Difficulty using ikfast generator, "need 6 joints error" with Kuka Youbot

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Hi,

I'm new to ikfast and I'm trying to understand it. I've been following the documentation here: http://moveit.ros.org/wiki/Kinematics/IKFast

I'm using a Kuka youbot urdf file which I converted to a .dae file.

When I do an --info links on my robot, I get the following:

name index parents

base_footprint 0
base_link 1 base_footprint
arm_link_0 2 base_link
arm_link_1 3 arm_link_0
arm_link_2 4 arm_link_1
arm_link_3 5 arm_link_2
arm_link_4 6 arm_link_3
arm_link_5 7 arm_link_4
gripper_palm_link 8 arm_link_5
gripper_finger_link_l 9 gripper_palm_link gripper_finger_link_r 10 gripper_palm_link base_laser_front_link 11 base_link
caster_link_bl 12 base_link
wheel_link_bl 13 caster_link_bl
caster_link_br 14 base_link
wheel_link_br 15 caster_link_br
caster_link_fl 16 base_link
wheel_link_fl 17 caster_link_fl
caster_link_fr 18 base_link
wheel_link_fr 19 caster_link_fr
plate_link 20 base_link

And when I look up the joints, I get: name index parents
andy@andy-VirtualBox:~/catkin_ws/collada_files2$ openrave0.8-robot.py youbot.dae --info joints

name joint_index dof_index parent_link child_link mimic

arm_joint_1 0 0 arm_link_0 arm_link_1
arm_joint_2 1 1 arm_link_1 arm_link_2
arm_joint_3 2 2 arm_link_2 arm_link_3
arm_joint_4 3 3 arm_link_3 arm_link_4
arm_joint_5 4 4 arm_link_4 arm_link_5
gripper_finger_joint_l 5 5 gripper_palm_link gripper_finger_link_l
gripper_finger_joint_r 6 6 gripper_palm_link gripper_finger_link_r
base_footprint_joint -1 -1 base_footprint base_link
arm_joint_0 -1 -1 base_link arm_link_0
gripper_palm_joint -1 -1 arm_link_5 gripper_palm_link
base_laser_front_hokuyo_urg04_laser_joint -1 -1 base_link base_laser_front_link
caster_joint_bl -1 -1 base_link caster_link_bl
wheel_joint_bl -1 -1 caster_link_bl wheel_link_bl
caster_joint_br -1 -1 base_link caster_link_br
wheel_joint_br -1 -1 caster_link_br wheel_link_br
caster_joint_fl -1 -1 base_link caster_link_fl
wheel_joint_fl -1 -1 caster_link_fl wheel_link_fl
caster_joint_fr -1 -1 base_link caster_link_fr
wheel_joint_fr -1 -1 caster_link_fr wheel_link_fr
plate_joint -1 -1 base_link

Now, I apologize for my newness to the ikfast package, so I'm trying to understand exactly what this means. I assume a -1 means no dof is provided by the joint (so, it's fixed or something), and that each number 0 through 6 provides the cumulative dof at that joint.

Therefore, my understanding is that the correct 6DOF command to generate the IKSolver would be:

python /usr/lib/python2.7/dist-packages/openravepy/_openravepy_0_8/ikfast.py --robot=youbot.dae --iktype=transform6d --baselink=3 --eelink=10 --savefile=output_ikfast61.cpp

But I get the following error:

/usr/lib/python2.7/dist-packages/openravepy/_openravepy_0_8/ikfast.py:1122: RuntimeWarning: invalid value encountered in divide axisangle /= angle INFO: moved translation [0, 0, 13/100] to right end INFO: moved translation [0, 0, 19/1000] to left end INFO: moved translation on intersecting axis [0, 0, 0] to left INFO: [[1, 0, 0, 3/125],[0, 1, 0, 0],[0, 0, 1, 23/200]] INFO: [[cos(j0), -sin(j0), 0, 0],[sin(j0), cos(j0), 0, 0],[0, 0, 1, 0]] INFO: [[1, 0, 0, 33/1000],[0, 0, -1, 0],[0, 1, 0, 0]] INFO: [[cos(j1), -sin(j1), 0, 0],[sin(j1), cos(j1), 0, 0],[0, 0, 1, 0]] INFO: [[1, 0, 0, 0],[0, -1, 0, 31/200],[0, 0, -1, 0]] INFO: [[cos(j2), -sin(j2), 0, 0],[sin(j2), cos(j2), 0, 0],[0, 0, 1, 0]] INFO: [[1, 0, 0, 0],[0, -1, 0, -27/200],[0, 0, -1, 0 ... (more)