Xiaoyuan Luo

Flocking algorithm with multi-target tracking for multi-agent systems

This paper investigates a flocking algorithm with multi-target tracking for multi-agent systems. It is supposed that every target can accept a certain number of agents. Which target is chosen by an agent is determined by the distances from the agent to the targets and the number of agents accepted by targets. Based on whether agents move toward the same target or toward separate targets, two kinds of potential functions are presented to carry out the flocking algorithm. Then the inputs of the dynamic system can be obtained. Under the driving of the inputs, agents with the same target can make a flocking during the tracking process, and the agents with different targets separate from each other. A time-varying parameter is designed to control the maximum velocity of agents in the proposed algorithm. Lyapunov stability theorem is applied to prove the stability of the dynamic system. Finally, simulation results verify the effectiveness of the proposed algorithm.

Distributed formation control for teleoperating cyber-physical system under time delay and actuator saturation constrains

Teleoperating Cyber-Physical System (TCPS) is referred as a new generation of networked teleoperating system. Question of how to enable master operator and slavers to collaborate for sensing and control is largely unexplored. This paper is concerned with a distributed formation control problem for multi-slave TCPS under time delay and actuator saturation constraints. We first develop a min-weighted rigid graph based topology optimization scheme to reduce the redundancy of communication links in slavers, such that the information fusion can be simplified in the formation controller design. The sufficient conditions for stability are presented to show that the formation controllers can stabilize the master-slave TCPS in the presence of time-varying delay and actuator saturation constraints. Finally, to show the validity of our proposed result, both simulations and experiments are performed. It is demonstrated that the topology optimization reduces the redundancy of communication links in slave site at the expense of increased convergence time, while the formation controllers guarantee global asymptotic stability of teleoperation systems subjected to time-varying delay and actuator saturation constraints.

Decentralised control for formation reorganisation of multi-agent systems using a virtual leader

In this article, we study the topology reorganisation of formations for multi-agent systems with a broken agent during motion. The cases with a broken agent in different topologies and different positions are studied, and a decentralised algorithm is proposed to reorganise the different damaged topologies of formations. The main contributions of this article include: first, a collective potential function model is designed to reorganise the topologies, and a repulsive potential function model is proposed to avoid obstacles; second, a decentralised algorithm based on potential functions is presented; third, a virtual agent is designed to be a leader as soon as an agent is damaged, and disappears once the topology is repaired. Finally, some simulation results are studied to demonstrate the efficiency of the proposed algorithm.

Consensus of Multi-slave Bilateral Teleoperation System with Time-Varying Delays

This paper studies the consensus problem for teleoperation system over communication networks. Compared with previous work, both multi-slave configuration and time variable delays are considered. According to the topology structure of slave robots, centralized and distributed consensus controllers are respectively designed, where a leader-following strategy is adopted. During the design process of distributed controllers, min-weighted rigid graph is used to optimize the topology structure of slave robots. With the optimized topology, the amount of communication links and energy dissipations in slave site can be reduced. Moreover, the sufficient stability conditions are presented to show the consensus controllers can stabilize the master-slave system under variable time delay. Finally, simulation results are performed to show the effectiveness of the main results.

Robust exponential stability criteria of uncertain stochastic systems with time-varying delays

This article investigates the problem of delay-dependent exponential stability in mean square for continuous-time linear stochastic systems with structured uncertainties and time-varying delays. By applying descriptor model transformation of the systems, a new type of Lyapunov–Krasovskii functional is constructed, and by introducing some free weighting matrices, some new delay-dependent and delay-independent stability criteria are derived respectively in terms of an LMI algorithm. The new stability criteria are less conservative than existing results. Numerical examples demonstrate that the new criteria are effective and are an improvement over existing results.

Unbiased H ∞ filtering for a class of stochastic systems with time-varying delay

This paper presents the unbiased H∞ filter design for a class of stochastic systems with time-varying delay. The aim is to design an unbiased filter assuring exponential stability in mean square and a prescribed H∞ performance level for the filtering error system. Based on the application of the descriptor model transformation and free weighting matrices, delay-dependent sufficient conditions for stochastic systems with time-varying delay are proposed respectively in terms of linear matrix inequalities(LMIs). Numerical examples demonstrate the proposed approaches are effective and are an improvement over existing methods.

Control of multi-agent formation with optimally persistent graph

In this paper, a distributed control law for optimally persistent formation of leader-follower multi-agent systems is presented. According to the characteristic of optimally persistent formation, each follower, except the one which follows the leader, can only communicate with its two precedent neighbors. Based on the state information received from neighbors, a scalable gradient-like control law is designed to control the motion of the formation. Through using this control law, any three agents that are not in a line can achieve a stable triangular persistent formation. Extend this implementation to the whole formation, thus each agent will keep desired distance constraints to its two precedent neighbors. Finally, simulation examples are illustrated to show the efficiency of the proposed control law.

Method for self-mixing interference signal analysis based on Kalman filter

In this paper, a new signal processing method based on Kalman filter is presented for self-mixing displacement sensor. Based on the approximate linearized model of a LD, the robust Kalman filter is designed for an estimation of system parameters and target displacement. The proposed signal processing algorithm increases the resolution well beyond half-wavelength, without any external optical components, preliminary separate measurements, or target surface preparation. Simulation analysis and experiments have been done to illustrate the validity and the effectiveness of the method. These results show that the displacement estimation is good with little noise and the estimated accuracy of about λ/20 is achievable.