Terrain Modeling and Following Using a Compliant Manipulator for Humanitarian Demining Applications

Operations with flexible, compliant manipulators over large workspaces relative to the manipulator are complicated by sensor noise, vibration, and measurement bias. These difficulties are compounded by unstructured environments, such as those encountered in humanitarian demining. By taking advantage of the static structure of the terrain and the manipulator’s fundamental mechanical characteristics, a series of adaptive corrections and filters refine noisy topographical measurements. These filters along with a shaped actuation scheme can generate smooth and well-controlled trajectories. Experimental testing was performed on a field robot with a compliant, 3 m long-reach hybrid manipulator and a stereo vision system for terrain sensing. The proposed method provides a vertical tracking precision of ±5 mm on a variety of ground clearings, with scanning speeds of up to 0.5 m/s. As such, it can agilely move the attached sensor(s) through precise scanning trajectories that are very close to the ground. This method improves overall detection and generation of precise maps of suspected mine locations.