Problem Statement / Background

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Problem Statement

"Develop a robotic linkage for the Robotiq end effector which will minimize grasper volume in the open configuration while maintaining grasp capabilities of the original design."

 Concept photo of the desired modification to the Robotiq three-finger gripper (3 finger gripper, 2016)

In support of the UT Nuclear and Applied Robotics Lab, we have been tasked with modifying the current robotic grasping mechanism such that the redesign will minimize the open configuration grasper volume. The end product should be able to grasp objects ≤ 6” in diameter, weighing ≤ 2 kg. When open, the fingers should retract or curl in such a way to reduce the effective volume of the end effector, thereby increasing movement efficiency, and reducing collision potential during motion.

Background

The original Robotiq gripper is a three finger gripper end effector. Unlike traditional robotic grippers which are constrained to one degree of freedom, this adaptive gripper has multiple degrees of freedom, which enable the gripper to pinch-grip objects with small diameters (<4” ) and encompass-grip around objects with diameters >= 4” in diameter/width.The table below indicates some of the gripper design specifications.

Ours was a proof of concept project, with an objective of designing a retrofit mechanism for one finger which will enabled that finger to retract its entire length below the height of the palm while maintaining all the original grip capabilities. For simplicity and time, we chose to ignore repeatability and grip strength requirements, with the expectation that these topics should be addressed in any further work.

>> First Prototype: 7-Bar Retractor