Lobster

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Lobster is a tool for solving the inverse-kinematics of 6-axis robot arms

Members: 88
Latest Activity: 15 hours ago

Lobster_IK1.ghx

Lobster_IK1.3dm

Lobster_IK.pdf

This is still a work-in-progress, with plenty of room for improvement.

I've been meaning to release this for some time - I was intending to clean it up some more and maybe compile it into a proper component first, but have been too busy with other activities, and rather than delay any longer have decided to share it in its current state.

It is a purely geometric solution, specific to this particular joint configuration, which allows kinematic decoupling, greatly simplifying things. Luckily most commercial 6-axis arms follow this configuration.

Bear in mind the angle value outputs are not yet calibrated - one would need to check the direction and start angles to make sure they corresponded with the standard format. Also, joint angle limits are not included here, but could be fairly easily added.

The example model here is a Kuka KR-150, but it is designed so that one can easily swap the input model with other robots with the same joint configuration (6-axis with a spherical wrist).

I do also have a similar definition for robots such as the ones from Universal Robots which do not have a spherical wrist, but still have certain simplifying properties allowing a closed form solution:

I'll post the setup for this one too soon.

Lobster is distributed under the WTFPL license ;)

Use at your own risk. I accept no responsibility if you break your robot!

enjoy !

Discussion Forum

videos

Some videos from early tests: http://vimeo.com/22196011 http://vimeo.com/22519535 …Continue

Started by Daniel Piker Jul 17, 2011.

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Comment by Khaled ElAshry on March 8, 2013 at 5:31pm: Hi Daniel , this looks great , I wanted to ask is the one for the universal robots available.

Comment by Freddy on November 27, 2012 at 8:46pm: Hello Greg,

Invitation accepted.

Comment by Gregory Epps on November 27, 2012 at 4:45am: Hi Freddy, we can build you a post - and integrate it into the simulation as well. I'll message you and we can discuss. Greg

Comment by Freddy on November 26, 2012 at 8:33pm: Hi Greg,

Apart from files Lobster IK1.3dm and Lobster IK1.ghx is there a gha file to place in the special folder ---> components folder in GH?.

I want to use lobster to lay bricks, what would the price for the post?

https://vimeo.com/22196011

cheers,

Freddy

Comment by Gregory Epps on November 26, 2012 at 3:46pm: Hi Freddy,
Lobster will just simulate the robot. You need to convert the end effector coordinates etc into code with a post processor. This is usually the bit you need to pay for, unless you can get an academic licence - or work out how to do it yourself.
Good luck... Greg, ROBOFOLD.

Comment by Freddy on November 26, 2012 at 1:13pm: Hi,

I tried a sample file in KukaPRC and output the SRC to a KRC1 Robot:

Kuka PRC with KRC1 from Freddy Chang on Vimeo.

How do I output SRC from Lobster?

thanks,

Comment by Yusuf Buyruk on November 24, 2012 at 8:47am: Some components like Orient, Rotate are old. I have replaced with the newer ones.

Here are the links of the files.

Again! Use at your own risk. I accept no responsibility if you break your robot! :)

Lobster_IK1.3dm

Lobster_IK1.ghx