Grasp Planning and Visual Servoing for an Outdoors Aerial Dual Manipulator

This paper describes a system for grasping known objects with unmanned aerial vehicles (UAVs) provided with dual manipulators using an RGB-D camera. Aerial manipulation remains a very challenging task. This paper covers three principal aspects for this task: object detection and pose estimation, grasp planning, and in-flight grasp execution. First, an artificial neural network (ANN) is used to obtain clues regarding the object’s position. Next, an alignment algorithm is used to obtain the object’s sixdimensional (6D) pose, which is filtered with an extended Kalman filter. A three-dimensional (3D) model of the object is then used to estimate an arranged list of good grasps for the aerial manipulator. The results from the detection algorithm—that is, the object’s pose—are used to update the trajectories of the arms toward the object. If the target poses are not reachable due to the UAV’s oscillations, the algorithm switches to the next feasible grasp. This paper introduces the overall methodology, and provides the experimental results of both simulation and real experiments for each module, in addition to a video showing the results.

Manipulator tracking technology based on FSRUKF

Aiming at the shortcoming that the traditional industrial manipulator using off-line programming cannot change along with the change of external environment,the key technologies such as machine vision and manipulator control are studied,and a complete manipulator vision tracking system is designed.Firstly,Denavit-Hartenberg(D-H)parameters method is used to construct the model of the manipulator and analyze the forward and inverse kinematics equations of the manipulator.At the same time,a binocular camera is used to obtain the threedimensional position of the target.Secondly,in order to make the manipulator track the target more accurately,the fuzzy adaptive square root unscented Kalman filter(FSRUKF)is proposed to estimate the target state.Finally,the manipulator tracking system is built by using the position-based visual servo.The simulation experiments show that FSRUKF converges faster and with less error than the square root unscented Kalman filter(SRUKF),which meets the application requirements of the manipulator tracking system,and basically meets the application requirements of the manipulator tracking system in the practical experiments.

Compound Impedance Control of a Hydraulic Driven Parallel 3UPS/S Manipulator

The hydraulic parallel manipulator combines the high-power density of the hydraulic system and high rigidity of the parallel mechanism with excellent load-carrying capacity.However,the high-precision trajectory tracking control of the hydraulic parallel manipulator is challenged by the coupling dynamics of the parallel mechanism and the high nonlinearities of the hydraulic system.In this study,the trajectory control of a 3-DOF symmetric spherical parallel 3UPS/S manipulator is evaluated.Focusing on the highly coupling and nonlinear system dynamics,a compound impedance control method for a hydraulic driven parallel manipulator is proposed,which combines impedance control with the spatial motion characteristics of a parallel manipulator.The control strategy is divided into the inner and outer loops.The inner loop controls the impedance of the actuator in the joint space,and the outer loop controls the impedance of the entire platform in the task space to compensate the coupling of the actuators and improve the tracking accuracy of the moving platform.Compound impedance control does not require force or pressure sensors and is less dependent on modeling precision.The experimental results show that the compound impedance control effectively improves the tracking accuracy of the moving platform.This research proposes a compound impedance control strategy for a 3-DOF hydraulic parallel manipulator,which has high tracking precision with a simple and cheap system configuration.

Automatic Commissioning and Vibration Damping of Servo Drives with Flexible Load

Commissioning of P/PI-cascade controlled servo axes with flexible load can be quite time consuming, if the step response based setup procedures are applied for the velocity controller as indicated by the automation systems manufacturers. Based on the drive frequency response, suitable rules of thumb with optimum velocity control damping performance are derived in this contribution that turned out to be very efficient in several dozen machine tool servo axis applications of different industrial partners in Switzerland and southern Germany. Anyway, single feedback loop velocity control sometimes provides insufficient damping of structural vibrations, especially for high dynamic machine tools or robots. The axis performance can be improved significantly by state space control extensions that are meanwhile available for commercial machine tool control systems. This contribution explains the state space control extension application with effective commissioning rules of thumb for typical machine tool axes as well as robot joint drives. The achievable benefit is elucidated by exemplary machine tool axes.

基于FANUCServoGuide分析的机械手急停过程优化

运用FANUCServo Guide软件,测量机械手急停过程的伺服波形,分析机械手急停时的速度、扭矩曲线,并通过扭矩计算分析急停扭矩过大问题,最后给出了解决该问题的方法。

直驱型真空机械手运动规划与柔顺控制方法

半导体智能制造涉及的学科技术较多,其中运动规划和柔顺控制是半导体智能机器人技术研究的基础和重点。针对新松公司自主研发的MAG8真空机械手的特殊工作环境、晶圆易脱落等问题,完成了机械手的运动规划与柔顺控制研究。首先对其机械结构和运动方式进行了简要的介绍,可实现双臂的升降、旋转、伸缩动作,其次提出了Modify Denavit Hartenber法分析运动规划,建立了直驱型真空机械手上升轴和伸缩轴各连杆运动关系描述模型。再此,分析了直驱型真空机械手机械传动结构关系,采用牛顿-欧拉法计算各个关节力矩值解决了机械手柔顺控制问题,建立了用于分析各个关节力矩传递关系方程。经过对真空机械手进行仿真结果分析实验,验证了正、逆运动学过程的有效性。齐次变换矩阵可以实现MAG8运动部件以及大多数工业机器人的坐标变换,可用于MAG8的轨迹规划。对理论力矩值和这里所提出方法的实际力矩值进行对比,为进一步为柔顺控制的物理平台作业奠定了基础。

基于分层运动分解的飞行机械臂视觉伺服控制

飞行机械臂系统具有主动作业能力,通过搭载视觉传感器感知周围环境,系统的自主能力将进一步提高.然而,考虑到无人机的欠驱动和整个系统的非线性特性,飞行机械臂系统的视觉伺服控制仍然是一项具有挑战性的工作.本文在充分考虑机械臂对无人机的力/力矩作用后,提出了一种基于分层运动分解的飞行机械臂视觉伺服控制方案.首先,对飞行机械臂系统的运动学和动力学模型进行分析.然后,根据所得的相机运动学模型,通过基于图像的视觉伺服控制获得相机的期望速度,进而制定无人机和机械臂的速度分配策略.在考虑机械臂运动时对无人机产生的力/力矩影响,设计了底层的飞行控制器.最后,在与现有方法的仿真对比中可以看出,所提方法具有良好的控制性能,对图像特征点位置的不确定性及图像噪声也表现了较好的鲁棒性.

A hybrid visual servo control method for simultaneously controlling a nonholonomic mobile and a manipulator

Visual servo control rules that refer to the control methods of robot motion planning using image data acquired from the camera mounted on the robot have been widely applied to the motion control of robotic arms or mobile robots.The methods are usually classified as image-based visual servo,position-based visual servo,and hybrid visual servo(HVS)control rules.Mobile manipulation enhances the working range and flexibility of robotic arms.However,there is little work on applying visual servo control rules to the motion of the whole mobile manipulation robot.We propose an HVS motion control method for a mobile manipulation robot which combines a six-degreeof-freedom(6-DOF)robotic arm with a nonholonomic mobile base.Based on the kinematic differential equations of the mobile manipulation robot,the global Jacobian matrix of the whole robot is derived,and the HVS control equation is derived using the whole Jacobian matrix combined with position and visual image information.The distance between the gripper and target is calculated through the observation of the marker by a camera mounted on the gripper.The differences between the positions of the markers’feature points and the expected positions of them in the image coordinate system are also calculated.These differences are substituted into the control equation to obtain the speed control law of each degree of freedom of the mobile manipulation robot.To avoid the position error caused by observation,we also introduce the Kalman filter to correct the positions and orientations of the end of the manipulator.Finally,the proposed algorithm is validated on a mobile manipulation platform consisting of a Bulldog chassis,a UR5 robotic arm,and a ZED camera.

Natural Feature-based Visual Servoing for Grasping Target with an Aerial Manipulator

Aerial transportation and manipulation have attracted increasing attention in the unmanned aerial vehicle field,and visual servoing methodology is widely used to achieve the autonomous aerial grasping of a target object.However,the existing marker-based solutions pose a challenge to the practical application of target grasping owing to the difficulty in attaching markers on targets.To address this problem,this study proposes a novel image-based visual servoing controller based on natural features instead of artificial markers.The natural features are extracted from the target images and further processed to provide servoing feature points.A six degree-of-freedom(6-DoF)aerial manipulator system is proposed with differential kinematics deduced to achieve aerial grasping.Furthermore,a controller is designed when the target object is outside a manipulator's workspace by utilizing both the degrees-of-freedom of nnmanned aerial vehicle and manipulator joints.Thereafter,a weight matrix is used as basis to develop a multi-tasking visual servoing framework to integrate the controllers inside and outside the manipulator's workspace.Lastly,experimental results are provided to verify the effectiveness of the proposed approach.

电液伺服系统驱动机械臂的自适应反步法控制

在实际应用中,电液伺服系统存在非线性和参数不确定的特性,并且在作动器运动过程中可能受到外部随机干扰,会对电液伺服系统的控制造成较大影响。为了改善电液伺服系统在参数不确定性和未知扰动(即水力参数和外部负载)下的动态行为。首先,利用基于李亚普诺夫的反步法对电液伺服系统进行控制。然后,利用基于李亚普诺夫的参数自适应反步法对外部随机干扰和系统非线性进行抑制或补偿的控制方法进行了研究,比较了这两种控制策略的优缺点。表明了基于李亚普诺夫的的参数自适应反步法对于多个未知参数的情况下进行估计系统仍能保证具有的良好性能。

背后臂屈伸锻炼配合握肩拔伸手法联合中药熏洗治疗粘连性肩周炎的临床观察

目的探讨对粘连性肩周炎患者采取背后臂屈伸锻炼配合握肩拔伸手法联合中药熏洗治疗的临床效果。方法从南京中医药大学附属南京市中医院2019年1月—2021年9月收治的粘连性肩周炎患者中随机抽选出53例作为研究对象,评估患者治疗前,治疗1周、1个月和3个月后的视觉模拟量表(VAS)评分及采用Constant-Murley肩关节评分系统的肩周炎功能评分等指标的变化情况。结果从治疗1周后开始,患者的VAS评分越来越低。患者治疗后的Constant-Murley评分优于治疗前,差异有统计学意义(P<0.05)。结论对于粘连性肩周炎患者来说,臂屈伸锻炼配合握肩拔伸手法联合中药熏洗治疗,能减轻其关节的疼痛,改善其关节的活动度、肌力和日常活动能力,临床效果确切。

并联机械手集成电液伺服系统同步控制研究

为了提高并联机械手集成电液伺服驱动系统控制反应速度,降低末端执行器输出误差。介绍了一种具有三个独立控制的集成电液伺服驱动器,利用并联机械手的逆向运动学的表达式,推导出集成电液伺服驱动的平移并联机械手动力学模型。利用两个独立离散PI和PD控制器控制并联机械手输出力和位置,使驱动并联机械手三个液压缸输入电压控制信号保持同步。通过控制系统仿真软件对液压缸电压输入信号和末端执行器位置输出结果进行仿真。结果显示:采用同步控制方法,并联机械手集成电液伺服系统电压输入控制信号和末端执行器位置跟踪误差较小。采用同步控制方法,可以提高并联机械手集成电液伺服系统的自适应调节速度,提高末端执行器轨迹跟踪精度。

中医正骨手法联合筋伤膏治疗桡骨远端伸直型骨折的临床效果

目的研究桡骨远端伸直型骨折患者应用中医正骨手法联合筋伤膏对腕关节活动度的影响。方法选取2018年3月—2020年3月酒泉市中医院收治的100例桡骨远端伸直型骨折患者为研究对象,按挂号的先后顺序分为对照组和观察组,各50例。对照组采用西医复位治疗,观察组采用中医正骨手法联合筋伤膏治疗。比较两组临床疗效、临床指标变化、治疗前后视觉模拟评分量表(Visual Analog Scale,VAS)评分、腕关节功能改良加特兰德-韦利评分(Gartland-Werley,GW)及治疗前后腕关节活动度。结果观察组总有效率为100.00%高于对照组,差异有统计学意义(χ^(2)=5.982,P=0.014)。治疗后,观察组各项临床指标优于对照组,差异有统计学意义(P均<0.05)。治疗后,两组背伸度、掌屈度、旋后度明显升高,差异有统计学意义(P均<0.05),且观察组治疗后背伸度、掌屈度、旋后度更高,差异有统计学意义(P均<0.05)。治疗后,两组VAS、GW评分显著降低,差异有统计学意义(P均<0.05),且观察组治疗后VAS、GW评分更低,差异有统计学意义(P均<0.05)。结论桡骨远端伸直型骨折患者采用中医正骨手法联合筋伤膏治疗效果显著,可改善患者临床症状,促进骨折愈合,提高腕关节活动度。

基于数字化车间的连杆连续自动上料系统设计

基于数字化车间的技术特点,设计了一套连杆连续自动上料系统。该系统有效弥补了传统上料方式存在的不足,通过自动导向车(AGV)、桁架伺服机械手、机器视觉和协作机器人的协同配合,实现了连杆的自动输送、转运、视觉定位及自动抓取。

基于Σ-ΔADC的伺服系统电流环带宽延拓技术研究

研究了基于Σ-ΔADC的伺服系统电流环带宽延拓技术,旨在提高电流采样精度和电流环带宽。设计了一种与PWM中心对齐的平均电流同步采样方法,以减少采样过程中的噪声和延迟。通过优化PWM更新时序并采用SINC3滤波器的同步策略,实现了电流采样时刻与PWM周期的精准对齐,从而降低了电流环中的谐波干扰。提出了PI分离控制策略,分别为比例控制器和积分控制器配置不同滤波器,以兼顾系统的动态响应和稳态精度。实验结果表明,所提方法使相电流中的谐波幅值降低了80%,转矩反馈波动降低了64%,电流过零点的延迟时间从1.5 ms缩短至0.5 ms,电流跟踪的正弦度显著提升,有效提高了伺服系统电流环的动态性能和稳态精度。

基于全域优化的高速并联机械手控制器参数整定

提出一种新的定常PID参数整定方法。该方法综合考虑机电耦合效应、全域综合性能及随位姿实时变化的惯性负载,在操作空间内设计三条带有权重的运动轨迹,利用运动学正、逆解模型及刚体动力学逆解模型,直接建立以末端执行器操作空间的方均根误差最小为优化目标的整定方案,对伺服系统控制器的参数进行了整定。通过实例分析,给出使系统在整个工作空间内趋于最优的控制器参数的范围。该方法有效地解决了传统整定方法因其多目标函数相互制约而难以得到最优解的问题。试验验证该方法的正确性和有效性。

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.

PLC伺服控制在太阳能电池组件搬运机械手中的应用

针对太阳能电池组件生产过程中存在的工人劳动强度大和生产效率低等问题,设计一种采用真空吸盘结构的太阳能电池组件搬运机械手,搭建由PLC(可编程控制器)、伺服电机及驱动器构成的控制系统,并提出一种基于PLC的位置伺服控制方法。系统PLC程序采用模块化思想进行设计,并利用组态软件对触摸屏进行组态,通过串行端口建立PLC与触摸屏之间的通讯,实现PLC与触摸屏对搬运机械手的联合控制。应用结果表明,搬运机械手及其控制系统具有较好的交互性与灵活性且机械手自动运行过程稳定可靠达到了预期的设计目的。

基于PROFIBUS现场总线的装箱机械手控制系统

介绍了某醋厂灌装生产线装箱机械手控制系统,该系统由S7-300 PLC控制器、触摸屏、伺服放大器、同步伺服电机、机械手等组成。以S7-300 PLC作为主控制器,通过PROF IBU S-DP现场总线来控制伺服放大器以及现场执行设备,伺服放大器驱动伺服电机通过减速箱带动机械手进行精确的速度和位置控制。旋转变压器采样速度和位置从而构成速度、位置双闭环控制。抓、放瓶过程分成多段速度,在各段采用不同的P I调节参数,从而有效消除抖动。系统可以实现自动寻参考点,自学习、手动操作,自动操作4大功能。自安装调试成功以来,系统运行良好、性能可靠,极大地提高了劳动生产率。

颈椎病患者康复疗效评价研究

目的:通过研究正常人、颈椎病患者的疼痛程度、颈部功能和颈伸肌群力学指标在颈椎病康复过程中的变化情况,探讨颈椎病发生和康复的关键因素。方法:将63例颈椎病患者随机分为推拿组和牵引组,30例正常人对照组,观察疼痛评分、颈部功能评分,以及颈伸肌群峰力矩的变化情况。结果:颈椎病患者与正常组相比,疼痛程度明显升高(P<0.001),颈部残障指数明显减低(P<0.001),肌肉做功能力明显减低(P<0.001)。推拿手法与牵引治疗后,颈椎病患者的疼痛程度明显减低(P<0.001),颈部残障指数得到显著改善(P<0.001),肌力得到显著改善(P<0.05)。结论:颈椎周围肌群,尤其是颈伸肌肌力变化是颈椎病发生和发展的重要因素,作用于颈伸肌群的非手术疗法是颈椎病康复的有效手段。