| All-Terrain Robots -- Design and Construction, Part 2 |
From "Robot Rivals"
episode DROB-108 |
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With the preliminary designs worked out, work gets fully underway on constructing the components of the robots. Activity Log: Purdue (Hours 3 - 4)
- Purdue attaches the drive motors and wheels to a 16-inch piece of extruded aluminum and begins early testing. They must find a balance between having both the speed and the control to win.
- Chris and Ross explore the possibility of using the copier frame as the chassis of their robot.
- Joe cuts two pieces of steel that will be used for the claw mechanisms.
- While Purdue presses on in construction, Brian looks to incorporate more of the copier. He converts a rigid sheet of plastic into the housing for the electronics.
- Brian and Chris develop the skid and claw mechanism so that the steel rods swing forward when the robot is stuck but remain tucked behind when locomotion is smooth.
Activity Log: University of Utah (Hours 3 - 4)
- With such a delicate machine, Utah painstakingly cuts and drills each piece of the structure and each gear to exact tolerances. If the linkage does not move smoothly, the motor will not be powerful enough to drive the legs.
- Utah has chosen a risky balloon-frame design that must be assembled all at once. Determined to keep the project organized, Dan labels all the pieces of extruded aluminum, sets out the frame on the floor, and begins to make connections without tightening the fittings.
- Utah's robot requires small yet powerful motors, so Buzz customizes the gearboxes. To every motor he fits a plate, a 4:1 reduction gear, and an output shaft to drive the sprockets of the legs.
Expert Corner Buzz discusses robotic frame-building and one of the most useful structural building materials used in robotics: aluminum. More specifically -- extruded aluminum. Buildings, cars, desktop copiers, and robots all have a supporting frame or structure called a chassis. A chassis can be made from any of a variety structural materials including wood, plastics, steel, and aluminum. Having a chassis that is both lightweight and strong is typically a key consideration in robot-building One choice that might seem intuitively to be among the best for building a chassis is steel. It is available in flat stock, but in this form steel is flimsy and may be difficult to drill. Steel that is pre-manufactured with holes avoids the difficulty of drilling but tends to be even weaker. Extruded aluminum overcomes both of those weaknesses. The type used frequently in Robot Rivals is the size of a one-inch square bar, has channels for inserting connectors (figure A), and is extremely strong. To form this configuration, aluminum is superheated until soft and malleable then is pressed through an extrusion die -- much like the dies used in children's modeling-clay sets (figure B). Once it is pressed, it is treated for durability. This process produces both the strength and the unique honeycomb shape that makes this material ideal in building robotic frameworks.
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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