Add gimbal gazebo plugin, applying in task1 to stabilize the camera.

[tongtybj]

• [jsk_mbzirc_tasks/urdf/gimbal] Add directory for gimbal urdf description
• [jsk_mbzirc_tasks/include/jsk_mbzirc_tasks/mbzirc_gazebo_gimbal_plugin.h, jsk_mbzirc_tasks/src/mbzirc_gazebo_gimbal_plugin.cpp]Add code about gimbal gazebo plugin, including the control about horizontal stabilization.
• [jsk_mbzirc_tasks/urdf/quadrotor_with_hokyo30lx_and_downward_cam.urdf.xacro] Add gimbal module for camera stabilization.

[tongtybj]

This PR is about the gimbal plugin in gazebo, which is separated from commit in #65, and was also discussed in #66

In #66 :

This is nice comparison, please describe the velocity and tilting angle of this experiment, and also check behavior of your drone with same velocity.

I redid the same experiment as shown in the gif

The max tilting angle is about 30degree(0.53rad) and velocity is about 4m/s(14.4km/h).

[tongtybj]

Is there any review or comment about this PR?

[k-okada]

#85 (comment)

[tongtybj]

both are necessary.

• When we give a big acceleration command to a uav for horizontal movement , it will tilt with a large angle like 30 degree. With this tilt angle, we will lost the view of the arena even we have fisheye FOV. The gif in add gimbal moudle for stabilizing sensors such as camera #66 "Camera(FOV=160) without gimbal while moving rapidly" is a good example, which indicates that we will lost the truck sometime.
• On the other hand, fisheye is also necessary, because we need very big FOV in the finally landing porces, othewise we can not capture the whole feature of heliport(I mean the "X"). Please check video in https://drive.google.com/open?id=0BwphddqBjVJ_RnYzSjh5WHJKMWc.

[k-okada]

ok, so you now have 160 degree of camera and the biggest tilting angle is
30 degree, so you need 160 + 30 + 30 = 220 degree angles,
from my little knowledge, we had 210 degree camera at lab
http://www.universekk.com/product/fisheye-rends.html
http://xs-optical.manufacturer.globalsources.com/si/6008849928141/pdtl/Megapixel-CCTV/1128257360/Fisheye-Lens.htm

And google knows more wider lens.
http://www.entapano.com/jp/l/

◉ Kei Okada

On Tue, Jun 14, 2016 at 6:03 AM, 趙 漠居 [email protected] wrote:

both are necessary.

When we give a big acceleration command to a uav for horizontal
movement , it will tilt with a large angle like 30 degree. With this tilt
angle, we will lost the view of the arena even we have fisheye FOV. The gif
in #66 #66
"Camera(FOV=160) without gimbal while moving rapidly" is a good example,
which indicates that we will lost the truck sometime.

On the other hand, fisheye is also necessary, because we need very big
FOV in the finally landing porces, othewise we can not capture the whole
feature of heliport(I mean the "X"). Please check video in
https://drive.google.com/open?id=0BwphddqBjVJ_RnYzSjh5WHJKMWc.

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[tongtybj]

@k-okada
Wonderful knowledge I never know before...
So I will do experiment about gimbal + fisheye vs superfisheye.

And, when we use superfisheye like 220 degree, should be the resolution of camera big? like 5MP?

[k-okada]

And, when we use superfisheye like 220 degree, should be the resolution
of camera big? like 5MP?

this is exactly what we want to test with in simulator.

◉ Kei Okada

On Tue, Jun 14, 2016 at 10:14 AM, 趙 漠居 [email protected] wrote:

@k-okada https://github.com/k-okada
Wonderful knowledge I never know before...
So I will do experiment about gimbal + fisheye vs superfisheye.

And, when we use superfisheye like 220 degree, should be the resolution of
camera big? like 5MP?

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[tongtybj]

@iKrishneel

Could you please change the FOV to 220 degree, and see the performance of your visual detection about the heliport.

[cretaceous-creature]

seems we cant change the hfov above 180, error will happen..
[image: 埋め込み画像 1]

2016-06-14 10:28 GMT+09:00 趙 漠居 [email protected]:

@iKrishneel https://github.com/iKrishneel

Could you please change the FOV to 220 degree, and see the performance of
your visual detection about the heliport.

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[tongtybj]

Yeah, I know that bug...
And I can not see your image...

[cretaceous-creature]

Exception [Camera.cc:221] Camera horizontal field of view invalid

2016-06-14 11:35 GMT+09:00 趙 漠居 [email protected]:

Yeah, I know that bug...
And I can not see your image...

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[tongtybj]

We can make a patch and send PR to gazebo_plugins

[iKrishneel]

@tongtybj perhaps the detection should work but incase if it does not work well, we can rectify the frames I think.