Different Types of Robots Robot Arms (Fixed Robots) Mobile Robots Humanoid Robots Legged Robots Wheel Robots 3 wheels 2 Driver wheels, 1 Caster 1 Driver wheel, 2 Casters 4 wheels Casters make diverse problems in the control of the robot Wheel Robot Main Components Main Components
We are now discussing some of the above topics
P = (T . w) = cte.
Different Transmission Systems
So w => T
Consider a pair of gears that are meshed together.
A torque on this axle...
…produces a force at the tooth.
The moment arm is the radius of the gear.
Remember: t = F x r
the large gear’s tooth. This creates an equal (and opposite)
force in the large gear. This is Newton’s 3rd Law.
…and produces a
larger torque on this axle.
The force acts through this larger moment arm...
F1 = -F2
t1 = F1 x r1
t2 = F2 x r2
Analyzing the forces...
The ratio of torques is the ratio of the gear radii.
This is the gear ratio!
The gear ratio of this gear box is 75 to 1
That means the last axle rotates 75 times slower than
the first axle. It also means the last axle has 75 times
the torque as the first axle.
Have one person turn
And have another person
try to hold on to this wheel.
on something. This is known as mechanical advantage.
BUT, it comes at a price. Do you know what it is?
(center shaft to center shaft)
for DR, can use NEMA frame
Speed Ratio = 2.5
Ratio always greater than 1