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To meet selective adsorption toward trifluralin, a novel molecularly imprinted polymer (MIP) was fabricated by the dummy template molecular imprinting technology. First, computational simulation was performed to select a suitable dummy template, 3,5‐dinitro‐4‐methylbenzoic acid (T1), based on the maximum basis set superposition error (BSSE)‐corrected binding interaction energy (ΔE) of the monomer N‐vinylpyrrolidone (NVP)‐T1 complex and its structural overlap with trifluralin. Then, the MIP was prepared via the bulk polymerization. The adsorption experiments showed the MIP exhibited a trifluralin adsorption capacity of 5.1 mg g−1, an imprinting factor (IF) of 2.2, and short adsorption equilibrium time of 5 min. The adsorption of trifluralin conformed to the Freundlich adsorption (R2= 0.985) and pseudo‐second‐order model (R2= 0.999). In addition, the MIP exhibited selectivity to trifluralin over other adsorbents, including structural analogs (pendimethalin and oryzalin), pesticide (carbendazim), and nitrocompounds (nitrofurantoin, furazolidone, and furaltadone), with the selectivity factor (β) in the range of 1.2–3.0, respectively. In trifluralin/oryzalin mixture, the IF toward oryzalin was still as high as 1.9. The removal rate of the MIP to trifluralin in environmental water samples ranged from 90.08% to 99.04%. This study provides theoretical and experimental insights for the preparation of MIP using dummy templates.

Strong robustness and smooth speed are two crucial goals of the high-performance permanent magnet synchronous motor (PMSM) drive systems. Conventional active disturbance rejection control (ADRC) strategy generally increases the bandwidth of the extended state observer (ESO) to improve the unsatisfactory disturbance rejection ability, which will inevitably amplify the measurement noise. To address this tough issue, a nonlinear extended state observer (NESO) using finite-time technique is constructed in this article to enhance the anti-disturbance property. On this basis, the NESO with small bandwidth is sufficient to guarantee strong robustness without sacrificing noise suppression performance. Utilizing the frequency-sweep method, the advantages of the proposed NESO-based modified ADRC (MADRC) system can be analyzed in terms of frequency domain characteristics, which is more practical than traditional theoretical analysis from a mathematical point of view. Meanwhile, a quasi-resonant controller is combined with MADRC system to attenuate the main harmonic component of torque ripple for smooth speed. Experimental results are carried out to verify the effectiveness of the proposed control scheme and frequency-sweep analysis method.

To reduce the false positive results caused by cross reactivity of the antibodies with other structural analogues, it is crucial to prepare a high specificity and sensitivity antibody against target for developing an accurate immunoassay. In this study, tilmicosin (TM) was selected as a model molecule. Firstly, two-dimensional similarity, electrostatic potential energy, mulliken atomic charges and overlapping of different haptens with TM were calculated using Gaussian 09W and Discovery studio, and the newly designed TM-HS was selected as the optimal hapten. Furthermore, a monoclonal antibody (mAb 12C8) was produced with the half maximal inhibitory concentration (IC50) of 0.36 ng/mL, and negligible cross-reactivity (CR) with other antibiotics. Finally, a lateral flow immunoassay (LFA) for the detection of TM based on amorphous carbon nanoparticles (ACNPs) labeled mAb 12C8 was developed by the reflectance value under natural light. The recoveries of TM ranged from 83.18% to 103.25% with a coefficient of variation (CV) < 12.47%. The results showed that the cut-off value of TM in milk samples was 1 ng/mL, and the limits of detection (LODs) for chicken muscle, bovine muscle, porcine muscle and porcine liver samples were 5.23, 5.98, 6.85 and 7.31 μg/kg, respectively. In addition, 40 real samples were tested by the LFA, and the detection results were consisted with that of high-performance liquid chromatography-UV detector (HPLC–UV). Those results indicated that the developed LFA is an accurate and useful tool for on-site screening of TM in milk and animal tissues.

Though power electronic interface is prone to higher failure in wind turbine system (WTS), the failure downtime due to mechanical and generator malfunctioning is highest. Unforeseen electromechanical interactions caused due to dynamic load variation and transient torsional stress is a major cause for failures in the drive-train and generator in WTS. In the literature, several techniques, such as generator speed feedback, stress damping controller, and virtual inertia damping controller, have been proposed in regards to the problem stated. Though the techniques are promising, the factor of independent control of natural frequency and damping ratio has not been considered. This paper proposes speed difference damping controller (SDDC), which is a novel and improved control technique that decouples the two above-mentioned parameters and improves the electromechanical performance significantly, reducing the torsional vibration of the driveline. The controller gains are designed based on the derived two-inertia system model that is used to represent the first natural frequency torsional vibration. In this paper, theoretical analysis and control design of SDDC are articulately addressed. A detailed comparative study of SDDC is carried out with respect to the other proposed controllers. The modeled WTS is examined for the first torsional natural frequency under two extreme wind-input conditions, i.e., sinusoidal wind condition, wind impulse, and grid dynamic, and one real-wind test case scenario. For the experimental verification, a multimass test rig operating at the critical speed and dynamic impulse load variation is analyzed in parts.

To avoid false-positive results in immunoassays due to cross-reactivity of antibodies with structural analogues, especially metabolites of target compounds, the preparation of highly specific antibodies is crucial. Preserving the characteristic structure of a target compound when designing a hapten is important when preparing highly specific antibodies. Here, we designed a novel hapten, 4-(((1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4yl)amino)methyl)benzoic acid, named AA-BA, to improve the specificity of antibodies for detection of 4-methylaminoantipyrine (MAA), a residual marker of dipyrone, an important antipyretic-analgesic and anti-inflammatory drug. The structural features of the hapten remained almost the same as those of MAA. After experimental validation, monoclonal antibody 6A4 (mAb 6A4) was prepared with the half maximal inhibitory concentration (IC50) value of 4.03 ng/mL and negligible cross-reactivity with dipyrone metabolites and other antibiotics. In addition, a specific lateral flow immunoassay (LFA) strip based on colloidal gold was developed for screening MAA with a cutoff value of 25 ng/mL in milk. The developed LFA is a useful tool for rapid and accurate detection of MAA.

Abstract In Hard disk drive (HDD) single-stage servo system that uses voice coil motor as the sole actuator, the sensitivity hump appears unavoidable due to the Bode’s integral theorem, resulting in amplification of disturbances at frequencies higher than the open-loop gain crossover frequency. This paper studies the sensitivity transfer function limitation in HDD dual-stage servo system. A compensation method for the micro-actuator dynamics, termed as “near-perfect modeling” (NPM), is proposed to generate an effective compensated plant model with zero relative degree in order to suppress the sensitivity hump of the dual-stage servo loop. Therefore, high-frequency disturbances would not be amplified by the servo loop. Experimental results show that the sensitivity hump of dual-stage servo loop can be reduced to very close to 0 dB without amplification of the corresponding measurement noise.

Abstract This paper is concerned with the seek control of Optical Disk Drives (ODDs). We propose a direct Seek Control Scheme (SCS) that provides fast data access capability and robust stability for high-performance Optical Disk Drives. Although an optical disk drive has a significant advantage of random accessibility, increased rotational speed of a disk and limitations of mechanical structure always make it impossible for the conventional SCS to achieve stable and satisfactory seek performance. The conventional seek control technique utilizes only the coarse actuator without any maneuvering of the fine actuator. In this paper, we analyze the problems that may arise when the conventional SCS is applied to high-speed rotational ODD and propose a new SCS that employs both the coarse and fine actuators. With assistance of the fine actuator, however, the seek control system is designed such that its performance is guaranteed for various disturbances and mechanical limitations. Simulations and experiments show the improvements of the proposed direct SCS implemented on a practical DVD-ROM drive system.

Narrow-band disturbance caused by high speed disk rotation is one of the significant contributors to the track misregistration (TMR) in HDD track following. The peak filter design is an effective control method to suppress the narrow-band disturbance, but the activation of peak filter may produce some oscillations in the output response, which would prolong the settling time of HDD servo system. This paper presents a scheme of state initialization to deal with the undesirable transient response caused by control component. The proposed method is applied to an HDD dual-stage servo system with peak filter design. Testing results demonstrate that the settling performance would not be deteriorated when the high-gain filter is properly initialized. This technique would enhance the disturbance attenuation of HDD dual-stage servo system without the degradation of settling performance.

This paper discusses voltage stability enhancement by a nonlinear Static Var Compensator (SVC) controller. The proposed controller is designed through direct feedback linearization (DFL) technique. The effectiveness of the controller on voltage stability enhancement is studied on a three-machine nine-bus power system. It is found that voltage stability region is expanded significantly by the nonlinear SVC control.

In this paper we investigate a worst-case filtering problem for a class of interconnected uncertain dynamic systems. Interest is focused on the design of decentralized filters which guarantee both robust stability and a prescribed H∞performance in the presence of uncertainties.

In this paper, a general design theory of nonlinear reduced-order observers for the forced nonlinear plants is proposed. Applying this method to reconstruct the power angle δ(t) of a synchronous generator-infinite bus power system, the nonlinear first-order δ^-observer with very simple structure and good performances can be found. The inherent stability region of which is | δ|= 90°. The simulation results of the DFL-LQ optimal exciter (Gao, 1992) with the δ^-oberver show that fast response, good trace ability, wide dynamical stability region, and ideal closed-loop response are all achieved.

This paper is concerned with robust control design for a class of interconnected systems subject to real norm-bounded parameter uncertainty and unknown time delays. We address the problems of decentralized robust stabilization and robust H∞performance. Both decentralized linear dynamic output feedback and static state feedback control laws are investigated. It is shown that these robust control problems can be solved in terms of algebraic Riccati inequalities.

A deterministic linear controller is designed for a linear time invariant system described by a transfer function model based on pole placement. The knowledge required from the unknown system is the bounds of system uncertainties. It is shown that the resulting controller is robust against both structured and unstructured uncertainties and gives an exponentially stable closed-loop feedback system. The internal model principle is included in the controller design to achieve perfect tracking/ disturbance rejection

An H∞controller based on the standard H∞control design approach is proposed for power system load‐frequency control with system parametric uncertainties. The variation bounds of power system parameters are obtained by changing parameters by 30%‐50% simultaneously from their typical values. The existing H∞control technique is applied to design a load‐frequency controller for power systems. The design procedure is given. The proposed H∞controller is simple, effective and can ensure that the overall system is asymptotically stable for all admissible uncertainties. Our simulation results show that for the example system the proposed H∞load‐frequency controller can achieve good performance even in the presence of generation rate constraint.

This paper deals with load–frequency control of a multi‐area power installation. The robust control theory is utilized to decouple the areas for a decentralized robust load–frequency controller. The proposed controller ensures that the overall multi‐area power system is asymptotically stable. A new technique is included to exclude feedback from any immeasurable state. The product comprises a set of local load–frequency controllers, one for each area. The design and operation of each local controller requires solely the corresponding area's parameters and state measurements. Measurements of the immeasurable states are unnecessary. System parameter uncertainties and generation rate constraints are included in the simulation study of a three‐area power system. Good results are reported. Copyright © 1998 John Wiley & Sons, Ltd.

Due to a variety of effects, such as lightning, severe storms and equipment failures, the configuration of an electric power system is not constant. Thus, important parameters, such as effective reactances of transmission lines, in an electric power system always contain some uncertainties. The aim of this paper is to discuss transient stability enhancement and voltage regulation of power systems using feedback linearization techniques and an adaptive control approach. A nonlinear controller design approach is employed to design an adaptive nonlinear control law to prevent the loss of synchronism in a power system under a large sudden fault. An adaptive nonlinear controller is proposed and the stability results for the overall system are established. Simulation results show that transient stability enhancement and voltage regulation of a power system under a large sudden fault can be achieved.

A new robust load-frequency controller using incomplete state feedback is proposed. It is suited for an uncertain power system using reheat type turbines. Such a plant contains system parameter uncertainties and an immeasurable state. The new controller design, based on the Riccati equation approach, considers the bounds of system parameters and feedback gains. Appropriate feedback gains can be chosen from their predefined bounds. This includes the selection of zero-gains for immeasurable states. The new robust controller thus uses incomplete state feedback. No observer is needed. Good performance is reported for an example system.

This paper is concerned with the problems of robust control and robust filtering of a class of discrete-time nonlinear systems with parameter uncertainty. The parameter uncertainty we consider is real time-varying norm-bounded and appears in both the state and output equations. Interest is focused on the design of linear dynamic output feedback controllers and linear filters for the uncertain system and three problems are addressed. The first one is the robust stability analysis and stabiIization whereas the other two problems are the design of controllers and filters to achieve both robust stability and robust performance in an H∞sense. A technique is proposed for the above analysis and synthesis problems by converting them into 'scaled' H∞analysis and control problems which do not involve parameter uncertainty and nonlinearities.

This paper investigates robust output feedback controller design for a class of uncertain dynamical systems with unknown time delays. The uncertainties considered in this paper contain parametric uncertainties, unknown nonlinear functions, unknown time delays and unknown nonlinear functions. The problems of robust stabilization and robust H∞performance are addressed. It is shown that the solutions to the above problems can be obtained from the solutions to algebraic Riccati inequalities. A numerical example indicates that the proposed robust controller can ensure the stability of the overall system.

This paper deals with load–frequency control of a multi-area power installation. The robust control theory is utilized to decouple the areas for a decentralized robust load–frequency controller. The proposed controller ensures that the overall multi-area power system is asymptotically stable. A new technique is included to exclude feedback from any immeasurable state. The product comprises a set of local load–frequency controllers, one for each area. The design and operation of each local controller requires solely the corresponding area's parameters and state measurements. Measurements of the immeasurable states are unnecessary. System parameter uncertainties and generation rate constraints are included in the simulation study of a three-area power system. Good results are reported. Copyright © 1998 John Wiley & Sons, Ltd.