The Prototyping of milli is moving - as well as Milli, its self!
The focus since the last post was to find and fix any binding parts of the tread tracks. I have located a specific tread that was not flexing properly, due to it being part of the v3 design and connecting to a v4 tread. I am using screws to act as 'pins' in the track to connect treads together. This is not a good practice as the tread of the screw can bind with the tread. however, if significantly bored out it is permissible at this stage of development.
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| Milli OpenSCAD - for 3rd prototype test 16 Feb 2020 |
The other change was to adjust the design of the horizontal stabilizing arm. This arm converts the spinning helix motion to a moving sine wave. Thus it is essential to the design. Changes included shortening the arm by 8mm and increasing the opening by 4mm. I also noticed that the first tread was binding with the arm, and adjusted the tread to move more freely.
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| Milli - ready for static testing, full tread length, 18v battery, messy desk(!) |
The result - the track moves freely! At least in the initial trials when I applied 18V to the motor it worked well. I then removed the frame holding the chassis and a quickly put together a simple axle and wheels. This was made by a thin rod and some plastic gears salvaged from a printer. I used alligator clips to hold the wheels in place. I put the robot drive on some carpet for friction and Viola! - the worm drive works!!
Next steps:
- Find that nagging binding point seen in the video
- Thinking on the chassis and covering. How the heck am I going to get a battery on it?
- New tread design with increased movement
- Ability to move on smooth surfaces
