Fixed-time passivity of coupled quaternion-valued neural networks with multiple delayed couplings

This paper investigates the fixed-time passivity of coupled quaternion-valued neural networks (CQVNNs) with multiple delayed couplings. Different from the finite-time passivity proposed in Wang et al. (IEEE Trans Cybern 50(5):2014–2025, 2020 ), a novel concept of fixed-time passivity is considered in this paper, where the settling time is independent on initial value. Compared with the existing literature, in this work we extend the passivity problem of CNNs from real field to quaternion field. In particular, the multiple coupling delays and discontinuous activation functions are considered, which have not been investigated in previous papers yet. By designing appropriate controllers and applying inequality technique, sufficient conditions are obtained correspondingly for three different types of fixed-time passivity of CQVNNs. Finally, simulations are given to substantiate the correctness of the theoretical results.