Hybrid Rigid-Soft Robotic Gripper with Shape Adaptation, Uniform Force Distribution, and Self-Locking Capabilities
Xi Chen,,, Yun Wang,,, Lichao Yang,, Haitao Li, Ya Xiong,∗
AI summary
Problem
Conventional robotic grippers struggle to simultaneously achieve compliant adaptive grasping, uniform force distribution, and high load capacity without excessive energy consumption, particularly for fragile agricultural products.
Approach
The design combines low-cost membrane-based pneumatic actuators with a dual ratchet-pawl mechanism that passively locks joints to maintain shape adaptation and even force distribution without continuous power.
Key results
- Maximum load capacity of 4200 g, far exceeding conventional soft grippers
- Uniform force distribution with a 1.75–35.29% difference ratio across varying object sizes
- 50.05% reduction in energy consumption to 42.6 J per grasp cycle via self-locking
- Low-cost, easily fabricated architecture using additive manufacturing and commercial membranes
Why it matters
Provides a robust, energy-efficient, and cost-effective solution for scalable agricultural harvesting and manipulation of fragile, irregular objects.
Abstract
Conventional robotic grippers face a significant challenge in agricultural automation: the trade-off between compliant, adaptive grasping, pressure balancing among all joints, and high load capacity, often at the cost of high energy consumption. This paper presents a novel hybrid rigid-soft gripper that integrated low-cost, membrane-based pneumatic actuators with 3D-printed dual ratchet-pawl mechanisms to simultaneously achieve shape adaptation, uniform force distri- bution, and energy-free self-locking. The dual-ratchet structure assembled in an offset configuration significantly increased the angular resolution of the joint locking mechanism. Key experimental results demonstrated the gripper’s superior per- formance: a remarkable maximum load capacity of 4200 g, far exceeding that of conventional soft grippers (45–210 g); more uniform force distribution across object sizes (1.75–35.29% difference ratio) compared to a rigid gripper (56.77–66.44%), with peak contact forces remaining below surface damage thresholds; and a 50.05% reduction in total energy consumption to 42.6 J per grasp cycle, achieved by eliminating the need for continuous pneumatic pressure through the self-locking mechanism, compared to 85.28 J for a conventional soft grip- per. The combination of additive manufacturing for ratchets and commercially available materials for pneumatic chambers ensured a low-cost and easily fabricated design. These findings validated that the proposed gripper successfully bridged the gap between soft compliance and rigid reliability, offering a robust and efficient solution for scalable agricultural harvesting and manipulation tasks.