GDFs, smooth softmin distances to finite sets of arm-hand grasp configurations to handle changes in contact topology are presented, and a hysteretic contact-mode transition with a wrench-quality CBF that limits degradation of the realized force-closure margin relative to hold onset is combined.
Abstract
Mainstream plan-then-track approaches to multifingered grasp execution entail selecting a grasp, planning a collision-free trajectory, and tracking the resulting trajectory via a feedback controller. Pose-estimation error during execution or scene motion can invalidate this open-loop commitment and trigger replanning. We thus present Grasp Distance Fields (GDFs), smooth softmin distances to finite sets of arm-hand grasp configurations. Using their negative gradients as feedback, we jointly select and execute grasps without planning a trajectory. A CBF-CLF quadratic program (QP) enforces self-collision, workspace, object, and obstacle-clearance constraints, while its CLF slack quantifies obstruction of task progress. We bound the softmin approximation error by $\log N/\rho$ and prove forward invariance of the filtered safe set. To handle changes in contact topology, we combine a hysteretic contact-mode transition with a wrench-quality CBF that limits degradation of the realized force-closure margin relative to hold onset. Using our method, a fixed-base manipulator and a Unitree G1 equipped with the same underactuated hand grasp and lift 46 of 50 test objects amid clutter and moving obstacles. The realized grasps also retain a median 94% of their synthesized quality margin, and each QP solve requires 0.09 ms within a 20 ms control interval. Project page: www.clintonenwerem.com/gdf.
Language-guided robotic grasping has made significant progress in semantic understanding, but existing methods often rely on open-loop execution strategies and struggle to handle physical disturbances such as object collisions, target displacement, and transportation slippage. To address this problem, this paper proposes a stability-aware dynamic recovery mechanism, named SADR. Based on a multi-threaded decoupled architecture, SADR decouples semantic planning, target tracking, and execution control, and constructs a two-stage stability criterion through pre-closure displacement checking and post-closure force/current feedback verification. When target instability, missed grasping, or slippage is detected, the system performs local trajectory correction and re-grasping based on real-time tracking results, without restarting global semantic planning. Experiments in PyBullet show that SADR significantly improves the grasping success rate under high-density disturbance scenarios while reducing the average task completion time. This study provides an effective closed-loop recovery solution for improving the reliability of robotic grasping tasks in complex simulation environments.
Chuncheng Zhang, Lei Sun· 2026 IEEE 27th China Confere...· 0 citations
Neural-network-based grasp detection has achieved remarkable success in robotic manipulation due to its efficiency and generalization ability. However, detected poses are often not optimized, leading to undesired object motion or collisions during physical execution. This paper proposes a motion-aware refinement framework that minimizes estimated object motion while enforcing collision avoidance. The seven-dimensional pose is decomposed into approach direction, engagement depth, planar projection, and gripper opening width, enabling efficient and interpretable optimization in lower-dimensional subspaces. To evaluate grasp stability beyond conventional success metrics, we introduce the observed success rate (OSR) together with quantitative motion measurements including translation, rotation, and tilt. Real-robot experiments show that, for high-profile objects, the full pipeline improves the measured success rate (MSR) from 93.33% to 100% and OSR from 83.33% to 97.78%. It also reduces the mean translation from <inline-formula> <tex-math notation="LaTeX">$6.099{\,}mm$ </tex-math></inline-formula> to <inline-formula> <tex-math notation="LaTeX">$2.684{\,}mm$ </tex-math></inline-formula>, rotation from 3.732° to 1.344°, and tilt from <inline-formula> <tex-math notation="LaTeX">$4.417{\,}mm$ </tex-math></inline-formula> to <inline-formula> <tex-math notation="LaTeX">$1.313{\,}mm$ </tex-math></inline-formula>, while requiring <inline-formula> <tex-math notation="LaTeX">$0.82\pm 0.42{\,}s$ </tex-math></inline-formula> on average. For low-profile objects that cannot be detected by the baseline point-cloud-based planner, the full pipeline achieves 100% MSR and OSR.
Tian Tan, Redwan Alqasemi, R. Dubey· IEEE Access· 0 citations
The one-stage planner YOPO maps a single depth image and the robot state directly to a set of candidate trajectories, trained by backpropagating through differentiable trajectory costs. This yields dense, geometrically informative supervision, but inherits the pathologies of soft-constrained optimization: the safety cost competes with the smoothness and goal-reaching terms, is non-convex across homotopy classes, and the single-piece polynomial is limited in expressiveness. In this report, we summarize several effective modifications. We adopt a two-piece MINCO parameterization, trading time for smoothness without altering the trajectory's spatial profile. We further lift YOPO's multi-modal prediction to span distinct homotopy classes, treating each motion primitive as a homotopy anchor that confines the trajectory to a feasible basin - without explicit safe-flight-corridor construction or front-end search. For dynamic feasibility, we impose barrier penalties on velocity and acceleration together with a curvature-dependent speed limit whose gradient acts only on the velocity, producing an adaptive-speed behavior that decelerates in cluttered regions or sharp turns. We replace score regression with a ranking loss, preventing small score errors from reordering the candidate set. These yield richer trajectory representations, safer obstacle avoidance, and more direct flight paths.
Robot manipulators are commonly engineered around a decoupled motion-generation stack: a planner computes a collision-free path and a lower-level controller tracks the resulting reference. This separation is computationally convenient, but it can produce references that are difficult to execute under actuator limits, tracking error, model mismatch, and small obstacle clearances. We present CSymPlan, a certified symbolic planning and control framework for high-DOF manipulators with two complementary implementations: an offline implementation that precomputes certified reach-avoid feedback policies for known workspaces; and an online implementation that synthesizes or updates symbolic policies at runtime from changing task and perception information using parallelization. The offline implementation reduces the manipulator dynamics to a sampled perturbed double-integrator model in operational space through feedback linearization, treats torque-realization errors, modeling inaccuracies, and measurement uncertainty as bounded disturbances, and refines the synthesized symbolic policy to the Franka FR3 through a quantization--lookup--torque realization pipeline. The online implementation uses the same abstraction and refinement interface, but replaces the precomputed policy table with a runtime pFaces request--synthesis--execution loop. In randomized simulated benchmarks and perception-driven Franka FR3 experiments, both implementations complete reach-avoid tasks with zero safety violations; whenever no certified action exists, the robot holds, replans, or stops safely instead of executing an uncertified command.
Aditya Narendra, Ashok Kumar Saini, M. Anand et al.· 0 citations
A task-space receding-horizon controller that uses a short contact-consistent rollout to generate a terminal kinematic reference satisfying internal non-penetration constraints, then computes only the first input of a smooth minimum-acceleration transition toward that reference.
Bimanual manipulation enables complex tasks but introduces added complexity from the high number of degrees of freedom involved. When handling rigid objects, the relative transformation between the two end effectors must remain fixed throughout the motion, manifesting as a nonlinear equality constraint that confines the feasible configuration space to a measure-zero manifold and challenges conventional motion planners. We propose a fast bimanual motion planning pipeline that enforces this hard transformation constraint continuously along the entire path, using a leader-follower parameterization: the leader's configuration is treated as a free variable, while the follower's is determined via inverse kinematics to satisfy the constraint. We extensively evaluate the method in simulation across diverse environments, constraints and bimanual platforms, achieving 19.4x faster planning than prior work while guaranteeing continuous constraint satisfaction. Real-world experiments on a bimanual Kinova Gen3 setup, involving tray transport and elongated-object manipulation, validate direct transfer of planned trajectories to physical hardware.
Borna Paro, Luka Petrović, Ivan Markovic· 0 citations