This paper investigates the high-order consensus problem for the multi-agent systems with agent's dynamics described by high-order integrator, and adopts a general consensus algorithm composed of the states' coordination control. Under communication delay, consensus algorithm in usual asynchronously-coupled form just can make the agents achieve a stationary consensus, and sufficient consensus condition is obtained based on frequency-domain analysis. Besides, a predictor-based consensus algorithm is constructed via multiplying the delayed neighboring agents' states by a delay-related compensation part. In our proposed algorithm, a compensating delay is introduced to match the communication delay. Specially, the original high-order consensus is regained when the compensating delay equals to the communication delay, but cannot be achieved if the compensating delay is not equivalent to the communication delay. Moreover, sufficient consensus convergence conditions are also obtained for the agents under our predictor-based algorithm with different compensating delay. Numerical studies for multiple quadrotors illustrate the correctness of our results.
Two hypogean species of genus Triplophysa are herein described from two subterranean tributaries of the River Yangtze drainage in Guiyang City, Guizhou Province, China. Triplophysa wudangensis, new species, can be distinguished from its congeners by the combination of the following characters: eye reduced, with diameter 5.1-6.5% HL; interorbital width 33.1-35.8% HL; body scaleless; lateral line complete; posterior chamber of air bladder degenerated; anterior nostril with elongated barbel-like tip; distal margin of dorsal fin truncate; dorsal fin with 7, anal fin with 5, and caudal fin with 14 branched fin rays; vertebrae 4 + 34. Triplophysa qingzhenensis, new species, can be distinguished from its congeners by the combination of the following characters: eye reduced, with diameter 2.1-4.4% HL; interorbital width 25.1-30.4% HL; body scaleless; lateral line complete; posterior chamber of air bladder degenerated; anterior nostril with elongated barbel-like tip; distal margin of dorsal fin truncate; dorsal fin with 7-8, anal fin with 5, and caudal fin with 14 branched fin rays; vertebrae 4 + 36. Molecular phylogenetic analysis supported the validity of these two new species and indicated their close relationship with Triplophysa rosa.