@harrisonlow 4 ай бұрын
Just realised for around 20:00 it's relevant to note that I'm using UHMWPE (dyneema) thread, which (AFAIK) doesn't stretch *too* much, but obviously seems to at least a little...
@wolpumba4099 4 ай бұрын
*Abstract* This video details the progress and challenges encountered in Project DeepBlue JuggleBot, a juggling robot project. The main focus is on the catching mechanism, with recent tests revealing excessive inertia causing the ball to bounce off the hand. The video explores potential solutions, including using smaller motors and a bidirectional drive system, and discusses the possibility of incorporating ball tracking and D3O impact-absorbing material in future iterations. *Summary:* *Housekeeping (**0:00**)* * A simple fix for overly tight XT60 connectors was discovered. *What Went Wrong? (**1:53**)* * A ground connection issue caused damage to several CAN transceivers. * The extent of the damage is still being assessed. * ODrive Pro might be more robust against this type of issue. *What's the Damage? (**4:40**)* * At least one ODrive and the TNC transceiver board are fried. * Replacing the CAN transceiver chip on the ODrives might be possible. * Thankfully, the Jetson computer is undamaged. *How To Stop this Happening Again? (**7:00**)* * Using bus bars and soldering directly onto the ODrives are potential solutions for preventing loose connections. *ODrive (and motor) Delivery! (**12:24**)* * New ODrive Pros and small, powerful drone motors have arrived. * A decision needs to be made whether to switch to the new ODrives or attempt to repair the old ones. * Gearing the new motors down might be necessary, but could increase inertia. *A Question About BLDC Motors (**15:14**)* * Can the new motors be safely powered by a 45V power supply despite being rated for 22V? * Overpowering might increase speed and heat, but the ODrive can regulate speed. *Progress on Catching (**17:03**)* * Catching tests have been conducted with a compliant hand design. * The hand throws the ball very high, potentially hitting the roof. * An unexpected problem arose where the strings pop off the pulley during fast movements. * A solution involving a tapered ceiling above the pulley might be implemented. *Thoughts on Inertia (**33:01**)* * The current setup has too much inertia, causing the ball to bounce off the hand. * A test rig will be built to investigate the relationship between ball and hand inertia. * Smaller motors with low inertia are promising, but gearing them down could negate this advantage. *Brief Tangent on Ball Tracking (**36:48**)* * Ball tracking is planned for future iterations, potentially using a 3D camera or a laser gate. * However, open-loop control might be sufficient if the robot is precise enough. *Returning to Inertia (**39:02**)* * Gearing down motors increases their effective inertia. * A test rig with different gear ratios will be used to assess the impact on catching performance. *BLDC Thoughts (**42:49**)* * BLDC motors are not significantly affected by voltage, but heat could be an issue. * The hand motor's duty cycle will be low, potentially mitigating heat concerns. *Pre-empting the Ball While Catching (**45:30**)* * Pre-emptively moving the hand to receive the ball could reduce the required motor force. * This has been tested, but the current setup's inertia still causes bouncing. *Thoughts on the Constant Force Springs (**48:08**)* * The constant force springs might be replaced with a bidirectional drive system due to reliability issues. * This would require careful string routing and potentially another fuse to prevent the hand from hitting the base. *D3O (**53:02**)* * D3O, an impact-absorbing material, might be used to line the hand and reduce bouncing. *No Stream Next Week (**53:59**)* * There will be no livestream next week due to the Easter holiday. disclaimer: i used gemini 1.5 pro to summarize the youtube transcript.
@darkmann12 4 ай бұрын
41:10 ish - yeah this is a thing I also don't love about the larger (of the smaller) drone motors like that (yes! they get SO much smaller!)- but because the propellers are so light, they don't have lots of rotational inertia, so the likelihood of them slipping is very low. Moreover - plenty of motors with that propeller mounting standard do have teeth cut into the base where the propeller sits, so when you cinch down with a locknut, it digs into the prop some and provides some mechanical keying
@harrisonlow 4 ай бұрын
Yeah these motors have very slight features that would achieve the effect you're describing, but it definitely doesn't seem super solid. I was recently talking with a friend about this and we came up with a potentially good solution: the part that's mounted to the output shaft can have a cutout to fit the locknut, so that when the nut is tightened, it both clamps the mounted part as well as preventing it from slipping, since the nut fits snugly in the mounted part. A little tricky to describe with words, but I think it should work well!
@davidt2044 4 ай бұрын
You mentioned removing the CAN transceiver chips from one board to acquire replacements. I'd recommend against this as removing them is a big hassle without a rework station and even with one or sucks. If you order naked chips you can destructively remove the broken ones and save a ton of headache
@harrisonlow 4 ай бұрын
I hadn't thought about this, but you're absolutely right. I'll order some plain chips right away! Cheers 😊
@harrisonlow 4 ай бұрын
I just resoldered one of the CAN chips and my goodness am I thankful for your suggestion here! Even with the plain chip, the soldering was very tricky to do; I can't imagine how much harder it would've been to remove the old chip in a non-destructive way. Big thanks for this suggestion 😊
@planckstudios 4 ай бұрын
The density of your ball is so different from the ball bearing they dropped on the D30. Doubt it will provide the solution you want. I think, given all the articulation you've created, it's mostly software to track the ball and move the catching mechanism to gently receive it. This could also serve as a sort of closed loop system where unseen variables altering the ball's speed/position/trajectory would be addressed by tracking the actual ball
@harrisonlow 4 ай бұрын
That's a very good point; the elasticity of Jugglebot's balls would definitely affect the ball > D3O interaction. I agree that software can go a long way towards making this system work, but part of me feels that there's some (relatively) simple way to improve the hardware to reduce software complexity by quite a lot. It's just a matter of finding what that improvement is 🤔