PLANNER
• To find a sequence of actions to accomplish some specific 
task
• Plans are created by searching through a space of actions 
until the sequence necessary to accomplish the task is 
discovered
• Planning relies on search techniques but there are 
differences
– In planning, the state of the world maybe considerably more 
complex
– In planning we need to characterize what is not changed by a 
particular action e.g. if robot arm picks up a block, it does not 
change locations of doors and other objects. 
– Specification of what is true in one state of the world and what 
changes in performing some action is called the frame problem
user