Real-time feedback control of three-dimensional Tollmien-Schlichting waves using a dual-slot actuator geometry

2018 ◽  
Vol 3 (5) ◽  
Author(s):  
SH. S. Vemuri ◽  
R. Bosworth ◽  
J. F. Morrison ◽  
E. C. Kerrigan
Keyword(s):  
Feedback Control ◽  
Real Time ◽  
Three Dimensional ◽  
Tollmien Schlichting

A Synergy-Based Motor Control Framework for the Fast Feedback Control of Musculoskeletal Systems

2019 ◽  
Vol 141 (3) ◽  
Author(s):  
Reza Sharif Razavian ◽  
Borna Ghannadi ◽  
John McPhee
Keyword(s):  
Motor Control ◽  
Feedback Control ◽  
Real Time ◽  
Three Dimensional ◽  
Muscle Synergies ◽  
Task Space ◽  
Computationally Efficient ◽  
Control Framework ◽  
Muscle Activations ◽  
Musculoskeletal Systems

This paper presents a computational framework for the fast feedback control of musculoskeletal systems using muscle synergies. The proposed motor control framework has a hierarchical structure. A feedback controller at the higher level of hierarchy handles the trajectory planning and error compensation in the task space. This high-level task space controller only deals with the task-related kinematic variables, and thus is computationally efficient. The output of the task space controller is a force vector in the task space, which is fed to the low-level controller to be translated into muscle activity commands. Muscle synergies are employed to make this force-to-activation (F2A) mapping computationally efficient. The explicit relationship between the muscle synergies and task space forces allows for the fast estimation of muscle activations that result in the reference force. The synergy-enabled F2A mapping replaces a computationally heavy nonlinear optimization process by a vector decomposition problem that is solvable in real time. The estimation performance of the F2A mapping is evaluated by comparing the F2A-estimated muscle activities against the measured electromyography (EMG) data. The results show that the F2A algorithm can estimate the muscle activations using only the task-related kinematics/dynamics information with ∼70% accuracy. An example predictive simulation is also presented, and the results show that this feedback motor control framework can control arbitrary movements of a three-dimensional (3D) musculoskeletal arm model quickly and near optimally. It is two orders-of-magnitude faster than the optimal controller, with only 12% increase in muscle activities compared to the optimal. The developed motor control model can be used for real-time near-optimal predictive control of musculoskeletal system dynamics.

Evaluation of the mitral valve by transthoracic real-time three-dimensional echocardiography

2010 ◽  
Vol 151 (21) ◽  
pp. 854-863 ◽  
Author(s):  
Attila Nemes ◽  
Marcel L. Geleijnse ◽  
Osama I. I. Soliman ◽  
Wim B. Vletter ◽  
Jackie S. McGhie ◽  
...  
Keyword(s):  
Mitral Valve ◽  
Real Time ◽  
Three Dimensional ◽  
Dimensional Echocardiography ◽  
Three Dimensional Echocardiography

Jelenleg az echokardiográfia a legszéleskörűbben alkalmazott rutin noninvazív diagnosztikus eljárás, amelynek segítségével a mitralis billentyű morfológiája és funkciója jellemezhető. Ennek az összefoglaló jellegű közleménynek a célja az egyik legújabb echokardiográfiás fejlesztés, a transthoracalis real-time háromdimenziós echokardiográfia szerepének bemutatása a mitralis billentyű vizsgálatában.

A Real-Time Mathematical Model for Three-Dimensional Tidal Flow and Water Quality

1991 ◽  
Vol 24 (6) ◽  
pp. 171-177 ◽  
Author(s):  
Zeng Fantang ◽  
Xu Zhencheng ◽  
Chen Xiancheng
Keyword(s):  
Mathematical Model ◽  
Water Quality ◽  
Real Time ◽  
Control Volume ◽  
Tidal Flow ◽  
Three Dimensional ◽  
River Estuary ◽  
Pearl River Estuary ◽  
Practical Application ◽  
The Pearl River

A real-time mathematical model for three-dimensional tidal flow and water quality is presented in this paper. A control-volume-based difference method and a “power interpolation distribution” advocated by Patankar (1984) have been employed, and a concept of “separating the top-layer water” has been developed to solve the movable boundary problem. The model is unconditionally stable and convergent. Practical application of the model is illustrated by an example for the Pearl River Estuary.

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