Mechanism Design and Motion Analysis of Heavy⁃Load Transfer Robot with Parallel Four⁃Bar Mechanism

Heavy-load transfer robots are widely used in automobile production and machinery manufacturing to improve production efficiency.In order to meet the needs of large billet transfer,a 4-DOF transfer robot is designed in this paper,which consists of parallel four-bar mechanisms.The Jacobian matrix referring to the mapping matrix from the joint velocity to the operating space velocity of the transfer robot can be solved by the differential-vector method.The mean value of the Jacobian matrix condition number in the workspace is used as the global performance index of the robot velocity and the optimization goal.The constraint condition is established based on the actual working condition.Then the linkage length optimization is carried out to decrease the length of the linkage and to increase the global performance index of velocity.The total length of robot rods is reduced by 6.12%.The global performance index of velocity is improved by 45.15%.Taking the optimized rod length as the mechanism parameter,the distribution of the motion space of the transfer robot is obtained.Finally,the results show that the proposed method for establishing the Jacobian matrix of the lower-mobility robot and for the optimization of the rods based on the velocity global performance index is accurate and effective.The workspace distribution of the robot meets the design requirements.

RESEARCH ON TRANSFER MATRIX OF ROBOT WRIST FORCE SENSOR

The transfer matrix of wrist force sensor is important for decoupling theoutput signals and enhancing the precision of wrist force sensor.This paper solves thetransfer matrix from the realization of optimal approximation of polynomial.First,thegeneral transfer matrix algorithm in the sense of L^2 and two kinds of modified algorithmare proposed.Then,starting from uniform approximation,the optimal transfer matrixalgorithm is offered and solved by the use of linear programming.The results of experi-ment and computation prove that these algorithms are effective.

Resonant-Inductive Wireless Power Transfer for Autonomous Mobile Robots

Due to the increasing commercial interest in autonomy and sustainability,this paper reviews and presents a comprehensive summary of the resonant-inductive power transmission(RPT)technology for autonomous mobile robots.It outlines historic and recent research activities in wireless power transmission,covering the fundamental operation of microwave,capacitive and inductive power transfer technologies,state-of-the-art developments in RPT for high-power applications,current design and health standards,technological drawbacks,and possible future trends.In this paper,coupling-enhanced pad designs,adaptive tuning techniques,compensation network designs,and control techniques are explored.Major design issues such as coupling variation,frequency splitting,and bifurcation are reviewed.The difference between maximum power transfer and maximum energy efficiency is highlighted.Human exposure guidelines are summarized from documentations provided by the Institute of Electrical and Electronics Engineers(IEEE)and the International Commission on Non-ionizing Radiation Protection(ICNIRP).Other standards like WPC’s Qi and Airfuel design standards are also summarized.Finally,the possible trends of the relevant research and development,particularly dynamic charging,are discussed.The intention of this review is to encourage designs that will relieve robot operators of the burden of frequent manual recharging,and to reduce downtime and increase the productivity of autonomous mobile robots in industrial environments.

Gait Analysis of Quadruped Robot Using the Equivalent Mechanism Concept Based on Metamorphosis

The previous research regarding the gait planning of quadruped robot focuses on the sequence for lifting o and placing the feet, but neglects the influence of body height. However, body height a ects gait performance significantly, such as in terms of the stride length and stability margin. We herein study the performance of a quadruped robot using the equivalent mechanism concept based on metamorphosis. Assuming the constraints between standing feet and the ground with hinges, the ground, standing legs and robot body are considered as a parallel mechanism, and each swing leg is regarded as a typical serial manipulator. The equivalent mechanism varies while the robot moves on the ground. One gait cycle is divided into several periods, including step forward stages and switching stages. There exists a specific equivalent mechanism corresponding to each gait period. The robot's locomotion can be regarded as the motion of these series of equivalent mechanisms. The kinematics model and simplified model of the equivalent mechanism is established. A new definition of the multilegged robot stability margin, based on friction coe cient, is presented to evaluate the robot stability. The stable workspaces of the equivalent mechanism in the step forward stage of trotting gait under di erent friction coe cients are analyzed. The stride length of the robots is presented by analyzing the relationship between the stable workspaces of the equivalent mechanisms of two adjacent step forward stages in one gait cycle. The simulation results show that the stride length is larger with increasing friction coe cient. We herein propose a new method based on metamorphosis, and an equivalent mechanism to analyze the stability margin and stable workspace of the multilegged robot.

Influence of Data Clouds Fusion From 3D RealTime Vision System on Robotic Group Dead Reckoning in Unknown Terrain

This paper proposes the solution of tasks set required for autonomous robotic group behavior optimization during the mission on a distributed area in a cluttered hazardous terrain.The navigation scheme uses the benefits of the original real-time technical vision system(TVS)based on a dynamic triangulation principle.The method uses TVS output data with fuzzy logic rules processing for resolution stabilization.Based on previous researches,the dynamic communication network model is modified to implement the propagation of information with a feedback method for more stable data exchange inside the robotic group.According to the comparative analysis of approximation methods,in this paper authors are proposing to use two-steps post-processing path planning aiming to get a smooth and energy-saving trajectory.The article provides a wide range of studies and computational experiment results for different scenarios for evaluation of common cloud point influence on robotic motion planning.

Wireless Charger Design of Robot Vacuum Cleaners with Power Repeaters for High Compatibility

Curved coils constructed by flexible printed circuit board (PCB) or hand-wound Litz-wire have been steadily becoming popular due to its applicable potential on devices that have a curved body. Inductive Power Transfer (IPT) systems based on curved coils and flexible ferrite sheets may provide more flexible charging solutions for various electronic devices such as rice cookers and robot vacuum cleaners. Power repeaters are also used in IPT systems to extend wireless charging range by guiding magnetic fields to the receiving coil. The interaction of these three topics could be inspiring. In this paper, two adjustable power repeaters are applied to an IPT charging system with various curved receiving coils designed for vacuum cleaners. Two power repeaters share the identical structure as the Tx coil and could be rotated to mirror symmetrically. The input and output power are calculated by analyzing the equivalent circuit model. The self-inductance, mutual inductance, and coupling coefficient of the proposed system are obtained via finite element method simulation with variable rotating angles. Three typical IPT designs have also been simulated in ANSYS Maxwell and compared with the proposed magnetic design. The comparison indicates the enhancing feature of the passive power repeaters on coupling performance and the ability to guide the magnetic flux for better magnetic field coupling. Furthermore, two types of co-simulations defined by the power source via Simplorer are conducted to explore how much power could be transferred. The tuned system is shown to be able to provide about 32 W under 100 kHz operating frequency for charging the battery of a robot vacuum cleaner. The results from theoretical calculation and simulation align well with each other.

移乘背抱护理机器人舒适性生物力学模型分析

为探索移乘背抱护理机器人人机交互力学特性与被护理人舒适性感受的潜在关联,研究显性的人机接触力相对于人体生物力学特性的映射关系,揭示影响被护理人舒适性的主要作用肌群,提出了舒适性测试试验与AnyBody背抱运动人体生物力学模型相结合的方法.从被护理人的肌肉激活程度入手,对移乘背抱护理机器人背抱运动舒适性特征进行了分析.首先,介绍了移乘背抱护理机器人典型结构工作原理并进行了运动学分析,在此基础上搭建了舒适性测试试验系统,基于主观舒适性评分规划了服务于试验的基础运动轨迹,并通过试验得到了人机主要接触部位力学信息.然后,以试验数据为边界条件构建了基于AnyBody的背抱运动人体生物力学模型,依托逆动力学仿真分析得到了肌肉激活程度,并对比舒适性测试肌肉激活程度验证了仿真模型的有效性.最后,结合人机主要接触部位受力、肌肉激活程度及主观舒适性评分综合分析了移乘背抱护理机器人背抱运动舒适性特征,明确了影响被护理人舒适性的主要作用肌群.结果表明:影响被护理人舒适性的主要作用肌群有7个,且被护理人胸部压力与腋下压力值大小分别与影响其躯干和上肢舒适性的肌肉激活程度呈正相关.可通过建立胸部压力与腋下压力值相关的加权函数有效描述不同被护理人整体舒适性特征,为移乘背抱护理机器人舒适性运动控制提供了理论依据.

面向机器人系统的虚实迁移强化学习综述

近年来,基于环境交互的强化学习方法在机器人相关应用领域取得巨大成功,为机器人行为控制策略优化提供一个现实可行的解决方案.但在真实世界中收集交互样本存在高成本以及低效率等问题,因此仿真环境被广泛应用于机器人强化学习训练过程中.通过在虚拟仿真环境中以较低成本获取大量训练样本进行策略训练,并将学习策略迁移至真实环境,能有效缓解真实机器人训练中存在的安全性、可靠性以及实时性等问题.然而,由于仿真环境与真实环境存在差异,仿真环境中训练得到的策略直接迁移到真实机器人往往难以获得理想的性能表现.针对这一问题,虚实迁移强化学习方法被提出用以缩小环境差异,进而实现有效的策略迁移.按照迁移强化学习过程中信息的流动方向和智能化方法作用的不同对象,提出一个虚实迁移强化学习系统的流程框架,并基于此框架将现有相关工作分为3大类:基于真实环境的模型优化方法、基于仿真环境的知识迁移方法、基于虚实环境的策略迭代提升方法,并对每一分类中的代表技术与关联工作进行阐述.最后,讨论虚实迁移强化学习研究领域面临的机遇和挑战.

结合深度强化学习与变形五次多项式的搬运机器人关节轨迹规划

针对在生产节拍固定的情况下搬运机器人各关节的运动轨迹及时间分配问题,构建基于深度强化学习与变形五次多项式相结合的搬运机器人关节轨迹时间分配模型;设计以节拍要求、速度约束和加速度约束为目标的奖励函数,搭建神经网络,利用MATLAB/Simulink软件,得到满足生产节拍和运动学约束的时间序列,并利用单臂四自由度搬运机器人仿真实验,验证所构建模型的可行性和有效性。结果表明:单臂四自由度搬运机器人各关节的运行时间均为5.89 s,其中平移关节1、 3的最大速度分别为2 597.84、 1 697.97 mm/s,最大加速度分别为19 532.11、 31 302.61 mm/s^(2);旋转关节2、 4的速度大小相等且方向相反,最大角速度均为137.53 (°)/s,最大角加速度均为1 180.51 (°)/s^(2),均未超过运动学约束;所构建的模型可以解决在指定生产节拍下搬运机器人关节轨迹时间分配问题,实现搬运机器人搬运过程中各关节的运动均衡,改善搬运机器人运行的稳定性和有效性。

Modeling a Controller for an Articulated Robotic Arm

The precise control upon each degree of freedom of a robotic arm is a great challenge in implementing industrial work. This paper aims to design a novel controller for an automated robotic arm. A discrete Proportional Integral Derivative (PID) control technique is being used to replace the complex electronic circuitry, which would greatly reduce the cost and size of the controller. DC motors will be controlled on the basis of Closed-loop System using an avr (Atmega 16/32) microcontroller. Transfer functions have been derived for mathematical modeling of the system through which the stability of the system can be evaluated prior to fabrication.

双臂移乘护理机器人起抱位置与移乘姿态规划

首先,建立被护理人的4连杆模型,并结合机器人姿态信息建立人机系统力学模型,分析移乘中被护理人的受力(内力、外力);其次,通过问卷调查,确定各内力、外力对人体舒适性影响的权重,建立舒适性评价函数,并运用所建立的舒适性评价函数以优化被护理人移乘舒适性为目的规划起抱位置与姿态。本文进行了接触力和表面肌电(sEMG)测试实验。结果显示:本文方法规划的起抱位置与姿态,能够有效降低被护理人与机器人之间的接触压力,并把移乘中的腰部内力负担减轻44.2%,提高了移乘的舒适性。

基于策略融合及Spiking DRL的移动机器人路径规划方法

深度强化学习(DRL)已被成功应用于移动机器人路径规划中,基于DRL的移动机器人路径规划算法适用于高维环境,是实现移动机器人自主学习的重要方法。而训练DRL模型需要大量的环境交互经验,这意味着更高的计算成本。此外,DRL算法的经验池容量有限,无法确保经验的有效利用。作为类脑计算重要工具之一的脉冲神经网络(Spiking Neural Networks,SNNs)以其独有的生物似真性,能同时融入时空信息,适用于机器人环境感知及控制。结合SNNs、卷积神经网络(CNNs)和策略融合,针对基于DRL的移动机器人路径规划算法进行研究,完成了以下工作:1)提出SCDDPG(SCDDP)算法。该算法利用CNNs对输入状态进行多通道特征提取,利用SNNs对提取的特征进行时空学习。2)在SCDDPG的基础上,提出SC2DDPG(SC2DDPG)算法。SC2DDPG通过设计状态约束策略对机器人运行状态进行约束,避免了不必要的环境探索,提升了SC2DDPG中DRL的收敛速度。3)在SCDDPG的基础上,提出了PFTDDPG(Policy Fusion and Transfer SCDDPG,PFTDDPG)算法。该算法采用分阶控制模式与DRL算法融合,针对环境中的楔形障碍物实施沿墙行走策略,并引入迁移学习对先验知识进行策略迁移。PFTDDPG算法不仅完成了单纯依靠RL不能完成的路径规划任务,还可以得到最优无碰路径。此外PFTDDPG提升了模型的收敛速度和路径规划性能。实验结果证明了所提出的3种路径规划算法的有效性,对比实验结果表明:在SpikeDDPG,SCDDPG,SC2DDPG和PFTDDPG算法中,PFTDDPG算法在路径规划成功率、训练收敛速度、规划路径长度等性能指标上表现最佳。本工作为移动机器人路径规划提出了新思路,丰富了DRL在移动机器人路径规划中的解决方案。

基于传递矩阵法的足式机器人四连杆腿部机构正向与逆向动力学分析

为了保证足式机器人腿部机构的控制准确性与实时性,利用向量代数方法,对足式机器人四连杆腿部机构进行几何运动学分析;根据有限元形函数理论,建立足式机器人四连杆腿部机构典型构件的质量离散方法;在几何运动学分析的基础上,基于力矩平衡原理,分别进行正向与逆向动力学分析;利用线性变换原理并结合传递矩阵法,建立足式机器人四连杆腿部机构正-逆向动力学统一模型,并利用Adams软件建立足式机器人四连杆腿部机构虚拟样机模型,进行正向与逆向动力学仿真实例分析。结果表明,所建立的足式机器人四连杆腿部机构正-逆向动力学统一模型与虚拟样机模型3个油缸力与3个方向足底力的误差分别小于1%与3%,验证了所建立的足式机器人四连杆腿部机构正-逆向动力学统一模型能够精确地求解油缸力与足底力。

基于YOLOv5与迁移学习的目标检测和机械臂抓取位姿估计

针对传统机器学习算法视觉识别准确率低、运行时间缓慢等问题,研究针对家庭场景中机器人做家务的场景,利用RGB图像信息为输入,完成对目标物体的抓取位姿估计。以目标检测模型YOLOv5s为基础,利用其轻便、速度快的优点,结合数据增强以及迁移学习搭建网络架构,搭建家庭场景数据集;将少量训练样本进行数据增强后,利用迁移学习将模型在目标数据集上训练,同时微调参数,将目标物体的定位信息通过坐标变换转换为机械臂的抓取位姿,控制机械臂最终以固定抓取姿态完成抓取任务;最后,通过搭建实验平台,操纵UR5机械臂进行实际抓取实验,验证了算法的有效性。提出的基于目标检测的方法速度快、实时性高、误/漏识别率小于2%,应用在机械臂抓取上可以高效地完成任务。

一种工具坐标系标定与公共点结合的机器人与激光跟踪仪坐标转换方法

机器人标定需要实现测量坐标系与机器人坐标系的配准关联,得到两者之间的转换关系。为克服传统基于轴线矢量坐标系转换方法操作复杂、拟合精度不高等缺点,提出一种工具坐标系标定与公共点转换相结合的解算方法。首先基于距离约束标定出光学靶标球中心相对于末端法兰坐标系的位置参数,而后通过重心化配置降低测量误差对坐标转换的影响,最后基于公共点转换采用三维七参数模型求解坐标转换齐次矩阵。实验结果表明,相比于基于轴线矢量坐标系转换的传统拟合方法,该方法的点位综合MAE减小35.44%,坐标转换精度更高,且操作方法简单,适合工业现场使用。

煤矿辅助运输转载机器人设计研究

为探究煤矿辅助运输工作效率的提升路径,针对部分小型煤矿辅助运输工作的实际需要,首先对煤矿辅助运输转载机器人整体架构进行设计,而后从硬件和软件两方面着手,对机器人的机械结构与运行算法两方面内容作进一步的详细设计,以实现煤矿辅助运输转载机器人的设计目标。

水下机器人磁耦合无线电能传输技术研究进展

水下机器人已成为海底设施巡检和海洋环境调查的关键装备,海底无线充电基站是解决机器人原位电能补给的有效方案。概述磁耦合式水下无线电能传输技术的原理,针对电磁耦合器结构、补偿网络拓扑、涡流损耗分析等主要问题,综述水下无线电能传输技术的研究现状,总结海底无线充电基站的国内外应用进展,并展望水下无线电能传输技术在基础理论和应用方面的发展方向。

新型三维组合式发射线圈的设计与实验

多维无线电力传输是胃肠道胶囊机器人发展的关键。为了解决新型胶囊机器人功能不断增加,而传统三维接收线圈占用内部空间过大的问题,本文提出了一种三维组合式发射线圈,能够通过调制通过各维线圈的电流来产生动态的三维磁场。本文首先介绍了无线供能系统的工作原理,然后对发射系统产生的空间磁场进行了有限元分析。最后利用搭建的实验平台进行实验,验证了仿真结果的准确性并确定了接收线圈感应最大接受电压的姿态。试验结果表明,当发射系统在中心点处产生相等的三维磁场分量时,负载接收能量超过630 mW。此外,发射系统附近边缘区域的位置稳定性超过80%,确保胶囊机器人能够平稳的运行。

煤矿辅助运输转载机器人设计

自动化已经成为当前煤矿行业发展的必然趋势。煤矿辅助运输设备是煤矿生产中不可缺少的设备,对其进行自动化和智能化设计,能够促进生产效率的提高。文章对煤矿辅助运输转载机器人的设计、控制系统的架构进行深入分析,旨在为该类机器人的研发提供相应的理论依据。

胃肠道胶囊机器人无线能量传输系统中发射线圈优化设计

基于无线能量传输的模型与原理,仿真分析了几种不同类型发射线圈的磁场分布。结果表明,线圈磁芯开口大小、磁芯与空气界面的形状、线圈放置的位置都会对发射线圈附近磁场分布产生影响。进而优化出扇环型发射线圈,当线圈中通以频率218 kHz、幅值1.125 A的电流时,可在一定的空间区域形成3.0~4.7 G、比较均匀的磁场,满足胃肠道胶囊机器人的供能需求。相较于已有同用途的发射线圈,优化设计的发射线圈结构简单、整体尺寸显著缩小,同时采用较小的电流就能满足供能需求。研究工作可为优化设计无线能量传输系统中的发射线圈提供新的思路和可行途径。