ROBOTICS | Backdrivability and speed test of Harmonic Drive-based robotic actuator 

Yes, definitely! Check these publications: www.researchgate.net/publication/233703891_Investigation_and_strategies_for_precision_of_miniaturized_robots_with_micro_gears and www.researchgate.net/figure/Micro-Harmonic-Drive-gear-train-made-by-Micromotion-GmbH-Mainz-Germany_fig5_225550342

A distribution of Facebook reality labs is working on prosthetics I don't have a link sorry as much as I dislike Facebook they are pushing this technology further than it's ever gone I wish you luck and hope this industry grows even more

I hope we get to know some insight of what controller and programs your using !

@@shashankshekhar6549 Thank you! Sure, here is the controller: tinymovr.com/

@@OleksandrStepanenko ooh!! those are really good. Performance at an affordable price.

Then I'll try to justify your feelings 😉

I'm building a scara bot arm as a hobby project at the moment, my initial design uses planetary gearboxes to get the most out of the small 200W ac servos chosen. I have been looking at harmonic drives recently because of the much better backlash. At J1 the gross mass is around 16kg. Would you recommend sticking with planetary in this case or going with a fairly large harmonic drive (looking at 60Nm average peak load for the speeds I'm aiming for)?

Thank you for this information. I'm a robotics hobbyist and the professional experience is appreciated. I would like clarification on one point: when you say that small harmonic drives tend to slip and get damaged in high-torque applications, does this not assume that the harmonic drive is non-backdrivable (or perhaps is backdrivable but can't handle shock)? I thought professional-grade harmonic drives were common in stationary robotic arms used in assembly lines that cannot be backdriven, and thus enjoy high accuracy at high speeds, plus the motor controller can (mostly) be pre-programmed for specific paths. The torque-damage threshold of a small harmonic drive can be increased by combining it with a planetary gear setup. Extreme-torque applications should have a separate braking system that automatically engages if the robot loses power. Comparing pictures of industrial 6-axis/7-axis robot arms lifting welding guns vs. lifting cars: the motors look identical but are different sizes and are connected to different gear setups, and braking mechanisms look different and may or may not be present (I acknowledge I'm a layperson and pictures can be deceiving). Cycloidal drives are preferable for mobile robots, where the backdrivability allows the motor controls to compensate for unpredictable torque requirements caused by uneven terrain. This video shows what appears to be a reliably backdrivable harmonic drive with 50:1 gear reduction. If performance and cost are competitive against cycloidal drives, this harmonic drive may be viable for mobile robots, or for assembly line applications on SCARA or 6-axis/7-axis robot arms that feel mild shock. Presumption: if a mobile robot jumps from a high ledge, the torque will be severe upon landing. This 50:1 backdrivable harmonic actuator will transfer this burden to the motor in a fraction of a second, during which time the strain-wave gear teeth will experience severe stress. Cycloidal drive trains are inherently good at handling this shock, harmonic drives are not. Having said that, the robotics on Mr. Stepanenko's channel are exceptional quality, so I'm inclined to think this harmonic actuator may be useful under certain conditions.

Yes!

Well noticed!

@@OleksandrStepanenko Robotics & Image Processing my main hobbies :)

Thank you!

Thanks! www.harmonicdrive.net/

Thank you!

Thank you, Ali. It's quite expensive indeed. I think it would not be ethical to discuss the cost... Try to request Harmonic Drive directly, I'm sure, they will answer.

Thank you, appreciate your comment! Yes, I use Logic Pro. You can also try GarageBand, it's free and pretty good as well.

Thank you!

Thanks! I don't sell it at the moment, but you can check out the actuators from Harmonic Drive: www.harmonicdrive.net/products/rotary-actuators

Thanks! At the moment I have only tested the precision: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-r5FCMSFGZQs.html

Thank you! I will show it in the next videos.

Thanks!

With a 50:1 ratio no less!

Harmonics below a certain ratio are backdriveable. A force applied to the output will cause the flexspline to deform in a way that exerts a rotation on the wave generator.

It's mechanically backdrivable with the motor off.

Otherwise, many Industrial robots would break into pieces if there were a power outage. The strain wave is backdriveable, and the power-off brake needs to have a dynamic braking specification.

Just as described in Spaceballs: we have to a low down first. m.ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-ygE01sOhzz0.html

Sure, www.omc-stepperonline.com/nema-11-bipolar-1-8deg-12ncm-17oz-in-0-67a-6-2v-28x28x51mm-4-wires.html

Hello is it the motor you used in this video? I thought it was bldc

About 100 euros per motor (check maxon online shop)

Sure tinymovr.com

www.thorlabs.com

tinymovr.com

bldc flat motor

What is the model you used? Can you give the link?

yes please 🙏

tinymovr.com

tinymovr.com

Yes, definitely!

Sure, this is in my plans 😎

I mean like, instead of controller -> robot, go robot > controller and read the values etc

@@eurybaric Exactly. I can teach a position by simply moving it manually.

@@OleksandrStepanenko That's amazing! I'm not in the field in any way, but i'm imagining you would teach it a sequence, then clean it it up in software, yeah? And follow up, what's the resolution on something like that (distance and time)? In any case, awesome stuff :)

I don't sell it at the moment, but you can check out the actuators from Harmonic Drive: www.harmonicdrive.net/products/rotary-actuators

I agree, audio is not the best here...

No way 😮