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Update: Remember my post about upgrading the plastic joints on the Berkeley Lite? The CNC cycloidal parts just arrived.
Hey guys. A couple months back I asked this sub for some reality checks on using a 30:1 metal cycloidal to replace 3D printed joints for QDD. The first batch of CNC parts finally showed up. I was honestly expecting the tight machining tolerances to make it bind up, but turning the output flange by hand... the back-drivability is wild. Just for context: we were getting super annoyed with stripping the 3D-printed plastic gears on open-source rigs like the Berkeley Lite and ALOHA. They are awesome projects, but the plastic joints are fragile and a nightmare to maintain. So we designed this as a drop-in replacement (calling it the Starfruit Actuator). Instead of printing two different plastic joint types, we wanted a single unified metal design to simplify the BOM and actually survive dynamic loads. Specs we're rolling with for the final drop: 30:1 ratio (30 teeth, 31 pins) Dual absolute encoders (supports FOC & MIT modes) Fully ODrive-compatible Target price: ~$149 Next up is integrating the motor and driver board, then throwing it on the test bench to see if it survives a 76 Nm torque test without exploding. Fingers crossed lol. Let me know what you think of the machining! All the STEP files, ROS2 nodes, and configs are going to be 100% open source. I'll drop the project link in the comments if anyone wants to track the testing or grab the files when they go live. submitted by /u/External_Wasabi9131 [link] [Kommentare] reddit.com · reddit.com
Hey guys. A couple months back I asked this sub for some reality checks on using a 30:1 metal cycloidal to replace 3D printed joints for QDD. The first batch of CNC parts finally showed up. I was honestly expecting the tight machining tolerances to make it bind up, but turning the output flange by hand... the back-drivability is wild. Just for context: we were getting super annoyed with stripping the 3D-printed plastic gears on open-source rigs like the Berkeley Lite and ALOHA. They are awesome projects, but the plastic joints are fragile and a nightmare to maintain. So we designed this as a drop-in replacement (calling it the Starfruit Actuator). Instead of printing two different plastic joint types, we wanted a single unified metal design to simplify the BOM and actually survive dynamic loads. Specs we're rolling with for the final drop: 30:1 ratio (30 teeth, 31 pins) Dual absolute encoders (supports FOC & MIT modes) Fully ODrive-compatible Target price: ~$149 Next up is integrating the motor and driver board, then throwing it on the test bench to see if it survives a 76 Nm torque test without exploding. Fingers crossed lol. Let me know what you think of the machining! All the STEP files, ROS2 nodes, and configs are going to be 100% open source. I'll drop the project link in the comments if anyone wants to track the testing or grab the files when they go live. submitted by /u/External_Wasabi9131 [link] [Kommentare]
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