We split this thread from Kåre’s T-Hex thread. Didn’t want to junk it up.
Edit: For those just starting this thread. This bot was originally designed by Kåre Halvorsen as a 4DOF hexapod. This thread covers my process of making it into a 3DOF kit. It’s inspired by Kåre’s original T-Hex! Thanks Kåre!
Here is a first draft prototype of the chassis. I’m using lexan for now, but it’s only a prototyping tool. This chassis must be made from aluminum to be strong enough. I will likely make several changes, but I think it already looks pretty nice. Feedback…
Awesome, its even better than the original! 8)
Again, I wish I had a cnc…
But I think the one spacer on top might be a possible conflict if you want to mount an ASB bracket inside the the body using the SES holes. Whats the distance between center of the SES hole/pattern at top and to the upper part of the BB2/SSC32 boards?
The dimensions are pretty much the same as yours. I move the SES hole pattern forward about half an inch. This allowed me to add a crossmember there and remove the one that conflicted with the Bot Boards DB9.
The answer is about 0.922". sorry, converting from mm to inches leaves some weird results. I think I will move it forward a bit more to clear the crossmember better.
More images maybe tomorrow. Run out of time. Thanks for the comments.
Dimensions in inch are ok for me, I’m using a digital caliper that show both mm and inch, so its pretty easy to visualize.
Ok thats about the same distance I have. But I’ve been thinking if it should be possible to mount ASB + C bracket inside the body (rotating turret?) then this distance should be increased to about 30mm = 1,181". Moving the SES hole even further forward worries me a little when it comes to COG though.
Kare, Rather than move the SES holes forward, I can move the crossmember backwards a little. I’m not sure how you mean to add the ASB-04 and C bracket inside. I’m having trouble visualizing it in my head.
I’ll try to explain; an ASB-04 with the C-bracket mounted on it. Then mount the ASB-04 between the two body panels using a hub or some crossmembers between the ASB-04 and one of the body panels. Then you’ll get a solid rotating base for a turret or something. Just an idea.
Yeah, i like that idea too Mike!
Oh, another thing. I’ve been thinking of mounting one sharp IR sensor on each side of the body panels. Maybe an extra hole on the very top? The sharp sensor could share the mounting hole of the front/top crossmember and then we just need an extra hole on the other side for mounting the sensor. Then again, it isn’t that hard to drill a single hole or two for those who want to do that.
Hi Kåre, Yeah that’s what I thought you were saying. I’ve tested many fits and configurations, but two drawbacks. The first is the turret would need to be offset to one side in order to have enough room for the C bracket to rotate. The second is you must use the short C bracket so the range is limited to around 125°. I’m investigating some other ideas for a turret.
Ah, yes I see that. At first I was just thinking of using the ASB-04 without the C-bracket, but that wouldn’t be that stable I think. Maybe another kind of support? To be honest I’ve not put my mind to it very much. i’m looking forward what you can come up with for the turret.
Another but more heavy solution is to use two individual turret on each side? That could be done on a 3DOF leg version though…
I’m planning of using a sonar + IR sensor on the 2 DOF head at the front. The relative high body should be very suitable for mounting different sensor without have the legs in conflict with the sensor beam.
If you were to move the SES holes on the sides down a bit, there would be a possibility of using this chassis to build either a walker or a wheeled rover. On could attach an ASB-06 to each of the side holes and attach MMT-03 motor mounts to that, or some similar arrangement.
I spent the weekend working on this chassis design. I started by drawing what I already had, and moving things around quite a bit. My goal was to move the boards up enough that their mounting holes were above the level of the top of the “C” brackets. This would allow adding more SES hole patterns at the bottom which would make a lot of things possible. By moving the boards back a bit they would become centered above the middle legs. This will make the servo wires fit more evenly. A few hours later I had erased so much from my graph paper it was curling up at the edges. At this point the chassis is looking less “truck” like and more “helicopter” like in appearance. I’m attaching an image later today. It’s going to be able to have 4 or 6 legs, standard 4WD, articulating 4 wheel steer rover, and tracks. Ok, ok, I know… enough bla bla, show us the pictures. Working on it.
Ok I’m adding pictures of the chassis redesign in a few minutes. Here are some images of the 4 wheel steer idea. It looks like an interesting math problem, making the wheels rotate in conjunction with the servos, so they don’t fight each other. Will be needing a pair of dual channel motor controllers that can read encoders, so motors can be controlled at accurate rpm’s. The RoboClaw 2 x 5 will work.
