服务机器人手臂轨迹规划的研究

利用D-H法建立坐标系、Matlab软件求解正逆方程和插值法处理关节变量来研究服务机器人手臂5个关节空间的轨迹规划问题,实验表明,这种轨迹规划方法是准确和可行的。通过对该方法分析,指出其实现轨迹规划的一般步骤和优缺点,最后展望该轨迹规划法的研究发展方向。     

机械臂控制实验系统研究

针对机械臂在教学实验方面的应用相对欠缺这个问题,介绍了一种实验用多自由度机械臂计算机控制系统。系统由上下位机两级组成,下位机实现关节电机伺服控制、机械臂运行参数自动检测及与上位机的通信。上位机通过视频图像识别技术来规划运动路径,下传命令至下位机,实现自动循迹、工作状态实时显示、指定颜色或形状物体自动抓取等功能。实验结果表明,该系统达到了预期功能。     

智能制造机器人多手臂自适应协同控制方法研究

为妥善解决智能制造机器人系统工作效率低、协作能力差的问题,提出基于一主多从的多手臂自适应协同控制方法。通过分析多臂机器人系统结构明确运动关节、驱动关节及姿态调节装置间的关系,并在惯性坐标系中获取机器人系统线动量和角动量,从而构建雅可比矩阵多手臂运动学方程式。基于此,引入分布式理念简化机器人系统通信链路的冗余性,通过一主多从技术构建多手臂自适应协同控制器,实现其在工业制造中的灵活运用。实验表明:在不同工业制造流程中,应用本文方法后,多臂机器人能够精准完成多条手臂协同抓取工作,证明该方法可以为智能制造的进一步发展提供理论指导。     

Fuzzy force control of constrained robot manipulators based on impedance model in an unknown environment

To precisely implement the force control of robot manipulators in an unknown environment, a control strategy based on fuzzy prediction of the reference trajectory in the impedance model is developed. The force tracking experiments are executed in an open-architecture control system with different tracking velocities, different desired forces, different contact stiffnesses and different surface figurations. The corresponding force control results are compared and analyzed. The influences of unknown parameters of the environment on the contact force are analyzed based on experimental data, and the tunings of predictive scale factors are illustrated. The experimental results show that the desired trajectory in the impedance model is predicted exactly and rapidly in the cases that the contact surface is unknown, the contact stiffness changes, and the fuzzy force control algorithm has high adaptability to the unknown environment. Translated from Journal of Northeastern University (Natural Science), 2005, 26(8): 766–769 [译自: 东北大学学报 (自然科学版)]     

基于模块化设计方法的服务机器人结构设计

为了降低服务机器人的开发周期与成本,基于模块化设计方法,对服务机器人的机械结构进行了模块化划分,并对传动结构布局、传动实现、身体稳固性、模块化结构设计等内容进行了详细阐述。样机组装及实验结果表明,基于模块化设计方法的服务机器人产品开发周期短,其性能达到了设计要求。     

基于三维力反馈的仿壁虎机器人单腿运动控制

分析了仿壁虎机器人机构,建立机器人单腿的运动学模型,并通过代数法求逆解.静态标定三维力传感器并计算分析了传感器解耦矩阵,设计了力信号放大和滤波电路.建立足端黏附材料的弹簧模型,采用增量式关节运动方式,设计了足端三维力反馈控制算法.在Quanser的半实物仿真平台上验证了三维力反馈控制算法.实验表明仿壁虎机器人对足端三维力控制性能良好,三维力反馈控制算法可行,为具有力感知的仿壁虎机器人实现爬壁运动奠定了实验基础.     

Fuzzy theory based control method for an in-pipe robot to move in variable resistance environment

Most of the existing screw drive in-pipe robots cannot actively adjust the maximum traction capacity, which limits the adaptability to the wide range of variable environment resistance, especially in curved pipes. In order to solve this problem, a screw drive in-pipe robot based on adaptive linkage mechanism is proposed. The differential property of the adaptive linkage mechanism allows the robot to move without motion interference in the straight and varied curved pipes by adjusting inclining angles of rollers self-adaptively. The maximum traction capacity of the robot can be changed by actively adjusting the inclining angles of rollers. In order to improve the adaptability to the variable resistance, a torque control method based on the fuzzy controller is proposed. For the variable environment resistance, the proposed control method can not only ensure enough traction force, but also limit the output torque in a feasible region. In the simulations, the robot with the proposed control method is compared to the robot with fixed inclining angles of rollers. The results show that the combination of the torque control method and the proposed robot achieves the better adaptability to the variable resistance in the straight and curved pipes.     

基于阻抗控制的骨外固定机器人矫形力自适应跟踪

针对传统骨外固定器矫形力无法准确控制、安全性差的问题,本文基于 RCM 构型,搭建一种膝关节骨外固定机器人,提出一种间接自适应阻抗的矫形力跟踪方法。 由于存在机械摩擦以及外部不确定性,针对阻抗控制鲁棒性差的问题,采用力误差信号作为目标阻抗的驱动力,建立新的阻抗模型适应矫形环境的变化,根据矫形力误差的变化,设计自适应律对阻抗参数实时调节,在线补偿动态环境的不确定性,使系统的力跟踪误差为零。 并对所提的控制算法进行了胫骨矫形力控制的对比仿真和样机实验。 结果表明:阻抗控制仿真结果各性能指标的加权平均值分别为 2. 12、8. 58 和 13. 2,且力跟踪实验的最大误差为 20 N;相比于阻抗控制,自适应阻抗控制仿真性能指标的加权平均值仅为 0. 36、0. 18 和 0. 61,力跟踪波动误差控制在±3 N 以内,具有更好的鲁棒性和自适应能力。     

基于阻抗控制的机器人力控制算法性能分析

Hogan提出的阻抗控制算法由于必须要求机器人准确的动力学方程,在实际工程背景中很难应用.本文针对其弊端,研究了自适应阻抗控制算法.以平面机械手为控制对象,使用以上两种控制方法对其加以控制,从而详细分析比较了两种算法的性能优劣.最后,针对阻抗控制算法在实际运用中阻抗参数的调整原则一直是比较困难的问题,本文通过仿真实验总结了调参规律.     

A compliance control strategy for robot manipulators under unknown environment

In this paper, a compliance control strategy for robot manipulators that employs a self-adjusting stiffness function is proposed. Based on the contact force, each entry of the diagonal stiffness matrix corresponding to a task coordinate in the operational space is adaptively adjusted during contact along the corresponding axis. The proposed method can be used for both the unconstrained and constrained motions without any switching mechanism which often causes undesirable instability and/or vibrational motion of the end-effector. The experimental results involving a two-link direct drive manipulator interacting with an unknown environment demonstrates the effectiveness of the proposed method.     

基于力估计与切换控制的六足机器人三边遥操作

传统三边遥操作系统的力传感器对主从端交互力进行测量时局限性较大,且在共享权重切换时易导致系统不稳定,本 文设计基于力估计与权重切换控制的六足机器人三边遥操作控制架构。 针对系统各端口交互力信息缺失的问题,设计一种非 线性交互力估计器,实现对各端口间交互力的实时估计。 聚焦双操作者控制权重动态调整过整中的柔顺切换问题,本文基于共 享控制策略,设计权重因子自适应切换算法。 为保证所提出系统的稳定性及透明度,融合力估计器及权重切换算法,设计遥操 作系统的控制器。 通过力反馈设备分别和 Vortex 与 ElSpider 六足机器人搭建半物理仿真平台与实物实验平台,对本文提出控 制方法进行验证。 相对于传统三边遥操作,实验表明在平坦地形下速度跟踪性提高了 45. 12% ,力跟踪提高了 64. 71% ;在崎岖 地形下速度跟踪提高了 39. 02% ,力跟踪提高了 29. 41% 。     

固高工业机器人力/位混合控制

针对固高工业机器人末端主动柔顺控制实现问题,改进并设计了力/位混合控制系统.采用PC+PCI总线采集控制卡的结构,给出了相应的硬件及软件实现方法.实验表明该系统具有良好的稳定性和动态性能.     

基于随机森林回归的手臂末端力的软测量方法

针对手臂康复训练后仍缺乏准确力觉的康复病人提出了一种手臂末端力的软测量方法。采用肌电信号(EMG)传感器与手臂姿态传感器获取的数据综合描述手臂的综合状态信息,并作为随机森林回归的输入,将手臂末端力作为随机森林回归的输出。依据康复训练的基本动作单元,针对性的设计了"推拉"和"提放"两组试验,在离线状态下,利用力传感器测量得到的实际末端力与手臂的综合状态信息作为样本集,并通过大量样本数据训练随机森林回归算子得到稳定可靠的回归算子,最后通过在线预测手臂末端力与真实末端力输出的比较,验证了该方法的有效性。     

基于神经内分泌的并联机器人智能控制系统

为研究一种高速度、高精度的二自由度冗余驱动并联机器人自适应控制系统,通过建立运动学模型,基于神经内分泌甲状腺激素调节原理,设计了一种带长环、超短环结构的神经内分泌智能控制器,对机器人系统进行控制,并给出了其控制算法。仿真分析结果表明,运动学模型简单有效,使机器人运动过程中各个关节运动稳定、连续且平滑;相对于传统PID控制算法,神经内分泌智能控制算法具有较好的快速响应性、稳定性、鲁棒性、自适应性和抗干扰能力。该方法为机器人的复杂控制提出了一种新思路。     

Error Modeling and Sensitivity Analysis of a Parallel Robot with SCARA（Selective Compliance Assembly Robot Arm） Motions

Parallel robots with SCARA（selective compliance assembly robot arm） motions are utilized widely in the field of high speed pick-and-place manipulation. Error modeling for these robots generally simplifies the parallelogram structures included by the robots as a link. As the established error model fails to reflect the error feature of the parallelogram structures, the effect of accuracy design and kinematic calibration based on the error model come to be undermined. An error modeling methodology is proposed to establish an error model of parallel robots with parallelogram structures. The error model can embody the geometric errors of all joints, including the joints of parallelogram structures. Thus it can contain more exhaustively the factors that reduce the accuracy of the robot. Based on the error model and some sensitivity indices defined in the sense of statistics, sensitivity analysis is carried out. Accordingly, some atlases are depicted to express each geometric error’s influence on the moving platform’s pose errors. From these atlases, the geometric errors that have greater impact on the accuracy of the moving platform are identified, and some sensitive areas where the pose errors of the moving platform are extremely sensitive to the geometric errors are also figured out. By taking into account the error factors which are generally neglected in all existing modeling methods, the proposed modeling method can thoroughly disclose the process of error transmission and enhance the efficacy of accuracy design and calibration.     

基于规则库的除冰机器人专家控制方法的研究

本文设计了一种基于规则库的高压线路除冰机器人的专家系统,探讨了其基本结构组成,重点阐述了知识库和推理机的实现方法;通过试验验证了本专家系统的可行性及实用性。     

Direct kinematics of a double parallel robot arm for real time velocity control

The determination of the direct kinematics of a parallel mechanism is a difficult problem but must be solved for practical application. This paper presents the efficient formulation of the direct kinematics and the Jacobian of a double parallel robot arm for velocity control. The robot arm consists of two parallel mechanisms, and a central axis that generates positional and orientational motions independently. Given a set of lengths for the linear actuators, the direct kinematics computes the position and orientation of the end-effector, and the Jacobian transforms the velocities of the end-effector to those of the linear actuators. The developed formulation is implemented in a real-time control setting and its efficiency is demonstrated. Department of Control and Instrumentation Engr.     

Multi-channel control system design for a robot manipulator based on the time-scale method

The problem of controller design for nonlinear multi-channel dynamical plants is discussed. Trajectory motion tracking control for a multilink manipulator is treated as an example of the proposed design methodology. A distinctive feature of the discussed approach to calculate controller parameters is that two-time-scale motions are artificially forced in a closed-loop system where stability of the fast mode is provided by selection of the controller parameters while the induced slow mode correspond to the reference model of desired nonlinear plant behavior. Simulation results for a two-link manipulator robot manipulator tracking control system are presented..     

GPI based velocity/force observer design for robot manipulators

In many applications involving a robot in contact with a surface it is important to control the interaction between the manipulator and its environment, usually by employing force sensors. However, sometimes it is desirable to remove them due to a variety of reasons, e.g. high costs, noisy measurements and a narrow bandwidth. To overcome these drawbacks, in this work it is proposed as a velocity/force observer based on the Generalized Proportional Integral (GPI) technique. Joint velocities and contact forces are estimated with only position measurements and then used in a force/position control scheme. Ultimate boundedness of the observation errors is formally proven and an arbitrarily small ultimate bound is then achieved. Simulation results are used to validate the proposed approach.     

灰色预测在机器人力顺应控制中的应用

大部分机器人控制系统都存在时延性,而过长的时延势必对机器人力顺应控制产生不利的影响,利用灰色系统预测模型对机器人末端受到的力进行预测,提前将其输入到阻抗控制器中,驱动机器人提前响应,降低控制回路纯时延对系统实时性的影响。机器人试验平台是FANUCLRMate200ic六自由度工业机器人,采用在线预更新JOB的方法实现机器人的连续运动控制,造成控制系统存在较大的时延,所以需要对其受力进行多步预测才能达到预期的效果。试验表明,灰色预测模型将系统纯时延造成的位置误差降低到不加预测时的43.11%。