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Robust Planning for In-Hand Manipulation with Uncertain Extrinsic Contacts


Concetti Chiave
A robust planning framework for in-hand manipulation tasks that maintains desired contact modes despite uncertainties in kinematic and physical parameters.
Sintesi

The paper presents a robust in-hand manipulation framework that can handle complex contact interactions and uncertainties in the system parameters. The key components are:

  1. In-Gripper Mechanics Model:

    • Predicts the object's in-hand slip and motion based on the contact parameters and gripper motion.
    • Computes a "naïve" motion cone that maintains the desired contact mode assuming precise environment parameters.
  2. Robust Planning Method:

    • Refines the motion cone to account for uncertainties in parameters like contact position, object dimensions, etc.
    • Generates a robust trajectory that minimizes in-hand object slip and maintains the desired contact mode despite parametric errors.

The proposed framework is verified through real-world experiments on a robotic system. It is shown to be effective in maintaining contact mode and successfully executing in-hand manipulation tasks, outperforming a naïve planning approach that does not consider uncertainties.

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Statistiche
The paper provides the following key figures and metrics: Coefficient of friction between the object and gripper fingers: μg = 0.4 Grasping force: Ng = 20 N Radius of the gripper's circular patch contact: r = 0.01 m Object mass: m = 0.085 kg Uncertainty ranges: Grasping point location: ±3 mm Object center of mass location: ±3 mm Object bottom length: ±2 mm
Citazioni
"Maintaining external contact mode is crucial to the success of contact-rich in-hand manipulation tasks (for example see Fig. 1). Several previous works have reported that unexpected contact mode transition can lead to task failure." "The generated gripper trajectory should prevent unexpected contact mode transition against parametric uncertainties, especially kinematic parameters such as contact position and object dimensions."

Approfondimenti chiave tratti da

by Boyuan Liang... alle arxiv.org 03-29-2024

https://arxiv.org/pdf/2403.18960.pdf
Robust In-Hand Manipulation with Extrinsic Contacts

Domande più approfondite

How can the proposed robust planning framework be extended to handle dynamic in-hand manipulation tasks with more complex contact interactions?

The proposed robust planning framework can be extended to handle dynamic in-hand manipulation tasks with more complex contact interactions by incorporating real-time feedback mechanisms. By integrating tactile sensors or force sensors into the system, the robot can adapt its motion based on the actual contact forces experienced during manipulation. This feedback loop can enable the robot to adjust its trajectory on the fly, ensuring stable contact with the environment even in dynamic scenarios. Furthermore, the framework can be enhanced to include predictive modeling of contact interactions. By leveraging machine learning algorithms to predict how the object will behave under different contact conditions, the robot can proactively plan its motions to maintain stable contact throughout the manipulation task. This predictive capability can help the robot anticipate and mitigate potential failures before they occur. Additionally, the framework can be extended to handle multi-fingered grasping scenarios, where each finger may have different contact points and forces. By modeling the interactions between multiple contact points and coordinating the motions of each finger, the robot can achieve more complex manipulation tasks that require coordinated movements and precise control over contact forces.

What are the potential limitations of the current approach, and how can it be improved to handle larger uncertainty ranges or higher-dimensional parameter spaces?

One potential limitation of the current approach is the assumption of linear cone approximation for the motion cone, which may not accurately capture the curvature of the feasible motion space in scenarios with larger uncertainty ranges or higher-dimensional parameter spaces. To address this limitation, the framework can be improved by implementing more sophisticated optimization techniques, such as nonlinear optimization or convex optimization, to compute the robust motion cone. These advanced optimization methods can better handle the nonlinearity and complexity of the motion space, enabling more accurate and reliable planning in scenarios with larger uncertainty ranges. Another limitation is the reliance on predefined uncertainty ranges for each parameter, which may not fully capture the true variability in the system. To improve this aspect, the framework can be enhanced with adaptive uncertainty modeling techniques that dynamically adjust the uncertainty ranges based on real-time sensor feedback. By continuously updating the uncertainty estimates during manipulation, the robot can adapt to changing conditions and optimize its motions accordingly. Furthermore, the current approach may struggle with high-dimensional parameter spaces due to the computational complexity of exploring all possible combinations of parameters. To overcome this limitation, the framework can benefit from dimensionality reduction techniques, such as principal component analysis or feature selection, to reduce the effective dimensionality of the parameter space. By focusing on the most relevant parameters and their interactions, the planning process can be streamlined and made more efficient.

What other types of robotic manipulation tasks could benefit from the principles of robust planning with uncertain extrinsic contacts, and how could the framework be adapted to those domains?

Robotic manipulation tasks that involve delicate object handling, such as pick-and-place operations in manufacturing or assembly tasks in confined spaces, could benefit from the principles of robust planning with uncertain extrinsic contacts. The framework can be adapted to these domains by incorporating constraints specific to the task requirements, such as object fragility, workspace limitations, or safety considerations. For pick-and-place operations, the framework can be extended to optimize grasping strategies that minimize object slippage and ensure secure handling throughout the manipulation process. By considering uncertainties in object properties, gripper dynamics, and environmental conditions, the robot can plan robust grasping and release motions that account for potential variations in the task environment. In assembly tasks, where precise alignment and coordination are crucial, the framework can be tailored to handle multi-step manipulation sequences with varying contact modes. By modeling the contact interactions at each assembly step and optimizing the overall manipulation plan, the robot can achieve accurate and reliable assembly processes even in the presence of uncertainties. Moreover, in tasks involving human-robot collaboration, such as shared grasping or cooperative manipulation, the framework can be adapted to incorporate human intent recognition and feedback mechanisms. By integrating human input into the planning process, the robot can adapt its motions to align with the human operator's intentions, enabling seamless and efficient collaboration in complex manipulation tasks.
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