具有MY轮的全方位移动机器人运动学研究

根据MY轮的结构特点建立了由MY轮组成的全方位移动机器人的运动学模型.分析了由于轮结构带来的运动学特性.对全方位移动机器人在运动过程中的振动、控制及误差进行了深入研究.提出了通过优化接触距离及MY轮转速来减小机器人运动误差的控制方法.为获得优化结构,比较了三轮结构和四轮结构的运动学特性.同时应用正弦控制规律来合理控制MY轮的转动,改善了机器人的运动稳定性.仿真结果充分证明了分析的正确性.     

可跳跃式两轮机器人的设计与动力学分析

为提高跳跃机器人运动的灵活性和实用性,通过将跳跃运动与轮式运动相结合,设计了一种新型的可跳跃式两轮机器人.跳跃运动由三杆弹簧跳跃机构实现,在大大减小机构尺寸的同时提高了能量利用率.详细介绍了机器人各机构的组成及工作原理,在此基础上,对机器人跳跃过程进行了动力学建模,分析了影响机器人跳跃能力的因素.为验证机械设计的有效性,利用ADAMS进行了机器人轮式移动与跳跃越障过程的仿真.搭建机器人控制系统并制作可跳跃式两轮机器人原理样机,最终跳跃实验结果证明了机器人设计的合理性以及理论分析的正确性.该跳跃机器人的能量利用效率接近70%,跳跃高度超过自身尺寸.     

全方位移动装配机器人运动学分析

针对空间狭小拥挤、地面不平的特殊装配环境,设计了一种5自由度全方位移动装配机器人.该机器人主要由基于4组并联布置的MY(mutual Yo Yo)轮的全方位移动平台和具有2自由度的并联举升机构组成.首先,针对该机器人的全方位运动和并联举升机构的2自由度结构特点,建立了机器人的整体运动学模型,并基于该模型对机器人进行了圆形曲线轨迹仿真.然后,设计双曲线滤波PD(proportional derivative)控制器对机器人的轨迹进行跟踪并分析其轨迹跟踪误差.该控制器能控制平均误差在5 mm左右,且误差随跟踪时间减小而减小.最后,通过实验结果验证了该运动学模型和仿真结果的正确性,且该控制器能迅速并精确地实现其轨迹跟踪,从而进一步验证了该全方位移动装配机器人的优越性.     

轮腿式微型机器人系统研究

轮腿复合式机器人是在轮式机器人的基础上,通过优化轮子设计以达到快速灵活运动的一种新型的地面移动系统。该机器人主体由机架、两条主轴、齿轮减速机构、轮腿复合机构组成,由单电机驱动,控制系统相对简单。该机器人相比于普通轮式机器人具有较强的越障能力,且结构精简、体积小、重量轻。采用ADAMS对该机器人进行了运动学和动力学仿真,详细探讨了其越障能力、安装相位、轮腿结构、步态等关键问题,为其物理样机的设计、优化和控制提供了理论依据。     

全方位越障移动机构研究

针对清洗壁面作业对机器人提出的特殊要求,研制了可越障轮式全方位移动机构—— -车轮组机构,该机构保证机器人在姿态保持不变的前提下,沿壁面任意方向直线移动、或 在原地旋转任意角度,同时能跨越存在于机器人运行路径中的障碍．该机构不需要传感装置 来检测障碍,不需要复杂的辅助机构来实现平面上运动和越障运动之间的转换．     

两栖机器人轮桨腿驱动机构多目标优化设计

提出了一种既能够在陆地上爬行,又能够在一定深度的水下浮游和在海底爬行的新概念轮桨腿一体化两栖机器人;多运动模式和复合移动机构是该机器人的突出特点．分析了轮桨腿复合式驱动机构的运动机理,并采用多目标优化设计理论和算法,对驱动机构的爬行性能和浮游特性进行了综合优化,得到了两栖机器人驱动机构的结构优化参数．虚拟样机的仿真结果证明了该轮桨腿一体化两栖机器人驱动机构的综合运动性能良好,对非结构环境具有一定的适应能力．     

自动泊车轨迹生成方法的研究

轮式移动机器人是机器人学的重要分支,广泛地应用于消防,军事等领域.轮式移动机器人属于非完整约束系统,也是典型的强非线性系统,一般的控制理论很难能够适用.根据重复变换法对轮式移动机器人自动泊车轨迹的生成作了尝试,通过移动机器人的两驱动轮的9种可能的微小移动组合,利用顺运动学计算出与其对应机器人的位置和姿态,选取最优解,实现了机器人在障碍及非障碍环境下的自动泊车,对移动机器人优化路径,提高姿态性能,通过仿真证明了算法的可行性,生成的泊车轨迹同人操纵下泊车的轨迹非常相似.     

一种两轮轮式机器人点镇定智能控制实现

针对实际RoboCup机器人,分析了采用双闭环轮速跟随电机执行系统的两轮轮式移动机器人的数学模型,考虑了实际电机系统必然存在的速度饱和、加速度饱和限制对点镇定控制的影响,基于动觉图式的仿人智能控制理论,提出了一种两轮轮式机器人点镇定的分段比例智能控制器,利用遗传算法整定了控制器的参数.比较了比例控制器,比例余弦控制器和提出的智能控制器的仿真控制效果,并在实际RoboCup机器人上有效实现了提出的控制器.仿真和实际系统实验都证明了该控制器的有效性.     

具有拨土功能的轮腿一体化机器人结构设计

针对矿井灾难环境特点,采用三维建模软件设计了一种轮腿一体化机器人.该机器人采用轮腿一体式结构,具备了腿式机器人和轮式机器人的运动优点.分析了在不同环境下机器人采用的行进方式(即机器人步态),增强了机器人的环境适应能力,并且设计了基于多传感器信息的运动控制系统.该系统能够完成灾难矿井下的环境探测、信息获取以及机器人步态控制等功能,为矿难救援工作提供了重要的信息.     

轮足复合移动机器人运动规划发展现状及关键技术分析

地面移动机器人已经在资源勘探和灾难救援等多领域得到广泛应用,轮足复合机器人能够结合轮式运动速度快、平稳性高和足式运动的高越障性能等多方面优势,在理论创新和工程技术方面均有重要的研究价值.对近年来国内外轮足复合机器人的机械结构进行分析和比较,将轮足机构复合方式分为4类进行列举和总结.针对多模态运动的优势展开分析,列举轮足复合机器人主要采用的运动建模、规划和控制策略,不仅涉及单独的足式运动和轮式运动,同时涉及足端越障、变构型避障、轨迹规划的轮足复合运动.最后对运动规划关键技术进行总结和展望,指出轮足复合移动机器人后续的发展方向、研究思路和所面临的挑战.     

Kinematic modeling of wheeled mobile robots

We formulate the kinematic equations of motion of wheeled mobile robots incorporating conventional, omnidirectional, and ball wheels.¹ We extend the kinematic modeling of stationary manipulators to accommodate such special characteristics of wheeled mobile robots as multiple closed-link chains, higher-pair contact points between a wheel and a surface, and unactuated and unsensed wheel degrees of freedom. We apply the Sheth-Uicker convention to assign coordinate axes and develop a matrix coordinate transformation algebra to derive the equations of motion. We introduce a wheel Jacobian matrix to relate the motions of each wheel to the motions of the robot. We then combine the individual wheel equations to obtain the composite robot equation of motion. We interpret the properties of the composite robot equation to characterize the mobility of a wheeled mobile robot according to a mobility characterization tree. Similarly, we apply actuation and sensing characterization trees to delineate the robot motions producible by the wheel actuators and discernible by the wheel sensors, respectively. We calculate the sensed forward and actuated inverse solutions and interpret the physical conditions which guarantee their existence. To illustrate the development, we formulate and interpret the kinematic equations of motion of Uranus, a wheeled mobile robot being constructed in the CMU Mobile Robot Laboratory.     

Trajectory generation and control for four wheeled omnidirectional vehicles

This paper describes an algorithm to calculate near-optimal minimum time trajectories for four wheeled omnidirectional vehicles, which can be used as part of a high-level path planner. The algorithm is based on a relaxed optimal control problem. It takes limited friction and vehicle dynamics into account, as encountered in high-performance omnidirectional vehicles. The low computational complexity makes the application in real-time feasible. An implementation of the algorithm on a real vehicle is presented and discussed.     

Design and Optimization of an Omnidirectional Permanent-Magnetic Wheeled Wall-Climbing Microrobot with MEMS-Based Electromagnetic Micromotors

The paper presents a compact omnidirectional permanent-magnetic wheeled wall-climbing microrobot. A millimeter-sized axial flux electromagnetic micromotor based on MEMS technology has been specially fabricated for the microrobot and its size is 6.8 mm × 7.8 mm × 3.9 mm. A novel permanent-magnetic wheel is designed, which is directly integrated with the stators and rotor of the electromagnetic micromotor. The omnidirectional wall-climbing mechanism is realized by a set of steering gears and three standard permanent-magnetic wheels. By static and dynamic force analysis of the microrobot, the required magnetic force and the required torques for its translational and steering movements are derived. To reduce the unnecessary torque consumption of the microrobot, its structural parameters are optimized in combination with its design constraints by ANSOFT and Pro/Engineer simulation. A prototype of the proposed microrobot with the maximum designed load capacity of 3 g is developed, whose size is 26 mm in diameter and 16.4 mm in height. Experimental and simulation results demonstrate the feasibility of these concepts.     

一种小型轮式平台的设计与运动仿真

针对传统轮式车辆转向半径大,转向阻力大的问题,提出一种新型的轮式车辆平台方案。该平台的运动机构由定轴转动的前轮和万向轮后轮组成,主动轮是由轮毂电机独立驱动的前轮,后轮为从动轮;平台采用电驱动,包含电源系统,控制系统,车体等几大部分,相比于传统的车辆,该平台引进了万向轮,大大加强了平台的灵活性,转向更加方便;通过在Solid Works中建立模型,然后在RecurDyn中进行仿真,设置不同的实验条件,根据实验结果可以得到:当后轮为万向轮时,平台相对于后轮固定具有较好的转弯能力,横摆角速度减小,平台转弯更加平稳;同时,平台具有一定的越障能力,可以在一定的复杂地形上完成运动,能够跨越一定尺寸的壕沟。这一结果可以为科学研究和实际应用提供理论依据。     

在球面运行的万向轮式移动机器人运动学模型的建立

爬壁机器人技术的不断发展,使研制可以吸附在大 型球面工作的轮式移动机器人成为可能．本文采用坐标变换方法,针对工作在球面的万向轮 式移动机器人建立运动学模型．其建模方法对于其它类型的在球面工作的轮式移动机器人也 同样适用．     

轮式移动机器人在圆形管道中的运动学建模与分析

为解决圆形管道中轮式移动机器人的运动控制问题,分析了轮式移动机器人在圆形管道中的运动学特性．借助接触点的切平面,单个轮子在平面上的位置和运动描述方法被应用在圆管的柱面上．推导了单个轮子在柱面上纯滚动时轮心的轨迹和速度．运用刚体运动瞬时螺旋理论,对由两个固定轮和一个舵轮组成的(1,1)型三轮机器人在圆形管道中的运动进行了建模分析,并对此运动学模型进行了仿真．     

The kinematics for redundantly actuated omnidirectional mobile robots

Omnidirectional mobile robots have been popularly employed in several application areas. However, the kinematics and singularity analysis for these systems have not been clearly identified, especially for the redundantly actuated case, which is common in current omnidirectional mobile robots. In light of this fact, this article introduces two different kinematic approaches for a typical omnidirectional mobile robot having three caster wheels, and examines singularity configurations of such systems. Then, a singularity‐free load‐distribution scheme for a redundantly actuated three‐wheeled omnidirectional mobile robot is proposed. Through simulation, several advantages of the redundantly actuated mobile robot (singularity avoidance, input‐load saving, and exploiting several subtasks) are presented. © 2002 Wiley Periodicals, Inc.     

基于关联规则挖掘的全向轮移动机器人目标跟踪控制系统设计

为使全向轮机器人在移动过程中所捕获到的目标对象能够完全符合理想目标设定条件,准确追踪目标节点的运动行为,设计基于关联规则挖掘的全向轮移动机器人目标跟踪控制系统。根据CAN主控框架的部署形式,按需连接核心管控电路与I/O跟踪模块,分别以转向控制器、速度控制器为例,完善全向轮控制结构的物理作用能力,实现机器人目标跟踪控制系统的应用结构部件设计。在此基础上,定义频繁项集合,按照具体的关联规则特征描述结果,确定挖掘程序指令的执行能力,得到准确的关联离散度指标计算结果,实现控制系统的关联规则挖掘,再联合相关硬件设备结构,完成基于关联规则挖掘的全向轮移动机器人目标跟踪控制系统设计。分析对比实验结果可知,随着关联规则挖掘控制系统的应用,全向轮机器人在移动过程中所捕获到的目标对象能够将理想目标完全包含在内,可以辅助全向轮移动机器人更加准确地追踪目标节点的运动行为,符合实际应用需求。     

Kinematic analysis and simulation of active-caster robotic drive with ball transmission (ACROBAT-S)

In this study, a new type of active-caster with a single ball transmission (ACROBAT-S) was proposed. The proposed ball transmission involved a novel mechanism that realized to control the active-caster for propelling robotic platforms. The combined power from two motors rotated a single ball in two dimensions. Additionally, the combined power was simultaneously decomposed to the wheel shaft and steering shaft of an active-caster in an appropriate ratio. The transmission design enabled an omnidirectional robot with three active-casters to control its 3D motion by three motors with no redundancy. The new concept of ACROBAT-S offers several advantages as compared to the previous ACROBAT design as the number of balls was reduced from two to one, and therefore the number of friction drives between a ball and rollers or a ball and another ball was also reduced from five to three. These features could contribute to simplifying the mechanism design and to reduce transmission slippages and energy losses. The design concept was verified by deriving and analyzing the kinematics of a single ball transmission mechanism and a three-wheeled omnidirectional mobile robot. Furthermore, the motions of ACROBAT-S and that of an omnidirectional robot were verified using computer simulations. The results confirmed that the proposed single ball transmission could be applied to an omnidirectional wheel mechanism to realize non-redundant omnidirectional motions.     

Analysis and Control for an Omnidirectional Mobile Manipulator

This paper describes analysis and control for a holonomic omnidirectional mobile manipulator, in which the holonomic omnidirectional platform consists of three lateral orthogonal wheel assemblies and a mounted manipulator with three rotational joints is located at the center of gravity of the platform. We first introduce the kinematic model for the mobile manipulator and derive the dynamical model by using the Newton–Euler method, where a model which simultaneously takes account of features of both the manipulator and the mobile parts is given to analyze the effect of the movement of mounted manipulator on the platform. Then, the computed torque control and the resolved acceleration control methods are used to show that the holonomic omnidirectional mobile manipulator can be controlled so as to retain any end-effector position and orientation, irrespective of the direction of external applied force. The validity of the model and the effectiveness of the present mobile manipulator are proved by using several numerical simulations and 3D animations.