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The threshold control theory is applied to build a physiology-based FES controller. The proposed control strategy is tested in simulation study with an integrated musculoskeletal model. The results suggest that the controller based on the threshold control theory alone can realize the task with small feedback delays. However, it is not capable to produce the movement fast enough to match the desired...
A new functional analytic approach to the concept of feedback stabilizability of infinite dimensional linear neutral systems is presented. We first reformulate this systems as an infinite dimensional open-loop systems with appropriate semigroups and unbounded control operators. We introduce conditions for which such semigroups are eventually compact. In addition, when the image of the control operator...
A difference between the human and robots from the viewpoint of motor control is a sampling time in everyday movements. That is, the sampling time for controlling conventional robot systems is required to become approximately 1 ms. On the other hand, the motor control based on human nervous system permits considerably large time-delay due to the transmission latency on afferent/efferent pathways of...
Typical industrial assembly tasks require an accuracy that cannot be realized by only feedback control if a minimum speed is given by a conveyor. Feed-forward has proven to be advantageous, using predictions of the desired trajectory which will be computed from sensor values. These predictions are improved by a model based classification of the sensor data to typical scenarios. In contrast to linear...
This paper deals with an optimal design of linear network based control systems. We study a class of delayed dynamical systems in the continuous time-domain and propose an optimization approach based on the newly elaborated hybrid LQ-type techniques. Moreover, we develop an explicit connection between the given network based control processes and auxiliary hybrid models. The optimal feedback control...
The role of motor control in development of low back pain is subject of many researches both in theoretical and experimental fields. In this work flexion-extension movement of lumbar spine have been controlled by three different methods, including feedback linearization (FBL), PD control and their combinations. The model involves 7 links: 1 link for pelvis, 5 links for lumbar vertebrae and 1 link...
The stabilization of chemostat models with delayed measurements is a challenging problem that is of significant interest in bioengineering and population biology. Here we solve a class of output feedback stabilization problems for chemostat models with one limiting substrate and two species, having Haldane or Monod growth functions. Our stabilizing feedbacks depend only on (i) a given linear combination...
The problem of controlling a modified optically injected semiconductor lasers model is investigated by using theoretical analysis and numerical simulations. Some properties of the three-dimensional chaotic system with higher fractal dimensions are analyzed by using some useful criterions, such as Poincare?? maps and phase portraits. The control parameters are selected based on the delayed feedback...
A new delay-dependent stabilization scheme is provided for a class of linear time-delay (LTD) systems based on proportional-integral-derivative (PID) Hinfin feedback. The time-delay is a differentiable time-varying function satisfying some bounding relations. An appropriate Lyapunov-Krasovskii functional (LKF) is constructed and a new parametrized characterization for proportional-integral-derivative...
A series of convex optimal control problems is proposed as mathematical models of human postural control during quiet standing. The human body is modeled as a two-segment inverted pendulum controlled by a joint torque. Several performance criteria that are quartic in the state and quadratic in the control are utilized. The discrete-time approximation to each of these problems is a convex programming...
Delay co-ordinate feedback (DCF) control may be used to attain periodic oscillations in systems exhibiting low dimensional chaos when measurements of only a single variable are available. This can be achieved by reconstructing the chaotic attractor using time delayed measurements of the variable. In this paper, a modification to the DCF algorithm (2D-DCF) that takes into account sampling rate limitations...
Using Haar wavelets, a computational method is presented to determine the piecewise constant feedback controls for a finite-time linear optimal control problem of a time-varying state-delayed system. The method is simple and computationally advantageous. The approximated optimal trajectory and optimal control are calculated using Haar wavelet integral operational matrix, Haar wavelet product operational...
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