unable to set min_in_place_vel_theta more than 3.14

edit

I have 50 kg differential drive robot which needs a considerable amount of torque to start turning in place, usually anglular.z of at least 10 rad/s. Using rqt_reconfigure I'm trying to set min_in_place_vel_theta incrementally and it all works up to a value of 3.14 which is exactly echoed in cmd_vel. But when the min_in_place_vel_theta become larger than 3.14, cmd_vel changes sign and decrements. Looks like some sort of harmonic function when incremented further with breakpoints at multiples of 3.14.

C:\fakepath\move_base.gif

edit: Since attachments does not work, here is the table:

min_in_place_vel_thera cmd_vel
1.6 1.6
1.8 1.8
2.0 2
2.2 2.2
2.4 2.4
2.6 2.6
2.8 2.8
3.0 3
3.2 -3.08
3.4 -2.88
3.6 -2.68
3.8 -2.48
4.0 -2.28
4.2 -2.08
4.4 -1.88
4.6 -1.68
4.8 -1.48
5.0 -1.28
5.2 -1.08
5.4 -0.88
5.6 -0.68
5.8 -0.48
6.0 -0.28
6.2 -0.08
6.4 0.11
6.6 0.31
6.8 0.51
7.0 0.71
7.2 0.91
7.4 1.11
7.6 1.31
7.8 1.51
8.0 1.71
8.2 1.91
8.4 2.11
8.6 2.31
8.8 2.51
9.0 2.71
9.2 2.91
9.4 3.11
9.6 -2.96
9.8 -2.76
10.0    -2.56
10.2    -2.36
10.4    -2.16
10.6    -1.96
10.8    -1.76
11.0    -1.56
11.2    -1.36
11.4    -1.16
11.6    -0.96
11.8    -0.76
12.0    -0.56
12.2    -0.36