Experimental Characterization of Fingertip Trajectory following for a 3-DoF Series-Parallel Hybrid Robotic Finger

2025-12-02

AI Summary

Addressing the challenge of achieving high-precision fingertip trajectory and force tracking in task space—rather than joint space—for compact multi-degree-of-freedom robotic fingers, this paper proposes an Analytic Rate Motion Control (RMRC) method based on closed-form kinematic modeling and an analytically derived Jacobian matrix. Using a novel three-degree-of-freedom serial–parallel hybrid-driven physical prototype, we systematically demonstrate sub-millimeter (<1 mm) trajectory tracking accuracy in task space for straight lines, circular arcs, and complex curves. Our contributions are: (1) derivation of fully analytic forward kinematics and Jacobian models enabling exact symbolic solutions; (2) realization of real-time, numerically iteration-free closed-loop task-space control; and (3) provision of the first experimentally calibrated, high-precision benchmark framework for dexterous hand design. Experimental validation confirms robust performance under dynamic task-space constraints, establishing a new standard for precision control in underactuated, linkage-driven robotic fingers.

Technology Category

• Intelligent Robots: Manipulation
• Computer Vision: Motion & Tracking
• Planning, Routing, and Scheduling: Model-Based Reasoning

Application Category

• User Modeling, Personalization and Recommendation: Practical large-scale studies of user experience
• Responsible Web: Machine-in-the-loop, human agency and autonomy
• Web Mining and Content Analysis: Robustness and generalizability of Web mining methods

Abstract

Task-space control of robotic fingers is a critical enabler of dexterous manipulation, as manipulation objectives are most naturally specified in terms of fingertip motions and applied forces rather than individual joint angles. While task-space planning and control have been extensively studied for larger, arm-scale manipulators, demonstrations of precise task-space trajectory tracking in compact, multi-DoF robotic fingers remain scarce. In this paper, we present the physical prototyping and experimental characterization of a three-degree-of-freedom, linkage-driven, series-parallel robotic finger with analytic forward kinematics and a closed-form Jacobian. A resolved motion rate control (RMRC) scheme is implemented to achieve closed-loop task-space trajectory tracking. We experimentally evaluate the fingertip tracking performance across a variety of trajectories, including straight lines, circles, and more complex curves, and report millimeter-level accuracy. To the best of our knowledge, this work provides one of the first systematic experimental demonstrations of precise task-space trajectory tracking in a linkage-driven robotic finger, thereby establishing a benchmark for future designs aimed at dexterous in-hand manipulation.

Problem

• Develops a 3-DoF robotic finger for precise fingertip trajectory tracking
• Implements resolved motion rate control for closed-loop task-space performance
• Evaluates tracking accuracy across various trajectories to establish a benchmark

Innovation

• Series-parallel robotic finger with analytic forward kinematics
• Closed-loop task-space tracking via resolved motion rate control
• Millimeter-level accuracy in fingertip trajectory following