Auto-docking and charging

Hi! We’ve built a charging dock for our Stretch robot that ended up being similar to the one that Hello-Robot is developing. We’d like to share our design files with the community just in case anyone wanted to recreate it. We’ve been placing the charging docks in known locations and have been successfully able to send goal poses to the Stretch and dock/charge without issue.

A low-profile funnel-shaped dock sits on a stainless steel plate on the floor. A 3D-printed plate with 2 protruding disks is mounted to the bottom panel of the Stretch. We then added 2 battery terminals in the dock with a female barrel-jack that fits into the Noco charger, and 2 pieces of copper tape soldered to a cable that terminates into a male barrel-jack that fits into Stretch.

See comments for additional pictures.

We’ve since iterated on our dock design and added a cover for the 12V terminals.

Our bill of materials here

  • 3D printed dock, guiding base-plate, & terminal cover (see CAD link below)
  • Copper tape
  • Spade terminals (3mm bolt mouth size)
  • Battery contacts
  • 18" x 18" steel base plate
  • M2.5 screws (for battery contacts)
  • M3 screws (for terminal cover)
  • 18 AWG wire, high-temp hot glue & high-temp glue gun, solder, UHMW tape

Feel free to check out our CAD here for the 3d printed parts.

If you plan to build one:

  • The front disk on the guiding base-plate should be centered in the axis of the drive wheels.
  • We ended up cutting a slot in the rear disk to pass the wires through because they were getting pinched between the guiding base-plate and the docking station while in the configuration shown in the pictures above.
  • We recommend using UHMW tape (or other low-friction tape) on the steel base plate so the wheels will easily slip when the robot pushes against the docking station.
  • The robot can still cause the entire docking station to slide when it hits the back of the slot. We suggest docking at lower speeds (0.1 m/s or less) and/or taping the base plate to the floor.
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Guiding base-plate side-view:

Guiding base-plate front-view:

Guiding base-plate mounted on Stretch:

Docking station detail:

Updated CAD with terminal cover:

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Welcome to the forum @mauger! It’s extremely cool to see your take on a charging docking station. Thanks for sharing it with the community!

I’ll be building one for myself to test it out, and I’m sure it will be of interest to other Stretch users too.

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Thanks bshah!

Here’s version 2: