# Designing a Mechanical Tool for Robots with 2-Finger Parallel Grippers

## TL;DR

This paper presents a mechanical tool for 2-finger parallel gripper robots that extends gripping capabilities without extra actuators, using a symmetric parallelogram structure with springs for versatile task performance.

## Contribution

The work introduces a novel kinematic structure for a mechanical tool that enhances robotic gripper functions without additional actuators or tool exchangers.

## Key findings

- The mechanical tool effectively transmits gripper motion to open and close the tool.
- The design allows for various tooltips to perform different tasks.
- Robots can automatically locate, grasp, and use the tool for diverse operations.

## Abstract

This work designs a mechanical tool for robots with 2-finger parallel grippers, which extends the function of the robotic gripper without additional requirements on tool exchangers or other actuators. The fundamental kinematic structure of the mechanical tool is two symmetric parallelograms which transmit the motion of the robotic gripper to the mechanical tool. Four torsion springs are attached to the four inner joints of the two parallelograms to open the tool as the robotic gripper releases. The forces and transmission are analyzed in detail to make sure the tool reacts well with respect to the gripping forces and the spring stiffness. Also, based on the kinematic structure, variety tooltips were designed for the mechanical tool to perform various tasks. The kinematic structure can be a platform to apply various skillful gripper designs. The designed tool could be treated as a normal object and be picked up and used by automatically planned grasps. A robot may locate the tool through the AR markers attached to the tool body, grasp the tool by selecting an automatically planned grasp, and move the tool from any arbitrary pose to a specific pose to grip objects. The robot may also determine the optimal grasps and usage according to the requirements of given tasks.