Reddit mentions: The best permanent magnet motors

Very cool idea and I hope you can make it work. Seriously. Keep going, and don't give up. It's probably going to take you a full year to build something like this, but the world needs more people building these types of robots.

So, you're going to need a ton of power to do something like that. 9 kg payload for a shoulder tilt joint controlling a 1m long arm requires ~100 N-m of torque w/ about 60 RPM to match human speed. The most powerful servos that I've ever seen can only match about 1/10 of the torque requirements: https://www.servocity.com/servos/hitec-servos#large

You're probably going to need to do something like a 90V power source and get motors like this bad boy: https://www.amazon.com/MOTOR-1800RPM-90VDC-TEFC-FOOT/dp/B007L7UAXM. Geared down, it could output 200+ N-m of torque and at $200, it's much cheaper than a servo would be. It's also huge and super, super heavy, but you get the idea. There are a lot more 90V motors that meet your requirements.

Since this isn't something that people generally build, you're going to have to hack together a design using off the shelf components that aren't traditionally designed for robotics. But it's possible. You just have to be industrious and figure it out.

Upvoted because these are the things that make up the ideal BEV.

>I only want everything

Low cost, High range, Fast recharging, and Good performance are the zenith of EVs.

I know mostly about the LEAF, which seems to relate to lots of what you're saying. But some of your claims are incorrect, and others are mutually exclusive or misguided.

A car optimized for range will have reduced torque, thus no need for 4 motors.

A cost-focused EV wont have the tech to control the car's dynamics or the need for 4 motors.

Therefore, if we're prioritizing cost, it'll be 2wd via single motor and transaxle rather than hub motors.

Regen-only braking would be out of the questions, since the motor's only connected to 2 of the 4 wheels, so add discs or drums to the other two.

3D Printing in the manufacturing world is generally called Rapid Prototyping because it brings benefits to producing a part that is more efficient than creating tooling for a specific part, only to have to change it for the next part. What 3D Printing is not as good at, is mass-production. Once the part is ready for prime time, and you need thousands of them, other manufacturing methods will leave 3D Printing in the dust.

I had to save this one for near the end.

Wiring a the battery's cells in series rather than parallel means that when you have the two main leads connect to your motor, i'll look like this 7.4v DC motor, assuming you're using the cells that Nissan makes, or you could go with the cells that Tesla makes and get a handful (approx 7000) of 18650 Panasonic batteries and only need an electric motor like this one.

A couple of other points:

LEAF 0-60 is under 10s, with extra efforts going into reducing torque to prioritize range.

The Eliica's battery is lithium-ion, just like many EVs on the road today. It weighs as much as the original Humvee in order to get that range with that power.

Interestingly enough, I just pulled a failed Li-Ion battery from a small R/C plane that would be just about the right size for a rodent car. Image

So that's a 3.7 volt battery with a capacity of 250 milli-amp hours. We can fudge this number and say between both a slightly larger pack and advanced miniaturization, they use a 400mAh battery in a theoretical rodent-sized vehicle.

Now our drivetrain- A cellphone vibrator motor is about the size of motor you'd be able to use. It'd have to be a single motor with a gearbox driving the two front wheels, most likely, as I can't imagine managing to build a multi-motor drivetrain that's not going to fry your battery and they really don't need all wheel drive in Little Rodentia anyways.

So as we can see, that motor there uses 3v at 0.2 amps (200mA). With a good gearbox reduction, probably should be enough power to accelerate a vehicle that weighs less than 300 grams at a decent clip. But that's getting into a ton of force calculations that I reallllllllly don't want to do at the moment.

ANNNYWAY- we never want to draw 100% of our battery's capacity, because not only is the last 15% not usable due to low voltage, it's bad for the battery's longevity and a good way to overheat it and cause a short, leading to fires and death. Not good. So we should use, say, a 25% capacity buffer (Li-Ion should handle a 75% depth-of-discharge easily enough), so our 400mAh battery now becomes a 300mAh battery. Alright. That's how much energy we have available to us. Tack on a few milliamps for accessories and lighting, plus 5% conversion and discharge inefficiencies, and say there's about 280mAh available to the motor.

At "full" load, the motor should use 200 milliamps. In practice, it's going to use much more when accelerating (probably close to 275mA) and much less while cruising (maybe 100mA or so.) But as a running average, let's just call it a day and say the damn motor uses 200mA during normal driving. Yes, I'm a lazy engineer, so sue me.

That means the motor should be able to run for about an an hour and 24 minutes continuously. Again, fudge a safety factor in for heavy acceleration in city driving and other inefficiencies in the gearbox and wind resistance and other shit that I haven't totally accounted for, and let's just say you can get an hour of safe runtime out of your little electric rodent car. Sounds pretty good, yea?

Now, let's convert that to actual range. Let's pull some more numbers out of my ass, and say the tires on this car are 1cm in diameter. That's a circumference of 3.14cm, so the car can travel 3.14cm per rotation of the tire. The motor I linked has a free-speed of 1100rpm, but with a load on it (assuming the final gearbox stage is 1:1) it'll probably be closer to 1,000rpm. 3.14 time 1000 is 3,140cm per minute, or 28 meters per minute. In conventional terms, that's 1.88kph or 1.1mph. Being able to run the motor for about an hour means our equivelant range is also 1.88km or 1.1mi. That's probably not too bad in Little Rodentia, but for getting anywhere else that's a bloody slow ride to get not very far. And if you look at the scenes where we see rodent cars, both in LR and driving along the street where Nick is walking, 1.8kph probably isn't too far off from an average speed.

With this information, it's probably safe to say that there's no "one-car fits all" in Little Rodentia. our little theoretical car here would work just fine in LR which probably isn't even half a kilometer in it's longest dimension, but you'd need a different, much faster car for driving anywhere outside of LR. This makes the subway and/or pneumatic tube idea much more palatable for long distance transportation, since they can just zip along a nice, sealed tube at 40mph and be on the other side of the city in less than half an hour.
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...Good lord that comment turned into a monster. Then again, I just got a new keyboard and love typing on it, so maybe that contributed to it's length... lol. I'm gonna go clean the house now.

Something that might find handy to experment with. Your basic two wire motor can act like a genorator. Get a hobby motor of some kind perferbly with a gear on its out out shaft. An old cheap toy car motor works great for this.

Ex: https://www.amazon.com/Karlsson-Robotics-CECOMINOD023557-Hobby-Motor/dp/B00O46HNUG

If the wires are not hooked to anything you spin the end very easly. There is othing taking up the power you are genorating. It like a fan just sitting on your desk. Now try this, connect the two wire together. When you try to spin the end it will not spin that easy if at all. Shorting the wires simulates a very heavy electical load that the motor is trying to power. If you have access to some flash light bulbs or leds you can try powering them from the motor. The more you try to power the harder it is the spin the end of that motor.

How this applies to question of why your can't put a generator on your bike tire and get an more range it is because while you may be able to spin the generator freely with out a load when you put a load on it, it will have resistance. A bike light with modern LEDs would put a smaller amount of resitance you might barely notice it. A generator of useful size would cause a substantual resistance.

We can make use of the resistance though in regenertive braking. Instead of using the friction of brake pads as resistance we use the electical load of charging the battery back a small amout to slow down.

I've already sold the Pixhawk on RCGroups a month or so ago.


Saving up for the WKM and repairs (getting retracs this time). So all in all its gonna cost at least $1200 to get her up and running. Props don't come cheap either and you've gotta have multiple sets when you're out on a shoot.

For batteries, I'm currently using two 6s 8000mah turnigys in parallel. I mentioned before that it was too light so I may have to bump it up to two 16000 or something similar (very expensive-hindsight when starting).

That's an interesting solution although you would need a really big generator. For my rig, which has 6 motors pulling close to 800 Watts each at max throttle, that's 4.8kW you'll need to generate. Approximately, you'll be needing a 5 horsepower motor. Which isn't going to be light. Very interesting thought though and gave me the realization that it's not feasible at the current state of power generation. Something like that would need significant DC stepdown as they're probably going to be 180V like this one. AC motor then stepdown would be the way to go if its a really big rig with efficient pancake motors and props. Stepping down that much current in DC is highly ill-advised. Maybe this along with a 24V transformer would work.

Here you goI'd still recommend ordering from the main site, they may have important information that's not detailed or is better formatted on their own site.

Hold on to the Nextrox motors, they could still be useful for lifting.

The motor I got out of the printer was a brushed DC motor, and I ended up replacing it in the build you see above. Here is the motor I used from Amazon, it's a brushed 12 V DC motor. This motor is super torquey and has some really good speed to it

At its simplest all you need is a motor with something lopsided on the shaft, which you could theoretically build from scratch. However there are some good quality low cost ones on amazon for a few USD under the uxcell brand, which I have had good experiences with (but with other products). Like this for example.

What are the dimensions of the space inside the steering wheel?

https://www.amazon.com/uxcell-3100RPM-Vibrating-Vibration-Massage/dp/B00AKWRWRW/ref=sr_1_7?ie=UTF8&qid=1478586664&sr=8-7&keywords=vibration+motor

https://www.amazon.com/1-5-6V-50000RPM-Coreless-Vibration-Motor/dp/B00QC2F4FQ/ref=sr_1_5?ie=UTF8&qid=1478586664&sr=8-5&keywords=vibration+motor

https://www.amazon.com/1100RPM-0-2A-Speed-Vibration-Motor/dp/B0087Y95X4/ref=sr_1_3?ie=UTF8&qid=1478586664&sr=8-3&keywords=vibration+motor

but also if you can't find something small enough to fit into the compartment and powerful enough to shake the wheel you should consider putting several of the phone vibrators in parallel around the steering wheel itself.

Thanks for your help, I have another option that opened up to me: single phase 120v dc controller with variable controller. I need some sort of digital controller because I'm limited by the lathe house as to how much I can reduce the speed via pulley sizes. Take a look at these and let me know your thoughts:

KBIC-240D - http://www.galco.com/buy/KB-Electronics/KBIC-240D?source=googleshopping&gclid=CMSovIPOq9ACFZSHaQodumkG9g

Motor - https://www.amazon.com/gp/product/B007L7UAXM/ref=ox_sc_act_title_2?ie=UTF8&psc=1&smid=A22TWTERVPMK3W

w/ controller knob:
http://www.ebay.com/itm/New-KB-Electronics-DC-Motor-Control-KBMD-240D-9370/301901808903?_trksid=p2047675.c100005.m1851&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D39107%26meid%3D7db6513f5caf4b99875761b549fae719%26pid%3D100005%26rk%3D1%26rkt%3D6%26sd%3D160482724113&rt=nc

alternative:
http://www.ebay.com/itm/KB-ELECTRONICS-KBPI-240D-DC-DRIVE-CONTROLLER-Tested/231876208336?_trksid=p2047675.c100009.m1982&_trkparms=aid%3D888007%26algo%3DDISC.MBE%26ao%3D1%26asc%3D39107%26meid%3Dd08792902d194ea997da79c30998f798%26pid%3D100009%26rk%3D1%26rkt%3D1%26sd%3D301901808903

https://www.amazon.com/Torque-3000RPM-Permanent-Magnet-6000RPM/dp/B0787WG9QB/ref=asc_df_B0787WG9QB/?tag=hyprod-20&linkCode=df0&hvadid=242041198988&hvpos=1o2&hvnetw=g&hvrand=13048942433025564143&hvpone=&hvptwo=&hvqmt=&hvdev=m&hvdvcmdl=&hvlocint=&hvlocphy=9006807&hvtargid=aud-643191255296:pla-532195958099&psc=1

I think a DC motor would be easiest for this. If you can manage to get a 600:1 gear ratio (which is most easily done with a worm gear on a normal spur gear) the 24V motor should be able to give you more than enough torque. As for speed adjustment you would just have to build a simple DC speed controller for it

Got it.

So, your specification of 30 Hz is (as noted) 1,800 rpm which as it happens is about the same speed as most computer case fans, such as this one.

If you need something a bit beefier you could enclose a motor like this one inside some sort of base, then run the shaft directly up to the base of your frame.

Do you have any sketches?

Also, don't mix too much hardener...if it's a 2 part resin, one part is the hardener...if you use too much, what happens is the mixture gets too hot and contracts which causes pitting/bubbles. This was the case when using Fiberglass Resin when I was making custom dashboards and trunk layouts for show cars. Use a little less than recommended, you'd be surprised. Keep it just a hair cool so it doesn't harden as quickly...also the vibrator motor idea as /u/akelis mentioned is smart as hell. Use a pager motor if you can, like this one here.

I’m looking at Chancs Motors. They claim continuous running from 5-7 hours. Speeds a bit higher, it not a big issue for the purpose. Any idea on their quality?

CHANCS TYZ 60K Synchronous Motor AC 110-130V 20/24r/min CW/CCW Control 14W

https://www.amazon.com/dp/B0144BG61M/ref=cm_sw_r_cp_tai_69gTCbN9BB4NK

Thanks

Hope this helps
2 12V Photoelectric relays
12V motor
6mm bore pully to match motor shaft
Project box
2 limit switches
Solar panel
Battery
If not solar powered. Aka no solar panel or battery

If you have any other questions let me know I am at work and I will answer what I can on my phone

Edit: I forgot a pully to run the rope from, but the motor I linked has so much torque you could go direct no problem, and lumbar to build the door. I estimated about 10$ for wood. I used all treated, as that's what I had laying around, but its probably not necessary as most of the door on my design was in the coop. I can make you a wiring diagram as well if you are interested. That reminds me you should use 4 zener diodes (just because you only need 4 doesn't mean you shouldn buy a 100 for future projects :) also if you goto an electronics store you will pay 5-6$ for 6 diodes) to stop flash back through the whole circuit from the reversing of polarity with the motor.

1 of those: https://www.amazon.com/DC-Motor-Pack-of-10/dp/B00M4L12RS

i have about 6-7 volts

Mophorn 1800W Electric Brushless... https://www.amazon.com/dp/B07KF8M5W6?ref=ppx_pop_mob_ap_share

This is the exact setup. What do you mean by driver?

https://www.amazon.com/Smith-GF2024-Sleeve-Bearing-Blower/dp/B006P1RUOM

I was going to do that and use a combination of a rheostat and some reduction pulleys. I have some other projects that require really slow speeds.