A Study on Advanced Visual Servo Systems Design via Nonlinear Model Predictive Control

利用视觉反馈对机械系统进行运动控制是人类的一项基本能力。视觉反馈控制是非线性控制理论与几何力学、图像处理等学科交叉的一门重要学科。本文从非线性控制理论的角度研究了机器人视觉反馈控制问题，首先将机器人相对刚体运动的三维视觉反馈控制问题看作是机器人相对于图像特征位置的镇定问题。通过使用SE（3）的表示，目标物体和摄像机之间的相对刚体运动动力学已被导出。利用3-D视觉反馈系统的无源性和旋转矩阵的性质，设计了视觉反馈控制器，保证了系统在Lyapunov意义下的渐近稳定性。其次，本文的主要贡献是利用非线性模型预测控制设计和分析了视觉反馈控制。基于控制李雅普诺夫函数和相应的反馈控制律，提出了三维视觉反馈系统的镇定非线性模型预测控制方案。所提出的计划已采用的成本函数作为李雅普诺夫函数建立稳定性。

Motion control of the mechanical systems with visual feedback is a basic ability of human being. Appli cations that have been proposed widely span manufacturing, car steering and so on. Moreover, the visual feedback control is an important discipline that lies at the intersection between nonlinear control theory and geometric framework of the mechanics and image processing. This research deals with the visual feedback control of robotic manipulators in nonlinear control theoretical aspect.Firstly, the 3-D visual feedback control problem of the relative rigid body motion is considered as the stabilization problem with respect to the image feature position. By using the representation of SE(3), the relative rigid body motion dynamics between the target object and the camera has been derived. The passivity of the 3-D visual feedback system and the rotational matrix property derive the visual feedback controller to guarantee the asymptotic stability, in the Lyapunov sense.Next, the principal contribution of this research is the design and analysis of the isual feedback control via the nonlinear model predictive control. Based on the control Lyapunov function and the corresponding feedback control law, the stabilizing nonlinear model predictive control scheme for the 3-D visual feedback system has been proposed. The proposed scheme has employed the cost function as a Lyapunov function for establishing stability.