A Novel Robot Hand with Hoeckens Linkages and Soft Phalanges for Scooping and Self-Adaptive Grasping in Environmental Constraints

2025-10-15

AI Summary

To address dexterous manipulation under complex environmental constraints, this paper proposes Hockens-A Hand—a single-actuator, tri-modal adaptive robotic hand. Methodologically, it integrates a Hoeckens linkage (for vertical compliance), dual parallelogram linkages (to ensure linear fingertip contact), and a four-bar amplification mechanism (to enhance motion transmission efficiency), forming an underactuated architecture. A passive mechanical intelligence switching mechanism enables natural, mode-free transitions among parallel pinch, asymmetric scoop, and enveloping grasp modalities. Grid-textured silicone phalanges further improve enveloping adaptability. Experimental evaluation of a 3D-printed prototype demonstrates stable execution of all three grasp types across multi-constrained scenarios. Measured grasping forces align closely with those predicted by dynamic modeling and simulation, validating both structural efficacy and practical applicability.

Technology Category

• Intelligent Robots: Manipulation
• Search and Optimization: Sampling/Simulation-based Search
• Humans and AI: Interaction Techniques and Devices

Application Category

• Graph Algorithms and Modeling for the Web: Efficient manipulation of static and dynamic Web-related graphs
• Responsible Web: Machine-in-the-loop, human agency and autonomy
• Economics, Online Markets and Human Computation: Incentives in network design for Web infrastructures and ecosystems

Abstract

This paper presents a novel underactuated adaptive robotic hand, Hockens-A Hand, which integrates the Hoeckens mechanism, a double-parallelogram linkage, and a specialized four-bar linkage to achieve three adaptive grasping modes: parallel pinching, asymmetric scooping, and enveloping grasping. Hockens-A Hand requires only a single linear actuator, leveraging passive mechanical intelligence to ensure adaptability and compliance in unstructured environments. Specifically, the vertical motion of the Hoeckens mechanism introduces compliance, the double-parallelogram linkage ensures line contact at the fingertip, and the four-bar amplification system enables natural transitions between different grasping modes. Additionally, the inclusion of a mesh-textured silicone phalanx further enhances the ability to envelop objects of various shapes and sizes. This study employs detailed kinematic analysis to optimize the push angle and design the linkage lengths for optimal performance. Simulations validated the design by analyzing the fingertip motion and ensuring smooth transitions between grasping modes. Furthermore, the grasping force was analyzed using power equations to enhance the understanding of the system's performance.Experimental validation using a 3D-printed prototype demonstrates the three grasping modes of the hand in various scenarios under environmental constraints, verifying its grasping stability and broad applicability.

Problem

• Develops adaptive robotic hand for environmental constraint grasping
• Achieves three grasping modes with single linear actuator
• Enhances object enveloping through kinematic optimization and compliance

Innovation

• Uses Hoeckens mechanism for compliance and adaptability
• Integrates double-parallelogram linkage for line contact
• Employs four-bar system for natural grasping transitions