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A physiological basis for control of a prosthetic hand

BIOMEDICAL SIGNAL PROCESSING AND CONTROL 2013年第1期8卷 6-15页

作者： Engeberg, Erik D. Univ Akron Auburn Sci & Engn Ctr Akron OH 44325 USA

Recent surveys from upper limb amputees indicate the sentiment that prosthetic hands do not function in a life-like manner and are not intuitively controlled. Thus, two methods of control for a prosthetic hand are presented. A proportional derivative (PD) force controller is compared to a novel biomimetic application of sliding mode control. The biomimetic sliding mode (BSM) controller was designed to map human muscle signals into prosthesis motor command signals in a physiologically expected manner. The BSM and PD controllers were evaluated analytically and subjectively by one amputee and nine nonamputee test subjects. The posture of the hands of the nonamputee test subjects were measured with a CyberGlove and used to determine if the position of the prosthesis (when driven by both controllers) was highly correlated to the posture of the human hands. Force tracking experiments were also performed by all test subjects with both controllers to evaluate the ability to control the applied force. Finally, a dual object lifting task was performed by all test subjects to determine if the mapping of electromyogram (EMG) signals with the BSM controller resulted in physiologically expected motions. A nonparametric Mann-Whitney U-test was performed on the subjective evaluations to determine the statistical significance of the evaluations. The BSM controller was shown to replicate the posture of the human hand much more accurately than the PD force controller. The BSM controller also enabled better average force tracking results and higher success rates with the dual object lifting experiment while the same task was nearly impossible to perform with the PD controller. Finally, the BSM controller was subjectively rated to be more similar to control in comparison to the human hand with respect to position and force. (C) 2012 Elsevier Ltd. All rights reserved.

关键词： Amputee Control systems distributed parameter systems Electromyogram Force control Prosthetic hand

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Optimal control of one-dimensional cellular uptake in tissue engineering

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OPTIMAL CONTROL APPLICATIONS & METHODS 2013年第6期34卷 680-695页

作者： Kishida, Masako Versypt, Ashlee N. Ford Pack, Daniel W. Braatz, Richard D. Univ Illinois Urbana IL USA MIT Cambridge MA 02139 USA

A control problem motivated by tissue engineering is formulated and solved, in which control of the uptake of growth factors (signaling molecules) is necessary to spatially and temporally regulate cellular processes for the desired growth or regeneration of a tissue. Four approaches are compared for determining one-dimensional optimal boundary control trajectories for a distributed parameter model with reaction, diffusion, and convection: (i) basis function expansion, (ii) method of moments, (iii) internal model control, and (iv) model predictive control (MPC). The proposed method of moments approach is computationally efficient while enforcing a nonnegativity constraint on the control input. Although more computationally expensive than methods (i)-(iii), the MPC formulation significantly reduced the computational cost compared with simultaneous optimization of the entire control trajectory. A comparison of the pros and cons of each of the four approaches suggests that an algorithm that combines multiple approaches is most promising for solving the optimal control problem for multiple spatial dimensions. Copyright (c) 2012 John Wiley & Sons, Ltd.

关键词： stem cell tissue engineering tissue engineering systems biology distributed parameter systems partial differential equations boundary control

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SAMPLED-DATA distributed H_∞ CONTROL OF TRANSPORT REACTION systems

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SIAM JOURNAL ON CONTROL AND OPTIMIZATION 2013年第2期51卷 1500-1527页

作者： Fridman, Emilia Bar Am, Netzer Tel Aviv Univ Sch Elect Engn IL-69978 Tel Aviv Israel

We develop, for the first time, sampled-data distributed H-infinity control of a class of parabolic systems. These systems are governed by one-dimensional semilinear transport reaction equations with additive disturbances. A network of stationary sensing devices provides spatially averaged state measurements over the N sampling spatial intervals. We suggest a sampled-data controller design, where the sampling intervals in time and in space are bounded. Our sampled-data static output feedback enters the equation through N shape functions (which are localized in the space) multiplied by the corresponding state measurements. Sufficient conditions for the internal exponential stability and for L-2-gain analysis of the closed-loop system are derived via direct Lyapunov method in terms of linear matrix inequalities (LMIs). By solving these LMIs, upper bounds on the sampling intervals that preserve the internal stability and the resulting L-2-gain can be found. Numerical examples illustrate the efficiency of the method.

关键词： sampled-data control H-infinity control distributed parameter systems Lyapunov method linear matrix inequalities

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Novel location algorithm for single-line-to-ground faults in transmission line with distributed parameters

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IET GENERATION TRANSMISSION & DISTRIBUTION 2013年第6期7卷 560-566页

作者： Wang, Bin Dong, Xinzhou Lan, Lan Xu, Fei Tsinghua Univ Dept Elect Engn State Key Lab Control & Simulat Power Syst & Gene Beijing 100084 Peoples R China

Precise fault location (FL) is definitely important for fast fault clearance and restoration of energy transmission. The single-terminal FL is mostly met in applications because of its easy implementation, but the accuracies of all-type impedance FL algorithms are not good because of the effects of fault resistance and variation of an opposite terminal equivalent system impedance. The recently developed and assembled FL algorithm presented in this study, combining the stability of the impedance FL and precision of the travelling waves FL, is an expected good solution. However, the key point to achieve accurate FL is to naturally couple these two algorithms. As is known, the distributed parameters model is also the research base of these two algorithms. Hence, the impedance FL algorithm in line with distributed parameters is proposed in this study. It is achieved on the discovery that the negative sequence current at relay location maintains precisely the same phase to the voltage at fault point. The proposed algorithm is immune to shunt capacitance because of modelling with distributed parameters, and is not disturbed by ground resistance when calculated at zero-crossing moment of voltage at fault point. Simulations and tests prove its good performance.

关键词： fault resistance effect power transmission faults travelling wave FL power system restoration single-line-to-ground fault Power transmission, distribution and supply earthing Power system management, operation and economics opposite terminal equivalent system impedance distributed parameter systems Power system protection fault location Power system control zero-crossing moment calculation fault restoration single-terminal FL algorithm energy transmission line ground resistance all-type impedance FL algorithm precise fault location algorithm distributed parameter model negative sequence current relay location shunt capacitance fault clearance transmission line power system stability power transmission lines

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distributed adaptive consensus tracking of a class of networked non-linear systems with parametric uncertainties

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IET CONTROL THEORY AND APPLICATIONS 2013年第7期7卷 1049-1057页

作者： Yoo, Sung Jin Chung Ang Univ Sch Elect & Elect Engn Seoul 156756 South Korea

This study investigates a distributed adaptive consensus tracking problem for multiple non-linear strict-feedback systems with parametric uncertainties under a directed communication graph topology. It is assumed that the information of a leader is available for only a limited subset of followers. The distributed adaptive dynamic surface design approach is presented to design the local controller of each follower to guarantee that all networked followers with unmatched parametric uncertainties synchronise to the leader regardless of a lack of the shared information on the communication links. From the Lyapunov stability theorem, it is shown that the consensus tracking errors are cooperatively semiglobally uniformly ultimately bounded and converge to an adjustable neighbourhood of the origin.

关键词： multiagent systems distributed cooperative control directed communication graph topology adaptive control local controller design distributed adaptive consensus tracking problem Combinatorial mathematics multiple nonlinear strict-feedback systems stability control system synthesis synchronisation Stability in control theory Control system analysis and synthesis methods Nonlinear control systems networked control systems multi-robot systems feedback Self-adjusting control systems Lyapunov methods nonlinear control systems convergence unmatched parametric uncertainties uncertain systems directed graphs distributed parameter systems tracking networked nonlinear systems mobile robots distributed adaptive dynamic surface design Lyapunov stability theorem distributed parameter control systems Mobile robots communication links

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Adaptive sliding manifold slope via grasped object stiffness detection with a prosthetic hand

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MECHATRONICS 2013年第8期23卷 1171-1179页

作者： Andrecioli, Ricardo Engeberg, Erik D. Univ Akron Dept Mech Engn Akron OH 44325 USA Univ Akron Dept Biomed Engn Akron OH 44325 USA

Upper limb amputees have expressed the desire for their prosthetic hands to better adapt to the parameters of different grasped objects. In response to this need, an adaptive sliding mode controller (ASMC) is developed that has a variable-slope manifold which is dependent upon the stiffness of the grasped object. The ASMC is experimentally compared to a sliding mode controller (SMC) which has a constant manifold slope over a wide range of grasped object stiffness, ranging from an empty hand to a steel bar. Experimental results indicate that both controllers have satisfactory percent overshoot characteristics;however, the ASMC has significantly less absolute error for all experiments performed with eight different levels of grasped object stiffness. (C) 2013 Elsevier Ltd. All rights reserved.

关键词： Sliding mode control Prosthetic hand Amputee Adaptive control distributed parameter systems

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Observers and initial state recovering for a class of hyperbolic systems via Lyapunov method

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AUTOMATICA 2013年第7期49卷 2250-2260页

作者： Fridman, Emilia Tel Aviv Univ Sch Elect Engn IL-69978 Tel Aviv Israel

Recently the problem of estimating the initial state of some linear infinite-dimensional systems from measurements on a finite interval was solved by using the sequence of forward and backward observers Ramdani, Tucsnak, and Weiss (2010). In the present paper, we introduce a direct Lyapunov approach to the problem and extend the results to the class of semilinear systems governed by wave and beam equations with boundary measurements from a finite interval. We first design forward observers and derive Linear Matrix Inequalities (LMIs) for the exponential stability of the estimation errors. Further we obtain simple finite-dimensional conditions in terms of LMIs for an upper bound T* on the minimal time, that guarantees the convergence of the sequence of forward and backward observers on [0, T*] for the initial state recovering. This T* represents also an upper bound on the observability time. For observation times bigger than T*, these LMIs give upper bounds on the convergence rate of the iterative algorithm in the norm defined by the Lyapunov functions. In our approach, T* is found as the minimal dwelling time for the switched exponentially stable (forward and backward estimation error) systems with the different Lyapunov functions (Liberzon, 2003). The efficiency of the results is illustrated by numerical examples. (C) 2013 Elsevier Ltd. All rights reserved.

关键词： distributed parameter systems Observers Lyapunov method LMIs Switched systems

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CONFIGURING A SENSOR NETWORK FOR FAULT DETECTION IN distributed parameter systems

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INTERNATIONAL JOURNAL OF APPLIED MATHEMATICS AND COMPUTER SCIENCE 2008年第4期18卷 513-524页

作者： Patan, Maciej Ucinski, Dariusz Univ Zielona Gora Inst Control & Computat Engn PL-65246 Zielona Gora Poland

The problem of fault detection in distributed parameter systems (DPSs) is formulated as that of maximizing the power of a parametric hypothesis test which checks whether or not system parameters have nominal values. A computational scheme is provided for the design of a network of observation locations in a spatial domain that are supposed to be used while detecting changes in the underlying parameters of a distributed parameter system. The setting considered relates to a situation where from among a finite set of potential sensor locations only a subset can be selected because of the cost constraints. As a suitable performance measure, the D-s-optimality criterion defined on the Fisher information matrix for the estimated parameters is applied. Then, the solution of a resulting combinatorial problem is determined based on the branch-and-bound method. As its essential part, a relaxed problem is discussed in which the sensor locations are given a priori and the aim is to determine the associated weights, which quantify the contributions of individual gauged sites. The concavity and differentiability properties of the criterion are established and a gradient projection algorithm is proposed to perform the search for the optimal solution. The delineated approach is illustrated by a numerical example on a sensor network design for a two-dimensional convective diffusion process.

关键词： branch-and-bound constrained experimental design distributed parameter systems fault detection parameter estimation sensor location

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A Strict Control Lyapunov Function for a Diffusion Equation With Time-Varying distributed Coefficients

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IEEE TRANSACTIONS ON AUTOMATIC CONTROL 2013年第2期58卷 290-303页

作者： Argomedo, Federico Bribiesca Prieur, Christophe Witrant, Emmanuel Bremond, Sylvain UJF Univ Grenoble CNRS GIPSA LabUMR 5216 F-38402 Grenoble France CEA F-13108 St Paul Les Durance France

In this paper, a strict Lyapunov function is developed in order to show the exponential stability and input-to-state stability (ISS) properties of a diffusion equation for nonhomogeneous media. Such media can involve rapidly time-varying distributed diffusivity coefficients. Based on this Lyapunov function, a control law is derived to preserve the ISS properties of the system and improve its performance. A robustness analysis with respect to disturbances and estimation errors in the distributed parameters is performed on the system, precisely showing the impact of the controller on the rate of convergence and ISS gains. This is important in light of a possible implementation of the control since, in most cases, diffusion coefficient estimates involve a high degree of uncertainty. An application to the safety factor profile control for the Tore Supra tokamak illustrates and motivates the theoretical results. A constrained control law (incorporating nonlinear shape constraints in the actuation profiles) is designed to behave as close as possible to the unconstrained version, albeit with the equivalent of a variable gain. Finally, the proposed control laws are tested under simulation, first in the nominal case and then using a model of Tore Supra dynamics, where they show adequate performance and robustness with respect to disturbances.

关键词： distributed parameter systems fusion power generation Lyapunov method partial differential equations time-varying systems tokamaks

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Bioinspired Sinusoidal Finger Joint Synergies for a Dexterous Robotic Hand to Screw and Unscrew Objects With Different Diameters

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IEEE-ASME TRANSACTIONS ON MECHATRONICS 2013年第2期18卷 612-623页

作者： Karnati, Nareen Kent, Benjamin A. Engeberg, Erik D. Univ Akron Dept Mech Engn Akron OH 44325 USA

This paper addresses the complex task of unscrewing and screwing objects with a dexterous anthropomorphic robotic hand in two cases: with the first finger and thumb and also with the little finger and thumb. To develop an anthropomorphic solution, human finger synergies from nine test subjects were recorded while unscrewing and screwing a threaded cap. Human results showed that the periodic motions exhibited by the finger joints shared a common frequency for each subject, but differed in amplitude and phase. From the gathered data, a set of sinusoidal trajectories were developed to approximate this motion for application to a robotic hand. Because the joint trajectories exhibited the same frequency, a family of sinusoids that share a common time vector can be used in the path planning of the robotic hand to unscrew and screw objects. Additionally, the human unscrewing data are highly similar to the mirror image of the screwing data. This chiastic trait enables screwing to be performed by decreasing the time vector;increasing the time vector produces unscrewing. These factors significantly reduce the computational cost and complexity of the task. Cartesian and joint space error analyses show that the developed sinusoidal trajectories closely mimic the motion profiles seen in the human experiments. Furthermore, this bioinspired sinusoidal solution is extended to objects with wide variations in diameters by relating joint angle offsets of the robotic hand to object diameter size through the forward kinematics equations. The sinusoidal trajectories are all implemented within a PID sliding mode controller for a dexterous artificial hand to ensure overall system stability. Using the bioinspired sinusoidal joint angle trajectories, the robotic hand successfully unscrewed and screwed four different objects in all trials conducted with each object diameter size.

关键词： Dexterous hand distributed parameter systems grasp synergy prosthetic hand sliding mode control

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