Re: [ros-users] replicating pr2_arm_kinematics for 6-DOF arm

Thanks, Morgan. I'm trying this out right now.

On Sat, Jul 17, 2010 at 11:37 AM, Morgan Quigley
<mquigley@cs.stanford.edu> wrote:
> Hi Dave,
>
> The Orocos KDL library is great. I just switched to it last week; my
> code is pretty ugly, but it's using the KDL::ChainIkSolverPos_NR_JL
> class, which has joint limits:
>
> http://stanford-ros-pkg.googlecode.com/svn/trunk/openarms/control/goto_cart.cpp
>
> The ik_tool() function is what you're after. You set the joint limits
> when you construct the ChainIkSolverPos_NR_JL object; search for
> "ik_solver_pos" in that .cpp file to see the exact syntax.
>
> (sorry about all the commented code... it's a work in progress)
>
> HTH,
> Morgan
>
>
> On Sat, Jul 17, 2010 at 10:43 AM, David Feil-Seifer
> <david.feilseifer@gmail.com> wrote:
>> I am trying to replicate the IK-functionality of pr2_arm_navigation
>> for our humanoid robot, Bandit. I have attached a xacro file for it's
>> arm. I have it rendering correctly, and am able to have it mimic the
>> movements of a real Bandit with joint_states_publisher and a
>> /joint_states message. I seem to have correctly ported
>> pr2_arm_ik_solver and pr2_arm_kinematics by simply changing all 7's to
>> 6's and changing the names of the root and tip links
>> (bandit_torso_link and left/right_hand_link). However, I'm having
>> trouble with pr2_arm_ik.cpp. Clearly, the math here was meant for a
>> 7-DOF arm, and I don't really know what algorithm is being used here,
>> so I'm having trouble translating that to a 6-DOF arm. I have figured
>> out that in the init function, that I needed to change the
>> link_offsets for the shoulder_upperarm_offset, elbow_wrist offset, and
>> upperarm_elbow_offset values. Those are now correct. I am just having
>> trouble making computeIKShoulderPan and computeIKShoulderRoll to a 6
>> joint arm. Can anyone give me some guidance on how to proceed?
>>
>> I did look at the KDL examples on their website, but they were pretty
>> vague about creating an IK solver with joint limits.
>>
>> Thanks for your help.
>> -Dave
>>
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