一种足式移动机器人的混合视觉伺服控制方法

张德伟; 刘海涛; 王仙业; 肖聚亮

doi:10.13433/j.cnki.1003-8728.20200527

一种足式移动机器人的混合视觉伺服控制方法

doi: 10.13433/j.cnki.1003-8728.20200527

天津大学机构理论与装备设计教育部重点实验室，天津　300354

基金项目: 国家自然科学基金项目（51721003，51675369，51775376）与天津市自然科学基金项目（17JCZDJC40100）

详细信息

作者简介:
张德伟（1995−），硕士研究生，研究方向为机器人运动控制，zhangdewei095@tju.edu.cn

通讯作者:
刘海涛，教授，博士生导师，liuht@tju.edu.cn

中图分类号: TP242
计量
- 文章访问数: 193
- HTML全文浏览量: 116
- PDF下载量: 22
- 被引次数: 0
出版历程
- 收稿日期: 2020-12-07
- 网络出版日期: 2023-02-16
- 刊出日期: 2022-12-05

Hybrid Visual Servoing Control of a Legged Mobile Robot

The Ministry of Education Key Laboratory of Mechanism Theory and Equipment Design, Tianjin University, Tianjin 300354, China

摘要

摘要: 针对一种配有单目相机的足式移动机器人，提出一种基于图像单应性的混合视觉伺服方法，利用单应性矩阵中的元素构造状态变量估计估计机器人相对位姿，使机器人在缺乏深度信息的情况下可准确到达目标位姿。相较于轮式移动机器人，在足式机器人移动过程中，足式机构的间歇性运动直接影响机器人视觉反馈过程和伺服控制系统的准确性和稳定性。为解决这一问题，通过分析足式机构运动学并建立足式机器人移动速度与电机转速的映射关系，使控制器可以更准确地调整机器人运动速度。考虑到足式机构运动对视觉反馈环节的影响，提出一种改进型自适应中值滤波算法提高位姿估计精度。伺服环节设计了滑模控制器，并采用李雅普诺夫方法证明了控制系统的稳定性。最后，利用CoppeliaSim软件搭建足式移动机器人虚拟模型，通过仿真验证了所提出控制方案的可行性与有效性。
- 足式移动机器人 /
- 视觉伺服控制 /
- 单应性 /
- 滑模控制
Abstract: This paper investigated a homography-based visual servoing control of a legged mobile robot, which is equipped with a fixed monocular camera. The position of the robot relative to the target object is estimated using state variables constructed withthe elements of a homography matrix. Then, the robot can accuratelyarrive at the desired position without depth information. Compared with a wheeled mobile robot, the intermittent motion of a legged mobile robot directly affects its image processing accuracy and destabilizes the visual servoing control. To address this problem, kinematics of legging mechanisms is analyzed, and the mapping between the velocity of the robot and that of a motor is established to enable the controller to adjust the movement of the legged mobile robot more accurately. To address this problem, kinematics of the legged mechanism is analyzed, and the mapping between velocities of the robot and motor speeds is established to enable the controller to adjust the movement of the legged mobile robot more accurately. Considering the influence of the movement of the legged mechanism on visual feedback, an improved adaptive median filter is proposed to improve the accuracy of the position estimation. Furthermore, a sliding mode controller is designed, and the Lyapunov-based approach is used to analyze the stability of the control system. With the aid of the CoppeliaSim software, themodel of the robot is built to verifythe effectiveness of the proposed method.
- legged mobile robot /
- visual servoing control /
- homography /
- sliding mode control

HTML全文

图 1 足式移动机器人三维模型

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图 2 机器人连体坐标系

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图 3 六杆机构示意图

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图 4 点R_G的运动轨迹

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图 5 点R_A的运动轨迹

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图 6 $ {\dot \varphi} $迭代计算流程

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图 7 坐标系关系

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图 8 改进型自适应中值滤波流程

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图 9 控制系统框图

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图 10 机器人航向角朝向情况

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图 11 四自由度移动平台

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图 12 机架平面运动

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图 13 Δy_r和Δy_l的运动轨迹

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图 14 滤波算法测试结果

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图 15 机器人仿真场景

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图 16 仿真中机器人的移动过程

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图 17 机器人位姿轨迹

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表 1 六杆机构无量纲尺度参数

杆件	符号	长度比
R_AR_B	l_AB	1.00
杆1	l_AE	1.50
杆2	l_BC	4.80
杆3	l_CD	3.00
杆4	l_AD	3.00
杆5	l_EF	6.75
R_CR_F	l_CF	2.50
R_CR_G	l_CG	5.75
R_FR_G	l_FG	7.00

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表 2 机器人尺度参数

l_AB/m	L/m	φ₁/（°）	φ₂/（°）
0.02	0.28	75	255

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表 3 视觉传感器及控制器参数

W	f	$ {\varepsilon _0} $	k₀	k₁	c₁
400	230	0.06	0.12	0.6	0.2

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