Page 220 - LEGO MINDSTORMS - Robotics Invention System-2 Projects

Robot 8 • The ULK (Useful LEGO Knowledge)

The ULK is a differential drive robot with an arm that can pick up small
objects like LEGO bricks. Using only two motors, ULK can drive forward, turn,
raise and lower its arms, and open and close its fingers. All of this is made pos-
sible by some sophisticated mechanical design. A ratchet splitter uses one
motor for both locomotion and steering. A clever lifting mechanism allows a
second motor to perform all the arm related functions.
ULK is based on a robot I saw in Jonathan Knudsen’s book, The Unofficial
Guide to LEGO MINDSTORMS Robots. Jonathan’s robot, named Minerva
(www.oreilly.com/catalog/lmstorms/building/minerva1.5) after the ancient
roman goddess of wisdom, performed all of the same actions that ULK is
capable of, however ULK performs these actions using different mechanisms.
Jonathan’s Minerva was, in turn, based on Ben Williamson’s FetchBot
(http://ozbricks.com/benw/lego/fetchbot/index.html). Jonathan modified Ben’s
three motor design so it could be built using only the parts in the Robotics
Invention System (RIS) 1.0 kit. Unfortunately, due to changes in the RIS parts
inventory, Minerva cannot be built by solely using neither the RIS 1.5 nor the
RIS 2.0 sets. ULK is the latest in the FetchBot and Minerva ancestry, and can
be built using only the parts available in RIS 2.0 set.

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