柔性机械臂动力学建模理论与实验研究进展

总结了国内外学者在柔性机械臂建模理论及其相关实验等方面的最新研究进展,系统地阐述了柔性机械臂的变形描述方法、关节动力学建模、柔性机械臂系统的动力学建模方法、臂杆的刚化和软化效应、柔性机械臂实验方法等方面的研究现状,提出了现阶段机械臂动力学理论与实验研究存在的问题与不足,预测了柔性机械臂动力学研究的主要方向和核心技术,详细分析了柔性机械臂最佳模态阶数选取、基于动力学特性的柔性机械臂系统参数优化、关节驱动规律的确定、柔性机械臂在高速运转下刚化与软化效应、柔性机械臂关节精细建模、空间柔性机械臂超低速运行时爬行现象等待解决的关键技术问题。     

谐波驱动柔性臂系统耦合动力学建模及辨识

为研究谐波驱动的柔性臂系统耦合动力学建模问题,分别进行了谐波驱动模型的参数辨识和柔性机械臂振动特性的耦合动力学模型辨识。通过阶跃电流激励和低匀速转动实验辨识出了关节的库伦摩擦力,在伪随机二进制信号的激励下,辨识得到了包含驱动系统转动惯量和黏性摩擦因数的驱动传递函数模型,将其与实际结构系统比较验证了此模型的准确性。理论分析了振动耦合力矩和柔性臂应变输出电压之间的线性关系,辨识得到了从电机转动角位移到柔性臂应变电压输出之间的传递函数,其输出在时域和频域上都与实际系统比较吻合,说明了建立的传递函数模型对于实际系统的适用性。综合两个辨识得到传递函数模型,实现了对谐波驱动的柔性机械臂系统的耦合动力学建模。     

六自由度并行机器人动力学模型及仿真

采用一种广泛应用于串行机器人动力学建模的方法──自然正交补（ＮＯＣ）法, 结合ｄ’Ａｌｅｍｂｅｒｔ虚功原理,推导出了不含约束力的六自由度并行机器人动力学模 型,并将它写成机器人动力学模型的一般形式,从而证明了在广义力对应的广义坐 标下,其惯性阵是对称、正定的。以此模型为基础,对一个典型运动进行了动力学仿 真,仿真结果验证了此模型的有效性。     

Optimal actuator sizing and end point deformation for mobile robotic manipulators with elastic joint based on load criteria

Application of a numerical method to determine the maximum dynamic load carrying capacity (DLCC) for a robotic manipulator carrying an automobile petrol tank with joint elasticity subject to accuracy and actuator constraints is described in this paper. The maximum DLCC which can be achieved by a manipulator during a given trajectory is limited by a number of factors. The most important of which are the dynamic specification of the manipulator, the actuator limitations, and the elasticity of the joints such as reducers and servo drive system. Initially, the kinematic equations for carrying the automobile petrol tank by the robotic arm with 6 degrees of freedom (DOF) were calculated. The mechanical modeling was achieved via software programming. Dynamic modeling of the flexible joints manipulator was done simply for the three major axes. A method for determination of the dynamic load capacity with specific reference to both accuracy and actuator constraints is explained. The results obtained indicate the importance of both constraints and which constraint is more critical for accuracy and tracking.     

2R欠驱动平面柔性机械臂的位置控制策略与试验研究

针对同时具有被动关节和柔性杆的欠驱动平面机械臂,提出一种简单易行的分段位置控制策略。以2R欠驱动平面柔性机械臂为研究对象,建立机械臂的假设模态动力学模型,分析系统的动力学耦合特性与可控性。通过被动关节处制动器的开闭切换,研究平面柔性机械臂的分段位置控制策略,采用PID方法分别设计各阶段主动、被动关节的控制算法。最后,基于自行开发的欠驱动平面机械臂的试验平台及实时控制系统,完成了2R欠驱动平面柔性机械臂位置控制的试验研究。仿真和试验结果表明,主动关节和被动关节在各阶段都能很好地跟踪目标值,进而实现机械臂的操作任务,验证了所提控制方法的可行性和有效性,以及欠驱动柔性机械臂动力学模型的正确性。     

平面3R操作臂动力学分析

操作臂是搬运机器人的关键部分,机器人作业主要依赖于操作臂的运动.针对采用D-H法建立运动学模型的平面三自由度旋转关节操作臂,在其运动规划基础上应用牛顿-欧拉法求解动力学方程.该方法建立在相邻连杆之间约束力和力矩的分析之上,具有方便直观、易于迭代求解的特点.在求出动力学方程后,将操作臂设计方案初始参数带入方程,验证了方程...     

柔索驱动并联机器人动力学建模与数值仿真

柔索驱动并联机器人采用柔索代替连杆作为驱动元件,并结合了并联机构和柔索驱动的优点。500 m口径大射电望远镜(Five-hundred meter aperture spherical radio telescope, FAST)粗调系统通过6根索长的协调变化使馈源舱作跟踪射电源的6自由度运动,其工作特点与并联机器人类似,因此可被看作柔索驱动并联机器人。基于此,根据FAST 5 m缩比试验模型,首先应用悬链线解析表达式推导出柔索两端固定时索端拉力与索长之间的关系,用于求解特定长度的驱动柔索对处于某一位姿的馈源舱的作用力。其次,对该舱索系统进行逆运动学分析,采用拉格朗日方程建立柔索驱动并联机器人的逆动力学模型。最后,针对FAST 5 m缩比模型的设计方案进行动力学仿真,数值结果表明该动力学建模是合理的。     

机器人柔性臂动力学建模的D-Holzer法

从改进柔性臂的模化原则出发,提出了多连杆复杂的柔性臂系统动力学建模的更为一般化的简单有效的D-Holzer法。用该法推导了两连杆柔性臂系统的动力学模型,并进行了动力学仿真。     

基于传感器的操作臂惯性参数在线识别神经网络模型

机器人惯性参数识别是机器人精确建模以及机器人控制和仿真的关键问题之一。机器人腕力传感器的接入将影响机器人系统的动力学特性 ,同时腕力传感器的输出也真实地反映了机器人的力作用和机器人末端的动力学特性。本文基于腕力传感器的输出信号 ,对在线识别机器人操作臂末端的惯性参数的方法进行了分析和研究 ,并建立了惯性参数在线识别的神经网络模型 ,网络学习后其权值即为辨识的惯性参数。     

垂直平面三杆柔性机械手动力学建模及仿真

为解决柔性机械手动力学建模常用的有限元等方法导致模型精度不高的问题,将柔性机械手视为连续整体,用矢量法建立了机械手的动力学模型。对比了矢量法和FEM法建立的动力学模型以及理想状态下机械手刚体动力学模型的仿真结果。对比结果表明,用矢量法建立的柔性机械手动力学模型是可行的,精度也较高。     

高速并联机械手的静动态特性预估与优化设计

借助ANSYS参数化设计语言（APDL），构造了一种2平动自由度的高速并联机械手的有限元模型，侧重研究了几种不同铰链的精确建模方法，以及机构处于不同位形时的有限元模型快速重构技术，分析了机械手的静、动态特性，在此基础上进行了结构优化设计，提高了机械手的静、动态特性，并成功应用于产品化样机。     

Tracking control of a three-wheeled omnidirectional mobile manipulator system with disturbance and friction

This paper proposes a tracking control method for a three-wheeled omnidirectional manipulator system (OMMS) with disturbance and friction. The OMMS is separated into two subsystems, a three-wheeled omnidirectional mobile platform (OMP) and a selective compliant articulated robot for assembly (SCARA) type of manipulator. Therefore, two controllers are designed to control the OMP and the manipulator system. Firstly, based on a kinematic modeling of the manipulator, a kinematic controller (KC), combined with an integral sliding mode controller (ISMC), is designed for the end-effector of the manipulator to track a desired trajectory with the desired angular velocity vector of links. Secondly, a differential sliding mode controller (DSMC) based on a dynamic modeling of the OMP with force external disturbances is proposed to obtain control inputs moving the OMP so that the manipulator tracks the desired posture without singularity. The system stability is proven using Lyapunov stability theory. The simulation and experimental results are presented to illustrate the effectiveness of the proposed controllers in the presence of disturbance and friction.     

水下大臂展机械手动力学建模与仿真分析

面向水下环境大范围精细作业需求,对水下大臂展机械手系统进行动力学建模和关节驱动力矩求解分析.首先,基于D-H理论对水下大臂展机械手进行正、逆运动学分析,求解各连杆速度与加速度;然后,构建水下大臂展机械手的动力学模型,使用莫里森公式和D-H理论完善动力学模型中的水动力项,采用拉格朗日法求解整机的净浮力、惯性力、离心力、科...     

双连杆柔性臂动力学建模与仿真分析

基于修正的固定界面子结构模态综合法———Craig-Bampton法,利用多体系统动力学仿真分析软件MSC.ADAMS与有限元分析软件MSC.NASTRAN完成对双连杆柔性机械臂动力学建模,进行了运动学仿真分析,并且与刚性臂运动相比较,对柔性机械臂末端运动振动信号进行了频谱分析。分析结果表明,这种方法在多柔体系统建模和分析中是精确和高效的。     

带闭链的五自由度工业机器人动力学解析模型

提出了一种建立带闭链的工业机器人动力学解析模型的方法。设想将闭式链的某一非主动关节的运动副断开 ,其运动关系用约束方程来代替 ,形成带有附加约束的等效系统 ,然后基于 Kane动力学方程 ,导出了显式形式的动力学方程。并将部分变量处理为符号量 ,其余变量处理为数字量 ,从而获得了动力学解析模型中各模型矩阵元素的数字 -符号表达式 ,并给出一实例进行说明     

Complete dynamic modeling and approximate state space equations of the flexible link manipulator

This work treats the problem of dynamic modeling and state space approximation for robotic manipulators with flexibility. Case studies are planar manipulators with a single flexible link together with clamped-free ends and tip mass conditions. In this paper, complete dynamic modeling of the flexible beam without premature linearization in the formulation of the dynamics equations is developed, whereby this model is capable of reproducing nonlinear dynamic effects, such as the beam stiffening due to the centrifugal and the Coriolis forces induced by rotation of the joints, giving it the capability to predict reliable dynamic behavior. On the other hand, in order to show the joint flexibility effects on the model dynamic behaviors, manipulator with structural and joint flexibility is considered. Thus, a reliable model for flexible beam is then presented. The model is founded on two basic assumptions: inextensibility of the neutral fiber and moderate rotations of the cross sections in order to account for the foreshortening of the beam due to bending. To achieve flexible manipulator control, the standard form of state space equations for a flexible manipulator system (flexible link and actuator) is very important. In this study, finite difference method for discretization of the dynamic equations is used and the state space equations of the flexible link with tip mass considering complete dynamic of the system are obtained. Simulation results indicated substantial improvements on dynamic behavior and it is shown that the joint flexibility has a considerable effect on the dynamic behavior of rotating flexible arm that should not be simply neglected. The effects of tip mass is proved to be increasing the elastic deformations?? amplitudes and increasing stability.     

基于ADAMS的锻造操作机动力学仿真及优化设计

基于三维实体建模软件Pro/E和动力学分析软件ADAMS,建立了某型5自由度锻造操作机的虚拟样机模型,并进行了动力学仿真分析及结构优化设计。该方法为锻造操作机的设计提供了一条有效途径。     

Comparative study of tracking control for a mobile manipulator: Nonholonomic and dynamic cases

This paper gives an in-depth treatment of the modeling and control of a mobile manipulator which consists of a robotic manipulator mounted upon a mobile robot. By neglecting slip of the platform's tires, nonholonomic constraints are introduced into the equations of motion. By considering wheel slip, the assumption of nonholonomic motion is violated. Nonholonomic and dynamic models of a mobile manipulator are developed and compared using the Lagrange-d'Alembert formulation and the Newton-Euler method, respectively. The dynamic model which considers wheel slip incorporates a nonlinear tire friction model. The tracking problem is investigated by using imput-output linearization for the nonholonomic model. For the dynamic model, a robust control method based on a matching condition is developed to eliminate the harmful effects of wheel slip, which acts as a disturbance to the system. Then, the effect of wheel slip on the tracking of commanded motion is identified via simulation. The effectiveness of the proposed control algorithm is demonstrated through computer simulation.     

A robust real time adaptive controller design for robot manipulator with eight-joints based on DSPs

In this paper we propose a new technique to the design and real-time control of an adaptive controller for robotic manipulator based on digital signal processors. The Texas Instruments DSPs (TMS320C80) chips are used in implementing real-time adaptive control algorithms to provide enhanced motion control performance for robotic manipulators. In the proposed scheme, adaptation laws are derived from model reference adaptive control principle based on the improved Lyapunov second method. The proposed adaptive controller consists of an adaptive feed-forward and feedback controller and time-varying auxiliary controller elements. The proposed control scheme is simple in structure, fast in computation, and suitable for realtime control. Moreover, this scheme does not require any accurate dynamic modeling, nor values of manipulator parameters and payload. Performance of the proposed adaptive controller is illustrated by simulation and experimental results for robot manipulator with eight joints at the joint space and cartesian space.     

并联机构机电耦合动力学计算

并联机构动力学模型是一个多输入、多输出、非线性、强耦合的复杂机电系统,目前还没有一个成熟的并联机构动力学建模和仿真计算方法.针对三自由度并联机构,建立了包括机械机构、伺服电机一体化的动力学模型.最后在设计好的运动平台轨迹下,计算了移动腿的位移、驱动电机的负载转距;分析了移动腿的误差.计算机仿真结果展示了控制器对机构位移和伺服电机转距良好的控制.