How to reduce uncertainty in object pose estimation under complex contacts is crucial to autonomous robotic manipulation and assembly. In this paper, we introduce an approach through forecasting contact force from simulated complex contacts with calibration based on real force sensing. A constraint-based haptic simulation algorithm is used with sphere-tree representation of contacting objects to compute contact poses and forces, and through matching the computed forces to measured real force data via a regression model, the least-uncertain estimate of the relative contact pose is obtained. Our approach can handle multi-region complex contacts and does not make any assumption about contact types or contact locations. It also does not have restriction on object shapes. We have applied the force forecast approach to reducing uncertainty in estimating object poses in challenging peg-in-hole robotic assembly tasks and demonstrate the effectiveness of the approach by successful completion of contact-rich two-pin and three-pin real peg-in-hole assembly tasks with complex shapes of pins and holes.

This paper introduces a reinforcement learning algorithm with robot manipulation to learn an arbitrary object's center of mass whose physical material composition is unknown. Robot learning is through manipulation of the object in a sequence of actions. The effectiveness of the algorithm is demonstrated in simulation to locate the centers of mass of rocks with complex shapes, with even or uneven mass distributions, and confirmed by vertically stacking the rocks along their learned centers of mass both in simulation and in real experiments.

This paper introduces conflict resolution in task-constrained real-time adaptive motion planning (RAMP) to enable a robot manipulator performing tasks in an environment with dynamically unknown obstacles. The method continuously improves and maintains diverse task constrained as well as unconstrained robot trajectories to allow the manipulator switching to a better trajectory at any time and seamlessly resolving conflicts between satisfying task constraints and avoiding dynamically unknown obstacles. If dynamic obstacles block all available task-constrained trajectories, the algorithm allows the manipulator to change goals on the fly to be free of task constraints and resume the task whenever there is a collision-free, task-constrained trajectory. The method is validated in different dynamic environments with different task constraints in both simulation and real-world experiments.

It is important to enable a robot to manipulate a target object that has no 3-D model information and is situated in an environment with other unknown objects nearby. This poses an open problem of how to combine perception and manipulation to enable the robot to build an appearance-based model of the target object on the spot to facilitate further manipulation of the object while avoiding the other unknown obstacles in the way. In this paper, we introduce an approach to enable a continuum manipulator, which is apt to maneuver through a crowded environment, to gradually build a 3-D surface model of the target object by moving an RGB-D sensor around the object while also detecting and avoiding surrounding unknown obstacles. Our approach interleaves perception and manipulation such that perception guides the manipulator movement, which in turn allows more perception of the target object for object model building and further manipulator motion. Our approach is characterized by a progressive strategy to register RGB-D images of the target object to build and extend a partial model of the object and the corresponding motion planning strategy for the continuum robot to carry out model building and avoid obstacles at the same time. To demonstrate the effectiveness of our approach, experiments on progressive model building of real objects from real RGB-D images are conducted, where a simulated continuum robot plans and executes its motion to carry the RGB-D camera around a target object for taking those images in an augmented reality setting.

We introduce a novel approach to shape-based object classification and recognition through the use of a continuum manipulator. Noticing the fact that when a continuum manipulator wraps around an object in a whole-arm grasping, its own shape is indicative of the shape of the object, our approach enables learning and recognition of object classes based on the shapes of continuum wraps. It offers the following advantages: (1) recognition of objects that are not easily detected by vision, such as transparent objects, and (2) highly efficient recognition of such objects of varied sizes due to high-level and rich shape information in each wrap, unlike recognition based on tactile sensing via conventional grasping. Simulation and experiments demonstrate the effectiveness of our approach.