In this work, we present a problem of simultaneous input-output feedback
linearization and decoupling (non-interacting) for mechanical control systems
with outputs. We show that the natural requirement of preserving mechanical
structure of the system and of transformations imposes supplementary conditions
when compared to the classical solution of the same problem for general control
systems. These conditions can be expressed using objects on the configuration
space only. We illustrate our results with several examples of mechanical
control systems