The inertial characteristics of dynamic robot modelsCaracteristiques inertielles des modeles dynamiques robotiques

Robot dynamics are embedded in the mathematical foundations of classical mechanics to introduce novel physical interpretations and structural characteristics of the Lagrangian dynamic robot model. Within this framework, the centrality of the inertial matrix emerges. The physical significance of the inertial coefficients is further illuminated by the introduction of the coefficient of coupling of robotic manipulators. The properties of the inertial matrix follow directly from the kinematic and dynamic parameters of the robot. These properties translate into the characteristics of the centrifugal, Coriolis and gravitational components of the dynamic robot model. The novel approach reinforces the need to integrate the mechanical and controller designs of robotic manipulators. The conceptual framework leads to design guidelines for simplifying and reducing the nonlinear kinematic and dynamic coupling of robot dynamics. The development of the paper is applied to illustrate the properties and structural characteristics of industrial robots.     

基于解析模型法的机器人动力学建模自动生成软件系统

基于改进的机器人动力学解析（数字-符号）模型算法,研制出用于机器人动力学自动建模的计算机辅助生成软件。在计算机上自动生成机器人的动力学模型元素与运动方程,并产生动力学模型的实时代码。采用的解析模型算法改进了动力模型多项式结构矩阵的优化算法,还简化了代码输出程序,大大减少了中间变量与赋值语句。提高了运算速度及导致最少的浮点乘/加数。该软件还带有图形接口,用于仿真时具有动画显示功能。     

ANALYTICAL MODEL ALGORITHM FOR DYNAMICS OF ROBOTIC MANIPULATORS

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可重构机器人单元组合的自同构研究

可重构机器人利用单元组合结构,可以提高环境适应性,改善机器人的使用性能,本文首先提出了一种新的可重构机器人单元结构模型,然后针对可重构机器人拓扑构形中所存在自同构问题,根据单元组合拓扑构形的邻接矩阵,提出了拓扑结点的关联属性及其关联度码的概念,在此基础上,提出了单元组合自同构的列举算法,以及同一拓扑构形特征下所有非同构单元组合状态的计算方法。最后对一拓扑构形实例进行了计算,计算结果表明,本文提出的自同构算法简便有效,使用灵活,可用于可重构机器人的单元组合结构设计。     

NEW APPROACHES FOR COMPUTING DYNAMIC LOAD-CARRYING CAPACITY OF MULTIPLE COOPERATING ROBOTIC MANIPULATORS

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机械式挖掘机建模及动力学分析

利用机器人理论和方法对机械式挖掘机进行建模和动力学研究.首先根据WS-005机械式挖掘机的结构及运动特性,采用机器人建模方法,建立了挖掘机模型,求出其运动学方程;然后结合工程机械作业特点,探讨了挖掘轨迹规划的方法,并给出挖掘过程中的规划结果;最后运用拉格朗日法求出其动力学方程,并分析了挖掘过程中所受的外力,进而给出该过程中动力学结果,为下一步机械式挖掘机的智能控制提供了重要依据.     

Design, modelling and errors measurement of wheeled mobile robots

This paper presents the mechanical design process of an omni-directional mobile robot. In addition, the kinematics equations of the final design are derived, and the inverse Jacobian matrix of the robot is presented. The dynamic equations of motion for the final design are derived in a symbolic form, assuming that no slip occurs on the wheel in the spin direction. In order to validate the kinematics and dynamic equation, we carried out consequences of simulation using two pieces of software, Maple and Working Model. Finally, the mobile robot is moved in given trajectories and the systematic errors of the robot are determined. To overcome the problems, a new method was introduced in which the robot was programmed to move in the direction of each wheel shaft.     

绳索驱动式变刚度关节柔顺控制与力补偿方法研究

机器人柔顺运动有助于提高机器人交互运动时的安全性与稳定性,越来越受到人们的重视。针对一种绳索驱动式具有主被动柔顺性的柔性机器人关节,提出一种适用于绳索驱动式变刚度关节的刚度与位置解耦控制方式,实现了关节位置控制的同时,又实现了关节柔顺性的统一。利用雅可比矩阵和模型间静力学关系,得到关节刚度模型,并通过优化方法对变刚度装置的力学模型和刚度模型构成的非线性方程组求解,实现变刚度关节刚度与位置的非线性解耦。在解耦控制基础上提出一种力矩观测方法,实现了关节力矩补偿,增强了关节位置控制能力;建立了绳索驱动式变刚度关节样机和控制系统,并通过仿真和实验分析的方式验证了所提柔顺控制方式的可行性和有效性。     

Kinematics and dynamics analysis of a quadruped walking robot with parallel leg mechanism

It is desired to require a walking robot for the elderly and the disabled to have large capacity,high stiffness,stability,etc.However,the existing walking robots cannot achieve these requirements because of the weight-payload ratio and simple function.Therefore,Improvement of enhancing capacity and functions of the walking robot is an important research issue.According to walking requirements and combining modularization and reconfigurable ideas,a quadruped/biped reconfigurable walking robot with parallel leg mechanism is proposed.The proposed robot can be used for both a biped and a quadruped walking robot.The kinematics and performance analysis of a 3-UPU parallel mechanism which is the basic leg mechanism of a quadruped walking robot are conducted and the structural parameters are optimized.The results show that performance of the walking robot is optimal when the circumradius R,r of the upper and lower platform of leg mechanism are 161.7 mm,57.7 mm,respectively.Based on the optimal results,the kinematics and dynamics of the quadruped walking robot in the static walking mode are derived with the application of parallel mechanism and influence coefficient theory,and the optimal coordination distribution of the dynamic load for the quadruped walking robot with over-determinate inputs is analyzed,which solves dynamic load coupling caused by the branches’ constraint of the robot in the walk process.Besides laying a theoretical foundation for development of the prototype,the kinematics and dynamics studies on the quadruped walking robot also boost the theoretical research of the quadruped walking and the practical applications of parallel mechanism.     

基于微分几何的欠驱动机器人动力学建模和控制

应用位形流形最小嵌入模型,对带有二阶非完整约束的欠驱动机器人动力学建模和控制进行研究。采用位形流形最小嵌入模型,简化了动力学方程,为欠驱动机器人动力学建模和控制的进一步研究奠定了基础。首先用一个齐次线性方程组表示被动关节的存在,给出基于嵌入模型的动力学方程解的结构。通过引入计算转矩控制法,给出另一个和主动关节及控制输入有关的齐次线性方程组,分析控制输入和这两个方程组解之间的关系,得到一个与控制输入及这两个方程组的解相关的欠定线性方程组,求解该欠定线性方程组,得到欠驱动机器人改进的动力学方程,进而可以运用全驱动机器人控制法来实现最小嵌入模型的控制,解决了由全驱动机器人控制法实现欠驱动机器人关节空间控制的问题。最后以平面二杆欠驱动机器人为例,验证了所得理论的可行性和有效性。     

Validation of dynamic torque response of an electrorheological (ER) clutch

It is now well established that using actuators, which have faster speeds of response than d.c. servomotors, can solve the positional errors of the robot arms. One of the possible robotic actuators can be an electro-rheological (ER) clutch. To justify this objective, the authors measured the output torque response of a co-axial ER clutch. However, due to the dynamic inefficiency of a torque transducer, the measured torque response is inaccurate for analytical studies. Therefore, this measured torque is signal processed by using the transfer functions of this torque sensor and a filter to yield the ER torque response. The validity of this ER torque is investigated by comparing the numerical errors between the measured torque and its inverse torque response. From the torque error analysis, it is concluded that the ER clutch can be an actuator to improve the positioning accuracies of the robot arms.     

基于广义几何误差模型的微机器人精度分析

提出了一个用于微机器人精度分析的通用方法,该方法以广义几何误差的形式描述各种误差源对机器人本体产生的影响,通过任两座标系间的向后微分关系,利用运动学方程以及并联机构的环路特性,建立了微机器人的广义几何误差模型。基于此模型,对工作空间中的位姿误差进行了仿真分析,验证了该法的有效性。此方法虽然是针对微机器人,但可推广应用到一般并联机器人的误差建模和精度分析。     

A total torque index for dynamic performance evaluation of a radial symmetric six-legged robot

This article focuses on the dynamic index and performance of a radial symmetric six-legged robot. At first the structure of the robot is described in brief and its inverse kinematics is presented. Then the dynamic model is formulated as based on the Lagrange equations. A novel index of total torque is proposed by considering the posture of the supporting legs. The new index can be used to optimize the leg’s structure and operation for consuming minimum power and avoiding unstable postures of the robot. A characterization of the proposed six-legged robot is obtained by a parametric analysis of robot performance through simulation using the presented dynamic model. Main influences are outlined as well as the usefulness of the proposed performance index.     

一种简单的行走助力机器人的设计与仿真

行走助力机器人是近年来兴起一新的研究领域,它属于特种机器人的范畴。行走助力机器人可以增强人体下肢的力量,可以为老年人、残疾人、士兵和消防员等提供增强行走能力的服务。在本篇论文中,首先是在分析人体行走特定的基础上设计了一款简单的行走助力机器人,并通过运动学逆求解得到了各个关节的角位移计算方程。然后采用微分变换法来求取雅可比矩阵来对速度运动学进行分析。最后采用Pro/E和ADAMS对机器人进行了动力学仿真,并对仿真中出现的问题和测量所得曲线进行了分析。     

A study on tracking error based on mechatronics model of a 5-DOF hybrid spray-painting robot

Industrial robots suffer from difficulties in predicting and guaranteeing tracking performance due to the complex dynamic behavior and inaccurate mechatronics model. This study investigates the tracking error and motion accuracy improvement based on a mechatronics model of a 5-degree of freedom hybrid spray-painting robot. The dynamic model of the robot is derived by using Lagrange equation, and an identification method is presented to identify the torque coefficient and joint friction synchronously. An accurate mechatronics model is established after the theoretical dynamic modeling and friction identification. The tracking error generation mechanism of the robot control system is studied, and its analytical equation is derived on the basis of a transfer function. A multichannel feedforward controller is synthesized to reduce the tracking error from different sources. The effectiveness of the proposed method in improving tracking accuracy is verified by physical experiments.

     

可重构磁耦合水下推进器的磁场分析及性能评估

在保证微小型水下机器人运动灵活的同时,降低矢量推进器机械复杂性,改善其防水密封问题,设计了一款可重构磁耦 合的水下矢量推进器。 基于磁耦合非接触式动力传输,解决了驱动电机与螺旋桨之间的防水问题;与此同时,采用重构机构在 两自由度内改变螺旋桨位姿,实现了可重构矢量推进水下机器人的目的。 在建立磁耦合磁场模型的基础上,通过 ANSYS Maxwell 磁场仿真与搭建的磁转矩测量装置,验证了磁场建模的正确性并分析了重构机构对磁耦合动力传输磁转矩的影响。 在 此基础上,进一步搭建了螺旋桨水下测力装置,评估了转速与推力以及不同重构角下最大矢量推力的变化情况。 结果表明,推 进器能够在[-15°,15°]两自由度可重构角范围内稳定地输出矢量推力。     

Constraint-plane-based synthesis and topology variation of a class of metamorphic parallel mechanisms

This paper investigates various topologies and mobility of a class of metamorphic parallel mechanisms synthesized with reconfigurable rTPS limbs. Based on the reconfigurable Hooke (rT) joint, the rTPS limb has two phases which result in parallel mechanisms having ability of mobility change. While in one phase the limb has no constraint to the platform, in the other it constrains the spherical joint center to lie on a plane which is used to demonstrate different topologies of the nrTPS metamorphic parallel mechanisms by investigating various relations (parallel or intersecting) among the n constraint planes (n = 2,3,..,6). Geometric constraint equations of the platform rotation matrix and translation vector are set up based on the point-plane constraint, which reveals mobility and redundant geometric conditions of the mechanism topologies. By altering the limbs into the non-constraint phase without constraint plane, new mechanism phases are deduced with mobility change based on each mechanism topology.     

ONLINE MODEL AND ACTUATOR FAULT TOLERANT CONTROL FOR AUTONOMOUS MOBILE ROBOT

A novel fault-tolerant adaptive control methodology against the actuator faults is proposed. The actuator effectiveness factors (AEFs) are introduced to denote the healthy of actuator, and the unscented Kalman filter (UKF) is employed for online estimation of both the motion states and the AEFs of mobile robot. A square root version of the UKF is introduced to improve efficiency and numerical stability. Using the information from the UKF, the reconfigurable controller is designed automatically based on an enhancement inverse dynamic control (IDC) methodology. The experiment on a 3-DOF omni-directional mobile robot is performed, and the effectiveness of the proposed method is demonstrated.