Robotic automatic assembly system for random operating condition

A vision guided tabletop robotic assembly system is constructed for the random environment automatic assembly purpose. The distributed control structure is designed for this assembly system. A PC is specified as the central control unit for machine vision operation and the harmonization of At89c51 distributed control unit for each axis. The machine vision is introduced to search the locations and measure the size of the assembly parts in the robotic workspace. Then, the central controller commands the robot to pick the part sequentially based on the specified program to complete the automatic assembly process. The model-free fuzzy sliding mode control scheme is embedded in each joint micro controller for simplifying the model based control problem. The central control unit PC communicates with each joint controller by network communication. This assembly system is implemented on a 3 DOF SCARA robot. The experimental results show that the robotic motion control performance is good enough for assembling work; the vision pattern classification and assembly motion paths planning and monitoring are exactly executed by the central control unit. The goal of this robotic random assembly operation is achieved with the appropriate integration of robotic motion control, machine vision, sensor and assembly force detecting techniques.     

基于足底力反馈的踝关节主被动康复策略

踝关节机能损伤人群数量增长与康复医师紧缺是现阶段面临的一个重要社会问题,为此,基于一款2-SPU/RR踝关节康复机器人提出一种主被动结合的辅助康复策略。首先建立虚拟样机模型和对应的结构简图,进行运动学分析,求解了机器人的工作空间,结果表明该机器人能够满足踝关节跖屈-背屈和内翻-外翻复合运动需求。然后针对目前康复机器人主要研究内容为被动康复问题,未能根据患者脚踝实际损伤情况进行康复,提出一种踝关节机器人主被动康复结合的方法。先预设康复运动轨迹,基于足底压力数据和力感知算法获得患者的运动意图,通过软硬件控制系统实现机器人主动跟随,同时将运动轨迹进行记录和数据化。最后对描迹轨迹进行优化,根据优化轨迹使用5段S型加减速控制方式进行定制化被动康复。主被动康复系统实现了机器人跟随控制与患者主动行为感知的结合,有助医师对踝关节机能损伤患者的诊断与治疗。     

图像反馈机器人视觉伺服系统理论与实验研究

对机器人视觉伺服系统的研究是机器人领域中的重要内容之一,其研究成果可应用在机器人自动避障、轨线跟踪和运动目标跟踪等问题中。本文分析了基于图像雅克比矩阵的机器人视觉伺服方法的基本原理,采用了基于图像的视觉伺服方法,直接利用图像特征来控制机器人运动,构建了自由度GRB-400工业机器人图像反馈视觉伺服系统。采用该系统进行了机器人跟踪两维平面运动目标的实验,结果验证了该方法的有效性。     

人体卧式下肢屈伸运动的动力学建模与仿真

为了帮助脑卒中后偏瘫、单侧肢体运动障碍的患者进行下肢康复训练,基于人机合作技术提出了一种下肢康复训练机器人。该机器人根据患者的运动意愿,通过与人合作完成下肢的康复训练。引入广义速率的概念,基于凯恩方法对人体卧式下肢屈伸运动进行了动力学建模与仿真,求解了下肢屈伸运动的约束方程和凯恩方程,得到了下肢运动曲线和驱动力矩曲线。该研究为下肢康复训练器械的设计与研制提供了参考和理论依据。     

Review of human–robot coordination control for rehabilitation based on motor function evaluation

As a wearable and intelligent system, a lower limb exoskeleton rehabilitation robot can provide auxiliary rehabilitation training for patients with lower limb walking impairment/loss and address the existing problem of insufficient medical resources. One of the main elements of such a human–robot coupling system is a control system to ensure human–robot coordination. This review aims to summarise the development of human–robot coordination control and the associated research achievements and provide insight into the research challenges in promoting innovative design in such control systems. The patients’ functional disorders and clinical rehabilitation needs regarding lower limbs are analysed in detail, forming the basis for the human–robot coordination of lower limb rehabilitation robots. Then, human–robot coordination is discussed in terms of three aspects: modelling, perception and control. Based on the reviewed research, the demand for robotic rehabilitation, modelling for human–robot coupling systems with new structures and assessment methods with different etiologies based on multi-mode sensors are discussed in detail, suggesting development directions of human–robot coordination and providing a reference for relevant research.     

An optimal fuzzy-PI force/motion controller to increase industrial robot autonomy

This paper presents a method for robot self-recognition and self-adaptation through the analysis of the contact between the robot end effector and its surrounding environment. Often, in off-line robot programming, the idealized robotic environment (the virtual one) does not reflect accurately the real one. In this situation, we are in the presence of a partially unknown environment (PUE). Thus, robotic systems must have some degree of autonomy to overcome this situation, especially when contact exists. The proposed force/motion control system has an external control loop based on forces and torques exerted on the robot end effector and an internal control loop based on robot motion. The external control loop is tested with an optimal proportional integrative (PI) and a fuzzy-PI controller. The system performance is validated with real-world experiments involving contact in PUEs.     

基于强化学习的机器人手臂仿人运动规划方法

面向人-机器人交互共融环境对机械臂仿人运动规划的重大需求,本文提出了一种基于强化学习的机器人手臂仿人运 动规划方法。 首先,基于人体手臂的结构特征,设计了体现机械臂运动特性的肩夹角、肘夹角和腕关节运动角,并采用正态性和 相关性分析方法,对 VICON 运动捕捉系统获取的人体手臂运动数据进行分析,以获取人臂运动特性规则。 然后,根据不同的运 动特性规则,设计对应的回报函数,并采用强化学习方法进行机械臂仿人运动模型的训练。 最后,搭建机械臂仿人运动平台,实 验统计仿人运动的成功率为 91. 25% ,验证了所提规划方法的可行性和有效性,可用于提高机械臂运动的仿人性。     

体感控制的上肢外骨骼镜像康复机器人系统

为辅助患肢进行自主康复训练,研制了一种体感控制的上肢外骨骼镜像康复机器人系统。设计了可穿戴式三自由度上肢康复机械臂,利用Kinect传感器提取人体6个骨骼关节点数据,计算所需控制参数,将健肢的体势动作转化为控制信号,控制机械臂带动患肢做镜像或同步运动康复训练。搭建了上肢外骨骼康复机器人系统实验平台,分别进行了单关节镜像控制和多关节联动同步控制穿戴实验,系统具有良好的体感控制随动性能,能满足上肢康复训练的要求。     

Vision guided dual arms robotic system with DSP and FPGA integrated system structure

Usually, a humanoid robot has two arms and stereo vision system to execute human daily actions. It has complicate mechanism and mechatronics control system structure. The hardware control structure should be planned ingeniously to execute the complicate computation of 3D image processing and manipulate a multi degree of freedom dual arms motion control, especially for mobile robot system. Here a 7 DOF dual arms robot with FPGA hardware control structure and a digital signal processor (DSP) based CMOS stereo vision system are designed and built in our lab. The intelligent fuzzy sliding mode control strategy is employed to establish the visual guided robotic motion control software. This low cost humanoid robotic system has compact control structure and mechanism integration for mobile application purpose. Object detecting and tracking schemes in 3D space were developed for locating the target position and then guided the robot arm to pick and place objects or track the specified moving target. Experimental results show that this delicate robotic system has basic humanoid function.     

Fundamental problems in rehabilitation robots based on neuro-machine interaction

Study results in the last decades show that amount and quality of physical exercises,then the active participation,and now the cognitive involvement of patient in rehabilitation training are crucial to enhance recovery outcome of motor dysfunction patients after stroke.Rehabilitation robots mainly have been developed along this direction to satisfy requirements of recovery therapy,or focused on one or more of the above three points.Therefore,rehabilitation robot based on neuro-machine interaction has been proposed for the paralyzed limb training of post-stroke patient,w hich utilizes motor related EEG,UCSDI(Ultrasound Current Source Density Imaging),EM G for the robot control and feeds back the multi-sensory interaction information such as visual,auditory,force,haptic sensation to the patient simultaneously.This neuro-controlled and perceptual rehabilitation robot w ill bring great benefits to post-stroke patients.In order to develop such a kind of rehabilitation robot,some key technologies,such as noninvasive precise measurement and decoding of neural signals,realistic sensation feedback,coordinated control for both the rehabilitation robot and the patient,need to be solved.In this paper,some fundamental problems in developing and optimizing such a kind of rehabilitation robot based on neuro-machine interaction are proposed and discussed.     

Generation and Simulation of Robot Trajectories in a Virtual CAD-Based Off-Line Programming Environment

This paper presents a new approach to the generation and optimisation of the position and orientation trajectories in Cartesian task space, and simulation in a virtual CAD-based off-line programming environment. A novel concept of the robot pose ruled surface is proposed, and defined as a motion locus of the robot orientation vector, i.e. the vector of equivalent angular displacement. The planning for trajectories of robot end-effectors can be accomplished by generating the robot pose ruled surface and optimising its area under the constraints with good kinematics and dynamics performances. The established optimisation model is based on functional analysis and dynamics planning, and is simplified by using high-order polynomial space curves as the robotic position and orientation trajectories. The developed system, RoboSim, is a virtual integrated environment which can be used as a testbed for automatic motion planning and simulation for robots. Two examples are given to verify the feasibility of the proposed approach and models, and to demonstrate the capabilities of generation, optimisation, and simulation modules and libraries in the RoboSim package. The simulation results show that the approach and system are feasible and useful for motion planning, performance analysis and evaluation, and CAD-based prototyping and off-line programming in both the virtual and the real design and planning environment.     

步行康复机器人轨迹控制方法研究

为了满足神经受损患者步行康复训练需要,设计了以外骨骼助行腿为核心的步行康复机器人,其重要的要求是保证机器人的运动轨迹符合患者康复训练要求。为使机器人能模拟步态为患者提供康复训练,在合理的步态规划后对轨迹的控制方法进行了研究,在控制系统软、硬件平台上完成了步行康复机器人助行腿的两种轨迹控制方式(位置控制和速度控制)。通过实验验证了控制方式的可行性,满足了患者步态训练需要。同时实验结果表明,速度控制方式比位置控制方式更加适合步行康复机器人。     

软质肘关节外骨骼的肌力矩估计与神经网络补偿协调控制

为辅助偏瘫患者进行多模式肘关节康复训练,研制了一种软质肘关节康复外骨骼机器人,并提出了一种基于人体肌力矩估计与自适应神经网络补偿的协调控制策略。利用表面肌电信号来识别人体的运动意图并调整康复训练轨迹,采用Lyapunov方法证明了控制算法的闭环控制稳定性。搭建了实时控制实验平台,并开展了基于运动意图的轨迹跟踪实验与自由主动训练实验。实验结果表明,所提控制策略能保证被动训练过程的轨迹跟踪精度,并且可以根据患者的运动意图调整主动训练过程的运动轨迹,实现不同强度的主动康复训练。     

微小研抛机器人开放式控制系统研究

提出在大型模具曲面上进行自主研抛作业的微小机器人的运行特征,建立了一种基于PMAC和PC的双CPU开放式控制系统.通过对伺服运动、研抛执行和传感定位子系统的分析,全面介绍了系统体系结构和控制策略,运动实验结果表明了系统的可行性.该微小研抛机器人控制系统的设计符合实用要求,具有一定应用价值.     

基于人机耦合模型的上肢康复外骨骼闭环PD迭代控制方法

针对多关节上肢外骨骼重复性康复训练非线性求解困难问题,提出了一种闭环PD迭代学习控制方法。基于人体工学确定了六自由度上肢外骨骼康复机械臂的参数、自由度配置与关节运动范围。以人机交互力为耦合方式,建立了基于牛顿-欧拉法的人机耦合模型,完成了人机耦合动力学模拟分析。基于迭代学习控制理论提出外骨骼康复机械臂的闭环PD迭代学习控制方法,通过建模仿真分析了肩关节/肘关节迭代学习控制的轨迹误差、人机交互力和驱动力矩。第三次迭代后的轨迹误差小于0.05 rad,PD迭代学习控制器的输出对系统控制进行了有效的补偿,提高了系统状态的稳定性。研制了六自由度上肢外骨骼康复机械臂样机,开展试验测试。试验结果表明,随着控制试验在迭代域上的运行,系统的输出向着期望的系统状态转化,所提出的迭代学习控制算法可以提高上肢外骨骼康复训练重复性运动的控制精度,进而提高人机交互性能。     

ADDITIONAL DESIGN FEATURES OF A MASTER–SLAVE CONTROL SYSTEM WITH FORCE SENSING AND ENERGY RECYCLING FOR UPPER LIMB REHABILITATION ROBOTS

Traditional upper-limb rehabilitation robots usually realize force feedback with force sensors or impedance controllers. Otherwise, assistant or resistant force required in different training modes is given by the robot, which does not motivate the initiative of patients sufficiently. This article introduces a self-controlled upper-limb rehabilitation robot to implement force sensing without a force sensor or an impedance controller. The system supports bimanual exercises in different training modes with one limb providing a proper force for the contralateral limb. The above characteristics and the capability of master–slave motion tracking with a kind of energy recycling were verified with preliminary experiments.     

Dynamic cutting force modeling and experimental study of industrial robotic boring

In this paper, a new approach based on industrial robotic boring is proposed to solve problems associated with intersection holes during aircraft assembly. A model is established to predict the dynamic cutting force of a robotic machining system. The robot stiffness coupling, chip deformation, and plowing interference affecting the cutting force are considered using the principles of cutting mechanics and the Oxley orthogonal cutting model. By solving a numerical solution of motion differential equation, the cutting force components in the radial, tangential, and feed directions are obtained by the model. In addition, an advanced curve intersection method is developed to identify the instantaneous uncut chip area and cutting edge contact length. Verification tests were performed on an ABB-IRB6600-175/2.55 robot for titanium alloy TC4 to determine the accuracy of the predictions. The results show that the simulated and measured cutting forces were in good agreement under different cutting conditions. By analyzing simulated and experimental results, we show that the model can be applied to predict the occurrence of vibration and has application value in terms of suppressing vibration during robotic boring.     

Design of active orthoses for a robotic gait rehabilitation system

An active orthosis (AO) is a robotic device that assists both human gait and rehabilitation therapy. This work proposes portable AOs, one for the knee joint and another for the ankle joint. Both AOs will be used to complete a robotic system that improves gait rehabilitation. The requirements for actuator selection, the biomechanical considerations during the AO design, the finite element method, and a control approach based on electroencephalographic and surface electromyographic signals are reviewed. This work contributes to the design of AOs for users with foot drop and knee flexion impairment. However, the potential of the proposed AOs to be part of a robotic gait rehabilitation system that improves the quality of life of stroke survivors requires further investigation.     

6R型串联机器人控制系统的软件实现

基于Windows系统平台和VC6．0编程环境,结合ACR9000运动控制器实现了机器人模块化控制系统的设计。整个系统能够实现机器人示教、机器人运动指令生成、指令识别与运动再现以及运动状态监控等功能。此控制系统在自主研发的多功能6R型串联机器人平台上运行平稳。     

Multi-axis motion controller for robotic applications implemented on an FPGA

This paper presents the design of a field-programmable gate array (FPGA)-based motion controller for robotic applications. In contrast to digital signal processor and microprocessor implementations, the control period of this system is fixed. Foregoing implementations on FPGA require microprocessor-based platforms for data interchange tasks consuming a large amount of resources; consequently, they could not be implemented on low logic density devices, or they use IP cores which limits the implementation of the system to only certain device families. This new motion controller architecture integrates control and communication modules in a single chip which permits an increase to the number of axis according to the system requirements. The proposed design presents a low consumption of logic resources; therefore, a considerable cost saving per axis is achieved. The system test has been carried out with a three-degree of freedom selective compliant assembly robot arm robot and a standard PC as master device. The digital filter parameters have been tuned by using a crossover frequency method. Step and profiled motion responses obtained show very good performance.