Stereo Image-Based Visual Servoing towards Feature-Based Grasping

This paper presents an image-based visual ser- voing scheme that can control robotic manipulators in 3D space using 2D stereo images without needing to perform stereo reconstruction. We use a stereo camera in an eye-to- hand configuration for controlling the robot to reach target positions by directly mapping image space errors to joint space actuation. We achieve convergence without a-priori knowledge of the target object, a reference 2D image, or 3D data. By doing so, we can reach targets in unstructured environments using high-resolution RGB images instead of utilizing relatively noisy depth data. We conduct several experiments on two different physical robots. The Panda 7DOF arm grasps a static target in 3D space, grasps a pitcher handle, and picks and places a box by determining the approach angle using 2D image features, demonstrating that this algorithm can be used for grasping practical objects in 3D space using only 2D image features for feedback. Our second platform, the Atlas humanoid robot, reaches a target from an unknown starting configuration, demonstrating that this controller achieves convergence to a target, even with the uncertainties introduced by walking to a new location. We believe that this algorithm is a step towards enabling intuitive interfaces that allow a user to initiate a grasp on an object by specifying a grasping point in a 2D image.