Assembling the FRC Andy Mark base

[matthewgkerr]

I have been following Phil's assembly tutorials and have hit some sticking points. I have raised these questions to Phil but I thought I would ask for some feedback from the wider community.

1. I noticed that when you placed the wheel on the frame, you used two of the same sized spaces. The instructions for building the frame actually uses two different sized spaces. I only noticed because I inserted the spacer by attaching to the bearing, instead of the frame. Was this intentional?

2. The frame instructions gets you to build wheels with different hub configurations; one on the outside, another on the inside and the middle wheel with two hubs. You placed the single wheel assembly in all six positions. Was this intentional?

3. Following your instructions, I created the wheel axle assembly and copied it to another location. I found that some additional constraints break (other than those you mention... I think). When I attempt to spin the wheel on its axis (once i enable flexible), the wheel and one of the spacers move and are no longer attached to the axle. I'm wondering if instead of mating the wheel axis to the axis of the hole in the frame, should i instead mate it to the axis of the bolt, as well as mating the axis of the bolt to the axis of the hole?

4. I have created all the wheel configurations (manually because I got stuck on the previous problem) and got to the point of constraining a face of a hub (the wheel with two hubs) to the frame, but I got a dialog with three errors saying "constraint cannot find component reference". Now I'm really stuck. How should I proceed?

5. I also wasn't sure what to do about removing the bearings from the wheel assembly. Did you create new copies of this assembly, or did you remove the bearings from the original assembly? I think you must have because when I created new wheel assemblies (see previous) I edited the original wheel assembly, deleting the bearings when necessary. When I go back to previously created assemblies, their bearings are gone. Because all my wheel assemblies are using the same base wheel assembly. Should I be creating copies of the KOP wheel assembly? i.e. a wheel assembly with no bearings?

Thanks.

[matthewgkerr]

Ok, well I figured out why I was getting stuck with #4. When I created the wheel/axle assembly, there was a constraint with the frame which was causing an issue. I assume I need to keep this broken constraint and repair it by associating it to the hole in the frame in the new location? But I'm not sure how I go about doing this. To get past the problem, I just deleted the constraint, but I'm sure that I have now broken all my wheel/axle assemblies. Help please.

[matthewgkerr]

I have gotten a little further and have some additional questions...

1. Should I be using the drive system STEP files provided by Andy Mark instead of building the assemblies from the Inventor Kit Of Parts?

2. When building the Toughbox Mini (CAD), I have noticed that the Clip Ring is too big. I had a closer look at the sketch and it appears that the inner radius of the ring is roughly the same as the diameter of where it connects to the output shaft. i.e. the ring is twice as big as it should be. Is the part incorrectly size or do I need to (somehow) shrink it down to size?

3. I am placing the lock nuts on the Toughbox Mini. I can insert them easy enough. What I'm unsure about is how to make the nut sit nicely within the hex shaped hole?

4. Also, when placing a hex gear on a hex shaft, I have been mating the face of the shaft to the bearing, then mating two of the hex faces of the gear to two of the hex faces of the shaft. Is there an easier way to insert the gear on the shaft such that Inventor automatically fits the hex hole over the hex shaft? i.e. so I don't need to mate the faces of the hex hole and shaft.

Thanks.

[inventor_phild]

Matthew,

Let’s see if I can resolve some of your questions.

Question Set 1

1. Spacer size. As noted in my video, I placed 2 spacers of the same size, but will resolve the final design when I add the Toughbox and motors. This should be finished by Monday for my next blog entry.

2. Wheel assembly. Yes, I created a standard wheel assembly and placed it 6 times. Again, I will modify when I complete the drive system with the belts.

3. Broken constraints. I only got the one broken angle constraint as noted in my video. If this becomes an issue, then I would build the wheel assembly separately from the frame, place it in the main assembly, and then make it flexible.

4. Looks like you resolved this one.

5. Deleting the bearing. I opened the wheel assembly with two bearings, deleted one bearing and saved the assembly. Since the bearing is part of the KOP it is easy to add or remove bearings.

Question Set 2

1. All my models are based on the drawings or files provided by AndyMark. The STEP file assemblies from AndyMark will probably not have any constraints, so each part will be free to move anywhere. You can ground all parts to resolve this. If you need the assembly now, use the STEP file provided by AndyMark. My Inventor version is being built as part of my webinar series. As noted earlier, it should be ready by Monday.

2. I will check the clip ring size.

3. If I understand correctly, I would place an angle constraint between a face on the locknut and a face on the Toughbox to align as you want.

4. Mating the hex faces. Yes and no!! Your work flow is correct and does involve repeating the same steps, so when that happens I always look for a quicker solution if I know I will be doing the same work flow over and over again. For future reference, look at iMates. This adds one half of the constraint to one part and the other half the other part. When you insert a part in an assembly, it automatically assembles itself. Very cool, but not used often enough. If time permits I can add an example to one of my webinars.

[matthewgkerr]

Thanks Phil for your responses and webinars. They have been very useful and I can't wait to see more. I was wondering if you have had a chance to look at the clip ring size?

[inventor_phild]

Matthew,

Yes, I have attached a revised part. Let me know if that works for you.