scholarly journals Control of a gantry crane using input-shaping schemes with distributed delay

2016 ◽  
Vol 39 (3) ◽  
pp. 361-370 ◽  
Author(s):  
MJ Maghsoudi ◽  
Z Mohamed ◽  
MO Tokhi ◽  
AR Husain ◽  
MSZ Abidin
Keyword(s):  
Real Time ◽  
Closed Loop ◽  
Distributed Delay ◽  
Performance Comparison ◽  
Open Loop ◽  
Experimental Results ◽  
Gantry Crane ◽  
Input Shaping ◽  
Position Response ◽  
Sway Frequency

This paper presents simulation and real-time implementation of input-shaping schemes with a distributed delay for control of a gantry crane. Both open-loop and closed-loop input-shaping schemes are considered. Zero vibration and zero vibration derivative input shapers are designed for performance comparison in terms of trolley position response and level of sway reduction. Simulation and experimental results have shown that all the shapers are able to reduce payload sway significantly while maintaining satisfactory position response. Investigations with different cable lengths that correspond to ±20% changes in the sway frequency have shown the distributed delay-based shaper has asymmetric robustness behaviour. The shaper provides highest robustness for the case of 20% increase in the sway frequency but lower robustness for the case of 20% decrease. However, other schemes give symmetric robustness behaviour for both cases.

Performance Comparison between Open Loop and Closed Loop MIMO-OFDM Schemes Using Analytical Approach

2012 ◽  
Vol E95.B (11) ◽  
pp. 3498-3508 ◽  
Author(s):  
Minjee KIM ◽  
Gia Khanh TRAN ◽  
Kei SAKAGUCHI ◽  
Kiyomichi ARAKI
Keyword(s):  
Analytical Approach ◽  
Closed Loop ◽  
Performance Comparison ◽  
Open Loop ◽  
Mimo Ofdm

scholarly journals Generic characterization of electrical test benches for AC- and HVDC-connected wind power plants

2020 ◽  
Vol 5 (2) ◽  
pp. 561-575
Author(s):  
Behnam Nouri ◽  
Ömer Göksu ◽  
Vahan Gevorgian ◽  
Poul Ejnar Sørensen
Keyword(s):  
Real Time ◽  
Wind Power ◽  
Wind Turbines ◽  
Closed Loop ◽  
Short Circuit ◽  
Open Loop ◽  
Device Under Test ◽  
Generic Structure ◽  
Electrical Test ◽  
Grid Connection

Abstract. The electrical test and assessment of wind turbines go hand in hand with standards and network connection requirements. In this paper, the generic structure of advanced electrical test benches, including grid emulator or controllable grid interface, wind torque emulator, and device under test, is proposed to harmonize state-of-the-art test sites. On the other hand, modern wind turbines are under development towards new features, concerning grid-forming, black-start, and frequency support capabilities as well as harmonic stability and control interaction considerations, to secure the robustness and stability of renewable-energy-based power systems. Therefore, it is necessary to develop new and revised test standards and methodologies to address the new features of wind turbines. This paper proposes a generic test structure within two main groups, including open-loop and closed-loop tests. The open-loop tests include the IEC 61400-21-1 standard tests as well as the additional proposed test options for the new capabilities of wind turbines, which replicate grid connection compliance tests using open-loop references for the grid emulator. In addition, the closed-loop tests evaluate the device under test as part of a virtual wind power plant and perform real-time simulations considering the grid dynamics. The closed-loop tests concern grid connection topologies consisting of AC and HVDC, as well as different electrical characteristics, including impedance, short-circuit ratio, inertia, and background harmonics. The proposed tests can be implemented using available advanced test benches by adjusting their control systems. The characteristics of a real power system can be emulated by a grid emulator coupled with real-time digital simulator systems through a high-bandwidth power-hardware-in-the-loop interface.

scholarly journals Design Considerations for Long Term Non-invasive Brain Computer Interface Training With Tetraplegic CYBATHLON Pilot

2021 ◽  
Vol 15 ◽  
Author(s):  
Neethu Robinson ◽  
Tushar Chouhan ◽  
Ernest Mihelj ◽  
Paulina Kratka ◽  
Frédéric Debraine ◽  
...  
Keyword(s):  
Real Time ◽  
Closed Loop ◽  
Brain Computer Interface ◽  
Brain Activation ◽  
Classification Performance ◽  
Open Loop ◽  
Computer Interface ◽  
Single Subject ◽  
User Engagement

Several studies in the recent past have demonstrated how Brain Computer Interface (BCI) technology can uncover the neural mechanisms underlying various tasks and translate them into control commands. While a multitude of studies have demonstrated the theoretic potential of BCI, a point of concern is that the studies are still confined to lab settings and mostly limited to healthy, able-bodied subjects. The CYBATHLON 2020 BCI race represents an opportunity to further develop BCI design strategies for use in real-time applications with a tetraplegic end user. In this study, as part of the preparation to participate in CYBATHLON 2020 BCI race, we investigate the design aspects of BCI in relation to the choice of its components, in particular, the type of calibration paradigm and its relevance for long-term use. The end goal was to develop a user-friendly and engaging interface suited for long-term use, especially for a spinal-cord injured (SCI) patient. We compared the efficacy of conventional open-loop calibration paradigms with real-time closed-loop paradigms, using pre-trained BCI decoders. Various indicators of performance were analyzed for this study, including the resulting classification performance, game completion time, brain activation maps, and also subjective feedback from the pilot. Our results show that the closed-loop calibration paradigms with real-time feedback is more engaging for the pilot. They also show an indication of achieving better online median classification performance as compared to conventional calibration paradigms (p = 0.0008). We also observe that stronger and more localized brain activation patterns are elicited in the closed-loop paradigm in which the experiment interface closely resembled the end application. Thus, based on this longitudinal evaluation of single-subject data, we demonstrate that BCI-based calibration paradigms with active user-engagement, such as with real-time feedback, could help in achieving better user acceptability and performance.

scholarly journals Real-time synthesis of imagined speech processes from minimally invasive recordings of neural activity

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Miguel Angrick ◽  
Maarten C. Ottenhoff ◽  
Lorenz Diener ◽  
Darius Ivucic ◽  
Gabriel Ivucic ◽  
...  
Keyword(s):  
Real Time ◽  
Neural Activity ◽  
Communication Channel ◽  
Closed Loop ◽  
Open Loop ◽  
Depth Electrodes ◽  
Whispered Speech ◽  
Frontal Activity ◽  
Synthesis Approach

AbstractSpeech neuroprosthetics aim to provide a natural communication channel to individuals who are unable to speak due to physical or neurological impairments. Real-time synthesis of acoustic speech directly from measured neural activity could enable natural conversations and notably improve quality of life, particularly for individuals who have severely limited means of communication. Recent advances in decoding approaches have led to high quality reconstructions of acoustic speech from invasively measured neural activity. However, most prior research utilizes data collected during open-loop experiments of articulated speech, which might not directly translate to imagined speech processes. Here, we present an approach that synthesizes audible speech in real-time for both imagined and whispered speech conditions. Using a participant implanted with stereotactic depth electrodes, we were able to reliably generate audible speech in real-time. The decoding models rely predominately on frontal activity suggesting that speech processes have similar representations when vocalized, whispered, or imagined. While reconstructed audio is not yet intelligible, our real-time synthesis approach represents an essential step towards investigating how patients will learn to operate a closed-loop speech neuroprosthesis based on imagined speech.

Analysis of a Novel Single Phase AC-DC CUK Converter with Low Input Current, THD to Improve the Overall Power Quality Using PFC

2018 ◽  
Author(s):  
Shadman Sakib ◽  
Ahmed Jawad Kabir ◽  
Shajal Khansur ◽  
Jewel Rana
Keyword(s):  
Power Factor ◽  
Single Phase ◽  
Closed Loop ◽  
Power Factor Correction ◽  
Performance Comparison ◽  
Open Loop ◽  
Input Current ◽  
Low Input ◽  
Analysis And Design ◽  
Cuk Converter

In this paper, analysis and design of a novel single phase AC-DC CUK converter circuit has been proposed where Power Factor Correction (PFC) controller scheme has been used in order to obtain better performance than conventional converters. Closed loop technique is applied to the bridgeless converter in order to achieve low input current, Total Harmonic Distortion (THD) at input AC mains along with near unity power factor. Performance comparison between open loop and closed loop of the proposed converter is made without filtering. The problems arise with open loop is sufficiently minimized by using power factor correction controller. The performance comparison between proposed and conventional CUK AC-DC converter operating in Continuous Conduction Mode (CCM) is made based on circuit simulations using PSIM softwere.

scholarly journals Autonomous Demand-Side Current Scheduling of Parallel Buck Regulated Battery Modules

Energies ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 2095
Author(s):  
Yunfeng Jiang ◽  
Louis J. Shrinkle ◽  
Raymond A. de Callafon
Keyword(s):  
Energy Storage ◽  
Closed Loop ◽  
Open Circuit ◽  
Open Loop ◽  
Experimental Results ◽  
Battery Pack ◽  
Loop Scheduling ◽  
Load Impedance ◽  
Internal Impedance ◽  
Battery Module

This paper presents the algorithms, hardware overview and testing results for controlling discharge currents from mixed battery modules placed in a parallel configuration. Battery modules with different open-circuit voltage (OCV), internal impedance or even state of charge (SOC) between modules are usually used to form a battery pack. Parallel placed mixed battery modules are typically seen in second-life, repurposed or exchangeable battery systems to increase power and energy storage capacity of a battery pack in mobile, electric vehicle (EV) and stationary energy storage application. This paper addresses battery module heterogeneity by taking advantage of buck regulators on each battery module and formulating scheduling algorithms to dispatch the buck regulators to balance the current out of each battery module. In this way, mixed battery modules can be combined and coordinated to provide a balanced power flow and guarantee safety of the total battery pack. Both open-loop and closed-loop scheduling of buck regulated battery modules are analyzed in this paper. In the open-loop algorithm, buck regulator dispatch commands are computed based on full knowledge of the OCV and impedance of each battery module, while monitoring the load impedance. In the closed-loop algorithm, dispatch commands are generated automatically by a digital proportional-integral-derivative (PID) feedback controller for which battery module current reference signals are computed recursively while monitoring the load impedance. The closed-loop scheduling method is also validated through experimental work that simulates a battery pack with several parallel placed buck regulated battery modules. The experimental results illustrate that the current from each battery module can be rated based on the SOC of each module and that the current remains balanced, despite discrepancies between OCV and internal impedance between modules. The experimental results show that the closed-loop algorithm allows scheduling of buck regulated battery modules, even in the absence of knowledge on the variations of OCV and impedance between battery modules.

A sketch drawing humanoid robot using image-based visual servoing

2019 ◽  
Vol 34 ◽  
Author(s):  
Meng-Cheng Lau ◽  
John Anderson ◽  
Jacky Baltes
Keyword(s):  
Error Correction ◽  
Visual Servoing ◽  
Humanoid Robot ◽  
Closed Loop ◽  
Open Loop ◽  
Experimental Results ◽  
Drawing Process ◽  
Open Loop Control ◽  
Loop Control ◽  
Error Correction Capability

Abstract This paper presents our sketch drawing artist humanoid robot research. One of the limitations of the existing artist humanoid robot is the lack of feedback on the error that occurs during the drawing process. The contribution of this research is the development of a humanoid robot artist with drawing error correction capability. Based on our previous work with open-loop control pen-and-ink humanoid robot artist, we have implemented a closed-loop visual servoing approach to address this problem. Our experimental results show that this approach is sufficient to correct drawing errors that occur due to mechanical limitation of a robot.

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