Jian Xu

Tongji University

The directional motion of a continuous worm induced by travelling the mass center of its body is studied in this paper. To this end, a new locomotion gait is constructed to derive the condition that the worm can move forward in one period. The interaction force between the worm body and environment is an anisotropic dry friction. The governing equa...

Worm-like locomotion at small scales induced by propagating a series of extensive or contraction waves has exhibited enormous possibilities in reproducing artificial mobile soft robotics. However, the optimal relation between locomotion performance and some important parameters, such as the distance between two adjacent waves, wave width, and body...

In this paper, a worm-like locomotion in a linear resistive medium is studied to achieve controlled shape changes of the worm-like body by choosing a kind of driving with low energy expended and high-velocity locomotion in certain condition. To this end, we first develop the full dynamic model of the system under consideration to obtain the mean ve...

The present paper mainly focuses on the parameter identification of a vibration absorber coupled with time delay. The absorber is considered to be linear so that its frequency response function can be derived out and corresponding parameter identifiability can be proved conveniently. Using Newton-Raphson procedure, the transcendental frequency resp...

A vibration-driven system is modelled to achieve the expected planar locomotion in the present paper. The system is composed of a main rigid body and two internal and movable masses. Coulomb dry friction and nonholonomic constraint of the body are considered to model stick-slip effect and to ensure the motion without sideslip. It is seen that drivi...

In this paper, some complex phenomena of dynamical bifurcations are shown for a two-neural network with delay coupling. The sigmoid activation function with slope ratio, a monotonically increasing function, is proposed to consider the relations of the sigmoid and Hardlim functions. The equilibrium points are studied analytically in detail in terms...

In the neural system, action potentials play a crucial role in many mechanisms of information communication. The quiescent state, spiking and bursting activities are important biological behaviors with the different neurocomputational properties. In this paper, based on the bifurcation mechanisms involved in the generation of action potentials, an...

Bursting behavior is one of the most important firing activities of neural system and plays an important role in signal encoding and transmission. In the present paper, a neural network with delay coupling is modeled to investigate the generation mechanism of bursting behavior. The Andronov-Hopf bifurcation is firstly studied and then the degenerat...

The time delays in neural networks come from the transformation of the information processing between neurons. To consider delay-induced dynamics in neural networks, the four neurons are coupled to model a called bidirectional associative memory neural network. If the transformation time is distinct in the two direction, then two delays occurs in...

This paper studies the existence and stability of the disease-free equilibrium and endemic equilibria for the SIRS epidemic model with the saturated incidence rate, considering the factor of population dynamics such as the disease-related, the natural mortality and the constant recruitment of population. Analytical techniques are used to show, for...

A continuous-time Hopfield neural network with two delay-connecting neurons is considered in this paper. Some sufficient conditions for the number and delay-independent stability of the equilibria in the network are given analytically. It is necessary to classify the attraction domains since multiple attractors coexist when the sufficient condition...