Optimum design of a three-dimensional serial robot manipulator

A systematic and mathematical optimization methodology is presented for the optimal design of a three link, revolute joint, three-dimensional manipulator which must perform specific prescribed tasks. The objective of interest is the minimization of average torque requirement. In particular circular and eccentric closed task paths are considered. The optimization is carried out with the link lengths and the positional coordinates of the base taken as the five design variables, and subject to assembly and geometric constraints imposed on the system. In particular restrictions are placed on the joint angle between the links and on the link lengths. The minimization is successfully performed by the application of Snymans robust dynamic trajectory method for unconstrained optimization, to a penalty function formulation of the constrained problem.     

Open architecture dynamic manipulator design philosophy (DMD)

This paper presents a generic and universal architecture design for robotic manipulators. A flexible approach is taken to develop the design philosophy throughout, resulting in a hardware architecture that is portable, can be integrated and enables the implementation of advanced control methods. A software kernel of management, supervision and control was developed in order to obtain an easy user interface to the robotic researcher. The application of many such controls has, traditionally, often been severely restricted in partial commercial robotic systems because of limitations associated with their controllers; rather than the arms themselves.     

一种嵌入式串口共享服务器的设计

针对目前大多数串口服务器仅支持主副机而不支持多主机、不支持Modbus TCP转Modbus RTU等问题,设计了一种嵌入式串口共享服务器。该串口共享服务器采用Cortex-M3内核的LM3S9B92芯片设计,实现了单芯片以太网到3个串口的转换功能。测试结果表明,该串口共享服务器收发数据准确,通信速率高,且具有Modbus TCP转Modbus RTU功能。     

通信型智能操作器的设计与应用

针对电站锅炉均衡燃烧监控系统,研制开发了基于MODBUS现场总线的双通信型智能操作器。保证了锅炉的给煤量和送风量的合理匹配,使其燃烧最佳。介绍了双通信型智能操作器的硬件设计、软件设计及其数字双通信的实现。     

Contact force and torque sensing for serial manipulator based on an adaptive Kalman filter with variable time period

Contact force and torque sensing approaches enable manipulators to cooperate with humans and to interact appropriately with unexpected collisions. In this paper, a mode-switching moving average with variable time period is proposed to reduce the effects of measured motor current noise and thus provide improved confidence in joint output torque estimation. The time period of the filter adapts continuously to achieve optimal tradeoff between response time and precision of estimation in real-time. An adaptive Kalman filter that consists of the proposed moving average and the classical Kalman filter is proposed. Calibration routines for the adaptive Kalman filter take the measured motor current noise and errors in the speed data from the individual joints into account. The combination of the proposed adaptive Kalman filter with variable time period and its calibration method facilitates force and torque estimation without force/torque sensors. Contact force/torque sensing and response time assessments from the proposed approach were performed on the Universal Robot 5 manipulator with differing unexpected end effector loads. The combined force and torque sensing method led to a reduction of the estimation errors and response time in comparison with the pioneering method, and the effect is further improved as the payload rises. The proposed method can be applied to any robotic manipulators as long as the motor information (current, joint position, and joint velocities) are available and consequently the cost will be reduced dramatically from methods that require load cells.     

六维腕力传感器非线性正解耦方法设计

多维力传感器利用其多个转换单元完成测量加载于其结构上未知负载的作用效果,解耦是其设计的重要组成部分。针对传统静态线性解耦方法的不足,试图将传统线性解耦方程扩展为多项式结构,受其多元高次方式通解形式的启发,构造了一种多项式非线性静态正解耦方程,该方法无需传统线性解耦方法中的曲线拟合、逆解,不依赖以系统是线性为前提,且方程可以扩展成任意结构的多项式。实验结果表明:该方法能降低输出耦合误差。     

Design of a six-axis wrist force/moment sensor using FEM and its fabrication for an intelligent robot

This paper describes the design of a six-axis force/moment sensor using FEM (finite element method) and its fabrication. In order to safely grasp an unknown object using an intelligent hand in robot, the hand has to perceive the weight of it. The weight is calculated by forces F_x, F_y, F_z measured from the six-axis wrist force/moment sensor attached to an intelligent robot's hand. And, in order to accurately push and pull an object, forces and moments should be measured. Also, the position of the robot's finger contacted on an object are calculated by forces F_x, F_y and F_z, and moments M_x, M_y and M_z measured from the six-axis wrist force/moment sensor. Therefore, an intelligent robot's hand should get a six-axis wrist force/moment sensor that can measure forces F_x, F_y and F_z, and moments M_x, M_y and M_z simultaneously. The size of the six-axis force/moment sensor for an intelligent robot’ wrist is very important. If its diameter is larger or its thickness (length) is longer, it cannot be mounted in robot's wrist or it will break down under the applied moment M_x or M_y. So, its size is similar to that of the wrist of human being, that is, the diameter is about 60–80 mm and the thickness (length) about 20–40 mm. But the manufactured sensors are not proper in size for the intelligent robot's wrist. Thus, the six-axis force/moment sensor should be developed for the intelligent robot's wrist.In this paper, the structure of a six-axis wrist force/moment sensor was modeled for an intelligent hand in robot newly. And the sensing elements of it were designed by using FEM and were fabricated by attaching strain-gages on the sensing elements. And, the characteristic test of the developed sensor was carried out. The rated outputs from FEM analysis agree well with the results from the experiments. The interference error of the sensor is less than 2.85%.     

多功能智能操作器的设计

介绍基于单片机设计的多功能智能操作器原理及软硬件实现方法，该系统可完成操作器和伺服放大器两者的功能，控制电动执行机构或调节阀动作。实际使用说明，该系统具有优良的控制效果和极高的可靠性。     

Design of a reconfigurable platform manipulator

Modular robots introduce a new dimension to flexible automation in terms of hardware flexibility, in addition to the software flexibility, in terms of yielding individual global optimal configuration for each of the tasks at hand. The mechanical structure of fully parallel manipulators is very suitable for reconfiguration since those manipulators are actuated in parallel. To really achieve effective and convenient reconfiguration, however, there are design and planning issues to be addressed. In this article the conceptual design and actual construction of an experimental platform manipulator are presented. This experimental platform is built as a tool to aid our research on the design and planning issues related to reconfiguration of parallel manipulators. © 1998 John Wiley & Sons, Inc.     

大量程六维力传感器设计与标定研究

为提高大量程六维力传感器的灵敏度,设计了一种适用于机械臂末端的应变式传感器.该传感器采用十字梁式弹性体结构,通过优化应变梁结构和合理布置应变片等方式,使传感器在大量程条件下仍具有较高的刚度和灵敏度.使用有限元法分析验证了传感器应力分布的合理性,并根据最小二乘法标定原理对传感器进行解耦标定实验,实验结果表明:传感器静态性能良好,最小灵敏度为0.375 mV/N,满足使用要求.     

Design and performance evaluation of an actively compliant underwater manipulator for full-ocean depth

An underwater manipulator is described that can exhibit a wide range of compliance through a combination of mechanical design and software control and its performance characterized. The manipulator has been used in conjunction with the JASON Remotely Operated Vehicle at full-ocean depth. The major goal of the design was to produce a manipulator that can actively control the interaction forces with the work task in the hostile deep-ocean environment. The manipulator's performance has been characterized in the lab and its overall operational utility has been confirmed during tests to depths of approximately 4000 meters, including an archaeological excavation at 700 meters depth in the Mediterranean. The manipulator uses high performance brushless DC servomotors driving the joints though low-friction, zero-backlash reductions of moderate ratio consisting of cables and pulleys. Each joint is highly backdriveable and has a large range of rotation. This approach permits a variety of force control schemes such as impedance control to be implemented with no sensors other than the displacement sensors integrated with the brushless motor. It also permits high-quality torque servomechanisms to be directly implemented. This article outlines the design and illustrates the performance of a single joint in terms of friction, stiffness, and in implementing variable compliance and as a closed-loop torque servo.     

Artificial neural network-based kinematics Jacobian solution for serial manipulator passing through singular configurations

Singularities and uncertainties in arm configurations are the main problems in kinematics robot control resulting from applying robot model, a solution based on using Artificial Neural Network (ANN) is proposed here. The main idea of this approach is the use of an ANN to learn the robot system characteristics rather than having to specify an explicit robot system model.Despite the fact that this is very difficult in practice, training data were recorded experimentally from sensors fixed on each joint for a six Degrees of Freedom (DOF) industrial robot. The network was designed to have one hidden layer, where the input were the Cartesian positions along the X, Y and Z coordinates, the orientation according to the RPY representation and the linear velocity of the end-effector while the output were the angular position and velocities for each joint, In a free-of-obstacles workspace, off-line smooth geometric paths in the joint space of the manipulator are obtained.The resulting network was tested for a new set of data that has never been introduced to the network before these data were recorded in the singular configurations, in order to show the generality and efficiency of the proposed approach, and then testing results were verified experimentally.     

基于时间函数的并联六维力传感器量程设计

针对并联六维力传感器设计与制造过程中面临的解耦计算复杂、量程确定困难、实用性不强等问题,应用螺旋理论,推导了其受六维外力向测量分支反作用力的映射矩阵;基于工程实际,提出并建立了并联六维力传感器测量分支作用反力的时间函数模型;提出了一种在特定工作环境下测量分支量程的确定方法.以Stewart并联结构为例,针对曲面打磨作业,确定了其测量分支的量程,验证了时间函数模型的正确性和可行性.研究内容对提高并联结构六维力传感器的工程应用性有重要的实践价值.     

Time-scaling control of an underactuated manipulator

Position control of an underactuated manipulator that has one passive joint is investigated. The dynamic constraint caused by the passive joint is second-order nonholonomic. Time scaling of the active joint trajectory and bidirectional motion planning from the initial and the desired configurations provide an exact solution of the positioning trajectory. The active and passive joints can be positioned to the desired angles simultaneously by swinging the active joints only twice. Feedback control constrains the manipulator along the planned path in the configuration space. Simulation and experimental results show the validity of the proposed methods. © 1998 John Wiley & Sons, Inc.     

Design of a reconfigurable planar parallel manipulator

This work presents the design of a reconfigurable planar parallel manipulator (RPPM). The RPPM is designed to act as a testbed manipulator for theories on redundant actuation of parallel manipulators and can reconfigure into three different revolute-jointed mechanism types: a 2-branch 2-DOF (degree-of-freedom) 5-bar mechanism; a 2-branch 3-DOF 6-bar mechanism; and a 3-branch 3-DOF 8-bar mechanism. The design of the RPPM allows for any shoulder or elbow joint to be actuated. In this work, the criteria and constraints of the design are presented. The final design of the RPPM is shown, followed by a discussion of the final design and how it relates to the initial design criteria and constraints. © 2004 Wiley Periodicals, Inc.     

基于PLCopen的六轴工业机器人运动控制功能块设计

针对工业机器人控制系统的开放性要求,设计符合PLCopen规范的六轴工业机器人运动控制功能块。基于CodeSys软件开发环境,结合SMC_CNC库中数组、结构体和功能块,采用IEC61131-3编程语言开发了六轴工业机器人运动控制功能块,包含：坐标变换、正逆运动变换、直线与圆弧插补运动等;在此基础上,开发了一系列机器人运动控制指令和可视化编程界面。最后,以埃夫特ER50六轴工业机器人为实验对象,采用研制的机器人运动控制器,实施机器人编程控制实验,结果表明所开发的机器人运动控制功能块及其指令达到了设计要求。     

Modelling and simulation of an underwater manipulator

Recently, applications of articulated manipulators have increased to include extreme environments such as underwater and space. Simulation systems to support the design and control of industrial robots have been developed in many laboratories, and some high-speed calculation methods for inverse dynamics analysis of manipulators with series connections have been proposed. This paper deals with the dynamic simulation and modelling of underwater articulated manipulators. The dynamics of the above manipulators are formulated to evaluate the influence of the added mass tensor, the added inertia tensor, and fluid drag, and the lift on each arm according to classical Newton-Euler mechanics. Moreover, by generalizing this model, we can discuss the dynamics of a manipulator with dual arms and simulate some constrained motion of an end-effector. As an example of inverse dynamics analysis, the force and moment of a nine degrees of freedom (d.o.f.) manipulator with dual arms are analysed. As an example of direct dynamics analysis, hybrid control of both the force and the position of a 6 d.o.f. manipulator is simulated.     

一种基于双E型膜片的微小六维力传感器的设计

基于双E型膜片结构的六维力传感器用于常规环境下的机器人操作已有成熟应用,探讨将该结构应用于微纳环境下的机器人操作的可能性。首先介绍了该弹性体结构的测力原理,并用有限元分析软件对弹性体的静态和动态特性进行了仿真。结果表明此种结构的六维力传感器可在微纳环境下测力,并具有各向灵敏度高、线形好、维间耦合小等优点。