A Two-Stage Path Planning Method for the Rearrangement Problem in Modular Puzzle-Based Storage System

Table 1

Notation.

Symbol	Definition
	An order of a picking module, indicating a target state of the picking module.
	Length of the order.
	Current state of the picking module, where is the type of item in slot j.
	A set of subsequences composed of i serial numbers taken from Q.
	A subsequence composed of i serial numbers taken from Q.
	A set of subsequence composed of i serial numbers taken from
	A subsequence composed of i serial numbers selected from
	A matched group determined only by and .
	The number of matched items, which is also the length of or .
	A set of matched groups.