Yongguang Yu

Stability analysis of fractional-order Hopfield neural networks with time delays

This paper investigates the stability for fractional-order Hopfield neural networks with time delays. Firstly, the fractional-order Hopfield neural networks with hub structure and time delays are studied. Some sufficient conditions for stability of the systems are obtained. Next, two fractional-order Hopfield neural networks with different ring structures and time delays are developed. By studying the developed neural networks, the corresponding sufficient conditions for stability of the systems are also derived. It is shown that the stability conditions are independent of time delays. Finally, numerical simulations are given to illustrate the effectiveness of the theoretical results obtained in this paper.

Leader-follower formation control of nonholonomic mobile robots based on a bioinspired neurodynamic based approach

This paper investigates the leader-follower formation control problem for nonholonomic mobile robots based on a bioinspired neurodynamics based approach. The trajectory tracking control for a single nonholonomic mobile robot is extended to the formation control for multiple nonholonomic mobile robots based on the backstepping technique, in which the follower can track its real-time leader by the proposed kinematic controller. An auxiliary angular velocity control law is proposed to guarantee the global asymptotic stability of the followers and to further guarantee the local asymptotic stability of the entire formation. Also a bioinspired neurodynamics based approach is further developed to solve the impractical velocity jumps problem. The rigorous proofs are given by using Lyapunov theory. Simulations are also given to verify the effectiveness of the theoretical results.

Global stability analysis of fractional-order Hopfield neural networks with time delay

In this paper, the global stability analysis of fractional-order Hopfield neural networks with time delay is investigated. A stability theorem for linear fractional-order systems with time delay is presented. And, a comparison theorem for a class of fractional-order systems with time delay is shown. The existence and uniqueness of the equilibrium point for fractional-order Hopfield neural networks with time delay are proved. Furthermore, the global asymptotic stability conditions of fractional-order neural networks with time delay are obtained. Finally, a numerical example is given to illustrate the effectiveness of the theoretical results. HighlightsThe stability criterion of linear fractional-order systems with time delay is deduced.The existence and uniqueness of equilibrium point for fractional-order time delay neural networks are analyzed.Global stability conditions of fractional-order time delay neural networks are obtained by using Lyapunov method.

Distributed leader-following consensus for second-order multi-agent systems with nonlinear inherent dynamics

In this paper, the leader-following consensus problem for second-order multi-agent systems with nonlinear inherent dynamics is investigated. Two distributed control protocols are proposed under fixed undirected communication topology and fixed directed communication topology. Some sufficient conditions are obtained for the states of followers converging to the state of virtual leader globally exponentially. Rigorous proofs are given by using graph theory, matrix theory and Lyapunov theory. Simulations are also given to verify the effectiveness of the theoretical results.

Distributed consensus-based formation control for multiple nonholonomic mobile robots with a specified reference trajectory

In this paper, the distributed formation control problem for multiple nonholonomic mobile robots using consensus-based approach is considered. A transformation is given to convert the formation control problem for multiple nonholonomic mobile robots into a state consensus problem. Distributed control laws are developed for achieving the formation control objectives: a group of nonholonomic mobile robots at least exponentially converge to a desired geometric pattern with its centroid moving along the specified reference trajectory. Rigorous proofs are provided by using graph, matrix , and Lyapunov theories. Simulations are also given to verify the effectiveness of the theoretical results.

Hopf bifurcation in the Lü system

Abstract In this paper, we use a novel method to investigate the stability of Lu system. It is shown that the Lu system will display a Hopf bifurcation under certain conditions. Finally, we obtain the conditions of supercritical and subcritical bifurcation.

Stability analysis of fractional-order Hopfield neural networks with discontinuous activation functions

Fractional-order Hopfield neural networks are often used to model the information processing of neuronal interactions. For a class of such networks with discontinuous activation functions, it is needed to investigate the existence and stability conditions of their solutions. Under the framework of Filippov solutions, a growth condition is firstly given to guarantee the existence of their solutions. Then, some sufficient conditions are proposed for the boundedness and stability of the solutions of such discontinuous networks by employing the Lyapunov functionals. Finally, a numerical example is presented to demonstrate the effectiveness of the theoretical results. HighlightsFractional-order discontinuous Hopfield neural networks are investigated.A growth condition is given to guarantee the existence of their solutions.A global boundedness condition is presented.A uniqueness condition of the equilibrium point is obtained.A global attractiveness condition is proposed.

Stability Analysis of Fractional-Order Neural Networks with Time Delay

The stability analysis of fractional-order Hopfield neural networks with time delay is investigated. A stability theorem of fractional-order neural networks with time delay is derived. The stability conditions of the two-dimensional fractional-order neural networks with time delay are obtained. Furthermore, the three-dimensional fractional-order neural networks with different ring structures and time delay are proposed, and their stability conditions are derived. To illustrate the effectiveness of our theoretical results, numerical examples and simulations are also presented.

Adaptive distributed formation control for multiple nonholonomic wheeled mobile robots

This paper investigates the adaptive distributed formation control problem for multiple nonholonomic wheeled mobile robots. First, the formation control problem is converted into a state consensus problem by the aid of a variable transformation. Then, distributed kinematic controllers and adaptive dynamic controllers are developed for each robot such that a group of nonholonomic mobile robots asymptotically converge to a desired geometric pattern with its centroid moving along the specified reference trajectory. The specified reference trajectory is assumed to be the trajectory of a virtual leader whose information is available to only a subset of the followers. Also the followers are assumed to have only local interaction. Some sufficient conditions are derived for accomplishing the asymptotically stability of the systems based on algebraic graph theory, matrix theory, and Lyapunov control approach. Finally, simulation examples illustrate the effectiveness of the proposed controllers. HighlightsAdaptive distributed formation control for multiple nonholonomic wheeled mobile robots is investigated.Formation control problem is converted to a state consensus problem via a variable transformation.The specified reference trajectory is assumed to be the trajectory of a virtual leader whose information is available to only a subset of the followers.Distributed kinematic controllers are designed for guaranteeing to reach desired formation.Adaptive dynamic controllers are proposed for guaranteeing mobile robots to track theirs desired kinematic inputs.

Consensus with a reference state for fractional-order multi-agent systems

This paper investigates consensus of fractional-order multi-agent systems (MASs) with a reference state. First, a consensus control law with a constant reference state is given using graph theory and stability analysis of fractional-order. Then, a general control law and a particular one for consensus of fractional-order MASs with a time-varying reference state are proposed. Next, the above control laws are extended to solve formation tracking problem. Finally, several simulations are presented to verify the effectiveness of the obtained results.