上肢康复外骨骼重力平衡特性研究

为了辅助偏瘫患者进行上肢运动功能康复训练,研制了一种具有重力平衡特性的上肢康复外骨骼机器人系统.首先介绍了外骨骼的机械结构设计以及基于Matlab/RTW环境的半物理实时控制平台.然后基于辅助平衡法建立了系统重力平衡模型,通过添加零初始长度弹簧以及辅助连杆来平衡外骨骼和人体手臂在康复训练过程中受到的重力.最后通过仿真和实验,比较不同平衡条件下所需要施加的关节驱动力矩和肱二头肌的表面肌电信号强度.在仿真中,重力平衡状态下的平均关节驱动力矩为非重力平衡状态下的14.89%.在两种不同任务的实验中,重力平衡状态下的表面肌电信号强度分别为非重力平衡状态下的57.61%和63.49%.结果表明,实现外骨骼的重力平衡可以有效减小工作过程中的驱动力矩以及能量消耗,并降低对驱动设备的性能要求.     

柔性双轮平衡机器人的动力学建模与分析

提出了一种柔性双轮平衡机器人,其机身具有以一段弹簧作为弹性阻尼的被动俯仰旋转关节．运用拉 格朗日方法建立了此机器人在平面运动的动力学模型．基于此模型,首先证明了柔性双轮平衡机器人在直立平衡点 不稳定和局部可控．其次,分析了关节刚度对线性二次型最优姿态平衡控制系统的影响．结果显示,关节刚度减小 在理论上能够加强系统的鲁棒性,却使得控制系统动态性能下降．本文提出的模型及相关分析为柔性双轮平衡机器 人的设计和控制提供了一定理论依据．     

六自由度并联机器人的支链选取

提出了六自由度并联机器人的支链选取的系统方法． 并联机器人中有多种类型的支链可以用来实现末端执行器的6自由度运动， 每个支链的驱动关节应当在基座上或靠近基座的地方， 由支链所构成的整个并联机构的自由度应当为6．利用这些条件对并联机器人的支链形式进行筛选可以获得可行的支链形式． 通过这种方法可以去除很多不可行的支链形式, 得到可行的支链形式供后续设计使用．     

基于绳索牵引的航天员机能训练机器人虚拟重力控制

为了解决在微重力条件下长期生活的航天员的运动机能下降、肌肉萎缩和肌力衰退等问题,提出了一 种基于绳索牵引的柔性Stewart 式航天员机能训练机器人机构模型．在对机器人系统进行力学分析的基础上,提出 了一种基于单绳索力闭环的准闭环虚拟重力控制策略,并在实验样机上进行了虚拟重力控制模拟实验．研究结果表 明,该控制策略是可行的,可以在人体运动过程中实现虚拟重力加载控制．该研究为在微重力环境下通过机器人实 现虚拟重力加载控制奠定了理论基础．     

具有7自由度和双球型髋关节的仿人机器人下肢运动分析与规划

提出了具有7自由度和双球型髋关节的仿人机器人下肢机构．它和传统的6自由度双足步行机构相比，具有下述两大优点．首先双球型髋关节使机器人在不增加腰部关节的情况下实现腰部的基本运动功能，使机器人能够直立行走；其次在给定腰和足部位置时，它也能和人类一样实现转动双腿的动作．本文还对该复杂机构进行了运动特性分析、运动学求解、运动规划和实验验证．     

面向足式机器人的新型可调刚度柔性关节的设计及性能测试

为提高足式机器人的运动适应能力,为其设计了一款具有刚度连续调节功能的新型柔性旋转关节.通过研究杠杆机构输出刚度与传动比的对应关系,提出以变传动比杠杆机构作为核心部件进行可调刚度柔性关节的设计.文中对关节的结构以及关节驱动方式等进行了紧凑化设计,以满足足式机器人系统对体积及重量的要求.在设计中通过分析关节输出刚度系数与关节相关结构参数之间的关系,为关节输出刚度调节选择了较为敏感的参数调节范围,提高了刚度调节的灵敏性.在此基础上,通过开展机构运动学分析,确定了关节机构的理论刚度输出固有特性.关节样机测试表明,该调节机构能够实现关节输出刚度的调整和有效控制,该关节在结构设计以及功能方面均可以满足在足式机器人腿部结构中的应用需求.     

四足机器人前小腿系弹性牵拉驱动机构设计

为实现四足机器人腿机构轻量、柔性以及高刚度的设计,从生物学出发,研究了狗在高速运动中肌肉牵拉对其前腿骨骼刚度的影响.应用ADAMS动力学仿真软件模拟了狗单条腿在对角步态下的运动与受力环境,研究并比较了骨骼受肌肉牵拉和无肌肉牵拉两种状态.仿真结果证明,肌肉牵拉对骨骼刚度有大幅度的增强作用,能够使骨骼支撑动物实现稳定的运动而不被破坏.进一步提出并验证了采用弹簧弹性力牵拉能够达到与肌肉牵拉力相同的效果,并将此结论应用于四足机器人前小腿弹性牵拉驱动机构设计中,将关节弹性力耦合作用与机构两端形成牵拉作用,并研究了弹性力作用点变化与弹簧刚度以及机构最大应力值之间的约束关系.结果表明,这种设计在保证关节弹性力输出控制特性不受影响的情况下能够有效提高腿机构的刚度.     

一种仿虎甲幼虫的多驱动器软体机器人的设计与制造

设计和制造了一种多驱动器软体机器人来模拟虎甲幼虫的爬行、转向和咬合运动．其中,软体机器人尾部采用多气囊式软体驱动器,实现了向前运动;软体机器人颈部采用纤维增强弯曲致动器,实现了转向运动;软体机器人头部采用形状记忆合金（SMA）弹簧驱动,实现了咬合运动．最后,模拟虎甲幼虫爬行捕捉小红果进行了实验,结果证明该软体机器人的多驱动器设计可以模拟虎甲幼虫进行复杂运动．     

机器人串联弹性关节驱动器的刚度控制方法

机器人关节的柔顺性在人机协作过程中具有重要作用，然而固定的关节柔性无法满足动态变化的人机协作需求，因此对机器人的关节驱动器提出了具有刚度调节能力的要求.本文采用阿基米德螺旋线平面涡卷弹簧作为机器人关节的柔性元件，并提出一种可用于具有固定刚度的串联弹性驱动器的刚度控制方法.根据关节刚度的定义，将测量得到的弹簧输出端角度用于计算弹簧的输入端转角，使得机器人关节驱动器的等效刚度可以被调整到所期望的大小.该方法以电机位置控制为内环，关节刚度控制为外环，简化了控制器设计，并实现了解耦控制.对所设计的刚度控制器进行了分析.最后在自主设计的单自由度薄型串联弹性驱动器实验平台上进行了刚度调节实验，包括刚度的双向阶跃、零刚度和正弦变化的刚度，实验结果表明关节等效刚度能准确跟踪期望值，验证了该方法的有效性.     

仿人型跑步机器人矢状面跑步运动的实现

基于“虚拟腿”的概念,提出了一种新的方法实现仿人型跑步机器人在矢状面内的跑步运动．首先,规划机器人质心的轨迹; 在起跳阶段通过求解“虚拟腿”的二自由度动力学方程,规划机器人质心的轨迹;在飞行阶段机器人质心做自由落体运动．然后,对机器人双脚的运动和上臂的运动进行规划,采用牛顿—拉斐逊法求解非线性方程组得到机器人在每个时刻的运动学参数．最后,根据动力学方程求出各个关节的驱动力矩．仿真实验结果表明：机器人跑步时各个关节角度和关节驱动力矩变化平稳,运动稳定裕度大,机器人可以实现1.2m/s的跑步速度,因此机器人的跑步动作设计合理．     

基于Kinect的仿人机器人控制系统

为实现对具有16个自由度仿人机器人的姿态控制,采用Kinect传感器对人体姿态的坐标数据进行采集,根据坐标信息利用Processing软件开发基于SimpleOpenNI库的上位机软件,建立人体关节模型,并利用空间向量法对仿人机器人的步态规划以及重心控制算法分析,解析各关节的转动角度,经由无线WiFi模块向仿人机器人发送指令以控制舵机的运动,最终实现对机器人的控制,搭建了基于Kinect传感器的测试平台.测试结果表明:仿人机器人上肢在运动范围内无死角,通过对重心的控制,下肢可实现简单的步行,符合预期效果.     

Gravity compensation of spatial two‐DOF serial manipulators

This article presents the analysis of gravity compensation of a two‐DOF serial manipulator operating in three‐dimensional space by means of linear spring suspension. The physical configuration of the serial manipulator is assumed general. The analysis begins with gravity compensation of a one‐DOF manipulator in order to form the basis which is then extended to a two‐DOF manipulator. The approach taken in the analysis is that of conservation of potential energy. The goal is to seek the location and the stiffness of springs that provide complete compensation of gravity in the manipulator system. It has been found that complete compensation of gravity in a two‐DOF serial manipulator system is possible. Unlike many previous works on spring suspension of a rigid body, which assume that one end of the suspending spring is attached to ground, it is proven in this study that, for complete compensation in a two‐DOF manipulator, the spring that suspends the distal link cannot be connected to ground. Instead, it must be in certain motion relative to the proximal link. The discussion on how to provide such a motion for the spring is given. It is also explained how the problem of gravity compensation of a robot manipulator can be shifted to that of changing gravity environment within a manipulator system. The concept can be applied to simulation and testing of robot manipulators that will be sent to operate in a different gravity environment, such as space. © 2002 Wiley Periodicals, Inc.     

Shadow robot for teaching motion

Human-friendly robots have begun to spread in society. In the future such robots and intelligent machines should be autonomous in open situations. To give dexterity to a robot, teaching motion is a good candidate. However, there are some problems from the operational point of view due to gravity and friction effects.In this paper, a shadow robot is proposed for teaching motion instead of force sensors. The shadow robot is a novel disturbance compensation method that consists of a twin robot system. Two of the same type of robot are required and they are controlled with the same position, velocity, and acceleration by bilateral acceleration control based on a disturbance observer. One robot is in the teaching motion controlled by a human and the other is unconstrained. Thus the purity of the human force is extracted by subtracting the disturbance torque in the unconstrained robot from the constrained one. As a result, the shadow robot observes the human force with gravity and friction compensation. Since it is possible to apply this concept to a multi-degree-of-freedom system, the human operationality in teaching motion are improved.The experimental results show the viability of the proposed method.     

Gravity compensation in robotics

The actuator power required to resist joint torque caused by the weight of robot links can be a significant problem. Gravity compensation is a well-known technique in robot design to achieve equilibrium throughout the range of motion and as a result to reduce the loads on the actuator. Therefore, it is desirable and commonly implemented in many situations. Various design concepts for gravity compensation are available in the literature. This paper proposes an overview of gravity compensation methods applied in robotics. The examined properties of the gravity compensation are disclosed and illustrated via kinematic schemes. In order to classify the considered balancing schemes three principal groups are distinguished due to the nature of the compensation force: counterweight, spring or active force developed by an auxiliary actuator. Then, each group is reviewed through sub-groups organized via structural features of balancing schemes. The author believes that such an arrangement of gravity compensation methods allows one to carry out a systematized analysis and provides a comprehensive view on the problem.     

Trajectory generation and control for a biped robot walking upstairs

This paper presents an effective and systematic trajectory generation method, together with a control method for enabling a biped robot to walk upstairs. The COG (center of gravity) trajectory is generated by the VHIPM (virtual height inverted pendulum mode) for the horizontal motion and by a 6th order polynomial for the vertical motion; an ankle compliance control (ACC) is also added into the robot control. The proposed methods are evaluated by simulations as well as being implemented in a robot for the performance verification. The results show that the proposed methods can generate stable motions when walking upstairs, and these can significantly reduce the zero moment point (ZMP) errors compared with other methods, enabling the robot to walk up steeper stairs.     

Synthesis and analysis of a flexible elephant trunk robot

This paper presents a novel synthesis and analysis of a flexible elephant trunk robot (biological continuum–style manipulator). The robot includes eight flexible segments, although it can be extended to more segments as necessary. In this study the gravity of the springs is neglected due to the fact that the manipulation force is much larger than these gravity forces. This mechanism exhibits a wide range of maneuverability and has a large number of degrees of freedom. Each segment is designed using a novel flexible mechanism based on the loading of a compression spring in both transverse and axial directions, and using cable–conduit systems. The rotational motion is transformed to tendon-like behavior, which enables the location of the actuators away from the trunk (e.g. at the end of the trunk). The forward kinematics of the mechanism is also presented and lends itself well to computer control. It is shown that the solution of the transverse deflection of each segment is obtained in a general form, while the stiffness coefficients are obtained in closed form from a two-dimensional model (small and large deflection angles) and from a three-dimensional model used in a finite element method to verify results. The friction in the analysis between the cable and the conduit is neglected in the analysis. A prototype trunk segment is experimentally tested, the results are verified and the elephant trunk robot is built. A bench-top actuation system has been developed and a control scheme used in prosthetic hand control has been implemented to control the mechanism.     

基于LabVIEW的机器人的运动控制系统研究

为了减少机器人运动轨迹误差,实现对机器人的精准控制,提高机器人的运动效率,设计了基于LabVIEW的机器人的运动控制系统;采用了NI公司的控制板卡,选用了Odriver驱动器作为主控制器,选用大力矩伺服电机作为驱动电机,实现运动控制系统的硬件架构的设计;通过脉冲信号驱动电机运动,获取机器人的运动轨迹数据,通过进行对控制...     

空间机械臂地面竖直方向重力补偿控制系统设计

为解决大型空间机械臂地面微重力模拟实验问题,设计了一种3维主动悬吊式重力补偿系统.系统主要由水平2维直线运动单元与竖直重力平衡吊挂单元组成,在竖直方向上通过恒张力控制思想实现微重力模拟,并给出了带负载的伺服电机的数学模型.提出一种基于模糊PID(比例―积分―微分)参数整定的力/位混合控制方法,并研究了在未知负载干扰、系统干扰以及机械臂不同运动速度下控制器的控制性能.仿真实验结果表明,该控制方法能够将重力补偿精度保持在0.3%F.S(全量程)之内,使得系统具有较强的鲁棒性和动态响应能力.     

Inverse Kinematics and Workspace Analysis of a 3 DOF Flexible Parallel Humanoid Neck Robot

To mimic the human neck’s three degree-of-freedom (DOF) rotation motion, we present a novel bio-inspired cable driven parallel robot with a flexible spine. Although there exists many parallel robotic platform that can mimic the human neck motion, most of them have only two DOF, with the yaw motion being actuated separately. The presented flexible parallel humanoid neck robot employs a column compression spring as the main body of cervical vertebra and four cables as neck muscles to connect the base and moving platform. The pitch and roll movements of moving platform are realized by the two dimensional lateral bending motion of the flexible spring, and a bearing located at the top of the compression spring and embedded in the moving platform is used to achieve the yaw motion of the moving platform. By combing the force and torque balance equations with the lateral bending statics of the spring, inverse kinematics and optimizing the cable placements to minimize the actuating cable force are investigated. Moreover, the translational workspace corresponding to pitch and roll movements and rotational workspace corresponding to yaw movement are analyzed with positive cable tension constraint. Extensive simulations were performed and demonstrated the feasibility and effectiveness of the proposed inverse kinematics and workspace analysis of the novel 3 DOF flexible parallel humanoid neck robot.     

遥操作护理机器人系统的操作者姿态解算方法研究

设计了一种遥操作护理机器人系统,为实现从端同构式机器人的随动运动控制,对主端操作者人体姿态解算方法进行了研究.首先,构建由惯性传感单元构成的动作捕捉系统,对用作从端机器人动作指令的操作者人体姿态信息进行采集,采用四元数法对人体运动原始数据进行初步求解.其次,将四元数法得到的姿态数据解算成依据仿人结构设计的护理机器人各关节运动的目标姿态角,实现人体姿态到机器人动作的同构性映射.最后,为验证本文所提姿态解算方法的性能,设计了操作者控制护理机器人完成递送和拿取药瓶动作的实验.结果表明,本文姿态解算方法的解算性能与参考系统基本相同;在操作者动作姿态快速变化的时间段,系统仍可获得较高精度的目标姿态数据,其误差在动态条件下依旧能保持在2%以下;护理机器人可较好地实时复现操作者的人体动作.本文方法能满足机器人进行一般护理作业时对人体姿态数据处理的快速性和准确性要求.