This paper introduces a method for 6D pose tracking and control of multiple objects during non-prehensile manipulation by a robot. The tracking system estimates objects' poses by integrating physics predictions, derived from robotic joint state information, with visual inputs from an RGB-D camera. Specifically, the methodology is based on particle filtering, which fuses control information from the robot as an input for each particle movement and with real-time camera observations to track the pose of objects. Comparative analyses reveal that this physics-based approach substantially improves pose tracking accuracy over baseline methods that rely solely on visual data, particularly during manipulation in clutter, where occlusions are a frequent problem. The tracking system is integrated with a model predictive control approach which shows that the probabilistic nature of our tracking system can help robust manipulation planning and control of multiple objects in clutter, even under heavy occlusions. Associated code and data available at:https://github.com/ZisongXu/PBPF.

Trajectory optimisation methods for robotic motion planning often require the use of first order derivatives of the dynamics of the system with respect to the states and controls of the system. Particularly when multi-contact dynamics are present, these derivatives are often numerically approximated by a method such as finite-differencing. Finite-differencing whilst using an expensive physics simulator is usually the bottleneck in these trajectory optimisation algorithms. Since these dynamics derivatives do not change substantially over certain time inter-vals, we propose that trajectory optimisers can compute the dy-namics derivatives less often and then interpolate approximations to the derivatives in between calculated derivatives, gaining a sig-nificant speed up for overall optimisation time with no observable degradation in the generated behaviour. We investigate different methods of interpolating approximations as well as propose an adaptive method to detect when to compute the derivatives with finite-differencing. We find a speed-up of planning times on average by 60% in a contact-based manipulation task.

Planning for deformable object manipulation has been a challenge for a long time in robotics due to its high computational cost. In this work, we propose to reduce this cost by reducing the number of pick points on a deformable object in the action space. We do this by identifying a small number of key particles that are sufficient as pick points to reach a given goal state. We find these key particles through a geometric model simplification process, which finds the minimal geometric model that still enables a good approximation of the original model at the goal state. We present an implementation of this general approach for 1-D linear deformable objects (e.g., ropes) that uses a piece-wise line fitted model, and for 2-D flat deformable objects (e.g., cloth) that uses a mesh simplified model. We conducted simulation experiments on ropes and cloths, which demonstrate the effectiveness of the proposed method. Finally, the planned paths are executed in a real-world setting for two cloth folding tasks.

We present a predictive system for non-prehensile, physics-based motion planning in clutter with a human-in-the-loop. Recent shared-autonomous systems present motion planning performance improvements when high-level reasoning is provided by a human. Humans are usually good at quickly identifying high-level actions in high-dimensional spaces, and robots are good at converting high-level actions into valid robot trajectories. In this paper, we present a novel framework that permits a single human operator to effectively guide a fleet of robots in a virtual warehouse. The robots are tackling the problem of Reaching Through Clutter (RTC), where they are reaching onto cluttered shelves to grasp a goal object while pushing other obstacles out of the way. We exploit information from the motion planning algorithm to predict which robot requires human help the most and assign that robot to the human. With twenty virtual robots and a single human-operator, the results suggest that this approach improves the system's overall performance compared to a baseline with no predictions. The results also show that there is a cap on how many robots can effectively be guided simultaneously by a single human operator.

We propose a human-operator guided planning approach to pushing-based manipulation in clutter. Most recent approaches to manipulation in clutter employs randomized planning. The problem, however, remains a challenging one where the planning times are still in the order of tens of seconds or minutes, and the success rates are low for difficult instances of the problem. We build on these control-based randomized planning approaches, but we investigate using them in conjunction with human-operator input. In our framework, the human operator supplies a high-level plan, in the form of an ordered sequence of objects and their approximate goal positions. We present experiments in simulation and on a real robotic setup, where we compare the success rate and planning times of our human-in-the-loop approach with fully autonomous sampling-based planners. We show that with a minimal amount of human input, the low-level planner can solve the problem faster and with higher success rates.