Dynamics Modeling and Robust Trajectory Tracking Control for a Class of Hybrid Humanoid Arm Based on Neural Network

In order to solve the problem of trajectory tracking for a class of novel serial-parallel hybrid humanoid arm（HHA）, which has parameters uncertainty, frictions, disturbance, abrasion and pulse forces derived from motors, a multistep dynamics modeling strategy is proposed and a robust controller based on neural network（NN）-adaptive algorithm is designed. At the first step of dynamics modeling, the dynamics model of the reduced HHA is established by Lagrange method. At the second step of dynamics modeling, the parameter uncertain part resulting mainly from the idealization of the HHA is learned by adaptive algorithm. In the trajectory tracking controller, the radial basis function（RBF） NN, whose optimal weights are learned online by adaptive algorithm, is used to learn the upper limit function of the total uncertainties including frictions, disturbances, abrasion and pulse forces. To a great extent, the conservatism of this robust trajectory tracking controller is reduced, and by this controller the HHA can impersonate mostly human actions. The proof and simulation results testify the validity of the adaptive strategy for parameter learning and the neural network-adaptive strategy for the trajectory tracking control.

A modular cable-driven humanoid arm with anti-parallelogram mechanisms and Bowden cables

This paper proposes a novel modular cable-driven humanoid arm with anti-parallelogram mechanisms(APMs)and Bowden cables.The lightweight arm realizes the advantage of joint independence and the rational layout of the driving units on the base.First,this paper analyzes the kinematic performance of the APM and uses the rolling motion between two ellipses to approximate a pure-circular-rolling motion.Then,a novel type of one-degree-of-freedom(1-DOF)elbow joint is proposed based on this principle,which is also applied to design the 3-DOF wrist and shoulder joints.Next,Bowden cables are used to connect the joints and their driving units to obtain a modular cable-driven arm with excellent joint independence.After that,both the forward and inverse kinematics of the entire arm are analyzed.Last,a humanoid arm prototype was developed,and the assembly velocity,joint motion performance,joint stiffness,load carrying,typical humanoid arm movements,and repeatability were tested to verify the arm performance.

Resonance Suppression Strategy for Humanoid Robot Arm

To address the problem of resonance in the control of a robot arm,a resonance suppression strategy is proposed for a single-joint humanoid robot arm based on the proportionalresonant(PR)controller.First,an arm joint model of the humanoid robot is established.Then the influence of resonance frequency on the performance of the control system with the robot arm is analyzed.The voltage fluctuation of the drive motor caused by the changes in arm motion is recognized as the disturbance of the current loop.The PR controller has the characteristic of disturbance rejection at a specific frequency.The output fluctuation of the driving system caused by the change of arm motion state at the resonance frequency is suppressed.Therefore the output current of the inverter will not be affected by the vibration of the arm at the resonance frequency.Finally,the control system is verified by MATLAB/Simulink simulation.The simulation results demonstrate that the control strategy for the humanoid robot arm based on the PR controller can suppress the resonance of the arm effectively,improving the dynamic performance and system stability.

Similarity comprehensive evaluation of humanoid robot arm motion

A suitable comprehensive evaluation method for similarity comprehensive evaluation of humanoid motion(mainly to robotic arm) is proposed.For different robotic arms, a static comprehensive evaluation model is established by projection pursuit evaluation based on indexes of humanoid robot arm motion in robotics and ergonomics field. Based on projection pursuit evaluation with timing information entropy and time degrees, a dynamic comprehensive evaluation method is proposed by linear weighting to each time's static model's indexes weight according to timing weighted vectors. Through comparing similarity comprehensive evaluation result based on static and dynamic comprehensive evaluation model, the results show that similarity based on dynamic comprehensive evaluation model is high. By comparing reliability, similarity and dispersion of static and dynamic comprehensive evaluation models, the results show that dynamic comprehensive evaluation result has better accuracy, stability and lower dispersion, and the result is more reasonable and real. Therefore, the dynamic comprehensive evaluation method proposed in this paper is more suitable for similarity comprehensive evaluation of humanoid robot arm motion.

Bio-inspired Design and Inverse Kinematics Solution of an Omnidirectional Humanoid Robotic Arm with Geometric and Load Capacity Constraints

Inspired by the driving muscles of the human arm,a 4-Degree of Freedom(DOF)concentrated driving humanoid robotic arm is proposed based on a spatial double parallel four-bar mechanism.The four-bar mechanism design reduces the inertia of the elbow-driving unit and the torque by 76.65%and 57.81%,respectively.Mimicking the human pose regulation strategy that the human arm picks up a heavy object by adjusting its posture naturally without complicated control,the robotic arm features an integrated position-level closed-form inverse solution method considering both geometric and load capacity limitations.This method consists of a geometric constraint model incorporating the arm angle(φ)and the Global Configuration(GC)to avoid joint limits and singularities,and a load capacity model to constrain the feasible domain of the arm angle.Further,trajectory tracking simulations and experiments are conducted to validate the feasibility of the proposed inverse solution method.The simulated maximum output torque,maximum output power and total energy consumption of the robotic arm are reduced by up to 2.0%,13.3%,and 33.3%,respectively.The experimental results demonstrate that the robotic arm can bear heavy loads in a human-like posture,effectively reducing the maximum output torque and energy consumption of the robotic arm by 1.83%and 5.03%,respectively,while avoiding joints beyond geometric and load capacity limitations.The proposed design provides a high payload–weight ratio and an efficient pose control solution for robotic arms,which can potentially broaden the application spectrum of humanoid robots.

基于ARM的类人足球机器人视觉识别系统的设计

针对类人足球机器人在复杂赛场环境中对目标色块识别能力的不足,设计一种基于ARM的类人足球机器人视觉识别系统。软硬件设计上,以搭载Linux系统的三星S3C6410作为主控图像处理芯片,用飞思卡尔MC9S12XS128单片机作为舵机控制器,以罗技C270摄像头作为视觉传感器。分割识别算法上,采用YUV颜色空间下的阈值法与区域生长的混合分割算法对色块信息进行快速分割和识别。实验表明,该设计可准确识别出较复杂环境中的目标色块并定位出中心坐标。

基于ARM的仿人机器人及其控制平台研究

通过建模构建满足机械结构的空间移动范围,使仿人机器人具备演奏小提琴的可能性。控制系统采用集中管理分散控制的方式,以ARM10为控制核心,将控制系统各个控制部分模块化,基于ARM核心智能控制配合传感反馈系统完成对机器人的行为控制,完成了在人工辅助下可演奏完整曲目的机器人。

Kinect-Based Humanoid Robotic Manipulator for Human Upper Limbs Movements Tracking

This paper presents a humanoid robotic arms controlled by tracking the human skeleton movement in real-time using Kinect upper limbbody tracking. Using Kinect tracking algorithm, the positions of upper limb arms of the body to the wrist in 3D space can be estimated by processing depth images from the Kinect. An extraction of 3D co-ordinates of the user’s both arm in real-time then Arduino microcontroller is transferring the data between both of computer and the humanoid robotic arm. This method provides a way to send movement task to the humanoid robotic manipulator instead of sending the end position motion like gesture-based approaches and this method has been tested in detect, tracking and following the movement of human skeleton gesture. Designing complete prototype of a humanoid robotic arms with 4DOF three joints in shoulder and one elbow joint to the wrist that look like the Human arm Structure, Appearance and Action that represent human arm movement performed by the humanoid robotic arm. The error was and response time result generated is small (less than 4.6% and 105 ms).

轻型仿人机械手臂集成研发平台ArmPlant的设计与实现

建立了一个轻型仿人机械手臂集成研发平台ArmPlant,该平台基于ODE物理引擎计算,采用Visual C++、Matlab混合编程开发,集外形尺寸设计、质量分布、关节扭矩评测、运动学及逆运动学计算、动作规划与仿真、人体动作采集和再现、运动控制、样机硬件驱动、运动特性评测等功能于一体,可用于仿人机械手臂的快速研制过程。实践过程中,基于该平台设计并实现一款8-DoF仿人机械手臂,并选取物体连续抓取、人体动作跟踪再现这两个场景,对ArmPlant整体功能及机械手臂运动特性进行评测。仿真实验及样机实验均表明ArmPlant功能较完备、计算及控制准确、交互性强,能有效支持轻型仿人机械手臂的研发全过程,显著提高研发效率。

7自由度仿人机械臂工作空间求解的降密蒙特卡洛法

针对蒙特卡洛法和改进蒙特卡洛法在求解机械臂工作空间时存在精度不够准确和加密点云浪费的问题,提出一种降密蒙特卡洛法.首先,基于蒙特卡洛法中随机点分布不均的特性,对机械臂初始工作空间进行均匀加密,使空间的内部与边界区域分明;然后,采用扩展关节角度和循环加密随机点的方式,只对边界区域进行加密,达到降低工作空间随机点云密度的目的;同时,还研究了该方法中初始点云数量、各轴向分割体素数量、精度阈值、扩展关节角度和循环次数等参数对工作空间精度的影响;最后,通过仿真分析对降密蒙特卡洛法的有效性进行验证.结果表明:相比于蒙特卡洛法,降密蒙特卡洛法在工作空间平均误差率为0.022 42%时,总随机点云数量降幅为93.89%;相比于改进蒙特卡洛法,在循环次数为2次和4次时,降密蒙特卡洛法工作空间的平均误差率分别降低0.138 53%和0.113 29%,总随机点云数量降幅分别为44.83%和64.52%.

多电机耦合驱动式仿人机械臂设计与传动特性分析

针对传统仿人机械臂载荷与自重比低的问题,提出一种多电机耦合驱动式仿人机械臂。根据人臂的运动特性,确定串联结构下的仿人机械臂构型,并将机械臂划分为肩关节模块、肘关节模块和腕关节模块。分析单电机驱动单关节的绳索传动特性,推导该模型下电机与关节的扭矩映射关系和转角映射关系。研究各模块中多电机耦合驱动多关节的电机布局和绳索绕线方式,解释各模块中多电机耦合后的工作原理,推导各模块中电机与关节的扭矩映射关系和转角映射关系。并通过实验验证各模块中映射关系的正确性,以及各模块关节的承载能力。结果表明:多电机耦合驱动方式在保证质量的前提下,可以有效提高各关节的承载力,为仿人机械臂的设计提供理论依据。

人形竞赛机器人机械手臂设计与运动学分析

以人形竞赛机器人机械手臂设计出发,首先分析机械手臂的功能与动作情况、以及人类手臂关节构成,据此设计3自由度人形竞赛机器人机械手臂;第二,采用D-H方法,从结构的角度简化坐标系建立的方式,确定D-H参数,分析得出机械手臂的正运动学方程;第三是采用几何方法与解析求解法相结合的方式进行逆运动学求解;最后,在MATLAB平台中采用蒙特卡洛方法分析机械手臂的工作空间验证求解结果,结果显示设计的机械手臂满足竞赛的工作空间要求。

基于人体工程学的仿人机械臂构型

针对仿人机械臂构型问题,提出一种新的筛选方法,并确定串联结构方式下最符合人臂特征的仿人机械臂构型。从人体解剖学的角度出发,分析人臂的运动机理,并结合人体测量学和机器人学相关原理构建6种不同的仿人机械臂构型。提出全局相对可操作度指标对不同构型进行灵活性分析,并采用可视化方法绘制出各构型的运动灵活性性能分布图。根据人臂的运动特性分析人臂的运动工作空间,将各构型仿人机械臂工作空间与其对比,从而筛选出串联方式下的最佳仿人机械臂构型。该结果为仿人机械臂的设计提供了理论依据,并为后续运动规划奠定了基础。

绳驱动拟人臂机器人的动力学建模及张力分析

与传统的机械臂相比,绳驱动拟人臂机器人采用串并混联的结构形式,模拟了人手臂肌肉的并联驱动方式,但是,绳索的引入也增加了动力学分析的难度.将绳驱动拟人臂机器人视为基座、大臂、小臂和末端四连杆串联机构,采用迭代牛顿-欧拉法建立动力学方程的递推形式,考虑绳驱动的冗余特性和绳索的单方向受力性,提出基于动态最小预紧力的张力分配算法,求解出各绳索的驱动力.与未进行张力分配的方法及基于静态最小预紧力的方法相比,所提出的算法可使各绳索驱动力根据动态最小预紧力进行实时调节,满足了不同工作条件下机构的刚度要求.

全局和声搜索方法及其在仿人灵巧臂逆运动学求解中的应用

仿人灵巧臂逆运动学(IK)问题可转化为等效的最小化问题,并采用数值优化方法求解.和声搜索(HS)是模拟乐师在音乐演奏中调整音调现象的一种启发式搜索方法,目前还尚未在机器人机械臂逆运动学问题中得到应用.本文提出一种基于粒子群体智能的全局和声搜索方法(GHSA),该方法在和声搜索算法中引入微粒群操作(PSO),采用粒子群策略替代常规和声搜索算法中的搜索法则创作新和声,通过粒子自身认知和群体知识更新和声变量位置信息平衡算法对解空间全局探索与局部开发间能力;同时算法还引入变异操作增强算法跳出局部最优解能力,基准函数测试表明该方法改善了全局搜索能力及求解可靠性.在此基础上以七自由度(7-DOF)冗余仿人灵巧臂为例,考虑以灵巧臂末端位姿误差和"舒适度"指标构建适应度函数并采用GHSA算法求解其逆运动学(IK)问题,数值仿真结果表明了该方法是解决仿人灵巧臂逆运动学问题的一种有效方法.

仿人按摩机器人手臂结构设计及改进

仿人按摩机器人手臂是以传统中医按摩理论为基础,结合机器人定位精度高,按摩力量精确可控,动作可准确重复,不会产生疲劳等特点,构建了中医按摩机器人平台。机器人手臂是仿人按摩机器人的关键,在深入研究按摩机器人手臂的工作机理基础上,充分考虑手臂的材料、结构和刚度以及手臂反应的灵活性、稳定性、安全性、拟人化等要求,对大臂、肩关节、肘关节、小臂、手腕等关键环节进行了设计及改进。经过性能对比分析,设计的仿人按摩机器人手臂达到设计要求。

新型七自由度拟人手臂位置反解及轨迹规划

提出了一种新型的7自由度手臂,3-RRR作为肩关节,两自由度球面机构Ur作为肘关节和腕关节,设计紧凑,可以提高承载力和灵活性。对手臂的运动学反解进行了分析,推导出拟人手臂的位置反解计算公式。利用虚拟样机技术对手臂期望轨迹进行了规划,得到驱动电机的转角运动轨迹。最后通过规划结果验证反解的正确性。

机器人航天员精细操作方法及在轨验证

针对航天员舱外活动风险与空间探索的效率问题,建立了具有双臂手的机器人航天员系统。该机器人航天员由多自由度机械臂、仿人灵巧手及具有双目视觉系统的头部等构成,具有位置、力矩、视觉等多种感知功能。为了验证机器人航天员及在轨人机协同关键技术,在空间微重力环境下与航天员配合完成多种演示验证试验,为空间机器人辅助或配合航天员开展在轨维修积累了经验和数据。

服务机器人拟人臂和底盘运动学建模

针对服务展示移动平台拟人手臂抓物体和移动问题,将其分为移动定位底盘和拟人抓取手臂两个基础部分。首先,构建了基于MDH法的连杆坐标系,其次从正、反运动学描述两个方面对拟人手臂进行了坐标系建模。再次把展示服务平台建模成驱动轮上的一个刚体,该服务展示平台移动定位底盘的总维数是三个:两个为移动平面中的位置信息;一个为垂直移动平面的旋量信息。最后,利用Open GL与VC6.0对四轴拟人手臂进行了仿真实验,验证了正、逆运动学求解工程的正确性。实验结果表明,该运动学建模能够反应出服务机器人真实运动情况。

达点臂姿预测指标与机械臂仿人运动

从弹性系数的影响因素出发,完善最小势能指标。基于大量试验,得到影响扭簧系数的因素为主观因素和客观因素。标准化客观因素,用聚类分析方法对主观因素分类,利用多元线性回归方法得到弹性系数与目标点之间的具体数学表达通式。用最小势能指标预测人臂达点臂姿,验证弹性系数,并与其他指标的预测结果对比。结果显示基于提出的弹性系数的最小势能指标能够准确预测更多人的臂姿。对机械臂进行仿人运动规划试验,证明最小势能指标的实用性。