Requested — Edited

CAN BUS Control Score 5627

Challenge. Go big or go home.

I'm looking into the CAN actuators used on the Cheetah mini. They are not poorly priced ($300) and offer 150 pound/inch of torque @ 24v. They are brush less, geared and have their own built in drivers, smooth motion and quiet operation. I have an up coming project and would like to control these with EZ Builder. There are arduino shields that support CAN and there is even a pre-written sketch to send data to a CAN actuator. The actuator protocol is somewhat like Dynamixels, in that you can change ID, monitor temperature, control speed, direction and position.

What say you? I'd like to see support added for more industrial actuators like this one, and Servos like ClearPath . Inspiration came from this guy (who cracks me up) and managed to pull this off very quickly using a few of the tools below. Hardware starts at 5:40.

Shield: https://learn.sparkfun.com/tutorials/can-bus-shield-hookup-guide/all Sketch: https://github.com/Seeed-Studio/CAN_BUS_Shield Actuator: Actuator

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#1   — Edited

That'd be easy for anyone who takes this on... Here's how:

  1. modify the existing arduino ezb firmware code and replace the existing servo movement commands with commands to send to these servos

Done. That gives you 24 servos and default ARC 180 degree resolution

----  And your other option, if you want more servos and higher resolution:

  1. modify the existing arduino ezb firmware code to receive a servo id and a 16 bit position
  2. modify the dynamixel skill control to send the commands via UART to the arduino

Done. That gives you 99 servos and what ever resolution you want

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#2  

I figured it would be easier, than say from scratch, since the arduino code was there. Both great options to try. Although the second one seems more intriguing, more actuators and control at 16 bit.

Anyone willing to take a crack at this? Thanks in advance. I've ordered items to test with.

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#3  

To piggy back off this and to stay on topic, head over to this Kickstarter. This company decided to build a robot arm AND designed their own actuator as there is world shortage of harmonic drives. Better yet they are selling these actuators for on $99 each! They have so much going on gravity, object collision etc...run over and see the video..oh did i mention the complete robot arm is only $579? That right! and the 6 axis is a little more. This is using the same controller as shown in the above video and CANBUS.

https://www.kickstarter.com/projects/1383636492/the-smallest-servomotor-robotic-arm

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#4  

It'll be easy to make a control and communicate with the protocols for this stuff. The only thing missing here is the protocol :)

#6  

I love Skyentific!!! :D

Good findings...cannot wait to see your implementation!! When will we get the reveal in whats going on behind the scenes? ;)

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#7  

These canbus motors will be for a project next year, and if implementation happens by someone who writes a control for it...

The project I’m working on now will be showcased on my YouTube channel, set to launch in January. I usually create a robot project here, but I don’t want to spoil the surprise! This robot will cover probably 8 -10 episodes, releasing one 10-15 min video a week.

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Synthiam
#8  

A control merely needs to bind to the OnServoMovement event of the EZB.Servo library and send respective commands to the canbus controller. It'll be easy :). We just need to know what we're sending to the canbus controller to move the servos. That means we need a protocol document. Something that says "send this and a servo will move". If we know that, it's pretty much a copy and paste of the dynamixel skill control from here:  https://github.com/synthiam/Behavior_Control_Dynamixel

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#9  

In the example of the cheetah mini motors listed above ($300)  he used this Ardurino library to control:

https://github.com/Seeed-Studio/CAN_BUS_Shield


The Gluon robotic arm motors are controlled using a small library Skyntific wrote using 11 simple commands seen here: (these motors not available til June 2020) User-inserted image

...from this video :

#10  

Nice find Will. I looked over his Kiskstarter page and was real impressed. That video with Naomi Wu is sure impressive. She really knows how to program and work that arm. Very smooth with hardly any bounce. :p

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#11  

Yeah Naomi is a hoot. And really talented :)

#12  

Hey guys, just in case you are still thinking about implementation of those Cheetah Mini actuators, I found pretty good info on how to use them! :)

https://docs.google.com/document/d/1QIEI6IdHOcW4N1cRyucb33io4LriNYafIMs1sjLfTQU/edit

#13  

SCA QDD Lite-N30 actuators ($89/$99) is also supersweet...plus they offer kind of an all in one package, which is super easy to use!! :)

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#14  

Thanks for the link! These CANBUS actuators are the future for robotics. The compliance portion of the motor will keep robots from hurting humans.

#15  

Yup...pretty good products, been thinking about a bigger humanoid arm lately, its becoming more easy and affordable these days!! :)

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#16   — Edited

You guys have to agree on a specific model and product to use before investing time into creating a skill control for it. Remember, every single one of them use a different protocol - it's like dynamixel times 100. There's all different and use a different language - so once you decide on one, then you can support it. Otherwise, it is impossible to support all of them because there is no standard.

I've repeated that message a few times earlier in this thread. Get the product you want. Make sure it's the right one. Then support can be added for THAT one. It won't work for any other one. Every one you want till require a completely new reinvention of the skill control.

#17   — Edited

Yes, affordability is important but so is availability... No point creating a control for actuators that are difficult to find and/or buy.... I also would definitely be interested in these type of actuators....

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#18  

That's your mission, if you choose to accept it - determine what actuators you wish to use so they can be supported.

#19  

I am completely with you guys.

Lets research...sit down, do our homework and also whoever thinks that a product is good enough to be worth the investment, will need to buy it anyways for further testing! I mean, for an arm that kinda works, you'd need at least four of them!

I just wanted to share what I found, I did not mean to imply that @DJSures will have to make a thousand skill controls for all those different actuators!! :)

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#20   — Edited

The company I originally linked to in this thread with the robot arm must have broken TOS with Kickstarter as they have been taken down. They are in Beijing.

I believe the video I just posted is using those actuators. But how to know if they will be publicly available?! I also like the size.

Aliexpress has a robot parts section. Maybe we start there. I plan on covering this topic on a future episode on YouTube. If for anything the importance of compliance in larger robots.

But price vs strength is the ticket.

#21   — Edited

https://www.aliexpress.com/item/32985671853.html?spm=2114.12010612.8148356.4.3f551b49CcMhSK

They are US $359.00 at Aliexpress ...

edit I thought these were the ones that you meant when you talked about the original post...ups!!

#22  

Hey is also reviewing these ones...they come in two flavors!

US $448.00 https://www.aliexpress.com/item/10000018030781.html

US $379.00 https://www.aliexpress.com/item/10000004036730.html

#23  

INNFOS is no longer available on Kickstarter, but I guess they will be selling the product elsewhere soon?

https://innfos.com/

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#24   — Edited

I’m curious about the Kickstarter. Maybe an investor stepped in to fund them completely.

I did see those other actuators reviewed on skytenifics channel. They are very pricey and physically bigger than Innfos, but I bet considerably stronger.

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#25   — Edited

Given that innfos website is all rendered images (not real photos) and using stock photo clip art of a robot AND their banner ad is promoting stuff from last year AND the news page is broken AND AND AND AND.... I'd have to say they're no longer in business guys - move on to a real product.

Half their website doesn't work. Geez, i hope you guys do better due-diligence before purchasing stuff online than this:) You're gonna go broke buying vaporware!

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#26  

Ummmm please watch the video I posted on #14. That is not computer generated.

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#27   — Edited

Right - there's a few things but I'm guessing prototype. The company went kickstarter to try and recover from a financial crisis, I imagine. Companies that receive investment and thrive make money from sales - and sales requires a website.... something they don't quite have ;). Due to the price and promise, we wish they existed but my gut says no more

Also - china is a weird place for business because one business can have 10+ operating names. So that business could be a sub of another business which is sub of another that's no longer operational. Or, it was assembled as a concept to gain traction... the traction never happened so poof it's gone and the owners are onto something new.

Either way - a business that doesn't sell anything or makes it difficult to buy anything or use their product... isn't really a business :D

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#28  

Totally agree. I'm sure their business plan (if they have one) has changed 100 times. How many times do we say if its too good to be true, it probably is. The price point on those motors was really low. My guess is someone like softbank is backing them into making robots instead of robots actuators for the general masses. Either way...we can X them off the list!

#29  

The actuators are real...but only time will tell, if this is just vaporware or a real product!!

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Synthiam
#30   — Edited

One way to find out - maybe they can be saved if there's customers. Send them a message on their website and see if there's a response. They do have quite a bit of info in their wiki so hopefully the products exist and are available for purchase

#31  

Well probably not... Someone "raided" the office, maybe it was a bullied robot? :D

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#32  

WOW! Thats a bunch of pissed off investors

#33  

Just in case someone might find this helpful...  There is a link for a tool to calculate servo motor requirements, as for bigger projects it might be good to just kind of eyeball the right components before investing in the actual hardware! :)

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#34   — Edited

I don't think these controls are needed anymore (CANBUS).

There are many companies coming out with different motors that run on 3 phase like the hoverboard motors. An example is the 9225-90KV Multistar brushless outrunner by Turnigy.  James Bruton is using these for another one of his robot dogs. And they are 1/2 the cost (or cheaper) than the Canbus motors and very very powerful, when running at full capacity (48 v). They are also much lighter than hoverboard motors. They have no gearing they are therefore back drivable and compliant. The motors can be used with the same Flipsky FSESC 4.12 50A Based on VESC (Motor control interface: PPM signal (RC servo), analog, UART, I2C, USB or CANbus. ) controllers that I use in my hoverboard hack video.

Mind you these axis would be for large robots. So you bet I have a project with these in mind!

Definitely will see these in an upcoming video.

Mind you you would still have to add an encoder so the motor would not rotate non stop.

#35   — Edited

Hey, lets keep this thread alive for different ideas on heavy actuators...

I am also currently looking into cheap ways to get a bigger robot arm working!

I was leaning towards a 3d printed cycloidal gearbox, since the reduction ratio vs gearbox size is tempting and it is easy to print, while a harmonic drive is kind of impossible to 3d print!

I was thinking to start with standard Nema 17 stepper motors first and then switch to brushless motors and encoders?

But all of this is new to me, and just a fun thing to try...so lets pool ideas? :)

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#36   — Edited

I'm really interested in seeing how James will incorporate the hall effects sensor on these motors for tuning position. The motors are designed for drones, so they are meant to be spun up at high speeds, not positional. Looking for torque and holding power on these when connected to the ODrive.

Yeah looking forward to discovering all the emerging new motors.

#37  

I will try to find out, how he is getting it done...but yes, those drone motors are nice, because they are pancake style and offer a lot of torque while consuming little space, and it is very easy to put a strong reducer on top!! :D

But getting those encoders and ODrive, or another system working will be a fun thing to play with!!

Also the Wattage, plus counting the power consumption at startup is essential!

The more I get into this, the more I realize how complicated it is... Which is a good thing!! :D

#38   — Edited

Hey, I just ordered an ODrive and some Tarot 4008 motors...

It will take a while for all the stuff to arrive, but it should be a lot of fun to play with! :)

The ODrive can handle two DC Motors, plus Encoders and Gear Boxes are needed, which adds up to the cost of those relatively cheap motors...

I got the encoders directly from Odrive, and I guess there could be cheaper options available...

Also hopefully I will be able to 3d print my gearbox to save some total cost!

At the moment the cost is about 100$ per joint, which would be 600$ for a 6DOF robotic arm...

This is all WIP and testing stuff, I might open a seperate thread on this, once all the items are shipped!!

Anyone also interested in building a silghtly bigger robot arm?

Could be really cool in tandem with ARCs Exosphere!! :D