空间网状捕获接口的等效抓捕控制

在空间大型机械臂在轨抓捕过程中,其关节柔性及长臀杆的变形会产生较大的末端跟踪及定位误差,因此很难实现成功抓捕.为此,本文研制了一种空间应用的网状捕获对接接口,提高了大臂末端执行器在大定位误差下的抓捕能力.同时,为了提高末端执行器与目标之间的非相对零速情况下的抓捕性能,利用等效抓捕的思想避开了抓捕过程中捕获接口对目标抓钩纠偏力建模复杂的问题,将问题简化为对目标抓钩端点在捕获面上投影的位置跟踪问题,实现了在末端执行器与目标具有一定的相对逃逸速度的情况下的成功抓捕.实验表明,利用本文提出的控制策略增大了网状捕获接口的抓捕容差范围,从而验证了本文提出的控制策略的何效性.     

空间大型末端执行器抓捕容差优化及其仿真

为了使空间大型末端执行器的抓捕操作性能得到最大程度的发挥,不同于传统的从机构设计角度得到末端执行器固定抓捕容差的方法,本文从优化设计学的角度出发,根据末端执行器的工作过程及其原理,将抓捕容差划分为捕获容差和拖动容差两部分,通过分析影响大型末端执行器抓捕容差的结构因素,分别建立了末端执行器捕获容差和拖动容差的数学优化模型,并基于线性加权法和惩罚函数法获得了抓捕容差最优值(128.58mm,128.58 mm,100 mm,15.12,15.12,16.32)T,同时得到了末端执行器本体相对应的结构参数.最终,采用仿真研究方法进行了抓捕容差优化及抓捕性能实验研究.实验结果验证了理论分析的正确性,证明本文提出的末端执行器数学优化模型合理,优化算法正确.     

线驱动柔性机械臂的运动学分析

与传统的由连杆和关节构成的刚性机械臂不同,设计的柔性机械臂无任何刚性结构,外围驱动装置通过嵌在机械臂内部的拉线与柔性机械臂相联系,控制拉线长度的变化量即可调整柔性机械臂末端执行器的位置和姿态。柔性机械臂由弹性材料制作而成,拥有无穷多个自由度,在确保了高安全性、高灵活性的同时,随之也带来运动学和动力学建模复杂、控制难度大等问题。基于分段常曲率的假设,提出了一种运动学建模方法,通过建立3个空间,即驱动空间、虚拟关节空间、任务空间,以及两个映射,即驱动空间-虚拟关节空间映射、虚拟关节空间-任务空间映射,将拉线长度的变化量和柔性机械臂末端执行器的位置和姿态关联起来。仿真结果表明,提出的线驱动柔性机械臂的运动学模型,能较为真实地模拟柔性机械臂在拉线长度变化时的形态,计算末端执行器的位置和姿态。     

空间大型末端执行器柔性钢丝绳的建模与捕获动力学

针对大容差软捕获这一空间捕获操作的重要准则,研制了基于钢丝绳的末端执行器大容差柔性捕获机构.针对钢丝绳具有较大柔性,在窄间应用环境下难于快速连续建模控制的问题,提出丁柔性钢丝绳的离散控制模型,解决了钢丝绳的建模问题.通过钢丝绳的离散模型,分析了末端执行器钢丝绳柔性机构捕获空间自由飞行载荷舱的动力学问题.实验证明钢丝绳模...     

一种自移动空间机械臂末端执行器的研制

针对中小型自移动空间机械臂在轨操作和"换位行走"的任务需求,研制了一种小型化、大容差、高刚度可靠连接的末端执行器及其相应的目标适配器.末端执行器采用单一驱动实现捕获、拉紧锁合、解锁和电连接器插拔等多种功能.考虑捕获容差条件及锁合性能要求,对末端执行器的关键机构参数进行设计.通过ADAMS建立虚拟样机,对捕获容差及锁合的功能性能进行验证.最后通过样机实验对末端执行器的功能进行验证,验证了设计的可行性及仿真的准确性.     

一种空间大容差末端执行器设计方案与仿真分析

根据大型空间机械臂及其在轨服务操作任务的特点,提出了大型空间机械臂末端执行器大容差和软捕获的基本性能要求,同时给出了实现上述基本性能的方法.在此基础上,提出了一种具有大容差性能的机械臂末端执行器设计方案.为了准确获得该类末端执行器的性能指标,完成了该类末端执行器的详细设计,也为后期的动力学仿真分析提供准确的3维模型.最...     

基于MPC564的发动机电控单元硬件设计

介绍一种基于Freescale公司32位高性能控制芯片MPC564的汽油机电控单元硬件设计方案,包括系统电源模块设计、传感器信号处理电路设计、执行器驱动电路设计等。该电控单元采用高性能的处理芯片、高集成度的信号处理模块和驱动模块,为建立可靠的控制系统、实现复杂的控制算法及扩展控制功能奠定了硬件基础。     

用于机械臂末端感知的激光测距传感器设计

为了提高轻型机械臂的末端感知及操作能力,研制了一种用于轻型机械臂末端感知的近距离大测量范围的高集成化微小型激光测距传感器.基于三角法测距原理,以线阵CCD作为光敏感元件,以FPGA作为主控器,根据传感器分辨率的分布要求设计光学系统,使传感器具有测距范围大、测量最近距离近和测量速度快的显著优点.传感器利用光机电一体化设计思想,采用柔性PCB折叠电路、微小型光学元件和机械封装,实现了高集成化微型化设计.所研制的激光测距传感器测距范围为25mm~350mm,体积47mm×50mm×15mm,质量70 g,测量时间1 ms.实验结果表明,该测距传感器易于集成于机械臂控制系统,适用于末端感知,能够有效提高轻型机械臂末端定位精度.     

基于STM32的力反馈型康复机器人控制系统设计

研究了一种基于STM32的力反馈型康复机器人控制系统的设计。采用位置传感器和扭矩传感器检测康复机器人机械臂的位置信息以及机械臂与患者的相互作用力信息,将位置信息与作用力信息送入基于ARM-M3内核的STM32微控制器进行处理,从而实现康复机器人中驱动电机的控制。该系统硬件处理电路包括了扭矩信号的信号调理单元、微控制器控制单元、电机驱动单元以及USB接口单元。经实验验证,本系统可以实现康复机器人的平稳安全的控制。     

头部动作识别系统的硬件设计

介绍了一种用于残疾人的智能交互系统——头部动作识别系统的主体硬件框架,包括头部运动测量单元的设计,采用了三轴陀螺仪L3G4200D和三轴加速度传感器ADXL345.机械臂的执行器驱动单元设计,该部分采用MOSFET驱动,有电流反馈.机械臂结构设计,该部分采用线性执行器电动推杆,推力1500N,速度在2mm/s至60mm/s之间可控,行程200mm,机械臂底盘支持360度全向旋转,整体水平作用距离达1.2m,垂直作用距离1.0m,腕关节支持360度旋转,夹持机构开合行程30mm,可以应对一般家庭应用.为机械臂控制算法的工作提供了硬件平台.     

A flexible-arm as manipulator position and force detection unit

This paper presents a self-sensory robot arm to two basic sensing problems in control of flexible manipulators: detection of the position and orientation variations due to structural deformation and detection of the contact force of end-effector when manipulator interacts with its environment. Taking advantage of structural flexibility, a flexible robot arm with strain gauges distributed on it acts as a sensing unit. The position and orientation of flexible arm are expressed as a function of curvature of the arm. An interpolation technique gives this continuous curvature function from a finite set of measurements made with strain gauges. A relation between strain measurements and endpoint force of flexible arm is developed and the contact force of end-effector is then determined using a force propagation algorithm. The proposed technique and algorithm were implemented and evaluated in a laboratorial flexible arm. Experimental validations using a vision system and two force sensors have shown that the self-sensory flexible arm can provide accurate endpoint position and force in both static and dynamic loading situations.     

Modelling and Model Fitting of Flexible Robots – a Multibody System Toolkit Approach

During the last decade robots with flexible links became a popular research object for control engineers. This is because of their sophisticated properties referring to feedback control, e.g., non-minimum phase behaviour in end-effector control. Massive problems already occur trying to obtain an accurate analytic model for multilink flexible robots. This paper presents an effective way for numerical modelling of multilink flexible robots using the multibody system toolkit MBILE. The experimental model fitting to a laboratory test bed of a two-link flexible robot is documented.     

Implementation of the velocities of the end-effector with the distributed arithmetic architecture

The fast implementation of the linear and of the angular velocities of the end-effector of robotic manipulators, using the distributed arithmetic technique is described. The linear and angular velocities of the end-effector as well as the positional and the orientational jacobian matrices is calculated by a cascade configuration of two pipelined arrays. The building blocks of the arrays are the distributed arithmetic-based circuits that implement the matrix-vector multiplications involved in the calculations. The digit-serial configuration of the proposed implementation of the linear and angular velocities of the end-effector is described, while the serial and the parallel configurations may result as special cases of the digit-serial configuration. The proposed distributed arithmetic computer architecture may be used in the real-time operation of the robot control system that requires the on-line computation of the position, of the linear and angular velocities of the end-effector and of the Jacobian matrix.     

Impedance Control of Flexible Robot Arms with Parametric Uncertainties

This paper presents an adaptive impedance control strategy for flexible manipulators by using an end-effector trajectory control approach. The impedance control objective is converted into tracking a trajectory generated by a designed ideal impedance model. A manifold is designed to prescribe desirable performance of the system. An adaptive control scheme is derived in such that the motion of the system will converge and remain to the ideal manifold for the case of parametric uncertainties. Stability of the control system is analyzed. Simulations are carried out to demonstrate the effectiveness of the proposed control method.     

Efficient energy management of CO2 capture plant using control-based optimization approach under plant and market uncertainties

This paper employs a control-based optimization algorithm encompassing of an intelligence model predictive control (MPC) scheme and mixed integer non-linear programming (MINLP) for coal-fired power plant retrofitted with flexible solvent-based post combustion CO₂ capture (PCC) plant (integrated plant). The agility and robustness of the developed control algorithm (MPC) is demonstrated through the control response time and efficiency of energy requirement including the financial and operational benefits of the plant subjected to plant and market uncertainties. While, the MINLP is utilized to forecast plant operational modes by ensuring the operational fidelity of integrated plant. This involves utilization of historical (2011) and forecast (2020) market conditions (electricity tariff and carbon price) subject to maximum plant net operating revenue. The outcomes show that the future power plant will operate in mixed operation modes, for instance in unit turndown and load following modes, which contribute to a minimum capture energy penalty at 3.13 MJ_th/tonne CO₂. Moreover, under the same year (2020), MPC exhibits superior control performance by satisfactorily obtain 94% actual CO₂ capture from the ideal cumulative CO₂ capture. Additionally, the integrated plant is capable to resume approximately 96% actual revenue from the ideal net operating revenue projected by the control-based optimization algorithm. The algorithm demonstrates that the installation of control system package (MPC) into the flexible PCC plant associated with coal-power generator could contribute to efficient energy management subjects to unprecedented uncertainties.     

Comparison of four different heuristic optimization algorithms for the inverse kinematics solution of a real 4-DOF serial robot manipulator

In this study, a 4-degree-of-freedom (DOF) serial robot manipulator was designed and developed for the pick-and-place operation of a flexible manufacturing system. The solution of the inverse kinematics equation, one of the most important parts of the control process of the manipulator, was obtained by using four different optimization algorithms: the genetic algorithm (GA), the particle swarm optimization (PSO) algorithm, the quantum particle swarm optimization (QPSO) algorithm and the gravitational search algorithm (GSA). These algorithms were tested with two different scenarios for the motion of the manipulator’s end-effector. One hundred randomly selected workspace points were defined for the first scenario, while a spline trajectory, also composed of one hundred workspace points, was used for the second. The optimization algorithms were used for solving of the inverse kinematics of the manipulator in order to successfully move the end-effector to these workspace points. The four algorithms were compared according to the execution time, the end-effector position error and the required number of generations. The results showed that the QPSO could be effectively used for the inverse kinematics solution of the developed manipulator.     

XDPS系统在600MW机组中的应用

针对国产DCS缺乏大型机组应用经验的问题,介绍了国产DCS系统XDPS在600 MW亚临界火电机组中的具体应用,描述了贵州盘南电厂3#,4#机组DCS及公用系统的I/O配置、硬件配置、网络拓扑结构及软件控制策略,控制范围包括DAS,MCS,SCS,FSSS,TBC和ECS等子系统。优化的I/O分布,冗余容错光纤环网,全能操作员站,分散布置冗余备用的控制器DPU,灵活的通讯接口,方便的组态工具,完善的控制策略说明XDPS400 系统对600 MW及以上容量大型火电机组具有可靠、完整的解决方案。     

Autonomous robotic capture of non-cooperative target using visual servoing and motion predictive control

This paper presents a framework for autonomous capture operation of a non-cooperative mobile target in a 3-dimensional workspace using a robotic manipulator with visual servoing. The visual servoing with an eye-in-hand configuration is based on motion predictive control using Kalman filter for the on-line state and parameter estimation of the target. A transitional decision making process is developed to guide the robotic manipulator between the different phases of the capture operation by employing a custom metric that translates visual misalignments between the end-effector and the target into a guidance measurement. These phases include the target acquisition and approach stage and the alignment and capture phase. Experiments have been carried out on a custom designed and built robotic manipulator with 6 degrees of freedom. The objective is to evaluate the performance of the proposed motion predictive control scheme for the autonomous capturing task and to demonstrate the robustness of the proposed control scheme in the presence of noise and unexpected disturbances in vision system, sensory-motor coordination and constraints for the execution in real environments. Experimental results of the visual servoing control scheme integrated with the motion predictive Kalman filter indicate the feasibility and applicability of the proposed control scheme. It shows that when the target motion is properly predicted, the tracking and capture performance has been improved significantly.     

单臂式空间机械臂捕捉空间目标问题研究

以空间机械臂系统的动量守恒关系式为基础,对空间机械臂抓取空间目标过程中的碰撞问题进行了分析,提出了“直臂抓取”与“广义直臂抓取”概念,详细推导了满足基座质心、系统质心及工作端点共线的机械臂构型,得到了碰撞力方向矢量与基座、系统质心重合的角度关系式．满足关系式的空间机械臂构型可有效的减少碰撞力对于系统角动量的影响,进而避免混合体控制问题的关节限制与力矩限制．通过仿真验证了方法的有效性．