CS 295  Special Topics in CS:  Intro to Mobile Robots

Winter 2002,                Instructor:  Jeffrey Horn

HOMEWORK 1:  Stimulus-Response Brains (Digital Braitenberg Vehicles)
 

Handed out/Assigned:	Thursday, Jan. 31, 2002
Due:	Tuesday, Feb. 5, 2002

(1)  DIGITAL Braitenberg Vehicle 1:
 
 

  Assume two inputs and two outputs.  Input is from an IR proximity detector, similar to ours but different.  Assume the following detector geometry:

 
So a "01" input vector would mean something detected to the right, but nothing center or left, while "11" would mean something in the center (or something left and right!).  Also assume a finite detector range, defined by an arc (not shown above) with its center at the robot's center.

We have two binary outputs, one for each motor.  LM is left motor, RM is right.  A "0" output means no power to the motor, while a "1" means go forward.  (so an output of 01, which is 0 to the left and 1 to the right motor, would result in an arcing turn to the left, while 10 would be a right turn)
 

Here is an example truth table (ie., a "brain") for a strategy to move toward obstacles (hopefully!):

 

INPUTS			OUTPUTS
LS	RS		LM	RM
0	0		1	0
0	1		1	0
1	0		0	1
1	1		1	1


(1A)  Fill in the following blank truth table for a strategy to move AWAY from obstacles:

 

INPUTS			OUTPUTS
LS	RS		LM	RM
0	0
0	1
1	0
1	1

(1B)  Fill in the following blank truth table for the "Wall-hugger" strategy.  This strategy should cause the robot to "look" for an obstacle, then try to keep the obstacle on its right (or left, your choice, but stick with it and be consistent).  If this obstacle is a wall, the robot should follow it.  If it is a "point" obstacle, or otherwise small, the robot should go into "orbit" around it.  Think about it!
 

INPUTS			OUTPUTS
LS	RS		LM	RM
0	0
0	1
1	0
1	1




(1C)  Fill in the following blank truth table for the "Obstacle Worship" strategy.  This strategy should cause the robot to "look" for an obstacle, then try to keep the obstacle directly in front of it.   That is, wander until detecting an object, then center the object in front of it and stop. If the obstacle moves away (i.e., moves left or right or out of range entirely), then go looking for it again.  

 

INPUTS			OUTPUTS
LS	RS		LM	RM
0	0
0	1
1	0
1	1