The Experts below are selected from a list of 11121 Experts worldwide ranked by ideXlab platform
Ronald J. Triolo - One of the best experts on this subject based on the ideXlab platform.
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center of mass Acceleration Feedback control of standing balance by functional neuromuscular stimulation against external postural perturbations
IEEE Transactions on Biomedical Engineering, 2013Co-Authors: Raviraj Nataraj, Musa L. Audu, Ronald J. TrioloAbstract:This study investigated the use of center of mass (COM) Acceleration Feedback for improving performance of a functional neuromuscular stimulation control system to restore standing function to a subject with complete, thoracic-level spinal cord injury. The approach for linearly relating changes in muscle stimulation to changes in COM Acceleration was verified experimentally and subsequently produced data to create an input-output map driven by sensor Feedback. The Feedback gains were systematically tuned to reduce upper extremity (UE) loads applied to an instrumented support device while resisting external postural disturbances. Total body COM Acceleration was accurately estimated (>;89% variance explained) using 3-D outputs of two accelerometers mounted on the pelvis and torso. Compared to constant muscle stimulation employed clinically, Feedback control of stimulation reduced UE loading by 33%. COM Acceleration Feedback is advantageous in constructing a standing neuroprosthesis since it provides the basis for a comprehensive control synergy about a global, dynamic variable and requires minimal instrumentation. Future work should include tuning and testing the Feedback control system during functional reaching activity that is more indicative of activities of daily living.
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Comparing joint kinematics and center of mass Acceleration as Feedback for control of standing balance by functional neuromuscular stimulation.
Journal of neuroengineering and rehabilitation, 2012Co-Authors: Raviraj Nataraj, Musa L. Audu, Ronald J. TrioloAbstract:The purpose of this study was to determine the comparative effectiveness of Feedback control systems for maintaining standing balance based on joint kinematics or total body center of mass (COM) Acceleration, and assess their clinical practicality for standing neuroprostheses after spinal cord injury (SCI). In simulation, controller performance was measured according to the upper extremity effort required to stabilize a three-dimensional model of bipedal standing against a variety of postural disturbances. Three cases were investigated: proportional-derivative control based on joint kinematics alone, COM Acceleration Feedback alone, and combined joint kinematics and COM Acceleration Feedback. Additionally, pilot data was collected during external perturbations of an individual with SCI standing with functional neuromuscular stimulation (FNS), and the resulting joint kinematics and COM Acceleration data was analyzed. Compared to the baseline case of maximal constant muscle excitations, the three control systems reduced the mean upper extremity loading by 51%, 43% and 56%, respectively against external force-pulse perturbations. Controller robustness was defined as the degradation in performance with increasing levels of input errors expected with clinical deployment of sensor-based Feedback. At error levels typical for body-mounted inertial sensors, performance degradation due to sensor noise and placement were negligible. However, at typical tracking error levels, performance could degrade as much as 86% for joint kinematics Feedback and 35% for COM Acceleration Feedback. Pilot data indicated that COM Acceleration could be estimated with a few well-placed sensors and efficiently captures information related to movement synergies observed during perturbed bipedal standing following SCI. Overall, COM Acceleration Feedback may be a more feasible solution for control of standing with FNS given its superior robustness and small number of inputs required.
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Center of mass Acceleration Feedback control of functional neuromuscular stimulation for standing in presence of internal postural perturbations
Journal of rehabilitation research and development, 2012Co-Authors: Raviraj Nataraj, Musa L. Audu, Ronald J. TrioloAbstract:This study determined the feasibility and performance of center of mass (COM) Acceleration Feedback control of a neuroprosthesis utilizing functional neuromuscular stimulation (FNS) to restore standing balance to a single subject paralyzed by a motor and sensory complete, thoracic-level spinal cord injury (SCI). An artificial neural network (ANN) was created to map gain-modulated changes in total body COM Acceleration estimated from body-mounted sensors to optimal changes in stimulation required to maintain standing. Feedback gains were systematically tuned to minimize the upper extremity (UE) loads applied by the subject to an instrumented support device during internally generated postural perturbations produced by volitional reaching and object manipulation. Total body COM Acceleration was accurately estimated (> 90% variance explained) from two three-dimensional (3-D) accelerometers mounted on the pelvis and torso. Compared to constant muscle stimulation employed clinically, COM Acceleration Feedback control of stimulation improved standing performance by reducing the UE loading required to resist internal postural disturbances by 27%. This case study suggests that COM Acceleration Feedback could potentially be advantageous in a standing neuroprosthesis since it can be implemented with only a few Feedback parameters and requires minimal instrumentation for comprehensive, 3-D control of dynamic standing function.
Raviraj Nataraj - One of the best experts on this subject based on the ideXlab platform.
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center of mass Acceleration Feedback control of standing balance by functional neuromuscular stimulation against external postural perturbations
IEEE Transactions on Biomedical Engineering, 2013Co-Authors: Raviraj Nataraj, Musa L. Audu, Ronald J. TrioloAbstract:This study investigated the use of center of mass (COM) Acceleration Feedback for improving performance of a functional neuromuscular stimulation control system to restore standing function to a subject with complete, thoracic-level spinal cord injury. The approach for linearly relating changes in muscle stimulation to changes in COM Acceleration was verified experimentally and subsequently produced data to create an input-output map driven by sensor Feedback. The Feedback gains were systematically tuned to reduce upper extremity (UE) loads applied to an instrumented support device while resisting external postural disturbances. Total body COM Acceleration was accurately estimated (>;89% variance explained) using 3-D outputs of two accelerometers mounted on the pelvis and torso. Compared to constant muscle stimulation employed clinically, Feedback control of stimulation reduced UE loading by 33%. COM Acceleration Feedback is advantageous in constructing a standing neuroprosthesis since it provides the basis for a comprehensive control synergy about a global, dynamic variable and requires minimal instrumentation. Future work should include tuning and testing the Feedback control system during functional reaching activity that is more indicative of activities of daily living.
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Comparing joint kinematics and center of mass Acceleration as Feedback for control of standing balance by functional neuromuscular stimulation.
Journal of neuroengineering and rehabilitation, 2012Co-Authors: Raviraj Nataraj, Musa L. Audu, Ronald J. TrioloAbstract:The purpose of this study was to determine the comparative effectiveness of Feedback control systems for maintaining standing balance based on joint kinematics or total body center of mass (COM) Acceleration, and assess their clinical practicality for standing neuroprostheses after spinal cord injury (SCI). In simulation, controller performance was measured according to the upper extremity effort required to stabilize a three-dimensional model of bipedal standing against a variety of postural disturbances. Three cases were investigated: proportional-derivative control based on joint kinematics alone, COM Acceleration Feedback alone, and combined joint kinematics and COM Acceleration Feedback. Additionally, pilot data was collected during external perturbations of an individual with SCI standing with functional neuromuscular stimulation (FNS), and the resulting joint kinematics and COM Acceleration data was analyzed. Compared to the baseline case of maximal constant muscle excitations, the three control systems reduced the mean upper extremity loading by 51%, 43% and 56%, respectively against external force-pulse perturbations. Controller robustness was defined as the degradation in performance with increasing levels of input errors expected with clinical deployment of sensor-based Feedback. At error levels typical for body-mounted inertial sensors, performance degradation due to sensor noise and placement were negligible. However, at typical tracking error levels, performance could degrade as much as 86% for joint kinematics Feedback and 35% for COM Acceleration Feedback. Pilot data indicated that COM Acceleration could be estimated with a few well-placed sensors and efficiently captures information related to movement synergies observed during perturbed bipedal standing following SCI. Overall, COM Acceleration Feedback may be a more feasible solution for control of standing with FNS given its superior robustness and small number of inputs required.
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Center of mass Acceleration Feedback control of functional neuromuscular stimulation for standing in presence of internal postural perturbations
Journal of rehabilitation research and development, 2012Co-Authors: Raviraj Nataraj, Musa L. Audu, Ronald J. TrioloAbstract:This study determined the feasibility and performance of center of mass (COM) Acceleration Feedback control of a neuroprosthesis utilizing functional neuromuscular stimulation (FNS) to restore standing balance to a single subject paralyzed by a motor and sensory complete, thoracic-level spinal cord injury (SCI). An artificial neural network (ANN) was created to map gain-modulated changes in total body COM Acceleration estimated from body-mounted sensors to optimal changes in stimulation required to maintain standing. Feedback gains were systematically tuned to minimize the upper extremity (UE) loads applied by the subject to an instrumented support device during internally generated postural perturbations produced by volitional reaching and object manipulation. Total body COM Acceleration was accurately estimated (> 90% variance explained) from two three-dimensional (3-D) accelerometers mounted on the pelvis and torso. Compared to constant muscle stimulation employed clinically, COM Acceleration Feedback control of stimulation improved standing performance by reducing the UE loading required to resist internal postural disturbances by 27%. This case study suggests that COM Acceleration Feedback could potentially be advantageous in a standing neuroprosthesis since it can be implemented with only a few Feedback parameters and requires minimal instrumentation for comprehensive, 3-D control of dynamic standing function.
Shirley J. Dyke - One of the best experts on this subject based on the ideXlab platform.
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integrated device placement and control design in civil structures using genetic algorithms
Journal of Structural Engineering-asce, 2005Co-Authors: Ping Tan, Shirley J. Dyke, Andy Richardson, Makola M AbdullahAbstract:One challenge in the application of control systems to civil engineering structures is appropriate integration of a control system into a structure to achieve effective performance. Placement of control devices is strongly linked to the performance of a control system, and the most appropriate device placement scheme is strongly dependent on the performance objectives of the control system. Additionally, for the most effective control system, the placement scheme should be integrated with the design of the controller rather than sequential. This paper proposes an integrated technique to place devices and design controllers based on the use of genetic algorithms. The approach is flexible, allowing the designer to base the placement scheme on performance goals and/or system requirements. Active control devices are used and an H2 ∕LQG controller based on Acceleration Feedback is selected for this study based on previous successes with this approach in civil engineering systems. To illustrate the proposed met...
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seismic control of a nonlinear benchmark building using smart dampers
Journal of Engineering Mechanics-asce, 2004Co-Authors: Osamu Yoshida, Shirley J. DykeAbstract:This paper addresses the third-generation benchmark problem on structural control, and focuses on the control of a full-scale, nonlinear, seismically excited, 20-story building. A semiactive design is developed in which magnetorheological (MR) dampers are applied to reduce the structural responses of the benchmark building. Control input determination is based on a clipped-optimal control algorithm which employs absolute Acceleration Feedback. A phenomenological model of an MR damper, based on a Bouc–Wen element, is employed in the analysis. The semiactive system using the MR damper is compared to the performance of an active system and an ideal semiactive system, which are based on the same nominal controller as is used in the MR damper control algorithm. The results demonstrate that the MR damper is effective, and achieves similar performance to the active and ideal semiactive system, while requiring very little power.
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implementation of an active mass driver using Acceleration Feedback control
Computer-aided Civil and Infrastructure Engineering, 1996Co-Authors: Shirley J. Dyke, B F Spencer, P Quast, D C Kaspari, M K SainAbstract:: Most of the current research on active structural control for aseismic protection has focused on either full-state Feedback strategies or velocity-Feedback strategies. However, accurate measurement of the necessary displacements and velocities of the structure is difficult to achieve directly, particularly during seismic activity. Because accelerometers are inexpensive and can readily provide reliable measurement of the structural Accelerations at strategic points on the structure, development of control methods based on Acceleration Feedback is an ideal solution to this problem. Recent studies of active bracing and active tendon systems have shown that H2/LQG frequency domain control methods employing Acceleration Feedback can be used effectively for aseismic protection of structures. This paper demonstrates experimentally the efficacy of Acceleration-Feedback–based active mass driver (AMD) systems in reducing the response of seismically excited structures.
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Acceleration Feedback control of mdof structures
Journal of Engineering Mechanics-asce, 1996Co-Authors: Shirley J. Dyke, B F Spencer, P Quast, M K Sain, D C Kaspari, T T SoongAbstract:To date, most of the current active structural control strategies for aseismic protection have been based on either full-state Feedback (i.e., all structural displacements and velocities) or on velocity Feedback. However, accurate measurement of displacements and velocities is difficult to achieve directly in full-scale applications, particularly during seismic activity, since the foundation of the structure is moving with the ground. Because accelerometers can readily provide reliable and inexpensive measurement of Accelerations at strategic points on the structure, development of control methods based on Acceleration Feedback is an ideal solution to this problem. The purpose of the present paper is to demonstrate experimentally that Acceleration Feedback-control strategies are effective and robust, and they can achieve performance levels comparable to full-state Feedback controllers.
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Modeling and control of magnetorheological dampers for seismic response reduction
Smart Materials and Structures, 1996Co-Authors: Shirley J. Dyke, Manoj Kumar Sain, J. D. CarlsonAbstract:Control of civil engineering structures for earthquake hazard mitigation represents a relatively new area of research that is growing rapidly. Control systems for these structures have unique requirements and constraints. For example, during a severe seismic event, the external power to a structure may be severed, rendering control schemes relying on large external power supplies ineffective. Magnetorheological (MR) dampers are a new class of devices that mesh well with the requirements and constraints of seismic applications, including having very low power requirements. This paper proposes a clipped-optimal control strategy based on Acceleration Feedback for controlling MR dampers to reduce structural responses due to seismic loads. A numerical example, employing a newly developed model that accurately portrays the salient characteristics of the MR dampers, is presented to illustrate the effectiveness of the approach.
Gunter Niemeyer - One of the best experts on this subject based on the ideXlab platform.
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high frequency Acceleration Feedback in wave variable telerobotics
IEEE-ASME Transactions on Mechatronics, 2006Co-Authors: Neal A Tanner, Gunter NiemeyerAbstract:The human hand is very sensitive to the high-frequency Accelerations produced by tool contact with a hard object, yet most time delayed telerobots neglect this Feedback band entirely in order to achieve stability. We present a control architecture that both incorporates this important information and provides the ability to scale and shape it independently of the low-frequency force Feedback. Leveraging the clean power flows afforded by wave variables, this augmented controller preserves the passivity of any environment that it renders to the user, but is not subject to the limitations of being passive itself. This architecture guarantees stability in the presence of communication delay while achieving a level of Feedback not possible with a passive controller. We show experimentally that this Feedback augmentation and shaping can present a high-frequency Acceleration profile to the user's hand that is similar to that experienced by the slave end effector. Two simple user studies also show that the Feedback augmentation improves the user's perception, performance, and confidence with the given tasks. We anticipate that these natural haptic cues will make teleoperative systems easier to use and thus more widely applicable.
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high frequency Acceleration Feedback in wave variable telerobotics
ASME 2005 International Mechanical Engineering Congress and Exposition, 2005Co-Authors: Neal A Tanner, Gunter NiemeyerAbstract:The human hand is very sensitive to the high frequency Accelerations produced by tool contact with a hard object, yet most time delayed telerobots neglect this Feedback band entirely in order to achieve stability. We present a control architecture that both incorporates this important information and provides the ability to scale and shape it independently of the low frequency force Feedback. Leveraging the clean power flows afforded by wave variables, this augmented controller preserves the passivity of any environment that it renders to the user but is not subject to the limitations of being passive itself. This architecture guarantees stability in the presence of communication delay while achieving a level of Feedback not possible with a passive controller. We show experimentally that this Feedback augmentation and shaping can present a high frequency Acceleration profile to the user’s hand that is similar to that experienced by the slave end effector. We anticipate that these natural haptic cues will make teleoperative systems easier to use and thus more widely applicable.© 2005 ASME
Musa L. Audu - One of the best experts on this subject based on the ideXlab platform.
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center of mass Acceleration Feedback control of standing balance by functional neuromuscular stimulation against external postural perturbations
IEEE Transactions on Biomedical Engineering, 2013Co-Authors: Raviraj Nataraj, Musa L. Audu, Ronald J. TrioloAbstract:This study investigated the use of center of mass (COM) Acceleration Feedback for improving performance of a functional neuromuscular stimulation control system to restore standing function to a subject with complete, thoracic-level spinal cord injury. The approach for linearly relating changes in muscle stimulation to changes in COM Acceleration was verified experimentally and subsequently produced data to create an input-output map driven by sensor Feedback. The Feedback gains were systematically tuned to reduce upper extremity (UE) loads applied to an instrumented support device while resisting external postural disturbances. Total body COM Acceleration was accurately estimated (>;89% variance explained) using 3-D outputs of two accelerometers mounted on the pelvis and torso. Compared to constant muscle stimulation employed clinically, Feedback control of stimulation reduced UE loading by 33%. COM Acceleration Feedback is advantageous in constructing a standing neuroprosthesis since it provides the basis for a comprehensive control synergy about a global, dynamic variable and requires minimal instrumentation. Future work should include tuning and testing the Feedback control system during functional reaching activity that is more indicative of activities of daily living.
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Comparing joint kinematics and center of mass Acceleration as Feedback for control of standing balance by functional neuromuscular stimulation.
Journal of neuroengineering and rehabilitation, 2012Co-Authors: Raviraj Nataraj, Musa L. Audu, Ronald J. TrioloAbstract:The purpose of this study was to determine the comparative effectiveness of Feedback control systems for maintaining standing balance based on joint kinematics or total body center of mass (COM) Acceleration, and assess their clinical practicality for standing neuroprostheses after spinal cord injury (SCI). In simulation, controller performance was measured according to the upper extremity effort required to stabilize a three-dimensional model of bipedal standing against a variety of postural disturbances. Three cases were investigated: proportional-derivative control based on joint kinematics alone, COM Acceleration Feedback alone, and combined joint kinematics and COM Acceleration Feedback. Additionally, pilot data was collected during external perturbations of an individual with SCI standing with functional neuromuscular stimulation (FNS), and the resulting joint kinematics and COM Acceleration data was analyzed. Compared to the baseline case of maximal constant muscle excitations, the three control systems reduced the mean upper extremity loading by 51%, 43% and 56%, respectively against external force-pulse perturbations. Controller robustness was defined as the degradation in performance with increasing levels of input errors expected with clinical deployment of sensor-based Feedback. At error levels typical for body-mounted inertial sensors, performance degradation due to sensor noise and placement were negligible. However, at typical tracking error levels, performance could degrade as much as 86% for joint kinematics Feedback and 35% for COM Acceleration Feedback. Pilot data indicated that COM Acceleration could be estimated with a few well-placed sensors and efficiently captures information related to movement synergies observed during perturbed bipedal standing following SCI. Overall, COM Acceleration Feedback may be a more feasible solution for control of standing with FNS given its superior robustness and small number of inputs required.
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Center of mass Acceleration Feedback control of functional neuromuscular stimulation for standing in presence of internal postural perturbations
Journal of rehabilitation research and development, 2012Co-Authors: Raviraj Nataraj, Musa L. Audu, Ronald J. TrioloAbstract:This study determined the feasibility and performance of center of mass (COM) Acceleration Feedback control of a neuroprosthesis utilizing functional neuromuscular stimulation (FNS) to restore standing balance to a single subject paralyzed by a motor and sensory complete, thoracic-level spinal cord injury (SCI). An artificial neural network (ANN) was created to map gain-modulated changes in total body COM Acceleration estimated from body-mounted sensors to optimal changes in stimulation required to maintain standing. Feedback gains were systematically tuned to minimize the upper extremity (UE) loads applied by the subject to an instrumented support device during internally generated postural perturbations produced by volitional reaching and object manipulation. Total body COM Acceleration was accurately estimated (> 90% variance explained) from two three-dimensional (3-D) accelerometers mounted on the pelvis and torso. Compared to constant muscle stimulation employed clinically, COM Acceleration Feedback control of stimulation improved standing performance by reducing the UE loading required to resist internal postural disturbances by 27%. This case study suggests that COM Acceleration Feedback could potentially be advantageous in a standing neuroprosthesis since it can be implemented with only a few Feedback parameters and requires minimal instrumentation for comprehensive, 3-D control of dynamic standing function.
