Transfer of energy is accomplished through three basic means: The gear, the belt,
and the chain.
Statics deals with forces and their effect on a body at rest. Dynamics is the study
of force as it works on a rigid body in motion.
Figure 1. TRANSFER OF ENERGY FROM THE MOTOR TO THE END EFFECTOR
Work Of the Manipulator
• Work performed by a manipulator is
defined as the movement of an object
through distance.
• W=DxF
• D= Distance object moved
• F = force exerted
• Power = D x F / T
• T = time in seconds
Figure 2.
ELECTRIC MOTOR AND A WEIGHT
Energy & Torque
•
•
•
•
•
Energy is the capacity to do work.
PE = W x H
W = weight of the part
H = Height to the ground
KE = ½ M V2
• V = (2gD) 0.5 g = 32 ft/s2
• Torque is the turning effort that is
required to rotate a mass through
a radius.
• T=FxD
GEARS
•
Figure 3. SPUR GEAR DIMENSIONS
Gearing is the
transmission
of energy or
power through
the meshing or
contact of the
teeth of the
gear.
Gear
• Drive Gear = Pinion
• Driven Gear = Output Gear
• Circumferences is called pitch
circles
• Pitch diameter, pitch radius
• Center distance
Figure 4.
SPUR GEAR TERMINOLOGY
Gear Ratio
Even Number of Gears
Rotation dir. of output gear is opposite to
input gear rotation dir.
Odd No. of Gears
Rotation dir. of output gear is the same as
the input gear rotation dir.
ND = No. of teeth on a driven gear
NA = No. of teeth on a driver gear
Gear Ratio or GR = ND / NA
GEAR TRAINS
• Planetary Gear
• Stationary Gear = Sun Gear
• Rotational Gear = Planet Gear
• In the simple gear train, each
gear has its own shaft.
• In the compound gear train,
several gears can be connected
to one gear shaft.
V-BELT
•
•
Because of the physical location of components in many robots the energy
transfer is through belts.
The belt used in our robots is Synchronous Belt. Has evenly spaced teeth on
the contact surface. More expensive than V-Belt but provides more positive
contact with the pulley. It is also called “Timing Belt” and it should be used
where direction of rotation constantly changes.
ADJUSTING BELT TENSION