### Author Topic: making a robot  (Read 12603 times)

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#### boyardee12

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##### making a robot
« on: February 15, 2008, 08:30:44 PM »
Well i have a dilemma  I need to know is my idea possible to make for a beginner and a brief description of what mechanism to use.

First a little background information. I'm making a remote controlled robot that needs to fit in a 30x30x30cm box with no top or bottom. Box weighs 4~5 lbs.  I need to pick the same box up and lift it then place it back down over objects.

To lift the box my idea is to make a gripper. It has  to be less than 30cm in length but then extend over 30cm to grab the box. I'm thinking it would look kinda like this

Then to lift the box (only need to lift it about 3-4 inches from the ground) I'm thinking of putting the gripper on a little forklift or would it be easier to have the gripper be able to tilt.

Lastly, how would i go about making this gripper do i use 2 sets of rack and pinion gears one for each side?? I have no idea any input would be great.

Extra information about regulations:
Each robot circuit must be energized by one or more commercial batteries which do not exceed 9.6 volts. If multiple batteries are used, they may be connected in series or parallel as long as the voltage output does not exceed 9.6 volts. The voltage stated on commercial batteries will be accepted.
Each robot function (such as drive train, arm, etc.) may have its own independent circuit, source of electrical energy, and control mechanism.

So is 9.6 volts the max i can use?
« Last Edit: February 16, 2008, 02:10:27 PM by boyardee12 »

#### boyardee12

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##### Re: making a robot
« Reply #1 on: February 16, 2008, 02:20:07 PM »
Can someone help me please if you dont wanna read through everything then here a basic question i need answered.

What mechanism do i need to make the robot grip as pictured above???

The reason i need this answered is i have to go buy parts soon bfore the store closes.
« Last Edit: February 16, 2008, 02:24:43 PM by boyardee12 »

#### airman00

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##### Re: making a robot
« Reply #2 on: February 16, 2008, 05:34:52 PM »

the orange part turn by means of gears or just straight connection to a motor
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#### boyardee12

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##### Re: making a robot
« Reply #3 on: February 16, 2008, 05:59:57 PM »
thanks thats a good idea  the width is not  a problem now but i just gotta watch out a little for the length of the entire robot not exceeding 30 cm but i can fix that problem easily

also i see in this the red part (in your photo) is is some kind of motor the pulls in and out is that a good idea ?
« Last Edit: February 16, 2008, 06:08:00 PM by boyardee12 »

#### airman00

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##### Re: making a robot
« Reply #4 on: February 16, 2008, 06:30:45 PM »
you can have the red piece pull in

OR

just have a motor with two gears by each orange part. The turning on the motor will turn those two gripper pieces.\

Ever though of buying this and a servo http://www.robotstore.com/store/product.asp?pid=267&catid=1551
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#### boyardee12

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##### Re: making a robot
« Reply #5 on: February 16, 2008, 07:18:50 PM »
well i would have to make a big one since i need to open up a   a little over 30cm which is like 1 ft and that one only opens to 3.3 cm.. I would need big gears and i strong motor to make the design earlier right? (also keep in mind the box is 4-5lbs) Also "each circuit must be energized by one or more commercial batteries which do not exceed 9.6 volts"is that enough for voltage to support a motor like that? .....Sorry im really new at this and i didnt know what  i was getting into when i decided i was gonna be the robot person. One last question is it better to tilt or lift the box?

#### airman00

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##### Re: making a robot
« Reply #6 on: February 16, 2008, 07:31:50 PM »
Check out the Roboduino, Arduino-compatible board!

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#### boyardee12

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##### Re: making a robot
« Reply #7 on: February 16, 2008, 07:38:25 PM »
are you saying make one like that or buy that because that is also to small it dosnt open to alittle over 30cm. I have already look at a lot of gripper but they all don't open up to more than a couple of inches.

#### kd5kfl

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##### Re: making a robot
« Reply #8 on: February 16, 2008, 08:42:25 PM »
Use linear actuators. Or one linear actuator.

#### airman00

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##### Re: making a robot
« Reply #9 on: February 16, 2008, 09:21:15 PM »
are you saying make one like that or buy that because that is also to small it dosnt open to alittle over 30cm. I have already look at a lot of gripper but they all don't open up to more than a couple of inches.

make one like that , its very simple design
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#### boyardee12

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##### Re: making a robot
« Reply #10 on: February 16, 2008, 10:03:49 PM »
A linear actuator seems to fit perfect but im looking at prices for it online and they cost to much for me Like \$100+ im only a high school student. Is there an alternative to it??? and what kind of moltor would i need to tilt the gripper
« Last Edit: February 16, 2008, 10:27:42 PM by boyardee12 »

#### airman00

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##### Re: making a robot
« Reply #11 on: February 16, 2008, 10:31:15 PM »
servomotor to tilt gripper
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#### boyardee12

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##### Re: making a robot
« Reply #12 on: February 16, 2008, 11:36:57 PM »
ooo my bad airman00 u suggested earlier  that orange part be turned by gears and i thought you meant the light orange part lol know i get what you are saying thanks for all the help now i need to get some parts

#### airman00

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##### Re: making a robot
« Reply #13 on: February 16, 2008, 11:39:03 PM »
ooo my bad airman00 u suggested earlier  that orange part be turned by gears and i thought you meant the light orange part lol know i get what you are saying thanks for all the help now i need to get some parts

no problemo

post pics and details of your construction of the gripper
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#### boyardee12

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##### Re: making a robot
« Reply #14 on: February 17, 2008, 01:19:19 AM »
and the tilting should be some how like this right

#### airman00

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##### Re: making a robot
« Reply #15 on: February 17, 2008, 02:19:12 AM »
and the tilting should be some how like this right

exactly!

now you either have one rotating part or have both parts on gears to be turned in opposite directuons by one motor
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#### boyardee12

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##### Re: making a robot
« Reply #16 on: February 18, 2008, 03:37:56 PM »
This might seems like a stupid question but if i set two gears by each orange part than a gear on the motor than wont one clamp go one way and the  other side will go the same way so how do i get it to go in th eopposite direction so i can grip the box

#### airman00

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##### Re: making a robot
« Reply #17 on: February 18, 2008, 04:31:58 PM »
This might seems like a stupid question but if i set two gears by each orange part than a gear on the motor than wont one clamp go one way and the  other side will go the same way so how do i get it to go in th eopposite direction so i can grip the box
I meant one gear by each part , and the servo powering one gears

say the top gear was directly servo powered and connected to one orange piece, and the second gear was connected to the other orange piece
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#### boyardee12

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##### Re: making a robot
« Reply #18 on: February 18, 2008, 09:34:11 PM »
thanks for clarifying i see now

#### airman00

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##### Re: making a robot
« Reply #19 on: February 18, 2008, 10:01:52 PM »
thanks for clarifying i see now

no problemo

Just make sure you document how you built your gripper, pictures every step of the way, descriptions
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#### boyardee12

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##### Re: making a robot
« Reply #20 on: February 19, 2008, 12:06:38 AM »
Yes, will do still have to go buy parts tho which i should of done today.  Just to make sure with the gears method if i use screws to assemble the gripper, I'm suppose to untighten the bottom of the light orange pieces connecting to the pink piece so it moves freely while the top is tighten to the grip. And then the dark orange pieces at the top connecting to the grip should be untighten also. Am i correct?

« Last Edit: February 19, 2008, 12:14:12 AM by boyardee12 »

#### airman00

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##### Re: making a robot
« Reply #21 on: February 19, 2008, 05:29:07 AM »
Yes, will do still have to go buy parts tho which i should of done today.  Just to make sure with the gears method if i use screws to assemble the gripper, I'm suppose to untighten the bottom of the light orange pieces connecting to the pink piece so it moves freely while the top is tighten to the grip. And then the dark orange pieces at the top connecting to the grip should be untighten also. Am i correct?

yes the orange pieces are meant to move freely, and you'll have to put them on axles .
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#### boyardee12

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##### Re: making a robot
« Reply #22 on: February 19, 2008, 10:46:45 AM »
kk i think im going to use only one light orange part for each side so 2 total instead of four

#### boyardee12

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##### Re: making a robot
« Reply #23 on: February 19, 2008, 09:50:01 PM »
So i went out to the local hobby shop and they had the servo i was wanted for the tilting however they didn't have any gears  so  left without buying anything. I guess ill buy them online. Then i went to home depot to look for the hardware parts and i walked down random aisles looking for parts and i found some things which ill post pics tomorrow. Basically for hardware i just need to find some something that will grip Plexiglas good enough.

Here the servo im thinking of  getting for tilt. Its good enough right?
http://www.servocity.com/html/hs-645mg_ultra_torque.html

How many teeths does the gear with a servo come with because im looking for a 5:1 ratio for gears and  i think this type of gear is the one i need to buy but just need the right size. Any input?
http://www.servocity.com/html/48_pitch_acetal_hub_gears__1_8.html

Also for the gripper should i use a dc motor or a servo?

#### airman00

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##### Re: making a robot
« Reply #24 on: February 19, 2008, 09:55:16 PM »
servo or dc motor is fine for the gripper , but servos have positional control so you can know how open the gripper is , with DC motors themselves you can't tell.

Servos have a built in gearbox and they have speed control through PWM (pulse width modulation)

Why would you need an extra gear outside the servo, servos have speed control so you don't  need the gear to reduce RPM.

How heavy plexiglas are you talking about tiliting?

And rubber should grip plexiglas fairly well.

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#### boyardee12

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##### Re: making a robot
« Reply #25 on: February 20, 2008, 09:07:33 PM »
The weight of the box should be around 5 lbs

And i saw the gear in here  and i thought i would need a gear hooked on the servo and a gear on the tilting base. So i dont need that big gear i can just hook the servo to the titling base?

#### airman00

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##### Re: making a robot
« Reply #26 on: February 20, 2008, 10:17:44 PM »
well the ultra torque servo has 133 ounces of torque  = 8.3125 pounds of torque

so no big extra gear is needed to increase the torque , since the servo alone can provide 8.3 lbs. of torque.
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#### boyardee12

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##### Re: making a robot
« Reply #27 on: February 21, 2008, 08:25:05 PM »
ok well now i just need gears for the gripper and think these are good enough.  Will I'll be able to use them without using a vex brand servo? http://www.vexlabs.com/vex-robotics-gear-kit.shtml Will I'll be able to use them without using a vex brand servo?
I think im just going to get two of the servos i posted a link to earlier. With servo i can revers the direction more easily than a dc motor right? (To open and close the gripper)
I need to hurry up because im behind schedule.....
« Last Edit: February 21, 2008, 08:58:30 PM by boyardee12 »

#### airman00

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##### Re: making a robot
« Reply #28 on: February 21, 2008, 09:29:21 PM »
sure you can use a vex servo and servos are reversible

I assume you know how to control the direction of the servo with a microcontroller?
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#### boyardee12

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##### Re: making a robot
« Reply #29 on: February 21, 2008, 10:24:34 PM »
I'm not using a vex servo but im assuming that you meant that those gears can only be compatible with vex servos. ( i would need to hook a vex gear on the servo for the gripper.. I think )  I'm hoping that you didn't mean that and i could put the vex gear on a hs-645mg servo because I'm having trouble finding packs of gears.

Well maybe i i could use the servo gear that comes with it to turn of of side of the gripper with the vex gear and that gear will turn the other side. But doesn't the gear that comes with the servo have the same pitch as the vex gears? and i don't know if they do or don't.

I dont know how to control the direction a micro controlle.r but it's ok cause after im done building it i will probably hand it over for my partner to work on getting in the final stages.