仿水黾机器人划水腿刚柔耦合动力学建模与仿真研究

仿水黾机器人一般采用轻型材料制作并且是在较高速度下运行,构件的弹性变形将直接影响机器人系统的运动特性.本文采用假设模态法来描述划水腿的变形,在Lagrange方程的基础上建立仿水黾机器人驱动机构划水腿的刚柔耦合动力学模型,数值仿真曲线描绘出划水腿的柔性变形对末端轨迹的影响.该研究为该机器人今后进行主动控制,获得更快的运动速度,准确运行轨迹路线奠定基础.     

一种新型TBM清渣机器人机构设计与试验

隧道底部积渣清理是TBM施工中钢拱架立拱前的必备环节。随着对支护质量、施工效率、安全性要求越来越高,传统的人工清渣越来越难以满足施工要求,清渣机器人是破解这一难题的重要手段。首先,分析隧道底部积渣分布情况与环境结构特点,进行新型机器人机构设计;其次,基于Denavit-Hartenberg（D-H）参数法建立其连杆坐标系,进行正逆运动学计算,给出了末端位姿矩阵表达式和逆运动学解析解,并进行工作空间计算和分析,结果表明机器人能够实现3830mm的作业深度和±45°的作业范围;基于拉格朗日方程建立其动力学模型,采用五次多项式进行关节空间轨迹规划,并将规划的位移、速度、加速度代入动力学模型,获得关节驱动力矩仿真曲线,为摆动缸、直线油缸等驱动件的选型提供依据;然后,以单关节位置控制为例,进行积分分离PID控制器设计,与传统PID相比,将超调量降低18.7%,解决位置误差累积引起的关节抖动问题;最后搭建了隧道底部积渣清理试验平台,并进行隧道底部积渣清理实验,结果表明,该清渣机器人作业周期为53s,可作为敞开式TBM施工过程隧道底部积渣清理的有效解决方案。     

机器人电液伺服系统建模的仿真方法

利用拉格朗日方程导出关节型机器人电液伺服系统的动力学方程。在一定的条件下,对此方程进行了简化和线性化,得到了系统的实用数学模型。在实验装置上对系统进行实时仿真,用频率法对模型的参数进行估计,其结果验证了这种数学模型的可信程度。     

平面五杆并联机器人动力学分析

用拉格朗日法推导出平面五杆并联机器人的动力学模型,得出驱动力矩的表达式.通过对平面五杆并联机器人模型的分析,得出了平面五杆并联机器人的主动关节等效惯量、耦合惯量和驱动力矩的变化规律.结果表明,对于给定的运动规律,机构的位形对系统的主动关节等效惯量、耦合惯量和驱动力矩的影响较大.     

串联旋转关节空间机器人的动力学仿真系统

空间机器人由于基座可以自由运动,增加了自由度,其运动学和动力学模型比地面固定基座机器人要复杂得多,而且低轨航天器受重力梯度影响较大。首先推导了空间机器人的运动学方程,并采用拉格朗日方程建立了正动力学模型,然后基于牛顿-欧拉法推导了空间机器人的耦合动力学方程,给出了动力学非线性项的数值计算方法,还推导了空间机器人在轨运动时的重力梯度力矩。最后,针对一类串联旋转关节的空间机器人,采用模块化设计的思想建立了动力学仿真模型,利用所建仿真模型对空间机器人的操作任务进行数值仿真,分析了重力梯度力矩的影响,提出了减小这些影响的建议。     

欠驱动异构式下肢康复机器人动力学分析及参数优化

针对现有外骨骼机器人人机自由度不匹配和关节对中性差的问题,提出欠驱动下肢康复机器人. 欠驱动机器人只有4个直线驱动,驱动的直线运动通过推杆和人机连接机构转化为人下肢在矢状面内的屈伸运动,带动人体进行步态康复训练. 建立机器人系统的人机耦合模型,进行模型的动力学分析,对人机耦合模型中影响动力学结果的参数进行分析,建立驱动力与肢体推动力之间的关系模型,并以推力系数最大为目标进行参数分析与优化,得到最佳的结构参数. 根据优化后的结构参数搭建康复机器人实验系统,对髋、膝关节驱动力与角度进行对比. 实验结果表明最大髋关节角度误差为2.9°,最大膝关节角度误差为6.4°,最大误差均约为9%,验证了动力学模型和参数优化结果的正确性.     

连杆侧无传感器下机器人柔性关节系统的零力控制

针对机器人直接示教应用场景,提出机器人柔性关节系统在连杆侧无传感器下的零力控制方法. 引入动态LuGre摩擦模型进行关节摩擦力矩估计,采用2段四次多项式建立柔性关节系统刚度模型,基于广义动量观测关节力矩. 该方法利用刚度逆模型以及关节力矩估算谐波减速器扭转位移,结合谐波减速器运动传递特性估计连杆侧角度并计算重力矩,利用连杆动力学方程估计接触力矩. 构建期望的电机驱动力矩（包含估计的重力矩、摩擦力矩与接触力矩）,通过对该期望电机驱动力矩的跟踪实现零力控制. 在搭建的机器人柔性关节系统实验平台上进行实验. 实验结果表明,完成相同的拖动示教过程时,该方法所需要的接触力矩约为1.8 N·m. 基于重力矩与摩擦力矩补偿的零力控制方法需要接触力矩约为3.4 N·m. 功率级脱离示教所需要的接触力矩约为14 N·m,验证了所提方法的实际效果.     

自由漂浮空间机器人力矩最优轨迹规划算法

针对自由漂浮空间机器人的轨迹规划问题,提出一种基于粒子群优化算法的机械臂关节角驱动力矩最优轨迹规划算法.首先通过对自由漂浮空间机器人系统的动力学方程进行分析,给出了以机械臂关节角驱动力矩为目标函数的轨迹最优控制算法,并采用高阶多项式插值方法逼近机械臂关节角轨迹,结合粒子群优化算法对机械臂关节角轨迹进行优化求解.数值仿真表明,规划出的关节角轨迹平滑连续,在完成自由漂浮空间机器人姿态调整任务的同时,机械臂关节角驱动力矩降至最低.     

模块化协作机器人运动特性分析及动力学仿真研究

针对UR10模块化协作机器人的构型特点,采用D-H坐标变换法建立其运动学坐标系,采用逆变换法对机器人进行逆运动学求解,求得各个关节转角。运用拉格朗日法对UR机器人进行动力学分析,利用ADAMS多体动力学仿真软件对其进行动力学仿真。结果证明,该模块化协作机器人具有良好的静态平衡性能、运动稳定性和动态响应特性。     

沿架空地线行驶的自主巡检机器人及应用

介绍了一种沿架空地线行驶的输电线路自主巡检机器人系统,包括自主巡检机器人本体、地面基站、巡检后台管理系统,以及地线无阻挡道路结构等.开发的新型防震锤线夹、组合悬垂线夹和跨越耐张杆塔头柔性过桥等结构,使得机器人可以无阻挡地通过防震锤、直线杆塔和耐张杆塔等而无需跨越障碍物.着重介绍了自主巡检机器人的如下关键技术:移动机器人机构、自主移动导航、电源及其管理系统和机器人本体的系统集成,给出了自主巡检机器人的一个典型实例.通过不同环境的运行试验,表明提出的巡检机器人系统的正确性和实用性.     

Anti-Dead-Zone Integral Sliding Control and Active Vibration Suppression of a Free-floating Space Robot with Elastic Base and Flexible Links

Under the conditions of joint torque output dead-zone and external disturbance, the trajectory tracking and vibration suppression for a free-floating space robot (FFSR) system with elastic base and flexible links were discussed. First, using the Lagrange equation of the second kind, the dynamic model of the system was derived. Second, utilizing singular perturbation theory, a slow subsystem describing the rigid motion and a fast subsystem corresponding to flexible vibration were obtained. For the slow subsystem, when the width of dead-zone is uncertain, a dead-zone pre-compensator was designed to eliminate the impact of joint torque output dead-zone, and an integral sliding mode neural network control was proposed. The integral sliding mode term can reduce the steady state error. For the fast subsystem, an optimal linear quadratic regulator(LQR) controller was adopted to damp out the vibration of the flexible links and elastic base simultaneously. Finally, computer simulations show the effectiveness of the compound control method.     

Dynamic modeling and analysis of 3-RRS parallel manipulator with flexible links

The dynamic modeling and solution of the 3-(R)RS spatial parallel manipulators with flexible links were investigated. Firstly, a new model of spatial flexible beam element was proposed, and the dynamic equations of elements and branches of the parallel manipulator were derived. Secondly, according to the kinematic coupling relationship between the moving platform and flexible links, the kinematic constraints of the flexible parallel manipulator were proposed. Thirdly, using the kinematic constraint equations and dynamic model of the moving platform, the overall system dynamic equations of the parallel manipulator were obtained by assembling the dynamic equations of branches. Furthermore, a few commonly used effective solutions of second-order differential equation system with variable coefficients were discussed. Newmark numerical method was used to solve the dynamic equations of the flexible parallel manipulator. Finally, the dynamic responses of the moving platform and driving torques of the 3-RRS parallel mechanism with flexible links were analyzed through numerical simulation. The results provide important information for analysis of dynamic performance, dynamics optimization design, dynamic simulation and control of the 3-RRS flexible parallel manipulator.     

多运动状态下移动机器人的动力学建模与分析

通过对关节履带式移动机器人越障过程的运动分析,基于履带车辆行驶力学分析及牛顿-欧拉方程,建立了机器人复合越障运动状态的动力学模型.并以车体的运动为控制目标,分析计算了车体、摆臂的运动变化以及驱动力矩的变化.仿真图形验证了机器人具有良好的运动稳定性,为机器人越障过程的控制奠定了基础.     

Resonance Suppression Strategy for Humanoid Robot Arm

To address the problem of resonance in the control of a robot arm, a resonance suppression strategy is proposed for a single-joint humanoid robot arm based on the proportional-resonant(PR) controller. First, an arm joint model of the humanoid robot is established. Then the influence of resonance frequency on the performance of the control system with the robot arm is analyzed. The voltage fluctuation of the drive motor caused by the changes in arm motion is recognized as the disturbance of the current loop. The PR controller has the characteristic of disturbance rejection at a specific frequency. The output fluctuation of the driving system caused by the change of arm motion state at the resonance frequency is suppressed. Therefore the output current of the inverter will not be affected by the vibration of the arm at the resonance frequency. Finally, the control system is verified by MATLAB/Simulink simulation. The simulation results demonstrate that the control strategy for the humanoid robot arm based on the PR controller can suppress the resonance of the arm effectively, improving the dynamic performance and system stability.     

含拐点的柔顺机构动力学建模及分析

为分析含拐点的大变形柔性梁的动态响应,建立含拐点的柔顺杆的动力学模型,基于拉格朗日方程推导其动力学方程组,在MATLAB软件中求解出其转角随时间变化的特性曲线,并与ADAMS软件仿真所得角位移曲线进行比较.研究表明:含拐点柔顺机构的拐点关节依靠各杆间的动力学耦合运动,拐点关节的转角变化很大,这体现了含拐点的柔顺机构动力学模型与不含拐点的柔顺机构动力学模型的区别,柔顺机构动力学模型能精确地反映柔顺机构的运动和变形.     

Extremum response surface method of reliability analysis on two-link flexible robot manipulator

In order to present a new method for analyzing the reliability of a two-link flexible robot manipulator, Lagrange dynamics differential equations of the two-link flexible robot manipulator were established by using the integrated modal method and the multi-body system dynamics method. By using the Monte Carlo method, the random sample values of the dynamic parameters were obtained and Lagrange dynamics differential equations were solved for each random sample value which revealed their displacement, speed and acceleration. On this basis, dynamic stresses and deformations were obtained. By taking the maximum values of the stresses and the deformations as output responses and the random sample values of dynamic parameters as input quantities, extremum response surface functions were established. A number of random samples were then obtained by using the Monte Carlo method and then the reliability was analyzed by using the extremum response surface method. The results show that the extremum response surface method is an efficient and fast reliability analysis method with high-accuracy for the two-link flexible robot manipulator.     

Dynamic Path Following Control of a Ground Ackerman Steering Robot to Avoid a Collision

A novel method is proposed to dynamically control the path following of a ground Ackerman steering robot to avoid a collision. The method consists of collision prediction module, collision avoidance module and global path following module. The elliptic repulsive potential field method (ER-PFM) and the enhanced vector polar histogram method (VPH +) based on the Ackerman steering model are proposed to predict the collision in a dynamic environment. The collision avoidance is realized by the proposed cost function and speed control law. The global path following process is achieved by pure pursuit. Experiments show that the robot can fulfill the dynamic path following task safely and efficiently using the proposed method.     

压电柔性机械臂的轨迹跟踪控制

提出一种利用压电材料对柔性机械臂进行末端轨迹跟踪控制的方法．利用假设模态法,采用压电作动器和传感器同位配置,根据Lagrange方程建立了单连杆柔性机械臂的动力学模型;针对柔性机械臂的非最小相位特点,以刚性旋转关节的转角为控制输出、以压电作动器抑制柔性机械臂的末端振动,基于Lyapunov函数,采用PD(proportional-differential)控制策略实现了对柔性机械臂进行末端轨迹跟踪控制．仿真结果表明,压电作动器很好地抑制了柔性机械臂末端的振动,末端的轨迹跟踪由关节驱动和压电作动共同完成,PD控制算法简单,易于工程实现．     

空间柔性机器人动力学分析的快速积分算法

以空间柔性机器人为研究对象,分析了机器人柔性多体系统动力学建模过程,研究了根据广义动力学方法所建立的大型微分-代数方程的快速数值积分算法.本文采用Lagrange方法研究了空间柔性机器人的动力学模型,通过判断系统中铰的类型(主动关节和被动关节),建立机器人系统的微分-代数动力学方程,最后采用线性多步积分算法对建立的大型微分-代数方程进行高效率求解. 仿真算例的结果表明,本文研究的线性多步积分算法对求解大型微分-代数方程速度快,效率高,为空间机器人实时动力学仿真打下坚实的基础.     

一款微小型球形机器人的动力学分析

利用拉格朗日方程等力学手段,分析了一款微小型球形机器人滚动和转动的运动特点,以及跳跃运动的起跳条件.分析该类机器人的进动形式的运动形态,建立了整合运动的通用动力学模型,实现了机器人沿任意曲线运动.对机器人进行了虚拟样机仿真,实验验证了上述分析的正确性.该研究为机器人非线性控制打下了基础.