Add omni drive robot to mobile_robot_kinematics

[Amronos]

…sing Omni Wheels

Updated mobile_robot_kinematics.rst as asked in #1535.

[christophfroehlich]

Thanks. I just found another thing: $$R$$ should be measured to the center of the wheel, right? compare to the wheeltrack of the DiffDrive sketch, maybe you can add black dimension lines (and leave the green ones only for velocity, angular rate).

[Amronos]

R should be measured to the center of the wheel, right?

Nope! It's from the center of the robot to the point where the wheel touches the robot as shown by the green arrow.

I have represented the velocities of the robot in blue and things related to measurements in green.

[christophfroehlich]

R should be measured to the center of the wheel, right?

Nope! It's from the center of the robot to the point where the wheel touches the robot as shown by the green arrow.

Nope, according to the literature it is the center of the wheel, not the innermost point. See this screenshot of the ModernRobotics book, which is linked on the page.

I have represented the velocities of the robot in blue and things related to measurements in green.

What about this style? It has similar style as the other sketches.

omni_wheel_omnidirectional_drive.zip

[Amronos]

Nope, according to the literature it is the center of the wheel, not the innermost point. See this screenshot of the ModernRobotics book, which is linked on the page.

Have a look at this screenshot from the same book, look at the symbol d (it is the radius). The screenshot that you shared just represents how a mecanum wheel works.

What about this style? It has similar style as the other sketches.

I am okay with it, though I liked mine a bit more. Please commit whatever you think would be the best and merge the PR, I won't be able to make any commits for a few days.