【作者】 刘洋；

【导师】 李世其；

【作者基本信息】 华中科技大学 ， 机械设计及理论， 2009， 博士

【摘要】 传统机械臂的每个关节均由一个关节电机驱动,由于关节电机占机械臂关节比重较大,多个关节电机占据了机械臂悬臂部分的大部分重量,因此在伺服电机设计未有明显突破的情况下,采用新的机器人设计理论,对现有关节的冗余部分的功能进行重组,对机械臂关节结构进行重新设计,减少机械臂悬臂部分重量,是获得更紧凑结构、高负载自重比的一种方法。本文围绕轻型多关节机械臂的设计方法、新型传动结构、运动误差以及控制系统建模展开研究,主要内容如下：针对多关节机械臂的结构特点,总结前人的结构设计经验,研究了针对轻型机械臂的设计三个基本方法：单马达驱动技术、基于动态设计的功能置换方法,以及模块化广义锥形结构设计。研究了离合器耦合传动结构特点,设计了两种基于离合器耦合传动的关节结构。并采用离合器耦合传动关节设计了用于多关节机械臂的两自由度运动模块,给出了一种多关节机械臂的结构方案。建立了相邻关节正交的刚性机械臂运动学模型,分析了刚性机械臂末端运动轨迹；根据谐波减速器刚度随负载变化情况,建立了弹性关节机械臂的运动误差模型,分析了弹性机械臂末端运动轨迹误差；对关节处含偏心质量的弹性机械臂,建立了运动误差模型,分析了偏心质量对弹性机械臂末端运动轨迹误差的影响。根据机械臂关节结构特点,分析了影响机械臂运动性能的几个因素：关节主速、频率特性、工作空间等。仿真研究了机械臂末端在可达空间内的运动性能,并得到了用于控制系统参数选频的结构固有频率带。通过对离合器接合释放动作过程分析,建立了用于精确控制的离合器动力学模型。根据机械臂的负载和应用情况,建立了近似的离合器调速模型,研究了影响离合器输出速度的两个控制参数。采用离合器调速模型,建立了关节控制系统,并仿真分析了单关节控制系统和双关节控制系统位置控制过程。本文最后介绍了单马达驱动六自由度机械臂实验系统的结构和控制系统。通过两个连续轨迹控制(直线轨迹和半圆圆弧轨迹)实验和仿真,验证了机械臂各个关节结构的可行性、控制系统的有效性以及整个系统完成复杂轨迹的能力,并对实验结果进行了分析,讨论了误差补偿方法。更多还原

【Abstract】 The design of conventional manipulator is based on the style of one-joint-one-motor and every joint is driven by a motor. Compared to the mass of joint, the mass of the sevor motor is very big and the actuators often contribute a significant portion of the weight of manipulator outspreading. And it is a big challenge to design the little sevor motor now. As for the light manipulator design with big ratio between load and mass of joint, it is interesting to investigate the solution of compressing the components and using lesser motors to actuate more joints which can be used to decrease the mass of outspreading manipulator. This dissertation does some in-depth investigations on development of 6DOFs manipulator based on the methods of lighter manipulator design, the new mechanism of transforming, motion error model and clutch control system.Firstly, based on the structural features of the lighter manipulator and with reference to the conventional design, three methods of lighter manipulator design are proposed which are the techique of single-motor-driven, the principle of functions replacement based on dynamics, and modular design based on general bevel structrue. According to the three methods, the structural features of clutch coupling transforming mechanism are studied for joint design based on clutch working. Two joints designs based on clutch coupling transforming is introduced which axes are perpendicular to each other. The two joints are the component of a robot module with 2DoFs. A multi-joint manipulator is designed based on the robot module.Secondly, a motion model for rigid manipulator is built which joints axes are perpendicular to each other. The trajectory of the end of manipulator is studied by the kinematics of robot. The error model is built for flexible manipulator with flexible joint, and the motion error of flexible manipulator is studied under the same rules of joint motion with rigid manipulator. And the error model is built for the flexible manipulator with eccentric mass and the motion error for eccentric mass mounted in the joint is studied through comparison with the flexible manipulator with no eccentric mass in the joint.Thirdly, as for the joint structural features, manipulator performance for dynamic and kinematic is studied in the perspectives of main speed of joint, frequency characteristic and work space. The end of manipulator is simulated in the work space by software, and the frequencies of structure are obtained for control system. Forthly, with the analysis of clutch working process, a dynamic model is established for accurate control. According to the load of joint, the model of cluch with low speed and heavy load is established for the velocity modulated control system. Two parameters of control clutch system are studied. And a model for joint control is studied based on the simple clutch system. The single joint and double joints control system are simulated for position control in theory.Finally, it presents that the implementation of a new manipulator with six joints is driven by a DC motor. Two experiments and simulations which are line tracking and arc tracking are shown to verify the experimental system. And the methods for error compenstation are proposed in the structure and control system design.更多还原