Aleksandr Ryzhkov
@sevsu.ru
Digital design
Sevastopol State University
Scopus Publications
Scopus Publications
Aleksandr Bokhonsky, Natalia Varminskaya, Mikhail Maistrishin, and Aleksandr Ryzhkov
ACM
Basing on the generalization of the results for optimal controls designing of the "acceleration-deceleration" type of motion, whence the known special cases follow, universal analytical control function (translational acceleration) was found. Analytically and numerically was confirmed the existence of the limiting minimum control energy at which the movement of an object from the initial state of rest to a new state of rest is possible at a fixed distance and time of motion. Development of models and algorithms for optimal motion control of absolutely rigid and deformable bodies and systems is an urgent task. Basing on the reverse optimality principle (ROP), class of skew-symmetric controls for the translational and rotational motion of elastic systems with a finite and infinite number of degrees of freedom was found. The design of controls, taking into account the target of motion and restrictions, leads to the restoration of the functional criterion, which takes the minimum value during the movement.
Aleksandr Poliakov, Aleksandr Ryzhkov, Marina Kolesova, Petro Shtanko, Pavel Sopin, and Pavel Bugayov
IEEE
This article presents a new design of an active transfemoral prosthesis with an artificial knee joint controlled by a system based on an intellectually-synergetic concept. One of the main criteria used in the prosthesis design process was to achieve the maximum biological similarity of this device with aim to ensure optimal conditions contributing to the user's natural walking. Artificial knee joint, designed on the basis of a polycentric hinged mechanism with intersecting links, provides such conditions at the design level, and a three-level hierarchical control system, built on the basis of an intellectual-synergetic control concept, - at the control level. To recognize user's intentions, the intelligent subsystem uses algorithms of comparing graphic images of walking phases, by the method of Hu's invariant moments estimating. After that, in the synergetic subsystem movements of elements of the prosthetic device are planned in accordance with synergetic quality criteria. All algorithms used in the control system are easily adjustable, depending on what artificial foot is used in the prosthesis: active, semi-active or passive (mechanical). Mathematical modeling of the prosthesis work indicates that the nature of its functioning corresponds to the quality criteria adopted during designing. The key subsystems' work of the prosthesis prototype, made on the basis of digital model, will be investigated in the near future with a specialized test bench.
Aleksandr I. Bokhonsky, Mikhail M. Maistrishin, and Aleksandr I. Ryzhkov
EDP Sciences
One of the simplest types of skew-symmetric optimal controls for the motion of an object as an absolutely rigid and deformable body was theoretically researched and experimentally verified. An elastic system with one degree of freedom was observed as an example, and it was shown, that for an acceptable minimum possible time an absolute rest could be achieved at the end of the motion. The time of motion was found from the system of transcendental equations, which are moment relations in relative motion (relative displacement and relative velocity at the end of translational motion are equal to zero). Experimental test was completed for the optimal translational rotation of the elastic cantilever rod with a distributed mass and the absolute rest was achieved after optimal turning through a predetermined angle (in the shortest possible time) around the axis passing through the end of the rod. Results of the research can find application in: optimal control of the motion of finite stiffness objects in automated production, creation of manipulators of a minimal mass, in the case of mounting non-rigid large-sized structures in outer space, in a number of other areas of modern technologies.