Design of a Hydraulic-Driven Adaptive Gripper with a Novel Actuation Mechanism
Yonghwan Jeong, Jungyeong Kim, SangChul Han, Sungwoon Yoon, Sungho Lee, Sangshin Park, Jin Tak Kim, Jinhyeon Kim, Jungsan Cho
AI summary
Problem
Hydraulic grippers for heavy industrial and field robotics are typically bulky due to complex linear-to-rotational motion conversion and lack precise force control in harsh environments where external sensors are impractical.
Approach
The design integrates a fixed horizontal cylinder with an offset slider-crank mechanism to minimize palm length, alongside a novel double-acting bi-piston cylinder that drives both fingers with a single actuator and uses torsion springs for passive synchronization.
Key results
- Compact offset slider-crank mechanism reduces structural volume and palm length
- Single double-acting bi-piston cylinder enables synchronized two-finger actuation with fewer hydraulic components
- Passive torsion spring synchronization compensates for piston desynchronization without external sensors
- Prototype successfully lifts an 18 kg tire and delicately grasps fragile items like eggs and paper cups
Why it matters
Provides a reliable, compact, and high-force grasping solution for field robotics and heavy industrial applications where sensor-based control is impractical.
Abstract
This letter presents a novel hydraulic-driven two- finger robotic gripper designed to handle objects of various shapes andsizes.Tomeetthedemandsoffieldroboticsandheavyindustrial environments, a self-adaptive finger mechanism was integrated with hydraulic actuation. However, this integration leads to in- creasedstructuralvolume, ashydraulicsproducelinearmotionand require additional hydraulics components. Additionally, precise force control becomes challenging, as harsh environments limit the use of other sensing devices for fine control. These issues are addressed by employing an offset slider-crank mechanism, which efficiently converts linear motion into rotational motion. Addition- ally, a newly designed double-acting bi-piston cylinder allows both fingers to operate using a single cylinder, reducing the number of hydraulic components. To enable pressure-based force control, kinematic and static analyses of the mechanism were conducted. A prototype was developed and experimentally validated for its grasping performance and analysis. It demonstrated high perfor- mance in lifting heavy objects, such as an 18 kg tire, and delicately handling fragile items like eggs and paper cups.