A Novel Soft Gripper Design Integrating a Unilateral Fingernail-Like Mechanism for Grasping Flat Object
Wanyu MA, Xuyang Ren, Zheng Li
AI summary
Problem
Grasping flat objects flush on tables remains difficult due to unreliable height detection, collision risks with rigid grippers, and slippage from minimal contact area.
Approach
The authors design a hybrid pneumatic soft gripper featuring a unilateral rigid fingernail extension, paired with two geometrically tailored grasping strategies (Grip and Sweep) for reliable target generation.
Key results
- 92.7% average success rate across 15 flat objects, surpassing a commercial rigid gripper's 41%
- Linear grasping force scaling from 0.1 N to 3.2 N with consistent low-pressure actuation
- Accurate arc-trajectory modeling (R² > 0.97) enabling precise grasp pose generation
- Real-time operation (<1 second per grasp) across household, industrial, and medical flat items
Why it matters
Provides a low-cost, compliant solution for reliable robotic manipulation of flush flat objects in domestic, industrial, and medical settings without expensive high-precision sensing.
Abstract
The grasping capabilities of robotic arms have been extensively studied by researchers in terms of accuracy, flexibility, and versatility, enabling robots to perform various tasks in domestic, industrial, and medical scenarios. However, grasping flat objects has remained a significant challenge and is often overlooked as a limiting case in robotic manipulation. To address this highly difficult task, this paper proposes a novel gripper design that combines a pneumatic soft gripper with a unilateral fingernail structure. We evaluate two grasping strategies and corresponding target generation methods tailored for this design. The proposed system significantly improves the success rate of stably grasping flat objects that lie flush on tables. Moreover, its soft interaction with the table surface reduces the need for highly precise object-table height detection, thereby saving computational time and cost. Finally, we conduct experimental tests on various common flat objects, validating the effectiveness of both the gripper design and the grasping strategies.