Datasheet

Page 38· Applied Robotics with the SumoBot
SUMMARY
This chapter introduced a variety of mechanical adjustments you can make to the
SumoBot. Adjusting the plow angle is one important consideration. Managing the pause
time between servo pulses is another important consideration because it can result in
slower servo motor operation. Frictional forces are yet another important consideration.
There are two ways to increase the friction between the SumoBot's tire treads and the
competition ring. The first is to increase the SumoBot's weight. Adding mass to get it to
the maximum allowed 500 g can make a significant difference. Choosing a tire tread
material that features the highest possible coefficient of friction between the tread and
ring surfaces is a second way to increase the friction forces. These friction forces are
what will make it possible for your SumoBot to push harder against its opponent.
This chapter introduced several experimental approaches along the way. Adjusting the
SumoBot's plow involved trial and error. Testing for servo speed involved percent
difference calculations. Testing for frictional forces involved designing and building a
pulley system to test and quantify forces of static and kinetic friction between the tire
tread and sumo ring. The friction forces activity also introduced a number of physics
principles including static and kinetic friction and their coefficients. Free body diagrams
were also introduced as a way to analyze the sum of the forces acting on an object. Free
body diagrams were also applied to the SumoBot to analyze the forces involved in the
pulley experiment.
Questions
1. What does the Reset_Button routine in Forward100Pulses.bs2 do?
2. How many servo control pulses does Forward100Pulses.bs2 send to a servo
signal line?
3. How does the
PULSOUT command control servo speed?
4. How is reducing the left servo speed different from reducing the right servo
speed?
5. What sensor considerations have to be made with regards to the maximum time
between servo pulses?
6. What's the equation for percent speed reduction when comparing a faster and
slower servo?
7. What's the difference between force and mass?
8. What's the SI unit of force?
9. What's the SI unit for acceleration?