Houston - Lidar Mount V2

Task Description

Design and manufacture a 360 lidar mount for Houston. Some tips for design:

• increase 3D print infill if the design will be 3D printed

• could explore using aluminum sheet metal which is stronger and can be lighter than 3D prints

Open

V1 of the Lidar Mount. The black equipment is the lidar.

Open

Try to use these mounting holes

Constraints

Relevant Contacts

Assignees

Task Progression/Updates

Author: @ person updating Date: YYYY/MM/DD

UPDATE TITLE

Include any updates here + reasoning

Author: @Nathaniel Li Date: Feb 4, 2024

Initial Design

• I’ve made an initial design using sheet metal for the Lidar mount while attempting to keep it as simple as possible

• Not too sure about material and gauge thickness

Author: @Smile Khatri Date: Feb 4, 2024

Design Review 1:

• I agree with keeping the design simple as possible. This is a pretty cool initial design but we will run into some manufacturing constraints

• It might also be tedious to bolt the mount onto Houston because the bottom flanges are facing inwards but on the other hand, folding it inward will make the design slightly more compact (I’ll leave it up to your discretion)

• The sheet metal bender in E5 cannot bend a metal into a C shape. Refer to my drawing:

Here’s an idea that I had, feel free to use it or disregard it if there’s a more optimized design. I think S-shaped is okay since the mounting hole flange is pretty small.

• As for material, 5052 aluminum is the best and it’s super cheap. I think for thickness, 0.064” or .051” would be good but I will consult with Alison and Conall on this as well.

   

Author: @Nathaniel Li Date: Feb 4, 2024

Revision 1:

• I’ve redesigned the mount to be two pieces to (hopefully) overcome manufacturing constraints

  • I’m not sure if we’ll need a 3D printed piece to hold the two pieces together as it can be directly mounted to both Houston and the Lidar?

• For now, I’ve decided to keep the mounting hole flange faced inwards for compactness

  • I’m not sure if this is manufacturable due to the C-shape that you mentioned Smile? If not I can change it to have outward facing flanges as described below

    • To have them face outwards, I’d have to shift them to the adjacent side due to the hole locations as both the Houston holes are 38mm x 62mm and the Lidar holes are 38mm x 38mm: currently the flanges are in line with the 38mm side so that’s why they’re facing in

    • I would have the flange moved to the adjacent side (ie. the 62mm side) and that could work, I’m just not sure about clearance as the old mount had the mounting holes on the 38mm side

    • I can explain this more in the meeting

• I’ve chosen for now to go with 5052 aluminum at 0.064” (weight savings) but I believe this needs to be confirmed

Author: @Smile Khatri Date: Feb 5, 2024

Design Review 2:

• Very nice

• I would recommend making the legs a little wider (right now they are 0.5 cm). In the event that the drone performs a hard landing the wider area will be able to withstand more force (and also more area for stress when we bend it). I would say up to 1cm would be good.

• Flanges inside seem reasonable to me it’ll keep the design simple. You are right we don’t need a 3D print. I think I had that there because I don’t want the LiDar to get ripped apart incase the mounts somehow try to move away from each other the print would take on that stress but this is prob too much.

• When we water jet the current model, I feel that we’ll be wasting a ton of sheet metal. I.e., if you water jet the skinny legs, you’ll have a big rectangular piece of metal wasted. Maybe we can add some connections b/w legs, like a X connecting two legs (feels like that would make it more rigid and looks cool). Maybe do weight analysis, if it adds a significant amount of weight then probably ditch this idea.

Author: @Nathaniel Li Date: Feb 6, 2024

Discussion During General:

• Decided to go with both a 1 piece and 2 piece design and try both (ie. if manufacturing for the 1 piece doesn’t work, we have an alternative).

• The 2 piece design will have an additional connecting plate so that the Lidar isn’t the only connection.

• Thicken the legs (to 1cm) and have at least 1 diameter of clearance around holes.

Author: @Nathaniel Li Date: Feb 7, 2024

Revision 2:

• I implemented all changes from the discussion above:

  • Leg thickness increased to 1cm

  • Holes have more clearance

  • Created both a 1-piece and a 2-piece design

• The 2-piece design would also require a connector to support Lidar

• Assembly can be found in H24_LIDAR_A001_V2.1_MOUNT

• Important to note that the connector is a 50mm x 50mm piece of sheet metal that can be fabricated from a 52mm x 50mm piece when the mount is created (ie. reuse cut material for the connector)

• The 1-piece design would probably be the best bet if it can be manufactured (easiest to mount)

• Assembly can be found in H24_LIDAR_A002_V2.2_MOUNT

• In total to make each type of mount fully, we need 2 x (85mm x 85mm) + (85mm x 165mm)

  • This includes an additional 1/2 inch on each side to mount when water jetting

Author: @Smile Khatri Date: Feb 9, 2024

Manufacturing Review:

• Add cheese holes to the design to reduce weight and make it easier to bolt the mount to the Houston PCB

• Make legs a little bit thinner so they do not touch the pixhawk

• A small square cut out can be added to the edge so that the hex key can be vertical when tightening the screw. We can also shorten the legs because there is still a lot of clearance between the Pixhawk and the top plate ~ 18mm at the moment. We can probably reduce it by around 5 mm. This way there won’t be interference when making the C shape.

Author: @Nathaniel Li Date: Feb 11, 2024

Revision 3:

• @Merek Lohnes did some good work by adding some weight saving holes

  • These holes also should make mounting/screwing it onto Houston easier as the hex keys should be able to go straight down through them

• Thinned the legs to give an extra 2mm of clearance between them → Should prevent any contact with the Pixhawk

• Reduced the leg lengths by 5mm so they're down to approx 3.5cm now