【作者】 张佳帆；

【导师】 陈鹰； 杨灿军；

【作者基本信息】 浙江大学 ， 机械电子工程， 2009， 博士

【摘要】 近几年来,柔性外骨骼人机智能系统已成为机器人技术、机电工程、自动控制、生物工程以及人工智能等学科领域中一个新的研究热点,并在科研、工业生产、太空或深海探索、娱乐、运动康复和日常生活中逐步得到了广泛地应用。柔性外骨骼人机智能技术以人机一体化技术为核心,充分发挥人和智能机器各自的优势,通过在感知、决策以及执行层面上有机的人机耦合,增强系统的性能。遥操作外骨骼和增力型外骨骼是柔性外骨骼人机智能系统的两个重要研究方向。近几年来国内外相关领域的技术研究和相关产品开发表明,柔性外骨骼人机智能系统具有极大的基础科学研究意义和应用前景。“可穿戴”是柔性外骨骼最主要的特点,因此,在柔性外骨骼结构设计过程中必须遵循拟人化,不仅在运动形式上需要保持一致,而且在运动自由度分布上也应一致,保证穿戴者(人)与柔性外骨骼的运动一致性,由此,可通过D-H参数方法建立人的肢体和外骨骼系统的多刚体串联运动学模型。在此模型基础上,分析人体上肢神经肌肉运动及感知机理,并建立人体上肢神经肌肉及各关节的运动模型,选用3RPS并联机构实现肩关节3自由度运动,可充分保证6自由度上肢柔性外骨骼机械手可柔顺地跟随操作者的上肢运动。根据人体下肢运动关节自由度分布及运动机理,设计了由直流伺服电机与滚珠丝杠构成关节直线驱动器来模拟关节运动骨骼肌的4自由度下肢外骨骼系统。并通过对人体下肢行走步态进行分析,提出下肢外骨骼系统人机5杆运动学动力学模型。为确保柔性外骨骼在操作的舒适性和安全性,柔性外骨骼与人的接触位置应选择人体上承压能力较好的区域以及不影响关节运动的区域。同时可以通过采用小质量/惯量运动零件、柔性关节、安全限位等安全设计方法,减少意外碰撞过程中外骨骼对人的冲击力,通过对意外碰撞过程中外骨骼对人的冲击力与人的安全临界冲击力之间比较,可以对柔性外骨骼人机智能技术的安全性能进行评价。其次,人机交互控制是柔性外骨骼人机智能系统中体现人机智能耦合的重要组成部分,为此需要人和柔性外骨骼在相互平等的条件下实现感知层中人机信息感知、交互与融合,决策层人机协调控制决策以及执行层人机交互动作。根据上肢柔性外骨骼与下肢运动康复外骨骼的使用目标,分别提出了上肢柔性外骨骼力反馈控制策略以及下肢运动康复外骨骼被动控制、半主动控制以及主动控制三种康复训练控制策略。根据柔性外骨骼人机智能技术中人与外骨骼的协调工作模式,建立系统的n端口网络模型,并通过无源性理论对系统人机交互控制的稳定性作出判别。此外,总线模式的系统通讯网络构架充分保证了柔性外骨骼系统的控制指令和信息传递的准确性和可靠性。而根据系统任务的目标与要求、机器系统模型、人的模型以及工作负荷与匹配信息的动态任务分配模式,充分体现了人与外骨骼之间的协同合作。上肢柔性外骨骼以其卓越的人机信息耦合能力,是实现机械手力反馈主从控制的理想方法。本研究中,根据人体上肢模型及所提出的上肢柔性外骨骼结构,采用正交试验方法对结构参数进行优化设计,保证了上肢柔性外骨骼能够最大范围地适应人体上肢的自由运动。首次提出了对主从机械手的运动空间以及欠运动自由度空间的匹配方法,改善了主从异构机械手在运动奇异点、关节运动极限点等运动空间的控制性能,充分实现了上肢柔性外骨骼与从机械手之间的运动协调。在系统气动力反馈控制结构中,通过分布式的混合模糊控制器克服了气动系统非线性强、控制精度差等困难,采用微型气动系统实时地再现机械手遥操作时感知力信号,控制误差小于5%,增强了操作的真实感。为克服以Internet为信息媒介的遥操作系统由于网络数据传输时变延时对控制稳定性的影响,文中提出了基于多事件的控制结构,改变了原有控制结构仅对从机械手运动稳定性检测的缺点,实行了对主从异构机械手遥操作过程中主从机械手的运动状态及控制过程中不确定因素的检测,改善了机器人远程操作系统受时变网络延时的影响。此外,本研究工作中采用膜模型和弯曲梁模型对弯曲气动肌肉弯曲变形与输出力矩关系进行了建模,设计开发了基于弯曲气动肌肉的单自由度力反馈手肘关节外骨骼,在实验中成功实现了对0.5Hz力信号的跟随,稳态误差控制小于1.5%。下肢运动康复训练外骨骼是柔性外骨骼人机智能系统向非制造业、服务业,尤其是医疗领域应用的重要拓展。根据下肢外骨骼的结构设计方案,从工程角度对下肢运动康复外骨骼系统软、硬件予以实现。在开创性地引入5杆运动学动力学模型的基础上,分别对被动控制策略和半主动控制策略予以研究。康复患者训练数据库改变了卒中及瘫痪患者原有的定性非定量的训练模式,实现了患者的数字化康复训练。本研究中所研制的原型样机可根据患者病情带动患者进行15分钟以上的连续训练,并可以在0 km/h～2 km/h范围内调节训练步速,减轻了传统康复训练模式中理疗师的工作负担。在系统功能测试及正常人实验研究中,正常工作率达到近95%,充分证实了系统的安全性和可靠性,以及控制策略的可行性。最终的卒中及瘫痪患者实验结果成功地表明系统在决策层、感知层和执行层实现患者(人)与下肢外骨骼作为一个整体的协调运动,充分说明了本论文所提出的柔性外骨骼仿生设计机理以及人机交互控制理论的准确性。本研究工作的成果对于我们今后更为深入的理论研究和开发实践具有承上启下的作用,所提出的关键技术及其解决方法具有很好的借鉴和参考价值。更多还原

【Abstract】 The exoskeleton-type system is a kind of man-machine system centered by human.It is always designed as an external mechanical structure whose joints correspond to those of human body or limbs.It combines the human intelligence and the machine power so that it enhances the intelligence of the machine and the power of the human operator.As a result,the human operator can achieve what he is not capable of by himself.Robot tele-operation and human power augmentation are its two prominent applications.In recent years,the exoskeleton-type systems have been developed rapidly accompanied with great achievements in mechanical and electronic engineering,automation technology,biological,and material science.This reveals that the exoskeleton-type systems have a nice prospect for daily-life application and significance in science research.The work of this paper is to provide a comprehensive discussion of the exoskeleton-type system on the viewpoint of man-machine system.The wearability is the main characteristic of the exoskeleton-type system.The structure of exoskeleton should be anthropomorphic and ergonomic,not only in shape but also in function and in the distribution of the DOF as well.Due to identity motion between the human operator and the exoskeleton,the kinematic model of the exoskeleton-type system can be described by D-H method. By investigating the atlas of the human upper limb during motion,the biomechanical model of human upper-limb can be established.3RPS parallel mechanism was introduced to realize the 3-DOF motion of human shoulder,which excellently promised to track the human upper-limb motion.According to the DOF distribution and anatomy of human lower-extremity,a 4-DOF lower-limb exoskeleton was developed on the linear actuator composed by DC motor and ball-screw.A 5-link kinematic and dynamic model was set up based on the human gait.In order to guarantee the safety and comfort of the exoskeleton-type system,the support were designed to adapted to the morphology of human limb,thus avoiding misalignments between exoskeleton and limb.In addition,the general safety can be evaluated by employing the critical impact force as a minimal impact force that causes injury to humans and giving the definition of danger index as the producible impact force against the critical impact force.Definitely,the impact force can be minimized by means of reducing the mass and inertia of the moving part,using distributed macro-mini actuation and joint compliance,and mounting stop block.Basically,the control architecture of exoskeleton-type systems is quite different from the traditional intelligent robotics.In this control architecture,the human operator is not only the commander or the supervisor of the system,but also a part in the control loop,called ’man-in-the-loop’.This is intuitive that the human operator receives the feedback from environments and optimizes the control target.It puts more emphasis on the combination of the human intelligence and machine power,and their information exchanging,so that the man and the exoskeleton are coupled together and both are irreplaceable.The force feedback control strategy for upper-limb and intelligent control strategy for lower-limb exoskeleton,including passive control, semi-active control and active-control were proposed respectively according to the scopes of these two kinds of exoskeletons.Additionally,an n-port network model is introduced based on the cooperation between the human and the exoskeleton,by which the system stability can be analyzed by passivity.The requirements of application and various different topologies suggest that the most suitable solution for wired networks is a hierarchical bus topology.The function allocation between the human and machine should be handled by fully considering the goal,requirements,system model,and working load.Due to the outstanding characteristic of man-machine interaction,the upper-limb exoskeleton is regarded as one of the best methods for robot tele-operation with force feedback.According to the biomechanical model of human-upper limb,optimal mechanical design was carried out by orthogonal experiment method.Due to the different structure between the exoskeleton-type master arm and robotic slave arm,a universal workspace mapping with deficient-DOF space was proposed. Some small sized pneumatic cylinders were chosen as the actuators for force feedback.The distributed hybrid fuzzy control architecture was figured out to realize the pneumatic force-feedback control,by which the tele-operation became more intuitive.In order to minimize the influence of the time-variable time delay in the process of data transmission on internet,a multi-event-based control method was utilized.The stability and unexpected factors in control process of the master exoskeleton and the slave robot arm were both monitored.Additionally,some pre-study on the curved PMA based elbow exoskeleton for force feedback control were made.The rehabilitation is an important application of the power augmentation exoskeleton.We implemented technical solution of a lower-limb exoskeleton system in light of the biomechanical model of human lower-limb.Mechanical structure was optimal designed according to the simulation results based on the 5-link model.The passive position control strategy was arranged as the simplest control method for the gait.Additionally,a 5-link model based semi-active trajectory adjusting control strategy was explored to further improve the performance of such a man-machine system.With the exoskeleton and different control strategy,physiological gait patterns and training information were obtained and restored in the database.8 healthy subjects and a paraplegic patient participated in the test experiments respectively and the results were encouraging.By the successful implementation of these two kinds of exoskeleton-type system,the basic principle of the biomechanical design and theory of the system control were verified.The work introduced in this paper has significance in the development of exoskeleton-type system in near future.更多还原