Transcript VEX Torque
Torque
J.M. Gabrielse
Outline fun with seesaws •
•
a big person and a little person
two little people in different spots
J.M. Gabrielse
What Will Happen?
Nothing J.M. Gabrielse
The Bigger Torque Wins In this case the torques are equal so they balance out.
J.M. Gabrielse
What Will Happen?
Why?
J.M. Gabrielse
The Bigger Torque Wins A force is a push or a pull.
F
The
BIG FORCE
creates a bigger torque than the little force .
F
J.M. Gabrielse
What Will Happen?
Why?
J.M. Gabrielse
The Bigger Torque Wins Both forces are the same size. The
BIG DISTANCE
from the pivot point creates a bigger torque than the little distance .
F F
(pivot point = fulcrum) J.M. Gabrielse
What Will Happen?
J.M. Gabrielse
The Bigger Torque will Win a
BIG FORCE
with a little distance
F
a little force with a BIG DISTANCE
F
Which torque will be bigger?
J.M. Gabrielse
Calculate Torque (T)
F T = F force d distance Note: d is measured perpendicular to F d pivot point J.M. Gabrielse
What Will Happen?
F = 200 lb d = 10 F = 50 lb d = 70 in J.M. Gabrielse
Use the Equation F = 200 lb d = 10 in T = 2000 in lb
F
F = 50 lb d = 70 in T = 3500 in lb
F
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The Bigger Torque Wins T = 2000 in lb T = 3500 in lb J.M. Gabrielse
Which arm has more torque on it?
Arm 2 F 2 =
10 lbs
Arm 1 d 1 F 1 =
10 lbs
d 2 J.M. Gabrielse
Which arm has more torque on it?
F 1 = F 2 d 1 > d 2 - so Arm 2
T 1 > T 2
F 2 =
10 lbs
Arm 1 d 1 F 1 =
10 lbs
d 2 J.M. Gabrielse
Motors Provide Torque Torque from the motor makes the wheel spin.
The maximum torque from a Vex motor is 6.5 in*lb.
J.M. Gabrielse
F = 0.225 lb Motor Example d = 15 in pivot point
motor
How much torque would the motor need to supply?
T = F d = 0.225 lb x 15 in J.M. Gabrielse
F = 0.225 lb Motor Example d = 15 in pivot point
motor
How much torque would the motor need to supply?
T = 3.375 in lb J.M. Gabrielse
F = 0.225 lb Motor Example d = 15 in pivot point
motor
The motor has more than enough torque to lift a tube, but it also has to lift the weight of the arm.
J.M. Gabrielse
Can’t loosen a screw?
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You need more TORQUE!
Push harder (more force) -or Use the long side of the allen wrench (longer distance) J.M. Gabrielse
Two ways to hold an Allen wrench • Speed: fast Torque: low • Speed: slow Torque: high J.M. Gabrielse
Use Torque to Tighten Screws Or your robot will end up like this!
J.M. Gabrielse
Resources • http://www.education.rec.ri.cmu.edu/roboticscurri culum/vex_online/lessons/mechanics/torque/me chanics_torque.html
• Inventor’s Guide: 3·10 J.M. Gabrielse