale systems show that the proposed algorithm is simple, fast, accurate, and HIL tested, and not affected by changes in power system parameters.     

A novel power swing blocking scheme using adaptive neuro-fuzzy inference system

A power swing may be caused by any sudden change in the configuration or the loading of an electrical network. During a power swing, the impedance locus moves along an impedance circle with possible encroachment into the distance relay zone, which may cause an unnecessary tripping. In order to prevent the distance relay from tripping under such condition, a novel power swing blocking (PSB) scheme is proposed in this paper. The proposed scheme uses an adaptive neuro-fuzzy inference systems (ANFIS) for preventing distance relay from tripping during power swings. The input signals to ANFIS, include the change of positive sequence impedance, positive and negative sequence currents, and power swing center voltage. Extensive tests show that the proposed PSB has two distinct features that are advantageous over existing schemes. The first is that the proposed scheme is able to detect various kinds of power swings thus block distance relays during power swings, even if the power swings are fast or the power swings occur during single pole open conditions. The second distinct feature is that the proposed scheme is able to clear the blocking if faults occur within the relay trip zone during power swings, even if the faults are high resistance faults, or the faults occur at the power swing center, or the faults occur when the power angle is close to 180°.     

Adaptive formation control of autonomous underwater vehicles with model uncertainties

This paper investigates the formation control problem of underactuated autonomous underwater vehicles (AUVs). What makes this problem different and challenging is that, in the AUV model, the mass and damping matrices are not diagonal with nonzero off‐diagonal terms and unknown hydrodynamic damping terms. To address the effect of nonzero off‐diagonal terms, we introduce a coordinate transformation, while the unknown hydrodynamic damping terms are approximated adaptively by a neural network. Then, a leader‐follower control strategy is presented, where each follower needs to track a virtual vehicle. This strategy translates the formation control problem into a set of position (including heading) tracking problems for the following AUVs. The position and heading tracking controller is designed based on Lyapunov direct method and backstepping technique, taking into account the effect of the nonzero off‐diagonal terms in the mass matrix and the unknown hydrodynamic damping terms. Simulations are given to demonstrate the effectiveness of the control method proposed.     

一种区分振荡与故障的新方法

提出了一种能区分振荡、故障、振荡中故障的新方法，其基于电流故障分量的变化方式 而判别。为了校验启动元件在振荡中以及在振荡中发生故障情况下的动作情况，应用一种新 的振荡模型和振荡中故障的模型。这种新的启动元件能明确地区分系统振荡以及故障（包括 振荡中故障）。     

大型立式机组轴线最大摆度及方位分析

指出传统方法确定的轴线摆度最大值及其方位存在的较大误差，推导出根据传统方法测量值精确计算摆度最大值及其方位公式，分析传统方法的误差及其对安装的影响并举实例，此方法对机组安装轴线摆度质量控制，提高摆度有较大意义。     

A novel PWM technique with switching‐loss reduction for independent drive of two 3‐phase AC motors fed by a five‐leg inverter

This paper presents a novel pulse width modulation (PWM) technique with switching‐loss reduction for a five‐leg inverter (FLI). The PWM technique, in which the available maximum voltage for two motors adds up to DC bus voltage, has been proposed as the strategy for the FLI. Therefore, the DC bus voltage is fully available as the PWM strategy. However, the conventional PWM technique requires the frequency, phase, and amplitude of the phase voltage commands of a motor to produce zero‐sequence voltages (ZSVs). The novel PWM strategy has some efficient features. These features are discussed in this paper. The validity of the novel PWM technique will be shown by experimental results. © 2011 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

CARR堆自然循环瓣阀设计及验证

CARR堆自然循环瓣阀是一种新型的旋启式止回阀。介绍了CARR堆自然循环瓣阀的功能要求、工作原理、结构设计和计算、材料选择等设计工作内容。瓣阀的性能试验结果表明,该设计满足要求。     

Formation control of multiple nonholonomic mobile robots

Tracking control problem of multiple mobile robots is considered. Our system is composed of a reference and follower robots of unicycle type. The robots are assumed to satisfy pure rolling and nonslipping conditions, which lead to nonholonomic constraints. The purpose is to control the followers so that the reference is tracked with arbitrary desired clearance and also to avoid interrobot collisions. To accomplish this goal, we first introduced a virtual robot (VR) tracking control to establish and maintain the formation when no collision is detected. VR is an ideal robot fixed with each follower and helps in simplifying the control, as the tracking error becomes zero in the final stage. During the process, if the possibility of collision is detected, a collision avoidance technique (l?ψ or l?l control) will be applied to the lower priority robot. The result of this control gives a monotonic convergence in an internal shape of distance variables, which enables us to predict the movement of the robots during this control and leads to collision‐free movement. These processes are repeated until the desired motion is accomplished. Simulation results prove the efficiency of our control techniques. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 157(3): 81–88, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20192 Copyright © 2006 Wiley Periodicals, Inc.     

Adaptive interconnection and damping assignment passivity-based control for an underactuated cable-driven robot

Interconnection and damping assignment passivity-based control (IDA-PBC) provides a general framework to stabilize underactuated mechanical systems by assigning the desired Hamiltonian to the system, which is obtained from the solution of partial differential equations. In this article, the IDA-PBC method is applied to an underactuated cable-driven robot to stabilize out-of-plane motion of the system. An adaptation law for the system's mass is designed such that asymptotic stability is ensured with positive tension in cables through the direct Lyapunov method. The results are verified through some simulations.     

Toward Okinawa‐Style Robot‐Embedded Systems

For the Okinawan economy to grow independently, it is essential to create new businesses; this will require the cultivation of technologies that will form the basis for those businesses, as well as the training of technicians and researchers. To promote the creation of new businesses and innovation that are “Unique to Okinawa,” the Institute of Electrical Engineers of Japan set up a cooperative research committee to develop Okinawa‐style robot‐embedded systems. We proposed the concept of Okinawa‐style robot‐embedded systems. To realize this concept, we organized technical meetings to promote research. Now our research focuses on developing playback‐type navigation robots for use in land and air, and also on developing an underwater robot for conserving marine life in the waters around Okinawa. It is necessary to conduct proper measurements, observations, and sampling in water. To successfully perform these tasks, we needed to develop an underwater robot. We have made efforts in developing hardware, software, and applications for embedded techniques. We suggest that coarsely integrated operand scanning (CIOS) and bilateral filters (BFs) be implemented in hardware. We also developed devices to improve quality of life and to support disabled children through software.     

Assisted Control of Step Passage Motion and Its Comfort Evaluation in Two‐Wheel Wheelchair Systems

Two‐wheel wheelchair systems have been attracting attention because their mobility is better than that of conventional four‐wheel wheelchair systems. However, two‐wheel wheelchair systems must achieve stabilization control in the presence of disturbances caused by modeling error or the road situation, since these systems are underactuated systems similar to the inverted pendulum. In this investigation, step passage motion in two‐wheel wheelchair systems is considered. A reaction torque observer was employed to estimate the pitch angular interaction torque and the pure external wheel disturbance. Repulsive compliance control was employed to determine the optimal pitch angle command to compensate for the center of gravity of the user and to assist the whole step passage motion. Experimental results are evaluated in terms of user comfort by utilizing the ISO 2631‐1 generalized index.     

Performance Evaluation of an Image‐Space Observer‐Based Visual Servoing System

In recent years, robots have come to be required to operate in various environments and situations. Therefore, robots have to recognize the environment they are in and adapt to any situations that present themselves. The purpose of this research is to increase the tracking speed and robustness of a visual servoing system. A 3‐link planar manipulator provided with a CCD camera is used to track the target. In order to track the target, an image‐based tracking method, suitable for high‐speed tracking, is used. This paper proposes an image‐space observer (IOB), which compensates disturbances in the image space. A zero‐order hold is introduced to the IOB to enhance the performance of the visual servoing system. The validity of the proposed method is confirmed through experiments.