Pneumatic interactive gait rehabilitation orthosis: design and preliminary testing

Motor rehabilitation techniques based on passive movement of the lower limbs have been developed over the past 15 years. Gait training automation is the latest innovation in these techniques. This paper describes the design and development of a pneumatic interactive gait rehabilitation orthosis (PIGRO), as well as the first experimental results obtained with healthy subjects. PIGRO consists of a modular and size-adaptable exoskeleton, pneumatic actuation systems for the six actuated degrees of freedom (DoF), and a control unit. The foot orthosis and ankle actuation can be removed and/or replaced with orthopaedic shoes so as to permit gait rehabilitation while advancing between parallel bars with ground contact and partial body weight support (i.e. not walking in place). Control logic provides closed-loop position control independently on each joint, with position feedback for each joint in real time. Imposed curves are physiological joint angles: it is also possible to choose between activating one or both legs and to modify curves to obtain different gait patterns if required. The paper concludes with a presentation of experimental results for the device's performance.     

基于伪刚体模型的腰部训练装置的运动学分析

考虑到康复运动过程中康复患者对康复机器人的作用,康复机器人的设计过程中将康复患者的康复部位作为其一部分进行设计和分析。将腰部考虑成柔性杆,并将其作为气动人工肌肉驱动的腰部训练装置的一部分进行分析。对腰部训练装置进行了结构介绍并分析了腰部在腰部训练装置中的作用,给出了腰部训练装置的运动学模型。对腰部训练装置进行了受力分析,结合腰部训练装置的功能对气动人工肌肉组件进行了设计和受力分析,使用伪刚体模型对腰部进行受力分析,得到了腰部脊柱与康复腰带结合点的受力结果,基于此对腰部训练装置整体进行受力分析,得到腰部训练装置中康复腰带与气动人工肌肉组件之间受力的关系。通过仿真验证了运动学分析和受力分析结果的正确性,并根据腰部训练装置的力学分析及仿真结果,进一步设计并搭建气动人工肌肉和柔索混合驱动并联腰部康复机器人试验平台。     

基于气动人工肌肉的六自由度运动平台

实现六自由度机构准确、稳定运动控制的关键在于执行元件的控制特性以及动力学模型的准确表达。在分析一般六自由度平台特性的基础上,建立了气动人工肌肉双三角六自由度并联运动平台,运用Matlab进行运动学分析,生成机构运动空间。对所建模型进行运动模拟,根据仿真计算数据得到气动人工肌肉的运动特性,进而提出控制方法。     

带卸压槽的微摩擦气缸Fluent仿真分析

针对超低频模态测试悬挂系统中微摩擦气缸抗侧向能力不足的问题,提出一种在活塞尾部增加环形卸压槽的新结构。建立了活塞外表面与气缸内表面之间气膜流场特征参数的仿真模型,并进行Fluent仿真计算,结果表明,增加环形卸压槽改善了气膜的气压分布,在两排节流孔之间形成了具有一定宽度且稳定的承载区,使活塞的轴线与气缸的轴线基本保持平行,提高了抗侧向能力及气膜刚度,从而使气缸工作更为稳定。试验结果进一步验证了仿真结果,证明带环形卸压槽的微摩擦气缸的性能得到了提高。     

Re-analysis of the degree-of-freedom configuration of the platforms in spatial parallel mechanisms with constraints spaces

The degree-of-freedom (DoF) configuration of a mechanism, which is an important concept in the field of mechanisms and is the key problem to be solved before mechanisms are designed, has been discussed in our previous article [1]. In this paper, we will further analyze the DoF configuration of the platforms of spatial parallel mechanisms with constraints spaces. According to the physical meaning of reciprocal screws, we can solve the constraints spaces spanned by reciprocal screws, and then solve the free mobility spaces of the platform and its DoF configuration. With this methodology, not only can we differentiate the system from its members, but we also extend the concept of DoF configuration, which should have the attributes of number, type, and direction.     

双滑块机构在爬升机械手中的应用

本机构由两组曲柄滑块机构串接而成,双作用气缸驱动。实现机械手的主爬升运动。本机构结构简单,动作灵活,可以实现正反爬升动作,能在气缸较小的行程内实现大的爬升距离。并具有力的放大作用。给出了机构的结构原理、机构尺度与行程的关系,以及驱动力的计算方法。     

Adaptive Robust Tracking Control of Pressure Trajectory Based on Kalman Filter

When adaptive robust control(ARC) strategy based on backstepping design is applied in pneumatic servo control, accurate pressure tracking in motion is especially necessary for both force and position trajectories tracking of rodless pneumatic cylinders, and therefore an adaptive robust pressure controller is developed in this paper to improve the tracking accuracy of pressure trajectory in the chamber when the pneumatic cylinder is moving. In the proposed adaptive robust pressure controller, off-line fitting of the orifice area and on-line parameter estimation of the flow coefficient are utilized to have improved model compensation, and meanwhile robust feedback and Kalman filter are used to have strong robustness against uncertain nonlinearities, parameter fluctuations and noise. Research results demonstrate that the adaptive robust pressure controller could not only track various pressure trajectories accurately even when the pneumatic cylinder is moving, but also obtain very smooth control input, which indicates the effectiveness of adaptive model compensation. Especially when a step pressure trajectory is tracked under the condition of the movement of a rodless pneumatic cylinder, maximum tracking error of ARC is 4.46 kPa and average tracking error is 0.99 kPa, and steady-state error of ARC could achieve 0.84 kPa, which is very close to the measurement accuracy of pressure transducer.     

多模式柔顺膝关节康复器设计及力分析

研究开发了一种多模式柔顺膝关节康复器,提出了无杆气缸+气动柔性驱动器的复合驱动技术,保证了对膝关节康复训练柔顺性和大行程的要求.设计了康复器的结构和控制系统的软、硬件,并对康复器的驱动力进行了分析.所研发的康复器可实现膝关节主动、被动等多种模式的康复训练.     

基于微分几何的并联机构动力学及复合控制

在应用微分几何和黎曼度量分析串联机构动力学模型的基础上,结合并联机构的特点,推导了简单、统一的并联机构动力学模型,并将其投影到约束力和切向力方向,进而提出了并联机构的力/位置复合控制的控制算法。对一个二自由度平面并联机构的仿真结果表明,所提出的算法可有效控制约束内力、外力和末端位置。     

Position control of a rodless cylinder in pneumatic servo with actuator saturation

In this paper, positioning control of a rodless cylinder in pneumatic servo systems with actuator saturation is investigated via an active disturbance rejection control. A linear extended state observer is designed to estimate and compensate strong friction force and other nonlinearities in the pneumatic rodless cylinder system. An actuator saturation linear feedback control law is developed to further improve the control performance. Furthermore, a linear matrix inequality-based optimization algorithm is employed to estimate a strictly invariance set for the closed-loop system. Experiment results with response time 0.5 s and accuracy 0.005 mm for a 200 mm step signal demonstrate the effectiveness of the proposed control strategy.     

驱动支链完全解耦的可重构踝关节康复并联机构型综合

基于术后6～12周内的前、中、后期踝关节扭伤的康复运动需求,提出具有三种康复运动模式的可重构踝关节康复并联机构。首先,针对胫距关节和距下关节的轴线运动特征,研究踝关节康复运动切换机理和“双心”特性,提出符合踝关节自由度和轴线运动特性的六种融合支链;根据构型约束支链的选取方案,筛选出四种无约束支链。其次,基于旋量理论对六种融合支链进行过约束设计,验证符合实际需求的融合支链;根据传递力旋量与动平台运动轴线关系,提出一种驱动支链完全解耦优化方法,得到三种无约束驱动支链以及十二种机构构型,使得机构在三种康复模式中实现完全解耦。最后,通过ADAMS仿真验证机构的三种运动分支及完全解耦的正确性。可重构踝关节康复机器人依据患者康复需求采取对应康复模式,适用范围广,针对性强,控制简单。     

气压位置控制系统研究现状及展望

回顾了气压位置控制系统的研究历史,总结了在基本特性研究、控制阀开发和控制策略研究方面的工作。研究工作表明：气体通过阀口和管道的流动复杂、缸内热力过程为指数变化的多变过程、摩擦力与系统运动速度、驱动压力和背压有关。在开发了相关控制阀后,进行了针对系统的各种特性的控制策略的研究,如针对非线性的非线性补偿措施、针对摩擦力的振颤补偿、针对模型误差的鲁棒设计和针对开关阀系统的同向PWM设计等,效果明显。研究工作使得气压位置控制系统已具有良好的性能,能满足工业生产的需要。     

3-PRC并联机器人机构运动和力传递性能分析

以3平移自由度3-PRC并联机器人机构为研究对象,建立了机构的运动方程;基于速度与力可操作椭球,建立运动与力各向同性评价指标,度量机构在操作空间给定位置处运动与力的传递性能;以速度和力方向可操作度为评价指标,度量机构在操作空间沿指定方向运动与力的传递能力.结果表明,3-PRC并联机器人机构在操作空间具有良好的运动与力的传递性能.     

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.     

Design and implementation of a novel modal space active force control concept for spatial multi-DOF parallel robotic manipulators actuated by electrical actuators

Robotic spine brace based on parallel-actuated robotic system is a new device for treatment and sensing of scoliosis, however, the strong dynamic coupling and anisotropy problem of parallel manipulators result in accuracy loss of rehabilitation force control, including big error in direction and value of force. A novel active force control strategy named modal space force control is proposed to solve these problems.Considering the electrical driven system and contact environment, the mathematical model of spatial parallel manipulator is built. The strong dynamic coupling problem in force field is described via experiments as well as the anisotropy problem of work space of parallel manipulators. The effects of dynamic coupling on control design and performances are discussed, and the influences of anisotropy on accuracy are also addressed. With mass/inertia matrix and stiffness matrix of parallel manipulators, a modal matrix can be calculated by using eigenvalue decomposition. Making use of the orthogonality of modal matrix with mass matrix of parallel manipulators, the strong coupled dynamic equations expressed in work space or joint space of parallel manipulator may be transformed into decoupled equations formulated in modal space. According to this property, each force control channel is independent of others in the modal space, thus we proposed modal space force control concept which means the force controller is designed in modal space. A modal space active force control is designed and implemented with only a simple PID controller employed as exampled control method to show the differences, uniqueness, and benefits of modal space force control. Simulation and experimental results show that the proposed modal space force control concept can effectively overcome the effects of the strong dynamic coupling and anisotropy problem in the physical space, and modal space force control is thus a very useful control framework, which is better than the current joint space control and work space control.     

Modelling and identification of industrial pneumatic drive system

A model and an identification method appropriate for typical industrial, open-loop controlled, pneumatic systems are presented in this paper. The development of the mathematical model takes into consideration nonlinear flow through extended pneumatic circuits, direction dependent friction, dead volume in cylinder chamber, fittings and piping, leakage between actuator chambers, time delays due to valve switching and long lengths of tubing, polytropic temperature model and heat transfer. The identification method is evolved with a view to apply in industrial environments and takes careful consideration of flow characteristics of both charge and exhaust elements of the circuit. Model validation is presented for a standard double-acting asymmetric cylinder with different payloads. The results of the residual analysis indicate an improved system model in comparison to the published literature. The approach presented should therefore be useful in simulation-based design and analysis of pneumatic systems. It is also applicable in the development of servo-pneumatic systems.     

新型全液压重载锻造机器人机构设计及分析

针对全液压重载锻造机器人载荷大、搬运速度快和定位精度高的特点提出了一种新型机构方案,该方案能够实现车身回转、夹钳伸缩、夹钳升降、夹钳回转和钳头夹紧五个自由度的运动,其运动主体为一种混联机构,由三组平行四边形连杆机构构成,采用三组液压缸并联驱动,可有效增大机器人工作空间,使负载分配合理,易于控制。建立了运动学和动力学模型,采用正弦曲线将机器人夹钳末端的位移规划为直线运动,在MATLAB中求解出机器人的工作空间,得到了直线运动下各组液压缸的位移和驱动力变化曲线,验证了该模型的正确性和机构的合理性,为重载锻造机器人机构设计提供了一种解决方案。     

5-DOF上肢康复机械臂交互式康复训练控制策略

设计一种5-DOF穿戴式偏瘫上肢康复机械臂系统,提出被动和主动两阶段的交互式康复训练控制策略。在被动训练中,根据偏瘫患者上肢单侧受损的特点,提取偏瘫患者的健侧上肢4块肌肉的表面肌电信号(Surface electromyogram, sEMG) 作为康复机械臂的控制信号,利用AR参数模型和BP神经网络来理解患者的运动意图,驱动机械臂辅助患侧上肢实现特定的康复训练动作。在主动训练中,通过实时获取各关节力矩信号来判断人体上肢的运动所产生的作用力方向与大小,并利用比例控制器和运动学雅可比逆矩阵控制康复臂末端速度、驱动各关节运动。试验结果证明了提出方法的正确性和有效性。     

基于虚拟现实技术的三自由度上肢康复机器人系统

研究了一套基于虚拟现实技术的3自由度上肢康复机器人系统.机器人传递运动部分采用连杆机构和3重轴;控制单元采用数字信号处理器（DSP）,绝对式编码器采集各轴旋转位置、方向信息,磁粉制动器实现各轴的负载、制动;人机交互方面,患者操作机器人末端手柄做虚拟现实技术开发的虚拟游戏.该系统能够提高患者的主动性和实现3自由度康复训练运动.     

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。