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Post by thetaker on Jul 7, 2019 13:15:51 GMT
I'm making CAD project for 6DOF platform. I want it as lightweight and compact as possible. Here's how it looks: www.youtube.com/watch?v=ud1lGghes1AWill this arrangement of motors work in real life? I wanted something similar to fullmotiondynamics.com/ ,but with cheaper motors and popular NMRV gearboxes. They are angled, not straight like in their design, so the arms will be perpendicular in comparison to the most popular 6DOF designs, where motors are far from center and use a lot of space. Attachments:
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ajwhirlybird
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my helicopter simulator - even the longest journey begins with the first step
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Post by ajwhirlybird on Jul 10, 2019 15:19:39 GMT
Hi thetaker, I don't think the design works that way! You don't get enough Yaw-movement with it. Can't you rotate the drive units so that the axle with the crank points outwards or inwards and the motor points upwards? Something like this: www.youtube.com/watch?v=3S92acr_5noor this link: servosandsimulation.com/  Best Regards a.j.whirlybird |
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Post by thetaker on Jul 12, 2019 19:24:33 GMT
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ajwhirlybird
New Member
my helicopter simulator - even the longest journey begins with the first step
Posts: 11
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Post by ajwhirlybird on Jul 12, 2019 20:04:37 GMT
Hi thetaker,
Really an unusual design, but it seems to work. I'm using a linear design and can't judge if the hexapod plugin can handle it. The best thing is to ask Thanos (tronicgr)...
Best Regards
a.j.whirlybird
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Post by thetaker on Jul 12, 2019 21:21:56 GMT
![]() I pushed the motors more apart from each other, so pushords make more triangle shape together. www.youtube.com/watch?v=WRYVKXJXDbc&Lower ball joints are placed more like in other popular designs. I don't know it works better or worse, just different. Does the direction of arm lever really matters? In the end, with linear actuators there are no arms, so I think theoretically software should handle this and there's no difference if arms are perpendicular or parallel. They are just changes in actuator length. I put it like this, because motors are large, and I really don't have that much space to use. I want it as compact as possible. Not even in vertical dimension. Attachments:
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ajwhirlybird
New Member
my helicopter simulator - even the longest journey begins with the first step
Posts: 11
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Post by ajwhirlybird on Jul 13, 2019 5:46:06 GMT
Sorry, we just had night in Switzerland.
I'm really not sure if this design works with the Simtools software. But it would be very compact!
Did you do your design with Solidworks? I work with SketchUp, but unfortunately I can't move it...
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Post by thetaker on Jul 13, 2019 7:33:33 GMT
Yes, Solidworks 2015. But I'm not an expert in this software.
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ajwhirlybird
New Member
my helicopter simulator - even the longest journey begins with the first step
Posts: 11
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Post by ajwhirlybird on Jul 13, 2019 8:09:30 GMT
After all, you managed to move the thing! I don't even know how to do that.
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ajwhirlybird
New Member
my helicopter simulator - even the longest journey begins with the first step
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Post by ajwhirlybird on Jul 13, 2019 8:15:38 GMT
I have placed your request in another forum. Maybe someone else will contact you who can help you.
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ajwhirlybird
New Member
my helicopter simulator - even the longest journey begins with the first step
Posts: 11
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Post by ajwhirlybird on Jul 13, 2019 8:18:29 GMT
Is it difficult to establish such a dependency between actuator and lifting cylinder? How much time would I need to get used to it? Is there a free Solidworks version?
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ajwhirlybird
New Member
my helicopter simulator - even the longest journey begins with the first step
Posts: 11
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Post by ajwhirlybird on Jul 13, 2019 15:21:32 GMT
Hi thetaker
I also found a solution for moving parts on SketchUp. It's called MSPhysics. So I have a new challege.
Best Regards
a.j.whirlybird
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ajwhirlybird
New Member
my helicopter simulator - even the longest journey begins with the first step
Posts: 11
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Post by ajwhirlybird on Jul 13, 2019 20:18:38 GMT
Hi thetaker, There are bad news from the community...  Thanos said: I wouldn't recommend worm gearboxes now that less expensive lead screw actuators are available. The worm gearboxes have backlash and usually are very low efficiency (50-60%). Leadscrew has efficiencies of 85% to 90%, and very low backlash (almost non existent). Google for lead screw linear actuators. I also saw two problems in your design: 1) Check if the ball joint would allow such large angles as in the video. 2) Due to the 90° mounting you have a torque on the axle of the worm gear. This means that the push rod does not act from above but diagonally on the axle. Only a few gearboxes allow this! The good news is that there are less expensive lead screw actuators are available and they also need little space.  Here is an example: www.xsimulator.net/community/threads/flypt-6dof-brushless-diy-actuators.10799/Best Regards a.j.whirlybird |
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Post by thetaker on Jul 14, 2019 9:55:04 GMT
I know about lead screws advantages, but building 6 actuators... with all this wiring mess. In my design I just plug 6 motors with integrated gearboxes to 6 VFD inverters, and all signals to AMC1280USB. Also why are those so f.... loud? I should make sealed casing for motors with lot of grease in moving parts, but I don't think it would help. Worm gears are simple solution and they are filled with oil so shouldn't be so loud. 1. I will make CNC adapters for each ball joint so they will have big movement angle. I don't have a photo of it, but it looks like inverted cone with smaller hole for screw inside. 2. This is something I never put into consideration, because I thought that in every position of platform, there is always some rod being in that 'bad' angle. But now I see from above, that in standard design the pushrods act directly from above in many positions. So i rearranged them. Still compact: Attachments:
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ajwhirlybird
New Member
my helicopter simulator - even the longest journey begins with the first step
Posts: 11
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Post by ajwhirlybird on Jul 14, 2019 13:40:23 GMT
Hi thetaker, It looks much better now!  But one problem isn't solved: the backlash of worm gears... Have a look at the different posts on this topic. Many have already bitten their teeth out... Best regards a.j.whirlybird |
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Post by thetaker on Jul 14, 2019 14:01:05 GMT
Is backlash really big problem? I don't want to sacrifice simplicity and quietness for less backlash. In the end I want my 6DOF more for flying, less for driving. I don't need much precision and small movements.
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