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Moment Stability of the Critical Case of PWM Feedback Systems with Stochastic Perturbations

Zhong Zhang, Lixia Ye
2012 Abstract and Applied Analysis  
This paper further studies the moment stability of pulse-width-modulated (PWM) feedback system which is subjected to multiplicative and additive random disturbance modeled by the derivative of Wiener process  ...  We establish several globally asymptotically stability criteria for such PWM feedback systems and then propose an algorithm to calculate the stability bound effectively.  ...  In 20 , the authors established new Lyapunov and Lagrange stability results for pulse-width-modulated PWM feedback systems subjected to random disturbance.  ... 
doi:10.1155/2012/736408 fatcat:osofj3ubffeavazup7fwvqm2si

Optimal control of ankle joint moment: toward unsupported standing in paraplegia

K.J. Hunt, M. Munih, N. Donaldson, F.M.D. Barr
1998 IEEE Transactions on Automatic Control  
In this work our overall objective is to stabilize the subject by stimulation only of his ankle joints while the other joints are braced.  ...  This paper considers part of the problem of how to provide unsupported standing for paraplegics by feedback control.  ...  In our Test , 50 pulses are applied at 1.2-s intervals; they are of ten pulse widths and in random order.  ... 
doi:10.1109/9.679021 fatcat:sevgjolvbnepxlaz5lab5mb4r4

An Algorithm for Network Fluctuation Hopping Signal Suppression Based on Disturbance Characteristics Decomposition and Feed-Forward Modulation

Chen Weijun, Sui Dan
2015 International Journal of Future Generation Communication and Networking  
A feed-forward modulation filter is created to get the feed-forward modulation suppression of the network fluctuation hopping signal.  ...  An algorithm for network fluctuation hopping signal suppression based on disturbance characteristics decomposition and feed-forward modulation is proposed, and the disturbance characteristics decomposition  ...  Acknowledgment On the completion of my thesis, I should like to express my deepest gratitude to all those kindness and advices have made this work possible.  ... 
doi:10.14257/ijfgcn.2015.8.6.06 fatcat:fcqmxsrykvaytgrygdyfxryj2i

Comprehensive Joint Feedback Control for Standing by Functional Neuromuscular Stimulation—A Simulation Study

Raviraj Nataraj, Musa L. Audu, Robert F. Kirsch, Ronald J. Triolo
2010 IEEE transactions on neural systems and rehabilitation engineering  
Feedback gains were optimized to minimize upper extremity (UE) loading required to stabilize against disturbances.  ...  This study assesses the potential efficacy of comprehensive (trunk, hips, knees, and ankles) joint-feedback control against postural disturbances using a bipedal, three-dimensional computer model of SCI  ...  Acknowledgments The authors would like to acknowledge support from the National Institutes of Health (NIH; #R01 NS040547-04A2) and the Motion Study Laboratory at the Louis Stokes Cleveland Veterans Affairs  ... 
doi:10.1109/tnsre.2010.2083693 pmid:20923741 pmcid:PMC3570823 fatcat:7limlkgsc5btvl35gdmovsyagq

Closed-Loop Neural Network-Based NMES Control for Human Limb Tracking

N. Sharma, C. M. Gregory, M. Johnson, W. E. Dixon
2012 IEEE Transactions on Control Systems Technology  
The developed controller is applied as an amplitude modulated voltage to external electrodes attached to the distal-medial and proximallateral portion of the quadriceps femoris muscle group in non-impaired  ...  control, robust integral of the sign of the error (RISE)-based feedback.  ...  For each experiment, the computed voltage input was modulated by a fixed pulse width of 400 s and fixed frequency of 30 Hz.  ... 
doi:10.1109/tcst.2011.2125792 fatcat:ctwdfkhynrdsbgvzclugwakwu4

A neuroprosthesis for control of seated balance after spinal cord injury

Musa L Audu, Lisa M Lombardo, John R Schnellenberger, Kevin M Foglyano, Michael E Miller, Ronald J Triolo
2015 Journal of NeuroEngineering and Rehabilitation  
The mean settling time varied across subjects from 0.5(±0.4) and 2.0 (±1.1) seconds. Mean response time of the feedback control system varied from 393(±38) ms and 536(±84) ms across the cohort.  ...  Results: Preliminary tests in a case series of five subjects show that the controller could maintain trunk stability in the sagittal plane for perturbations up to 45% of body weight and for flexion thresholds  ...  Acknowledgements The authors would like to acknowledge the contributions of our study participant, the Motion Study Laboratory at the Louis Stokes Cleveland Veterans Affairs Medical Center, and the Cleveland  ... 
doi:10.1186/1743-0003-12-8 pmid:25608888 pmcid:PMC4326199 fatcat:zjfuvs4xrrgcjopmlip7jn4utu

Tuning of Pulse-Width Pulse-Frequency Modulator using PSO: An Engineering Approach to Spacecraft Attitude Controller Design

Alireza Khosravi, Pouria Sarhadi
2016 Automatika  
In this paper, a new technique for fine tuning of spacecraft autopilots based on pulse-width pulse-frequency (PWPF) modulators is presented.  ...  PWPF is one of the most commonly used approaches to control signal modulation.  ...  Tuning of Pulse-Width Pulse-Frequency Modulator using PSO: An Engineering Approach... A. Khosravi, P. Sarhadi {r 1 , r 2 } ∈ [0, 1] are also two uniformly distributed random numbers.  ... 
doi:10.7305/automatika.2016.07.618 fatcat:2cx25cajtrhq3mtv2lelhtztiq

Stabilization demands of walking modulate the vestibular contributions to gait

Rina M. Magnani, Sjoerd M. Bruijn, Jaap H. van Dieën, Patrick A. Forbes
2021 Scientific Reports  
AbstractStable walking relies critically on motor responses to signals of head motion provided by the vestibular system, which are phase-dependent and modulated differently within each muscle.  ...  It is unclear, however, whether these vestibular contributions also vary according to the stability of the walking task.  ...  Trial order for the different walking conditions was also randomized for each subject and subjects were given a short 5 min break between trials to limit the influence of any long-term habituation to the  ... 
doi:10.1038/s41598-021-93037-7 pmid:34215780 pmcid:PMC8253745 fatcat:lfmbwxzhfngcbhcskylclplvty

Robust digital autopilot design for spacecraft equipped with pulse-operated thrusters

Sam W. Thurman, Henryk Flashner
1996 Journal of Guidance Control and Dynamics  
or to develop control laws that modulate thruster pulse width or frequency to obtain a quasiproportional response.”  ...  These controllers are designed to approximate a damped, quasilinear systern using pulse-width and pulse-frequency modulation.  ... 
doi:10.2514/3.21744 fatcat:xogdwiqvwfhe3d3lqwkdfdf5ia

Active vibration control of clamped beams using positive position feedback controllers with moment pair

Changjoo Shin, Chinsuk Hong, Weui Bong Jeong
2012 Journal of Mechanical Science and Technology  
The sensor/moment pair actuator which is the non-collocated configuration leads to instability of the control system when using the direct velocity feedback (DVFB) control.  ...  A parametric study of the control system with PPF controller is first conducted to characterize the effects of the design parameters (gain and damping ratio in this paper) on the stability and performance  ...  Acknowledgement This work was partly supported by the 2010 Research Fund of Ulsan College.  ... 
doi:10.1007/s12206-011-1233-y fatcat:ct6o5dwlojfjlasdxe3tl6wey4

Quantum-dot micropillar lasers subject to coherent time-delayed optical feedback from a short external cavity

Steffen Holzinger, Christian Schneider, Sven Höfling, Xavier Porte, Stephan Reitzenstein
2019 Scientific Reports  
do not only expand the understanding of microlasers when subject to optical feedback from short external cavities, but pave the way towards tailoring the properties of this key nanophotonic system for  ...  It is found that the optical pulse can be used to disturb the feedbackcoupled laser within one roundtrip time in such a way that it reaches the same output power as if no feedback was present. our results  ...  Acknowledgements The research leading to these results has received funding from the European Research Council under the European Union's Seventh Framework ERC Grant Agreement No. 615613 and from the German  ... 
doi:10.1038/s41598-018-36599-3 fatcat:7lb56dx455ddtgedyzpg5gssxa

Neurofuzzy adaptive controlling of selective stimulation for FES: a case study

Haiming Qi, D.J. Tyler, D.M. Durand
1999 IEEE transactions on rehabilitation engineering  
The results show that the ANNbased feedforward is capable of predicting 65% of a given desired isometric torque, and the fuzzy logical machine is able to provide suitable gains for feedback modulation  ...  A controller was designed for the selective stimulation of the sciatic nerve with a multiple contact cuff electrode to generate a desired torque in the ankle joint of cat.  ...  torque; CP: current pulse; pa and pw: pulse amplitude and width  ... 
doi:10.1109/86.769409 fatcat:2trhrqbvibhhdlyv3b4qq3f67i

Control of standing balance at leaning postures with functional neuromuscular stimulation following spinal cord injury

Musa L. Audu, Brooke M. Odle, Ronald J. Triolo
2017 Medical and Biological Engineering and Computing  
Feedback control resulted in significant reductions in the mean values of the majority of outcome values compared to baseline open-loop stimulation.  ...  Maximum resultant UE force was reduced by as much as 50% in one of the postures for one of the subjects.  ...  Surface stimulation was delivered at a constant frequency of 20 Hz, with a fixed 100 mA pulse amplitude, and variable pulse-width (PW) up to 250 µs.  ... 
doi:10.1007/s11517-017-1687-x pmid:28736791 pmcid:PMC5790868 fatcat:jnt4azh62ja2xjvxmnggtdv3p4

Unsteady Lift Suppression with a Robust Closed Loop Controller [chapter]

David Williams, Wesley Kerstens, Jens Pfeiffer, Rudibert King, Tim Colonius
2010 Active Flow Control II  
The controller is shown to be capable of significant reductions in lift fluctuations given step, harmonic and random input disturbance conditions.  ...  A 'black box' model of the wing response to actuation is obtained using conventional system identification techniques.  ...  Air Force Office of Scientific Research MURI (FA9550-05-0369) with program manager Dr. Fariba Fahroo is gratefully appreciated.  ... 
doi:10.1007/978-3-642-11735-0_2 fatcat:uzaq3kboevbp7amaz6oqp44gui

Application of reliability-based robust optimization in spacecraft attitude control with PWPF modulator under uncertainties

Vahid Bohlouri, Seyed Hamid Jalali-Naini
2019 Journal of the Brazilian Society of Mechanical Sciences and Engineering  
The single-axis spacecraft attitude is controlled using a combination of the observer-based anti-windup modified PI-D with pulse-width pulse-frequency modulator in the presence of external disturbance.  ...  The input frequency of the thruster is limited to 50 Hz. The uncertain parameters are given as the spacecraft moment of inertia, thrust level, and thruster delay.  ...  The pulse-width pulse-frequency (PWPF) modulator is common in on-off attitude control due to numerous advantages such as high precision, quasilinear behavior, vibration reduction, and low fuel consumption  ... 
doi:10.1007/s40430-019-1955-9 fatcat:sy4zydbcbfg5xhcvf65xc3ezca
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