The AR Gripper is an open hardware parallel robot gripper designed for handling everyday items such as bottles and cups.
The project is now hosted on Printables. https://www.printables.com/model/657807-ar-gripper-open-hardware-adaptive-electric-paralle
Rendering of the AR Gripper
The AR Gripper in real life
I designed this gripper because I couldn't find any robot grippers that fulfilled my requirements of building my bartender robot "Roberto the Robot" which are the same time cost-effective.
Roberto with the Robotiq Hand-E end of 2019
Roberto with the Robotiq Hand-E end of 2019
I first tried the Robotiq Hand-E, because it was available to me. It is an adaptive electric parallel gripper with a stroke of 50mm. Unfortunately, the items I liked to handle had a diameter of up to 90mm (big coke bottle) and the price is quite high (>3000$). However, I liked the simplicity and modular design of the gripper. For the first version of Robert, I designed custom gripper fingers that made it possible to grip tools and bottles using a special counterpart. Another huge disadvantage of the Hand-E is its weight of 1kg, which is okay for the Borunte robot I used, but can be a challenge for smaller robots.
Because I wanted to handle bottles and other tools without prior modification I started to look for alternative grippers. My requirements were:
Most of the gripper products I found did not satisfy the cost requirements or were just too small. I also found a couple of open hardware designs, such as for example the open hand project, but they all looked discarded.
I then found a the SAKE Robotics EZGripper an under actuated electric gripper design, which satisfied all of my requirements. I used this gripper to improve Roberto the bartender and the gripper mostly worked as expected. However, I needed to make some adaptions to the gripper pads, to increase the friction between bottle and gripper.
Roberto with the EZGripper mid 2020
Roberto with the EZGripper mid 2020