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- Berbyuk, Viktor, 1953
(författare)
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Design of feedback control laws for nonlinear dynamic systems
- 1995
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Ingår i: Proceedings of 3rd European Control Conference. - 9783952417300 ; 2, s. 1488-1491
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Konferensbidrag (refereegranskat)abstract
- A nonlinear dynamic system with restricted controlling forces is considered. A method is developed to design a set of the control laws in the form of a nonlinear feedback that transfer the dynamic system in a finite time from the given initial state to final zero state. The conditions are determined when the proposed method gives possible to design a time-optimal feedback control law. The analytical expression of controlled process duration is found.
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- Berbyuk, Viktor, 1953
(författare)
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Dynamic simulation of a human gait and design problems of the lower limb prostheses
- 1999
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Ingår i: Proceedings of the 12th International Biomechanics Seminar, Ed. C. Högfors, Chalmers, Gothenburg, Sweden, September 10-11, 1999. - 1100-2247. ; XII, s. 1-20
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Konferensbidrag (refereegranskat)abstract
- In this paper the methodology and the numerical algorithm are proposed such as suitable both for the dynamic simulation of a human gait and for solving of the design problems of the lower limb prostheses. The methodology is based on the combination of the optimal control theory and the mathematical modeling with broad utilization of the data obtained from the biomechanical experiments. A special procedure is used for converting the initial optimal control problems for the highly nonlinear and complex bipedal locomotion system into the standard nonlinear programming problems. It is made by approximation of the independent variable functions using the combination of a spline and the Fourier series and the solution of the semi-inverse dynamics problem. The key feature of the algorithm proposed is its high numerical effectiveness and the possibility to satisfy many restrictions imposed on the phase coordinates of the system automatically and accurately. The proposed methodology is illustrated by the computer simulation of a human gait and the numerical results of solution of the design problems of the energy-optimal above-knee prostheses with several types of the structure of the knee mechanisms.
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- Berbyuk, Viktor, 1953
(författare)
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Dynamics and optimal control of biotechnical systems "Man-Prosthesis"
- 1997
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Ingår i: IUTAM Symposium on Interaction Between Dynamics and Control in Advanced Mechanical Systems, Ed. D. van Campen, Kluwer Academic Publishers, 1997. - Dordrecht : Springer Netherlands. ; , s. 35-42
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Konferensbidrag (refereegranskat)abstract
- In the paper, a mathematical model is proposed for investigating the controlled motion of human locomotion system (HLS) with an above-knee prosthesis. To provide insight into the interaction between dynamics and control in biotechnical system Man-Prosthesis the energy optimal control problem of the HLS wearing a lower limb prosthesis has been considered. The algorithm is based on special conversion of the optimal control problem for a nonlinear dynamical system which models HLS into a standard nonlinear programming problem. A number of energy-optimal control problems of human locomotion with an artificial leg, and optimization problems for the constructive parameters of the prostheses under different boundary conditions and constraints have been solved. The numerical results obtained were compared with experimental data for normal human locomotion. The energy-optimal elastic and viscoelastic characteristics of the ankle and knee joints of the prostheses have been determined.
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- Berbyuk, Viktor, 1953, et al.
(författare)
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Effect of the deformability of structural links on the motion of a two-legged walking robot
- 1993
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Ingår i: Journal of Mathematical Sciences. - 1573-8795 .- 1072-3374. ; 65:6, s. 1991-1994
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Tidskriftsartikel (refereegranskat)abstract
- The problems of the dynamics and parametric optimization of the motion of a walking robot are solved within theframework of a seven-link robot's model with the elasticity of the structural components taken into account. The effect of the elasticity of the links on the kinematic, dynamic, and energy characteristics of the locomotion of the walking mechanism is studied.
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- Berbyuk, Viktor, 1953
(författare)
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Energy-optimal control of human leg in swing phase
- 1995
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Ingår i: Biomechanics Seminar. - 1100-2247. ; 9, s. 32-49
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Konferensbidrag (refereegranskat)abstract
- The mathematical model and efficient algorithm for designing the energy-optimal controlled processes of a human leg in the swing phase are proposed. This algorithm is based on special conversion of the optimal control problem for nonlinear dynamical system modeled a human leg into a standard nonlinear programming problem. The objective function for the optimization algorithm is the integral over swing phase's time from the sum of the mechanical power absolute values for all controlling stimuli. A number of the energy-optimal controlled processes of a human leg under different boundary conditions and restrictions on phase coordinates have been obtained. The kinematical and dynamical characteristics of obtained optimal controlled processes are compared with respective characteristics of a human leg's swing phase during normal gait.
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- Berbyuk, Viktor, 1953, et al.
(författare)
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Internal torques of human upper extremity during its optimal motion in vertical plane
- 1997
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Ingår i: The Tenth Biomechanics Seminar. - 1100-2247. ; 10, s. 66-83
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Konferensbidrag (refereegranskat)abstract
- In the paper a number of optimal control problems for the motion of the human upper extremity (HUE), for different types of working tasks, are considered. The performance index used in these problems is the integral over the duration of the working task of the sum of the square of the controlling stimuli acting at the joints of the human arm. Under some conditions this performance index can be used for evaluation of the muscles' energy expenditure during human movements. The HUE is simulated by a plane multibody system of rigid masses. The system comprises the three elements with mass and rotatory inertia modelled the upper arm, the forearm and the hand. The controlled motions of the mechanical system are described in terms of joint angles and Cartesian coordinates of the shoulder joint, through the application of Lagrange's equations. The main aim of the study is an investigation of the interaction between the gravity forces and the internal torques acting at the joints during goal-directed extremal motions of the HUE. The analysis of the internal torques, energetic and viscoelastic characteristics of the shoulder, the elbow and the wrist joints for the exstremal controlled motions of the human arm under the external load acting on the hand has been done.
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