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I have a 2D lidar mounted to a plate on a robot. I am looking for a method to adjust the pitch and roll of the plate so the plane of the laser is parallel to the ground.

Currently, I am using thin metal shims, but I want to find an easier method that will last. I was thinking about using set screws, but I've been told that it's a bad idea because they will inevitably come loose due to vibrations.

What other methods exist for adjusting the roll and pitch of a mounting plate? Are there any specially engineered solutions for this?

For reference, I'm using a Hokuyo 20Lx lidar. enter image description here

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  • $\begingroup$ Did you Google "Adjustable Mounting Plates" ? $\endgroup$ Aug 8 '18 at 23:42
  • $\begingroup$ Can the adjustment be manual or should it be automatic? If the latter, how quickly should it realign itself? $\endgroup$
    – Wasabi
    Aug 9 '18 at 1:01
  • $\begingroup$ @WilliamHird Yes I did. $\endgroup$
    – Klik
    Aug 9 '18 at 19:54
  • $\begingroup$ @Wasabi The adjustment should be manual since I don't want to use any sort of motors or over complicate the design. $\endgroup$
    – Klik
    Aug 9 '18 at 19:55
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A simple solution would be :

  • Two matching square plates with an M8 hole in each corner.

  • Sandwich a bit of moderately thick rubber, 10mm thick maybe, with matching holes between the two plates

  • arrange whatever mounting points you need for the lidar and vehicle in the top and bottom plates

  • Bolt through the holes with bolts any nyloc nuts

  • adjust the bolt tension to level the top plate, the rubber will take up the slack and

A slightly more sophisticated version is to drill a hole in the centre of the plates whcih you use to locate a ball bearing to act as a pivot point.

You could also drill through some (soft) ball bearings and use them as sort of spherical washers in conjunction with countersunk holes on the top plate to get better location for the bolt heads.

If you need a very large range of adjustment you could use something like this (made from modified pipe flanges) possibly substituting a bolt any nyloc for the Bristol lever, in fact with a smaller ball bearing (or no ball and a robber block or springs that is similar to what I described above. :

enter image description here

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  • $\begingroup$ I need very slight adjustment. I like the idea of using rubber but I'm not sure how long the solution will last for. I am unfamiliar with rubber and am not sure how it will hold up. What conditions might cause this solution to misalign? How robust is it? $\endgroup$
    – Klik
    Aug 9 '18 at 20:04
  • $\begingroup$ Neoprene or really any industrial synthetic rubber should be pretty durable in anything like normal conditions and will also give you a bit of vibration damping. Also with self locking nuts it should be pretty stable, nylocs are easily available and pretty stable but there are even more robust lock-nuts available and thread locking adhesive is also an option. You could also use compression springs instead of rubber $\endgroup$ Aug 9 '18 at 20:16
  • $\begingroup$ I think the concept you presented is the best one. I'll accept it as the answer. $\endgroup$
    – Klik
    Aug 9 '18 at 21:51
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You could order two large washers that are cut off a tapered plane, called beveled Washers. by rotating them over each other you get a level platform with ease. link

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  • $\begingroup$ This is a very interesting approach! Do you think this calibration method will withstand vibration? The solution should be maintenance free. $\endgroup$
    – Klik
    Aug 9 '18 at 19:56
  • $\begingroup$ Yes, given they are being squeezed down by by the main mounts. You check the washers, if they are too smooth you can sand them with 2000 grit sandpaper. $\endgroup$
    – kamran
    Aug 9 '18 at 22:03
  • $\begingroup$ @Kamran: Did you mean to say "Belleville Washers" instead of "beveled washers"? :-) $\endgroup$ Aug 9 '18 at 22:15
  • $\begingroup$ No i meant bevelled. Say you have to washers with an angle of a as taper. By rotatating them them over each other you can get a correction angle of 0 to 2xa aligned at your desired orientation. $\endgroup$
    – kamran
    Aug 9 '18 at 22:29

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