Xtion frames

[pattacini]

As of now we have one frame attached to the mechanical center of the Xtion.

For control purpose, we would need to:

1. Move the frame above called depth to the actual center of the depth sensor.
2. Introduce a further frame we can call depth_rgb to be attached to the center of the Xtion rgb sensor.

@fiorisi is going to deal with this request (not urgent) next week.

Note

Other frames already available are:

• left
• right
• cyclopic, attached to the middle of left and right
• gaze, attached to the middle of the screen

cc @randaz81 @barbalberto @vtikha

[pattacini]

@fiorisi please also consider that Marcello is willing to mount asap the new mechanical support of the Xtion, which will entail to move the two RGB cameras slightly apart (~ 2 mm).

Therefore, could you take this into account and provide new DH parameters for the cameras' frames as well?

[fiorisi]

Yes, no problem.

[fiorisi]

regarding the Xtion, do you want 2 different tags (one for the depth sensor and one for the rgb sensor) or do you have a solution to embed the camera inside of the depth (or vice-versa)?

[pattacini]

I'd go for depth and depth_rgb, as reported above.

[barbalberto]

The most flexible solution appears to have 2 different sensors in the urdf/sdf, a rgb and a depth camera. In this case, playing with config file, we could have the realistic robot configuration (rgb and depth camera NOT colocated) or the ideal configuration where the 2 sensor are colocated. (or both)

[pattacini]

With @fiorisi we agreed to keep in the model also the fake frame attached to the center of Xtion device for control purpose. It will be termed depth_center (actually it's not cyclopic)

[fiorisi]

Testing the following frames: depth_center, depth and depth_rgb. The test are performed by computing the transform between the base_link and the frame to be tested using our forward kinematics library and our CAD model. The position of the joints that belong to the kinematic chain (between base_link and the frame to be tested) is defined by the vector q. The CAD model is updated accordingly.

frame=depth_center

q=( 0.00000 0.00000 0.00000 0.00000 0.00000 0.00000)

IPOPT H=-0.00000 0.00000 1.00000 0.02156 -1.00000 0.00000 -0.00000 0.00000 -0.00000 -1.00000 0.00000 1.07240 0.00000 0.00000 0.00000 1.00000

CREO

q=( 0.01500 0.00000 0.00000 20.00000 15.00000 0.00000)

IPOPT H= 0.33993 -0.34839 0.87354 0.13368 -0.93969 -0.08852 0.33037 0.00941 -0.03777 -0.93316 -0.35747 1.04557 0.00000 0.00000 0.00000 1.00000

CREO

---

frame=depth

q=( 0.00000 0.00000 0.00000 0.00000 0.00000 0.00000)

IPOPT H=-0.00000 0.00000 1.00000 0.02156 -1.00000 0.00000 -0.00000 0.04449 -0.00000 -1.00000 0.00000 1.07240 0.00000 0.00000 0.00000 1.00000

CREO

---

frame=depth_rgb

q=( 0.00000 0.00000 0.00000 0.00000 0.00000 0.00000)

IPOPT H=-0.00000 0.00000 1.00000 0.02156 -1.00000 0.00000 -0.00000 0.01849 -0.00000 -1.00000 0.00000 1.07240 0.00000 0.00000 0.00000 1.00000

CREO

[fiorisi]

Testing the following frames: left, right, cyclopic and gaze.

frame=left

q=( 0.00000 0.00000 0.00000 0.00000 0.00000 0.00000)

IPOPT H=-0.00000 0.00000 1.00000 0.01385 -1.00000 0.00000 -0.00000 0.03351 -0.00000 -1.00000 0.00000 0.96090 0.00000 0.00000 0.00000 1.00000

CREO

---

frame=right

q=( 0.00000 0.00000 0.00000 0.00000 0.00000 0.00000)

IPOPT H=-0.00000 0.00000 1.00000 0.01385 -1.00000 0.00000 -0.00000 -0.03351 -0.00000 -1.00000 0.00000 0.96090 0.00000 0.00000 0.00000 1.00000

CREO

---

frame=cyclopic

q=( 0.00000 0.00000 0.00000 0.00000 0.00000 0.00000)

IPOPT H=-0.00000 0.00000 1.00000 0.01385 -1.00000 0.00000 -0.00000 0.00000 -0.00000 -1.00000 0.00000 0.96090 0.00000 0.00000 0.00000 1.00000

CREO

---

frame=gaze

q=( 0.00000 0.00000 0.00000 0.00000 0.00000 0.00000)

IPOPT H=-0.00000 0.00000 1.00000 0.01116 -1.00000 0.00000 -0.00000 0.00000 -0.00000 -1.00000 0.00000 1.01450 0.00000 0.00000 0.00000 1.00000

CREO

[pattacini]

Thank you @fiorisi !