On new passivity property: review and extension to mechanical rotational systems

An extension of a new passivity property (recently introduced in 2003 to nonlinear electrical systems) to rotational mechanical systems is presented in this paper. For the electrical systems case, the definition of this property supposes that one of the port variables appears as the time derivative of a physical magnitude (current or voltage) and a certain power inequality must hold. We review and extend this new passivity property to two classes of rotational mechanical systems. To this aim, we define these classes and prove that for them passivity is preserved even if we take one of the port variables as the time derivative of a physical magnitude (torque or velocity).