Cooperative adaptive control for synchronization of second‐order systems with unknown nonlinearities

This paper studies synchronization to a desired trajectory for multi‐agent systems with second‐order integrator dynamics and unknown nonlinearities and disturbances. The agents can have different dynamics and the treatment is for directed graphs with fixed communication topologies. The command generator or leader node dynamics is also nonlinear and unknown. Cooperative tracking adaptive controllers are designed based on each node maintaining a neural network parametric approximator and suitably tuning it to guarantee stability and performance. A Lyapunov‐based proof shows the ultimate boundedness of the tracking error. A simulation example with nodes having second‐order Lagrangian dynamics verifies the performance of the cooperative tracking adaptive controller. Copyright © 2010 John Wiley & Sons, Ltd.     

Information fusion for automotive applications – An overview

This article focusses on the fusion of information from various automotive sensors like radar, video, and lidar for enhanced safety and traffic efficiency. Fusion is not restricted to data from sensors onboard the same vehicle but vehicular communication systems allow to propagate and fuse information with sensor data from other vehicles or from the road infrastructure as well. This enables vehicles to perceive information from regions that are hardly accessible otherwise and represents the basis for cooperative driving maneuvers. While the Bayesian framework builds the basis for information fusion, automobile environments are characterized by their a priori unknown topology, i.e., the number, type, and structure of the perceived objects is highly variable. Multi-object detection and tracking methods are a first step to cope with this challenge. Obviously, the existence or non-existence of an object is of paramount importance for safe driving. Such decisions are highly influenced by the association step that assigns sensor measurements to object tracks. Methods that involve multiple sequences of binary assignments are compared with soft-assignment strategies. Finally, fusion based on finite set statistics that (theoretically) avoid an explicit association are discussed.     

模糊合作博弈及其广义核心解的应用研究

为了解决模糊合作博弈传统核心解在资源分配问题中的应用局限,提出了对模糊合作博弈(N,v)中总收益值v(e~N)进行保留,不将全部总收益值分配给所有参与者,进而实现资源再分配或再发展的方案,进一步适应模糊合作博弈核心解的应用需求.首先定义了广义转归、广义核心,广义稳定集等解的概念,然后指出了其含义,在此基础上描述了模糊合作博弈模型.最后以定理证明了各广义核心解之间的关系,说明通过相应系数的调整即可提供合理的分配方案,表明了推广后的模糊合作博弈核心解具有更高的理论及应用价值.     

一种基于系统总误码率的协同伙伴选择算法

提出了一种基于系统总误码率的协同伙伴选择算法。当系统总发送功率一定时,通过系统误码率公式,采用带CRC校验的DF协同通信的协同增益,来降低系统总的误码率。仿真表明,此算法有效地降低了系统总误码率,并且系统SNR越大,协同通信对系统数据传输的帮助越明显。     

Deployment algorithms for a power‐constrained mobile sensor network

This paper presents distributed coverage algorithms for mobile sensor networks in which agents have limited power to move. Rather than making use of a constrained optimization technique, our approach accounts for power constraints by assigning non‐homogeneously time‐varying regions to each robot. This leads to novel partitions of the environment into limited‐range, generalized Voronoi regions. The motion control algorithms are then designed to ascend the gradient of several types of locational optimization functions. In particular, the objective functions reflect the global energy available to the group and different coverage criteria. As we discuss in the paper, this has an effect on limiting each agent's velocity to save energy and balance its expenditure across the network. Copyright © 2009 John Wiley & Sons, Ltd.     

认知无线电系统协作频谱感知机制优化

为使干扰受限情况下的频谱感知效率达到最大,提出一种认知无线电系统协作频谱感知机制的优化方案。定义系统模型,运用协作频谱感知对系统目标进行联合优化,包括感知时间、传输时间、参与协作的感知用户数在内的感知参数优化。仿真结果证明,采用该优化方案,能在满足干扰受限的条件下最大化频谱感知效率。     

多星系统相对轨道的自适应协同控制

基于一致性理论,在无向拓扑结构上对多星系统相对轨道的协同控制问题进行了研究.本文考虑近地卫星相对轨道的非线性方程,首先设计控制律使得多星系统形成目标队形,并给出了速度阻尼和通信拓扑(相对速度间的拓扑关系)连通性之间的关系;其次,针对卫星质量具有不确定性的情形,设计了新的辅助变量,提出了自适应的协同控制律,这里要求传感(相对位置间的拓扑关系)和通信具有相同的拓扑结构.最后对4颗卫星的编队飞行进行了仿真分析,仿真结果表明本文设计的协同控制律是有效可行的.     

Performance analysis and partner selection for cooperative diversity based on MQAM modulation

An adaptive decode-and-forward (DF) cooperative diversity system based on quadrature modulation is proposed, in which each user is allowed to transmit its own and the partner’s data simultaneously via the in-phase and quadrature components of M -ary quadrature amplitude modulation (MQAM) constellation. Cooperative transmission in this way can avoid the bandwidth expansion in traditional cooperative systems. The closed form expression of the average bit error rate (BER) performance is derived in terms of the...     

Robust cooperative output tracking of networked high-order power integrators systems

This paper focuses on a robust cooperative output tracking problem of networked power integrator systems. The dynamics of each system is considered as a nonlinear high-order power integrator whose linearised model is uncontrollable around its origin. It is proven via Lyapunov Theory that under some mild assumptions and graph structural properties, all agents’ outputs in the network can be synchronised to a desired trajectory with a bounded error in the presence of external disturbances as well as model uncertainties. Moreover, the tracking performance can be tuned by appropriately choosing parameters within the controller. The proposed controller for each agent is in the essence constructed via backstepping technique consisting of three components: the state feedback of its own, the outputs of its neighbours and the information of the desired trajectory if connected, and thus in a distributed manner.