Multimodal grasping has emerged as a promising strategy to enhance the grasping diversity of grippers in response to the rapid expansion of application scenarios. Among various designs, the pinch-suction hybrid mechanism and the soft-rigid hybrid structure have proved to be two practical strategies to achieve multimodality. However, existing research on these two strategies still lacks simple and effective collaborative mechanisms to fully leverage the advantages of each mode while ensuring mutual noninterference. In this article, we propose a pinch-suction and soft-rigid hybrid multimodal gripper (HMG), integrating four operating modes into a compact structure. Two simple and effective collaborative mechanisms are introduced to coordinate between pinch and suction operation and between soft and rigid components, respectively. Through the collaboration of different modes, the HMG exhibits a competitive grasping diversity across four aspects, including weight (from 0.2 g to 10 kg), fragility (from jelly to aluminum profile), size scale (from 0.46 mm to 0.55 m), and shape (from poorly pinchable to poorly suckable). We further demonstrate its adaptability and robustness in handling irregular-shaped objects, and its proficiency in executing complex real-world manipulation tasks, underwater operations, and closed-loop grasping. Its enhanced grasping diversity is poised to accelerate diverse applications in daily life, industrial settings, and underwater scenarios.
Universal grasping — the ability to adapt to a wide range of objects and tasks without requiring customized adjustments — is essential for robotic grippers. A key to achieving this lies in designing grippers with flexibility and adaptability, allowing robots to handle unknown objects and complex environments as humans do. However, the vast diversity in object weight, fragility, size, and shape poses long-standing challenges to this goal.
Previous studies have primarily adopted two strategies to enhance grasping diversity in robotic grippers: multi-mechanism fusion and soft–rigid structural coupling. However, current robotic grippers often suffer from conflicts between different mechanisms or structural elements, preventing full utilization of their advantages.
Each grasping mechanism has its limitations. For instance, enveloping grippers struggle with flat objects, while suction-based grippers cannot handle porous items. Combining pinch and suction mechanisms — inspired by an elephant trunk — significantly improves adaptability.
Soft–rigid structural coupling mimics the human finger's internal bone structure and outer soft tissue (muscles and skin), offering both strength and compliance. Rigid grippers provide high output force and precision but lack adaptability, while soft grippers are highly adaptive but have limited load capacity.
The gripper features separate soft and rigid actuation systems, enabling four distinct operating modes through independent or combined control:
High-force grasping for heavy objects
Delicate handling of fragile items
Handling large or flat objects
Combined pinch + suction for stability
The gripper incorporates a Selective Activation Mechanism (SAM), enabling complete decoupling between rigid and soft actuators to harness their respective advantages. Additionally, a compliant adaptive module — composed of passive telescopic fingers and a retractable soft suction cup — allows seamless switching between pinch and suction modes without additional actuators or active control.
The soft structure allows gentle interaction with fragile items, while the rigid structure supports heavy, hard objects. The HMG demonstrates unprecedented versatility across multiple dimensions:
From 0.2g feather to 10kg dumbbell
From crispy chips to rigid aluminum
From 0.46mm tea leaves to 0.55m yoga balls
Flat cards, prickly cacti, porous towels
Comprehensive experimental validation demonstrates the HMG's superior performance across diverse object categories. The system achieves a 90% overall success rate while maintaining gentle handling for fragile objects and secure grasping for heavy items.
The HMG's unprecedented grasping diversity opens new possibilities for autonomous robotic systems in diverse environments, from household assistance to industrial automation and space exploration.
Handling diverse household objects from delicate glassware to heavy appliances
Flexible assembly lines capable of handling varied components without tool changes
Gentle patient assistance and precise medical instrument manipulation
Versatile manipulation in environments where tool diversity is constrained
This research introduces a groundbreaking Hybrid Multimodal Gripper that achieves unprecedented grasping diversity through innovative soft-rigid coupling and pinch-suction mechanisms. The HMG's ability to handle objects spanning five orders of magnitude in weight and three orders of magnitude in size represents a significant advancement toward truly universal robotic grasping. The successful integration of multiple mechanisms without performance conflicts opens new pathways for versatile robotic manipulation systems.
@article{zhao2025enhancing,
author = {Zhao, Yuwen and Zhu, Jiaqi and Zhang, Jie and Zhang, Siyuan and Shao, Maosen and Chai, Zhiping and Liu, Yimu and Wu, Jianing and Wu, Zhigang and Zhang, Jinxiu},
title = {Enhancing Grasping Diversity With a Pinch-Suction and Soft-Rigid Hybrid Multimodal Gripper},
journal = {IEEE Transactions on Robotics},
volume = {41},
pages = {3890--3907},
year = {2025},
}