Contact detumbling toward a nutating target through deformable effectors and prescribed performance controller

Detumbling operation toward a rotating target with nutation is meaningful for debris removal but challenging. In this study, a deformable end-effector is first designed based on the requirements for contacting the nutating target. A dual-arm robotic system installed with the deformable end-effectors is modeled and the movement of the end-tips is analyzed. The complex operation of the contact toward a nutating target places strict requirements on control accuracy and controller robustness. Thus, an improvement of the tracking error transformation is proposed and an adaptive sliding mode controller with prescribed performance is designed to guarantee the fast and precise motion of the effector during the contact detumbling.Finally, by employing the proposed effector and the controller,numerical simulations are carried out to verify the effectiveness and efficiency of the contact detumbling toward a nutating target.

智能双臂无影灯系统的协同运动控制

在当前手术照明系统中,手动调节光照位置以消除遮挡物阴影的操作会导致外科医生的注意力分散,且存在污染手术区域无菌环境的可能性,为解决这一问题,提出了一种智能双臂无影灯系统解决方案。采用串联型五自由度双机械臂构建照明系统并建立了D-H数学模型,对机械臂的正、逆运动学进行了求解;针对交叉聚焦照射和主从补光照射两种临床光照场景,提出了相应的双臂协同运动约束机制和运动规划方法;最后,在MATLAB环境中对双臂无影灯系统的协同运动控制算法进行了仿真分析。研究结果表明:双臂协同运动控制算法可行且效果良好,双臂末端和各关节的运动轨迹均柔顺、无突变,智能双臂无影灯系统能够很好地满足手术中的光照调节要求。

Scheduling algorithm of dual-armed cluster tools with residency time and reentrant constraints

To solve the scheduling problem of dual-armed cluster tools for wafer fabrications with residency time and reentrant constraints,a heuristic scheduling algorithm was developed.Firstly,on the basis of formulating scheduling problems domain of dual-armed cluster tools,a non-integer programming model was set up with a minimizing objective function of the makespan.Combining characteristics of residency time and reentrant constraints,a scheduling algorithm of searching the optimal operation path of dual-armed transport module was presented under many kinds of robotic scheduling paths for dual-armed cluster tools.Finally,the experiments were designed to evaluate the proposed algorithm.The results show that the proposed algorithm is feasible and efficient for obtaining an optimal scheduling solution of dual-armed cluster tools with residency time and reentrant constraints.

The Fuzzy Neural Network Control Scheme With H∞ Tracking Characteristic of Space Robot System With Dual-arm After Capturing a Spin Spacecraft

In this paper,the dynamic evolution for a dualarm space robot capturing a spacecraft is studied,the impact effect and the coordinated stabilization control problem for postimpact closed chain system are discussed.At first,the pre-impact dynamic equations of open chain dual-arm space robot are established by Lagrangian approach,and the dynamic equations of a spacecraft are obtained by Newton-Euler method.Based on the results,with the process of integral and simplify,the response of the dual-arm space robot impacted by the spacecraft is analyzed by momentum conservation law and force transfer law.The closed chain system is formed in the post-impact phase.Closed chain constraint equations are obtained by the constraints of closed-loop geometry and kinematics.With the closed chain constraint equations,the composite system dynamic equations are derived.Secondly,the recurrent fuzzy neural network control scheme is designed for calm motion of unstable closed chain system with uncertain system parameter.In order to overcome the effects of uncertain system inertial parameters,the recurrent fuzzy neural network is used to approximate the unknown part,the control method with H∞tracking characteristic.According to the Lyapunov theory,the global stability is demonstrated.Meanwhile,the weighted minimum-norm theory is introduced to distribute torques guarantee that cooperative operation between manipulators.At last,numerical examples simulate the response of the collision,and the efficiency of the control scheme is verified by the simulation results.

Singular perturbation composite control of a free-floating flexible dual-arm space robot

The Free-floating Flexible Dual-arm Space Robot is a highly nonlinear and coupled dynamics system. In this paper, the dynamic model is derived of a Free-floating Flexible Dual-arm Space Robot holding a rigid payload. Furthermore, according to the singular perturbation method, the system is separated into a slow subsystem representing rigid body motion of the robot and a fast subsystem representing the flexible link dynamics. For the slow subsystem, based on the second method of Lyapunov, using simple quantitative bounds on the model uncertainties, a robust tracking controller design is used during the trajectory tracking phase. The optimal control method is designed in the fast subsystem to guarantee the exponential stability. With the combination of the two above, the system can track the expected trajectory accurately, even though with uncertainty in model parameters, and its flexible vibration gets suppressed, too. Finally, some simulation tests have been conducted to verify the effectiveness of the proposed methods.

Adaptive neural network control for coordinated motion of a dual-arm space robot system with uncertain parameters

Control of coordinated motion between the base attitude and the arm joints of a free-floating dual-arm space robot with uncertain parameters is discussed. By combining the relation of system linear momentum conversation with the Lagrangian approach, the dynamic equation of a robot is established. Based on the above results, the free-floating dual-arm space robot system is modeled with RBF neural networks, the GL matrix and its product operator. With all uncertain inertial system parameters, an adaptive RBF neural network control scheme is developed for coordinated motion between the base attitude and the arm joints. The proposed scheme does not need linear parameterization of the dynamic equation of the system and any accurate prior-knowledge of the actual inertial parameters. Also it does not need to train the neural network offline so that it would present real-time and online applications. A planar free-floating dual-arm space robot is simulated to show feasibility of the proposed scheme.

基于旋量理论6自由度双臂作业系统正运动学与工作空间分析

机械臂的轨迹规划和控制的前提,是进行机械臂的正运动学分析。目前,主要的分析方法为D-H参数法。提出了一种比D-H法更快捷、更简单、利于计算的旋量理论方法。通过指数积公式对双臂作业系统进行运动学建模并建立正运动学方程。运用Simpack软件对双臂作业系统进行仿真分析,通过仿真的结果和正运动学方程所求解的结果对比,验证了通过旋量理论建立的正运动学模型的正确性。利用Matlab软件进行工作空间的分析,通过工作空间云图的对比,得到双臂作业系统的工作空间。

Compliance motion control of the hydraulic dual-arm manipulator with adaptive mass estimation of unknown object

Given the limited operating ability of a single robotic arm,dual-arm collaborative operations have become increasingly prominent.Compared with the electrically driven dual-arm manipulator,due to the unknown heavy load,difficulty in measuring contact forces,and control complexity during the closed-chain object transportation task,the hydraulic dual-arm manipulator(HDM)faces more difficulty in accurately tracking the desired motion trajectory,which may cause object deformation or even breakage.To overcome this problem,a compliance motion control method is proposed in this paper for the HDM.The mass parameter of the unknown object is obtained by using an adaptive method based on velocity error.Due to the difficulty in obtaining the actual internal force of the object,the pressure signal from the pressure sensor of the hydraulic system is used to estimate the contact force at the end-effector(EE)of two hydraulic manipulators(HMs).Further,the estimated contact force is used to calculate the actual internal force on the object.Then,a compliance motion controller is designed for HDM closed-chain collaboration.The position and internal force errors of the object are reduced by the feedback of the position,velocity,and internal force errors of the object to achieve the effect of the compliance motion of the HDM,i.e.,to reduce the motion error and internal force of the object.The required velocity and force at the EE of the two HMs,including the position and internal force errors of the object,are inputted into separate position controllers.In addition,the position controllers of the two individual HMs are designed to enable precise motion control by using the virtual decomposition control method.Finally,comparative experiments are carried out on a hydraulic dual-arm test bench.The proposed method is validated by the experimental results,which demonstrate improved object position accuracy and reduced internal force.

MEMS陀螺双通道数字接口系统设计

针对现有的MEMS陀螺接口系统只能对一个陀螺进行测控导致标定测控效率低下的问题,提出了一种新型的可同时对两个陀螺进行测控的MEMS陀螺双通道接口系统架构,并设计了一套与之对应的MEMS陀螺双通道测控电路,包括前端模拟电路、后端数字系统和人机交互终端。通过设计的人机交互系统对整个系统的全部功能进行了测试,其中扫频、锁相、稳幅、线性度和零偏稳定性等功能均能正常运行,在实际使用测试中相较于单通道接口系统测控效率提升到2倍以上。

移动双臂机械手系统协调操作的视觉伺服技术

本文利用双目泛倾斜变焦摄像机(pan-tilt-zoom,PTZ)像机,实现移动双臂机械手系统的视觉伺服协调操作,重点研究室内复杂环境和光照变化情况下目标物体的检测、识别和定位问题.首先,提出了色调、饱和度、亮度颜色模型(hue-saturation-value,HSV)空间下图像分割的改进算法,通过阈值更新和外接矩形改善分割结果,提高检测算法对环境光照变化的适应性;然后,基于Hu不变矩,利用物体形状特征,对检测得到的物体加以识别:在此基础上,利用摄像机投影矩阵,计算目标物体的空间坐标,实现其定位测量:最后,在实验室平台上,通过模拟双臂倒水操作,验证提出的图像处理和分析算法以及视觉伺服协调操作方案的有效性.实验结果表明移动双臂机械手系统能够成功完成倒水动作的协调操作.

双机械臂协调控制综述

双机械臂协调控制是实现机器人仿人控制的重要环节,实现协调控制需要依据完成任务的特点建模以及研究新的控制算法支持.本文对目前双机械臂建模方法、协调控制算法的研究进展进行了综述.建模是在刚性建模的基础上加入不同约束完成;控制算法涉及主从协调控制,自适应控制和视觉伺服控制以及其它智能控制算法.针对柔性操作对象,为实现控制目标,考虑增加对象的振动、机械臂运动产生的额外作用力、夹持对象的反作用力,介绍了控制机械臂运动的对应算法.还介绍了在人机协作领域目前的最新研究成果,并且分析控制方法目前存在的问题,对研究工作的发展趋势进行了展望.

双臂空间机器人系统运动规划的双向逼近方法

基于双向逼近方法,讨论了载体位置与姿态均不受控制的双臂空间机器人系统的运动规划问题。该方法以系统动量和动量矩守恒关系为基础,建立了控制系统设计所需系统状态方程;并通过对系统状态方程应用双向逼近方法,获得了机械臂关节角的控制输入方程,从而达到对载体姿态及机械臂关节角的双重控制效果。该方法的优点是减少了载体姿态控制燃料的消耗,有效地延长了空间机器人系统的使用寿命。系统数值仿真证明了该方法的有效性。

双臂空间机器人惯性空间轨迹跟踪的鲁棒混合自适应控制

讨论了载体位置与姿态均不受控情况下,漂浮基双臂空间机器人系统跟踪惯性空间轨迹的控制问题。为了克服空间机器人系统控制方程关于惯性参数的非线性性质,空间机器人被表示为欠驱动系统,保持了系统动力学方程关于惯性参数的线性关系;对系统的运动学分析表明,联系机械臂末端抓手运动线速度与机器人关节铰速度的Jacobi关系也可以通过增广向量的处理,得到保持惯性参数线性关系的增广广义Jacobi关系。基于以上结果,针对系统参数不确定的情况下,设计了自由漂浮双臂空间机器人跟踪惯性空间期望轨迹的鲁棒混合自适应控制方案。由于在上述系统运动学、动力学分析中耦合了系统动量守恒关系,所提出的控制方案具有不需要测量、反馈机器人载体位置、移动速度、加速度的优点;同时,由于上述控制方案仅在参考速度、加速度的计算中采取了参数调节方式,而在控制部分对不确定参数采用了保持鲁棒性的方法,有效地减少了计算量,有助于缓解空间机器人机载计算机运算能力有限的矛盾。通过对一个平面双臂空间机器人系统的数值仿真,验证了算法的有效性。

基于CAN总线结构的服务机器人模块化双臂系统构建

针对商品化工业机器人手臂系统封闭、开放性差的问题,采用机器人可重构模块来构建机器人的双臂系统。在分析机器人手臂构成特点的基础上,进行了手臂模块的选型,完成了由模块化关节组成的服务机器人双臂硬件平台的搭建;通过分析手臂功能模块化的特点,设计了手臂的分布式控制系统方案,并通过实验验证了双臂软硬件系统构建的正确性及稳定性。

双臂空间机器人关节运动的一种增广自适应控制方法

讨论了载体位置、姿态均不受控制情况下,具有未知参数的自由漂浮双臂空间机器人系统的自适应控制问题.由于此类机器人系统具有结合系统动量及动量矩守恒关系得到完全能控形式的系统动力学方程,以及系统惯性参数不符合惯常的线性函数关系的特点,因而地面机器人的控制方法在此难以直接推广应用.为了克服上述难点,仅将系统动量守恒关系耦合到系统动力学方程当中,而不耦合系统动量矩守恒关系,结果得到一组欠驱动形式的系统动力学方程.该系统动力学方程的优点是关于一组组合惯性参数能保持惯常的线性函数关系.以此为基础,并借助增广变量法,针对双臂空间机器人末端爪手所持载荷参数未知的情况,设计了关节空间轨迹跟踪的自适应控制方案.该控制方案的显著优点为,不需要测量、反馈双臂空间机器人漂浮基的位置、移动速度和移动加速度.系统的数值仿真,证实了方法的有效性.

激光双定位系统在C型臂X线机中的应用

阐述了通过在C型臂X线机的球管侧和增强器侧分别安装2个激光器,利用激光形成的"十字交叉"进行预先定位的激光双定位系统方案,通过等效模型测量了定位误差并分析了产生误差的原因及缩小误差的方法。

双臂空间机器人姿态与关节协调运动的自适应控制、鲁棒控制

讨论了载体位置不受控制情况下的双臂空间机器人姿态和关节协调运动的自适应与鲁棒控制问题。利用拉格朗日方法导出了双臂空间机器人欠驱动形式的系统动力学方程;在该方程的基础上,基于增广变量法(恰当地扩展系统的控制输入和输出),成功地克服了完全能控形式的空间机器人系统动力学方程关于惯性参数呈非线性函数关系的难点;针对双臂空间机器人两末端抓手所持载荷参数未知与不确定两种情况,分别设计了载体姿态与机械臂各关节协调运动的自适应控制和鲁棒控制方案。系统数值仿真表明,两种控制方案均可有效消除空间机器人系统惯性参数未知和不确定的影响,控制双臂空间机器人的载体姿态与机械臂各关节准确地完成期望的运动。

漂浮基双臂空间机器人惯性空间轨迹跟踪的拟增广自适应控制

讨论了载体位置、姿态均不受控制的漂浮基双臂空间机器人系统的自适应控制问题。为了克服空间机器人系统动量及动量矩守恒关系的引入,使得系统动力学方程关于系统惯性参数呈非线性关系,给控制系统设计带来的困难,漂浮基双臂空间机器人系统的动力学方程被表示为欠驱动形式。其优点在于,相应的控制系统状态方程保持了惯常的关于系统惯性参数的线性性质。以此为基础,并借助于增广变量法,通过恰当地虚拟扩展系统的控制输入与输出,成功地克服了漂浮基双臂空间机器人系统自适应控制方案设计的难点,针对双臂空间机器人两个末端抓手持有载荷参数均未知的情况,设计了漂浮基双臂空间机器人两个末端抓手惯性空间轨迹跟踪的拟增广自适应控制方案。通过系统数值仿真,证实了上述控制方法的有效性。

双臂空间机器人系统末端惯性空间轨迹的反馈跟踪控制

本文讨论了载体位置不受控制的双臂空间机器人系统的载体姿态与机械臂末端抓手协调运动的控制问题。结合系统的动量守恒关系对双臂空间机器人系统的运动学、动力学作了分析,推导出了系统的载体姿态与机械臂末端抓手协调运动的增广广义Jacobi关系。并以此为基础,给出在载体位置不受控制的情况下,惯性坐标系内双臂空间机器人系统的载体姿态与机械臂末端抓手协调运动的反馈跟踪控制规律。研究结果表明,在系统动力学模型及参数较精确确定的情况下,本文提出的控制方案能够有效地控制双臂空间机器人机械臂的末端抓手与载体姿态准确地完成指定的运动,而不需对其载体的位置进行主动控制。仿真计算结果证实了方法的有效性。

双臂机器人动力学建模与伺服系统控制

针对双臂机器人的手臂运动控制问题,研究了其动力学建模与伺服系统控制算法。首先,对其双臂机械结构进行了分析,总结了各个关节对机器人末端位姿的影响,并且简化了动力学方程更利于实现。其次针对简化后的模型参数采用最小二乘法辨识,最后通过仿真和系统实验,验证动力学计算结果的正确性。再次由机器人动力学和电机动力学建立关节转矩模型进行关节转矩力控制;最后讨论了交流永磁同步电机的建模和控制问题。经过验证简化后的模型一方面等效于直流电机便于设计控制器,另一方面可用于机器人关节转矩控制。