A hybrid control method for telerobotic systems

A hybrid control method for telerobotic systems which considers simultaneously the control and decision-making issues is presented in this paper. Telerobotic system is a typical hybrid system which contains both continuous-time and discrete event dynamics. Specifically, the robot can be considered as a continuous-time system modeled customarily by differential equations or difference equations, and the human operator whose function is to generate commands for robot located in the remote side, however, can be modeled by an automaton. As a result, telerobotic system is a heterogeneous system and the heterogeneity can be characterized by the fact that humans are intelligent while robots arc fast, powerful and accurate. From the point of view of control, a hybrid framework is of key importance for the study of such a system. In this paper, the specific problems to be discussed include developing a framework in which both the robotic system and the human operator can be modeled simultaneously, and introducing how to apply this framework in a real teleoperated manipulator system. The main contribution of this paper is the development of a mathematical model which incorporates human intervention into an autonomous control model

Attractive force guided grasping for a teleoperated manipulator system based on monocular vision

A method is presented here, based on the monocular vision, to provide haptic/force information for the operator which is used to signal to the operator the posture of end effecter relative to the object to be grasped During the process of grasping, the information concerning the relative posture between the end effecter and the object is of key importance, especially when the end effecter is in the vicinity of the object. Although video information plays a major role in monitoring collision between robot and the object and fine-tuning the end effecter towards the object, the operator should make strict observations about the video images to take precautions against collision between robot and the object. As a result, operators might miss or neglect the advance notice of collision. In view of this problem, vision information obtained from a monocular camera is transformed into haptic information to which operators are more sensitive. Operators can give large master commands confidently without having to consider collision, and accordingly become released from the anxiety about the collision. At the same time, the efficiency of the telerobotic system is enhanced greatly

Control of Wheeled Mobile Robots Based on Motion Description Languages

介绍了一种基于运动描述语言的轮式移动机器人控制方法.运动描述语言不仅可以有效地描述机器人系统中离散和连续动力学过程的相互作用,而且可以定量地描述操纵机器人的复杂性.利用该方法对具有非完整约束的轮式移动机器人的位姿镇定问题进行了研究,仿真结果验证了该方法的有效性

Control and Study of Internet-based Teleoperation Robot System on Agent

为了充分发挥智能机器人的自主性和人的主观能动性,实现通过网络遥操作非结构化环境下的智能机器人,提出了一种基于Agent的网络遥操作机器人控制系统结构,分析了控制系统中各部分的功能,给出了系统中各个Agent的实现方法。该控制方法已通过仿人形机器人的遥操作控制实验得到了验证

Network-based Tele-robotic System with Guidance Functionality from Virtual Force

为实现机器人网络遥操作系统中从端机器人和被抓取目标接触前的力觉感知效果,提出了具有虚拟力觉导引功能的机器人网络遥操作系统控制方法.利用单目视觉技术获得末端执行器相对于被抓取目标的位姿信息,并将此信息转换为操作者相对敏感的力反馈信息,引导操作者为远端机器人系统提供合适的控制命令,控制机器人达到期望的位姿.利用手腕相机和人工目标搭建了演示实验系统,并分别进行了机器人位置和姿态遥操作控制实验.实验结果表明,机器人遥操作系统的可操作性和操作效率有了明显提高.</p

MDL-Based Control Method for Tele-robotic Systems

为了降低遥操作系统对网络带宽的需求,实现系统中计算、通信等功能的合理划分,提出了基于运动描述语言(MDL)的机器人网络遥操作系统控制方法.利用机器人运动轨迹正交分解的方法得到了运动基元模型中的开环与闭环控制参数,保证了MDL的描述能力,并针对遥操作抓取任务定义了4类运动基元.以Phantom Omni为主端控制器、Motoman 6自由度机器人为被控对象建立了基于网络的机器人遥操作系统,并针对直接控制方法和基于MDL的控制方法进行了对比实验,实验结果验证了该方法的可行性与有效性

A linguistic control method for posture stabilization of wheeled mobile robot

A linguistic control method based on motion description languages for posture stabilization of wheeled mobile robot is presented in this paper. In robotic systems control actions should be selected and executed by the triggering events. As a result, robotic systems typically posses a hierarchical structure, characterized by continuous variable dynamics at the lowest level and logical decision - making at the highest. Motion description languages, inspired by formal languages and automaton theory, serve as an abstraction between continuous and discrete control. Unlike traditional methods, the linguistic control method can be used to describe completely for interactions between robot and the environments in which it operates, and the complexity for steering a robot can also be measured quantitatively. The posture stabilization problem for wheeled mobile robots is studied and simulation results verify the validity of this method

Symbolic-based motion control method for wheeled mobile robots

A symbolic-based motion control method for wheeled mobile robots is put forward in this paper. Wheeled mobile robots, which are characterized by the nonholonomic constraints, are particularly difficult to control since real environment may be full of obstacles. Traditional methods have to resort to analysis and design at the level of individual sensors and actuators. As a result, the richness of the set of mappings from sensor to actuator signals constitutes a great challenge in determining a suitable control law to steer the wheeled mobile robot. In view of those considerations, a symbolic-based control method is presented, in which control procedures have a natural, linguistic flavor. In this method, different control procedures can be generated from a finite set composed of symbols which correspond to different control actions. It is obvious that this method allows one to design feedback control laws at the level of strings and primitives, rather than at the level of sensors and actuators. Simulation results show that the proposed method is effective for the control of wheeled mobile robots. © 2009 IEEE.</p

Generalized Predictive Control for Space Teleoperation Systems Based on Time Delay Prediction

针对导致遥操作系统性能下降甚至不稳定的时变大时延问题,提出一种基于在线时延预测的广义预测控制(GPC)方法。鉴于空间遥操作系统一般由多自由度主、从端构成,而且环境模型未知,则在主端以一种基于稀疏矩阵的核非线性回归方法设计时延预测器,同时将多自由度从端机械臂的非线性动力学模型线性化,根据预测的时延设计GPC,使系统稳定并且满足位置和速度跟踪性能要求。在从端,通过设计非线性补偿器以补偿从端的非线性部分。仿真取得有效结果

Generalized predictive control for space teleoperation systems with long time-varying delays

Prior researches of generalized predictive control (GPC) in teleoperation systems have mainly considered short transmitted time delays or single degree of freedom (DOF) manipulators of master and slave. This paper presents a GPC strategy for space teleoperation systems in which the master and slave manipulators are both multi-DOF and the communication network brings long time-varying delays. The nonlinear dynamics of the multi-DOF slave manipulator is linearized and described by a linear state-space equation. Meanwhile, a nonlinear compensator is used to compensate the nonlinear parts of the slave. Then, based on the equation, a state-space model based GPC controller is designed on the master side to stabilize the system and make the slave manipulator track the master position and velocity no matter whether the manipulator contacts with the environment or not. Finally, a simulation example is given to illustrate the effectiveness of the proposed method