Robot Mechanisms and Mechanical Devices Illustrated - Profe Saul

Chapter 5 Tracked Vehicle Suspensions and Drivetrains 175
Figure 5-7
Fixed road wheels
this is usually a simple passive roller or two evenly spaced between the
drive sprocket and idler.
The main types of ground support methods are
• Guide blades
• Fixed road wheels
• Rocker road wheel pairs
• Road wheels mounted on sprung axles
Guide blades are simple rails that are usually designed to ride in the V
shaped guide receivers on the track’s links. They can extend continuously
from one end to the other, and therefore are the most effective at
supporting the track along its whole length. Unfortunately, they are also
quite inefficient since there is the long sliding surface that cannot be
practically lubricated. They also produce a jarring ride for the rest of the
vehicle.
One step up from guide blades is fixed road wheels (Figure 5-7).
These are wheels on short stub-shafts solidly mounted to the robot’s
chassis. The wheels can be small relative to the track, since the thing they
roll on is always just the smooth inner surface of the track. They too produce
a jarring ride, more so than guide blades, but they are far more efficient.
Fixed rollers are a good choice for a robust track system on a robot
since ride comfort is not as important, at lower speeds, as on a vehicle
carrying a person.
The bumpy ride does hamper track efficiency, however, because the
chassis is being moved up and down by the rough terrain. Reducing this