多智能体机器人系统分散式通信决策研究

为了减少多智能体机器人系统协调所需通信的数量,提出了一种新的方法.利用有向无环图表示团队的可能联合信度,并基于此以分散式的方式制定通信决策,仅当智能体自身的观察信息显示共享信息将导致期望回报升高时才选择通信.通过维持以及推理团队的可能联合信度将集中式单智能体策略应用于分散式多智能体POM-DP问题.通过实验以及一个详细的实例表明,本文方法能够有效地减少通信资源的使用,同时提高分散执行的性能.     

多个地面移动机器人建立构型空间

研究多机器人系统运动规划问题,经典的构型空间(C-space)通常用于静态障碍物并且机器人有环境全局知识的假设下.有局部传感能力的多机器人系统(MRS)不具备全局规划性能.针对上述问题,要求MRS建立C-space功能,采用环境和机器人的模型建立多边形集合,每个机器人都是自主地面移动机器人.机器人的传感范围是有限的,并能互相通讯.一种分散式的算法被提出来解决两个机器人探索环境并建立构型空间障碍的任务,两个机器人定期的交换和合并对方产生的部分构型空间障碍,直到整个构型空间障碍建立.算法类似于同时绘图与定位(CML),采用产生和合并C-space的算法进行仿真,结果表明了算法的有效性.     

基于分散式的多机器人避碰协调控制

针对多机器人在路径规划时躲避其他机器人容易产生抖动问题,该文提出了一种分散式的多机器人之间碰撞协调机制,设计了一种协调碰撞的算法,该方法计算短时间范围内的无碰撞局部运动。基于机器人动力学约束安全和平滑的控制,该方法在基于速度障碍算法的概念上,扩展现实机器人的动力学约束,考虑环境的基于网格的地图表示,通过仿真实验证明了所提出的算法是有效的,可以使运动更加平滑。     

基于健康管理的多机器人覆盖控制

装备了传感器的多机器人系统可以在各种场景中完成覆盖搜索任务,例如污染源监测和控制。而传统基于CVT的覆盖控制算法未曾考虑到环境对机器人健康的影响,以及不同健康机器人对覆盖成本的影响。针对上述问题,提出了一种基于健康优化管理的多机器人覆盖控制算法。首先引入多机器人健康优化管理办法,将机器人的健康退化纳入位置优化问题,最大程度地减少机器人的健康损耗,并尽可能地延长不健康机器人的工作寿命;其次引入基于加权维诺的分布式覆盖控制方法,为多机器人提供最优配置的同时最小化代价函数;目标是当机器人执行任务的能力随时间变化时,执行覆盖任务,提供最优配置。最终通过数值仿真和实验验证了所提算法的有效性。     

多处理机工作池方式负载平衡技术在机器人的应用

文章阐述了利用集中式工作池动态负载平衡和分散式工作池动态负载平衡这两种方法来解决机器人多处理机控制器中各处理器间合理地分配计算问题,以获得最快的可能执行速度,使得控制器中的CPU资源能够充分利用并协同工作,以最大限度地提高机器人性能。     

一种新型的冗余机器人任务空间分散式自适应鲁棒控制方案

本文提出一种任务空间冗余机器人渐近最优分散式自适应鲁棒控制方案。它可以在线同时完成关节状态的轨迹规划与控制任务;并对系统的未知参数具有自适应能力;对参数失配,有界扰动以及系统控制与状态约束具有鲁棒性。     

机器人及机械系统自适应控制的研究

本文给出了作者在机器人控制领域所做的以下工作: 1)针对机器人杆身结构上的特点,首先提出一种利用输入输出积分寻求自适应控制律的新方法;2)将负载质量从机器人动力学方程中分离出来,给出其一般的表现形式。在此基础上,利用作者提出的输入输出积分寻求自适应控制律的方法,得到了针对负载未知时在广义坐标空间和任务坐标空间中的轨迹跟踪、点到点以及模型参考自适应控制,并研究了在有界扰动时的鲁棒自适应控制;3)研究了除负载质量未知外还有其它参数未知时,在广义坐标空间和任务坐标空     

EMR系统机器人运动学和工作空间的分析

本文研究了EMR系统机器人的运动学和工作空间。首先对机器人的工作空间进行了分析,并提出了求解机器人末端灵活性的方法;接着解决了机器人位姿正运动学描述和逆运动学求解的问题;最后针对欠自由度的机器人结构,提出采用一组变量来描述机器人的速度运动学,避免了采用伪逆求逆速度运动学。     

基于三阶超螺旋滑模观测器算法的机器人力矩估计方法

本文研究了六自由度(6-DOF)机器人关节力矩估计问题.为了提高机器人关节力矩估计精度,本文设计了一种三阶超螺旋滑模关节力矩观测器.在对观测器系统进行稳定性分析时,本文设计了一种新的Lyapunov函数证明了观测器闭环系统的稳定性.与已有的机器人力矩观测器结果不同,该力矩观测器仅以机器人关节角度作为观测器输入信号,减少了对机器人系统信息的依赖.最后,以6-DOF工业机器人为对象,开展实验验证.实验结果表明,与传统线性力矩观测器相比,本文提出的滑模力矩观测器估计误差小,验证理论的正确性.     

多机器人从正六边形区域在线撤离算法研究

针对多机器人在线撤离未知多边形区域展开研究,在原有撤离区域模型（三角形、正方形、圆形）的基础上提出多机器人从正六边形区域在线撤离问题。设置出口在正六边形区域的边界上,2k（k≥1）个具有无线通信能力的机器人从相同起点出发,协作搜索出口并撤离。使用机器人全部从出口撤离的时间作为算法的开销,分析算法的效率。根据机器人数量和初始位置分情况讨论,k=1时,机器人的初始位置分别位于正六边形区域的边界和内部;k>1时,机器人初始位置在正六边形区域的边界。针对上述几种情况,分别给出了高效的多机器人协作在线撤离算法,并证明在机器人起点相同的情况下,增加机器人数量对减少算法开销具有正向的意义。     

Robust decentralized actuator fault detection and estimation for large-scale systems using a sliding mode observer

In this paper, robust decentralized actuator fault detection and estimation is considered for a class of non-linear large-scale systems. A sliding mode observer is proposed together with an appropriate coordinate transformation to find the sliding mode dynamics. Then, based on the features of the observer, a decentralized fault estimation strategy is proposed using an equivalent output error injection, and a decentralized reconstruction scheme follows by further exploiting the structure of the uncertainty which is allowed to have non-linear bounds. The estimation and reconstruction signals only depend on the available measured information and thus the proposed strategy can work on-line. The theoretical results which have been obtained are applied to an automated highway system. Simulation shows the feasibility and effectiveness of the proposed scheme.     

分散模型参考自适应控制

本文针对由参数未知、存在有界扰动和非线性关联的子系统组成的大规模互联系统,提出 了一种新的分散模型参考自适应控制法.它适用于孤立子系统传递函数的相对阶次n*i为任 意值的情况.根据李雅普诺夫稳定性理论,文中证明了这种分散自适应控制系统全局稳定的 充分条件.与有关文献所介绍的方法相比,本文的方法可用于n*i>2的场合,因而它更具有 一般性和实用性.     

Fault-tolerant control for a class of non-linear systems with dead-zone

In this paper, a fault-tolerant control scheme is proposed for a class of single-input and single-output non-linear systems with the unknown time-varying system fault and the dead-zone. The non-linear state observer is designed for the non-linear system using differential mean value theorem, and the non-linear fault estimator that estimates the unknown time-varying system fault is developed. On the basis of the designed fault estimator, the observer-based fault-tolerant tracking control is then developed using the backstepping technique for non-linear systems with the dead-zone. The stability of the whole closed-loop system is rigorously proved via Lyapunov analysis and the satisfactory tracking control performance is guaranteed in the presence of the unknown time-varying system fault and the dead-zone. Numerical simulation results are presented to illustrate the effectiveness of the proposed backstepping fault-tolerant control scheme for non-linear systems.     

Decentralized Adaptive Control of Interconnected Non-Linear Systems Using High Gain Observer

This paper investigates a decentralized adaptive control strategy for a class of interconnected unknown non-linear systems. The idea of the strategy is based on the feedback linearizing control and perturbation estimation. A high gain observer is designed in association with each sub-system to estimate the states and a fictitious state which is defined to represent the system perturbation including the combined effect of system non-linearities, unknown system dynamics, disturbances and interactions between sub-systems. Subject to the availability of sub-system states, two local controllers — decentralized non-linear adaptive state-feedback controller (DNASFC) and decentralized non-linear adaptive output-feedback controller (DNAOFC) — are developed using a high gain perturbation observer (HGPO) or a high gain state and perturbation observer (HGSPO) respectively. The stability and error analysis of the high gain observers and the closed-loop control systems are addressed in detail. The two proposed controllers are evaluated on an interconnected non-linear system involving two inverted pendulums on carts without velocity measurements.     

Multivariable disturbance observer-based H2 analytical decoupling control design for multivariable systems

In this paper, an H₂ analytical decoupling control scheme with multivariable disturbance observer for both stable and unstable multi-input/multi-output (MIMO) systems with multiple time delays is proposed. Compared with conventional control strategies, the main merit is that the proposed control scheme can improve the system performances effectively when the MIMO processes with severe model mismatches and strong external disturbances. Besides, the design method has three additional advantages. First, the derived controller and observer are given in analytical forms, the design procedure is simple. Second, the orders of the designed controller and observer are low, they can be implemented easily in practice. Finally, the performance and robustness can be adjusted easily by tuning the parameters in the designed controller and observer. It is useful for practical application. Simulations are provided to illustrate the effectiveness of the proposed control scheme.     

Design of a sliding mode control system for chemical processes

This paper considers the non-linear regulation control of chemical processes. A novel and systematic sliding mode control system design methodology is proposed, which integrates an identified second-order plus dead-time (SOPDT) model, an optimal sliding surface and a delay-ahead predictor. The convergence property of the closed-loop system is guaranteed theoretically by means of satisfying a sliding condition and the control system performance is examined with some typical chemical processes. Besides, with the concept of delay equivalent, the proposed sliding mode control scheme can be utilized directly to the regulation control of a non-minimum phase process. As a special case the proposed scheme is further extended to the control of chemical processes whose dynamics are simply described by a first-order plus dead-time (FOPDT) model. In addition, the decentralized sliding mode control scheme for multivariable processes is also explored in this paper. Extensive simulation results reveal that the proposed sliding mode control system design methodology is applicable and promising for the non-linear regulation of time-delay chemical processes.     

Adaptive fuzzy decentralized control for nonlinear large-scale systems based on high-gain observer

An adaptive fuzzy decentralized backstepping output-feedback control approach is proposed for a class of nonlinear large-scale systems with completely unknown functions,the interconnections mismatched in control inputs,and without the measurements of the states.Fuzzy logic systems are employed to approximate the unknown nonlinear functions,and an adaptive high-gain observer is developed to estimate the unmeasured states.Using the designed high-gain observer,and combining the fuzzy adaptive control theory with backstepping approach,an adaptive fuzzy decentralized backstepping output-feedback control scheme is developed.It is proved that the proposed control approach can guarantee that all the signals of the closed-loop system are semi-globally uniformly ultimately bounded(SUUB),and that the observer errors and the tracking errors converge to a small neighborhood of the origin by appropriate choice of the design parameters.Finally,a simulation example is provided to show the eectiveness of the proposed approach.     

基于扩张状态观测器的分散模型预测控制

针对复杂关联系统中分散控制方法无法有效解决子系统间的耦合和干扰问题, 提出一种基于扩张状态观测器的分散模型预测控制算法. 首先将复杂关联系统分解为多个状态维数较低、控制变量较少的子系统, 并为每个子系统设计本地预测控制器; 然后, 采用扩张状态观测器对子系统的耦合项以及干扰项进行估计, 进而利用估计值对子系统进行前馈补偿, 从而降低复杂关联系统的计算复杂度, 提高系统的稳定性和抗干扰能力; 最后, 利用液位控制系统验证了所提出算法的有效性.

     

Adaptive fuzzy decentralized output feedback control for stochastic nonlinear large‐scale systems using DSC technique

In this paper, an adaptive fuzzy decentralized backstepping output feedback control approach is proposed for a class of uncertain large‐scale stochastic nonlinear systems without the measurements of the states. The fuzzy logic systems are used to approximate the unknown nonlinear functions, and a fuzzy state observer is designed for estimating the unmeasured states. Using the designed fuzzy state observer, and by combining the adaptive backstepping technique with dynamic surface control technique, an adaptive fuzzy decentralized output feedback control approach is developed. It is shown that the proposed control approach can guarantee that all the signals of the resulting closed‐loop system are semi‐globally uniformly ultimately bounded in probability, and the observer errors and the output of the system converge to a small neighborhood of the origin by choosing appropriate design parameters. A simulation example is provided to show the effectiveness of the proposed approaches. Copyright © 2011 John Wiley & Sons, Ltd.