【作者】 耿德旭；

【导师】 赵继；

【作者基本信息】 吉林大学 ， 机械制造及其自动化， 2011， 博士

【摘要】 各类主动关节是仿生机器人及运动机械的关键部件,其结构特征、运动特点、力学特性、驱动能力和控制方法,将决定整机产品的功能和应用水平。随着科技的发展,机器人技术的应用正以前所未有的速度向工业装配、物流、服务和军事领域扩展,对其整体性能提出了更高的要求。尤其是对关节的结构柔性、运动柔性、驱动柔性和柔性控制提出了挑战,迫切需要研发具有综合柔性功能的仿生关节,对环境和操作对象的变化具有适应性。近几十年来,国内外学者对关节柔性问题的研究取得了丰富成果。已开发具有部分柔性功能的关节,主要有伺服电机、液压缸和气缸驱动方式,且被广泛应用于各种机械和机器人中。但其体积较大关节偏“硬”,能实现的柔性功能程度有限。气动人工肌肉驱动因具有高度柔顺性,受到极大关注并已陆续研发出五种形式的人工肌肉。其中仅有McKibben型肌肉较为成功,在柔性机器人关节的驱动上已初步得到应用,但关节本体仍为刚性,具有综合柔性的关节尚待研究。在理论上,其大变形气动弹性体的力学特性还需要进一步深入探讨。本文从自主研制的气动人工肌肉着手,突破了传统主动关节的结构模式,提出了一种并联四肌肉组成的双向主动弯曲气动柔性关节。将关节本体需要的刚度分化到肌肉约束弹簧中,使驱动装置与关节本体复合为一体,具有本体柔性、运动柔性和驱动柔性。该关节能实现正屈、反伸、内收、外展和轴向移动,两个正交主方向弯曲能力强,具有较好的形状变化适应性。根据新型关节的特殊要求,创造性地提出了一种伸长型气动人工肌肉。采用约束弹簧和橡胶管组合的结构形式,使弹簧可根据关节的刚度要求调整参数,达到关节刚柔相宜的统一。在研究肌肉轴向膨胀的极限工作压力和约束稳定性基础上,建立了一种判断人工肌肉径向约束失稳的实验方法。发现了人工肌肉主动扭转变形规律,提出了一种SS型圆柱螺旋弹簧和双体人工肌肉的限扭转方案,经有限元分析表明SS型圆柱螺旋弹簧轴向变形和弯曲变形均属于线弹性。通过对人工肌肉力学性能的理论和实验研究,揭示了其相当于变参数柔性气缸的工作原理。针对人工肌肉大变形和非线性等问题,利用超弹性体变形能函数和经典弹性变形两种理论,研究了人工肌肉的静力学特性,给出了相应的数学公式。利用平动质量动能等效方法,建立了肌肉轴向变参数动力学模型,分析了其固有频率变化区间。为建立肌肉抗弯刚度的理论模型,对人工肌肉受载弯曲变形进行了分析,获得了理论计算公式。搭建了实验系统,采取光学投影等非接触式测量手段进行了肌肉的力学特性实验。在深入探索复合弹性体大变形特征的基础上,创建了新型柔性关节变参数静力学和动力学模型。利用组合弹性体变形叠加原理,建立了关节力学性能与人工肌肉特性的关系,关节的弯曲变形与气压的关系,得到了相应的数学公式,进行了实验验证。针对关节弯曲存在变形耦合、非线性和变参数等问题,通过轴向和弯曲质量动能等效方法,建立了关节变参数动力学模型,分析了关节主要固有频率变化规律。研究了柔性关节的驱动功能,关节接触点位置、气压、关节尺寸等参数对弯曲夹持力的影响,确定了关节五种主要变形状态的控制方法。基于双向弯曲柔性关节研发了一种具有全新结构和功能的五指柔性机械手。采取中指居中、四指相对布局,形成了以双拇指为主的抓取模式,保证了抓取的稳定性。采用了楔形盘为关节连接部件,结合独特的反伸功能,解决了机械手的灵活性和抓取物体范围的矛盾。为研究机械手位姿数学模型,将关节的非线性变形关系,以参数形式组合到齐次变换矩阵中,有效解决了弹性大变形非线性关节的坐标变换和位姿计算问题。具体推导了手指特征点在手掌坐标系中的位置,给出了手指四种模式位姿计算公式。利用Matlab软件,对手指的正屈、反伸、外展和内收功能进行了抓取仿真,得到了相应的轨迹和机械手抓取位姿图,并通过机械手抓取动作实验加以验证。本文对不同类型的手指夹持位置、气压和夹持力的关系进行了实验研究,并探讨了关节运动柔性和控制方式对夹持力的动态影响。通过对机械手抓取实物的实验分析,验证了其操作功能的实现效果。在深入分析机械手控制功能要求和特点的基础上,建立了由计算机、控制器和气压控制三部分组成的控制系统方案。针对柔性机械手四类12种抓取模式,研究了控制方法和气压控制系统结构,搭建了气动实验台。结合控制要求形成了电气控制系统结构方案,确定了机械手的具体控制方法和控制策略,给出了主要控制软件程序流程图。论文的研究工作为解决当前存在的关节柔性不足等问题,提供了一种新的解决方案。研究结果表明,所开发的主动弯曲关节,具有良好的综合柔性；利用该关节组合的柔性机械手,可完成人手的多数动作和功能。该关节可用于各类相关机械和机器人中,具有较高的研究价值和十分广阔的应用前景。更多还原

【Abstract】 Active joint is the key component of the biomimetic robot, and its structure characteristic, movements, mechanics, drive capability and control method determine the functions and application of the machine product. With the development of robotics, especially spread to fabricating industry, logistics, service and military affairs with unprecedented speed, people put forward higher request to the performance of the robot and propel a challenge for the structural flexibility, compliance, gentle drive and soft control. It is an urgent task to develop the biomimetic joints with integration flexibility, which can adapt to the change of environment and operational objectives.Many researchers have yielded important information on the problems of flexible joints. The joints in existence with portion flexibility are mainly driven by motor, hydraulic cylinder or functional materials, in which the motor driven and the hydraulic driven have widely used in machinery and robots, but its large bulk and rigidity greatly reduce the flexibility of joints. In order to improve the flexibility and compliance of the robot hand, many researchers have developed five types of PAM (Pneumatic Artificial Muscle). The McKibben muscle is more successful to drive the flexible joint of robot than the other artificial muscles. Yet this type of joint self is still rigid, the joint with integration flexibility is not formed so far, the mechanical properties of pneumatic elastic bodies with large deformation still is to be learned.In this thesis, a new type of flexible joint was carried out base on the elongation type of pneumatic artificial muscle we developed, the structure of joint break through the traditional pattern of active joint; four PAMs in parallel compose the bidirectional active flexible joint. The drive device and the joint itself compound as one which has good flexibility, the stiffness of the joint is distributed to the spring of the PAM. The joint can bend, anti-stretch, abduce, adduct and axial elongate. The bending capability in two orthogonal principal directions which let it has good adaptability to the changes in shape.In this thesis, we creatively put forward the elongation pneumatic artificial muscle. The structure of combined the constraint spring and the rubber tube, makes it easy to adjust the parameters of spring to change the stiffness of joint for suitability. Furthermore, we discussed the operating range of the artificial muscle and restrict stability; then put forward the experimental method to judge the instability destruction in radial of the artificial muscle. To solve the torsion of PAM, we put forward the SS type cylindrical spiral spring and artificial muscle with two bodies. It indicates that the axial and bending deformation of SS type cylindrical spiral spring is linear through the finite element analysis.This thesis has theoretical and experimental analysis on its mechanical properties; studied its work principle as the variation parameter cylinder. We have analysis on the static characteristics of PAM and establish the mathematical model using deformation energy function and the classical theory of elastic deformation to solve the large and non-linear deformation problem; established the variable dynamic model of PAM applying the equivalent method of translational kinetic energy and get the natural frequency interval; studied the axial and bending deformation of the new type of flexible joint. We also did the experiments on the PAM applying the non-contact measurement.In this thesis, we built the static and dynamic model with variable parameter of the joint based on the exploration of large deformation of compound elastic body; studied the relationship between the PAM and joint; discussed the relationship between the air pressure and the bending deformation; then get its mathematical model which is verified by the experiments. In addition, we established the variation parameter dynamic model of flexible joint, and get natural frequency regularity of joint. Furthermore, we investigated on the factors to influence to grasp force, such as the drive function and the contact position of joint, air pressure, the size of joint, etc.Then we decided the control system configuration of joint, where five mode of deformation are controlled.Based on the bidirectional bending active pneumatic flexible joints, we developed the five-fingered robot hand which has a brand new structure and function. The middle finger is in middle and the other four fingers are opposite to each other, which form the grasp mode with dual-thumb and ensure the stability of grasp. We adopted the wedge plate as the connection part, and combined the anti-stretch function of the hand to improve the flexibility and the grasp range of robot hand. We introduced the large deformation non-linear variables of flexible joints to the transformation matrix using the parametric translational coordinates; get the homogeneous transformation matrix of four patterns of the finger; get the trajectory and the pose of finger when it is bending, anti-stretch, abducent and adducent using matlab; and the experiments prove the validity of the theoretical model.We did experimental analysis on the relationship between grasp force as well as the grasp position and the air pressure; moreover, we discussed the influence of flexibility to grasp force. Then we did the experiments about robot hand to grasp the object, which verified the manipulation function of robot hand. We discussed on the control requirements and its characteristic, and then form the scheme of control system, which combined the computer, controller and pneumatic control system. We propose the control method to the four type grasp mode which including twelve moments of fingers; designed the pneumatic control system and built the pneumatic table; formed the electrical control system scheme. Then we determined the details of control method of fingers and robot hand as well as the flow chart of control program.The research of this thesis provided a new solution to solve the insufficiency of flexibility of joint as so far. The results show that the bidirectional active flexible bending joint we developed has good flexibility and compliance to meet the special requirements of the biomimetic joints; and the flexible robot hand composed by this joint can complete the action and function as human being, and it has high theoretical value and broad application prospects.更多还原