Advice for tweening compound hinged motion

[shifty 0 Likes (Newbie)]

Here's the situation:

 

I have a scene where I have articulated robot arms moving around. I'm using TimelineMax to manage all the animations using nested timelines, which eventually end in individual TweenMax instances to handle each individual bit of motion. So, there's a timeline for each full sequence, each step in the sequence is a nested timeline, and there's potentially multiple tweens in each step (multiple parts moving, etc.) The robot arms were modeled in Blender/Maya and imported using the DAE class in Papervision3D.

 

Essentially, what I need to do is make the arms move using local rotations (only local rotations, since the robot parts must stay together physically) on each individual part, while maintaining a straight path of motion for the end piece. So, envision a robot arm composed of a base, a lower arm, and an upper arm, connected together in a chain. I need to rotate those arms at their pivots so that the end of the upper arm stays in a linear path.

 

I'm trying use eases to control the speed of motion on each rotation, so that when each part is rotating simultaneously, the eases work together in such a way that the endpoint stays linear.

 

I'm not having the best of luck. Has anyone dealt with this? How is this sort of thing handled typically? Trying to modify rotation angles and eases is very time consuming, and really just a lot of guessing, because the rotations are chained together and downstream rotations are very difficult to envision.