激光聚焦次镜支撑小型三自由度机构运动分析

提出了利用一种可实现一个移动和两个转动的小型3自由度(3-DOF)并联机构来控制支撑激光聚焦次镜的方案。采用传统的欧拉角描述动平台运动方式,建立了小型3-PRS机构的运动学模型,分析了机构的正、逆运动学性能,进行了包括约束雅克比矩阵的建立和伴生运动的求解。基于运动学分析,定性分析了机构的奇异位形。联合ADAMS与MATLAB,计算了机构的可达工作空间,动平台绕x轴最大运动角度为15.167 1;绕y轴最大运动角度为13.319 4;沿z轴方向的移动大约为9.954 1 mm,分析证明该小型3-PRS机构完全满足支撑激光聚焦次镜结构的设计要求。     

新型惯性压电驱动机构的仿真分析

提出通过机械方式控制压电驱动机构和支撑面之间正压力的有序变化,形成有规律的新型惯性压电驱动机构的研究方案。分析了机构的运动机理,建立了机构的动力学模型,应用现代控制理论,利用Matlab对机构进行运动学仿真,得到了机构位移仿真曲线,设计、制作了驱动机构样机,并作了相关的性能测试。仿真计算和试验结果表明了运动机理和动力学模型的正确性。     

外参数激励MOEMS扫描镜动力学过程与追踪控制

随着MOEMS扫描镜的发展，其较高的谐振频率及IC兼容的低成本等优点在激光3D图像传感器中应用前景广阔，研究外参数激励MOEMS扫描镜动力学特性与控制问题具有重要的理论和应用价值。从欧拉方程出发，建立静电驱动MOEMS扭转动力学模型，利用四阶Runge-Kutta算法仿真表明:在外参数指令信号激励下，MOEMS扫描镜扭转状态经历阻尼运动、周期、倍周期和混沌等动力学过程，其中周期运动存在着一个较大的参数控制范围。根据Lyapunov稳定性理论，设计了一种连续混沌系统追踪控制器，使受控的MOEMS扫描镜扭转状态收敛于任意期望的指令信号。实验表明，李萨如图指令信号适用于激光3D图像传感器；几何矢量指令信号适用于激光3D打印系统，理论分析与实验相一致。     

精密两维转镜的动力学仿真与控制误差分析

精密两维转镜作为激光角度欺骗干扰半实物仿真试验系统中模拟弹目、弹干扰视线运动的重要设备,其控制误差是影响视线运动模拟精度的重要因素,进而影响半实物仿真试验精度。以多体系统动力学方法推导了精密两维转镜的机电分析动力学模型,采用计算力矩法设计了两维转镜的轨迹跟踪控制器,并在Matlab/Simulink环境中对建立的反映转镜动态特性的数学模型进行了仿真,转镜方位、俯仰轴对等效正弦输入信号的角位置跟踪误差分别为2.2 mrad与3.5 mrad,结果表明:模型可实现对引导输入的角位置信号的高精度跟踪控制。     

四旋翼无人机仿真控制系统设计

为了实现四旋翼无人机的自稳定控制,对四旋翼无人机进行了动力学建模与控制。在建模时利用机理建模和实验实测相结合的方法,建立小型四旋翼飞行器的动力学仿真模型;并通过准LPV法将非线性模型线性化,在飞行器模型解耦的4个通道上分别设计PID控制器,且在Matlab/Simulink平台上对系统整体进行仿真。仿真结果表明,该动力学模型和PID控制器可以有效地实现飞行器的自稳定控制,为后续的四旋翼飞行器的控制研究打下基础。     

粘片机焊头机构快速启停最优运动速度规划

对于高速精密微电子封装操作,必须降低焊头振动。基于ADAMS多体动力学和控制系统分析与优化模块,建立了粘片机焊头机构动力学PID控制模型。通过联合仿真优化,实现了摆臂式焊头机构在满足最大扭矩和残余振动约束下运动时间最短的运动速度规划,为点位运动精密定位系统的最优控制器的设计提供了一个简单的实现途径。     

次镜支撑动力学建模及其风载作用分析

为了对望远镜次镜支撑系统动力学性能与风载响应进行理论分析,建立了正交弹簧模型,计算了风载功率谱的解析解。首先利用正交弹簧模型对次镜的支撑结构进行动力学理论建模,求得2个相等的频率为61.9578Hz并使用有限元软件MSC.Patran/Nastran进行了仿真,得到2个相等的频率为66.305Hz,验证了简化的正确性;进而将其应用于风载功率谱分析,得出望远镜对风载的响应与频率的关系,以及风载作用的解析解和有效风载能量分布主要在0.15 Hz以下的结论。     

粘滑驱动式小型运动平台的动力学分析

为解决微纳操作中驱动技术方面的问题,该文研制了一种粘滑驱动式小型运动平台;基于已构建的平台结构,继而建立了粘滑驱动系统动力学模型。该动力学模型在引入LuGre摩擦模型的基础上,分别对压电叠堆的电学模型、驱传动系统机械动力学模型进行建模,最终得到统一的粘滑驱动系统模型,并利用Matlab/Simulink对模型进行仿真及分析。分析结果表明,平台位移随着预压力增大而减小,而随着移动台质量的增大而增大。最终经过实验结果与仿真数据对比可知两者基本一致,验证了该模型的准确性。     

一种低耦合位移动镜支撑机构静动态性能分析

为控制FTIR光谱仪中迈克尔逊干涉仪的动镜做一维的精密直线运动,研究了一种低耦合位移的动镜支撑机构。利用单平行和双平行四杆机构的优点,基于柔性铰链设计了一种动镜支撑机构。根据材料力学及机构动力学理论,对基于压电陶瓷（PZT）驱动器驱动的动镜支撑机构系统的静、动态性能进行了分析。仿真结果表明,低耦合位移动镜支撑机构在外力对称作用时无垂直耦合位移,在外力偏移1 mm非对称作用时其耦合转角的数量级（以度为单位）为10-6;在输出相同位移时,动镜机构的最大应力约为双平行四杆机构的0.5倍;动镜机构的基频f为211.3 Hz,PZT驱动器和动镜机构构成的机电系统的固有频率fn为823.7 Hz,fn约为f的4倍,满足动镜支撑机构系统的动态性能要求。该研究为后续的进一步研究打下了基础,具有一定的工程价值及理论指导意义。     

波纹梁夹持型双平行四边形柔性机构性能分析

为解决传统双平行四边形柔性机构中二级运动平台欠约束问题,设计了一种波纹梁夹持型对称双平行四边形柔性机构。首先,提出了一种基于正弦曲线的波纹梁结构,并将其安装在对称双平行四边形机构的2个二级平台之间;其次,建立了机构静力学解析模型,并利用拉格朗日方程建立了动力学模型;最后,利用有限元和实验方法对其静、动力学性能进行了仿真和测试。结果表明:该机构在没有改变机构运动刚度和一阶固有频率的情况下,对二级平台进行了有效约束,从而提升了双平行四边形机构的高阶固有频率,能够有效改善传统双平行四边形机构的动力学特性和抑制振动能力。     

空间望远镜次镜六自由度调整机构精密控制

为满足空间望远镜在轨主动光学控制需求,需要精密调整次镜相对于主镜的六自由度位姿,为此,针对6-PSS Stewart平台构型的次镜精密调整机构,设计完成了基于并联机器人关节空间方法的运动控制系统。以DSP和FPGA为核心处理器,编码器为反馈元件,集成电机三相桥为驱动元件,设计完成了次镜六自由度调整机构的运动控制电路。基于次镜调整机构的顶层逆运动学模型和底层连杆控制系统,设计完成了次镜六自由度调整机构的运动控制算法,该方法参数易于调整,利于工程实现,满足空间运动机构高可靠性调整需求。试验结果表明,该运动控制系统能够满足全行程内0.7 m （位移）和3（角度）运动调整精度需求,能够满足空间望远镜主动光学调整任务。     

Design and dynamics of a 3-DOF flexure-based parallel mechanism for micro/nano manipulation

This paper presents the mechanical design and dynamics of a 3-DOF (degree of freedom) flexure-based parallel mechanism. Flexure hinges are used as the revolute joints to provide smooth and high accurate motion with nanometer level resolution. Three piezoelectric actuators are utilized to drive active links of the flexure-based mechanism. The inverse dynamics of the proposed mechanism is established by simplifying flexure hinges into ideal revolute joints with constant torsional stiffnesses. Finite element analysis is used to validate the performance of the proposed 3-DOF flexure-based parallel mechanism. The interaction between the actuators and the flexure-based mechanism is extensively investigated based on the established model. Experiments are carried out to verify the dynamic performance of the 3-DOF flexure-based mechanism.     

4-DOF多功能机器人运动控制算法的研究

随着机器人技术的不断发展,机器人在现在社会发展中发挥着越来越重要的作用。文中对实验室研发的多功能4-DOF机器人的运动控制相关问题进行研究。首先对4-DOF机器人的机构整体设计并PROE三维建模,然后通过基于D-H法建立机械臂坐标系,对4-DOF机器人进行运动学正逆解分析,在逆解计算中,提出了当两轴平行两轴耦合的计算方法,即将两轴关节角视为整体计算,再利用代数方法依次得出单个关节角。同时针对机械臂的连续轨迹运动给出轨迹规划的方法,为设计机械臂控制器的实现和机械臂的运动控制提供了依据。     

The Tricept robot: dynamics and impedance control

The Tricept is a novel industrial robot characterized by a hybrid kinematic design featuring a three-degrees-of-freedom (3-DOF) structure of parallel type and a 3-DOF spherical wrist. In this work the authors focus on the derivation of a dynamic model to be used for both simulation and control purposes. Two different approaches are discussed and compared in terms of inverse dynamics computation. Then, a model-based control is derived aimed at enforcing a 6-DOF impedance behavior at the end effector to manage interaction with the environment. Simulation results are presented to evaluate the accuracy of an approximate dynamic model computation as well as to test the effectiveness of the proposed impedance control strategy.     

An Experimental Study of a Redundantly Actuated Parallel Manipulator for a 5-DOF Hybrid Machine Tool

This paper deals with the experimental study of a redundantly actuated parallel manipulator for a 5-DOF hybrid machine tool. Based on the kinematics of the redundantly actuated parallel manipulator, the inverse dynamics is derived by using the virtual work principle. A position and force switching control strategy is used for the two extendible chains of the parallel manipulator. Further, the difference predictive control is presented for the extendible chain with force mode. The parallel manipulator is incorporated into a 5-DOF hybrid machine tool. Linear and circular contouring experiments of both the hybrid machine tool as well as its corresponding nonredundant counterpart with the redundant limb removed are conducted to evaluate the machine performance. Finally, the machine experiment is used to demonstrate the machine's applicability.      

Exoskeletal master device for dual arm robot teaching

Dual arm robots are used as humanoid or industrial robots for assembly work. Each arm of these robots is generally composed of 7-DOF to mimic the human arm. For motion teaching of this 7-DOF robot arm, upper limb exoskeletal master devices can be used, and each arm of the upper limb exoskeletal master device can also be composed of 7-DOF. However, the motions of the human shoulder are complex and the lack of DOF in the exoskeletal master device limits the wearer's motions and makes the wearer feel uncomfortable. We propose a compact-sized exoskeletal master device, each of whose arms are composed of two serially connected parts. One is a 6-DOF shoulder–elbow mechanism and the other is a 3-DOF wrist mechanism. The 6-DOF mechanism serially connects the base frame near the shoulder to a point on the forearm, and the center of rotation of the shoulder joint is shifted to the outside of the human shoulder. In addition, the 6-DOF mechanism includes a long stroke but short reduced-length prismatic joint. This 6-DOF mechanism enables unconstrained and comfortable shoulder motions. The 3-DOF wrist mechanism corresponds to forearm pronation/supination, wrist flexion/extension, and wrist adduction/abduction. The closed-loop inverse kinematic scheme is applied for the dual arm robot control in the task space. The performance of the exoskeletal master devices and control strategies are verified through experiments using a 14-DOF dual arm slave robot.     

空间光学遥感器精密次镜调整机构设计及试验

随着空间光学遥感器地面分辨率逐步提高,长焦距、大口径相机成为重点研究方向。为了克服重力变化、复合材料变形等因素带来的天地不一致性的问题,次镜调整成为校正光学遥感器离焦和主次镜相对位置变化的关键技术之一。将次镜柔性支撑、精密直线驱动与柔性铰链传动技术相结合,设计了一套高精度次镜调整机构。首先介绍了该套机构的光机构成、工作原理及传动链路,然后对超轻次镜、高精度直线致动、高精度调焦传动等设计分别进行了阐述,最后介绍了力学环境试验后的调整精度测试情况。试验结果表明,该套精密调整机构实测调整行程大于±120μm,轴向调整步距精度0.18μm (3σ值),调整行程内次镜的最大平移误差为1.30μm,最大倾斜误差为1.93″,具有调整范围宽、调整精度高的特点,满足空间光学遥感器精密次镜调整的要求,已成功在轨应用于北京三号B卫星0.5 m级高分辨率空间相机。     

Implementation of a novel large moving range submicrometer positioner

A novel, compact and two degree-of-freedoms (DOF) submicrometer positioner with a large moving range is presented in this paper. The design of the positioner utilizes a monolithic parallel flexure mechanism with built-in electromagnetic actuators and eddy current sensors to achieve the precision 2-DOF motion. The travel range of the positioner is 1000 μm/5 mrad and which depend on the eddy current sensor’s range of measurement (ROM) and electromagnetic actuator’s effective length. The analytical model and its dynamics were analyzed and derived. The whole control architecture takes the measured configuration parameters and endeavors to control the positioner motion by regulating the currents in the electromagnetic actuators. To increase the compactness and stability of the positioner, a self-tuning adaptive (STA) controller was analyzed and proposed. From the experimental results, satisfactory performances of the system, including stiffness and precision, have been successfully demonstrated.     

新型副镜并联调整机构非线性特性及校正

为满足望远镜副镜结构定位精度的要求,提出一种固定杆长杆端轴向平移运动模式的六杆并联机构。从微分几何的观点研究了该机构输入关节空间向量与输出工作空间向量之间的非线性运动学特性,并采用曲率概念度量解轨迹的非线性弯曲。通过与雅可比矩阵的对比分析可知,采用曲率度量并联机构的非线性和采用雅克比矩阵反映的瞬时线性性质一致,所设计的副镜并联调整机构在整个运动行程范围内的最大非线性误差约为3.15 μm。测试结果表明:采用多项式误差曲线拟合校正之后,该副镜调整机构三维平移重复定位精度小于2.6 μm,二维旋转重复定位精度小于1.8″,满足实际望远镜观测的需要,采用的曲率度量法也可以为其他并联机构的非线性分析和校正提供一种新的思路。