Robobot hardware: Difference between revisions

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[[File:robobot-design-2024.png | 400px]]
[[File:robobot-design-2024.png | 400px]]


==Mounting holes==
All 3D-printed parts are designed in Onshape and are public.
They can be accessed at
https://cad.onshape.com/documents/fef8699fcafb8aea780c8981/w/ce38e7fdd6cf8533b65e2c3c/e/eefdcf481faf2a4b03f5058c
A browser-only CAD tool.
 
For students, a free account can be created at https://www.onshape.com/en/education/
 
All items can be exported (in e.g. step format) for import in other CAD tools.
 
==Screws==
 
===Mounting holes===


The hardware is 3D-printed plastic (except for the electronics and screws)
The hardware is 3D-printed plastic (except for the electronics and screws)
Line 14: Line 25:
* Plastic thickness is 6mm in most cases.
* Plastic thickness is 6mm in most cases.


==Screws for plastic (PT-screws)==
===Screws for plastic (PT screws)===


Mounting items on the 3D printed plastic should use plastic screws.
Mounting items on the 3D-printed thermoplastic should use plastic (PT) screws.


Plastic screws:
Plastic (PT) screws:
* Cut into the plastic with a sharp thread.
* Cut into the plastic with a sharp thread.
* Gets locked in the plastic and will not shake loose.
* Gets locked into the plastic.


PT-screw selection:
Plastic (PT) screw selection:
* Pan-head 3mm diameter and length:
* Pan-head 2.5mm for PCB mounting, length 8mm, Torx 8IP/TX8.
** 6mm, 10, 14mm, 18mm
* Countersunk 3mm length 10mm, TX8, for the most plastic-plastic mount, where head height is important.
* Countersunk 3mm
* Pan head 3mm, length 10mm, TX10, for the most plastic-plastic mount, with space for the head.
** 10mm, 14mm
* Pan head 3mm, length 16mm, TX10, for servo arm 'axle'.
* Countersunk 3mm, length 25mm, TX8, box lit 'bearing' and camera mount.


==Screws for metal==
[[File:PT-screw.png | 300px]]
 
A typical pan head screw for thermoplastic.
 
===Screws for metal===


Mounting of motors and other metal parts should use  
Mounting of motors and other metal parts should use  
Line 34: Line 50:


Metal screw selection:
Metal screw selection:
* M3 pan head
* M3 pan head (For servo horn, 16mm, Torx TX10)
* M3 countersunk (for e.g. motor mount)
* M3 countersunk (For motor mount, 12mm, Torx TX10)
* M6 bolt, length 40mm?
* M5 bolt (For the main wheel fastener, 16mm, Hex/Umbraco 4mm)
* M5 nut (For the main wheel fastener).
* M6 bolt (Castor axles, length 50mm, Hex/Umbraco 5mm)
 
==Axles==
 
Castor wheel axles are made from
* 2mm piano wire, length 25mm (e.g.: https://www.hobbydirect.dk/shop/modelskibe-af-trae/tilbehoer/piano-traad-pianotraad.htm).
NB! This is hardened steel and can not be cut by normal cutting tools, use e.g. a Dremel cutting disk.
* 6mm bearing flange for castor, IGUS iglidur M250 flange bearing MFM­0610­10
 
==Camera==
 
The used camera is a 'Jieli Technology' camera of type 'USB PHY 2.0' (packed by Sandberg as 'USB Webcam 1080P').
 
The camera has limited control capabilities but supports the following data formats.
 
* MJPG coded 640 x 320 pixels at 25 or 30 FPS
* MJPG coded 1280 x 720 pixels at 25 or 30 FPS
* MJPG coded 1920 x 1080 pixels at 25 or 30 FPS
* MJPG coded 640 x 480 pixels at 25 or 30 FPS; this mode cuts parts of the image width to fit the format
 
It also supports "raw" format as YUYV 4:2:2, but it seems like data loss occurs (fragmented images), so do not use this format.
 
==Servo==
 
The used servo is
* Savox SA-1230SG https://savox-servo.com/en/product/SA-1230SGplus/savox-servo-sa-1230sg-digital-coreless-motor-steel-gear
 
==Distance sensor==
 
For distance measurement is used
* Sharp 2Y0A21 (7-80cm) https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&ved=2ahUKEwiHpKfkgJGDAxX2h_0HHXSFCHIQFnoECBIQAQ&url=https%3A%2F%2Fglobal.sharp%2Fproducts%2Fdevice%2Flineup%2Fdata%2Fpdf%2Fdatasheet%2Fgp2y0a21yk_e.pdf&usg=AOvVaw2UFFgiLXC0mH_S1Q3VeqdZ&opi=89978449


Most screws for metal have a Umbraco (Allan) type drive.
== Motor ==


== Screw drive type==
The motor is CHP-36GP-555 from https://www.airsoftmotor.com/encoder-motor/planetary-reducer-with-encoder/micro-dc-planetary-gear-motor-with-encoder.html


We could unfortunately not standardize on one type of screw drive type
12V with gearing 19:1


Drive types used:
Encoder with 17 magnets, i.e. 68 pulses per revolution.
* Umbraco or Allan-type: plane hexagonal drive and tool (mostly 2, 2.5, 3, 4mm)
* Cross PH (Philips type) is not used much (size PH0, PH1, PH2).
* Cross PZ (Pozidrive) is the most common for cross-drive (size PZ0, PZ1, PZ2).
* 6-lobe or (Tork) (size T10, T15, T20)

Latest revision as of 14:40, 4 January 2024

Back to Robobot B

Hardware

All 3D-printed parts are designed in Onshape and are public. They can be accessed at https://cad.onshape.com/documents/fef8699fcafb8aea780c8981/w/ce38e7fdd6cf8533b65e2c3c/e/eefdcf481faf2a4b03f5058c A browser-only CAD tool.

For students, a free account can be created at https://www.onshape.com/en/education/

All items can be exported (in e.g. step format) for import in other CAD tools.

Screws

Mounting holes

The hardware is 3D-printed plastic (except for the electronics and screws)

All 3D printed parts have holes for mounting additional parts. These holes have:

  • Individual hole distance of 1cm.
  • Hole diameter of 2.5mm, intended for 3mm plastic screws.
  • Plastic thickness is 6mm in most cases.

Screws for plastic (PT screws)

Mounting items on the 3D-printed thermoplastic should use plastic (PT) screws.

Plastic (PT) screws:

  • Cut into the plastic with a sharp thread.
  • Gets locked into the plastic.

Plastic (PT) screw selection:

  • Pan-head 2.5mm for PCB mounting, length 8mm, Torx 8IP/TX8.
  • Countersunk 3mm length 10mm, TX8, for the most plastic-plastic mount, where head height is important.
  • Pan head 3mm, length 10mm, TX10, for the most plastic-plastic mount, with space for the head.
  • Pan head 3mm, length 16mm, TX10, for servo arm 'axle'.
  • Countersunk 3mm, length 25mm, TX8, box lit 'bearing' and camera mount.

A typical pan head screw for thermoplastic.

Screws for metal

Mounting of motors and other metal parts should use screws for metal.

Metal screw selection:

  • M3 pan head (For servo horn, 16mm, Torx TX10)
  • M3 countersunk (For motor mount, 12mm, Torx TX10)
  • M5 bolt (For the main wheel fastener, 16mm, Hex/Umbraco 4mm)
  • M5 nut (For the main wheel fastener).
  • M6 bolt (Castor axles, length 50mm, Hex/Umbraco 5mm)

Axles

Castor wheel axles are made from

NB! This is hardened steel and can not be cut by normal cutting tools, use e.g. a Dremel cutting disk.

  • 6mm bearing flange for castor, IGUS iglidur M250 flange bearing MFM­0610­10

Camera

The used camera is a 'Jieli Technology' camera of type 'USB PHY 2.0' (packed by Sandberg as 'USB Webcam 1080P').

The camera has limited control capabilities but supports the following data formats.

  • MJPG coded 640 x 320 pixels at 25 or 30 FPS
  • MJPG coded 1280 x 720 pixels at 25 or 30 FPS
  • MJPG coded 1920 x 1080 pixels at 25 or 30 FPS
  • MJPG coded 640 x 480 pixels at 25 or 30 FPS; this mode cuts parts of the image width to fit the format

It also supports "raw" format as YUYV 4:2:2, but it seems like data loss occurs (fragmented images), so do not use this format.

Servo

The used servo is

Distance sensor

For distance measurement is used

Motor

The motor is CHP-36GP-555 from https://www.airsoftmotor.com/encoder-motor/planetary-reducer-with-encoder/micro-dc-planetary-gear-motor-with-encoder.html

12V with gearing 19:1

Encoder with 17 magnets, i.e. 68 pulses per revolution.