Upgrade to Openarm Cell but with modifications

[SKA1122]

Hello
I am planning to buy openarm 2 but my requirement is 1.5 meters z axis movement but open arm cell provides 300mm of z axis movement. Is it possible to buy it and modify it to 1.5 meters z axis?

[kou]

Thanks for your interest in OpenArm 2!

OpenArm Cell is designed as a standardized benchmark environment: the frame, Z-axis, lighting, cameras and calibration procedure are all fixed so that results from different Cells can be compared directly. Because of this, we don't offer customized variants of the Cell (e.g., a different Z-axis stroke). Also, the Cell frame is about 1.9 m tall, so a 1.5 m Z-axis stroke wouldn't physically fit inside it.

If you need 1.5 m of vertical travel, we'd recommend purchasing OpenArm 2 itself and mounting it on a lift or gantry that fits your requirements. The Cell's CAD data and BOM are publicly available, so feel free to use them as a reference for your own setup. Just note that a modified setup would no longer be a standard OpenArm Cell, and benchmark results wouldn't be directly comparable with other Cells.

Could you share a bit more about your use case? We may be able to give more specific advice.

[SKA1122]

Thank you for the reply. I will be using it for my research project using VLMs inside a closed room. So the robot has to complete multiple tasks. for example, the robot might need to pick up a box and place it on a height of 1.5m shelf for which I will need that vertical lift. The vertical lifts in the market are quite expensive, but my project budget is not that high. So can you suggest me some easier way, if i could design it myself and get it manufactured will it work?

[kou]

Designing and building your own lift is one possible option. The OpenArm 2.0 base is built on MISUMI aluminum frames with M6 taps, and the Cell's CAD data is public, so you could use them as a reference. However, please note that we can't provide support for custom lifts or modified setups, and building and operating one is at your own risk.

The OpenArm hardware designs, including OpenArm Cell, are licensed under CERN-OHL-S-2.0: https://github.com/enactic/openarm_hardware/blob/main/LICENSE.txt
You're free to use and modify them, but if you distribute a modified design or hardware based on it, you need to make the modified design sources available under the same license.

It may also be worth checking whether you really need 1.5 m of travel. OpenArm 2.0 is human-scale (roughly matching a person 160–165 cm tall), so the arm itself has a fair amount of vertical reach. Depending on your tasks, a higher mounting position or a shorter stroke might be enough.

If you do go the custom route, please keep in mind the arm's weight and moment load, position holding on power loss, and the payload limits (4.1 kg nominal / 6.0 kg peak, including the end-effector). Please also read our Safety Guide: https://docs.openarm.dev/overview/safety-guide

We'd also recommend asking in our Discord community. Other users may have built similar setups and can share practical tips: https://discord.gg/FsZaZ4z3We

[SKA1122]

Thanks a lot for your detailed reply. appreciate it. I will be buying it really soon.

[BotshareAI]

If longer vertical travel is the main need, one option is a separate lift column instead of the Cell. Our open model shows how we did that for OpenArm 2.0: a prismatic lift_joint with configurable column geometry and both arms rooted on the carriage: https://github.com/openAMRobot/openamr-upperbody-sw/blob/main/ros2/src/openamrobot_upperbody_description/config/upperbody_configuration.yaml. Our column strokes 350 mm, so 1.5 m needs a different column. Simulation and mock hardware only so far.