采用单节变形履带机构的越障轮椅机器人机理研究
文献类型：学位论文
| 作者 | 于苏洋 |
| 学位类别 | 博士 |
| 答辩日期 | 2013-11-20 |
| 授予单位 | 中国科学院沈阳自动化研究所 |
| 导师 | 王志东 |
| 关键词 | 轮椅机器人 单节变形履带机构 驱动力矩 倾翻与滑移稳定性 履带张紧力 自主爬越楼梯 |
| 其他题名 | Research on the Wheelchair Robot Equipped with a Variable Geometry Single Tracked Mechanism (VGSTM) |
| 学位专业 | 模式识别与智能系统 |
| 中文摘要 | 本文的研究内容主要围绕国家自然科学基金项目“越障轮椅机器人的机构、动力学及稳定性研究”展开。该项目提出一种采用单节变形履带机构的新型越障轮椅机器人的机构方案。该机器人能够通过前、后摆臂主动控制履带的形状与张紧力，使履带能够主动产生与障碍物相适应的变形，从而进一步提高了传统轮椅及现有越障轮椅机器人的越障能力。针对这种新型越障轮椅机器人，本文选取爬越楼梯这种典型越障运动，进行了相关的机理(即为实现特定功能，系统内各要素的运行规则与原理)研究，并且研究内容可概括为机器人的“机构方案实现”、“运动性能实现”以及“自主性能实现”三个部分。(1)“机构方案实现”要在所提出的轮椅机器人机构方案的基础上，通过理论分析指导机器人的后续设计，并初步验证机构方案的合理性，最终制作出机器人的样机。为了指导机器人的后续设计，本文针对爬越楼梯过程，利用转化为等效串联机器人的方法建立了机器人的几何模型，利用Lagrange方法建立了机器人的动力学模型。在此基础上，针对履带与楼梯间作用力在机器人处于过约束状态时不能全部独立求解的情况，提出了一种机器人主动构件驱动力矩的优化求解方法。通过仿真得到了机器人爬越楼梯过程中各主动构件关节变量与驱动力矩的变化情况，为指导机器人的后续设计工作提供了理论基础。为了验证机器人机构方案的合理性，本文选取倾翻稳定性这一指标，利用Force-Angle方法推导出机器人爬越楼梯过程的倾翻稳定角，并且在推导过程中，通过建立仿人机器人模型实现了对乘坐者姿态与动作的描述。通过仿真得到了在机器人不同运动状态以及乘坐者不同姿态与动作的影响下，机器人爬越楼梯过程中倾翻稳定角的变化情况，从倾翻稳定性的角度验证了机器人机构方案的合理性。在理论分析的指导下，机器人的样机得以制作完成。进而本文利用样机进行了手动控制模式下的爬越楼梯实验，验证了机器人的基本越障能力。(2)“运动性能实现”要在“机构方案实现”的基础上，通过理论分析为机器人在稳定性和履带张紧力这两方面以理想的运动状态完成爬越楼梯运动提供基础。在稳定性方面，本文通过对过约束状态下机器人履带与楼梯间作用力的近似求解，以及履带与楼梯间的滑移分析，建立了一种能够同时评判倾翻与滑移情况的稳定性评判准则。通过仿真得到了机器人爬越楼梯过程中履带与楼梯间作用力的变化情况，验证了机器人不会发生倾翻与滑移稳失稳，以及履带与楼梯间作用力近似求解方法的有效性。同时，所建立的稳定性准则为机器人以理想的稳定性状态完成爬越楼梯运动提供了基础。在履带张紧力方面，本文针对机器人爬越楼梯过程的不同运动状态，分别建立了机器人整体及主要构件的静力学模型，得到了机器人所受到的楼梯作用力、履带张紧力以及主动构件驱动力之间的约束关系。在此基础上，根据履带张紧力对机器人运动性能的影响建立了履带张紧力优化模型。通过仿真得到了机器人爬越楼梯过程最优被控履带张紧力值的变化情况，为机器人以理想的履带张紧力状态完成爬越楼梯运动提供了基础。(3)“自主性能实现”要在“机构方案实现”与“运动性能实现”的基础上，通过有效的方法使机器人具备考虑乘坐者影响的自主爬越楼梯能力。为了使机器人能够自主爬越楼梯，本文首先根据各主动构件的功能将机器人的自主控制划分为驱动轮与后摆臂控制，以及前摆臂控制两部分。之后，针对驱动轮与后摆臂，建立了一种能够根据机器人所处位置进行运动与变形决策，以及倾翻与滑移稳定性评判的控制策略；针对前摆臂，建立了一种基于力位切换思想，能够根据机器人几何模型与履带张紧力优化结果控制履带张紧程度的控制策略。为了在控制策略中考虑乘坐者的影响，本文建立了一种通过搭建压力传感系统检测乘坐者对座椅压力中心的方法。进而，通过给定压力中心与乘坐者典型姿态的对应关系实现了对乘坐者典型姿态的辨识，并以此完善了机器人的自主爬越楼梯控制策略。 |
| 索取号 | TP242/Y74/2013 |
| 英文摘要 | The research in this dissertation is based on a project supported by National Natural Science Foundation of China. In the project, the mechanism scheme of a new-style wheelchair robot equipped with a variable geometry single tracked mechanism (VGSTM) is proposed. The robot can actively control the robot shape and track tension by the two pairs of flippers to make the robot shape adapt for the obstacle, so the obstacle clearing ability of traditional wheelchairs and existing wheelchair robots is improved. With the aim of stair-climbing, which is the most important obstacle clearing performance of the wheelchair robot, the objectives that the research in this dissertation needs to realize can be divided into three steps as the realizations of the mechanism scheme, the motion state, and the automatical movement.(1) In the realization of the mechanism scheme, some theoretical analysis needs to be performed to guide the design work of the robot and verify the rationality of the mechanism scheme, and then the prototype of the root can to be built.In order to guide the design work of the robot based on the mechanism scheme, in this paper a geometric model of the robot is established by transforming the robot to an equivalent serial manipulator, and a dynamic model is also established with Lagrange method. Based on the models, for dealing with the situation that the forces between the track and stairs can not be solved out accurately when the robot is over-constrained, an optimal solution method of the driving moments is proposed. Then from simulations, the variations of the joint variables and driving moments of the driving components during stair-climbing are obtained, and the simulation result gives important guidance to the design work of the robot.In order to verify the rationality of the mechanism scheme, in this paper the tip-over stability is selected as the analysis objective, and the stability angle of the robot during stair-climbing is obtained with Force-Angle method. In this process, a humanoid robot is established to describe the attitude and action of the passenger. Then from simulations, the variation of the stability angle during stair-climbing under the influence of the motion states of the robot and the passenger's attitude and action are obtained, and the simulation result indicates that the tip-over instability will not happen for the proposed mechanism scheme of the robot.With the guidance of the theoretical analysis, the prototype of the robot is built, and the experiment of stair-climbing in manual control mode is performed. The experiment result verifies the basic ability of obstacle clearing of the robot.(2) In the realization of the motion state, some theoretical analysis needs to be performed to provide foundations for the wheelchair robot to climb stairs with a good state of stability and track tension.In the aspect of stability, in this paper first the approximate solution of the forces between the track and stairs for the situation that the robot is over-constrained is realized, and the slippage between the track and stairs is analyzed systematically. Based on the above work, a new stability criterion that can consider both the tip-over and slippage situations is established. Then from simulations, the variations of the forces between the track and stairs during stair-climbing are obtained, and the simulation result indicates that the tip-over and slippage instability will not happen, and the proposed approximate solution method of the forces between the track and stairs is rational. Meanwhile, the new stability criterion provides a foundation for the robot to climb stairs with a good state of stability.In the aspect of the track tension, in this paper first the static models of the robot and some important components for different motion states are established, so the constraints between the forces between the track and stairs, the track tension, and the driving forces of the driving components are obtained. Based on the above work, an optimal model of the track tension is established according to the robot performance influenced by the track tension. Then from simulations, the variation of the optimal controlled track tension during stair-climbing is obtained, and the simulation result provides a foundation for the robot to climb stairs with a good state of track tension.(3) In the realization of the autonomous movement, some theoretical analysis needs to be performed to make the wheelchair robot to have the ability of autonomous stair-climbing with considering the influence of the passenger.In order to make the robot to climb stairs automatically, in this paper first the robot control is divided into the control of the driving wheel and back flipper and the control of the front flipper according to the functions of the driving components. Then for the driving wheel and back flipper, a control scheme that can make the robot to move and transform automatically according to its position is established, and the real-time tip-over and slippage stability testing is also add to the control scheme. For the front flipper, a position and force control scheme that can make the robot to maintain a good state of track tension is established based on the geometric model of the robot and the optimal result of the track tension.In order to bring the passengers' influence into the control scheme, in this paper a method to calculate the pressure center of the passenger towards the chair is established with a pressure sensor system. Then by giving the relationship between the pressure center and some typical attitudes of the passenger, the identification of the passenger's attitude is realized to improve the autonomous control scheme. |
| 语种 | 中文 |
| 产权排序 | 1 |
| 页码 | 104页 |
| 分类号 | TP242 |
| 源URL | [http://ir.sia.ac.cn/handle/173321/14830]  |
| 专题 | 沈阳自动化研究所_机器人学研究室 |
| 推荐引用方式 GB/T 7714 | 于苏洋. 采用单节变形履带机构的越障轮椅机器人机理研究[D]. 中国科学院沈阳自动化研究所. 2013. |
入库方式： OAI收割
来源：沈阳自动化研究所
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