Society of Robots - Robot Forum

Mechanics and Construction => Mechanics and Construction => Topic started by: siddharthm87 on January 09, 2008, 11:30:48 AM

Title: torque
Post by: siddharthm87 on January 09, 2008, 11:30:48 AM
hey i am new to robotics..can u guys  tell me what exactly the torque specifications means....

#Torque: 1.1 kg.cm at 4.8 V -1.3 kg.cm at 6.0 V (15.27/18.05 oz.in at 4.8/6.0V)

waht do you guys think about hitech micro hs-55 servo motor????
is it good enough to build a obstacle course robot???
Title: Re: torque
Post by: Fredrik Andersson on January 09, 2008, 01:27:10 PM
At first, i reacted on the low torque, but then i saw it was a micro servo. So it depends entirely on the rest of the robot. Are you going to build it small? Is it a weeled or legged robot?
Title: Re: torque
Post by: Admin on January 09, 2008, 02:06:18 PM
calculate!

http://www.societyofrobots.com/RMF_calculator.shtml
Title: Re: torque
Post by: siddharthm87 on January 09, 2008, 05:53:38 PM
it is a wheeled robot.
i am designing a robot which can navigate through an obstacle course with decent speed.
Title: Re: torque
Post by: SmAsH on January 10, 2008, 05:09:17 PM
hmm.... it may work but u'd have to put at least 3/4 wheels if its a normal size robot.....like 8-15 cms long but u could probibly get away with 2 if its a small robot like 5-8cms..
anyways good luck buddy  ;D
Title: Re: torque
Post by: cooldog on January 10, 2008, 05:14:06 PM
if you are building a out door robot go with 4 hs-311 servos it gives you 4 wheel drive exelent torque and desent speed
Title: Re: torque
Post by: siddharthm87 on January 11, 2008, 02:49:36 AM
hey thanks for your all your replies:-)
 can you suggest which servo motor should i use if time is also taken into consideration???
 with good speed!!
 the complete weight of the chasis is 600g ms-700gms
 the dimensions of the chasis is 20x20x20 cms
Title: Re: torque
Post by: cooldog on January 11, 2008, 06:45:37 AM
in m y opinion HS-311 is the best rounded servo but there are lots of faster ones
Title: Re: torque
Post by: siddharthm87 on January 11, 2008, 10:14:34 AM
hey how about.4 kg.cm....
but will there be any problem if use  a servo which has high torque???
Title: servo motor...
Post by: siddharthm87 on January 11, 2008, 01:35:16 PM
is it good to desgin wheeled robot with ..
                            2 POWERED SERVO MOTORS????
                                   
                                               or
 
                            4 POWERED SERVO MOTORS??

1.the weight of the robot is nearly 1000gms.
2.speed is a criteria.
3.the toque of the motor is 4 kg.cm
4.the terrain is flat


       
Title: Re: servo motor...
Post by: SmAsH on January 11, 2008, 02:07:05 PM
if you know a bit more about electronics than the average noob....you should be able to go four wheel...me i go two...anyway why dont you like add up the positive and negative of each the decide which one is better ;D
Title: Re: torque
Post by: Admin on January 11, 2008, 02:21:29 PM
again, you should calculate how much torque you need. 8)

otherwise it's all guesswork . . .
Title: Re: torque
Post by: cooldog on January 11, 2008, 03:11:42 PM
is the terrain indoors or out

outdoors
4 wheel drive with good wheels

indoors
2 wheel drive with racing tires
Title: Re: torque
Post by: siddharthm87 on January 12, 2008, 10:46:38 AM
hey,

  the exact speed of the robot is not a problem.
  so is it ok to use high torque dc motors instead of servo motors???

  for example...if we detect an obstacle using sensor we can inform the dc mtors to slow down and the feedback     isn't necessary because the bot is any way slowing down.right??
Title: Re: torque
Post by: ed1380 on January 12, 2008, 10:57:03 AM
you could do that. using servo's is easier though. output a pwm and you're done.

with motors you need a h-bridge or drivers.  programming could be easier or harder. depends on what you use
Title: Re: torque
Post by: junior000 on January 12, 2008, 11:30:12 AM
yeah.....have two h-bridges and drivers on my board!

the robot i am going to design will have 2 powered wheels!!

now.....

1.if i use dc motors will the controlling of the robot be ok???
2.what about using stepper motor??
Title: Re: torque
Post by: ed1380 on January 12, 2008, 01:55:57 PM
yeah.....have two h-bridges and drivers on my board!

the robot i am going to design will have 2 powered wheels!!

now.....

1.if i use dc motors will the controlling of the robot be ok???
2.what about using stepper motor??
all depends on how good you rpgramm it

stepper motors could be used, but you'dd need a special motor driver for it
Title: Re: torque
Post by: junior000 on January 14, 2008, 05:42:10 AM
this is how i am going to design it....

two dc motors at the back will drive the  whelled robot and a servo motor will be used to turn the direction of the robot...will that be ok???

Title: Re: torque
Post by: airman00 on January 14, 2008, 07:06:50 AM
why not just do differential drive? (like a tank )

why do you want steering like in a car?
Title: Re: torque
Post by: junior000 on January 14, 2008, 07:31:35 AM
hey there are lot of obstacles in b/n ...so it is very imp to have precise and good steering!
this is my thinking.

this is what the event looks like

           www.myfirstbot.blogspot.com



       
Title: Re: torque
Post by: junior000 on January 14, 2008, 07:35:25 AM
i am using pic microcontroller 18f4550.

i am still a rookie in robotics..so it is taking a bit of time understanding things.
but i guess i will catch up with things
Title: Re: torque
Post by: airman00 on January 14, 2008, 07:43:49 AM
do differential drive , have two motorized wheels and a caster
Title: Re: torque
Post by: junior000 on January 14, 2008, 08:53:43 AM
hey there are lot of obstacles in b/n ...so it is very imp to have precise and good steering!
this is my thinking.

this is what the event looks like

           www.myfirstbot.blogspot.com

  but using differential drive will slow it a bit right????

 
Title: Re: torque
Post by: airman00 on January 14, 2008, 09:53:17 AM
no it wont really slow it down
Title: Re: torque
Post by: junior000 on January 15, 2008, 02:59:05 AM
one last question....

if you have to choose b/n dc or servo's which one would u choose???(take speed into consideration)
Title: Re: torque
Post by: SmAsH on January 15, 2008, 03:41:11 AM
if b/n means before i would say dc motors (theyre what i normally use) if its torque you need. ive never used a servo before but heard theyre good....anyways see what everyone else says...

~smash ;D
Title: Re: torque
Post by: Bubbles on January 17, 2008, 12:01:31 AM
personally i would use servos as they already have their own gearing systems built in and can get pretty good speed/torque (not to mention they are waaaay easier than using motors, and less expensive)  ;D