Build a Robot with Windshield Wiper Motors
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- Опубликовано: 24 ноя 2017
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Drivetrain with Washing Machine Motors:
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The Post Apocalyptic Inventor Thanks again for the vid.me updates. I am not at all into FB particularly after thier social experiments, etc. It just becomes to much of a time waster as well.
Alternate drives. So for example on a remote, switch 1 has conventional car steering, switch 2 has dual steering, switch 3 has that weird combination of two found in some cars where the front wheels are controlled by you, and the rear two are automatically turned to a degree to lessen the turn effort, switch 4 custom individual wheel turning.
About the last one, it might seem a complicated mess to put each wheel where it is needed, but, i have seen crawler rigs with such setups in the past. Quite effective when one wheel is lost in space and you want to anticipate a contact.
For your DRILL PRESS, i did the same booboo like you, and fixed it easily doing this:
Mount your lathe, doesn't need to be precise for this.
Mount the appropriately sized cutter inside your chuck, remove everything off the saddle, that relates to the tool post.
Mount a square plate (doesn't need to be precise, i was desperate to finish, did it all in 3 hours including running to the local machine shop supplier to buy new rod), and on it, mount a new piece of rod that fits your dimensions. THEN, using the saddle, run the cutter slowly at the highest speed (i'm assuming a small lathe like yours isn't too fast, mine wasn't when i had one) cutting away the new keyway.
Round the old key's edges, make it smooth. Make sure it fits nicely but without binding, what likely happened to you is, there was something in the key way and the the action rose the key thus chipping and snapping the whole deal.
Seriously, that's a thing you can do in your home with what you have now.
Also, wanted to say, don't give up. A lot of us appreciate the work you do, immensely.
The Post Apocalyptic Inventor The choice of motors is very smart. Thy are small, powerfull, waterproof and should'nt be much used since their function was to remove the water whenever it rains and not all the time. I guess that the inverting switches you diconnected at 1:55 could also be used as crude turns counters in projects where you don't need such a fine angular precision in your feedback control.
Your modular conception (same design for each wheel) is also a great idea. It simplifies both the design the construction process and the programmation. It also makes to frame structure extremely symetrical, which is usefull for simplifying the AI decisions of an autonomous robot.
Great job.
Bei 00:30: B1, kurz vor Horn Bad-Meinberg?
All Good !! . . . . .(1) You continue to excel at VERY clearly explaining complicated topics (2) Seems you are getting caught up and finding your old good rhythm after a very difficult and long transition from the old shop to the new shop in a new location (3) video flow/organization you describe feels very good to me ( get my attention, explain the tech details , finish with some background/related material ) . . I reminds me a little bit of the way to do 'public speaking =>> a:: tell them what your going to tell them // b:: tell them // c:: tell them what you told them . (4) Your apparent recovery from the difficult move is very inspiring to me because I have been going through a one year+, BIG move of house/very-large-shop/tons-stuff and it feels/felt overwhelming, but I am getting back my balance as you seem to be getting back yours. . . . THANKS for what you do!
I am in the same situation as you are. New shop, winter, uninsulated, unheated, no benches. I appreciate what you are doing with what you have. I will become a patreon as soon as I can!
Great job! May I suggest building a wiring rig from the ceiling of your workshop, with the wiring fed through a long extended spring, to allow top down attachment to your test devices, and reducing the trip/obstruction hazard. You could possibly even add connectors at the end of the wires. Maybe 10 lines?
One thing to consider, and is important, in the future, is to install an electrical emergency disconnect pull out plug that disconnects all power from the source. It must be real easy to get to in the event the bot decides to go nuts.
I have already got a wiper motor and plan to get more. I did not consider that brush to ground issue, glad you brought it up. I plan to use the motors for general purpose small motors. The only choice is stepper or dc automotive types. The only type ac induction motors available in USA, and likely the world, are FAN DUTY motors. Those are wound with too small of diameter wire so the motor will burn up if it is not used as a fan. There are a few non fan motors available, but they are more expensive than far larger motors. Near the end of the video the Thing you have looks like it is powered by a small ac motor, maybe 1/10 hp. It looks old. Many years ago, small general purpose ac induction motors were common and cheap, but no longer.
You are the BEST!
Not only are you creative you have a very professional teaching style that is like a Professor you allways wished you had!
optic encoders might get problems with dirt. So I would recommend an enclosed encoder or magnetic encoder like the AS5047. I have made really good experience with the latter.
Great presentation. Thanks. I just wanted to mention that the main reason that the wiper motors are grounded to their cases is for RF interference suppression on a vehicle. Not a problem in your application of course unless you're trying to listen to your on board radio.
you might want to consider using potentiometers for steering positional information. You can tell where each is at any time, with an encoder you dont know where you are on power up
Maybe as an addition, potentiometers aren't known for their stable readouts.
@@MsSomeonenew Potentiometers can be very dependable but it requires attention to detail. Typically, you want zero current in the wiper, ie. an “electrometer” buffer right at the potentiometer. These days it’s easy since you have tiny FET op-amps that can be mounted directly on the potentiometer and only need a bypass capacitor to operate in the buffer configuration. Otherwise, you need a shielded wiper connection to a remote amplifier, and the shield has to be bootstrapped, ie. the output of the amplifier has to drive the shield, to cancel out the cable capacitance - but that’s less preferable than a buffer right at the potentiometer.
Potentiometers interfaced that way will provide very clean signals even if they are very scratchy in terms of wiper impedance. Why? Because there is “no” current flow in the wiper and thus wiper impedance doesn’t affect the potential. When things are clean enough, even complete disconnection of the wiper from the track provides enough capacitive coupling to maintain reasonable output while the wiper regains contact. And that’s the secret to using potentiometers as dependable position sensors. They only fail when the resistive track gets physically worn out enough that the wiper is riding on the substrate. That is remedied by using potentiometers that have specified rotational life and it’s adequate for the application.
Cable potentiometer transducers are commonly used in aerospace applications, after all, so it’s not unthinkable that if you flied enough, your safety depended on the performance of one or more such transducers.
Also, reliability requires that potentiometers used as input controls should not be used to directly divide any AC signals, ie. if you want a scratch-free volume potentiometer then you can’t be passing audio signal through it, but instead using its “DC” voltage output to control a variable gain circuit element (or software). The reason? High impedance wiper interface has low bandwidth. At higher audio frequencies there is enough stray capacitance to “expose” the wiper impedance changes, and re-introduce scratching in the audio output. So, passing audio or any such signal through a potentiometer makes the application inherently orders of magnitude more sensitive to wiper resistance changes and thus scratching. Sure, it’s an “easy” way to get a volume control implemented, but you get poor performance out of it - according to the low effort put into the design.
Voltage controlled gain stages are not too hard to design, since it’s rarely needed for the gain control to be highly linear, only the audio signal path has to have high linearity. They don’t have to be perfect multipliers.
The four wheel steering would make it a great platform for a drawing robot. Make some streetart.
That sure is a long complex list of work to take on.........but that's why I am a subscriber and supporter of TPAI! If anyone can do it you can.
That would make a perfect stand for a steerable drillpress wich you could drive outside automatically in order to work in the sunshine ;) As always very nice work!
As always, interesting and educational! Keep up the great work.
Probably one of my favorite videos so far. You're beginning to put all of the skills you've showed in other videos into one project. Keep up the great work. If it was easy everyone would be doing it.
Love it! I've been heading down a very similar road but your steering mechanism is much better. And I really like that you have the axles supported to reduce strain on the bearings. Nice work!
On the beginnings of the robot, I really liked the music on the intro.
You could spare yourself a headache by using absolute encoder discs for the steering wheels, but you need more light sensors. And have doubt about the durability of the wormweels. But I must say this is an amazing project that has a lot of potential for future projects, very nice! I watch all of your videos
Am I right in the assumption that I need to remove the ground if I want to run it forwards and backwards? If it goes backwards it will fry my Arduino right? Because suddenly the ground would be positive right?
Intriguing intro clips! Hope the damage to the drill-press isn't terminal and getting the lathe up and running goes smoothly!
I remember a documentary showing german soldiers during WWII controlling a tiny tank with electric motor and explosives. The soldier would walk behind as it was controlled using wires and drive it under a tank or some other military target. The soldier was always 50m or so behind it so it would of been a scary ass maneuver. It was ahead of its time. Smart idea too.
I'm planning to try a truck starter to power a linear actuator to lift more weight, while keeping costs down. Thanks again for your great videos.
Excellent work, you are a very crafty guy considering.
You went way beyond the perimeters that I would have made, mine would have been way simpler like cave man to what I saw you just do. Excellent.
You can use the scissor lift to raise and lower the robot if you would take the ideas that you've got and somehow connect them with the with the scissor lift you can create something that's so you have something that's bigger than your to drive over you can use those to raise the units above that and drive right over it
independent steering and power, so awesome!!
Phase 2 is camera(s) ,sensors, and full automation. Disabled, I need it to work for me. (Cut grass, haul trailer and go dump it and return. (Find me and bring trailer from storage even.)
Third, I made good vacuum for Gras /leaves. It can pull that to clean up yard!
So we are working on same project. Motor options (wiper motors, wheel x chair used motors,
Or more expenssive strong motors for robots.
Wow you have been busy! :)
I feel your pain making these parts without a lathe. I have tried making a basic slip ring using a drill press in the past and it is complete blind luck that you don't screw up the alignment and have to start over. In the end I settled for a second hand automotive part from a car steering wheel. But in some cases, if you wanted something stronger i.e. not plastic, you will still have to make your own.
You Sir are the very definition of German Innovation. Amazingly executed and explained projects. I also see you are well versed in the nuances of all types of engineering from electrical to even mechanical. I am curious to know how you obtained such a broad background of engineering in general . Usually with RUclips channels dedicated to tech, they mostly focus on one type of skill, be it computer science, electronics, electrical or mechanical. Yours' is unique in being adept at all of them
Love the concept, it will be a huge challenge. Hope to see more soon.
Great video, the work on the wheel and motor shaft was exactly what I needed to learn about.
One way to overcome the issues of different motor speeds for each wheel in the Ackermann steering setup is to wire the wheel motors in series pairs. The front two motors are wired in series and the rear two motors are wired in series. This will allow the load on each motor to self regulate the speed. Not a good plan for a large powerful motor, but for something small, it works surprisingly well.
What if you use a power source with center tap (+12v, -12v, and 0) and control motors with only 2 switches instead of H-bridge? Also in this configuration, you can use chassis as a wire, and you don't need to cut the connection.
TheAntropod back emf will cause problems
That center finder is really cool idea. Great videos, very informative and well narrated.
I like the new intro music!
Your english is excellent. Cheers !
Great video.
During the apocalypse those motors will be free everywhere. But today, they are rather expensive! Even my local junkyard wants $30 each for them.
Wauw! Mount a camera tripod to that and you got yourself one very cool dolly!
Amazing as always! Looking forward to new videos.
I can't wait the time to finish college and start building my bench and making some fun stuff just like the old times (before college) :D
Great work, I’m looking forward to the video on Control and Programming. And also what interface you’ll use to control it.
Nice, finde es gut das die deutschsprachigen Bezeichnungen der Werkzeuge und Materialien dabei sind. Ich gucke haufenweise DIY Videos aus den Staaten und kann in English auch das gelernte erklären, mir fällt nur manchmal der deutsche Begriff für etwas nicht ein :D
Nice work! Subscribed :)
You want to put this under the fridge, so it comes to bring yo a beer to the chair
What you have made is called a 'swerve drive' and is used by some teams in the First Robotics Competition. There is a great amount of information available for those swerve drives. Here is an example of the awesome capabilities of your drive train: ruclips.net/video/kZHaTGiakZM/видео.html
Great reference. Is there a collection of ideas from First, an encyclopedia of techniques?
Another fun drive to experiment with would be the "bumper car" drive. A single central powered wheel with a 360 degree steering rotation, and fixed or swivel casters for the other rolling points.
You might like the Chief Delphi site www.chiefdelphi.com/forums/portal.php . Our FRC team used swerve with pretty good success last season. Here's a sample of how our swerve works swerve-model.herokuapp.com/ that uses information found here www.chiefdelphi.com/media/papers/2426 .
While there is no centralized place for FIRST techniques, I would agree to look at Chief Delphi, as Scott posted above.
fracture, I was thinking the exact same thing as I watched this video. Envisioning a giant inflatable wheel in the center and some small casters in the corners.
I'm not really sure where this robot build is going, but it's an interesting path.
Great video !! You're my hero ! Btw, please continue to post your video's on RUclips (instead of FB). I'm not on FB and I have very little interest to do so.
Philip Gevaert I have the identical comment.
;-)
old and commercial treadmills have big PM motors in them. I find free ones on Craigslist once a month or so. they usually have a motor for incline as well.
This is coming along nicely, good work.
@4:50 - Much appreciate the safety tip!
4 wheel steering? That's awesome!!!
Really like your robot build and the thought that went into it is very interesting. Well done; keep up the good work.
Premature comment: Yes! This is gonna make my day.
Next: "build the starship enterprise with washing machine motors"
Great work, love this project! Hope the completed robot will have an articulated arm or something like that.
What a great setup! If you want more power and torque look into electric wheelchair motors. I have built ebikes and other fun stuff with them on my channel. Sooooooooooo much torque!
how much weight can it move ? 100 - 300 lb?
plz reply fast
the wiper contacts could be used to get a measurement of the speed of the motor to use in a control loop wich keeps it constant up hills and over obstacles
FYI, Think wireless charging. How about a charging "mat" so your robot can wireless charge while it's working, so you can minimize the batteries weight. Even in a big warehouse. Induction coils should resolve the problem, while the mats are made with a aluminum printed pattern. Your welcome!
great video I can't wait to see how you design the rest of the robot. Cheers
Eat that Elon Musk ! Seriously, you have some interesting ideas and qualifications. But I think you forget that you have only one head and two hands. Try not to jump from one project to another. That lathe (maybe some other tools you have lying around) should be in working condition before you attack other monsters.
We need many heads and many hands for great projects like these!
I think I also cover most of those skills as shown at 26:45... only I don't tend to merge them into a single project like you are in this case!
Ideally, if you can detect the torque on each of the 4 tractor motor, you could allow more diverse steering angles. It could be done with strain gauge which detect minute distortion between the motor shaft and the wheel shaft in the same way as an electronic scale measure small bending on an aluminium base.
The closed loop would apply as much current needed to equalize the torque on each wheel. This would automatically adjust the rotation speed as needed given a specific steering.
The robot would still be set in motion with a target speed, but each motor would increase their torque together, to always match and the PID loop would change the torque command when approaching the target speed. In turn, each motor would have a separate PID loop to adjust the PWM to reach the specified torque.
I love to think about the geometry of things like this. Maybe the steering angle (distance of the pivot point in ackerman geometry) could be based on your desired speed. So when you're not moving you turn in place but when you're moving the turning radius moves further away based on speed.
At 6.34, we can see the wise moving from the drillpress when you're pressing on !
What you have in embreo is a mobil multi-directional static-platform.
That would make a great platform for a camera rig!
This is so nice. Good job!
Love the intro! Like an 80s montages.
i am using same motors and same h bridges. i didnt cut anything but its seems they are working fine together. i dont know why. i am using only the slow turning pins. may be its about that ? i thing the trick maybe i didnt put them in one framing.? they are isolated seperated frames.
nice project but i think one motor for steering is enough and all three wheels can connected by one chain belt
I just found out this channel and I love it.
Anyway, can you add tracks on that? Like a Leichter Ladungsträger Goliath?
I would love to see the shop projects with the Robert intermingled in. Maybe easier to edit videos with interjections of the robot that take longer.
Digging the new intro, dude! Catch you over on Facebook for more updates!
i enjoy the videos you make!! you motivated me to rebuild thing. you should make a robot like that with one more motor in the center and use parts of an Lawn Mower and use bumper grads from a robot vac to make it move around to cut the grass in a yard ! that would be supper cool to see!! keep up the cool videos!! for Baron
Instead of using rotary encoders, have you considered using laser mouse sensors? It's a neat way to recycle old mice; and new sensor chips from China are under 1.00 US D a piece with 1200 to 1600 steps/inch. Just run them across an enclosed/matte section of the output shaft. (Then backlash from the gearboxes won't even matter.) -- Use PID in the Arduino the control steps/sec or position.
For sensory data, you can grab an old Kinect cheaply off ebay; mount it to the top?
Raspberry PIs are impossible to find right now, but old laptops or NUCs can be sourced cheaply also. (I Just scored a 2.4ghz NUC with 8GB RAM and a 250GB SSD for around 40.00 US D. -- So it has a bit more compute power than an RPI anyway.)
What I find mind-boggling is the extent of your knowledge, innovation, and intrepidity; yet, for a man that can pull things from a scrapyard and re-engineer them, you don't think you'll be able to repair the drill press! Build a robot drive system, yes, but repair a drill press, no. Puzzling!
If you're planning to use this robot as a mobile camera tripod and record video from it while it is moving, it may be that the vibrations from the movement are too much for the camera to handle (especially if it doesn't have mechanical image stabilization). You talked about suspension earlier, but then I have seen nothing that could count as suspension on the robot: No springs or dampeners of any kind. Possibly even some dampening piece made out of rubber would already help a lot.
A most amazing piece of work!!!.... Will you show the assembly of the lathe for the Diy people?
Omg, I have to copy this, it's so awesome.
Love the new intro!
Your steering is going to need absolute positional sensing as well as relative positional sensing which is what your gray code encoders provide. For initialization at the very least. IE, at startup, it doesn't know the wheel facing orientation, eg a momentary sensor of some kind on each wheel. Kind regards
I think you could make an awesome wheelchair
It would be interesting if you made a vertical actuator for each wheel, that way you could extend one wheel higher than another, this would help you with ground clearance. This would also probably require you to rebuild your frame.
You could use 2 relay board with optocoupler as a H bridge for very cheap
A bit too late now, but what would have been really cool would have been slip rings for the wheel drive motors. Then you wouldn't have to worry about passing the 360 degree mark with your steering motors. :)
Incredible work! It's great to see videos like this. Definitely worth waiting for. Keep it up TPAI!!
Very nice indeed. You're an obviously clever guy.
New intro? Because I like it.
I have an idea for an invention that could make millions...be nice to see you give it a go
Are you building this for Ave's bartending robot?
Did this ever get made into anything with a purpose? I am absolutely sure something like this would be amazing for set props.
This is a awesome build
Wow, been following some of your video's and wonderbar!
Nice skillset roundup at the end.
Will you use the robot to extract melted plutonium from the cores of reactors that have suffered a melt-down?
Nice music, although I will miss the Morse code from the old one.
Well done. Very creative. Thank you.
A linkage can be designed since the inside wheels are a negative angle of the other and same for the outside wheels.
K
Weld up the missing material etc and file in keyway maybe, I hope you can save that little workhorse of a machine.
Very interesting. The encoders are really tough. They have to have ZERO interfearance with any dirt or dust. The smaller that wheel is, the more sensitive it is to a vibration or movement in any direction from the optical sensor. THEN - decoding the signals is too much work for an 8-bit arduino, you have to have a seperate quadrature decoder that is fast enough to keep up. Not easy.
The concept was interesting to see. Curious if / how the project has evolved from this.
Well.... I agree in general, encoder accuracy will be impacted by any injection of error such as dirt or misalignment. But these issues can be eliminated by using a different type of encoder architecture such as magnetic / induction and star ring gear design. These are commonly used for fuel injection timing and often installed in the crankcase filled with dirty oil!
External mount types are also used where dirt is often impossible to eliminate.
Nice project! I know that this is an old video, nonetheless, I wonder if 2 of the 4 wheels could be simply casters with out controls or motors. The powered wheels would be at 2 corners. As I am imagining it you could still replicate any direction or manouver that 4X powered wheels could perform
This intro was dawn awsome!
Keep up the good work man!
hello I have a similar problem. I literally burned out my mosfet motor driver.
can you kindly explain how cutting connection to the wiper motor enclosure works. it is not really clear.
is there a way I can do that without having to open the motor?