Boundary second-order sliding-mode control of an uncertain heat process with unbounded matched perturbation

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An annotated list of cartilaginous fishes (Chondrichthyes: Elasmobranchii, Holocephali) of the coastal waters of Sakhalin Island and the adjacent southern part of the Sea of Okhotsk

An annotated list of cartilaginous fish (Chondrichthyes: Elasmobranchii, Holocephali) is given for the first time in the 200-year history of studying the ichthyofauna of Sakhalin Island and adjacent waters of the southern part of the Sea of Okhotsk (including the coast of Hokkaido Island) and the northern Sea of Japan. The list includes 43 species in two classes, eight orders, 16 families, and 25 genera. Information on nature conservation status, English and Latin names, depths of habitat, and distribution within the coastal waters of Sakhalin are presented. For a number of species caught off the coast of Sakhalin and in the adjacent waters, information is provided on collection specimens confirming their presence in the region under study. For a number of species of the Rajiformes order (Arctoraja parmifera, A. smirnovi, A. simoterus), the modern ranges and taxonomic status are being refined in the light of new data. The taxonomic status of the so-called “disputed” taxa is discussed as well as the validity of the species considered in the Bathyraja matsubarai complex. Based on the study of the collections, Arctoraja simoterus, previously unknown in the waters of Russia, as well as Myliobatis tobijei, caught in the Bering Sea, has been discovered, which significantly expands the range of this species to the north

Continuous second order sliding mode based finite time tracking of a fully actuated biped robot

International audienceA second order sliding mode controller is modified to form a continuous homogeneous controller. Uniform finite time stability is proved by extending the homogeneity principle of discontinuous systems to the continuous case with uniformly decaying piece-wise continuous nonhomogeneous disturbances. The modified controller is then utilised to track reference trajectories for all the joints of a fully actuated biped robot where the joint torque is modeled as the control input. The modified controller ensures the attainment of a finite settling time between two successive impacts. The main contribution of the paper is to provide straightforward and realizable engineering guidelines for reference trajectory generation and for tuning a robust finite time controller in order to achieve stable gait of a biped in the presence of an external force disturbance. Such a disturbance has destabilising effects in both continuous and impact phases. Numerical simulations of a biped robot are shown to support the theoretical results

Continuous Uniform Finite Time Stabilization of Planar Controllable Systems

Continuous homogeneous controllers are utilized in a full state feedback setting for the uniform finite time stabilization of a perturbed double integrator in the presence of uniformly decaying piecewise continuous disturbances. Semiglobal strong $\mathcal{C}^1$ Lyapunov functions are identified to establish uniform asymptotic stability of the closed-loop planar system. Uniform finite time stability is then proved by extending the homogeneity principle of discontinuous systems to the continuous case with uniformly decaying piecewise continuous nonhomogeneous disturbances. A finite upper bound on the settling time is also computed. The results extend the existing literature on homogeneity and finite time stability by both presenting uniform finite time stabilization and dealing with a broader class of nonhomogeneous disturbances for planar controllable systems while also proposing a new class of homogeneous continuous controllers

APLICACIÓN DE UN REGULADOR H-INFINITO NO LINEAL PARA GRÚA 3D (APPLICATION OF A NONLINEAR H-INFINITY REGULATOR FOR A 3D-CRANE)

ResumenEn este artículo se presenta la solución al problema de estabilizacion de posición robusta ante perturbaciones externas de una grúa a través de un regulador H-infinito no lineal. La grúa bajo estudio en un sistema mecánico subactuado de cinco grados de libertad y tres actuadores que manipulan el movimiento de la cuerda a través de un carro que se mueve en el plano cartesiano. Las posiciones de los actuadores y los ángulos de la cuerda que transporta la carga se pueden medir únicamente mientras que sus velocidades se estiman a través de un filtro H-infinito. Por naturaleza, la carga se encuentra sujeta a perturbaciones externas que se asumen pertenecen al espacio . La solución al problema de control H-infinito por retroalimentación de salida involucra la solución a un par de ecuaciones algebraicas perturbadas de Riccati que evitan hacer la verificación de controlabilidad y detectabilidad del sistema. Los resultados experimentales, realizados en una grúa didáctica, demuestran la factibilidad del método.Palabras claves: Grúa, regulador H-infinito no lineal, robustez.   AbstractIn this paper we present the solution to the robust position stabilization against external disturbances of a crane by using a nonlinear H-infinity regulator. The crane under study is an underactuated mechanical system of five degrees-of-freedom and three actuators that manipulate the rope through a cart moving along the Cartesian space. The position of the cart and the angles of the rope are the only available measurements for feedback while its velocities are estimated by using an H-infinity filter. Typically, the rope is affected by external disturbances which are assumed belong to the  space. The solution of the H-infinity regulator involves the solution of two perturbed algebraic Riccati equations which avoid the verification of the controllability and detectability of the system. The experimental results, made in a laboratory crane, demonstrate the effectiveness of the proposed method.Keywords: Crane, nonlinear H-infinity regulator, robustness