Designing and Optimization of an Off-line Programming System for Robotic Belt Grinding Process

Off-line programming （OLP） system becomes one of the most important programming modules for the robotic belt grinding process, however there lacks research on increasing the grinding dexterous space depending on the OLP system. A new type of grinding robot and a novel robotic belt grinding workcell are forwarded, and their features are briefly introduced. An open and object-oriented off-line programming system is developed for this robotic belt grinding system. The parameters of the trimmed surface are read from the initial graphics exchange specification （IGES） file of the CAD model of the workpiece. The deBoor-Cox basis function is used to sample the grinding target with local contact frame on the workpiece. The numerical formula of inverse kinematics is set up based on Newton＇s iterative procedure, to calculate the grinding robot configurations corresponding to the grinding targets. After the grinding path is obtained, the OLP system turns to be more effective than the teach-by-showing system. In order to improve the grinding workspace, an optimization algorithm for dynamic tool frame is proposed and performed on the special robotic belt grinding system. The initial tool frame and the interval of neighboring tool frames are defined as the preparation of the algorithm. An optimized tool local frame can be selected to grind the complex surface for a maximum dexterity index of the robot. Under the optimization algorithm, a simulation of grinding a vane is included and comparison of grinding workspace is done before and after the tool frame optimization. By the algorithm, the grinding workspace can be enlarged. Moreover the dynamic tool frame can be considered to add one degree-of-freedom to the grinding kinematical chain, which provides the theoretical support for the improvement of robotic dexterity for the complex surface grinding.

CONTROLLING ROBOT MANIPULATORS BY DYNAMIC PROGRAMMING

A certain number of considerations should be taken into account in the dynamic control of robot manipulators as highly complex non-linear systems.In this article,we provide a detailed presentation of the mechanical and electrical impli- cations of robots equipped with DC motor actuators.This model takes into account all non-linear aspects of the system.Then,we develop computational algorithms for optimal control based on dynamic programming.The robot's trajectory must be predefined,but performance criteria and constraints applying to the system are not limited and we may adapt them freely to the robot and the task being studied.As an example,a manipulator arm with 3 degrees of freedom is analyzed.

Study on path planning and compensation of off-line programming for thick walled curve welding

Thick walled curve welding are usually joined by multi-layer and multi-pass welding, which quality and efficiency could be improved by off-line programming of robot welding. However, the precision of off-line programming welding path was decreased due to the deviation between the off-line planned welding path and the actual welding path. A path planning algorithm and a path compensation algorithm of multi-layer and multi-pass curve welding seam for off-line programming of robot welding are developed in this paper. Experimental results show that the robot off-line programming improves the welding efftcieney and precision for thick walled curve welding seam.

Off-line simulation of robot welding of radar pedestal

A study of the interference simulation based on robot welding of the radar pedestal was carried out by using the KUKA Sim Pro simulation software and off-line program technology. Compared with the actual robot welding process, it was found that the trajectory of the simulated robot welding process in line with that recorded in the actual welding process, and the actual limit and interference appeared at the same place as the simulation process. There was no interference phenomenon on the outside weld-seam; on the internal weld-seam, especially on the weld-joint of support plate connected to the cylinder, a phenomenon of interference appeared. It was helpful to use the simulation method to guide the actual robot welding so as to protect robot from impacting and reduce the weld defects.

Programming Methods for 6-Degree of Freedom Robot Teaching

In this paper, programming method for industrial robot teaching and composing of robot language system is described. Through the RBT - 6T/S01S as an example,the program and instruction function of the robot language are summarized. The compo- sition of RBT - 6T/S01S robot system is studied,and the programming of robot clamping and assembly parts teaching is made.

Compliant landing of a trotting quadruped robot based on hybrid motion/force robust control

A compliant landing strategy for a trotting quadruped robot on unknown rough terrains based on contact force control is presented. Firstly, in order to lower the disturbance caused by the landing impact force, a landing phase is added between the swing phase and the stance phase, where the desired contact force is set as a small positive constant. Secondly, the joint torque optimization of the stance legs is formulated as a quadratic programming(QP) problem subject to equality and inequality/bound constraints. And a primal-dual dynamical system solver based on linear variational inequalities(LVI) is applied to solve this QP problem. Furthermore, based on the optimization results, a hybrid motion/force robust controller is designed to realize the tracking of the contact force, while the constraints of the stance feet landing angles are fulfilled simultaneously. Finally, the experiments are performed to validate the proposed methods.

Robotic Knee Tracking Control to Mimic the Intact Human Knee Profile Based on Actor-Critic Reinforcement Learning

We address a state-of-the-art reinforcement learning(RL)control approach to automatically configure robotic pros-thesis impedance parameters to enable end-to-end,continuous locomotion intended for transfemoral amputee subjects.Specifically,our actor-critic based RL provides tracking control of a robotic knee prosthesis to mimic the intact knee profile.This is a significant advance from our previous RL based automatic tuning of prosthesis control parameters which have centered on regulation control with a designer prescribed robotic knee profile as the target.In addition to presenting the tracking control algorithm based on direct heuristic dynamic programming(dHDP),we provide a control performance guarantee including the case of constrained inputs.We show that our proposed tracking control possesses several important properties,such as weight convergence of the learning networks,Bellman(sub)optimality of the cost-to-go value function and control input,and practical stability of the human-robot system.We further provide a systematic simulation of the proposed tracking control using a realistic human-robot system simulator,the OpenSim,to emulate how the dHDP enables level ground walking,walking on different terrains and at different paces.These results show that our proposed dHDP based tracking control is not only theoretically suitable,but also practically useful.

基于多人零和博弈的模块化机器人系统近似最优控制

提出一种基于多人零和博弈的模块化机器人(Modular Robot Manipulators, MRMs)系统近似最优控制方法。建立了具有交联耦合(Interconnected Dynamic Couplings, IDC)的模块化机器人系统动力学模型。将机器人系统的控制律和IDC效应作为零和博弈的参与者,MRM系统的最优跟踪控制问题转化为多人零和博弈问题。根据自适应动态规划(Adaptive Dynamic Programming, ADP)算法,通过建立评判神经网络求解哈密顿-雅克比-埃塞克斯(Hamilton-Jacobi-Issacs, HJI)方程,推导出最优控制律。基于李雅普诺夫定理,证明了闭环机器人系统是渐近稳定的,最后通过实验验证了所提控制方法的有效性。

Off-Line Programming of a Robot for Laser Re-Manufacturing

Off-line programming provides an essential link for CAD/CAM. This paper introduced the principle of developing off-line programming system for laser re-manufacturing. Task and information flow of off-line programming for laser re-manufacturing robot was analyzed and the software structure of off-line programming based on commercial CAD software was constructed. The off-line programming system developed in this study includes 3-D solid model design, direct slicing for obtaining path data, graphical simulation of the robot and its workcell, kinematic model of the robot, motion planning, and creation of the control program for manufacturing process. The CAD software was used to design models of robot, workpiece, coaxial nozzle, and workspace. Through the application programming interface provided by the CAD software, the VC++ and ATL were chosen to develop such modules as direct slicing for obtaining path data, path planning, process specification, and control program automatic generation. The FANUC Roboguide software was used to realize graphical simulation. By direct slicing, the position and orientation data of robot end-effector was determined. The results show that the proposed system can be applied in laser re-manufacturing robot for manufacturing operations.

基于STM32的舞蹈机器人舵机控制器设计

机器人舞蹈动作的实现离不开机器人对各个关节处的舵机精确控制,而舵机控制器是控制舵机精确转动的关键,实现舞蹈机器人动作的流畅、自然的保证。基于STM32F103RCT6单片机,开发了24路舵机控制器,实现了PC端对舞蹈机器人的实时在线调试,舞蹈机器人舞蹈动作的编辑、下载及离线运行,舞蹈机器人对应角度的转动,提高了多路舵机的控制精度。系统设计包括舵机控制器模块、上位机对单片机下载程序、上位机软件。与PID舵机控制器的对比实验结果证明,所设计的STM32F103RCT6单片机舵机控制器的稳态误差和最大超调量都为0,表明所设计的舵机控制器系统超调量和静态误差都很小,系统具有很好的稳态和动态性能,控制精度高,响应速度快,满足竞赛对舞蹈机器人的需求。

基于ROBONOVA2平台的舞蹈机器人设计与实现

基于ROBONOVA2平台推出了一款舞蹈机器人,通过Robobasic平台和图形化界面对机器人进行开发。结合了军旅文化主题,基于ROBONOVA2的舞蹈机器人设计并实现了一套舞蹈动作,并通过舵机控制,较好的提高了机器人的动作协调度与人机交互性。

基于故障观测器的机器人多关节手臂最优容错控制

针对机器人多关节手臂容易出现卡死、饱和及损伤等故障影响控制精度的问题,利用设计的故障观测器提出了一种最优容错控制律。首先根据机器人多关节手臂末端的空间位置与各关节转动角度的关系,建立了机器人多关节手臂的故障模型;然后定义了多关节手臂的转角和接触力的跟踪误差,并设计了故障观测器,通过引入径向基函数(Radial Basis Function,RBF)神经网络估计出模型参数;最后根据动态规划的思想,建立了综合位置/接触力跟踪误差和故障的机器人多关节手臂性能指标矩阵,并设计了包含Hamiltonian方程的容错控制律,利用RBF神经网络求解出最优的性能指标,从而得到最优的容错控制律。仿真结果表明,设计的最优容错控制律能够克服各类故障带来的影响,故障估计的最大误差仅为0.09 N·m,位置跟踪的最大误差仅为0.14 cm,接触力控制的最大误差仅为0.18 N,验证了设计方法的可行性。六自由度多关节手臂测试结果表明,在8个空间坐标上定位的最大误差仅为0.17 cm,接触力的最大误差仅为0.22 N,从而验证了设计的最优容错控制律具有优越的工程实用性。

面向未知空间的模块化机器人最优位置-力控制研究

针对模块化机器人系统与外界未知环境交互的控制任务,提出一种基于自适应动态规划的位置-力控制。首先,考虑模块化机器人系统受未知环境约束,对未知环境约束空间进行分析,并设计自适应估计算法近似未知约束参数向量,从而得到未知外部约束力转化为模块化机器人所受的近似约束力矩,设计融合位置和末端接触力跟踪误差的多指标性能指标函数,结合自适应动态规划思想和策略迭代算法,求解哈密尔顿方程,从而实现面向未知空间的模块化机器人最优位置-力控制。

多机型底盘涂装线机器人自动喷涂程序输入方法应用

根据喷涂程序快速输入的需要,设计了机器人喷涂控制系统。主要介绍了该系统的硬件组成及具体工作流程,详细阐述了利用触摸屏实现喷涂程序的手动输入的模式,以及建立该系统与MES系统的信息通道从而实现喷涂程序自动输入的过程。

基于EMPC的四足机器人控制方法研究

为了提高四足机器人的运动性能和弥补模型预测控制在线计算量大的不足,提出了基于显式模型预测控制(EMPC)理论的四足机器人控制方法。基于动力学和运动学理论建立四足机器人的状态空间模型,并确定目标函数和约束条件;利用EMPC理论,得到显式控制律实现四足机器人的控制。仿真结果表明,所提出的EMPC控制方法减少了在线计算时间,实现了四足机器人足端力控制。

Study on motion simulation of arc welding robot based on UG

The motion simulation of arc welding robot is the basis of the system of robot off-line programming, and it has been one of the important research directions. The UGNX 4. 0 is adopted to establish 3D simulating model of MOTOMAN-HP6 arc welding robot. The kinematic model under link-pole coordinate system is established by the second development function offered by UG/OPEN API and the method of programming using VC ＋＋ 6. 0. The methods of founding model and operational procedures are introduced, which provides a good basis for off-line programming technique under Unigraphies condition.

基于Robot Studio的ABB工业机器人码垛工作站教学设计

通过Robot Studio环境中搭建虚拟码垛工作站,分析ABB工业机器人离线编程环境中Smart组件的应用、I/O信号的创建和连接、程序调试和仿真验证等知识点,提高对于离线编程的综合应用能力。

Developing of robot flexible processing system for shipbuilding profile steel

A robot flexible processing system of shipbuilding profile steel was developed. The system consists of computer integrated control and robot. An off line programming robot was used for marking and cutting of shipbuilding profile steel. In the system the deformation and position error of profile steel can be detected by precise sensors, and figure position coordinate error resulted from profile steel deformation can be compensated by modifying traveling track of robotic arm online. The practical operation results show that the system performance can meet the needs of profile steel processing.

Kinematic Study on Motoman HP6 Arc Welding Robot Based on Unigraphics

The links of Motoman HP6 arc welding robot are considered as an open kinematic chain which consists of a series of rotational joints through concatenation. One end of the open chain is fixed to the base or the earth, and the other end which is free fastens the end executor to complete various duties. Each link of this arc welding robot has four kinds of Denavit-Hartenberg parameters: common normal length between two adjacent links, angle of two adjacent joints, distance between the crossing of common normal length and two joints axes, and angle of two adjacent links. The displacement relation between each link of the Motoman HP6 arc welding robot is introduced, and the kinematic positive-going solution and the kinematic passive-going solution are calculated.

面向机器人柑橘采摘的控制系统设计与试验

面向柑橘采摘,构建以上位机、RealSense Camera R200深度相机、VS-6556垂直多关节工业用机械臂、三指柔性手爪等组成的采摘机器人硬件平台。以Windows10为开发环境,采用librealsense相机软件开发工具包、OpenCV计算机视觉库、TensorFlow-GPU和Keras深度学习框架、ORIN2机械臂控制软件开发工具包、Arduino IDE函数库以及SerialPort串口通信软件开发工具包等,研究基于深度相机、机械臂二次开发的采摘控制系统设计,包括视觉识别定位、手爪动作控制、机械臂运动控制以及采摘控制等模块的程序设计。采摘控制系统柑橘定位试验和柑橘采摘试验的测试结果显示,在实验室环境下面对随机布置的柑橘,视觉识别定位模块的平均定位精度误差为1.22 cm,采摘过程中柑橘识别成功率达到100%,平均识别时间约为47 ms,机器人柑橘采摘成功率达到80%,平均采摘时间约为15.2 s,验证了采摘机器人平台控制系统程序的可行性,表明所开发的采摘控制系统能够正确、高效地完成整个柑橘采摘作业流程。