连续型同心管机器人正运动学快速求解方法

针对可在受限环境中灵活运动的连续型同心管机器人传统正运动学方法计算时间较长,不利于机器人实时运行的问题,本文提出了基于机器人几何学的同心管机器人正运动学快速求解方法,能够在精度损失有限的情况下,提高正运动学模型的计算效率.先根据Cosserat杆模型对同心管机器人进行建模,再利用李代数理论建立了机器人空间位置和曲率的关系式,并结合提出的正运动学方法,对机器人进行了基于逆运动学的开环控制实验.最后通过3管机器人的仿真和实物实验验证了本文所提方法的快速性和有效性.     

医用机器人运动学参数最优化设计

提出了一种实用的医用机器人运动学参数误差的优化补偿方法．采用D-H方法建立起机器人连杆坐标系．在运动学分析和模型变换的基础上，运用数值优化技术建立了机器人运动学参数的误差方程，实现了运动学参数的优化设计，有效提高了机器人的重复定位精度．以仿真和实验验证的方式对优化结果进行了分析．     

五轮铰接式月球机器人的运动学建模

本文为在有壕沟、台阶和斜坡的复杂三维地形上行驶的轮式移动机器人提出了一种新 的运动学建模方法：切平面拼接法．该方法的主要思想是用机器人在不同时刻不同斜面上的 运动学模型组成机器人在崎岖不平地面上行驶的复合运动学模型．该建模方法简单,建模的 精确性可以控制．作者用该方法建立了五轮铰接式月球机器人（FWALR）在崎岖不平地面上 行驶的正向和逆向运动学模型,为FWALR机器人在复杂三维地形上的运动控制奠定了基础．     

UPE: Utah prototyping environment for robot manipulators

Developing an environment that enables optimal and flexible design of robot manipulators using reconfigurable links, joints, actuators, and sensors is an essential step for efficient robot design and prototyping. Such an environment should have the right mix of software and hardware components for designing the physical parts and the controllers, and for the algorithmic control of the robot modules (kinematics, inverse kinematics, dynamics, trajectory planning, analog control and digital computer control). Specifying object-based communications and catalog mechanisms between the software modules, controllers, physical parts, CAD designs, and actuator and sensor components is a necessary step in the prototyping activities.In this paper, we propose a flexible prototyping environment for robot manipulators with the required subsystems and interfaces between the different components of this environment. This environment provides a close tie between the design parameters of the robot manipulator by the different subsystems involved in the design process. The design and implementation of this environment along with the implementation of some of the subsystems are presented, and some examples that demonstrate the functionality of the environment are discussed. This work was supported in part by DARPA grant N00014-91-J-4123, NSF grant CDA 9024721, and a University of Utah Research Committee grant. All opinions, findings, conclusions or recommendations expressed in this document are those of the author and do not necessarily reflect the views of the sponsoring agencies.     

仿人机器人轻型高刚性手臂设计及运动学分析

重点研究了7自由度轻型高刚性作业型仿人机器人手臂的机构设计和运动学分析方法.首先使用动力学仿真、有限元分析与实验测试相结合的方法,设计了仿人机器人手臂,该机械臂结构紧凑、质量轻、刚度高.同时,提出结合查询数据库和逆运动学计算去模仿人类手臂姿态,从而获得逆运动学最优解的方法.该方法不仅解决了冗余自由度带来的逆运动学多解问...     

Forward and inverse kinematics of a 5-DOF hybrid robot for composite material machining

Hybrid robots consist of both serial and parallel mechanisms, which have advantages in stiffness and workspace compared with serial/parallel robots when machining composite material. However, the forward and inverse kinematics of hybrid robots generally do not have analytic solutions. This paper deals with the analytic forward and inverse kinematics solutions of a 5-degree-of-freedom (DOF) hybrid robot which consists with a 3-DOF 2UPU/SP parallel mechanism (PM) and a 2-DOF rotating head. In the forward kinematic problem, a method is proposed to transfer the high order kinematic equation to a 4th-order polynomial based on the Sylvester's dialytic elimination, and the analytic solutions can be further obtained by Ferrari's method. In the inverse problem, the redundant Euler angles expressed by four rotations are firstly proposed for decoupling different motions, then, the closed-form solution of inverse kinematics can be found. Finally, a simulation trajectory is given, and the result shows that the accuracy of the solutions’ calculation reaches femtometer grade and the efficiency reaches microsecond grade; furthermore, an experiment is performed on the prototype to validate the effectiveness of the proposed forward and inverse kinematics.     

基于遗传算法的机器人运动学逆解

在分析以往逆解方法的基础上，提出了用遗传算法求解机器人运动学逆解的方法，给出了用于优化求解的适合度函数，并提出用二次编码法提高解的精度．计算机模拟证明：该方法能快速收敛于全局最优解，能给出机器人的可能解，并能计算冗余度机器人的逆解．     

Error-back-propagation solution to the inverse kinematic problem of redundant manipulators

In this paper, the inverse kinematics problem of the generalized n-degrees-of-freedom robot is solved using the error-back-propagation algorithm. The efficiency of the proposed solution has been mewed for redundant manipulators using 5000 randomly chosen Cartesian coordinates within the robot's workspace. Comparison with two other methods, the well-known pseudoinverse method and a technique based on genetic algorithms, shows that the accuracy of the present method is substantially better.     

Wheeled mobile robot navigation using proportional navigation

We present a method for wheeled mobile robot navigation based on the proportional navigation law. This method integrates the robot's kinematics equations and geometric rules. According to the control strategy, the robot's angular velocity is proportional to the rate of turn of the angle of the line of sight that joins the robot and the goal. We derive a relative kinematics system which models the navigation problem of the robot in polar coordinates. The kinematics model captures the robot path as a function of the control law parameters. It turns out that different paths are obtained for different control parameters. Since the control parameters are real, the number of possible paths is infinite. Results concerning the navigation using our control law are rigorously proven. An extensive simulation confirms our theoretical results.     

仿尺蠖多模式爬壁机器人设计与控制方法研究

对于高层建筑清洁、大型化工罐体焊接与检测以及管道、隧道等狭小空间的安全巡查,传统方式为人工操作,存在安全隐患及效率低下等缺点,针对这些问题,提出了一种爬壁机器人设计方案。通过研究自然界尺蠖类生物的壁面攀爬机理,结合仿生技术,利用真空吸附和爪刺抓附两种附着技术,研发了一种仿尺蠖多模式爬壁机器人。首先在静态条件下,采用D-H参数法建立了机器人运动学数学模型,求解了机器人运动学的正、逆解,然后进行了基于极坐标理论的机器人控制方法研究,分析了了步态控制策略,并基于嵌入式控制器搭建了实际样机的控制系统,进行了功能性测试,验证了爬壁机器人的运动学模型的正确性和步态控制方法的平稳性,为双足类仿生机器人进一步研究提供了参考。     

Adaptive task-space regulation of rigid-link flexible-joint robots with uncertain kinematics

In this paper, an adaptive control scheme is proposed for the regulation problem of rigid-link flexible-joint (RLFJ) robots with uncertain kinematics. Existing research works in literature on RLFJ robot control assume exact knowledge of the kinematics of robot, and no result that can deal with kinematics uncertainty in RLFJ robot has been proposed so far. This paper presents the first study addressing this problem. The adaptive control scheme proposed can deal with the kinematics uncertainty and uncertainties in both link and actuator dynamics of the RLFJ robot system. A nonlinear observer is designed to avoid the use of acceleration due to the fourth-order overall dynamics. Asymptotic stability of the closed-loop system is shown and sufficient conditions are presented to guarantee the stability. Simulation results are provided to illustrate the effectiveness of the proposed control method.     

A global approach for the optimal path generation of redundant robot manipulators

In this article the optimal path generation of redundant robot manipulators is considered as an optimization problem, with given kinematics and subject to the robot requirements and a singularities avoidance constraint. This problem is formulated as a constrained continuous optimal control problem, which allows to consider joints and velocities constraints and/or manipulator dynamics. This approach is exemplified for a planar redundant manipulator and the resultant state constrained problem is solved by an efficient iterative numerical technique.     

A Heuristic Approach to the Inverse Differential Kinematics Problem

Inversion of the kinematics of manipulators is one of the central problems in the field of robot arm control. The iterative use of inverse differential kinematics is a popular method of solving this task. Normally the solution of the problem requires a complex mathematical apparatus. It involves methods for solving equation systems as well as algorithms for optimization. In this paper we introduce a naïve heuristic method which works without the need for complex mathematical algorithms. This method forms a simple basis for the more sophisticated control procedures of our robot manipulator (JANUS).     

Neural networks and the inverse kinematics problem

Inverse kinematics is a fundamental problem in robotics. Past solutions for this problem have been realized through the use of various algebraic or algorithmic procedures. In this paper the use of feedforward neural networks to solve the inverse kinematics problem is examined for three different cases. A closed kinematic linkage is used for mapping input joint angles to output joint angles. A three-degree-of-freedom manipulator in 3D space is used to test mappings from both cartesian and spherical coordinates to manipulator joint coordinates. A majority of the results have average errors which fall below 1% of the robot workspace. The accuracy indicates that neural networks are an alternate method for performing the inverse kinematics estimation, thus introducing the fault-tolerant and high-speed advantages of neural networks to the inverse kinematics problem.This paper also shows the use of a new technique which reduces neural network mapping errors with the use of error compensation networks. The results of the work are put in perspective with a survey of current applications of neural networks in robotics.     

并联3-URS踝关节康复机器人的机构与运动学研究

为了帮助患者进行踝关节康复训练,减轻治疗师工作强度,在分类分析现有的各类型踝关节康复机器人的基础上,设计了一种六自由度并联3-URS踝关节康复机器人。从人体生理结构及康复训练需求出发,设计、优化了康复机器人结构,加工制造了实物样机模型;采用闭环矢量的方法建立了并联机器人运动学模型,结合Rosenbrock-Banana优化函数,将正逆运动学数值求解问题转换为优化问题。以背屈训练轨迹作为数值算例,求解精度可达10-10~10-7mm;结合虚拟样机技术,验证了该并联机器人运动学优化求解方法的可靠性,适用于3-URS并联踝关节康复机器人。     

A New Geometric Subproblem to Extend Solvability of Inverse Kinematics Based on Screw Theory for 6R Robot Manipulators

Geometric inverse kinematics procedures that divide the whole problem into several subproblems with known solutions, and make use of screw motion operators have been developed in the past for 6R robot manipulators. These geometric procedures are widely used because the solutions of the subproblems are geometrically meaningful and numerically stable. Nonetheless, the existing subproblems limit the types of 6R robot structural configurations for which the inverse kinematics can be solved. This work presents the solution of a novel geometric subproblem that solves the joint angles of a general anthropomorphic arm. Using this new subproblem, an inverse kinematics procedure is derived which is applicable to a wider range of 6R robot manipulators. The inverse kinematics of a closed curve were carried out, in both simulations and experiments, to validate computational cost and realizability of the proposed approach. Multiple 6R robot manipulators with different structural configurations were used to validate the generality of the method. The results are compared with those of other methods in the screw theory framework. The obtained results show that our approach is the most general and the most efficient.

     

Design and motion planning of an autonomous climbing robot with claws

This paper presents the design of a novel robot capable of climbing on vertical and rough surfaces, such as stucco walls. Termed CLIBO (claw inspired robot), the robot can remain in position for a long period of time. Such a capability offers important civilian and military advantages such as surveillance, observation, search and rescue and even for entertainment and games. The robot’s kinematics and motion, is a combination between mimicking a technique commonly used in rock climbing using four limbs to climb and a method used by cats to climb on trees with their claws. It uses four legs, each with four-degrees-of-freedom (4-DOF) and specially designed claws attached to each leg that enable it to maneuver itself up the wall and to move in any direction. At the tip of each leg is a gripping device made of 12 fishing hooks and aligned in such a way that each hook can move independently on the wall’s surface. This design has the advantage of not requiring a tail-like structure that would press against the surface to balance its weight. A locomotion algorithm was developed to provide the robot with an autonomous capability for climbing along the pre-designed route. The algorithm takes into account the kinematics of the robot and the contact forces applied on the foot pads. In addition, the design provides the robot with the ability to review its gripping strength in order to achieve and maintain a high degree of reliability in its attachment to the wall. An experimental robot was built to validate the model and its motion algorithm. Experiments demonstrate the high reliability of the special gripping device and the efficiency of the motion planning algorithm.     

Conceptual design and analysis of the 2T1R mechanism for a cooking robot

This paper deals with the design and analysis of a two-translation and one-rotation (2T1R) mechanism for a novel cooking robot. Firstly the motions involved in stir-fry, the most representative operation in the cooking processes used in Chinese cuisine, are analyzed in details. Then the featured motions are decomposed into four main movements that are used as a design base for a wok motion mechanism. Several three-degrees-of-freedom (DOF) parallel manipulators are considered. From these, a 2T1R mechanism is selected as an ideal candidate. A 4-DOF (2T1R+1T) cooking robot is constructed by combining the 2T1R parallel manipulator with a 1-DOF linear feed mechanism. It is shown that the combined 4-DOF robot can perform the required cooking operations, particularly the stir-fry. The analysis conducted on the proposed 2T1R parallel manipulator includes inverse kinematics, forward kinematics, the velocity analysis, the constant orientation workspace, and the total orientation workspace. A prototype of the cooking robot is developed. The experiments verify that the proposed cooking robot is suitable for performing the required operations.     

机器人灵活工作空间的边界分析

机器人灵活工作空间的分析是机器人运动学至今没有解决的一个问题.由于机器人在灵活工作空间中工作不会受到本身机构对它的限制.所以,机器人灵活工作空间的大小对于提高机器人的操作性能就显得格外重要.本文旨在解决机器人灵活工作空间边界的计算问题.首先.它分析了灵活工作空间边界的性质;其次,用一种新的方法——网络跟踪法确定了灵活工作空间在横截面内的边界;最后.提出了灵活工作空间端边界的求解方法.     

钢丝绳传动机器人运动学的支路分析方法

通过研究分析一类[N+1]条钢丝绳驱动[N]个自由度机器人的运动学,其运动学可通过推导移去钢丝绳后开环链机器人关节空间与笛卡尔空间之间的运动学关系和关节空间与驱动空间之间的运动学关系来完成。在基本回路、共轴条件和传动线运动学分析的基础上,提出了用支路矩阵和等效半径矩阵描述钢丝绳传动机器人运动学的支路分析方法。根据钢丝绳传动原理,通过观察法可直接列写支路矩阵和驱动空间等效半径矩阵,从而得到了驱动空间与关节空间之间的运动学映射关系,解耦了由于钢丝绳传动导致机器人关节间的运动耦合。结合传统机器人运动学,实现了驱动空间、关节空间和笛卡尔空间完整运动学映射关系,加快和简化了钢丝绳传动机器人运动学建模和分析过程。以Stanford/JPL手指为例进行了运动学分析和仿真,验证了用支路矩阵和等效半径矩阵描述钢丝绳传动机器人运动学支路分析方法的正确性,为钢丝绳传动机构的设计、运动学分析与控制奠定了基础。