| Stair-Climbing Robots -- Design and Construction, Part 1 |
From "Robot Rivals"
episode DROB-106 |
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The "Surprise Item" The teams are given a "surprise" household mechanical-item from which they may make use of any of the functional parts by incorporating those parts into their robot. The team that makes use of the most functional parts receives a 10-second head-start in the competition that takes place at the end of the design and construction period. The surprise item for today's competition is a wheelchair.
Activity Log: Lousiana Tech (Hours 1 - 2)
- Louis sketches a robot that uses two large wheels, each with four revolving spokes and differential drive motors, to pull itself up the flight of stairs
- Louisiana scraps their original design. To save valuable time, they decide to use the entire pre-assembled wheelchair as the robot's chassis.
- Recognizing that the wheelchair is collapsible, Louis suggests the addition of reinforcing crossbeams to keep the frame rigid.
- David removes the rear wheels from the wheelchair, planning to add motors and reinsert the wheels at a lower axis point. This modification will lift the wheelchair to a greater angle and improve its ability to mount the stairs.
Activity Log: Southern Utah University (Hours 1 - 2)
- Jared suggests the simple and rugged construction of a tank design with a pair of tracks set 2 feet apart, or half the width of the stairs.
- Tracy fleshes out Jared's idea on the design board. Each 32-inch tank track will consist of attachment chain linked around two 4-inch sprockets. A pneumatic air ram will lift the tank up towards the first few stairs.
- Jared hammers a screw into the attachment chain to knock out a pin that holds two particular links together. This allows him to break the loop and fit the chain to the specific dimensions of their tank using a master link.
- The tank design requires more motors than Brian has in his Robot Rivals lab, so David trades Louisiana Tech a large rear wheel from their wheelchair for two NPC-2212 dual-output right-angle shaft motors.
Expert Corner: Buzz Dawson discusses the physical principles of friction and resistance. Friction is the resistance created by moving one body while in contact with another. This can be a constructive force as a source of traction, but it can also be a damaging force as a source of heat. Several products exist to moderate its affects on robot operation, such as lubricating oil and ball bearings. The electrical equivalent of friction is called resistance and is also capable of producing extreme amounts of heat. In robotics, it's important to know when friction should be exploited and when it should be avoided.
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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