# Set limb position of a Baxter Robot using 3D cartesian Data

I want to ask if it is possible to set the arm position of a Baxter robot by stating the 3D Cartesian coordinate position of each joint instead of using joint angle. If it is possible to do this or if you have any ideas they are all welcome.

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What do you want to achieve? Giving 3d positions for all joints adds a lot of redundancy.

( 2017-04-06 05:28:51 -0500 )edit

@NEngelhard I want the arms of the Baxter robot to mimic the movements of a human arm. I have the 3D Cartesian coordinate data of the joints in the human arm so I want to suse those coordinates for the Baxter.

( 2017-04-06 05:35:06 -0500 )edit

But e.g. the distance between the joints is fixed, so you have to do some approximations.

( 2017-04-06 05:42:25 -0500 )edit

@NEngelhard Yes I know the length of the limbs are fixed, so do you know how to set the limbs using the 3D Cartesian Coordinate data?

( 2017-04-06 05:49:29 -0500 )edit

I think @NEngelhard meant that because the lengths between joints are fixed (and there are joint limits), for an arbitrary set of desired Cartesian joint positions from human motion data, there is a very low probability that Baxter can actually be at those positions.

( 2017-04-06 07:39:42 -0500 )edit

The fixed lengths act as constraints on which sets of Cartesian joint positions are even possible. You should likely be solving this problem as an optimization problem. E.g. minimize the Euclidean error between the desired Cartesian positions and the actual positions by choosing all joint angles.

( 2017-04-06 07:41:52 -0500 )edit

Once you have the angles, you can use standard joint interfaces to move the arm.

( 2017-04-06 07:42:24 -0500 )edit