Balancing Robot

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Balancing Robot by vahid_you2004 on August 8, 2008

Table of Contents intro: Balancing Robot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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Video . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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step 1: Things you need . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3

step 2: Motor, Grears, Shaft, and Wheels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5

step 3: Attach robot neck and head . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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step 4: Making the sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

8

step 5: Connecting the switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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step 6: Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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step 7: Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Video . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Related Instructables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Advertisements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Make Magazine Special Offer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Comments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

http://www.instructables.com/id/Balancing_Robot/

intro: Balancing Robot This is a very simple robot that uses a simple switch as a sensor and stands on only two wheels with inverted pendulum mechanism. When the robot is going to fall the motor starts and moves the robot to the direction it is going to fall, so the motor torque about the center of gravity that is higher than the motor makes the robot balanced. You can also find this tutorial on my homepage

Video

http://www.instructables.com/id/Balancing_Robot/

step 1: Things you need To make this robot you need following parts and tools: small electric motor some gears (or a motor with gearbox) a shaft two wheels some sheets of plastic to make bearings and the robot neck two battery holders 4 AA batteries one button cell one SPDT (single pole double throw) switch with a metal lever one toggle switch for the on/off switchs one nail some wire soldering iron some glue

http://www.instructables.com/id/Balancing_Robot/

http://www.instructables.com/id/Balancing_Robot/

step 2: Motor, Grears, Shaft, and Wheels In this step you must make a system to moves the robot you can make it easily by adding some gears to a simple small motor, then connect it to a shaft and assemble it two wheels. You can also use a motor and gearbox. It does not matter how you make it.

Image Notes 1. Motor 2. Gears

http://www.instructables.com/id/Balancing_Robot/

3. Wheel 4. Shaft 5. Bearing

Image Notes 1. Plastic Sheet

http://www.instructables.com/id/Balancing_Robot/

step 3: Attach robot neck and head Use glue to attach a sheet of plastic to the motor. Then put some glue on one side of battery holders and attach them to the top of the plastic sheet.

Image Notes 1. Plastic Sheet

http://www.instructables.com/id/Balancing_Robot/

step 4: Making the sensor Solder a button cell to the SPDT switch lever. Make the nail head hot on a flame and put it on the plastic sheet on the motor in a position that when the robot stands vertically the button cell touches the ground. Then attach the switch to the robot with glue.

Image Notes 1. SPDT Switch 2. Button Cell

step 5: Connecting the switch Solder a wire form positive pole of one of battery holders to the negative pole of the other battery holder and attach the toggle switch to it. Then attach the other side of the switch to the motor.

http://www.instructables.com/id/Balancing_Robot/

Image Notes 1. Solder this leg to battery holder 2. Solder this leg to the motor

step 6: Wiring Now it is time to solder the robot wires. Note that you must solder the wires in a way that robot moves to the direction that is going to fall.

http://www.instructables.com/id/Balancing_Robot/

Image Notes 1. From the switch 2. From the sensor

Image Notes 1. From the sensor 2. From the sensor

http://www.instructables.com/id/Balancing_Robot/

Image Notes 1. To the motor 2. From the batteries

step 7: Testing The robot is now completed and it is time to test it. Put 4 batteries into the battery holders and turn on the switch. Try to change the position of the sensor to make the robot works better. If the robot works inverted swap the red and blue wires on the sensor or on the battery holders.

Video

http://www.instructables.com/id/Balancing_Robot/

Image Notes 1. To the motor 2. From the batteries

http://www.instructables.com/id/Balancing_Robot/

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Comments 50 comments Add Comment

thepelton says:

view all 134 comments May 13, 2009. 10:23 AM REPLY

This is cute! I love it!

tom95 says:

May 10, 2009. 2:37 AM REPLY

Nice robot, but couldn't you use a mercury switch

ReCreate says:

May 12, 2009. 8:08 PM REPLY

Sure,who would not want to use a toxic Metal Composed switch?:P

tom95 says:

May 12, 2009. 10:37 PM REPLY

OK then use a tilt switch

mcnd says:

May 12, 2009. 8:21 PM REPLY

I'm going to make a segway scooter for myself !!

KahlZun says:

May 7, 2009. 7:48 PM REPLY

I think using bigger wheels would help, the small ones are too hard to accurately control

seattled says:

May 7, 2009. 2:27 PM REPLY vahid you have a great mind dude but your building skills have to improve, this is a great little robot. you should improve the appereance of it... congrats though..

et334 says:

Apr 27, 2009. 8:38 AM REPLY

aww this looks cool i wanted to check your webpage but it "has exceeded its daily bandwidth quota" ill try again tomorrow nice 'ible btw

vahid_you2004 says:

Apr 30, 2009. 4:08 AM REPLY

I will make my new website a few month later.

bobbonought says:

Apr 27, 2009. 1:22 AM REPLY it looked complicated but it is really simple. but there are only two problems and they are that it is always moving and its center of gravity is way to high

PlayPatterns says:

Apr 23, 2009. 5:16 PM REPLY

will you let my hamster ride this?

GEEK1 says: how long is the record that this stayed up?

http://www.instructables.com/id/Balancing_Robot/

Apr 21, 2009. 7:18 PM REPLY

dagenius says:

Apr 21, 2009. 2:44 PM REPLY

Is that circuit a kind of H-bridge?

vishnu_ad1993 says:

Apr 16, 2009. 8:49 AM REPLY

come on brother!!! you do great things i love it dude!!!!!!!!!!!!

Sagar Gondaliya says:

Apr 20, 2009. 2:38 PM REPLY

yay i'm not the only indian dude on this site. thnx

imakethings says:

Apr 7, 2009. 3:15 AM REPLY

isnt this a kind of gyroscope application?

vahid_you2004 says:

Apr 8, 2009. 4:20 AM REPLY

No gyroscope works differently. It resists rotation because of its inertia.

amando96 says:

Mar 30, 2009. 2:33 PM REPLY

very idea, will have to try it! :D

hominid says:

Mar 21, 2009. 9:51 AM REPLY This is a very good idea. With the music and the robot falling over I feel it is like a sad movie about a person with a disease and their struggle to walk, shakey or not. End the video with the robot standing.....Please..... or I may do something I might not get to regret. (Just joking for the record). :-)

amando96 says:

Mar 30, 2009. 2:33 PM REPLY

LOL! best drama i've seen!

superballistix says:

Mar 21, 2009. 1:48 PM REPLY

Very creative!! I am going to build my own version of this robot!!

elvenglenn says:

Mar 3, 2009. 9:27 PM REPLY

NICE one

Wafflicious says:

Feb 21, 2009. 8:14 AM REPLY

I just thought of how to build it with the lego mindstorm. I will post pictures if it works

crrake26 says:

Jan 29, 2009. 6:19 AM REPLY WOW man!!! this is a REAL SIMPLE robot to make without any electronics and stuff!!! btw, why do u use 4 batteries? Isn't 2 enough?? I sure am going to try this out. Try to post another simple one like this later.

Unit042 says:

Jan 2, 2009. 6:50 PM REPLY (To the writer of this instructable) Dang! Yours can balance in boh directions. The one I built some time back uses a single ople, single throw temporary switch, made from a couple of paper clips and a spring. I also used only one motor, and only one battery, so no, I didn't use any split power supply tricks, just a nine volt battery. Mine balances by continually falling forward. When the whisker detects it's gone too far, it twitches the motor forward. The motor's power is cut; so the robot is stable, but still falling forward.... and... another twitch! So, I used three parts: single motor single battery SPST switch You used five: Single motor equivalent of two SPST switches (or one SPDT) two battery packs, giving 2 separate power sources to choose from via the SPDT.

http://www.instructables.com/id/Balancing_Robot/

But, yours balances both directions, so congrats! I only skimmed your 'ible, but what I've seen so far is awesome!

boyrock375 says:

Dec 30, 2008. 5:27 PM REPLY if you want to keep it from falling over in one direction then put a switch on the other side but reverse the polarity of the motor so when it falls that way the motor will spin in the other direction.

Fletcher says:

Aug 20, 2008. 8:22 AM REPLY My son and I are building one of these using Budsiskos' idea of replacing the weighted mini switch with ball bearing tilt switches. We're using an alreadyassembled motor/gearbox (New Bright-brand RC car, found at Wal-Mart for $5.00.) We hope the tilt switches will give us more stability. With the switch vahid_you2004 used the motor is always running one direction or another. There's no 'stall point' that turns the motor off if it happens to be perfectly balanced. We'll be using two ball bearing tilt switches, arranged to allow a stall point when perfectly level.

Fletcher says:

Oct 1, 2008. 7:12 PM REPLY FYI - Haven't forgotten about this. Son and I worked on ours tonight (soldered up the H-bridge, freeform BEAM-style. It was his first time soldering.) Hbridge isn't working, so I need to troubleshoot it. More as/when it happens....

Fletcher says:

Nov 22, 2008. 10:59 PM REPLY Update: Haven't found much time to work on this, but have made progress. H-bridge works well, as do tilt switches. Motor/gearbox were the weak link (slow, underpowered) so they're being replaced with something more stout. Initial results look promising though.

vahid_you2004 says:

Nov 25, 2008. 10:36 AM REPLY

Using H-bridge is very useful and helps the motor work faster and more powerful.

RichardBronosky says:

Aug 28, 2008. 10:36 PM REPLY

### The "ideas of how to improve the design" thread starts here!! ### I've been thinking about this for a while now. I like Fletcher's idea of "ball bearing tilt switches", but I really want to keep the commodity construction (no special parts) aspect. I think I will build a 5 stage pendulum switch (neutral plus 2 steps in each direction) to give finer grain control over the balance and make it so only the wheels touch the ground. I'd also like to learn lessons from tight rope walking and "pool cue" balancing. 1. Tight rope walkers use a sick to keep their balance, similar to the way it is your instinct to put you hands out to the side when walking on a curb wall or rail road track. So, I'd like to line the batteries up horizontally front to back at the top of the shaft. 2. As Scurge pointed out, it's easy to balance a pool cue on your palm. However it is nearly impossible to balance a pencil. So, I'll make a telescoping shaft so I can find the sweet spot for my motor torque and gear box combination. This is so exciting! I want to hear and see what others come up with.

Fletcher says:

Aug 29, 2008. 5:15 AM REPLY I don't know about 'improving' the design, as vahid_you2004's approach was to make this as simple as possible (and added components and complexity just lead us further toward the 'Segway' end of the scale.) Noting that, I think there's an opportunity to get improved performance while still keeping a 'mechanical feedback' design. My thoughts/approach thus far: -The NTT ball bearing switch idea (again, credit to budsiskos) needs to allow for some way to adjust the mount angle of the two switches. They trigger at 10 degrees from level, and the mounts should be adjustable so that you can 'dial in' the correct angle. I've made hinged mounts that use a fine-pitch screw to move one end up or down as appropriate. -We're using a Tilden-style 6 transistor H bridge for motor control -While we're building ours to allow for a stall point when balanced, another consider may be motor braking. (When the posts of an electric motor are connected to one another, the generator effect of the motor works against the motor itself, and the motor 'brakes.') There are several motor control circuits, many of them fairly simple modifications of an H bridge, that would add that function. Many people in these comments have compared this balancing robot to a Segway, or suggested building a larger version to ride. What they're overlooking is that this device is incapable of moving forward or backward (or turn, for that matter); simply balance. It'd be interesting to see this mechanical feedback idea incorporated into a design that could actually move. At a glance, I'd say that you'd do that not by balancing the drive wheels, but by balancing the robot's mass at some hinge/waist point over the drive wheels.

hal9000 says:

Sep 10, 2008. 6:56 AM REPLY

Great project. A nice instructable. Thanks for sharing.

sbot says:

Sep 8, 2008. 1:43 AM REPLY

sweet concept...hats off!

carpespasm says: Hey! This isn't a pie! Cool little mechanism there. Maybe lowering the batteries would allow it to work better.

http://www.instructables.com/id/Balancing_Robot/

Aug 10, 2008. 11:37 AM REPLY

vanbo says:

Aug 30, 2008. 2:28 AM REPLY

Maybe putting a big (centred) brass brazing rod on top, with equal length for each end?

vahid_you2004 says:

Aug 11, 2008. 11:04 AM REPLY

No, in fact higher batteries moves the center of gravity of the robot higher and it makes it to balanced better.

YummyPancakes says:

Aug 29, 2008. 5:31 AM REPLY No, in fact higher batteries moves the center of gravity of the robot higher and it makes it to NOT balanced better. Lower batteries=lower COG=Better balancing.

vahid_you2004 says:

Aug 30, 2008. 10:54 AM REPLY Are you sure! When the CG is higher the moment of inertia is bigger and so the falling acceleration is lower so the robot has more time to balance itself. TRY TO BALANCE A LONG STICK AND A SHORT STICK!

dagenius says:

Apr 21, 2009. 2:46 PM REPLY Long and short is different, because not all of the weight of the stick is at the top, but if you had a long stick with a weight at the end, then it would be harder to balance.

KLUTZYengineer says:

Apr 15, 2009. 7:32 PM REPLY

That was a very good analogy.

carpespasm says:

Aug 30, 2008. 12:22 PM REPLY The thing is it isn't about a long stick or short stick, it's about balancing the strength of your motor with the weight on your upright stick. If you try to balance a sledge hammer on it's handle then you'll see that you can't overcome it's momentum easily once it starts getting off balance and begins to fall over. Likewise, balancing a short stick doesn't give you enough time as it falls over to counter it's fall without overcompensating. You have to strike a balance between the two. The height and the weight both play a part in how well your robot will react, and the best setup would vary based on how much torque your motor has to overcome the momentum and how quickly it can react to rapid sways of the pendulum.

dagenius says:

Apr 21, 2009. 2:47 PM REPLY

You got it.

atokad33 says:

Oct 13, 2008. 8:52 AM REPLY heres an idea, extend the plastic strip up and widen it to create friction with the air to slow down the falling speed and move the batteries down to give it a lower center of gravity

vahid_you2004 says:

Oct 14, 2008. 12:56 PM REPLY

A sheet of plastic is a good idea but lowering the CG is not good.

vahid_you2004 says:

Aug 31, 2008. 11:40 AM REPLY The important thing is the CG and the total mass of the robot. More mass needs more torque. To balance two same robots with the same mass the robot with higher CG can be balanced better.

YummyPancakes says:

Aug 30, 2008. 12:07 PM REPLY

I suppose1 you're right. You see, I was thinking about those "Wobble Clocks" that are weighted at the bottom. No matter how far you tip them, they always wobble back upright. 1

Well, actually, I can't suppose if you're right, because you were a little hard to understand there.

viacin says:

Sep 1, 2008. 5:59 PM REPLY ever looked inside a weeble wobble? they don't put the weight at the top, it's at the very bottom. BUT this robot just wouldn't be as fun if it didn't TRY to fall over, it's kinda the whole point. :D

http://www.instructables.com/id/Balancing_Robot/

Polymorph says:

Sep 2, 2008. 9:29 AM REPLY But this doesn't balance by putting the COG below the axle. The whole point is that the COG is -above- the axle yet it balances itself dynamically. A weeble works because the bottom is very wide and the weight is concentrated in the -center- of the bottom, so as the Weeble tilts, the weight rises.

Fletcher says:

Aug 29, 2008. 10:12 PM REPLY I'm not sure what more can be said to address this misconception that it would balance better with the weight moved lower. It's not about lowering the center of gravity; it's about reducing the polar moment. Case in point; vahid_you2004's design works better because of the high position of the batteries. If you aren't convinced, follow his design, build one, and try it both ways; with the batteries mounted high and mounted low.

view all 134 comments

http://www.instructables.com/id/Balancing_Robot/