Coarse Sun Sensor `body` initializer

[ericstoneking]

Coarse Sun Sensor `body` initializer

[ericstoneking]

Hi Thatcher,

The Body number is the body that the CSS is mounted on. I've only had occasion to place CSSs or thrusters on appendage bodies. The comment on the CSS Axis line should at least be "! Body, Axis expressed in Body frame". I will take your suggestion and put the Body Index on its own line (for CSSs and thrusters). Don't bother with a PR.

Regards,
-Eric (he/him)

[ThatcherC]

Sounds good! Thanks for clearing that up. One other thing - does Body as referenced in the CSS definition refer to the same indexing as the Flex Node Index in other SC component definitions? I always have Flex Node Index set to 0 for wheels and torquers, like this:

*************************** Wheel Parameters ***************************
4                             ! Number of wheels
=============================  Wheel X - CubeWheel Large ================================
0.0                           ! Initial Momentum, N-m-sec
1.0   0.0   0.0               ! Wheel Axis Components, [X, Y, Z]
0.0023   0.03                   ! Max Torque (N-m), Momentum (N-m-sec)
0.0000477                         ! Wheel Rotor Inertia, kg-m^2
0.0                          ! Static Imbalance, g-cm
0.0                          ! Dynamic Imbalance, g-cm^2
0                             ! Flex Node Index

**************************** MTB Parameters ****************************
3                             ! Number of MTBs
==============================  MTB 0  =================================
1.27                           ! Saturation (A-m^2)
1.0   0.0   0.0               ! MTB Axis Components, [X, Y, Z]
0                             ! Flex Node Index

which I always took to mean that these components are mounted on/in Body 0. Are Bodies and Flex Nodes equivalent? It could be advantageous to use the same names for them in the example files if so. And if they're not referring to the same thing, I'd love to learn the difference between them! I haven't found a distinction yet in Docs/42 Joints.pdf or Docs/42 Overview.pdf but I'm doing some more reading this morning on it.

Thanks!
Thatcher

[ericstoneking]

Hi Thatcher,

Flex Nodes are a whole different thing. See Docs/Kane_NBody_Flex.pdf slide 9. The "few points" mentioned there are flex nodes. The flex node indices in the SC file refer to the "Analysis Node Locations" defined in the (eg.) InOut/Flex_Simple.txt.

Regards,
-Eric (he/him)

[ericstoneking]

See today's commit.