help needed with Pick-and-place animation

Hi,

There's a specific sequence of events that I'm attempting to animate in Inventor Studio: A mechanism (almost always a robotic arm) which travels to a certain location, picks up an object, travels to another location, and drops it there.

Here are a few examples of what I mean:

It seems that in order to do this you'd have to enable and disable constraints during the animation timeline, but I don't see how.

Right now I'm "cheating" and creating multiple instances of the object that I need to move -- two of which are faded out and one that's visible. When the gripping mechanism reaches the first location, the object at that location vanishes and an object that's constrained to the gripping mechanism becomes visible. This remains the case until it reaches its destination, at which point the object connected to the gripper fades out and the object at the destination fades in.

Surely there's a more elegant way of achieving this, but hours of googling haven't come up with an answer.

Thanks for any advice.

I managed to forget an important detail: I'm looking for a way to do this without pos reps. Right now I have the entire mechanism driven with/by parameters -- this makes changing event times and copying/pasting animations very simple and fluid. When I add pos reps I almost always have to make sure that nothing else is happening at the same time, otherwise it's just a matter of time until something breaks.

If I understand correctly, the way to do this with pos reps is to make three sets of constraints: start position (constrained to whatever's holding the object), transitional (remove the first set of constraints and replace it with a set which ties it to the robot arm), and last (remove the transitional set and activate the last set which positions it at the final position). I then have to sync these events with the motion of the robot arm. This works, but the result is rigid and changing anything later is almost impossible (it takes less time to redo the entire process). If I try animating anything but the camera while pos reps are being animated, it either throws some error (usually about over-constraints), or objects start "skipping" all over the place.

I'm thinking that the only other way to do this is through simulation, which I'm trying to avoid since it over-complicates everything. Is there another method?

I'm thinking that the only other way to do this is through simulation, which I'm trying to avoid since it over-complicates everything.

I would use Dynamic Simulation and Publish to Studio - but that assumes knowledge of a whole different toolset.

I thought I'd follow up in case anybody Googles this particular question:

JD Mather's solution is probably the quickest, requiring the least amount of steps. You can define the gripping points in the geometry itself and let the simulation do the work for you.

However not everyone has Inventor Pro, and it is possible to pull this off without pos reps: First, create three sets of constraints for 3 locations of the object being moved: start, transition, and end (this is what I described in the first reply). Instead of using pos reps, however, keep using parameters to move the robot arm. When the gripping mechanism reaches the destination, use the "animate constraints" to deactivate one set of constraints and activate the next one (yes, I knew this was possible, but it seemed messy at first). In order to keep the timeline "readable", name every one of your constraints, something like "Object1 - Start", "Object1 - Gripped", "Object1 - Destination". If you don't, it'll be almost impossible to understand what's going on (especially for somebody else who wants to review/maintain the animation).

Suppressing and un-suppressing constraints is an instantaneous event, and you can do both in the same frame (in fact, you should, otherwise you'll have unconstrained objects for 1 frame, and Inventor could decide to toss them anywhere).

This isn't the most elegant of solutions, but it works, and you get the flexibility of being able to resize transition times, as well as using copy-paste on animation events to speed up the setup time. Also, if you have sub-assemblies, you can access their parameters from Inventor Studio by exporting them (you can also have sub-assembly pos reps, but inconsistent behavior is almost certain if you try to animate them).

The real take-away for me was: do NOT use pos reps unless they're very straight-forward and it saves you a lot of time. If you try to animate anything alongside a pos-rep animation it'll almost always mess things up.