| Stair-Climbing Robots -- Design and Construction, Part 4 |
From "Robot Rivals"
episode DROB-106 |
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finishing touches. After time runs out, the competition will soon follow.
Activity Log: Louisiana Tech (Hours 7 - 8)
- Louisiana mounts the third wheel to the robot. The extruded aluminum assembly is held together by fastening nuts and screws, while the half-inch shaft is held in place by shaft collars on either side of the extruded framing.
- Preliminary testing reveals a substantial lack of wheel traction, so Louisiana drills screws directly into the tires. The projecting screws will dig into the stairs more sharply than bare tires can.
- Further testing provides promising results, but greater traction is needed. David adds more screws to the wheels, while Nick fashions new spacers for the hubs of the wheels out of inline skate wheels. He grinds out the center of the wheel to accommodate the size of the existing hub.
- A third round of tests exposes yet another obstacle. The robot pulls to the right, because the right wheel moves slower than the other. Nick believes a recalibration of the speed control system will solve the problem. However, they do not have time for further testing after these adjustments are made.
Activity Log: Southern Utah University (Hours 7 - 8)
- Southern Utah performs a successful test of their wheel's drive motor.
- Jared mounts the electronics onto the robot using a sheet of metal from the wheelchair.
- With Brian's guidance, Southern Utah decides to run two speed controllers for each separate motor just in case the robot is running over current. They use a Y-connector to split one signal from the radio into two signals; each amplifier will receive identical signals from the radio so that they run the same.
- After initial tests, Jared rewires the robot and the team improves their competition strategy.
- A straight line up the stairs must be taken. Otherwise, the angle will twist the attachment chain from the sprockets' teeth. A third test proves successful.
Expert Corner: Brian discusses the electrical measurement of voltage. It is a common misconception that voltage is equal to power. Voltage is in fact the difference in electrical charge between two points in a circuit. In other words, it represents a potential energy above ground level. Imagine two buckets of water sitting on a flight of stairs, each with a hose running to a single basin. The first bucket is set much higher than the second; therefore, the water running out of the first will flow much stronger than the second. This provides an apt analogy for differences in voltage. While each bucket produces a current that flows into the basin at ground level, the first bucket has a higher voltage level than the second bucket and therefore more potential energy.
RESOURCES :
Robot Builder's Bonanza
Model: 0071362967
Author: Gordon McComb
Build Your Own Robot!
Model: 1568811020
Author: Karl Lunt
Robots, Androids and Animatrons : 12 Incredible Projects You Can Build
Model: 0070328048
Author: John Iovine
Personal Robotics : Real Robots to Construct, Program, and Explore the World
Model: 156881089X
Author: Richard Raucci
Mobile Robots : Inspiration to Implementation
Model: 1568810970
Author: Joseph L. Jones, et al
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