To make the controller implementation easier and to enhance the system robustness and control performance in the presence of the camera parameter uncertainties, it is very desired to develop vision-based control approaches without any offline or online camera calibration. In this article, we propose a new calibration-free image-based trajectory tracking control scheme for nonholonomic mobile robots with a truly uncalibrated fixed camera. By developing a novel camera-parameter-independent kinematic model, both offline and online camera calibration can be avoided in the proposed scheme, and any knowledge of the camera is not needed in the controller design. The proposed trajectory tracking control scheme can guarantee exponential convergence of the image position and velocity tracking errors. To illustrate the performance of the proposed scheme, experimental results are provided in this article. Note to Practitioners —This article was motivated by the vision-based motion control problem of mobile robots in uncalibrated environments. Existing vision-based motion control approaches for nonholonomic mobile robots generally depend on offline precise/coarse or online numerical/adaptive calibration of the camera intrinsic and extrinsic parameters and require precise or coarse knowledge of the camera in their implementation. This article presents a novel calibration-free image-based trajectory tracking control scheme, which can be implemented easily in real environments without any offline or online calibration of the camera parameters and can be used to efficiently control the motion of nonholonomic mobile robots with an arbitrarily placed and truly unknown overhead camera. Experimental results show that the proposed scheme can achieve satisfactory trajectory tracking control performance despite the lack of any knowledge about the camera intrinsic and extrinsic parameters and the presence of unknown camera lens distortions, and hence, can provide a simple but efficient solution to the vision-based motion control problem of nonholonomic mobile robots.

中文翻译：

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带有高架摄像机的移动机器人的基于图像的无标定轨迹跟踪控制

为了在存在摄像机参数不确定性的情况下简化控制器的实现并增强系统的鲁棒性和控制性能，非常需要开发基于视觉的控制方法，而无需进行任何离线或在线摄像机校准。在本文中，我们为带有完整未校准固定摄像头的非完整移动机器人提出了一种新的免校准基于图像的轨迹跟踪控制方案。通过开发一种新颖的与摄像机参数无关的运动学模型，可以在提出的方案中避免离线和在线摄像机校准，并且在控制器设计中不需要任何摄像机知识。所提出的轨迹跟踪控制方案可以保证图像位置和速度跟踪误差的指数收敛。为了说明提议的方案的性能，执业者注意 —本文受到未校准环境中移动机器人基于视觉的运动控制问题的启发。用于非完整移动机器人的基于视觉的现有运动控制方法通常依赖于照相机固有和外部参数的离线精确/粗略或在线数值/自适应校准，并且在实现过程中需要照相机的精确或粗略知识。本文提出了一种新颖的基于图像的无标定轨迹跟踪控制方案，该方案可以在真实环境中轻松实现，而无需对摄像机参数进行任何离线或在线标定，并且可以通过任意方式有效地控制非完整移动机器人的运动放置且真正未知的高架摄像机。