Vibrations are present in many mechanical structures and machines, and are often associated with their elastic parts. Characterizing these vibrations, i.e., obtaining their frequencies, amplitudes and phases, is of most interest in many applications ranging from the maintenance of civil structures to motion control. This paper presents a method for the online and reliable identification of the defining parameters of two unknown sinusoidal signals through the use of their measured sum in the presence of noise and an offset. It is based on the algebraic derivative approach, defined in the frequency domain, which yields exact calculation formulae for the unknown parameters of the signal, i.e., the amplitudes, phases, and frequencies of the two sinusoids and the value of the constant term. The online estimation is performed in a time interval which is only a fraction of the first full cycle of the slower component of the measured signal. This feature allows the algorithm to be used to monitor time-varying parameters in these vibration signals. This algorithm has been used in experiments with a flexible beam, which is a representative platform of a vibrating mechatronic system. It estimated all the vibration signal parameters quickly and accurately, proved to be insensitive to high-frequency noises, and accurately tracked the time variations of the signal parameters.
Last. Han Ding(SJTU: Shanghai Jiao Tong University)H-Index: 29
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In this paper, a general skeleton on modeling, controller design, and applications of the piezoelectric positioning stages is presented. Toward this framework, a general model is first proposed to characterize dynamic behaviors of the stage, including frequency response of the stage, voltage-charge hysteresis and nonlinear electric behavior. To illustrate the validity of the proposed general model, a dynamic backlash-like model is adopted as one of hysteresis models to describe the hysteresis ef...
This paper presents a novel piezoelectric strain sensor for damping and accurate tracking control of a high-speed nanopositioning stage. Piezoelectric sensors have the benefit of simple interface circuitry, low cost, high sensitivity, and high bandwidth. Although piezoelectric sensors have been successfully used as vibration sensors in smart structures, complications arise when they are used in a feedback loop for tracking. As piezoelectric strain sensors exhibit a capacitive source impedance, a...
This study proposes a two-step identification method for estimating the four parameters of a nonlinear model of a position-controlled servomechanism. In the first step, the proposed approach, called the algebraic recursive identification method (ARIM), uses a parametrization derived from the operational calculus currently employed in algebraic identification methods (AIM) recently proposed in the literature. The procedure for obtaining this parametrization eliminates the effect of constant distu...
The amplitude, frequency and phase of a biased and noisy sum of two complex exponential sinusoidal signals are estimated via new algebraic techniques providing a robust estimation within a fraction of the signal period. The methods that are popular today do not seem able to achieve such performances. The efficiency of our approach is illustrated by several computer simulations.
#1Brian J. Kenton(UNR: University of Nevada, Reno)H-Index: 6
#2Kam K. Leang(UNR: University of Nevada, Reno)H-Index: 33
The development of a high-performance three-axis serial-kinematic nanopositioning stage is presented. The stage is designed for high-bandwidth applications that include video-rate scanning probe microscopy and high-throughput probe-based nanofabrication. Specifically, the positioner employs vertically stiff, double-hinged serial flexures for guiding the motion of the sample platform to minimize parasitic motion (runout) and off-axis effects compared to previous designs. Finite element analysis (...
#2Juan R. Trapero(UCLM: University of Castilla–La Mancha)H-Index: 18
Last. Vicente Feliu(UCLM: University of Castilla–La Mancha)H-Index: 32
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This work proposes an adaptive control scheme applied to single link-flexible manipulators, which combines a feedback controller of the joint angle with an adaptive input shaper updated by an algebraic non-asymptotic identification. The feedback controller is designed to guarantee trajectory tracking of the joint angle, simplifying thus the input shaper, which can be designed for the arm dynamics only. The input shaper is updated by an algebraic identification of the natural frequency correspond...
#1Hongxu Wang(Ocean University of China)H-Index: 7
The material theft of steel transmission towers has been an annoying problem in China, which often brings about severe accidents and imperils the entire power system. This paper deals with a feasibility study of utilizing natural frequencies in structural damage identification of steel transmission towers, which are three-dimensional spatial structures. On the basis of the finite element model of a 110 kV self-supporting steel transmission tower, the natural frequency variations between the inta...
In this article, we propose a fast, on-line, algebraic identification scheme for the determination of some relevant induction motor parameters. The estimated values, given by the algebraic identification methodology, are here tested in a self-tuning output feedback control, subject to constant perturbation load torques while solving a reference trajectory tracking task. An output feedback controller of the classical, Field Oriented, Proportional Integral (PI) type, is proposed for the perturbed ...
Last. Heidar Ali Talebi(AUT: Amirkabir University of Technology)H-Index: 31
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In this paper, the problem of attitude control of a 3D nonlinear flexible spacecraft is investigated. Two nonlinear controllers are presented. The first controller is based on dynamic inversion, while the second approach is composed of dynamic inversion and γ-synthesis schemes. The extension of dynamic inversion approach to flexible spacecraft is impeded by the nonminimum phase characteristics when the panel tip position is taken as the output of the system. To overcome this problem, the control...
#2Juan R. Trapero(UCLM: University of Castilla–La Mancha)H-Index: 18
Last. Vicente Feliu(UCLM: University of Castilla–La Mancha)H-Index: 32
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The residual vibrations of highly resonant flexible structures can be usually composed of sinusoidal signals. The identification of the frequencies, amplitudes and/or phases of these sinusoidal signals may be of interest for health monitoring or to update controller parameters in active vibration control systems. This work considers a previously developed algebraic estimator of the frequencies, amplitudes and phases of two sinusoidal signals in order to identify the first two natural frequencies...
Tremor is an uncontrolled trembling movement or shakes, which are defined as an involuntary, rhythmic oscillatory movement of the body. The dominant features of Parkinsonism are the motor task and ...
Last. Vicente Feliu(UCLM: University of Castilla–La Mancha)H-Index: 32
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Parameter uncertainty is a key challenge in the real-time control of nanopositioners employed in scanning probe microscopy. Changes in the sample to be scanned introduces changes in system resonances, requiring instantaneous online tuning of controller parameters to ensure stable, optimal scanning performance. This paper presents a method based on the frequency-domain algebraic derivative approach for the accurate online identification of the nanopositioner's parameters. The parameter estimates ...
#1Zhiyu Ni(CAS: Chinese Academy of Sciences)H-Index: 1
#2Jinguo Liu(CAS: Chinese Academy of Sciences)H-Index: 18
Last. Shen Xinhui(CAS: Chinese Academy of Sciences)H-Index: 1
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Abstract The on-orbit parameter identification of a space structure can be used for the modification of a system dynamics model and controller coefficients. This study focuses on the estimation of a system state-space model for a two-link space manipulator in the procedure of capturing an unknown object, and a recursive tracking approach based on the recursive predictor-based subspace identification (RPBSID) algorithm is proposed to identify the manipulator payload mass parameter. Structural rig...
Last. Yanding Wei(ZJU: Zhejiang University)H-Index: 9
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Auto-regressive moving average with exogenous excitation (ARMAX) model based experimental identification and vibration suppression of a flexible piezoelectric manipulator are conducted. Experimenta...
Abstract This paper proposes a feedback method for the control of uncertain systems with unknown external disturbances, which includes an algebraic estimator and relies on the Active Disturbance Rejection Control (ADRC) approach. The proposed estimator considers a generalized disturbance in order to deal with systems which may simultaneously present time varying parameters, external disturbances, un-modeled dynamics, and process noise. The on-line estimated disturbance is obtained by means of di...
This paper presents experimental identification and vibration suppression of a flexible manipulator with piezoelectric actuators and strain sensors using optimal multi-poles placement control. To precisely identify the system model, a reduced order transfer function with relocated zeros is proposed, and a first-order inertia element is added to the model. Comparisons show the identified model match closely with the experimental results both in the time and frequency domains, and a fit of 97.2% i...
#1Hongzhe Jin(HIT: Harbin Institute of Technology)H-Index: 10
#2Tianlu Wang(HIT: Harbin Institute of Technology)H-Index: 9
Last. Jang-Myung Lee(PNU: Pusan National University)H-Index: 23
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This study presents a new control algorithm based on centrifugal force compensation for balancing unicycle robots, as well as for improving the system's robustness. First, the mechanical structure of the unicycle robot based on gyroscopic precession is built. Second, a new control algorithm based on centrifugal force compensation is developed, whose basic method is to adopt centrifugal force to compensate gyroscopic torque for lateral balance. Third, the effectiveness of the proposed algorithm i...
#1Yanhe Zhu(HIT: Harbin Institute of Technology)H-Index: 16
#2Yongsheng Gao(HIT: Harbin Institute of Technology)H-Index: 9
Last. Jang-Myung Lee(PNU: Pusan National University)H-Index: 12
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This paper presents an adaptive decoupling control strategy for a gyroscopically stabilized pendulum. In the proposed model, the gyro moment acts directly on the pivot of the pendulum, the magnitude of which is restricted by gyroscopic precession. A decoupling algorithm based on virtual control is proposed to regulate the upright posture of the pendulum through gyroscopic precession. Virtual control is considered a control torque that acts on the pivot of the pendulum; it forms nonlinear mapping...
We deal with the online identification of the payload mass carried by a single-link flexible arm that moves on a vertical plane and therefore is affected by the gravity force. Specifically, we follow a frequency domain design methodology to develop an algebraic identifier. This identifier is capable of achieving robust and efficient mass estimates even in the presence of sensor noise. In order to highlight its performance, the proposed estimator is experimentally tested and compared with other c...
