步进电机驱动六自由度并联运动平台设计

为了能够在实验室内进行小型仪器元件的六自由度运动模拟和演示,设计了以步进电机驱动滚珠丝杠传动的小型六自由度并联运动平台。通过运动学反解建立了算法公式,应用Matlab仿真,得出了平台运动时各支路长度的变化曲线,验证了求解算法的正确性;运用Kutzbach-Grubler公式分析了电驱动UPU结构形式并联运动平台自由度的计算方法。根据给定参数建立了平台的三维模型,进行了结构协调性检测,并完成了步进电机驱动的六自由度平台的实体结构研制。将Lab VIEW组态软件与Matlab脚本解算程序结合,用于对平台的运动控制。测试结果表明:平台完全可以按照预定轨迹进行空间6个自由度的运动,实现对小型仪器元件的运动模拟。     

基于AVR平台的六自由度仿人机械手臂控制算法研究

传统机械手臂各关节常用电机来驱动,其驱动系统较为复杂,设计难度较大。提出以AVR为控制平台,以舵机作为机械臂各关节驱动,并着重介绍了基于舵机特有的工作方式而提出的一种可以对该机械臂各关节运动速度、方向和运动量进行控制的算法。该算法同时还具备可扩展性等优点,即可以对由舵机驱动的更多自由度的机械手臂进行实时控制。     

2R耦合驱动关节动力学建模与参数辨识

围绕护理机器人的人机安全接触和轻量大负载需求,提出了一种2R耦合驱动关节构型,并解决了耦合驱动动力学建模问题,为高性能运动控制器搭建提供基础。该关节设计紧凑、负载能力强,两个伺服电机经过三级减速后,通过差动结构实现两自由度耦合输出,且表面光滑适宜与人接触。通过运动学分析了耦合驱动的原理,利用拉格朗日法建立了耦合驱动动力学模型。为解决速度零点摩擦力不连续,造成基于模型的控制器运动性能变差的问题,引入了连续可微摩擦模型,利用连续可微特性采用灰色模型提高了辨识精度。研制了机器人关节样机,进行了关节解耦、摩擦数据采集、参数辨识及轨迹跟踪等试验,结果表明所设计的耦合驱动关节可以完成周转、俯仰两个转动自由度的单独及耦合运动,并且输出扭矩与重量的比值达到了143.6 N·m/kg,可以满足轻量大负载护理需求,同时基于所建立动力学模型的运动控制可以显著提高轨迹跟踪的准确性。     

(2SPS/U)&(2SPS/RR)型并联拟人机械臂的设计与运动学分析

针对现有仿生拟人机械臂连续性差、稳定性差和惯性冲击大的问题,提出了一种新型并联拟人机械臂,可以模拟人的腕关节、肘关节、肩关节动作,采用(2SPS/U)&(2SPS/RR)的二级耦合并联机构来驱动各个关节动作.为得到其运动学正反解,利用封闭矢量法和牛顿迭代法计算得到两级并联机构的运动学正反解;并将整个拟人臂的机构构型进行...     

肩离断多自由度机器人型假肢肩部气动平衡机构的优化设计

肩离断多自由度机器人型假肢拥有6个自由度,其肩部前后摆采用旋转电机驱动,外摆采用直线电机驱动。为避免空间干涉以及减小驱动力矩,采用了一种气动支撑杆来实现对大臂关节重力矩的平衡。设计了气动支撑杆平衡结构形式,确定了结构设计中的待优化变量,建立起结构的运动数学模型,构造了结构设计的约束与目标函数。用有约束问题的最优化算法求得本结构的综合最优解,最后输出了优化设计计算结果及其运动仿真图形。     

NOVEL 6-DOF WEARABLE EXOSKELETON ARM WITH PNEUMATIC FORCE-FEEDBACK FOR BILATERAL TELEOPERATION

A particular emphasis is put on a novel wearable exoskeleton arm, ZJUESA, with 6 degrees of freedom, which is used for the robot teleoperation with the force-feedback in the unknown environment. In this external structure mechanism, the 3-revolution-prismatic-spherical （3RPS） parallel mechanism is devised from the concept of the human upper-limb anatomy and applied for the shoulder 3-DOF joint. Meanwhile, the orthogonal experiment design method is introduced for its optimal design. Aiming at enhancing the performance of teleoperation, the force feedback is employed by the pneumatic system on ZJUESA to produce the vivid feeling in addition to the soft control interface. Due to the compressibility and nonlinearity of the pneumatic force feedback system, a novel hybrid fuzzy controller for the precise force control is proposed and realized based on the Mega8 microcontroller units as the units of the distributed control system on ZJUESA. With the results of several experiments for master-slave control with force feedback, the feasibility of ZJUESA system and the effect of its hybrid fuzzy controller are verified.     

Optimal actuator sizing and end point deformation for mobile robotic manipulators with elastic joint based on load criteria

Application of a numerical method to determine the maximum dynamic load carrying capacity (DLCC) for a robotic manipulator carrying an automobile petrol tank with joint elasticity subject to accuracy and actuator constraints is described in this paper. The maximum DLCC which can be achieved by a manipulator during a given trajectory is limited by a number of factors. The most important of which are the dynamic specification of the manipulator, the actuator limitations, and the elasticity of the joints such as reducers and servo drive system. Initially, the kinematic equations for carrying the automobile petrol tank by the robotic arm with 6 degrees of freedom (DOF) were calculated. The mechanical modeling was achieved via software programming. Dynamic modeling of the flexible joints manipulator was done simply for the three major axes. A method for determination of the dynamic load capacity with specific reference to both accuracy and actuator constraints is explained. The results obtained indicate the importance of both constraints and which constraint is more critical for accuracy and tracking.     

关节型机器人示教机构平衡设计与优化

针对示教机构并不应用于实际的生产中,而且不用考虑机构运动过程中的弹性变形、惯性力等性能,设计出了结构简单的轻质连杆来代替实际机器人的各构件。示教机构的设计原则是保留实际机器人的自由度数、机构尺寸和工作空间,其余部分进行简化。利用弹簧平衡法和增加端面对关节型机器人臂杆进行重力平衡,各关节无驱动电机和减速器,仅有编码器测量关节角度,在结构上用简单结构的轻质连杆连接于各关节之间。     

一种被动三自由度变刚度柔性基座设计

在一些大型航天器上,为扩大机械臂的工作空间,往往采用宏微臂组合的方式。当微臂工作时,宏臂相当于微臂的柔性基座。针对这种宏微臂串联组合方式,设计一种被动三自由度来模拟宏臂,用于微臂的地面试验。柔性基座实现了三自由度之间的耦合,且采用不同的原理实现了三自由度方向刚度的可调性。对柔性基座进行了刚度特性分析,得到了其变形角度的刚度阵,并对其刚度阵进行了分析。为柔性基座机械臂的动力学研究提供了实验平台。     

火车煤采样机多自由度机械臂运动轨迹控制研究

通过对火车煤采样机多自由度机械臂的结构分析和运动分析,建立了机械臂的运动方程式,并根据运动反求原理建立了再现轨迹的运动控制模型.为了得到多自由度机械臂可行的最优驱动曲线,提出了一套用优化设计方法求解的方案,从而解决了运动轨迹控制智能化问题.该方法可以广泛应用于关节型机械手的智能运动控制,具有较大的推广价值.     

一种面向航天需求的仿生柔性机械臂的设计

针对航天器舱内环境的障避实际需求,基于自然界象鼻的内部肌肉结构分布特点,设计一种多冗余自由度仿生柔性机械臂。该机械臂由8个柔性关节组成,每个柔性关节具有3个自由度,相比传统机械臂,具有结构紧凑、刚度较高、运动灵活、操作空间广泛等特点。针对所提出的单个柔性关节与多个关节组成的仿生柔性机械臂进行运动学建模分析。利用制作的仿生柔性机械臂,进行航天避障任务试验,验证了该机械臂结构的可行性。     

差速器在可变模式驱动系统中应用的可行性研究

为了发挥独立车轮驱动系统的优点并回避其结构缺陷,设计了一种双电机可变模式驱动系统,并对驱动系统中差速器这一关键部件的工作特性进行了理论分析和仿真验证。研究表明,差速器作为一个二自由度机构,除在集中驱动模式下起到差速作用外,在独立车轮驱动模式下,当取消对壳体的约束时,还可以保证两侧半轴齿轮的独立运动。因此,将差速器用于可变模式驱动系统中完全可行。     

闭式行星传动效率的计算

用单自由度齿轮传动去封双自由度差动齿轮传动机构的两个基本构件 (转臂和大中心轮 ,转臂和小中心轮 ) ,均可实现高效率地传递大转矩。文章采用新的方法对其效率计算公式作详细的综合分析 ,使其公式简单、适用。     

基于图论的三构态助老变胞机构的设计与运动学分析

为了研发一款助老机器人,基于图论理论、机构的数综合,设计了一种可在2自由度、1自由度、0自由度之间切换的三构态助老变胞机构。针对变胞机构的2自由度行走构态,运用闭环矢量法进行了运动学分析,得到该变胞机构在该构态下关键位置的位移、速度、加速度等变化规律。分析结果显示,位移曲线在支撑期过渡到摆动期时位移变化较大,在步态周期的后40%内,速度、加速度均有较大变化,符合人体步态规律,表明该助老变胞机构设计是合理的。     

The design of a five-degree-of-freedom powered orthosis for the upper limb.

In response to the need for a sophisticated powered upper-limb orthosis for use by people with disabilities and/or limb weakness or injury, the MULOS (motorized upper-limb orthotic system) has been developed. This is a five-degree-of-freedom electrically powered device having three degrees of freedom at the shoulder, one at the elbow and one to provide pronation/supination. The shoulder mechanism consists of a serial linkage having an equivalent centre of rotation close to that of the anatomical shoulder; this is a self-contained module in which power transmission is provided by tensioned cables. The elbow and pronation/supination modules are also self-contained. The system has been designed to operate under three modes of control: 1. As an assistive robot attached directly to the arm to provide controlled movements for people with severe disability. In this case, it can be operated by a variety of control interfaces, including a specially designed five-degree-of-freedom joystick. 2. Continuous passive motion for the therapy of joints after injury. The trajectory of the joints is selected by 'walk-through' programming and can be replayed for a given number of cycles at a chosen speed. 3. As an exercise device to provide strengthening exercises for elderly people or those recovering from injury or surgery. This mode has not been fully implemented at this stage. In assistive mode, prototype testing has demonstrated that the system can provide the movements required for a range of simple tasks and, in continuous passive motion (CPM) mode, the programming system has been successfully implemented. Great attention has been paid to all aspects of safety. Future work is required to identify problems of operation, and to develop new control interfaces.     

四自由度作业装置系统横向推拉力特性分析

针对步行式挖掘机的步行能力问题,利用Denavit-Hatenberg齐次变换矩阵建立了四自由度作业装置系统的运动学模型,以确定多节臂作业装置相对于基坐标系的函数关系,根据作业装置各个机构之间的连接关系和不同的驱动方式,分别建立了四自由度作业装置系统的横向最大推力和最大拉力的线性规划优化模型,利用序列二次规划算法求解该优化模型,得到了作业装置在工作空间内的最大横向推拉力的特性分布图。     

Self-locking analysis in closed kinematic chains

Self-locking analysis in closed kinematic chains is sometimes likened to kinematic singularity analysis, especially when mechanisms are characterized by more than one degree of freedom. Although in singular configurations a mechanism is obviously locked-up since joint constraint reactions and friction forces rise to infinity, this approach identifies only a condition sufficient for self-locking, while the phenomenon actually occurs in a larger domain, the size of which depends on the values of friction coefficients.The paper proposes a definition of self-locking for multi degrees of freedom mechanisms and presents an algorithm for computing the geometrical locus that corresponds to a specific self-locking configuration. This methodology is then demonstrated on a simple parallel kinematic mechanism with two degrees of freedom.     

Drive system design and error analysis of the 6 degrees of freedom segment erector of shield tunneling machine

Focusing on a segment erector of a shield-tunneling machine developed with 6 degrees of freedom (DOF) and controlled by electro-hydraulic proportional systems, the kinematics of the segment erection process is presented. The perturbation method in the error analysis is introduced to establish the position and attitude error model, considering a number of factors such as the hydraulic drive, control accuracy, and tolerance in manufacturing and assembly. Dynamic simulations are carried out to obtain the controlling precision of electrohydraulic drive systems. Formulas for calculating the position and attitude error of the grip hand of the segment erector are derived. The calculation results verify the practicality and effectiveness of the error analysis, providing a foundation for practical designing, manufacturing, and assembling of the segment of the erecting mechanism.     

2-UPU-RRC并联机构及奇异位形分析

提出一种新型三平移三自由度空间并联机器人机构,进行机构运动输出特性分析及自由度计算,并建立2-UPU-RRC并联机器人机构的位置正、反解方程。得到该机构的奇异位形。该机构解耦性好,为系统控制提供了方便。