Abstract: A module forming a mechanical actuator of the muscle or fluidic bladder type, capable of being used on a robot. The module includes: first and second sealed end couplings/connectors provided with fluid supply/circulation elements; and a flexible shell/membrane arranged between the first and second end couplings. The flexible shell is capable of deforming between an inflated state, when an inflation fluid is introduced into the shell, and a deflated state, when the inflation fluid is discharged/removed from the shell. Passage of the shell from one state to the other transmits/applies a force and/or a translational movement. At least one flexible sheath in the form of a tube is arranged inside the shell and opens at the end connectors, providing a passage extending longitudinally through the module. The flexible sheath is fluid-tight and forms, with the shell and the end connectors, an inflation chamber into which the inflation fluid is introduced.