awesome. nice design! i'm working on a 1kg barell gear that can output 200Nm with petg cos it's forgiving of printing imprecision. You can use steel tubes inside plastic gears and angle grind a criss cross pattern in them and then use a glue to glue the plastic gears onto the steel tube, the gears need a stellar or internal gear pattern to fuse properly, i dunno what the best glue is.
Here's a cool fact: humanoid robots should do 100ds of different tasks, tea, washing, carrying, tidying... Garden robots just need to do 5 jobs that machines already do, digging, sowing, weeding, cutting etc. sooooo... what is a more useful investment of time? the one that feeds 8 billion people with 50 cents of fruit and veg a day or the one that already has competition? :) hi from the UK.
Well, the BD gave up on hydraulic atlas so you planning on competition with it by proxy now won the contest against electric atlas. im honestly disheartened by their decision due to love of hydraulics and how intricate they are
Neat project, especially for a DIY! Just my two cents, but in my experience with bipedal balancing, it is usually better to model your system as minimally as possible; i.e. model the system as a single mass-body with CoM at a single point (for humans, roughly just above the hips), with the legs as 2-link limbs (2DOF) and the "feet" as single points of contact. The rationale behind this is that, given this simplified physical model, the moment of balance can always be defined about the axis connecting the two feet on the ground (think of a "tightrope"). Firstly, even if your hips have an additional DOF, this will not change, because you are reducing your ground reaction forces to point forces. Once your 4 DOF system can reliably compensate for angular momentum and stay upright within these constraints (a decent challenge), you can use wheels, casters, banana peels, whatever as feet, because the system above the ankles is dynamically balanced. As a side effect, it's also more energy-efficient, because the robot is not constantly working to re-position itself under its center of gravity. Sorry for the unsolicited advice; hope to see you continue working on this.
I am going to take electronic branch in college for degree and i want to make highly efficient humanoid .... And your video gave me relief that we dont have to spend too much money in readymade actuators....😊. It will be very helpful if you given me file ....or something
I love the design and cannot wait to start my own. Have you considered adding a foot that can fold down into place to support the bot while resting, or going up stairs?
I know bldcs have pretty high specs on paper but aren't like BD hydraulic actuators actually a lot stronger in terms of peak usable power? I mean like they make a giant metal robot jump and do cartwheels... Not to throw shade. You are doing awesome work!
Awesome! Can you tell me more about the axial load the actuator can with stand. I'm working on a robot shoulder joint. I'm wondering if the actuator can hold heavy load sideways.
It's been tested with an axial load of a human weighing ~70kg. I reckon it could go higher. Make sure you mount to the outer ring to avoid loading the central surface of the output.
Nice build! I am curious to know how the backlash of motors translate to the foot or ankle. You can lock the rotors and push the ankle to measure. It is okay to have some play tho if you are doing force control. Also, when you do locomotion control, the robot will definitely freak out at one point, and if it hits something hard (like ground), it could break weakest point along the transmission (usually the pinion). Under 1kg is absolutely amazing, but I am curious to know if it would survive real world testing.
Since it's preloaded, there's little to no backlash. Surprisingly there hasn't been an actuator failure in the months of testing. Though it recently snapped its own leg off at the hip during a sim-to-real transfer freak out 😆. Happy holidays!
This design is brilliant. It is clear that a lot of hours have been put in this and i am excited to where this will go.if it scales it will change the world. This could turn robots from a niche only affordable with constant use to a near household product
Hey - I wrote you an email not too long ago... BEAUTIFUL is the word that encapsulates this video!!! Every design choice makes sense, much improvement to be had in the long term but for what it's worth THIS is where robotics meets real life meets youtube meets open source is going ... I'm thinking it will be a while before I get my parts in the mail, til' then though you better look forward to a nice STEAMING hot video on your doorstep involving YOUR actuators! I can't wait to show you my process and what's been going on in my lab! See you then man.
That's really awesome, respect! Why dgm driver? v1.2? It seems to cost almost 40% of the whole actuator. Any ideas how to make it cheaper and still reliable?
Thank you! The cost of dgm controller v2.0 predominantly comes from components like the FETs, gate driver, encoder, and micro. And these are necessary for controlling a BLDC. Good news is that these components are slowing going down in cost.
I have to say I love they way you think. So often people design product with no concern to cost, ease of repair, weight & ease of manufacture etc. I also find that the general approach is to over engineer everything regards of need. This is the polar opposite of what nature actually does. I think the fact that you have made the right and left parts interchangeable is brilliant as keeping the part count is low is super important when manufacturing. I am waiting on a Bambu Lab printer so I can purchase your CAD and start tinkering as I think your product/project has unlimited scope and I have already some idea's on how I can utilise your actuator. I notice that you have an Aussie accent, any chance you are located on the east coast?
The way things are going having a bot that can be trained in simulation and then ported to the real world zero shot is what's next. Real-world data is more important for reinforcement learning though so who ever has the most bots sending back training datasets should have a real advantage as well. Quick and dirty to get the data to scale.
The key frame says "designing plastic to rival steel" - what plastic did you design? Did you invent a new fiber-reinforced resin? Which one is it? A lot of us ME's would love a plastic that rivals steel! Is it glass-filled PEEK or maybe carbon-filled Ultem™?? Come on, we're all dying to know what resin competes favorably with steel! Spit it out!
Subscribed! I've been building my own BLDC motors, axial flux ones. One of their advantages is more efficient use of electromagnetic flux -a lot of the flux in these radial designs seems to go straight out the side of the motor, Hallbach array on the magnetic circumference would probably help concentrate magnetic 'juice' inwards where it can do more work... Looking forward to seeing more of your robot and what it can do!
