【作者】 张大伟；

【导师】 宋申民；

【作者基本信息】 哈尔滨工业大学 ， 控制理论与控制工程， 2006， 硕士

【摘要】 机器人视觉伺服系统由视觉传感器向控制器提供外部信息,调整机器人的位置和姿态。当前机器人视觉伺服研究的主要内容可以归纳为视觉伺服系统结构、快速有效的图像处理算法以及视觉伺服控制器的设计等几个主要方面。论文主要解决Camera-in-Hand机械臂系统的控制问题,目的是控制执行器的运动,以使静止或者运动目标物体的投影图像在摄像头捕捉的画面中位于一个期望的位置。本文首先使用了模糊自适应控制方法。此种方法用构建的自适应模糊系统在线调整参数逼近系统未知参数模型,然后用一个自适应的补偿项补偿模糊系统的逼近误差,使系统稳定。其次将模糊自适应控制与滑模变结构控制结合起来,使用了自适应模糊滑模控制方法。这种方法用构建的自适应模糊系统在线逼近系统未知参数模型,用滑模控制项保证系统的稳定性,同时在线自适应调整滑模控制项的增益系数,一方面使滑模控制项可以补偿模糊系统造成的逼近误差,另一方面可以在一定程度上减轻滑模控制方法导致的抖振现象的程度。论文最后针对滑模变结构控制中存在的固有的抖振问题,提出了两种改进的自适应模糊滑模控制方法。一种方法是用一个自适应在线调整参数的自适应模糊系统逼近模糊滑模控制中的符号函数项,从而能够使进入稳定区域滑模面的系统平滑,避免了抖振现象;另一种方法是用一个饱和函数代替符号函数,使进入稳定滑模面区域的系统在滑模面附近的一个带状区域内运动,在带状区域的边界,控制量是由符号函数决定的,能够控制系统不运动出带状区域,在带状区域内,控制量是由线性函数决定的,其幅值较小,控制作用较弱,但是能够明显的消除系统的抖振现象。更多还原

【Abstract】 The structure of robot visual servoing system is that controller receives external information from visual sensor, then the controller adjusts position and pose of the robot. Recently the main study of visual servoing system is the structure of visual servoing system, the arithmetic of fast and effective image processing and the design of visual servoing system controller.In this paper, the control problem of camera-in-hand robot system is solved. The aim of this approach is to move the robot arm in such a way that the image of the static or dynamic objects attains the desired locations in the image plane. In this paper, adaptive fuzzy control is used. An adaptive fuzzy system is designed to approximate the system whose parameters are unknown. Then an adaptive compensator is used to compensate the error which caused by the fuzzy system. So that the system can be stable.After that, adaptive fuzzy sliding mode control is used, which is composed of adaptive fuzzy control and variable structure control based on sliding mode. This approach uses an adaptive fuzzy system designed to approximate the system whose parameters are unknown. Then sliding mode control part is used to guarantee the stability of the system, and it tunes its gain on-line at the same time. On the one hand the adaptive gain can compensate the error which caused by the fuzzy system, on the other hand it can alleviate the chattering caused by the sliding mode control part to a certain extent.At last, two kinds of advanced adaptive fuzzy sliding mode control is proposed for the chattering existing in sliding mode control. The first one uses an adaptive fuzzy system tuning its parameters on-line to approximate the sign function part in the fuzzy sliding mode control. Then the system can be smoothed as it gets into the sliding mode plane, in the other word it avoids the chattering. The second one uses a sat function to replace the sign function. So that the system moves in a band area as it gets into the stable sliding mode plane. At the edge of the band area, the control is designed by the sign function to limit the system moves in the band area. In the band area, the control is designed by a line function, whose gain is small and effect is not strong. But the control can avoid the chattering powerfully.更多还原