Planetary Gear Train in MDX/MDO

Thanks for your suggestion. Unfortunately, this will not solve my issue. I have attached a representative model set for review. The challenge is to have a proper planetary gear train that will allow control over any of the main elements - sun, carrier and ring. For example, in a typical automotive planetary transmission, we might "gang" 2 or more simple planets together to be able to select a number of different output speeds. This is done by selecting the sun, ring or carrier to be held while simultaneously locking any two of these members together to change how the torque is passed through one planetary set and on to the next (those are your "clutches" and "bands" in your transmission). The model I have shared allows for this with basic pin joints all going to a "ground". In my actual system, the ring gear is part of "ground", but I kept it open to either fix it or allow rotation based on a servo motor lock (on or off). I have done the same with the carrier. The sun is always the input to my/this system.

Kinematically, I can get the set to function properly and provide speeds that make sense, but I'm trying to get gear forces and loads out as well - that's where it doesn't play nice. I do have an issue with the kinematic analysis where I lock the carrier and let the ring gear become the output - this doesn't even solve. I have a few analyses created to play with - if anybody can figure out how to arrange the gear pairs to get these to work, that would be great. I know there will be redundancies for the dynamics, but that's what you get with more than 1 planet gear (although MDO seems to split the load evenly, as it should).

Way back in the days of Wildfire, we had Mechanica Motion to use. I actually provided input for the original gear specification/capability to Brian Shepherd when he was in charge of developing their simulation tools in the 90's. The code they produced was fantastic and even properly calculated an uncommon phenomenon called torque feedback in certain planetary transmission system arrangements...something tricky to do by hand...at least 20 years ago. Over time PTC has completely lost track of that older fantastic code that allowed us to arrange mechanisms that would handle very involved situations. I'm seeing this issue here - I used to be able to put together complex, linked planet systems, but now I can't get this simple, stand-alone one to work - SERENITY NOW!

"BEST PRACTICE" NOTE - for those of you interested enough to look at my model, please take note of the way I've documented the joints and gear pairs - I've provide proper names to them all for very easy recognition - a practice I seem to find very seldom among users - I highly recommend it.

Attached is a document created by Dr S. Shome, in response to your Planetary gears query. This deals with the kinematic side of things. Regarding the forces we will need more information.