Modeling and optimization of closed-loop retinal motion tracking in scanning light ophthalmoscopy

2019 ◽  
Vol 36 (5) ◽  
pp. 716
Author(s):  
Xinqi Hu ◽  
Qiang Yang
Keyword(s):  
Motion Tracking ◽  
Closed Loop ◽  
Modeling And Optimization ◽  
Retinal Motion

scholarly journals Effects of delayed auditory feedback on gesture-speech synchrony: Pre-registration and exploratory study

2018 ◽  
Author(s):  
Wim T. J. L. Pouw ◽  
James A. Dixon
Keyword(s):  
Pilot Study ◽  
Auditory Feedback ◽  
Motion Tracking ◽  
Closed Loop ◽  
Hand Movement ◽  
Special Kind ◽  
Control Mechanisms ◽  
Delayed Auditory Feedback ◽  
Loop Control ◽  
Motor Pathology

Research on co-speech gestures has shown that gesture-speech synchrony is stable when hand movement or speech is disrupted by a delayed feedback manipulation, suggesting strong bidirectional feedback between gesture and speech. Yet, it has also been argued from case studies in perceptuo-motor pathology, that hand gestures are a special kind of action that do not require closed-loop control mechanisms (e.g., efferent feedback) to function properly in synchrony with speech. In the current pilot study utilizing motion-tracking methods, we reassessed gesture-speech synchrony under conditions of delayed auditory feedback (DAF; 130-150 ms delay) leading to speech disruption. The pilot study indicated that gesture-speech synchrony was indeed stable under DAF, even to a higher degree than the control condition. We also find a promising indication that gesture-speech dynamics does entrain to the external auditory delay as indicated by a consistent shift in gesture-speech synchrony offsets. This pilot study forms the basis for the current pre-registration of a larger-scale study.

Experimental Study of Laser Interferometry Based Motion Tracking of a Flexure-Based Mechanism

2013 ◽  
pp. 165-178
Author(s):  
Umesh Bhagat ◽  
Bijan Shirinzadeh ◽  
Yanling Tian
Keyword(s):  
Experimental Study ◽  
Motion Tracking ◽  
Closed Loop ◽  
Position Control ◽  
Laser Interferometry ◽  
Open Loop ◽  
Closed Loop Control ◽  
Open Loop Control ◽  
Loop Control ◽  
Model Based

This paper presents an experimental study of laser interferometry-based closed-loop motion tracking for flexure-based four-bar micro/nano manipulator. To enhance the accuracy of micro/nano manipulation, laser interferometry-based motion tracking control is established with experimental facility. The authors present and discuss open-loop control, model-based closed-loop control, and robust motion tracking closed-loop control for flexure-based mechanism. A comparative error analysis for closed-loop control with capacitive position sensor and laser interferometry feedback is discussed and presented. Model-based closed-loop control shows improvement in position and motion tracking over open-loop control. Robust control demonstrates high precise and accurate motion tracking of flexure-based mechanism compared to the model-based control. With this experimental study, this paper offers evidence that the laser interferometry-based closed-loop control can minimize positioning and tracking errors during dynamic motion, hence realizing high precision motion tracking and accurate position control.

Mechatronics design for a programmable closed-loop mechanism

2001 ◽  
Vol 215 (3) ◽  
pp. 365-375 ◽  
Author(s):  
W J Zhang ◽  
X B Chen
Keyword(s):  
System Performance ◽  
High Speed ◽  
Motion Tracking ◽  
Closed Loop ◽  
Control Algorithms ◽  
Pd Controller ◽  
Negative Mass ◽  
Mass Redistribution ◽  
Simultaneous Variation ◽  
Shaking Moment

As the demand increases for machines with high accuracy, high speed and high stiffness, programmable closed-loop linkages (PCLL) emerge. This paper presents further results obtained from a study of the mechatronics design approach to PCLL systems proposed by the authors elsewhere. In this approach, the system performances such as motion tracking and torque fluctuation are further improved after a suitable design of mass redistribution. In the present paper it is shown that a scheme called negative mass redistribution, which follows the principle of shaking force/shaking moment balancing, can achieve an excellent improvement in system performance. Furthermore, simultaneous variation in the length of the link and the gain of the PD controller is studied, which shows promise for further improvement in system performance. In general, these studies have shown that complex control algorithms may not achieve a better result than that achieved by a simple PD controller combined with a mass redistribution scheme.

Experimental Study of Laser Interferometry Based Motion Tracking of a Flexure-Based Mechanism

2011 ◽  
Vol 1 (3) ◽  
pp. 31-45 ◽  
Author(s):  
Bijan Shirinzadeh ◽  
Umesh Bhagat ◽  
Yanling Tian
Keyword(s):  
Experimental Study ◽  
Motion Tracking ◽  
Closed Loop ◽  
Position Control ◽  
Laser Interferometry ◽  
Open Loop ◽  
Closed Loop Control ◽  
Open Loop Control ◽  
Loop Control ◽  
Model Based

This paper presents an experimental study of laser interferometry-based closed-loop motion tracking for flexure-based four-bar micro/nano manipulator. To enhance the accuracy of micro/nano manipulation, laser interferometry-based motion tracking control is established with experimental facility. The authors present and discuss open-loop control, model-based closed-loop control, and robust motion tracking closed-loop control for flexure-based mechanism. A comparative error analysis for closed-loop control with capacitive position sensor and laser interferometry feedback is discussed and presented. Model-based closed-loop control shows improvement in position and motion tracking over open-loop control. Robust control demonstrates high precise and accurate motion tracking of flexure-based mechanism compared to the model-based control. With this experimental study, this paper offers evidence that the laser interferometry-based closed-loop control can minimize positioning and tracking errors during dynamic motion, hence realizing high precision motion tracking and accurate position control.

Integrated Design and Control for a Programmable Four-Bar Linkage

1999 ◽  
Author(s):  
Q. Li ◽  
W. J. Zhang ◽  
L. S. Guo
Keyword(s):  
High Speed ◽  
Control Algorithm ◽  
Design Methodology ◽  
Motion Tracking ◽  
Closed Loop ◽  
Controller Design ◽  
Integrated Design ◽  
Dynamic Performances ◽  
And Control ◽  
Four Bar Linkage

Abstract As the demand increases for machines of high accuracy, high speed and high stiffness, programmable closed-loop linkages emerge in the development of modern machinery. A mechatronic design methodology is proposed in this paper for the integrated design of mechanical structure and control algorithm for a programmable closed-loop mechanism system. This design methodology suggests a negative mass redistribution scheme, which follows the principle of a shaking force/shaking moment balancing scheme, for the modification of an existing four-bar mechanism, with the aim to obtain a simple system dynamic model and thus to facilitate controller design. In consequence, motion tracking performance and vibration behavior of the linkage system are significantly improved by simply applying a conventional PD control algorithm. The dynamic performances are further improved by using a model-based controller. The effectiveness of the proposed methodology has been verified by simulation studies.

Improving motion tracking of servomotor-driven closed-loop mechanisms using mass-redistribution

2000 ◽  
Vol 35 (7) ◽  
pp. 1033-1045 ◽  
Author(s):  
Q. Li ◽  
S.K. Tso ◽  
L.S. Guo ◽  
W.J. Zhang
Keyword(s):  
Motion Tracking ◽  
Closed Loop ◽  
Mass Redistribution

Closed Loop Position and Pre-Stress Control for a Morphing Aircraft Wing With Distributed Multi-Axis Pneumatic Actuation

2018 ◽  
Author(s):  
Hongzhao Zhou ◽  
Andrew Plummer ◽  
David Cleaver
Keyword(s):  
Motion Tracking ◽  
Closed Loop ◽  
Position Control ◽  
Shape Change ◽  
Tracking System ◽  
Weight Ratio ◽  
Future Research ◽  
Loop Control ◽  
Active Structure ◽  
Tensegrity Structure

This paper presents the design and control of a morphing wing structure using an active tensegrity structure. A tensegrity structure, which is a set of compressive members (struts) stabilized by a set of tensile members (cables) is a good basis for creating a lightweight active structure, due to its potentially high stiffness-to-weight ratio, and the ease with which actuators can be embedded by replacing selected members in the structure. In this work, a multi-axis control scheme is developed for closed loop control of the shape and internal force (pre-stress) of the structure. An experimental prototype has been built, with 6 unidirectional pneumatic cylinders controlled by pulse-width-modulated switching valves. Shape change in terms of twisting and span-wise bending are demonstrated, and an optical motion tracking system is used to help investigate the dynamic position control of the structure. The structure can achieve ±15° twist change for wing angle of attack or ±10° span-wise bending in a 300mm span length. By simultaneously controlling the structural pre-stress, the geometric stiffness of the structure can also be varied. Future research is discussed, which will involve embedding the active structure in a wing aerofoil and testing in a wind tunnel.

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