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In this paper the problem of predefined-time exact tracking of fully actuated and unperturbed mechanical systems is solved by means of a continuous controller. It is assumed the availability of the state and the desired trajectory as well as its two first derivatives. This is accomplished introducing the idea of second-order predefined-time stable systems, which is based on the nested application...
This paper proposes the algorithm for flocking of group of nonholonomic mobile robots. Three protocols of smooth potential function are implemented, i.e. flocking, obstacle avoidance, and attracting to goal, as variables of velocity. The main scheme of control of the mobile robots is the use of trajectory tracking which is generated in order to obtain flocking behavior, collision and obstacle avoidance,...
This paper presents the implementations of Model Predictive Control for the standing balance control of a humanoid to reject external disturbances. The strategies allow the robot to have a compliant behaviour against external forces resulting in a stable and smooth response. The first, ZMP based controller, compensates for the center of mass deviation while the second, attitude controller, regulates...
The posture of a humanoid robot needs to be changed from lying state to others in order to complete required missions. With the rolling motion, it is possible for a humanoid robot to change lying state and adapt itself to the environmental uncertainties. The study of rolling motion for humanoid robots is fairly rare. This paper proposed a highly dynamic whole-body rolling motion. The planned rolling...
Linear vapor compressors are becoming more widely utilized in refrigeration applications due to their high efficiency as compared with traditional rotary devices. The nature of the free piston in a linear compressor allows the system resonant frequency to vary with the force of gas compression. In order to ensure efficient operation of the compressor the motor must be excited in such a way as to ensure...
In this paper, we propose a gait transition strategy for a quadruped robot using the Hopf Oscillator model and trajectory planning. The Hopf Oscillator model is used to generate rhythmic moving pattern during trot gait, and trajectory planning based on the Stability Margin (SM) is employed to implement walk gait as well as the transition between walk gait and trot gait. Especially, we develop a moving...
This paper proposes a nonlinear controller that allows the unmanned air vehicle (UAV) to follow a predefined path. The controller only needs the information of the inertial speed of the UAV and the distance between the vehicle and the desired path. In order to improve the performance of the controller, a parameter of the controller is optimized by using the concept of model predictive control (MPC)...
This paper presents an idea to further simplify and relax the linear matrix inequality (LMI) stability conditions of Takagi-Sugeno (T-S) fuzzy systems. By considering the distribution of membership functions in a unified space, we can easily find the overall relation of the original nonlinear system and its approximated local subsystems. Based on the theory of convex combination, the upper-bounds...
This paper proposes conditions for the local stabilization of discrete-time Takagi-Sugeno fuzzy systems, for which all existing conditions consider only global stabilization. The conditions are developed first considering a quadratic Lyapunov function and are then extended for non-quadratic Lyapunov functions. An estimate of the region of attraction is also obtained. The conditions are illustrated...
Synchronous instability may also occur to the P-f droop-controlled voltage source converter as well as virtual synchronous machine during large disturbance, similar to the synchronous generator's synchronous instability in conventional power systems. Moreover, the current limiting link will result in a more complicated instability process and a greatly decreased stability margin of the converter....
This paper presents a combined plant and controller analysis and optimization for a tethered rigid wing with on-board rotors, flying in crosswind patterns. Specifically, we use a 3-D model of the tethered wing to assess the influence of critical design parameters on both quality of flight and energy generation performance, as quantified by the “Loyd Factor” [1], which compares energy generation performance...
Given a linear continuous-time infinite-dimensional plant on a Hilbert space and persistent disturbances of known waveform but unknown amplitude and phase, we show that there exists a stabilizing direct model reference adaptive control law with disturbance rejection and robustness properties. The plant is described by a closed, densely defined linear operator that generates a continuous semigroup...
In this paper, the synchronized output regulation (SOR) problem of leader-following homogeneous linear networked systems aiming at tracking periodical signals is investigated. Only the output information of each agents is delivered throughout the communication network described by undirect graphs. For tracking a general periodic signal consisting of lots of sinusoid functions, the dimension of the...
In this work, we consider nonlinear systems and develop a formulation of Lyapunov-based economic model predictive control (LEMPC) that incorporates actuator magnitude and rate of change constraints on the calculated control actions. Specifically, we formulate LEMPC including maximum and minimum allowable values for the control actions as well as bounds on the differences between the control actions...
In this paper, an algorithm called transverse contracting dynamic system primitive (CDSP) to learn the dynamics of periodic motions from demonstrations is presented. Learning motion plans is essential in making robot programming possible by non-expert programmers as well as realizing human-robot collaboration. The complex periodic motion of the human arm is generated by an orbitally stable closed-loop...
This paper investigates the synthesis of sufficient conditions for finite-time stability of nonlinear quadratic systems. For this purpose, we investigate the usefulness of combining the notion of annihilator with a version of Finsler's Lemma. The design conditions obtained by means of polynomial Lyapunov function are expressed in term of linear matrix inequalities.
This paper deals with the finite-time stability analysis and design problems for Linear Parameter Varying (LPV) systems. First, we extend the concept of the finite-time stability to LPV systems. Then, sufficient conditions for finite-time stability are presented by using Lyapunov-like functions. Moreover, based on the previous finite-time stability analysis, we explore to find the sufficient conditions...
In this paper, a novel sliding-mode-like nonlinear controller is proposed for overhead cranes, which successfully addresses the problem of simultaneously regulating the trolley position and eliminating the payload swing. To be specific, we first transform the original crane model into a quasi-linear form without making any approximations. An elaborately designed manifold is introduced subsequently...
The goal of this paper is to study the switching stabilization of discrete-time autonomous switched linear systems (SLSs) based on the periodic Lyapunov functions. In recent papers, a convex switching stabilizability condition was presented. We investigate properties of the condition. In particular, it is proved that the condition is only a sufficient condition, and also provide a class of stabilizable...
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