矿井搜救探测机器人驱动系统最小能耗建模与影响因素分析

研究了矿井搜救探测机器人最小能耗影响因素。针对直流伺服电机和减速齿轮驱动下的移动机器人驱动系统,利用Hamiltonian函数与最小值原理求解出驱动系统的最优速度函数和最优控制电流函数,建立了非线性摩擦条件下的最小能耗模型。通过MATLAB仿真,分析了减速器效率[η]、负载、库仑摩擦力和粘性摩擦系数等因素对最小能耗的影响,确定了各参数对驱动系统最小能耗的影响规律。为矿井搜救探测机器人驱动系统消耗能量最小进行参数配置提供依据,对实现机器人节能降耗具有现实的意义。     

Wave CPG model for autonomous decentralized multi-legged robot: Gait generation and walking speed control

In this paper, we propose a method to control gait generation and walking speed control for an autonomous decentralized multi-legged robot by using a wave Central Pattern Generator (CPG) model. The wave CPG model is a mathematical model of nonlinear oscillators and generates rhythmic movements of the legs. The gait generation and the walking speed control are achieved by controlling the virtual energy of the oscillators (Hamiltonian). A real robot experiment showed the relationship to the Hamiltonian, the actual energy consumption and the walking speed, and the effectiveness of the proposed method was verified.     

A Neuro-interface with fuzzy compensator for controlling nonholonomic mobile robots

This paper describes a control method for mobile robots represented by a nonlinear dynamical system, which is subjected to an output deviation caused by drastically changed disturbances. We here propose some controllers in the framework of neuro-interface. It is assumed that a neural network (NN)-based feedforward controller is construcetd by following the concept of virtual master-slave robot, in which a virtual master robot as a feedforward controller is used to control the slave (i.e., actual) robot. The whole system of the present neuro-interface consists of an NN-based feedforward controller, a feedback PD controller and an adaptive fuzzy feedback compensator. The NN-based feedforward controller is trained offline by using a gradient method, the gains of the PD controller are to be chosen constant, and the adaptive fuzzy compensator is constructed with a simplified fuzzy reasoning. Some simulations are presented to confirm the validity of the present approach, where a nonholonomic mobile robot with two independent driving wheels is assmued to have a disturbance due to the change of mass for the robot.     

A family of virtual contraction based controllers for tracking of flexible‐joints port‐Hamiltonian robots: Theory and experiments

In this work, we present a constructive method to design a family of virtual contraction based controllers that solve the standard trajectory tracking problem of flexible‐joint robots in the port‐Hamiltonian framework. The proposed design method, called virtual contraction based control, combines the concepts of virtual control systems and contraction analysis. It is shown that under potential energy matching conditions, the closed‐loop virtual system is contractive and exponential convergence to a predefined trajectory is guaranteed. Moreover, the closed‐loop virtual system exhibits properties such as structure preservation, differential passivity, and the existence of (incrementally) passive maps. The method is later applied to a planar RR robot, and two nonlinear tracking control schemes in the developed controllers family are designed using different contraction analysis approaches. Experiments confirm the theoretical results for each controller.     

机器人虚拟仿真及远程控制系统的研究及实现

机器人虚拟仿真及其与远程控制相结合,表现出独特的优势,应用前景广阔。应用OpenGL和WinSock技术,设计并实现了机器人虚拟仿真及其远程控制系统。建立基于C#与OpenGL的虚拟仿真平台,实现了机器人虚拟现实的运动仿真;建立基于WinSock的远程控制系统,提出基于反射原理的解释器模式,实现了机器人远程面板或程序控制;提出基于速度向量场的改进无碰轨迹规划算法,有效对静态与动态障碍物安全避障。系统测试结果表明该机器人虚拟仿真及远程控制系统有较好的准确性和稳定性。     

Adaptive robust simultaneous stabilization of multiple n-degree-of-freedom robot systems

In this paper, the adaptive robust simultaneous stabilization problem of uncertain multiple n-degree-of-freedom (n-DOF) robot systems is studied using the Hamiltonian function method, and the corresponding adaptive L2 controller is designed. First, we investigate the adaptive simultaneous stabilization problem of uncertain multiple n-DOF robot systems without external disturbance. Namely, the single uncertain n-DOF robot system is transformed into an equivalent Hamiltonian form using the unified partial derivative operator (UP-DO) and potential energy shaping method, and then a high dimensional Hamiltonian system for multiple uncertain robot systems is obtained by applying augmented dimension technology, and a single output feedback controller is designed to ensure the simultaneous stabilization for the higher dimensional Hamiltonian system. On this basis, we further study the adaptive robust simultaneous stabilization control problem for the uncertain multiple n-DOF robot systems with external disturbances, and design an adaptive robust simultaneous stabilization controller. Finally, the simulation results show that the adaptive robust simultaneous stabilization controller designed in this paper is very effective in stabilizing multi-robot systems at the same time.     

虚拟现实技术下分拣机器人嵌入式遥控系统设计

为了解决当前遥控系统控制分拣机器人执行既定任务时存在目标轨迹跟踪效果不佳、跟踪误差较大,任务执行成功率较低、失误率较高以及系统响应延迟时间较长等缺点,提出并设计了基于虚拟现实技术的分拣机器人嵌入式遥控系统,研究通过分析虚拟现实系统组成结构基础上,将虚拟现实技术与分拣机器人技术有机结合,依据模块化、标准化、开放性和可用性原则,利用虚拟现实技术设计了具有临场感的操作指令输入输子系统和分拣机器人具有真实感的虚拟场景仿真子系统的嵌入式遥控系统;并给出了嵌入式遥控系统的基本功能单元和具体操作流程;依据该流程采用QNX Neutrino系统作为分拣机器人本体控制器,同时采用工业现场总线EtherCAT作为系统网络通信支撑,设计了嵌入式遥控系统软件控制程序,完成了基于虚拟现实技术的分拣机器人嵌入式遥控系统设计。模拟实验结果验证了设计系统的有效性,获得了较好的目标跟踪效果,减小了跟踪误差,提高了分拣机器人任务执行成功率,同时提高了系统效率。     

Multiagent-Based Multi-team Formation Control for Mobile Robots

In the field of formation control, researchers generally control multiple robots in only one team, and little research focuses on multi-team formation control. In this paper, we propose an architecture, called Virtual Operator MultiAgent System (VOMAS), to perform formation control for multiple teams of mobile robots with the capabilities and advantages of scalability and autonomy. VOMAS is a hybrid architecture with two main agents. The virtual operator agent handles high level missions and team control, and the robot agent deals with low level formation control. The virtual operator uses four basic services including join, remove, split, and merge requests to perform multi-team control. A new robot can be easily added to a team by cloning a new virtual operator to control it. The robot agent uses a simple formation representation method to show formation to a large number of robots, and it uses the concept of potential field and behavior-based control to perform kinematic control to keep formation both in holonomic and nonholonomic mobile robots. In addition, we also test the stability, robustness, and uncertainty in the simulation. This research was supported by the National Science Council under grant NSC 91-2213-E-194-003.     

Transition to an optimal periodic gait by simultaneous input and parameter optimization method of Hamiltonian systems

This paper is concerned with a gait transition to an optimal periodic gait by a simultaneous input and parameter optimization technique of Hamiltonian systems. First, a continuous-time dynamics of a passive walking/running robot between the touchdown and lift-off is considered as a Hamiltonian system. Then, the control input and some robot parameters, such as the mass, inertia, link length, and so on, are optimized using learning optimal control of Hamiltonian systems, which has been developed by the authors. This method allows one to simultaneously obtain an optimal feedforward input and optimal parameters, which (at least locally) minimize a given cost function. The main advantage is that the precise model of the dynamics of the plant system is not required using a symmetric property of Hamiltonian systems, called variational symmetry. We formulate an optimal gait generation scheme via the learning optimal control, where the robot keeps walking and the gait is optimized with respect to the control input and some adjustable robot parameters simultaneously. As a result, the gait transition to an optimal periodic one is achieved.     

Development of a cooperative trajectory control system for two robots based on sensory data

This paper describes a basic design for a cooperative control system for multiple robot arms. In the system, two robot arms and a vision subsystem have their own node controllers connected by a computer network. The cooperative control software developed is embedded in each node controller. The node software is written by an object-oriented programming technique. The system model is constructed as a basis for representing and interpreting a cooperative task. To provide uniform methodology for obtaining external information on modelled objects in the real world, a virtual information source-a sensorlink-is designed. Real information sources distributed among the node locations are transparently accessed by a sensorlink. The task requirements imposed on the system are reduced to internal restriction laws. When a motion trajectory of the task constrains the two arms in relation to each other, the laws leave degrees of freedom available by which the arms can find an alternative solution to the task. The example task executed is to push a button on a box held by one arm with the other arm's hand tip. The two arms move their hands in accordance with the laws using visual information provided through a sensorlink. Then difficulty in keeping the law at a node-for example, a joint stop caused by the restricted workspace-can be avoided by cooperative use of unconstrained degrees of freedom.     

基于虚拟现实的机器人智能控制系统

本文基于虚拟现实技术特点,构建了虚拟现实环境下的机器人智能控制系统,将Eon Studio与VC++可视化结合构建人机交互平台,将系统分为人机交互系统和遥控机器人系统部分,采用3DS MAX建立虚拟场景和机器人,基于TCP/IP协议的无线局域网技术进行数据交互,并利用EonX空间进行Eon和VC++6.0的通信.通过实...     

Modelling of Bound Estimation Laws and Robust Controllers for Robustness to Parametric Uncertainty for Control of Robot Manipulators

In this paper, first, a new approach is proposed for derivation of bound estimation laws for robust control of robot manipulators. In this approach, functions depending on robot kinematics and control parameters and integration techniques can be used for derivation of the bound estimation laws based on the Lyapunov theory, thus, stability of the uncertain system is guaranteed. Five new bound estimation laws are proposed, and in this derivations, five novel functions depending on robot kinematics and control parameters and proper integration techniques, such as substitution method, integration by part and integration by partial fractions are used. Then, four new robust control inputs are proposed based on each derived bound estimation law. Lyapunov theory based on Corless and Leitmann (IEEE Trans Automat Contr 26:1139–1144, 1981) approach is used for designing the robust control input achieving uniform boundedness error convergence. This study also allows derivation of other bound estimation laws for robust controllers provided that appropriate novel functions and proper integration techniques are chosen.     

Reactive Path Planning in a Dynamic Environment

This paper deals with the problem of path planning in a dynamic environment, where the workspace is cluttered with unpredictably moving objects. The concept of the virtual plane is introduced and used to create reactive kinematic-based navigation laws. A virtual plane is an invertible transformation equivalent to the workspace, which is constructed by using a local observer. This results in important simplifications of the collision detection process. Based on the virtual plane, it is possible to determine the intervals of the linear velocity and the paths that lead to collisions with moving obstacles and then derive a dynamic window for the velocity and the orientation to navigate the robot safely. The speed of the robot and the orientation angle are controlled independently using simple collision cones and collision windows constructed from the virtual plane. The robot's path is controlled using kinematic-based navigation laws that depend on navigation parameters. These parameters are tuned in real time to adjust the path of the robot. Simulation is used to illustrate collision detection and path planning.      

Robust formation tracking control of mobile robots via one-to-one time-varying communication

We solve the formation tracking control problem for mobile robots via linear control, under the assumption that each agent communicates only with one ‘leader’ robot and with one follower, hence forming a spanning-tree topology. We assume that the communication may be interrupted on intervals of time. As in the classical tracking control problem for non-holonomic systems, the swarm is driven by a fictitious robot which moves about freely and which is a leader to one robot only. Our control approach is decentralised and the control laws are linear with time-varying gains; in particular, this accounts for the case when position measurements may be lost over intervals of time. For both velocity-controlled and force-controlled systems, we establish uniform global exponential stability, hence consensus formation tracking, for the error system under a condition of persistency of excitation on the reference angular velocity of the virtual leader and on the control gains.     

Polynomial family of PD-type controllers for robot manipulators

This paper addresses the problem of position control for robot manipulators. A new polynomial family of PD-type controllers with gravity compensation for the global position of robots manipulators is presented. The previous results on the linear PD controller are extended to the proposed polynomial family. The classical PD controller can be found among this large class of controllers when its proportional gain is a diagonal matrix. The main contribution of this paper is to prove that the closed-loop system composed by full nonlinear robot dynamics and the proposed family of controllers is globally asymptotically stable in agreement with Lyapunov's direct method and LaSalle's invariance principle. Besides the theoretical results, a real-time experimental comparison is also presented to illustrate the performance of the proposed family with other well-known control algorithms such as PD and PID schemes on a three degrees of freedom direct-drive arm.     

Preface

This paper discusses the problems in teleoperation systems for a mobile robot and the utilization of a virtual world in such systems. In order to achieve smooth operation of the mobile robot through a communication link, we should consider time delays in data transfer. To compensate for the incomplete data sets, the virtual images can be generated by computer graphics when the information on the working environment can be acquired beforehand. In this paper, we construct a teleoperation system with a virtual world. The performance of the system is examined through experiments with actual mobile robots which show that the virtual robot can be operated by an operator in almost the same manner as the teleoperated real robot. In an experimental environment with a second moving robot, we can keep the status of the second robot under perfect control and operate the first robot with no interference.     

一种非线性PD控制器设计

为了提高PD控制器的性能,提出了一种非线性设计方法。利用电容极间电场和PD控制器的控制作用之间存在的一些相似性,构造了一种非线性函数,并以此形成一种非线性PD控制器,这种控制器能为系统的运行状态提供灵活的增益策略;利用系统的运行状态信息,在相平面中实时旋转该电容结构,可以减少这种非线性PD控制器的设计参数。通过对一个机械手系统进行仿真,结果表明,这种控制方式能够获得较好的系统动态响应速度和参数鲁棒性能。     

基于能量的蛇形机器人蜿蜒运动控制方法的仿真与实验研究

能量作为最基本的物理量之一, 联系着蛇形机器人蜿蜒运动的各个方面. 能量耗散描述了环境交互作用, 能量转换对应着运动的动力学过程, 能量平衡反映了蜿蜒运动的协调性. 提出一种基于能量的蛇形机器人蜿蜒运动控制方法-被动蜿蜒. 通过输出关节力矩控制机器人蜿蜒运动, 由机器人的能量状态调整力矩的大小. 仿真结果显示了被动蜿蜒控制下机器人的构形、角度、力矩、能量状态和转弯特性, 并对控制力矩进行了递归分析. 基于Optotrak运动测量系统构建了被动蜿蜒控制的模拟/物理混合实验系统. 进行了移动实验和拖动实验, 前者改变环境的摩擦特性,后者改变机器人的负载. 仿真和实验验证了蛇形机器人被动蜿蜒控制的有效性和适应性.     

Energy-based balance control approach to the ball and beam system

This article investigates the set-point balance control problem of the ball and beam system acting on the ball which is an underactuated system. The control law is designed, based on the total mechanical energy and the passivity properties of the system. According to the desired set-point, the zero equilibrium point and non-zero equilibrium points are studied respectively. For the zero case, it is proved that a single PD feedback controller is sufficient to bring the state to zero from any initial condition, on condition that the control parameters satisfy an inequality. For the non-zero case, the control problem is much more complicated. Unlike the previous energy-based control laws, a new form of Lyapunov function candidate is constructed. A complete analysis of the convergence of the energy and the dynamics is given, and the characteristics of the closed-loop system with the proposed feedback control law are illustrated. Moreover, it is proved that with the parameter choice rules proposed in this article, the ball and beam system will eventually converge exactly to the desired non-zero equilibrium point. Furthermore, since the length of the beam is not unlimited, the trajectory of the ball should be restricted within a limited range. The balance control laws are modified to avoid the ball running beyond the joint range limitation for the zero case and the non-zero case respectively. Simulation results show that the control laws proposed in this article are effective for the set-point balance control problem of the ball and beam system.     

PMSM驱动机器人的FSMC与EPCH协同控制

单独一种控制方法难以使机器人末端快速、准确地跟踪位置变化,针对这一问题,提出了模糊滑模(FSMC)信号控制与误差端口受控哈密顿(EPCH)能量控制的协同控制策略.FSMC解决了系统动态时的快速性问题,EPCH控制解决了系统稳态时的准确性问题.设计了基于误差的协同函数,利用协同函数来实现对机器人关节系统的协同控制,使机器...