Jet Mode Recognition of Electrohydrodynamic Direct-Writing Based on Micro/Nano Current

The online recognition of jet mode is important for the accurate control and further application of electrohydrodynamic direct-writing (EDW) technology. An EDW system with a current detection module is built for jet mode recognition. The current of the EDW jet is measured to recognize the jet mode when printing patterned structures. Then, a data processing program with a digital Kaiser low-pass filter is developed in MATLAB, via which the noise of the current signal is reduced. The features of EDW current, including the current fluctuation and the peak current intervals, are studied to recognize different jet modes. The current characteristics of three jet modes are investigated: droplet ejection mode, Taylor cone ejection mode, and retractive ejection mode. The Taylor cone ejection mode has the smallest coefficient of variation of peak current. This work provides a good way of designing the optimized control algorithm and of realizing the closed-loop control system, which contributes to enhancing the jet stability and accelerating the application of EDW technology.

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Dynamic modelling and open-loop control of a twin rotor multi-input multi-output system

Proceedings of the Institution of Mechanical Engineers Part I Journal of Systems and Control Engineering ◽

10.1177/095965180221600604 ◽

2002 ◽

Vol 216 (6) ◽

pp. 477-496 ◽

Cited By ~ 13

Author(s):

S M Ahmad ◽

A J Chipperfield ◽

M O Tokhi

Keyword(s):

Mimo System ◽

Dynamic Modelling ◽

Open Loop ◽

Open Loop Control ◽

Performance Study ◽

Pass Filter ◽

Low Pass Filter ◽

Loop Control ◽

Low Pass ◽

Twin Rotor

A dynamic model for a one-degree-of-freedom (DOF) twin rotor multi-input multi-output (MIMO) system (TRMS) in hover is obtained using a black-box system identification technique. The behaviour of the TRMS in certain aspects resembles that of a helicopter; hence, it is an interesting identification and control problem. This paper investigates modelling and open-loop control of the longitudinal axis alone, while the lateral axis movement is physically constrained. It is argued that some aspects of the modelling approach presented are suitable for a class of new generation or innovative air vehicles with complex dynamics. The extracted model is employed for designing and implementing a feedforward/open-loop control. Open-loop control is often the preliminary step for development of more complex feedback control laws. Open-loop control strategies using shaped command inputs are accordingly investigated for resonance suppression in the TRMS. Digital low-pass and band-stop filter shaped inputs are used on the TRMS testbed, based on the identified vibrational modes. A comparative performance study is carried out and the corresponding results presented. The low-pass filter is shown to result in better vibration reduction.

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Current-source 1-Ph inverter design for aircraft applications

Aircraft Engineering and Aerospace Technology ◽

10.1108/aeat-10-2019-0194 ◽

2020 ◽

Vol 92 (8) ◽

pp. 1295-1305

Author(s):

Eralp Sener ◽

Gurhan Ertasgin

Keyword(s):

Pulse Width Modulation ◽

High Efficiency ◽

Current Source ◽

Sine Wave ◽

Constant Current ◽

Constant Current Source ◽

Pass Filter ◽

Low Pass Filter ◽

Content Type ◽

Loop Control

Purpose This paper aims to present an inverter with a current-source input for 400 Hz avionic systems to have a system which removes DC-link capacitors and presents a high efficiency. Design/methodology/approach A battery-powered DC link inductor generates a constant-current source. A single high-frequency switch is used to provide a sinusoidally modulated current before the inverter. The output of the switch is “unfolded” by a thyristor-based H-bridge inverter to generate an AC output current. The system uses a CL low-pass filter to obtain a 400 Hz pure sine wave by removing pulse width modulation components. Findings Simulations and Typhoon HIL real-time experiments were performed with closed-loop control to validate the proposed inverter concept while meeting the critical standards of MIL-STD-704F. Originality/value This current source inverter topology is suitable for avionic systems that require 400 Hz output frequency. The topology uses small DC-link inductor and eliminates bulky capacitor which determines the inverter lifetime.

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Sensorless Control of PMSM with Compensated Sliding Mode Observer

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.241-244.1226 ◽

2012 ◽

Vol 241-244 ◽

pp. 1226-1233

Author(s):

Zi You Song ◽

Jian Qiu Li ◽

Ming Gao Ouyang ◽

Liang Fei Xu ◽

Jun Ming Hu

Keyword(s):

Closed Loop ◽

Sliding Mode ◽

Sensorless Control ◽

Hall Sensor ◽

Sliding Mode Observer ◽

Closed Loop Control ◽

Pass Filter ◽

Low Pass Filter ◽

Loop Control ◽

Rotary Speed

This paper presents a research on sensorless control of Permanent-magnet Synchronous Motor (PMSM) based on a compensated sliding mode observer (C-SMO) using one Hall sensor. Generally the sliding mode observer (SMO) has an attractive robustness to disturbances, and parameter variations in relatively high speed region. But the SMO cannot help reducing the ripple or chattering components of the estimated currents and the estimated phase especially in the low speed region. The estimated rotary speed is the differential result of the estimated phase. So the noise of the estimated phase is amplified in the estimated rotary speed which is used in speed closed-loop control and the low pass filter. The PMSM cannot be started with traditional SMO under closed-loop control condition. A more accurate estimated speed and a phase reference may solve this problem and they can be estimated by the Hall sensor. This more accurate estimated speed can also help the PMSM achieve a better performance on rotor phase estimation. The C-SMO which combines the advantages of Hall sensor and SMO achieves a less noise, less vibration effect. And the PMSM can be started with C-SMO under closed-loop control condition. The comparison between the SMO and C-SMO is realized by Matlab/Simulink and the simulation results show the effectiveness of the proposed algorithm for the sensorless drive system of a PMSM.

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