20230508 Tuning In the O-Ring Size

 

Parker handbook 

4.3 Face Type Seals

“Face type seals are sometimes rectangular. In designing such

a seal to receive a standard O-ring, the inside corner radii of

the groove should be at least three times (ideally six times) the

cross-section diameter of the O-ring to avoid over-stressing

the ring or causing corner creases that would potentially leak.

”

The cross section of the o ring is 0.139 inches

The minimum internal bend radius is 3*0.139 = 0.417 

This had to be adjusted within the design

Page 4-18 in the parker handbook

Page 4-25 in the parker handbook

Diametral clearance. 

The O-ring we are looking for has a dash number of 255 

5.609 + 0.005 = 5.614

20230507 Blender Exploration of Camera Placement

 

Main changes, setting all of the fusion 360 models to meters before exporting. The FOV of the camera looks more realistic. 

Shift+s for moving 3d cursor to selected geometry

• Allows us to import a camera directly onto the modeled camera within blender

Front view of where the grippers would go (small claw full extension) (large claw, restricted extension

Downward facing camera

Suggested view for the external camera

External camera pointed towards the gripper from the back of the sub

“shift  + h” isolate all except selected

“Alt + h” show all

“H” hide selected

Bottom facing camera with the larger gripper completely extended

Left: bottom view of the camera

Right: front view of the sub with the gripper extended all the way down

20230506 Playing around with FOV of the Camera in Blender

 

Importing sub into blender as a .obj model 

Zoomed in view of camera object in blender placed on modeled camera

Placing the 

Note “ctrl+L” to select the paired vertices, allows to delete the entire object in the blender obj file type

“Ctrl + alt + 0” locks the camera to current view

“0” change view to camera view

“5” changes from orthographic to perspective view

3 side view

9 opposite view (if looking bottom from top, switches to looking up from bottom)

7 top view

Be sure to click on the camera to bring up the camera properties

Utilizing the camera properties here

DFOV / HFOV / VFOV

81° / 69° / 55°

Using this forum post to size correctly here

Currently we see that the gripper is not in view of the camera when stowed

“Alt + z” for x ray view

“X” delete tool

Note when importing .obj files into blender set the model dimensions to meters, here the dimensions in blender scaled 1 inch to 1 meter

“Shift z” goes to wireframe

Side view with the lid mission about 25 inches from bottom of the sub. Note with the incorrect units while exporting from fusion to blender the FOV is incorrect.

This is what the bottom facing camera may see when the top of the bin is about 25 inches below the sub. Note not accounting for the color change from the water

Current settings of the camera: (note treating 1m as 1 inch and applying the proper conversions)

20230503 trying to implement solution that surrounds the existing solution

 

Reference here

AS568 Series	O-Ring Cross-Section		Gland Depth (D)	Squeeze		Gland Width (W)				Gap (H)	Gland Corner Radii
	Nominal	TOL (+/-)		Actual	Percent	Nominal	TOL (+/-)	w/ 1 Backup Ring	w/ 2 Backup Rings	MAX	R1	R2
-0XX	0.070	0.003	.050-0.052	.015-.023	22%-32%	0.095	0.002	0.140	0.207	0.002	0.007	0.005
-1XX	0.103	0.004	.081-.083	.017-.025	17%-24%	0.142	0.003	0.173	0.240	0.002	0.007	0.005
-2XX	0.139	0.004	.111-.113	.022-.032	16%-23%	0.189	0.003	0.210	0.277	0.002	0.017	0.005
-3XX	0.210	0.005	.170-.173	.032-.045	15%-21%	0.283	0.003	0.313	0.412	0.003	0.027	0.005
-4XX	0.275	0.006	.226-.229	.040-.055	15%-20%	0.377	0.003	0.410	0.540	0.003	0.027	0.005

Planed o-ring here

Try2 here

Ideating the radially sealing insert to interface with electronics enclosure:

cross section of blue trail engineering connector and cable grip

ISO view of radial plug and cable grip

Problem with this design is that there is barely any clearance for taking on and off the

Inspiration from SDSU robosub team here

20230604 Simmutation And Lightening

 

1MPa applied to the box ~ the pressure experienced around 5 meters.  This material removal cuts down the weight of the camera enclosure from 2.69 lbs to 1.59 lbs. Almost a 50% reduction in weight

Thinning out the walls, 

0.65 wall thickness

0.195 wall thickness

20230103 Second Version of Camera Enclosure

Using sealing m4 screws to mount oak-d onto back here

Thinking about a male usb-c breakout board to enable usage of cable without cutting and resoldering cable back together in current design. 90 degree usb cable would have to be cut and resoldered as the right angle connector will not fit through the gland. Another consideration is that if the usb cable is nicked or damaged water will leak through the cable into the camera due to the lack of insulation in the cable. 

Internal mounting plate. This design includes a secondary plate that can be machined out of aluminum or laser cut.

Changed from flat head screws to socket head screws for less change of stripping the head. Additionally increased the width of the enclosure to enable easier access to screws

Curving the outside to have screws same distance away from the 

Decision: 

Are we picking this waterproof version or will we go custom: “OAK-D-POE Development Kit with PoE Feature, OpenCV AI Machine Vision Kit, IP67 Waterproof”

Custom o ring length = 3.75 in*2 + 1.892 in*2 + 0.491 in*4 = 13.24800 inches in circumference (center line)

Compress down into a ⅛ by 1/16 profile

Blue robotics o-rings are “Nitrile Rubber (Buna-N)” seen here

3d prints are not waterproof source

Suggestions to waterproof container here