基于变刚度驱动的下肢外骨骼

针对传统刚性驱动的外骨骼在复杂人机交互环境中柔顺性不足、无法保证人体安全等问题，设计一种变刚度下肢外骨骼用于康复训练。提出了一种可重构的变刚度原理，通过调整关节弹簧的预紧力来实现关节刚度的改变，同时通过滑轮组的重构来增大外骨骼的刚度调整范围。基于所提出的可重构变刚度原理，设计了用于驱动外骨骼主动关节的变刚度执行器，并进一步设计了变刚度下肢外骨骼的机械结构。建立了外骨骼的理论刚度模型，并对其刚度特性进行了仿真分析。搭建了变刚度下肢外骨骼的试验平台，对样机的刚度特性进行了试验验证。结果表明，试验得到的刚度曲线与理论模型吻合。基于变刚度驱动的扭矩-偏角特性，提出一种无交互力传感器的外骨骼行走跟随控制方法，并在不同速度下进行了行走跟随试验。试验结果表明，外骨骼与人体的最大交互力矩为0.8243 N·m，证明外骨骼可以跟随人体运动。     

绳驱动柔性上肢外骨骼机器人设计与控制

为了提高上肢外骨骼机器人的拟人化程度及关节柔性,设计了一种由串联弹性驱动器和鲍登线驱动的4自由度柔性上肢外骨骼机器人.首先,设计一种六连杆双平行四边形机构,建立肩关节虚拟转动中心,满足人体肩部3自由度运动需求.然后,设计基于串联弹性驱动器和鲍登线的驱动模块,将驱动器和机器人关节分离,降低结构的复杂度,减轻关节质量,实现力矩/位置信息的反馈.最后,构建机器人运动学及动力学模型,设计关节阻抗控制器并对样机肘关节进行阻抗控制实验.由实验结果可知,刚度系数在0.5 N·m/(°)～1.5 N·m/(°)时,力矩跟踪均方根为0.33 N·m;阻尼系数在0.001 N·m·s/(°)～0.01 N·m·s/(°)时,力矩跟踪均方根为0.57 N·m.实验结果表明,调节阻抗控制器中的阻抗系数能够改变关节的刚度和阻尼特性,从而提高人机连接的柔顺性.因此该机器人可以满足康复训练需求.     

基于18-传感器数据手套手部交互模型的建立

虚拟现实技术应用到遥操作机器人系统中可以克服通信时延对系统的影响,其交互设备数据手套用作遥操作机器人系统的主端控制装置可以在人机交互中充分发挥手的自然性和灵巧性.介绍了美国Immersion公司生产的CyberGlove的特点及使用方法,接着分析了人体手部的生理结构,将手部运动自由度分解为手部姿态22个自由度和空间位置6个自由度.在建立虚拟手部模型的基础上,以具有18个传感器的数据手套作为手势输入设备,通过人体手部运动学模型建立了数据手套与虚拟手模型之间的联系,利用3DS MAX、OpenGL编程实现了人手与虚拟手模型的交互操作.     

具有手指外展辅助功能的康复机器人系统

手指外展是改善脑卒中患者手部功能最重要的运动之一,目前国内外柔性手部康复机器人的研究主要聚焦在手指的屈伸上,忽略了手指完全外展的重要性。为实现更好的康复效果,研制了一款具有手指外展辅助功能的康复机器人系统。基于热塑性聚氨酯(TPU)薄膜涂层织物设计了一种新型外展驱动器。推导出外展驱动器一般力学方程,以表征其输出力矩与几何参数和内部气压的函数关系。性能分析结果表明,该驱动器可以在较低的气压下提供足够的外展力,具有辅助手指外展的可行性。招募了10名健康受试者进行日常生活活动(ADL)实验,在肌电信号监测下,验证了外展驱动器的辅助作用。此外,提出的康复系统将手部康复机器人与多功能被动训练模式相结合,通过配套软件,为脑卒中患者提供了更高效的康复训练。     

基于混合驱动的柔顺性触觉接口装置

针对目前柔顺性触觉接口设备存在的容易失真的问题,提出了一种基于电机和磁流变液混合驱动的柔顺性触觉接口装置。在简单介绍了磁流变液的基础上,讨论了基于磁流变液被动驱动器的结构和原理,该驱动器采用多转子设计思路以增大力输出范围。利用磁流变液驱动器能够模拟肌体组织的黏滞性,电机能够模拟肌体组织的弹性,将驱动器与电机串联实现肌体组织的柔顺性再现,同时利用电机补偿驱动器非有益阻尼力,增强装置的保真效果。在此基础上设计了柔顺性触觉接口装置,对装置模拟自由空间、不同的变形程度柔顺性物体受力进行了介绍,分析了装置的控制方法,最后加工了触觉装置原型,开展了不同柔顺度虚拟肌体组织柔顺性再现实验,实验结果验证了所设计装置及控制方法的有效性。     

基于力反馈的手部康复训练装置研究进展

携带力反馈功能的装置进行训练已经成为手功能康复训练的重要手段.详细介绍了典型的用于手部康复训练的力反馈装置,通过对其优缺点进行比较,发现手部康复训练力反馈装置存在安全性要求高、重量较大、功能比较欠缺和实时性差的问题,并提出了相应的解决思路.最后展望了手部康复训练力反馈装置的发展趋势.     

单自由度康复训练机器人的虚拟环境设计

提出并建立了一个可用于机器人辅助康复训练的虚拟环境.虚拟环境可以提供视觉反馈,将患者控制训练机械臂的运动映射为虚拟环境中的物体的运动,并采用虚拟力势场的方法,通过机械臂为患者提供相应的力反馈.最后,利用单自由度康复训练系统对一名健康男性进行了初步的实验研究.结果表明,该系统可以实现康复训练过程中的视觉和力觉交互,为患者提供暗示和帮助,在康复训练机器人领域有一定的应用前景.     

面向助力膝关节外骨骼的弹性驱动器研制及实验研究

为满足下肢助力外骨骼不同行走模式下有效驱动的需求,提出了一种弹性驱动器,通过电机带动丝杠螺母串联弹簧,结合相应的刹车片,实现弹性驱动器对不同行走模式下的助力膝关节外骨骼的驱动.对弹性驱动器进行工作模式分析及刹车装置的动力学研究.为优选出合适的刹车片材料及弹簧,进行了弹性驱动器的刹车力及弹跳冲击实验.在建立的Solid Works、ADAMS虚拟样机联合仿真平台上对弹性驱动器驱动的膝关节外骨骼进行运动仿真,考察弹簧刚度及等效质量对弹性驱动器工作性能的影响,为下肢助力机器人弹性驱动器的设计提供理论依据.     

基于云平台交互的手部康复训练评估手套

为了协助医生实现远程指导病人进行手部康复训练,提出了一种基于云平台交互的手部康复训练评估手套的设计。该系统利用示教手套采集医生的手部姿势数据,将其通过云平台转发至气动式的康复训练手套,控制康复训练手套执行对应动作以辅助患者同步运动。实验结果表明,该系统具备在线康复训练指导的能力,为提高医护人员工作效率和减轻患者负担提供了一个有效途径。     

基于人机偏差模型的自对齐髋关节外骨骼解耦设计与计算

针对辅助外骨骼,分析了单自由度人机交互中的人机偏差因素,建立人机偏差变量模型,运用自对齐机构设计理论设计外骨骼机构,以提升人机耦合性能.首先,深入分析了单自由度人体生物关节,建立了人体简化模型+人机偏差变量模型的外骨骼设计模型参考.然后,运用自对齐机构设计理论和多自由度关节解耦方法,提出了自对齐人体运动的外骨骼机构设计思路与方法.最后,以下肢髋关节为对象,将髋关节外骨骼解耦为3个单自由度关节,设计了髋关节助力外骨骼的运动形式,并进行了人机耦合下的外骨骼动态静力驱动计算.结果显示,该运动设计使人机偏差交互力变得可控,从理论上证明了髋关节外骨骼机构能够跟随下肢运动并提供自适应人体的驱动助力.     

Design and Control of Five-Fingered Haptic Interface Opposite to Human Hand

This paper presents the design and control of a newly developed five-fingered haptic interface robot named HIRO II. The developed haptic interface can present force and tactile feeling to the five fingertips of the human hand. Its mechanism consists of a 6 degree of freedom (DOF) arm and a 15 DOF hand. The interface is placed opposite the human hand, which ensures safety and freedom of movement, but this arrangement leads to difficulty in designing and controlling the haptic interface, which should accurately track the fingertip positions of the operator. A design concept and optimum haptic finger layout, which maximizes the design performance index is presented. The design performance index consists of the product space between the operator's finger and the hapic finger, and the opposability of the thumb and fingers. Moreover, in order to reduce the feeling of uneasiness in the operator, a mixed control method consisting of a finger-force control and an arm position control intended to maximize the control performance index, which consists of the hand manipulability measure and the norm of the arm-joint angle vector is proposed. The experimental results demonstrate the high potential of the multifingered haptic interface robot HIRO II⁺ utilizing the mixed control method.     

基于力觉交互的高速率精准操作技能训练方法

介绍了用力觉交互技术进行手眼协调高速率精准操作的动作技能训练方法。提出了记录播放和轨迹智能导引两种培训模式。在记录培训模式中,采用PD控制的方法使学员被动感受专家的运动信息。在智能导引纠正模式中,学员主动操作交互设备,计算机根据学员的操作情况控制交互设备输出导引力或纠正力。最后,采用Omega 3DOF建立了具备触觉显示和图形显示功能的“信封靶”描绘技能训练系统样机平台,分析了力模型参数对系统稳定性的影响。实验结果证明了培训方法的可行性。     

Development of a smart handheld surgical tool with tactile feedback

This paper presents a handheld surgical tool adapting a tactile feedback system. The tool consists of a 3-degree-of-freedom (DOF) force sensor and three tactile displays. The sensor is easily embedded in the tool by adopting the capacitive transduction principle. The sensor measures the direction and magnitude of the 3-DOF force applied to the tool tip. The fingertip grasping the tool is stimulated by the tactile display to transmit the contact force information measured by the sensor. The tactile display is actuated by employing a soft actuator technology based on a dielectric elastomer actuator such as a type of electroactive polymer actuator. In this work, a prototype of the tool is designed and fabricated. Its performance is experimentally validated.     

A teleoperation system for micro positioning with haptic feedback

This paper presents the research work on a 1 Degree of Freedom (DOF) macro-micro teleoperation system which enables human operator to perform complex task in micro environment such as cell insertion with the capability of haptic feedback. To reach submicron resolution, a nano-motion piezo actuator was used as the slave robot and a servo DC motor was used as the master robot. Force sensors were implemented at both ends for haptic feedback and a microscope equipped with camera was employed for real-time visual feedback. The hysteresis nonlinearity of the piezo motor was modeled using LuGre friction model and compensated for. A Sliding Mode Based Impedance Controller (SMBIC) was designed at the slave side to ensure position tracking while an impedance force controller was designed at the master side to ascertain tracking of the force. Control parameters were chosen based on Llewellyn stability criteria such that the entire system stays stable against parameter uncertainties and constant time delay. The experimental results demonstrated capability of the proposed control frameworks in desirable tracking of the position and force signals while the entire system remained stable. The results of this study can be used for complex tasks in micron environment such as cell insertion.     

Lyapunov stable displacement-mode haptic manipulation of hydraulic actuators: theory and experiment

In this article, a stable control scheme is designed and experimentally evaluated for haptic-enabled teleoperated control of hydraulic actuators. At the actuator (slave) side, the controller allows the hydraulic actuator to have a stable position tracking. At the master side, the haptic device provides a kind of ‘feel’ of telepresence to the operator by creating a force that acts like a virtual spring, coupling the displacement of the haptic device to the displacement of the hydraulic actuator. In free motion, this virtual spring restricts the operator's hand to move fast when the slave manipulator is behind/ahead in terms of tracking the master manipulator's displacement. On the other hand, when interacting with the environment, the constrained force imposed on the hydraulic actuator is indirectly reflected through this virtual spring force. Extension of Lyapunov's stability theory to non-smooth systems is first employed to prove the stability of the resulting control system. Effectiveness of the controller is then validated via experimental studies. It is shown that the control scheme performs well in terms of both positioning the hydraulic actuator and providing a haptic feel to the operator. The control scheme is easy to implement since very little knowledge about system parameters is needed and the required on-line measurements are actuator's supply and line pressures and displacement.     

Design of a Haptic Interface for a Gastrointestinal Endoscopy Simulation

This paper presents a new design and analysis of a haptic interface for a gastrointestinal endoscopy simulation. The gastrointestinal endoscopy is a procedure in which the digestive tract and organs of a patient are diagnosed and treated using a long and flexible endoscope. The developed haptic interface incorporates two degrees of freedom (DOF), each of which is necessary to describe the movements of an endoscope during the actual endoscopy procedures. The haptic interface has a translational motion mechanism to implement the insertion movement of the endoscope, and a rotational motion mechanism to implement the rotational movement of the endoscope. The endoscope included in the haptic interface is supported by a folding guide to prevent the endoscope from buckling. Force feedback in each direction is provided by wire-driven mechanisms. The developed haptic interface has a workspace, sensitivity, and maximum attainable force and torque enough to simulate the endoscopy procedures such as colonoscopy, upper GI (gastrointestinal) endoscopy, and endoscopic retrograde cholangiopancreatography (ERCP). The developed haptic interface is applied to implementation of a colonoscopy simulation. Performance including force bandwidth is evaluated through experiments and simulation.     

Haptic force control based on impedance/admittance control aided by visual feedback

This paper demonstrates a haptic device for interaction with a virtual environment. The force control is added by visual feedback that makes the system more responsive and accurate. There are two popular control methods widely used in haptic controller design. First, is impedance control when user motion input is measured, and then, the reaction force is fed back to the operator. The alternative method is admittance control, when forces exerted by user are measured and motion is fed back to the user. Both, impedance and admittance control are also basic ways for interacting with a virtual environment. In this paper, several experiments were performed to evaluate the suitability of force-impedance control for haptic interface development. The difference between conventional application of impedance control in robot motion control and its application in haptic interface development is investigated. Open loop impedance control methodology is implemented for static case and a general-purpose robot under open loop impedance control was developed as a haptic device, while a closed loop model based impedance control was used for haptic controller design in both static and dynamic case. The factors that could affect to the performance of a haptic interface are also investigated experimentally using parametric studies. Experimental results for 1 DOF rotational motion and 2 DOF planar translational motion systems are presented. The results show that the impedance control aided by visual feedback broaden the applicability of the haptic device and makes the system more responsive and accurate.

Design and evaluation of an actuated exoskeleton for examining motor control in stroke thumb

Chronic hand impairment is common following stroke. This paper presents an actuated thumb exoskeleton (ATX) to facilitate research in examining motor control and hand rehabilitation. The ATX presented in this work aims to provide independent bi-directional actuation in each of the 5 degrees of freedom (DOF) of the thumb using a novel flexible shaft-based mechanism that has 5 active DOF and 3 passive DOF. A prototype has been built and experiments have been conducted to measure the allowable workspace at the thumb and evaluate the kinematic and kinetic performance of the ATX. The experimental results show that the ATX is able to provide individual actuation at all five thumb joints with high joint velocity and torque capacities. Further improvement and future work are discussed.     

Modeling and System Identification of a Life-Size Brake-Actuated Manipulator

Safety is a critical factor when designing a robotic rehabilitation environment. Whole-limb or life-size haptic interaction would allow virtual robotic rehabilitation of daily living activities such as sweeping or shelving. However, it has been too dangerous to implement such an environment with conventional active robots that use motor, hydraulic, or pneumatic actuation. To address this issue, a life-size 6-degree-of-freedom (DOF) brake-actuated manipulator (BAM) was designed and constructed. This paper details the BAM's system models including mechanisms, kinematics, and dynamics, as well as detailed input and friction models. In addition, a new system-identification technique that utilizes human input to excite the robot's dynamics with unscented Kalman filtering was employed to identify system parameters. Noise sources are discussed, and the model is validated through force estimation with inverse dynamics. Model parameters and performance are compared with other commercially available haptic devices. The BAM shows a significantly larger workspace, maximum force, and stiffness over other devices exhibiting its promise toward rehabilitative applications.