Passive Adaptive Object Prehension, Retention, and Release with a Mechanically Intelligent Gripper
Ming Chun CHAN, Jiayun LI , Ziyao WU, Nan WANG, and Rob B.N. SCHARFF∗
AI summary
Problem
Adaptive robotic grippers typically rely on complex actuators and sensors, making them costly, energy-inefficient, and vulnerable in harsh environments, while existing passive designs lack true shape adaptation or require ground contact for release.
Approach
The gripper uses a contact-triggered compliant linkage with Fin Ray fingers to passively adapt to object shapes, a linear ratchet to lock the grip during transport, and an asymmetric gravity-based mechanism to release objects when tilted.
Key results
- Design and kinematic modeling of a compliant linkage with Fin Ray fingers for adaptive grasping
- Development of a linear ratchet mechanism enabling secure, zero-energy object retention
- Implementation of a gravity-driven asymmetric release mechanism for contactless object dropping
- Experimental validation of grasping kinematics, locking forces, friction coefficients, and release thresholds across varying payloads
Why it matters
Provides a robust, low-cost, and energy-free manipulation solution ideal for extreme or inaccessible environments like underwater, aerial, or contaminated settings.
Abstract
This article presents a mechanically intelligent grip- per that is capable of passive and adaptive object prehension, passive object retention, and passive object release. Passive adaptive prehension is achieved through a compliant linkage with two Fin Ray fingers that enclose an object when the gripper is pushed onto it. The object is held firmly in place during transport by a linear ratchet mechanism that locks the compliant mechanism in place. An asymmetric ratchet release mechanism releases the object using gravitational force when the gripper is maneuvered in its release-orientation. The absence of actuators, electronics, and a tether or embedded power source make the presented adaptive gripper a promising technology for challenging environments where low energy consumption and robustness to dirt and water are critical.