gait generation and transition for bipedal locomotion system using morris-lecar model of central pattern generator

In this paper, we intend to improve the cpg network presented by pinto et al. based on 4cell model for bipedal locomotion systems. this model is composed of four coupled identical cells which internal dynamics of each one is described by the morrislecar nonlinear differential equation and the couplings between the cells follow the synaptic type. we exploit an elitist nondominated sorting genetic algorithm (nsga ii) to find the best set of coupling weights by which the phase differences become optimally close to the ones required for a primary bipedal gait. thus, we achieve the rhythmic signals associated with four primary bipedal gaits of walk, run, twolegged jump, and twolegged hop. also, we successfully obtain all secondary gaits corresponding to the bipedal locomotion identified by pinto et al. from the 4cell model, by symmetry breaking bifurcations of primary gaits. particularly, we are able to produce the secondary gait called “hesitation walk” through transition from primary gaits of run and twolegged jump.