Design of stable walking gaits for biped robots with several underactuated degrees of freedom

Dynamic walking gaits are theoretically reflected by theperiodic solutions exhibited by nonlinear impulsive dynamicalsystems [1]. In practice, such solutions, knownas limit cycles, can exist either as a natural responseof the system, e.g. passive walkers, or by the use offeedback control. Analytically, finding these solutionsis certainly challenging, and the complexity of the problemincreases considerably if a mixture in between passiveand actuated joints are considered, i.e. underactuatedrobots