A Robust Approach to Control Robot Manipulators by Fusing Visual and Force Information

In this paper, a method to combine visual and force information using the information obtained from the movement flow-based visual servoing system is proposed. This method allows not only to achieve a given desired position but also to specify the trajectory that the robot will follow from its initial position to its final one in the 3D space. This paper also extends the visual servoing system in order to increase the robustness when errors in the camera calibration parameters appear. Experiments using an eye-in-hand robotic system demonstrate the correct behaviour when important errors exist in the camera intrinsic parameters. After the description of this strategy, we then describe its application to an insertion task to be performed by the robotic system in which the joint use of visual and force information is required. To combine both sensorial systems, a position-based impedancecontrol system is implemented, which modifies the trajectory generated by the visual system depending on the robot’s interaction with its setting. This modification is performed without knowledge of the exact camera calibration parameters. Furthermore, the visual-force approach based on impedance control does not require having previous knowledge about the contact geometry. keywords—Movement flow, force control, visual-force control, impedance control, 2D visual servoing, intrinsics-free control. Categories (7), (8).