Page 81 - Introduction to AI Robotics

64
Exercise 2.5 2 The Hierarchical Paradigm
Describe the mission planner, navigator, pilot organization of the Nested Hierarchical
Controller. Write down how it would handle the problem in Sec. 2.2.2.

Exercise 2.6
List 2 advantages and disadvantages of the Hierarchical Paradigm.

Exercise 2.7
Solve the following navigation problem using Strips. Return to the world in Sec 2.2.2.
The robot will move to the box B1 and pick it up.
a. Add a new operator pickup to the difference table.
b. Use the world model, difference table, difference evaluator to construct a plan.
Failed preconditions and new subgoals should be shown after each step.
c. Show the changes in the world model after each operator is applied.

Exercise 2.8
Name and evaluate one representative Hierarchical architecture in terms of: support
for modularity, niche targetability, ease of portability to other domains, robustness.
Exercise 2.9 [World Wide Web]
Search the web for interactive versions of Strips and experiment with them.

2.9 End Notes

A robot that did take a cross-country trip.
Robot vehicles do in fact need special authorization to drive on public roads. In
1996, the Carnegie Mellon University Navlab vehicle project led by Dean Pomerleau
steered itself (the driver handled the gas pedal and brakes) over 90% of the way across
the USA from Washington, DC, to Los Angeles in the “No Hands Across America”
trip. The Navlab (a modified Saturn station wagon) was reportedly pulled over by
the Kansas State Highway Patrol for driving an experimental vehicle without permis-
sion. The entire trip was placed in jeopardy, but eventually the Navlab was allowed
to continue, and the team and vehicle appeared on the David Letterman show in
Los Angeles. As impressive as the Carnegie Mellon feat was, a group of German
researchers under the direction of Ernst Dickmanns and Volker Graefe have been
fielding even more advanced autonomous highway driving vehicles since 1988.
Shakey.
It can be debated whether Shakey is really the first mobile robot. There was a tortoise
built by Grey Walter, but this was never really on the main branch of AI research. See
Behavior-Based Robots 10 for details.