Notes on robot design - see also [[lirec notes]] & [[category robotics]].

Robotics is the intelligent connection of perception to action" - Michael Brady

  * Perception: Sensors tell a robot about the outside world.
  * Action: Actuators allow a robot to change the outside world, to act upon it.
  * Intelligence: Some sort of controller

====State====

State is what the robot collects in order to understand the world.

(not too happy about these definitions...)

  * Internal state: Directly observable state of the robot. Also it's internal representation of the world - it's internal model.
  * External state: What's happening in the real world. Can only be known via a robot's sensors.
  * Observable state: known at all times, usually internal - eg. battery state.
  * Partially observable state: Through a sensor, along with noise eg: camera image pixels
  * Hidden state: What you are actually interested in, in the real world - eg: position of user's head. Can't be directly known, must be indirectly inferred from (maybe multiple) sensors. See [[sensor fusion]].

====Controllers====

Deliberative vs Reactive

===Think hard - then act!===
  * Capable of learning and prediction
  * Finds strategic solution
but:
  * Requires lots of computation - eg. brute force search for potential plan
  * Needs a world model
  * Slow

For example : [[http://www.sri.com/about/timeline/shakey.html|Shakey]], the first robot built with a planning AI system (running on a PDP-10 and PDP-15 computer).

===Don't think, react!===
  * Fast
  * Powerful, biological parallel
but:
  * Minimal state
  * No memory
  * No internal representation of the world
  * Unable to plan ahead
  * Unable to learn

For example: [[http://smfr.org/robots/|BEAM robots]] which stands for Biology, Electronics, Aesthetics, Mechanics, and was originally invented by [[http://en.wikipedia.org/wiki/Mark_Tilden|Mark Tilden]]. 

===Or do both!===
  * Deliberative system on top
  * Reactive underneath
  * Hybrid or Behavioural system

====Links====

Artificial Intelligence versus classical Robotics:
http://www.ee.pdx.edu/~mperkows/CLASS_479/hardware/014.Robot-Control-Architectures.ppt

http://eng.upm.edu.my/~kmbs/teaching/robotics/W6.pdf