“…The first results on consensus (synchronization) of a particular class of EL-agents were reported in (Rodriguez- Angeles and Nijmeijer, 2004;Chopra and Spong, 2005) and, the case of general, nonidentical, EL-systems with delays was first reported in (Nuño et al, 2011). Since then, a plethora of different controllers have been proposed to solve consensus problems, from simple Proportional plus damping (P+d) schemes (Ren, 2009;Nuño et al, 2013b,a) to more elaborated adaptive (Chung and Slotine, 2009;Nuño et al, 2011;Meng et al, 2014;Abdessameud et al, 2015;Chen et al, 2015) and sliding-mode controllers (Klotz et al, 2015).…”