【作者】 刘大亮；

【导师】 孙汉旭； 贾庆轩；

【作者基本信息】 北京邮电大学 ， 机械电子工程， 2009， 博士

【摘要】 球形移动机器人具有运动灵活的优点,且在运动中不存在翻仰问题。因此在工业、民用、国防以及空间探索等领域具有广泛的应用前景。但是球形移动机器人与地面之间具有近似点接触的特点,导致运动分析与控制技术成为球形移动机器人研究的关键问题,并且一直没有得到有效地解决,阻碍了球形移动机器人的进一步研究和应用。因此,本论文深入地研究了一种球形移动机器人的运动分析与控制技术问题。主要的研究工作如下:首先,基于欧拉——拉格朗日方法建立球形移动机器人的动力学模型,利用坐标变换和输入控制变换对模型进行降阶和标准型处理,并设计双回路线性运动控制策略;提出球形移动机器人的动态平衡问题,分别建立球壳质量分布均匀和非均匀条件下的平面动力学模型,利用部分线性化方法将模型分别变换为非“三角”正则形式的和“三角”正则形式的级联非线性模型,并设计指数稳定的动态平衡控制策略;分别对提出的运动控制和平衡控制策略进行稳定性分析、仿真和实验研究。其次,将球形移动机器人分别简化为“球壳——重摆”模型和“球壳——框架”模型,建立两者的动力学微分方程,并通过求解微分方程的近似解研究驱动机构在两个驱动轴方向上的运动特性;从鲁棒控制的角度,将驱动机构对球壳的耦合作用假设为系统的不确定项后,建立了球形移动机器人的不确定性动力学模型;应用滑模变结构技术设计鲁棒运动控制策略,并进行控制策略的稳定性分析、仿真和实验研究。再次,利用微分几何的方法研究球形移动机器人运动学模型的可控性,利用坐标变换对模型进行标准型处理,并设计指数稳定的非线性姿态控制策略;基于球形移动机器人的运动学模型和鲁棒运动控制策略提出基于曲率的路径跟踪策略;分别对提出的姿态控制和路径跟踪控制策略进行稳定性分析、仿真和实验研究。在理论研究成果的基础上,研制球形移动机器人的嵌入式控制系统,分析系统的可能性故障,并针对故障提出球形移动机器人的冗余容错策略;研制高可靠性的冗余双备份伺服控制系统,并进行实验研究。最后,研究基于多传感器(惯性测量装置、光电编码器、激光测距仪以及视觉传感器)融合技术的球形移动机器人自主运动控制策略;分别建立里程计模型和激光测距仪模型,从不确定性信息描述的角度分析模型的误差;对提出的自主运动控制策略进行实验研究。更多还原

【Abstract】 The advantage of the spherical mobile robot includes high maneuverability, and that the robot can resume stability even if a collision happened with the other obstacles. So it is very suitable to be used in those environments, such as industrial building, civil application, defense construction and space exploration domain. But, till now, because of the feature of the point contact between the spherical shell and the ground, there are no effective methods that can sovle the problems about the motion analysis and control techonology of a spherical mobile robot, which prevents further research and application of the robot. So, in order to sovle these problems, this thesis discusses deeply the motion analysis and control techonology of the robot. The following aspects are contained in this thesis.Firstly, based on the Euler-Lagrangian method, the dynamics model of the spherical mobile robot was developed, treated by reduced-order and transformed to normal nonlinear system using coordinate and input control transformation. Then, the double loop linear motion control strategy was designed. The problem of the dynamic equilibrium was proposed, and the dynamics models of the planar motion were developed in the case of uniform and uneven of the shell’s mass distribution, respectively. Then, using the partial linearization method, both of the two models were transformed to cascade nonlinear systems with non-triangular and triangular normal form, respectively. Moreover, the dynamic balance controllers with exponential stability were developed. The stability analysis, simulation and test verification were finished for the motion control and balance control strategies.Secondly, the spherical mobile robot was simplified as the "spheroid-pendulum" and the "spheroid-frame" model, and their dynamics differential equations were developed, respectively. The motion characteristic of the drive mechanism along the two drive shafts was discussed by solving the approximate solutions of the differential equations. For the sake of robust control, the uncertainty dynamics model of spherical mobile robot was developed while the coupling effect of the drive mechanism was regarded as the interference items of the spheroid motion. Then, the robust motion controllers were designed, using the slide-mode variable structure method, and the stability analysis, simulation and test verification were finished for the control strategies.Thirdly, the kinemics model’s controllability of the spherical mobile robot was analyzed using the theories of differential geometry, and the kinematics model was transformed to normal form. Then, the nonlinear controller was proposed for the attitude control. Based on the robust motion control and the kinemics model, the control strategy of line path following based on the curvature of the shell was proposed. Moreover, the stability analysis, simulation and test verification were finished for the attitude control and path following control strategies.Based on the results of the theoretical research above, the embedded control system for the spherical mobile robot was designed. The possible faults of the system were discussed in detailed, and the fault-tolerant strategies of the control system were proposed for faults. Moreover, the dual-redundant servo control system of the motors was developed, and test verification was finished.Finally, based on the sensor fusion technology including the gyroscope, optical encoders, laser rangefinders and vision sensor, the strategies of autonomous motion control was developed. The models of the odometer and the laser rangefinders were developed, respectively, and the errors of the models were analyzed from the view of the uncertainty information description. Moreover, the test verification of the presented motion control was finished.更多还原