Multirobot System to Explore Unknown Environment with Connection Maintenance

Table 1

Comparison of the various frontier-based exploration approaches.

Sl. no.	Approach	Type	Communication/coordination/complete/base station	Type of environment	No. of robots	Exploration time
1	Yamauchi [14]	Frontier-based	Flexible/decentralized/yes/no	Office ()	5	1000 seconds (communication range 25-size of the grid cell)
2	Simmons et al. [15]	Frontier-based	Perfect/centralized/no/no	Single corridor ()	3	200 seconds
				Obstacle free ()	3	150 seconds
				15% random obstacles ()	3	250 seconds
3	Vazquez & Malcolm [16]	Frontier-based	Perfect/decentralized/yes/no	Office(10.2 m^2)	10	500 seconds	(1 m communication range)
				Office (23.5 m^2)	10	1200 seconds
4	Burgard et al. [17]	Frontier-based	Flexible/hybrid/yes/no	Unstructured	5	6 minutes	2.5 communication range/max. distance in map%
				Office	5	7 minutes
				Corridor	5	6.5 minutes
5	Sheng et al. [18]	Frontier-based	Perfect/centralized/yes/yes	Square ()	5	6.5 minutes (communication range 24-size of grid cell)
6	Rooker & Brik [19]	Frontier-based	Perfect/centralized/yes/yes	Office ()	5	1000 seconds (communication range 25-size of the grid cell)
7	Pei et al. [20]	Frontier-based	Perfect/centralized/yes/yes	Garden	10	100 seconds
8	Kovács et al. [21]	Frontier-based	Perfect/centralized/no/yes	Obstacle free	7	62 time unit
9	Dai et al.[22]	Market economy-based	Flexible/distributed/yes/no	Obstacle free	2	550 time units
				Geometrics		620 time units
				Line segments		650 time units
10	Lauri & Ritala[23]	POMDP-based and frontier-based	No/no/yes/no	Office environment ()	1	400 seconds