Design of a Hydraulic-Driven Adaptive Gripper With a Novel Actuation Mechanism

This letter presents a novel hydraulic-driven two-finger robotic gripper designed to handle objects of various shapes and sizes. To meet the demands of field robotics and heavy industrial environments, a self-adaptive finger mechanism was integrated with hydraulic actuation. However, this integration leads to increased structural volume, as hydraulics produce linear motion and 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. Additionally, 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 performance in lifting heavy objects, such as an 18 kg tire, and delicately handling fragile items like eggs and paper cups.