Dynamic Characteristics Analysis of Two‐DOF Oscillatory Actuator and Experimental Verification of Prototype

Recently, linear oscillatory actuators have been used in a wide range of applications. In particular, small linear oscillatory actuators are expected to be used in haptic devices by being extended to provide multi‐degree‐of‐freedom motion with arbitrary acceleration. In this paper, we propose a compact two‐DOF oscillatory actuator that can move in various directions on a plane. The static and dynamic characteristics of the actuator are determined by the 3D finite element method. The effectiveness of this method is shown through a comparison of the measured results with the experimental results from a prototype. © 2013 Wiley Periodicals, Inc. Electr Eng Jpn, 186(1): 58–65, 2014; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.22312     

Rotary actuators with multipole ring magnets

Rotary actuators are electromagnetic devices developing mechanical torque with limited rotary motion. Because of their simplicity and low cost they are finding more and more applications, especially in the automotive field. This paper describes a novel homopolar rotary actuator with a ring-type radially magnetized multipolar permanent magnet featuring a high force density “transverse flux” configuration which performs a spring action by developing electromagnetic torques with limited angular movement. Because of the magnetically complicated and nonsymmetrical rotary actuator configuration, the analysis of this actuator is based on 3-D finite element software. The analysis, which is well supported by test results, shows that symmetrical magnetic forces in both directions of rotation were achieved with a stable equilibrium position, satisfying all design requirements to enhance the basic hydraulic power steering system of passenger vehicles     

A 2-dimensional impact driven precise actuator using piezoelectric bimorphs

A new precise actuator is proposed, which is actuated by the impact force of an end-loaded piezoelectric bimorph cantilever, and bears two degrees of freedom for translation and rotation. The dynamic characteristics of the piezoelectric bimorph were analyzed by FEM, and are further proved by experimental tests. A new control system for the actuator was put forward and tested, which is called the fixed-frequency with adjustable voltage. In addition, the actuator’s performance of translation and rotation were both measured. The results demonstrate that the actuator is characterized by a simple structure, large movement range, strong driving ability and high positioning resolution. Its cost is estimated at only 1% of the traditional impact actuators. __________ Translated from Journal of Jilin University (Engineering and Technology Edition), 2006, 36(1): 67–71 (in Chinese)     

XYΘ actuators using piezoelectric and electromagnetic actuators

Microactuators with multiple degrees of freedom, which can provide many benefits in precision engineering, are in demand for industrial applications. We propose two new actuators (Y‐type and Δ‐type) which can move in the x, y, and θ directions. They are combinations of piezoelectric and electromagnetic actuators. The proposed actuators realize high resolution via the piezoelectric actuators. We describe the structure and principle of the proposed actuators, and discuss their feasibility. A resolution of 70 nm in the x direction and of 0.5 μrad in the θ direction was obtained with the Y‐type actuator. A resolution of 90 nm in the x direction and of 0.6 μrad in the θ direction was obtained with the Δ‐type actuator. © 2000 Scripta Technica, Electr Eng Jpn, 131(4): 44–51, 2000     

超磁致伸缩致动器的磁滞非线性动态模型

超磁致伸缩致动器的输入磁场与输出应变存在着磁滞非线性。为了控制及使用致动器，必须建立其准确的数学模型。该文基于Jiles—Atherton磁滞模型、二次畴转模型、非线性压磁方程和致动器结构动力学原理，建立了超磁致伸缩致动器的磁滞非线性动态模型。应用该模型对致动器的输出应变进行计算，计算结果与实验结果符合较好，验证了模型的正确性和实用性。     

A 3‐DOF Inchworm Using Levitation Caused by Vertical Vibration

We propose a 3‐DOF inchworm‐type microactuator that uses levitation generated by vertical vibration. The vertical vibration is created by a piezoelectric actuator. The inchworm typically consists of thrust elements and clamp elements. The proposed inchworm, however, does not use any clamp elements. Four levitation elements are connected with four thrust elements, which are stacked‐type piezoelectric actuators. The levitation element consists of a mass, a piezoelectric actuator, and a plate. The vertical vibration of the piezoelectric actuator lifts the levitation elements, which eliminates any friction. By controlling the order of the deformation of the horizontal piezoelectric actuators and the vibration of the vertical piezoelectric actuators, the inchworm engages in linear and rotational motion. The levitation height and the linear and rotational displacement of the inchworm were measured. Experimental results demonstrated the feasibility of the proposed 3‐DOF inchworm. The mechanism described in this paper is effective for a precision positioning system in a clean room.     

Bilateral Control of a Velocity Control System Using Electric and Hydraulic Actuators

Working in extreme environments (e.g., at disaster sites) is dangerous for humans. Hence, it is important to use teleoperated robots in such extreme environments. Because heavy lifting work is involved, hydraulic actuators with high output are more commonly used than electric actuators. Therefore, it is necessary to operate remotely controlled robots driven by hydraulic actuators. Bilateral control is remote control with a sense of force. Because most bilateral control systems have been studied mainly using electric actuators, bilateral control using hydraulic actuators is still a challenge. In this study, we propose placing a bilateral controller between an electric actuator on the master side and a hydraulic actuator on the slave side using position and velocity. The controller exhibits the dynamics of bilateral control systems using position and velocity. In addition, the control performance of conventional methods and that of the proposed method are compared and experimentally verified.     

Robust adaptive active fault‐tolerant control of UAH with unknown disturbances and actuator faults

This paper proposes a robust active fault‐tolerant control (AFTC) approach for medium‐scale unmanned autonomous helicopter (UAH) with rotor flapping dynamics in the presence of unknown external disturbances and actuator faults. The robust items are adopted to improve the disturbance rejection capability of the UAH system. The adaptive fault observers are developed to estimate the fault parameters and the fault detection (FD) algorithms are presented to detect the actuator faults in different loops. In order to obtain satisfactory trajectory tracking performance, a backstepping‐based robust AFTC scheme is designed for the simplified 6‐degree‐of‐freedom (DOF) UAH nonlinear dynamics model and the global stability of the closed‐loop system is proved by using the Lyapunov method. Several groups of numerical simulation results are carried out to verify the effectiveness of the developed method.     

Model predictive control for tendon‐driven balloon actuator on simulation

Many pneumatic actuators have been developed to be lightweight with high output for decreasing the impact force. However, for pneumatic actuators it is difficult to maintain exact control because these actuators have constraints. In this study, we developed model predictive control (MPC) that can accommodate these constraints when applied to the pneumatic actuator we developed. As described here, we compared and evaluated the control performance using MPC and proportional–integral–derivative (PID) control with an anti‐windup control system. © 2016 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

余热锅炉钢结构高强度螺栓转角法连接质量的检验与应用

针对余热锅炉钢结构高强度螺栓在转角法工艺条件下连接,轴向预紧力难以测量和检验,提出了高强度螺栓连接安装质量监督检验的有效方法。通过比较扭矩法和转角法的不同,分析了扭矩与转角之间的关系范围。利用该范围条件通过扭矩可以有效的检验转角和轴向预紧力的方法。最后,对余热锅炉钢结构试验表明了该检验方法的可操作性和有效性．     

六相双定子螺旋运动永磁执行器数学模型研究

针对新型机器人多自由度运动机构的需求,提出了一种新型六相双定子螺旋运动永磁执行器。执行器特点在于每个定子均为六相双Y移30°绕组,两个定子铁心采用螺旋形齿槽结构,对两个定子绕组通入六相不同相序电流组合便可产生多自由度运动方式。执行器具有控制方式灵活、容错性能强、可靠性稳定等优点。首先对螺旋运动永磁执行器的结构及运行机理进行分析,推导了执行器的磁链方程、电压方程、转矩和推力方程。最后构建了瞬态三维多自由度数值分析模型,得到了磁链、电压、转矩和推力的波形,验证了运行机理的正确性。     

Parameter design of event‐driven logic controller for two‐wheeled vehicle

Programmable Logic Controllers (PLCs) are widely used in industry. In PLC‐based control systems, low‐resolution (especially ON‐/OFF) sensors are inexpensive, and actuators are commonly used because they are compatible with programming languages used in PLCs. PLC switches the actuators ON/OFF as the state of the sensor changes between ON/OFF. In designing PLC‐based systems, the design of the parameters of these sensors and actuators (e.g., position of limit switches and torque of motors) is an important problem because they affect the overall performance of the system. This problem, however, has not yet been fully discussed. In the present paper, a systematic design method for this problem is developed. The main concept is to express the model of the system as a Mixed Logical Dynamical System (MLDS) and to formulate the problem as a mathematical programming problem. The developed idea is applied to the line‐following control of a two‐wheeled vehicle. The usefulness of the proposed method is demonstrated through simulation and experiments. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 162(2): 51–60, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20584     

基于ANSYS的断路器保持弹簧冲击响应分析

作为决定断路器性能的关键部件之一,弹簧操动机构性能的优劣将直接对断路器的技术性能产生非常重大的影响。笔者基于ANSYS商用有限元软件,建立了拉伸弹簧的有限元模型,对高压断路器中螺旋拉伸保持弹簧在冲击载荷下的应力分布进行了计算。通过仿真,求得了断路器保持弹簧在冲击载荷作用下应力分布情况,计算结果与实验结果吻合较好。另外,笔者还对断路器保持弹簧的疲劳强度问题进行了研究,分析结果对于今后断路器弹簧操动机构的设计和维护有一定的参考价值。     

基于模型预测的PMSM直接转矩控制转矩脉动抑制方法

针对传统直接转矩控制方法转矩脉动大的问题,提出了一种基于预测控制减小转矩脉动的方法。首先对定子磁链矢量扇区进行了更加细致的划分,增加了可选有效电压矢量的数量,进而提高直接转矩控制的自由度。在此基础上,分析了零电压矢量对定子磁链幅值与转矩的影响,将零电压矢量加入到控制过程中,最后通过预测控制方法选择最优电压矢量。仿真结果表明,所提方法可有效降低转矩脉动,转矩脉动最大可降低61%,同时所提方法与传统直接转矩控制方法相比,具有更好的动态响应性能。     

Realization of instantaneous torque control of an induction motor considering secondary flux as a parameter

Recently, many researches aiming at the realization of high‐performance and high‐precision control of induction motors have been reported, and instantaneous torque control of an induction motor can be regarded as one of the most important topics in this field. In previous works, the authors developed a new method to realize instantaneous torque control of an induction motor with a voltage‐source inverter, and demonstrated both its numerical simulations and experimental results. Unfortunately, the mathematically complicated derivation of the control method made it difficult to understand intuitively, and hindered us from analyzing the detailed characteristics of motor speed changes. In this paper, the authors propose a new method to realize instantaneous torque control of an induction motor, which differs from the concept of vector control. The proposed method is a two‐degree‐of‐freedom control which considers the instantaneous torque command and secondary flux command as parameters. The analytical solution reported here is a particular solution of the differential state equation of an induction motor, and can be expressed as a simple explicit function of the instantaneous torque command, secondary flux command, and motor speed. The authors show the validity of the proposed method through numerical simulations and experimental results. This paper aims the realization of high‐performance control of an induction motor. The authors propose a new method to realize instantaneous torque control without transient torque with a voltage‐source inverter. © 2001 Scripta Technica, Electr Eng Jpn, 137(1): 48–56, 2001     

Experimental Study of DBD Plasma Actuator with Combination of AC and Nanosecond Pulse Voltage

In the last decade, dielectric barrier discharge (DBD) plasma actuators using a combination voltage of AC and a nanosecond pulse have been studied. The combined‐voltage‐driven plasma actuator increases the body force effect, including wall jet and flow suction, by overlapping the nanosecond pulse voltage, while the DBD plasma actuator driven by nanosecond pulses is a flow control actuator generating compression waves due to pulse heating, which makes it possible to supply an active flow control at a high‐speed flow, reported as up to Mach 0.7. In this study, a DBD plasma actuator driven by a combination voltage of sinusoidal AC and nanosecond pulse was experimentally investigated. The time‐averaged net thrust and cycle‐averaged power consumption of the actuator were characterized by using an electrical weight balance and the charge‐voltage cycle of a DBD plasma actuator, respectively. The plasma actuator thrust driven with the combination voltage showed increased thrust with increasing pulse repetition rate. The energy consumption of the actuator was controlled by varying the AC phase when the nanosecond pulse was applied. Therefore, the thrust and power consumption in the actuator were almost independently controlled by the pulse repetition rate and the pulse imposed phase.     

Analysis of primary-on-slider ultrasonic piezoelectric actuators and experiments on multidegree of motion freedom plane actuator

Recently, various machines and tools have been miniaturized, and with this trend, the size of an actuator becomes a very important factor. An ultrasonic actuator is different from other actuators using electromagnet force in the driving principle. The structures of an ultrasonic piezoelectric actuator is simple. An ultrasonic actuator converts the ultrasonic mechanical energy to mechanical thrust force by a friction force. Based on this idea, various ultrasonic actuators have been proposed and experimentally constructed. In this paper, the basic characteristics of a piezoelectric actuator are analyzed theoretically. The relationship between the thrust force and the weight force is clarified and verified by experiments. Various prototypes of plane ultrasonic piezoelectric actuators are constructed experimentally, and the fundamental characteristics are measured.     

A Three‐Position Swing Electromagnetic Actuator with an Integrated Eddy Current Brake for Suppression of the Operating Time and Improvement of the Stopping Accuracy

A closed‐loop control system is commonly used in electromagnetic actuators to ensure operating performance. However, this system frequently leads to high costs. We developed a swing electromagnetic actuator with an integrated eddy current brake to reduce the operating time and improve the stopping accuracy. The developed actuator is a three‐position cylindrical actuator moving within a ±120º angle without closed‐loop control. The rotor is composed of a bulk and thin metal laminations and the stator has three sets of pairs of coils. The rotor is stopped at an intermediate position by magnetic force generated by the coils. This paper describes the electromagnetic design and its evaluation by using an FEM simulation to predict its operating characteristics and measure its performance on a test bench. The superiority of our actuator design is verified by comparing these measurements. The operating time is reduced to one‐sixth of that of a laminated rotor and the over travel is compressed to zero. In addition, this actuator has the advantage that it is electrically robust against variations in the power supply.     

A new decentralized retrofit adaptive fault‐tolerant flight control design

In this paper, we develop a new decentralized retrofit adaptive fault‐tolerant control design for a class of nonlinear models arising in flight control. The proposed adaptive fault‐tolerant controller is designed to accommodate loss‐of‐effectiveness (LoE) failures in flight control actuators and achieve accurate estimation of failure‐related parameters. The design is based on local estimation of LoE parameters and generation of local retrofit control signals to accommodate the failures. Using state‐dependent closed‐loop estimation errors, we show the overall system to be stable and demonstrate the tracking error to converge to zero asymptotically for any combination of actuator failures. Through computer simulation of F/A‐18 aircraft under actuator LoE failures, the proposed approach is also shown to achieve better parameter estimation performance compared to the fully centralized design and the design employing local observers and a centralized adaptive controller. Copyright © 2012 John Wiley & Sons, Ltd.     

Operator Based Two Loop Nonlinear Forced Vibration Control of a Flexible Plate

A nonlinear forced vibration control method for a flexible plate with piezoelectric actuators is proposed in this paper. A model of a flexible plate, taking into account the hysteresis of the piezoelectric actuator, is given. In addition, the design of nonlinear control system is given by using the operator theory. Finally, the effectiveness of the proposed nonlinear control system is confirmed by simulation and experimental results.